MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Journal of Nanomaterials' source. Wed, 17 Mar 2010 17:08:57 +0100 http://www.medworm.com/index.php?rid=3374031&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F583970.html In this study, we prepared six nanometer-sized prodrugs (nanoprodrugs) of NSAIDs, ibuprofen, indomethacin, and naproxen through the spontaneous emulsification mechanism using monomeric and dimeric derivatives of the NSAIDs. We evaluated their effect on the proliferation of U87-MG glioma cells by cell counting, WST-1 cell proliferation reagent, and propidium iodide incorporation. The two ibuprofen nanoprodrugs inhibited the cell growth more potently than the indomethacin nanoprodrugs, whereas the naproxen nanoprodrugs did not show any significant effect. Remarkably, ibuprofen did not show any effect at an equimolar concentration. Approximately, 4.4% of the ibuprofen nanoprodrugs was found in the cell, whereas no ibuprofen could be detected suggesting that the superior effect of the nano... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3374031 Wed, 17 Mar 2010 17:08:53 +0100 3374031 http://www.medworm.com/index.php?rid=3374030&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F748567.html We report high-yield and efficient size-controlled syntheses of Chalcopyrite CuInS2 nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100°C and times as short as 30 minutes. The nanoparticles sizes were 1.8 nm to 10.8 nm as reaction temperatures were varied from 100°C to 200°C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%). The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by 1H NMR using SSP 1 with 1,2-ethanedithiol and benzyl mercaptan were conducted to elucidate the formation of C... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3374030 Wed, 17 Mar 2010 17:08:53 +0100 3374030 http://www.medworm.com/index.php?rid=3339609&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F287082.html Series of biodegradable polyesters poly(butylene adipate) (PBA), poly(butylene succinate) (PBS), and poly(butylene adipate-co-butylene terephthalate) (PBAT) were synthesized successfully by melt polycondensation. The polyesters were characterized by Fourier transform infrared spectroscopy (FTIR), 1H-NMR, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC), respectively. The blends of poly(lactic acid) (PLA) and biodegradable polyester were prepared using a twin screw extruder. PBAT, PBS, or PBA can be homogenously dispersed in PLA matrix at a low content (5–20 wt%), yielding the blends with much higher elongation at break than homo-PLA. DSC analysis shows that the isothermal and nonisothermal crystallizabilities of PLA component are promoted in the pr... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3339609 Sun, 07 Mar 2010 16:37:24 +0100 3339609 http://www.medworm.com/index.php?rid=3318308&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F427689.html Core-shell-structured CdSe/SiOx nanowires were synthesized on an equilateral triangle Si (111) substrate through a simple one-step thermal evaporation process. SEM, TEM, and XRD investigations confirmed the core-shell structure; that is, the core zone is single crystalline CdSe and the shell zone is SiOx amorphous layer and CdSe core was grown along (001) direction. Two-stage growth process was present to explain the growth mechanism of the core/shell nanwires. The silicon substrate of designed equilateral triangle providing the silicon source is the key factor to form the core-shell nanowires, which is significant for fabrication of nanowire-core sheathed with a silica system. The PL of the product studied at room temperature showed two emission bands around 715 and 560 nm, which o... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3318308 Mon, 01 Mar 2010 17:50:32 +0100 3318308 http://www.medworm.com/index.php?rid=3316055&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F490679.html Chitosan-silica (CSSi) hybrid films have been fabricated by sol-gel process using tetraethoxysilane (TEOS) as precursor. The structure of the resulting hybrid has been characterized by Fourier transform infrared spectroscopy (FTIR). Fracture surface has been revealed through a field emission-scanning electron microscopy/energy dispersive spectrometer (FE-SEM/EDS) to probe the dispersion degree and the size of SiO2 particle. Study of morphology using a SEM micrograph and the High Resolution Transmission Electron Microscopy (HRTEM) images of the nanocomposite films suggests that the SiO2 nanoparticles are within the range of 2–7 nm in diameter and are uniformly dispersed in the polymer matrix. Thermal properties of these composite materials have been studied as a function of sil... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3316055 Sun, 28 Feb 2010 16:39:39 +0100 3316055 http://www.medworm.com/index.php?rid=3316054&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F416408.html Initial experiments using differentially functionalized fullerenes, CD-C60, hexa-C60, and tris-C60, suggested a properties dependent effect on cytotoxic and proliferative responses in human skin keratinocytes. In the present study we investigated the cytokine secretion profile of dermal epithelial cells exposed to functionalized fullerenes. Keratinocyte-derived cytokines affect homing and trafficking of normal and malignant epidermal immune as well as nonimmune cells in vivo. These cytokines are critical for regulating activation, proliferation, and differentiation of epidermal cells. Our results indicate that tris-C60 (size range <100 nm) significantly reduces inflammatory cytokine release in a dose- and time-dependent manner. In contrast CD-C60 demonstrated a relatively pro-in... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3316054 Sun, 28 Feb 2010 16:39:39 +0100 3316054 http://www.medworm.com/index.php?rid=3298220&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F750960.html We demonstrate two approaches to prepare mesoporous metal oxide nanowires by surfactant assembly and nanoconfinement via sol-gel or electrochemical deposition. For example, mesoporous Ta2O5 and zeolite nanowires are prepared by block copolymer Pluronic 123-templated sol-gel method, and mesoporous ZnO nanowires are prepared by electrodeposition in presence of anionic surfactant sodium dodecyl sulfate (SDS) surfactant, in porous membranes. The morphologies of porous nanowires are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3298220 Tue, 23 Feb 2010 17:18:37 +0100 3298220 http://www.medworm.com/index.php?rid=3291844&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F136860.html We study the field emission characteristics of large-area films of crystalline MoO3 microbelt grown on silicon substrate by thermal evaporation in air using a commercial infrared sintering furnace. It is found that their turn-on field, threshold field, resistance to microdischarge and field emission current stability are better than MoO3 nanowires, MoO3 nanobelts and MoO3 nanoflower. In addition, good uniform distribution of field emission sites can be observed. The physical reasons are explained responsible for such improvements on field emission characteristics of MoO3 material. These results indicate that large-area MoO3 microbelts may be suitable for cold-cathode electron source application. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3291844 Sun, 21 Feb 2010 16:36:28 +0100 3291844 http://www.medworm.com/index.php?rid=3272812&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F526128.html In order to create strong composite materials, a good dispersion of carbon nanotubes (CNTs) and nanofibers (CNFs) in a matrix material must be obtained. We proposed a simple method of growing the desirable carbon nanomaterial directly on the surface of matrix particles. CNTs and CNFs were synthesised on the surface of model object, silica fume particles impregnated by iron salt, and directly on pristine cement particles, naturally containing iron oxide. Acetylene was successfully utilised as a carbon source in the temperature range from 550 to 750∘C. 5–10 walled CNTs with diameters of 10–15 nm at 600∘C and 12–20 nm at 750∘C were synthesised on silica particles. In case of cement particles, mainly CNFs with a diameter of around 30 ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3272812 Mon, 15 Feb 2010 16:33:36 +0100 3272812 http://www.medworm.com/index.php?rid=3270992&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F962021.html Green synthesis of metal nanoparticles, such as silver or gold nanoparticles, has been attracting increasing attention in recent years. Functionalized magnetite nanoparticles have many uses in various applications, including nanoelectronic devices, molecular recognition, biomedical applications, drug delivery targeting, and optical devices. In this investigation, magnetic cores (Fe3O4) were synthesized using a fabrication method involving coprecipitation of Fe2+ and Fe3+. In the next step, magnetite-gold composite nanoparticles were synthesized with size ranging from 6–20 nm, using an ethanol extract of Eucalyptus camaldulensis as a natural reducing agent. Transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction spectroscopy, and visible absorption s... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3270992 Sun, 14 Feb 2010 16:37:51 +0100 3270992 http://www.medworm.com/index.php?rid=3262498&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F196393.html We study the protein viability on Au nanoparticles during an electrospray and electrostatic-force-directed assembly process, through which Au nanoparticle-antibody conjugates are assembled onto the surface of carbon nanotubes (CNTs) to fabricate carbon nanotube field-effect transistor (CNTFET) biosensors. Enzyme-linked immunosorbent assay (ELISA) and field-effect transistor (FET) measurements have been used to investigate the antibody activity after the nanoparticle assembly. Upon the introduction of matching antigens, the colored reaction from the ELISA and the change in the electrical characteristic of the CNTFET device confirm that the antibody activity is preserved during the assembly process. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3262498 Thu, 11 Feb 2010 16:52:25 +0100 3262498 http://www.medworm.com/index.php?rid=3262497&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F572865.html Cubic-SiC nanowires were synthesized using activated carbon powder and Si substrate in vacuum at 1200–1350°C for 1–4 hours. The nanowires were grown according to the following proposed mechanisms: (1) diffusion of C/CO into Si substrate, (2) weakening of Si bond and atomic kick-out, (3) formation of Si-C in vapor phase, (4) formation of saturated SiC layer, (5) formation of pyramid-like SiC nanostructure, and (6) formation of SiC nanowires. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3262497 Thu, 11 Feb 2010 16:52:25 +0100 3262497 http://www.medworm.com/index.php?rid=3262496&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F435451.html We report on the growth, structural characterization, and conductivity studies of Si-doped InP nanowires grown by Au-assisted molecular beam epitaxy. It is shown that Si doping reduces the mean diffusion length of adatoms on the lateral nanowire surface and consequently reduces the nanowire growth rate and promotes lateral growth. A resistivity as low as 5.1±0.3×10−5 Ω⋅cm is measured for highly doped nanowires. Two dopant incorporation mechanisms are discussed: incorporation via catalyst particle and direct incorporation on the nanowire sidewalls. The first mechanism is shown to be less efficient than the second one, resulting in inhomogeneous radial dopant distribution. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3262496 Thu, 11 Feb 2010 16:52:25 +0100 3262496 http://www.medworm.com/index.php?rid=3185213&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F261748.html A conductive nanofiller, expanded graphite (EG), was introduced into polyvinylidene fluoride (PVDF) by direct melt blending process. The electrical conductivity and dielectric properties of resulting PVDF/EG composites were investigated in a wide range of frequencies from 102 to 108 Hz. The dielectric dispersion and conductivity of the composite system exhibited a strong frequency dependence particularly in the vicinity of percolation threshold (Φc=6 vol%). Moreover, the dielectric permittivity tended to decrease with increasing frequency while the conductivity displayed a reverse trend. A large permittivity was found in the composite having EG content near Φc. Accordingly, percolation concept and biased random walk approach can be used to describe the carrier tran... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3185213 Tue, 19 Jan 2010 16:57:34 +0100 3185213 http://www.medworm.com/index.php?rid=3180218&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F758353.html Single crystalline Nb2O5 nanorods have been successfully synthesized by a soft chemical process, in which only metal Nb powder and water were used as the starting materials. The synthesized Nb2O5 nanorods are highly crystalline and their growth is along [001] direction. The diameter of the nanorods is found to be ca. 50 nm and their lengths up to several micrometers. Based on the experimental results of XRD, SEM, and TEM measurements, the possible mechanism for the formation of Nb2O5 nanorods was discussed. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3180218 Sun, 17 Jan 2010 16:27:49 +0100 3180218 http://www.medworm.com/index.php?rid=3180217&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F514124.html A series of polyurethane (PU) and vinyl ester resin (VER) simultaneous and gradient interpenetrating polymer networks (represented as s-IPN and g-IPN, resp.) curing at room temperature were prepared by changing the component ratios of PU or VER in s-IPN, time intervals, and component ratio sequences of s-IPN in g-IPN. The microstructures of s-IPN and g-IPN were detected by atomic force microscope (AFM), dynamic mechanical analyzer (DMA), and surface constitution scanning of nitrogen element of energy dispersive X-ray spectrum (EDX), respectively. The mechanical properties of s-IPN and g-IPN were studied by values in strain-stress curves detected by electronic multipurpose tester. The results indicated that the morphology and mechanical properties are both affected by PU/VER component ratio... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3180217 Sun, 17 Jan 2010 16:27:49 +0100 3180217 http://www.medworm.com/index.php?rid=3133527&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2010%2F898910.html The objective of this study was to investigate the potential of water soluble chitosan as a carrier in the preparation of protein-loaded nanoparticles. Nanoparticles were prepared by ionotropic gelation of water-soluble chitosan (WSC) with sodium tripolyphosphate (TPP). Bovine serum albumin (BSA) was applied as a model drug. The size and morphology of the nanoparticles were investigated as a function of the preparation conditions. The particles were spherical in shape and had a smooth surface. The size range of the nanoparticles was between 100 and 400 nm. Result of the in vitro studies showed that the WSC nanoparticles enhance and prolong the intestinal absorption of BSA. These results also indicated that WSC nanoparticles were a potential protein delivery system. (Source: Journal ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3133527 Thu, 31 Dec 2009 16:22:39 +0100 3133527 http://www.medworm.com/index.php?rid=3133526&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F429360.html Boron nitride (BN) nanostructures are structural analogues of carbon nanostructures but have completely different bonding character and structural defects. They are chemically inert, electrically insulating, and potentially important in mechanical applications that include the strengthening of light structural materials. These applications require the reliable production of bulk amounts of pure BN nanostructures in order to be able to reinforce large quantities of structural materials, hence the need for the development of high-yield synthesis methods of pure BN nanostructures. Using borazine (B3N3H6) as chemical precursor and the hot-filament chemical vapor deposition (HFCVD) technique, pure BN nanostructures with cross-sectional sizes ranging between 20 and 50 nm were obtained, in... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3133526 Thu, 31 Dec 2009 16:22:39 +0100 3133526 http://www.medworm.com/index.php?rid=3071011&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F308276.html We present quantum chemical investigations on magnetic properties of several Co6On (n=0–9,12) nanoparticles. The results of calculations show, that only Co6, and Co6O8 particles display paramagnetic properties while other nanoparticles investigated reveal diamagnetic ones. The reason of the derivative paramagnetizability is discussed here. Calculations reveal that the stability of these compounds increases with the increase of the number of O atoms. The limit when the future increase of oxygen atoms does not change binding energy per atoms remarkably is found. The reason why the O atoms could stabilize the Co nanoparticles and change magnetic properties of them is discussed. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3071011 Wed, 09 Dec 2009 16:24:56 +0100 3071011 http://www.medworm.com/index.php?rid=3066917&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F138490.html Lyophilized YAG gel, synthesized by the coprecipitation technique, has been sintered to transparency by spark plasma sintering method at 1500∘C. Whereas conventionally dried gels show large agglomerates, over 1 μm, powders from lyophilized gels show no agglomeration with an average particle size below 100 nm. The absence of agglomerates affects on the optical properties of the sintered materials: conventionally dried powders are opaque after sintering, whereas 0.8 mm thick transparent YAG materials with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range have been obtained for the lyophilized gels. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066917 Tue, 08 Dec 2009 16:23:32 +0100 3066917 http://www.medworm.com/index.php?rid=3066916&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F637530.html (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066916 Tue, 08 Dec 2009 16:23:32 +0100 3066916 http://www.medworm.com/index.php?rid=3066915&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F685624.html Cs Y2F7: 78%   Y3+, 20%   Yb3+, 2%   Er3+ nanocrystals with a mean diameter of approximately 8 nm were synthesized at   185°C in the high boiling organic solvent N-(2-hydroxyethyl)-ethylenediamine (HEEDA) using ammonium fluoride, the rare earth chlorides and a solution of caesium alkoxide of N-(2-hydroxyethyl)-ethylenediamine in HEEDA. In parallel with this approach, a microwave assisted synthesis was carried out which forms nanocrystals of the same material, about 50 nm in size, in aqueous solution at 200∘C/8 bar starting from ammonium fluoride, the rare earth chlorides, and caesium fluoride. In case of the nanocrystals, derived from the HEEDA synthesis, TEM images reveal that the particles ar... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066915 Tue, 08 Dec 2009 16:23:32 +0100 3066915 http://www.medworm.com/index.php?rid=3066914&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F486979.html In nanoscale regime as the CMOS process technology continues to scale, the standard copper (Cu) interconnect will become a major hurdle for onchip communication due to high resistivity and electromigration. This paper presents the comprehensive evaluation of mixed CNT bundle interconnects and investigates their prospects as a low power high-speed interconnect for future nanoscale-integrated circuits. The performance of mixed CNT bundle interconnect is examined with carbon nanotube field effect transistor (CNFET) as a driver and compared with the traditional interconnect, that is, CMOS driver on Cu interconnect. All HSPICE simulations are carried out at operating frequency of 1 GHz and it is found that mixed CNT bundle interconnects with CNFET as the driver can potentially provide a ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066914 Tue, 08 Dec 2009 16:23:32 +0100 3066914 http://www.medworm.com/index.php?rid=3066913&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F257892.html Water-soluble DNA-wrapped single-wall and double-wall carbon nanotubes (DNA-SWNTs, DNA-DWNTs) have been well separated by length incorporating size-exclusion high-performance liquid chromatography (HPLC). The morphology and electronic properties of the size- (length-) separated DNA-SWNTs and -DWNTs are investigated by atomic force microscopy (AFM), photoluminescence (PL), and Raman spectroscopy. By using length-separated DNA-SWNTs and -DWNTs, we have found that PL intensity of the DNA-SWNTs varies sensitively depending not only on the chirality (or diameter) but more importantly on the length of the hybrids. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066913 Tue, 08 Dec 2009 16:23:32 +0100 3066913 http://www.medworm.com/index.php?rid=3066912&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F815734.html Quantum dot (QD) nanocrystals which have important optical properties, in particular, the wavelength of their fluorescence, depend strongly on their size. Colloidal QDs once dispersed in a solvent are quite interesting fluorescence probes for all types of labelling studies because of their reduced tendency to photo bleach. In this review, we will give an overview on how QDs have been used so far in cell biology. In particular, we will discuss the biologically relevant properties of QDs and focus on four topics: labeling of cellular structures and receptors with QDs, incorporation of QDs by living cells, tracking the path and the fate of individual cells using QD labels, and QDs as contrast agents. QDs are seen to be much better in terms of efficacy over radioisotopes in tracing medicine in... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066912 Tue, 08 Dec 2009 16:23:32 +0100 3066912 http://www.medworm.com/index.php?rid=3066911&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F892178.html PtRu nanoparticles with a diameter of 10–15 nm were electrodeposited within multiwalled carbon nanotube-Nafion (MWCNT-Nafion) nanocomposite. The formation of PtRu nanoparticles in MWCNT-Nafion nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The electrocatalytic activity towards the methanol electrooxidation at PtRu-MWCNT-Nafion and Pt-MWCNT-Nafion nanocomposite-modified glassy carbon electrodes was investigated by cyclic voltammetry. The results indicated that the PtRu-MWCNT-Nafion nanocomposite was electrocatalytically more active than Pt-MWCNT-Nafion nanocomposite. The effect of atomic ratio of Pt : Ru on the electrocatalytic ability towards the methanol electrooxidation was investig... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066911 Tue, 08 Dec 2009 16:23:32 +0100 3066911 http://www.medworm.com/index.php?rid=3066910&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F840791.html We studied the optoelectronic properties of the InGaN/GaN multiple-quantum-well light emitting diodes (LEDs) and single-junction GaAs solar cells by introducing the luminescent Au nanoclusters. The electroluminescence intensity for InGaN/GaN LEDs increases after incorporation of the luminescent Au nanoclusters. An increase of 15.4% in energy conversion efficiency is obtained for the GaAs solar cells in which the luminescent Au nanoclusters have been incorporated. We suggest that the increased light coupling due to radiative scattering from nanoclusters is responsible for improving the performance of the LEDs and solar cells. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066910 Tue, 08 Dec 2009 16:23:32 +0100 3066910 http://www.medworm.com/index.php?rid=3066909&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F716242.html Biocompatible poly(propylene-co-butylene succinate) (PPBSu) copolyesters, containing up to 50 mol% butylene succinate units, were synthesized by the two-stage melt polycondensation method (esterification and polycondensation). The copolymers were fully characterized and biocompatibility studies were also performed. They were proved to be biocompatible and they were used as polymer matrices for the preparation of drug loaded nanoparticles. Nimodipine was selected as a model hydrophobic poorly water soluble drug. From the results obtained by dynamic light scattering (DLS) and scanning electron microscopy (SEM), drug loaded copolymer nanoparticles were found to exhibit a spherical shape and their mean diameter appeared in the range of 180–200 nm. Fourier Transformation... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066909 Tue, 08 Dec 2009 16:23:32 +0100 3066909 http://www.medworm.com/index.php?rid=3066908&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F264026.html The boron-nitride (BN) nanocages are synthesized by nitrogenation of amorphous boron nanoparticles at 1073 K under nitrogen and ammonia atmosphere. The BN nanocages exhibit a well-crystallized feature with nearly pentagonal or spherical shape, depending on their size. High-resolution transmission electron microscopy studies reveal that they are hollow nanocages. The growth mechanism of the BN nanocages is proposed. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066908 Tue, 08 Dec 2009 16:23:32 +0100 3066908 http://www.medworm.com/index.php?rid=3066907&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F384601.html Electrochemical characterization of the uniformly dispersed Pt and Ag nanodots synthesized after in situ scalable electron-beam reduction on copper grid and carbon-fiber electrode is demonstrated. By employing plasma pretreatment to produce functional organosilicon micronetworks-based reaction sites on copper grid, the size and standard deviation of the electrochemically reduced metallic nanodots can be strictly confined. When detuning the accelerating voltage of electron-beam from 3 to 120 kV, the reshaped nanodot diameter enlarges from 12.7±0.8 to 18.3±3.6 nm due to the gradual self-aggregation. In comparison with sputtering method, the electroactivity of Pt nanodot covered carbon fiber electrode obtained after electron-beam reduction exhibits a larger electro... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066907 Tue, 08 Dec 2009 16:23:31 +0100 3066907 http://www.medworm.com/index.php?rid=3066906&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F309208.html Dendritic networks of nanoscopic grooves measuring 50–75 nm wide by <50 nm deep occur on the walls of vesicles in the glassy margins of mid-ocean ridge pillow basalts worldwide. Until now, their exact origin and significance have remained unclear. Here we document examples of such grooved patterns on vesicle walls in rocks from beneath the North Atlantic Ocean, and give a fluid mechanical explanation for how they formed. According to this model, individual nanogrooves represent frozen viscous fingers of magmatic fluid that were injected into a thin spheroidal shell of hot glass surrounding each vesicle. The driving mechanism for this process is provided by previous numerical predictions of tangential tensile stress around some vesicles in glassy rocks upon cooli... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066906 Tue, 08 Dec 2009 16:23:31 +0100 3066906 http://www.medworm.com/index.php?rid=3066905&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F439389.html Nanoscience and Nanotechnology have found their way into the fields of Biotechnology and Medicine. Nanoparticles by themselves offer specific physicochemical properties that they do not exhibit in bulk form, where materials show constant physical properties regardless of size. Antibodies are nanosize biological products that are part of the specific immune system. In addition to their own properties as pathogens or toxin neutralizers, as well as in the recruitment of immune elements (complement, improving phagocytosis, cytotoxicity antibody dependent by natural killer cells, etc.), they could carry several elements (toxins, drugs, fluorochroms, or even nanoparticles, etc.) and be used in several diagnostic procedures, or even in therapy to destroy a specific target. The conjugation of anti... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066905 Tue, 08 Dec 2009 16:23:31 +0100 3066905 http://www.medworm.com/index.php?rid=3066904&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F238206.html Mg-Al Hydrotalcite-like clay (LDH) intercalated with diclofenac anions (HTlc-DIC) was introduced into poly(ε-caprolactone) (PCL) in different concentrations by the electrospinning technique, and mats of nonwoven fibers were obtained and compared to the pristine pure electrospun PCL. The fibers, characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry, show an exfoliated clay structure up to 3 wt%, a good thermal stability of the diclofenac molecules and a crystallinity of PCL comparable to the pure polymer. The scanning electron microscopy revealed electrospun PCL and PCL composite fibers diameters ranging between 500 nm to 3.0 μm and a generally uniform thickness along the fibers. As the results suggested the i... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066904 Tue, 08 Dec 2009 16:23:31 +0100 3066904 http://www.medworm.com/index.php?rid=3066903&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F914501.html Bare cadmium sulfide (CdS) nanocrystals were successfully synthesized by the thermolysis of a single-source organometallic precursor, cadmium chloride hemipentahydrate (CdCl2⋅2.5H2O) with thiourea in ethanol. The microstructure of the CdS samples was characterized using XRD, TEM, and Raman spectroscopy. The XRD's results showed that there was a transformation from cubic to hexagonal crystalline phase when higher mass of CdCl2⋅2.5H2O was used. Further experimental with different Cd2+ source showed ion Cl− originated from CdCl2⋅2.5H2O attributed to this crystalline phase transformation. The UV-Visible analysis indicated that quantum confinement effect took place when compared to the bulk CdS. However, the photoluminescence experiments revealed that the red-lig... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=3066903 Tue, 08 Dec 2009 16:23:31 +0100 3066903 http://www.medworm.com/index.php?rid=2727047&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F140586.html (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2727047 Mon, 24 Aug 2009 14:03:23 +0100 2727047 http://www.medworm.com/index.php?rid=2695285&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F101870.html The impact fracture behavior of a vapor grown carbon nanofiber (VGCNF) reinforced high-density polyethylene (PE) composite was evaluated. The samples consisting of pure PE and composites with 10 wt% and 20 wt% of VGCNFs were prepared by a combination of hot-pressing and extrusion methods. Extrusion was used to produce samples with substantially different shear histories. The fracture behavior of these samples was analyzed using the essential work of fracture (EWF) approach. The results showed an increase of 292% in the essential work of fracture for the loading of 10 wt%. Further increasing fiber loading to 20 wt% caused the essential work of fracture to increase only 193% with respect to the unmodified material. Evaluation of the fractur... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2695285 Thu, 13 Aug 2009 12:50:14 +0100 2695285 http://www.medworm.com/index.php?rid=2648896&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F204281.html The mechanical strength and mixed mode I/II fracture toughness of hydrogen-free tetrahedral amorphous diamond-like carbon (ta-C) films, grown by pulsed laser deposition, are discussed in connection to material flaws and its microstructure. The failure properties of ta-C were obtained from films with thicknesses 0.5–3 μm and specimen widths 10–20 μm. The smallest test samples with 10 μm gage section averaged a strength of 7.3 ± 1.2 GPa, while the strength of 20-μm specimens with thicknesses 0.5–3 μm varied between 2.2–5.7 GPa. The scaling of the mechanical strength with specimen thickness and dimensions was owed to deposition-induced surface flaws, and, only in the smallest specimens,... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2648896 Wed, 29 Jul 2009 12:37:54 +0100 2648896 http://www.medworm.com/index.php?rid=2515156&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F613813.html Reversible and irreversible binding of CdSe-nanoparticles and nanorods to polymeric surfaces via a strong, multiple hydrogen bond (= Hamilton-receptor/barbituric acid) is described. Based on ROMP-copolymers, the supramolecular interaction on a thin polymer film is controlled by living polymerization methods, attaching the Hamilton-receptor in various architectures, and concentrations. Strong binding is observed with CdSe-nanoparticles and CdSe-nanorods, whose surfaces are equipped with matching barbituric acid-moieties. Addition of polar solvents, able to break the hydrogen bonds leads to the detachment of the nanoparticles from the polymeric film. Irreversible binding is observed if an azide/alkine-“click”-reaction is conducted after supramolecular recognition of the nanoparti... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2515156 Thu, 25 Jun 2009 15:15:58 +0100 2515156 http://www.medworm.com/index.php?rid=2515155&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F429867.html Carbon nanotubes (CNTs) can be understood as one or more graphite sheets rolled up into a seamless cylinder. CNTs have gained much attention and scientific interest due to their unique properties and potential applications since their discovery in 1991. In the present work, we have deposited Ni95Ti5 film using thermal deposition method. Finally, the Ni95Ti5 catalyzed multi wall carbon nanotubes (MWNTs) are grown on silicon substrate using low pressure chemical vapor deposition (LPCVD) method and the electrical transport properties of this MWNTs film are studied over a temperature range (284–4K) to explain the conduction mechanism. We have suggested two types of conduction mechanism for the entire temperature range. For the temperature region (284–220K), the conduction is due to... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2515155 Thu, 25 Jun 2009 15:15:58 +0100 2515155 http://www.medworm.com/index.php?rid=2515154&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F625047.html The potential applications of carbon nanotubes (CNT) in many engineered bionanomaterials and electromechanical devices have imposed an urgent need on the understanding of the fatigue behavior and mechanism of CNT under cyclic loading conditions. To date, however, very little work has been done in this field. This paper presents the results of a theoretical study on the behavior of CNT subject to cyclic tensile and compressive loads using quasi-static molecular simulations. The Atomistic Finite Element Method (AFEM) has been applied in the study. It is shown that CNT exhibited extreme cyclic loading resistance with yielding strain and strength becoming constant within limited number of loading cycles. Viscoelastic behavior including nonlinear elasticity, hysteresis, preconditioning (stress ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2515154 Thu, 25 Jun 2009 15:15:58 +0100 2515154 http://www.medworm.com/index.php?rid=2515153&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F479185.html In the current research work, a top-down approach was employed for the refinement of a micron scale AA2124 alloy powder 40 μm in average size using high-energy ball milling up to 60 hours. The produced nanopowders were investigated compared to the micron gas atomized powder both in the monolithic and the reinforced composite states. 1 μm powder of TiC with internal structure <100 nm was used for the reinforcement of the 2124-Al matrices. Milling time of 36 hours produced a <100 nm nanopowders with internal structure size <20 nm. The nanopowder monolithic consolidates exhibited compressive strength of 388 MPa compared to 313 MPa for micronpowder one. Addition of TiC nanostructured powder to the nanopowder consolidate... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2515153 Thu, 25 Jun 2009 15:15:58 +0100 2515153 http://www.medworm.com/index.php?rid=2468996&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2008%2F470595.html Production of NiO by chemical precipitation is the approach utilized in this work. Materials mainly used in this project are nickel nitrate hex hydrate (as a basic material), sodium hydroxide (as a precipitator material), and the following surfactants (for reduction in particle size). Applied surfactants are in two kinds: polymeric (PVP, PEG) and cationic (CTAB) surfactants, 1.0 gram. Nanopowders properties are identified by TG, FTIR, XRD, SEM, and TEM. The results obtained confirm the presence of nickel oxide nanopowders produced during chemical precipitation. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468996 Wed, 10 Jun 2009 08:21:44 +0100 2468996 http://www.medworm.com/index.php?rid=2468995&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2008%2F589532.html Secure information retrieval technology aims at status identification and documentation authentication. Ideally, materials or devices used in these technologies should be hard to find, difficult to counterfeit, and as simple as possible. This manuscript addresses a novel information retrieval technology, with photoluminescent (PL) semiconductor quantum dots (QDs) synthesized via wet chemistry approaches used as its coding materials. Conceptually, these QDs are designed to exhibit emission at Fraunhofer line positions, namely, black lines in the solar spectrum; thus, the retrieval system can extract useful information under sunshine covering areas. Furthermore, multiphoton excitation (MPE) technology enables the retrieval system to be multilayer information extraction, with thin films consi... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468995 Wed, 10 Jun 2009 08:21:44 +0100 2468995 http://www.medworm.com/index.php?rid=2468994&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F325674.html The effects of using nanosized carbon black in the range of 0–10 weight percentages on the physical and thermomechanical properties of Al2O3–SiC–SiO2–graphite refractory composites were investigated. Nanosized carbon black addition improved the relative heat resistance and oxidation resistance of composites. The bulk density of the composites is reduced with increasing carbon black (CB) content. Increase in CB content first causes an increase in the apparent porosity, but at more than 3 wt% amount of CB, a decrease of apparent porosity was observed. The cold crushing strength (CCS) increased with increasing CB content in samples fired at 800∘C and in samples fired at 1500∘C when the content is increased to 3 wt%, but the C... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468994 Wed, 10 Jun 2009 08:21:44 +0100 2468994 http://www.medworm.com/index.php?rid=2468993&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F912676.html This paper studies the structure, temperature dependences of electric resistance, and adsorption properties of nanoporous three-component V-(N, He) coatings. The coatings were produced using the technique of ion beam assisted deposition, in particular, deposition of vanadium onto a titanium substrate simultaneously bombarding it with N2+He ions of 30 keV. It is shown, in contrast to V-N composites that have negative TCR (temperature coefficient of resistance), that the V-(N, He) coatings have negative TCR only in the temperature range of 250 to 350C∘. A specific surface of pores and adsorption characteristics of V-(N, He) composites depend on preliminary treatment of a titanium surface. A coating deposited onto an untreated substrate has specific surface of 25.5 m2/g. ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468993 Wed, 10 Jun 2009 08:21:44 +0100 2468993 http://www.medworm.com/index.php?rid=2468992&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2008%2F840390.html (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468992 Wed, 10 Jun 2009 08:21:44 +0100 2468992 http://www.medworm.com/index.php?rid=2468991&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F879016.html The elaboration of bilayer TiO2/CNT films dried under terrestrial gravity conditions (g) and on a centrifuge with 1.3g and 7g is reported. The changes in microstructure and thickness of these coatings under supergravity environment cause a red-shift tendency in the optical properties at increasing values of acceleration. Experiments of a drop under enhanced gravity force in the range of 3.7 < Bo (bond number) < 51.5 suggest the incomplete elimination of surfactant-water molecules in the TiO2/CNT bilayer film. Increasing acceleration up to 14g will widen the optical differences found, proving the layer-by-layer solution-chemical method in combination with these drying protocols, an alternative to produce thickness-sensitive solar-selective absorbing coatings. (Source: Journal of Nan... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468991 Wed, 10 Jun 2009 08:21:44 +0100 2468991 http://www.medworm.com/index.php?rid=2468990&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F472950.html To enhance the electrical conductivity of the electrolyte for a newly developed dye-sensitized solar cell (DSSC), metallic copper (Cu) encapsulated within the carbon shell (Cu@C) nanoparticles dispersed in a room temperature ionic liquid (RTIL) (e.g., [bmim+][PF6−]) has been studied in the present work. By the pulsed-field gradient spin-echo NMR method, the self-diffusion coefficients of cations and anions of the RTIL have been determined. The self-diffusion coefficient of the [bmim+] cations in the RTIL dispersed with 0.08% of Cu@C nanoparticles is increased by 35%. The electrical conductivity of the Cu@C dispersed RTIL is also increased by 65% (1.0 → 2.3 ms/cm). It is very clear the nanosize Cu@C dispersed RTIL with a relati... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468990 Wed, 10 Jun 2009 08:21:44 +0100 2468990 http://www.medworm.com/index.php?rid=2468989&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F746383.html A new method for altered enamel surface remineralization has been proposed. To this aim carbonate-hydroxyapatite nanocrystals which mimic for composition, structure, nanodimensions, and morphology dentine apatite crystals and resemble closely natural apatite chemical-physical properties have been used. The results underline the differences induced by the use of fluoride ions and hydroxyapatite nanocrystals in contrasting the mechanical abrasions and acid attacks to which tooth enamel is exposed. Fluoride ions generate a surface modification of the natural enamel apatite crystals increasing their crystallinity degree and relative mechanical and acid resistance. On the other hand, the remineralization produced by carbonate-hydroxyapatite consists in a deposition of a new apatitic mineral int... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468989 Wed, 10 Jun 2009 08:21:44 +0100 2468989 http://www.medworm.com/index.php?rid=2468988&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F698501.html To enhance the efficiency of a newly developing dye-sensitized solar cell (DSSC), the Cu@C (Cu size=7 and 20 nm) core-shell nanoparticles-dispersed molten salt-conjugated electrolyte has been studied. Experimentally, the efficiencies (η) of the DSSC are in the range of 2.70–4.09% with a short-circuit photocurrent density (JSC) of 5.775–9.910 mA/cm2. Interestingly, it is found that dispersion of 1% of the Cu@C (Cu size=7 nm) nanoparticles in the molten salt-(1,2-dimethyl-3-propylimidazolium iodide (DMPII)) conjugated electrolyte results in an enhancement (about 11%) of the η (4.06%). Greater fractions (3–10%) of the Cu@C nanoparticles dispersed in the molten salt cause a poor performance (lower JSC and η) of the... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468988 Wed, 10 Jun 2009 08:21:44 +0100 2468988 http://www.medworm.com/index.php?rid=2468987&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F281721.html (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468987 Wed, 10 Jun 2009 08:21:44 +0100 2468987 http://www.medworm.com/index.php?rid=2468986&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F325769.html In this study, carbon nanofiber paper was prepared under various processing conditions, including different types of carbon nanofibers, solvents, dispersants, and acid treatment. The morphologies of carbon nanofibers within the nanofiber paper were characterized with scanning electron microscopy (SEM). In addition, the bulk densities of carbon nanofiber papers were measured. It was found that the densities and network structures of carbon nanofiber paper correlated to the dispersion quality of carbon nanofibers within the paper, which was significantly affected by papermaking process conditions. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468986 Wed, 10 Jun 2009 08:21:44 +0100 2468986 http://www.medworm.com/index.php?rid=2468985&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F762016.html Heterodyne Force Microscopy opens up a way to monitor nanoscale events with high temporal sensitivity from the quasistatic cantilever mechanical-diode response taking advantage of the beat effect. Here, a novel heterodyne ultrasonic force method is proposed, in which the cantilever is driven in amplitude-modulation mode, at its fundamental flexural eigenmode. Ultrasonic vibration in the megahertz range is additionally input at the tip-sample contact from the cantilever base and from the back of the sample. The ultrasonic frequencies are chosen in such a way that their difference is coincident with the second cantilever eigenmode. In the presence of ultrasound, cantilever vibration at the difference frequency is detected. Similarly as in heterodyne force microscopy, it is expected that the ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468985 Wed, 10 Jun 2009 08:21:44 +0100 2468985 http://www.medworm.com/index.php?rid=2468984&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F429430.html We present the fabrication and transport properties of a series of composites made of La2/3Sr1/3MnO3 and acrylamide-based copolymers. The most important result is the very narrow transition, of only 27 K, displayed by the peak that appears around the metal-insulator transition of the composites made with poly(acrylamide-vinylacetate). Although the amount of polymer is rather low, different copolymers change drastically the electric transport characteristics. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468984 Wed, 10 Jun 2009 08:21:44 +0100 2468984 http://www.medworm.com/index.php?rid=2468983&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F316035.html Sensing of ethanol with iron doped ZnO (Fe-ZnO) thin films has been studied in this work. By X-ray diffraction spectroscopy, it is found that ZnO is the main compound in the low-iron (<10%) doped ZnO thin films. ZnFe2O4 is also found as 20–50% of iron are doped on the thin films. The 5% Fe-ZnO thin film has a very high sensitivity (Rair/Rethanol>70) to 1000 ppm of ethanol at 300 K. It seems that iron can promote the sensivity of the ZnO thin film. The thin film doped with a greater amount (20–50%) of iron has, however, a much less sensitivity (<15) to ethanol. The chemical interactions between oxygen of ethanol and zinc on the Fe-ZnO thin film cause changes of the bond distances of Zn–O and Fe–O in t... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468983 Wed, 10 Jun 2009 08:21:44 +0100 2468983 http://www.medworm.com/index.php?rid=2468982&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F126354.html Zinc sulfide submicron and nanotubes with outer diameters in the range from 100 to 1000 nm were produced through chemical deposition from vapor under argon pressure. The novel process provides formation of ZnS tubes reinforced with carbon nanofibers. This is the first time that the ZnS tubes are grown with fibers during deposition. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468982 Wed, 10 Jun 2009 08:21:44 +0100 2468982 http://www.medworm.com/index.php?rid=2468981&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F936863.html We study the origin of the strong difference in the resistivity of focused-electron- and focused-Ga-ion-beam-induced deposition (FEBID and FIBID, resp.) of Pt performed in a dual beam equipment using (CH3)3Pt(CpCH3) as the precursor gas. We have performed in-situ and ex-situ resistance measurements in both types of nanodeposits, finding that the resistivity of Pt by FEBID is typically four orders of magnitude higher than Pt by FIBID. In the case of Pt by FEBID, the current-versus-voltage dependence is nonlinear and the resistance-versus-temperature behavior is strongly semiconducting, whereas Pt by FIBID shows linear current-versus-voltage dependence and only slight temperature dependence. The microstructure, as investigated by high-resolution transmission electron microscopy, consists in ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468981 Wed, 10 Jun 2009 08:21:44 +0100 2468981 http://www.medworm.com/index.php?rid=2468980&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F621208.html The molecular properties and surface morphology of undoped and N-doped ultra-nanocrystalline diamond (UNCD) films deposited by microwave plasma CVD with addition of nitrogen are investigated with various spectroscopic techniques. The results of spatially resolved Raman scattering, ATR/FT-IR and XPS spectra show more amorphous and sp2/sp3 ratio characteristics in N-doped UNCD films. The surface morphology in AFM scans shows larger nanocrystalline diamond clusters in N-doped UNCD films. Incorporation of nitrogen into UNCD films has promoted an increase of amorphous sp2-bonded carbons in the grain boundaries and the size of nanocrystalline diamond grains that are well correlated to the reported enhancement of conductivity and structural changes of UNCD films. (Source: Journal of Nanomaterials... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468980 Wed, 10 Jun 2009 08:21:44 +0100 2468980 http://www.medworm.com/index.php?rid=2468979&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F436375.html Organic nanostructures are new comers to the fields of nanoscience and nanotechnology. In recent years novel methods for controlling the growth and uniformity of one-dimensional (1D) organic nanostructures (nanowires and nanotubes) have been developing. The use of hard templates as molds for the formation of organic nanowires or nanotubes seems to be a reliable and convenient method. In this review we will discuss the use of anodic aluminum oxide (AAO) templates as the inorganic hard template of choice. We will briefly survey advances in the fabrication of 1D polymer nanostructures using AAO templates, while the bulk of the review will focus on the synthesis of small molecule nanowires, nanotubes, and nanorods. We will also discuss unique properties of some highly crystalline small molecul... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468979 Wed, 10 Jun 2009 08:21:44 +0100 2468979 http://www.medworm.com/index.php?rid=2468978&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F851290.html We have synthesized Pd-filled carbon nanotubes (CNTs) oriented perpendicular to Si substrates using a microwave plasma-enhanced chemical vapor deposition (MPECVD) for the application of scanning probe microscopy (SPM) tip. Prior to the CVD growth, Al thin film (10 nm) was coated on the substrate as a buffer layer followed by depositing a 5∼40 nm-thick Pd film as a catalyst. The diameter and areal density of CNTs grown depend largely on the initial Pd thickness. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images clearly show that Pd is successfully encapsulated into the CNTs, probably leading to higher conductivity. Using optimum growth conditions, Pd-filled CNTs are successfully grown on the apex of the conventional SPM cantilever. (So... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468978 Wed, 10 Jun 2009 08:21:44 +0100 2468978 http://www.medworm.com/index.php?rid=2468977&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F261261.html Gold nanoparticles exhibited strong surface plasmon absorption and couplings between neighboring particles within bioactivated self-assembly modified their optical properties. Colorimetric analysis on the optical modification of surface plasmon resoanance (SPR) shift and flocculation parameter functionalized bioinspired gold assembly for biophotonic application. The physical origin of bioinspired gold aggregation-induced shifting, decreasing, or broadening of the plasmon absorption spectra could be explained in terms of dynamic depolarization, collisional damping, and shadowing effects. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468977 Wed, 10 Jun 2009 08:21:44 +0100 2468977 http://www.medworm.com/index.php?rid=2468976&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F860536.html In this study, the surface of diatom frustules that possessed hierarchical architecture ordered at the micro and nanoscale was coated with a nanostructured polycrystalline cadmium sulphide (CdS) thin film using a chemical bath deposition technique. The CdS thin film was composed of spherical nanoparticles with a diameter of about 75 nm. The CdS nanoparticle thin film imparted new photoluminescent properties to the intricately patterned diatom nanostructure. The imparted photoluminescent properties were dependent on the CdS coverage onto the frustules surface. The intrinsic photoluminescent properties of the frustules were strongly quenched by the deposited CdS. The origin of PL spectra was discussed on the basis of the band theory and native defects. (Source: Journal of Nanomaterial... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468976 Wed, 10 Jun 2009 08:21:44 +0100 2468976 http://www.medworm.com/index.php?rid=2468975&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F319842.html Nanostructures of SingleCrystalSilicon (SCS) with superior electrical, mechanical, thermal, and optical properties are emerging in the development of novel nanodevices. Mechanical properties especially Young's modulus are essential in developing and utilizing such nanodevices. In this paper, experimental researches including bending tests, resonance tests, and tensile tests on Young' s modulus of nanoscaled SCS are reviewed, and their results are compared. It was found that the values of E measured by different testing methods cannot match to each other. As the differences cannot be explained as experimental errors, it should be understood by taking surface effect into account. With a simplified model, we qualitatively explained the difference in E value measured by tensile test an... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468975 Wed, 10 Jun 2009 08:21:44 +0100 2468975 http://www.medworm.com/index.php?rid=2468974&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F728957.html The most common fabrication technique of porous silicon (PS) is electrochemical etching of a crystalline silicon wafer in a hydrofluoric (HF) acid-based solution. The electrochemical process allows for precise control of the properties of PS such as thickness of the porous layer, porosity, and average pore diameter. The effect of HF concentration in the used electrolyte on physical and electronic properties of PS was studied by visual color observation, measuring nitrogen sorption isotherm, field emission type scanning electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy. It was found that with decrease in HF concentration, the pore diameter increased. The PS sample with large pore diameter, that is, smaller nanocrystalline size of Si between the pores, was found to ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468974 Wed, 10 Jun 2009 08:21:44 +0100 2468974 http://www.medworm.com/index.php?rid=2468973&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F168041.html In this study, we investigated the antibacterial properties of nano silver Poly-L-Lactic acid (Ag/PLLA) composite fibrous membranes. Ag/PLLA fibrous membranes were prepared with silver nanoparticles having weight ratio of silver nanoparticles to PLLA at 5% (w/w). In vitro antibacterial tests were performed using Escherichia coli (E. coli) and Staphylococcus aureus (Staph.) to determine the antibacterial capability of the Ag/PLLA fibrous membranes. As the results suggested, Ag/PLLA fibrous membranes showed strong antibacterial properties. Thus, Ag/PLLA fibrous membrane can be used as an antibacterial scaffold for tissue engineering. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468973 Wed, 10 Jun 2009 08:21:44 +0100 2468973 http://www.medworm.com/index.php?rid=2468972&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F302919.html ZnO-supported Pd, Pd-Ag, Pd-Cu, and Pd-Ni catalysts (Pd-M/ZnO) were prepared in MeOH/H2O mixture (4/1, v/v-%) by γ-irradiation at room temperature. Small mono- and bimetallic nanoparticles were loaded on the surface of ZnO nanopowder as confirmed with TEM, TEM-EDXS, XRD, and ICP-AES data. The catalytic efficiency against Pd-M/ZnO was determined in hydrogenation and Suzuki reaction and compared with the commercial Pd/C catalyst. The Pd-Ag/ZnO showed the highest catalytic efficiency in the Suzuki reaction. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468972 Wed, 10 Jun 2009 08:21:44 +0100 2468972 http://www.medworm.com/index.php?rid=2468971&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F562376.html We report a facile one-step approach which involves no flammable gas, no catalyst, and no in situ polymerization for the preparation of well-aligned carbon nanotube array. A polymer precursor is placed on top of an anodized aluminum oxide (AAO) membrane containing regular nanopore arrays, and slow heating under Ar flow allows the molten polymer to wet the template through adhesive force. The polymer spread into the nanopores of the template to form polymer nanotubes. Upon carbonization the resulting multi-walled carbon nanotubes duplicate the nanopores morphology precisely. The process is demonstrated for 230, 50, and 20 nm pore membranes. The synthesized carbon nanotubes are characterized with scanning/transmission electron microscopies, Raman spectroscopy, and resistive measuremen... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468971 Wed, 10 Jun 2009 08:21:44 +0100 2468971 http://www.medworm.com/index.php?rid=2468970&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F940462.html The effect of Hoffmeister anions Cl−, SO4 2-, and ClO4 - on the structure and morphology of birnessite and cryptomelane-type manganese dioxide nanostructures, produced by the reduction reaction of KMnO4 and MnSO4 in aqueous acidic media, was studied. The syntheses were based on the decomposition of aqueous KMnO4 in presence of HCl for birnessite-type and acidified MnSO4 for cryptomelane-type manganese dioxide under soft hydrothermal conditions. They were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. XRD patterns show the formation of birnessite for the first synthesis and a mixture of cryptomelane and birnessite-types MnO2 for the second synthesis. XRD ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468970 Wed, 10 Jun 2009 08:21:44 +0100 2468970 http://www.medworm.com/index.php?rid=2468969&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F498505.html A silver-hydroxyapatite nanocomposite has been obtained by a colloidal chemical route and subsequent reduction process in H2/Ar atmosphere at 350∘C. This material has been characterized by TEM, XRD, and UV-Visible spectroscopy, showing the silver nanoparticles (∼65 nm) supported onto the HA particles (∼130 nm) surface without a high degree of agglomeration. The bactericidal effect against common Gram-positive and Gram-negative bacteria has been also investigated. The results indicated a high antimicrobial activity for Staphylococcus aureus, Pneumococcus and Escherichia coli, so this material can be a promising antimicrobial biomaterial for implant and reconstructive surgery applications. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468969 Wed, 10 Jun 2009 08:21:44 +0100 2468969 http://www.medworm.com/index.php?rid=2468968&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F876561.html The atomic bonding configuration of ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) films prepared by pulsed laser ablation of graphite in a hydrogen atmosphere was examined by near-edge X-ray absorption fine structure spectroscopy. The measured spectra were decomposed with simple component spectra, and they were analyzed in detail. As compared to the a-C:H films deposited at room substrate-temperature, the UNCD/a-C:H and nonhydrogenated amorphous carbon (a-C) films deposited at a substrate-temperature of 550∘C exhibited enhanced π∗ and σ∗C≡C peaks. At the elevated substrate-temperature, the π∗ and σ∗C≡C bonds formation is enhanced while the σ∗C–H and σ∗C... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468968 Wed, 10 Jun 2009 08:21:44 +0100 2468968 http://www.medworm.com/index.php?rid=2468967&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fjnm%2F2009%2F310360.html The formation of nanoscaled one-dimensional structure constituting the thin films of ZnO via a RF magnetron sputtering process is demonstrated. A detailed analysis of these films has been carried out by exploiting the techniques of ellipsometry, scanning and transmission electron microscopy (SEM, TEM), high-resolution TEM, and scanning tunneling microscopy (STM). The importance of substrate materials due to the nanomorphologies as rods and wires on the substrates as amorphous quartz and silicon, respectively, has been elucidated. It has been exhibited that these fascinating nano-objects (rods, wires) are grown directionally along c-axis of hexagonal lattice of ZnO. The nucleation and growth mechanisms of these nano-objects have been discussed to interpret the present results. (Source: Jour... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2468967 Wed, 10 Jun 2009 08:21:44 +0100 2468967 http://www.medworm.com/index.php?rid=2463769&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F498505 A silver-hydroxyapatite nanocomposite has been obtained by a colloidal chemical route and subsequent reduction process in H2/Ar atmosphere at 350∘C. This material has been characterized by TEM, XRD, and UV-Visible spectroscopy, showing the silver nanoparticles (∼65 nm) supported onto the HA particles (∼130 nm) surface without a high degree of agglomeration. The bactericidal effect against common Gram-positive and Gram-negative bacteria has been also investigated. The results indicated a high antimicrobial activity for Staphylococcus aureus, Pneumococcus and Escherichia coli, so this material can be a promising antimicrobial biomaterial for implant and reconstructive surgery applications. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2463769 Mon, 08 Jun 2009 18:01:18 +0100 2463769 http://www.medworm.com/index.php?rid=2463768&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F876561 The atomic bonding configuration of ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) films prepared by pulsed laser ablation of graphite in a hydrogen atmosphere was examined by near-edge X-ray absorption fine structure spectroscopy. The measured spectra were decomposed with simple component spectra, and they were analyzed in detail. As compared to the a-C:H films deposited at room substrate-temperature, the UNCD/a-C:H and nonhydrogenated amorphous carbon (a-C) films deposited at a substrate-temperature of 550∘C exhibited enhanced π∗ and σ∗C≡C peaks. At the elevated substrate-temperature, the π∗ and σ∗C≡C bonds formation is enhanced while the σ∗C–H and σ∗C... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2463768 Mon, 08 Jun 2009 18:01:18 +0100 2463768 http://www.medworm.com/index.php?rid=2463767&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F310360 The formation of nanoscaled one-dimensional structure constituting the thin films of ZnO via a RF magnetron sputtering process is demonstrated. A detailed analysis of these films has been carried out by exploiting the techniques of ellipsometry, scanning and transmission electron microscopy (SEM, TEM), high-resolution TEM, and scanning tunneling microscopy (STM). The importance of substrate materials due to the nanomorphologies as rods and wires on the substrates as amorphous quartz and silicon, respectively, has been elucidated. It has been exhibited that these fascinating nano-objects (rods, wires) are grown directionally along c-axis of hexagonal lattice of ZnO. The nucleation and growth mechanisms of these nano-objects have been discussed to interpret the present results. (Source: Jour... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2463767 Mon, 08 Jun 2009 18:01:18 +0100 2463767 http://www.medworm.com/index.php?rid=2457691&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F302919 ZnO-supported Pd, Pd-Ag, Pd-Cu, and Pd-Ni catalysts (Pd-M/ZnO) were prepared in MeOH/H2O mixture (4/1, v/v-%) by γ-irradiation at room temperature. Small mono- and bimetallic nanoparticles were loaded on the surface of ZnO nanopowder as confirmed with TEM, TEM-EDXS, XRD, and ICP-AES data. The catalytic efficiency against Pd-M/ZnO was determined in hydrogenation and Suzuki reaction and compared with the commercial Pd/C catalyst. The Pd-Ag/ZnO showed the highest catalytic efficiency in the Suzuki reaction. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2457691 Sat, 06 Jun 2009 05:24:06 +0100 2457691 http://www.medworm.com/index.php?rid=2457690&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F562376 We report a facile one-step approach which involves no flammable gas, no catalyst, and no in situ polymerization for the preparation of well-aligned carbon nanotube array. A polymer precursor is placed on top of an anodized aluminum oxide (AAO) membrane containing regular nanopore arrays, and slow heating under Ar flow allows the molten polymer to wet the template through adhesive force. The polymer spread into the nanopores of the template to form polymer nanotubes. Upon carbonization the resulting multi-walled carbon nanotubes duplicate the nanopores morphology precisely. The process is demonstrated for 230, 50, and 20 nm pore membranes. The synthesized carbon nanotubes are characterized with scanning/transmission electron microscopies, Raman spectroscopy, and resistive measuremen... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2457690 Sat, 06 Jun 2009 05:24:06 +0100 2457690 http://www.medworm.com/index.php?rid=2457689&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F940462 The effect of Hoffmeister anions Cl−, SO4 2-, and ClO4 - on the structure and morphology of birnessite and cryptomelane-type manganese dioxide nanostructures, produced by the reduction reaction of KMnO4 and MnSO4 in aqueous acidic media, was studied. The syntheses were based on the decomposition of aqueous KMnO4 in presence of HCl for birnessite-type and acidified MnSO4 for cryptomelane-type manganese dioxide under soft hydrothermal conditions. They were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. XRD patterns show the formation of birnessite for the first synthesis and a mixture of cryptomelane and birnessite-types MnO2 for the second synthesis. XRD ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2457689 Sat, 06 Jun 2009 05:24:06 +0100 2457689 http://www.medworm.com/index.php?rid=2437010&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F168041 In this study, we investigated the antibacterial properties of nano silver Poly-L-Lactic acid (Ag/PLLA) composite fibrous membranes. Ag/PLLA fibrous membranes were prepared with silver nanoparticles having weight ratio of silver nanoparticles to PLLA at 5% (w/w). In vitro antibacterial tests were performed using Escherichia coli (E. coli) and Staphylococcus aureus (Staph.) to determine the antibacterial capability of the Ag/PLLA fibrous membranes. As the results suggested, Ag/PLLA fibrous membranes showed strong antibacterial properties. Thus, Ag/PLLA fibrous membrane can be used as an antibacterial scaffold for tissue engineering. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2437010 Wed, 27 May 2009 15:26:12 +0100 2437010 http://www.medworm.com/index.php?rid=2416467&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F319842 Nanostructures of SingleCrystalSilicon (SCS) with superior electrical, mechanical, thermal, and optical properties are emerging in the development of novel nanodevices. Mechanical properties especially Young's modulus are essential in developing and utilizing such nanodevices. In this paper, experimental researches including bending tests, resonance tests, and tensile tests on Young' s modulus of nanoscaled SCS are reviewed, and their results are compared. It was found that the values of E measured by different testing methods cannot match to each other. As the differences cannot be explained as experimental errors, it should be understood by taking surface effect into account. With a simplified model, we qualitatively explained the difference in E value measured by tensile test an... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2416467 Tue, 19 May 2009 03:50:22 +0100 2416467 http://www.medworm.com/index.php?rid=2416466&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F728957 The most common fabrication technique of porous silicon (PS) is electrochemical etching of a crystalline silicon wafer in a hydrofluoric (HF) acid-based solution. The electrochemical process allows for precise control of the properties of PS such as thickness of the porous layer, porosity, and average pore diameter. The effect of HF concentration in the used electrolyte on physical and electronic properties of PS was studied by visual color observation, measuring nitrogen sorption isotherm, field emission type scanning electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy. It was found that with decrease in HF concentration, the pore diameter increased. The PS sample with large pore diameter, that is, smaller nanocrystalline size of Si between the pores, was found to ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2416466 Tue, 19 May 2009 03:50:22 +0100 2416466 http://www.medworm.com/index.php?rid=2397840&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F851290 We have synthesized Pd-filled carbon nanotubes (CNTs) oriented perpendicular to Si substrates using a microwave plasma-enhanced chemical vapor deposition (MPECVD) for the application of scanning probe microscopy (SPM) tip. Prior to the CVD growth, Al thin film (10 nm) was coated on the substrate as a buffer layer followed by depositing a 5∼40 nm-thick Pd film as a catalyst. The diameter and areal density of CNTs grown depend largely on the initial Pd thickness. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images clearly show that Pd is successfully encapsulated into the CNTs, probably leading to higher conductivity. Using optimum growth conditions, Pd-filled CNTs are successfully grown on the apex of the conventional SPM cantilever. (So... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2397840 Fri, 08 May 2009 04:43:46 +0100 2397840 http://www.medworm.com/index.php?rid=2397839&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F261261 Gold nanoparticles exhibited strong surface plasmon absorption and couplings between neighboring particles within bioactivated self-assembly modified their optical properties. Colorimetric analysis on the optical modification of surface plasmon resoanance (SPR) shift and flocculation parameter functionalized bioinspired gold assembly for biophotonic application. The physical origin of bioinspired gold aggregation-induced shifting, decreasing, or broadening of the plasmon absorption spectra could be explained in terms of dynamic depolarization, collisional damping, and shadowing effects. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2397839 Fri, 08 May 2009 04:43:46 +0100 2397839 http://www.medworm.com/index.php?rid=2397838&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F860536 In this study, the surface of diatom frustules that possessed hierarchical architecture ordered at the micro and nanoscale was coated with a nanostructured polycrystalline cadmium sulphide (CdS) thin film using a chemical bath deposition technique. The CdS thin film was composed of spherical nanoparticles with a diameter of about 75 nm. The CdS nanoparticle thin film imparted new photoluminescent properties to the intricately patterned diatom nanostructure. The imparted photoluminescent properties were dependent on the CdS coverage onto the frustules surface. The intrinsic photoluminescent properties of the frustules were strongly quenched by the deposited CdS. The origin of PL spectra was discussed on the basis of the band theory and native defects. (Source: Journal of Nanomaterial... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2397838 Fri, 08 May 2009 04:43:46 +0100 2397838 http://www.medworm.com/index.php?rid=2375681&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F621208 The molecular properties and surface morphology of undoped and N-doped ultra-nanocrystalline diamond (UNCD) films deposited by microwave plasma CVD with addition of nitrogen are investigated with various spectroscopic techniques. The results of spatially resolved Raman scattering, ATR/FT-IR and XPS spectra show more amorphous and sp2/sp3 ratio characteristics in N-doped UNCD films. The surface morphology in AFM scans shows larger nanocrystalline diamond clusters in N-doped UNCD films. Incorporation of nitrogen into UNCD films has promoted an increase of amorphous sp2-bonded carbons in the grain boundaries and the size of nanocrystalline diamond grains that are well correlated to the reported enhancement of conductivity and structural changes of UNCD films. (Source: Journal of Nanomaterials... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2375681 Wed, 29 Apr 2009 18:40:29 +0100 2375681 http://www.medworm.com/index.php?rid=2375680&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F436375 Organic nanostructures are new comers to the fields of nanoscience and nanotechnology. In recent years novel methods for controlling the growth and uniformity of one-dimensional (1D) organic nanostructures (nanowires and nanotubes) have been developing. The use of hard templates as molds for the formation of organic nanowires or nanotubes seems to be a reliable and convenient method. In this review we will discuss the use of anodic aluminum oxide (AAO) templates as the inorganic hard template of choice. We will briefly survey advances in the fabrication of 1D polymer nanostructures using AAO templates, while the bulk of the review will focus on the synthesis of small molecule nanowires, nanotubes, and nanorods. We will also discuss unique properties of some highly crystalline small molecul... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2375680 Wed, 29 Apr 2009 18:40:29 +0100 2375680 http://www.medworm.com/index.php?rid=2368653&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F936863 We study the origin of the strong difference in the resistivity of focused-electron- and focused-Ga-ion-beam-induced deposition (FEBID and FIBID, resp.) of Pt performed in a dual beam equipment using (CH3)3Pt(CpCH3) as the precursor gas. We have performed in-situ and ex-situ resistance measurements in both types of nanodeposits, finding that the resistivity of Pt by FEBID is typically four orders of magnitude higher than Pt by FIBID. In the case of Pt by FEBID, the current-versus-voltage dependence is nonlinear and the resistance-versus-temperature behavior is strongly semiconducting, whereas Pt by FIBID shows linear current-versus-voltage dependence and only slight temperature dependence. The microstructure, as investigated by high-resolution transmission electron microscopy, consists in ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2368653 Mon, 27 Apr 2009 09:58:07 +0100 2368653 http://www.medworm.com/index.php?rid=2330744&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F698501 To enhance the efficiency of a newly developing dye-sensitized solar cell (DSSC), the Cu@C (Cu size=7 and 20 nm) core-shell nanoparticles-dispersed molten salt-conjugated electrolyte has been studied. Experimentally, the efficiencies (η) of the DSSC are in the range of 2.70–4.09% with a short-circuit photocurrent density (JSC) of 5.775–9.910 mA/cm2. Interestingly, it is found that dispersion of 1% of the Cu@C (Cu size=7 nm) nanoparticles in the molten salt-(1,2-dimethyl-3-propylimidazolium iodide (DMPII)) conjugated electrolyte results in an enhancement (about 11%) of the η (4.06%). Greater fractions (3–10%) of the Cu@C nanoparticles dispersed in the molten salt cause a poor performance (lower JSC and η) of the... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2330744 Fri, 17 Apr 2009 20:25:13 +0100 2330744 http://www.medworm.com/index.php?rid=2330743&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F281721 (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2330743 Fri, 17 Apr 2009 20:25:13 +0100 2330743 http://www.medworm.com/index.php?rid=2330742&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F325769 In this study, carbon nanofiber paper was prepared under various processing conditions, including different types of carbon nanofibers, solvents, dispersants, and acid treatment. The morphologies of carbon nanofibers within the nanofiber paper were characterized with scanning electron microscopy (SEM). In addition, the bulk densities of carbon nanofiber papers were measured. It was found that the densities and network structures of carbon nanofiber paper correlated to the dispersion quality of carbon nanofibers within the paper, which was significantly affected by papermaking process conditions. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2330742 Fri, 17 Apr 2009 20:25:13 +0100 2330742 http://www.medworm.com/index.php?rid=2330741&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F762016 opens up a way to monitor nanoscale events with high temporal sensitivity from the quasistatic cantilever mechanical-diode response taking advantage of the beat effect. Here, a novel heterodyne ultrasonic force method is proposed, in which the cantilever is driven in amplitude-modulation mode, at its fundamental flexural eigenmode. Ultrasonic vibration in the megahertz range is additionally input at the tip-sample contact from the cantilever base and from the back of the sample. The ultrasonic frequencies are chosen in such a way that their difference is coincident with the second cantilever eigenmode. In the presence of ultrasound, cantilever vibration at the difference frequency is detected. Similarly as in heterodyne force microscopy, it is expected that the phase response yields inform... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2330741 Fri, 17 Apr 2009 20:25:13 +0100 2330741 http://www.medworm.com/index.php?rid=2330740&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F429430 We present the fabrication and transport properties of a series of composites made of La2/3Sr1/3MnO3 and acrylamide-based copolymers. The most important result is the very narrow transition, of only 27 K, displayed by the peak that appears around the metal-insulator transition of the composites made with poly(acrylamide-vinylacetate). Although the amount of polymer is rather low, different copolymers change drastically the electric transport characteristics. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2330740 Fri, 17 Apr 2009 20:25:13 +0100 2330740 http://www.medworm.com/index.php?rid=2330739&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F316035 Sensing of ethanol with iron doped ZnO (Fe-ZnO) thin films has been studied in this work. By X-ray diffraction spectroscopy, it is found that ZnO is the main compound in the low-iron (<10%) doped ZnO thin films. ZnFe2O4 is also found as 20–50% of iron are doped on the thin films. The 5% Fe-ZnO thin film has a very high sensitivity (Rair/Rethanol>70) to 1000 ppm of ethanol at 300 K. It seems that iron can promote the sensivity of the ZnO thin film. The thin film doped with a greater amount (20–50%) of iron has, however, a much less sensitivity (<15) to ethanol. The chemical interactions between oxygen of ethanol and zinc on the Fe-ZnO thin film cause changes of the bond distances of Zn–O and Fe–O in t... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2330739 Fri, 17 Apr 2009 20:25:13 +0100 2330739 http://www.medworm.com/index.php?rid=2330738&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F126354 Zinc sulfide submicron and nanotubes with outer diameters in the range from 100 to 1000 nm were produced through chemical deposition from vapor under argon pressure. The novel process provides formation of ZnS tubes reinforced with carbon nanofibers. This is the first time that the ZnS tubes are grown with fibers during deposition. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2330738 Fri, 17 Apr 2009 20:25:13 +0100 2330738 http://www.medworm.com/index.php?rid=2301694&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F325674 The effects of using nanosized carbon black in the range of 0–10 weight percentages on the physical and thermomechanical properties of Al2O3–SiC–SiO2–graphite refractory composites were investigated. Nanosized carbon black addition improved the relative heat resistance and oxidation resistance of composites. The bulk density of the composites is reduced with increasing carbon black (CB) content. Increase in CB content first causes an increase in the apparent porosity, but at more than 3 wt% amount of CB, a decrease of apparent porosity was observed. The cold crushing strength (CCS) increased with increasing CB content in samples fired at 800∘C and in samples fired at 1500∘C when the content is increased to 3 wt%, but the C... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2301694 Sun, 05 Apr 2009 16:39:08 +0100 2301694 http://www.medworm.com/index.php?rid=2301693&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F912676 This paper studies the structure, temperature dependences of electric resistance, and adsorption properties of nanoporous three-component V-(N, He) coatings. The coatings were produced using the technique of ion beam assisted deposition, in particular, deposition of vanadium onto a titanium substrate simultaneously bombarding it with N2+He ions of 30 keV. It is shown, in contrast to V-N composites that have negative TCR (temperature coefficient of resistance), that the V-(N, He) coatings have negative TCR only in the temperature range of 250 to 350C∘. A specific surface of pores and adsorption characteristics of V-(N, He) composites depend on preliminary treatment of a titanium surface. A coating deposited onto an untreated substrate has specific surface of 25.5 m2/g. ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2301693 Sun, 05 Apr 2009 16:39:08 +0100 2301693 http://www.medworm.com/index.php?rid=2301692&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F840390 (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2301692 Sun, 05 Apr 2009 16:39:08 +0100 2301692 http://www.medworm.com/index.php?rid=2301691&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F879016 The elaboration of bilayer TiO2/CNT films dried under terrestrial gravity conditions (g) and on a centrifuge with 1.3g and 7g is reported. The changes in microstructure and thickness of these coatings under supergravity environment cause a red-shift tendency in the optical properties at increasing values of acceleration. Experiments of a drop under enhanced gravity force in the range of 3.7 < Bo (bond number) < 51.5 suggest the incomplete elimination of surfactant-water molecules in the TiO2/CNT bilayer film. Increasing acceleration up to 14g will widen the optical differences found, proving the layer-by-layer solution-chemical method in combination with these drying protocols, an alternative to produce thickness-sensitive solar-selective absorbing coatings. (Source: Journal of Nan... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2301691 Sun, 05 Apr 2009 16:39:08 +0100 2301691 http://www.medworm.com/index.php?rid=2301690&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F472950 To enhance the electrical conductivity of the electrolyte for a newly developed dye-sensitized solar cell (DSSC), metallic copper (Cu) encapsulated within the carbon shell (Cu@C) nanoparticles dispersed in a room temperature ionic liquid (RTIL) (e.g., [bmim+][PF6−]) has been studied in the present work. By the pulsed-field gradient spin-echo NMR method, the self-diffusion coefficients of cations and anions of the RTIL have been determined. The self-diffusion coefficient of the [bmim+] cations in the RTIL dispersed with 0.08% of Cu@C nanoparticles is increased by 35%. The electrical conductivity of the Cu@C dispersed RTIL is also increased by 65% (1.0 → 2.3 ms/cm). It is very clear the nanosize Cu@C dispersed RTIL with a relati... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2301690 Sun, 05 Apr 2009 16:39:08 +0100 2301690 http://www.medworm.com/index.php?rid=2301689&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F746383 A new method for altered enamel surface remineralization has been proposed. To this aim carbonate-hydroxyapatite nanocrystals which mimic for composition, structure, nanodimensions, and morphology dentine apatite crystals and resemble closely natural apatite chemical-physical properties have been used. The results underline the differences induced by the use of fluoride ions and hydroxyapatite nanocrystals in contrasting the mechanical abrasions and acid attacks to which tooth enamel is exposed. Fluoride ions generate a surface modification of the natural enamel apatite crystals increasing their crystallinity degree and relative mechanical and acid resistance. On the other hand, the remineralization produced by carbonate-hydroxyapatite consists in a deposition of a new apatitic mineral int... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2301689 Sun, 05 Apr 2009 16:39:08 +0100 2301689 http://www.medworm.com/index.php?rid=2269147&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F589532 Secure information retrieval technology aims at status identification and documentation authentication. Ideally, materials or devices used in these technologies should be hard to find, difficult to counterfeit, and as simple as possible. This manuscript addresses a novel information retrieval technology, with photoluminescent (PL) semiconductor quantum dots (QDs) synthesized via wet chemistry approaches used as its coding materials. Conceptually, these QDs are designed to exhibit emission at Fraunhofer line positions, namely, black lines in the solar spectrum; thus, the retrieval system can extract useful information under sunshine covering areas. Furthermore, multiphoton excitation (MPE) technology enables the retrieval system to be multilayer information extraction, with thin films consi... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2269147 Mon, 16 Mar 2009 22:30:25 +0100 2269147 http://www.medworm.com/index.php?rid=2261675&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F470595 Production of NiO by chemical precipitation is the approach utilized in this work. Materials mainly used in this project are nickel nitrate hex hydrate (as a basic material), sodium hydroxide (as a precipitator material), and the following surfactants (for reduction in particle size). Applied surfactants are in two kinds: polymeric (PVP, PEG) and cationic (CTAB) surfactants, 1.0 gram. Nanopowders properties are identified by TG, FTIR, XRD, SEM, and TEM. The results obtained confirm the presence of nickel oxide nanopowders produced during chemical precipitation. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2261675 Sat, 14 Mar 2009 16:30:26 +0100 2261675 http://www.medworm.com/index.php?rid=2249908&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F948183 We report here an efficient single step combined sonochemical and solvothermal synthesis process to obtain bulk quantities of nanospherical particles of cubic Mn2O3 and characterized its pseudocapacitive characteristics in relevance to electrochemical capacitors for the first time. It has been found that quantitative determination of specific capacitance yielded a value of capacitance of ∼100 Fg−1 within 0–0.4 V (versus SCE) potential range in a 6 M KOH alkaline electrolyte. The as-prepared nanopowders after being subjected to heat treatment at 400C∘ were characterized by using XRD which shows a typical cubic single-phase structure (space group Ia-3), the broad crystalline peaks indicating the presence of explicit nanostructure. Electr... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2249908 Mon, 09 Mar 2009 08:44:28 +0100 2249908 http://www.medworm.com/index.php?rid=2249907&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F612549 Direct and facile method to make carbon nanotube (CNT) tips for scanning tunneling microscopy (STM) is presented. Cobalt (Co) particles, as catalysts, are electrochemically deposited on the apex of tungsten (W) STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD). A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2249907 Mon, 09 Mar 2009 08:44:28 +0100 2249907 http://www.medworm.com/index.php?rid=2235529&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F127538 By using pure titanium powder coated with unbundled multiwall carbon nanotubes (MWCNTs) via wet process, powder metallurgy (P/M) titanium matrix composite (TMC) reinforced with the CNTs was prepared by spark plasma sintering (SPS) and subsequently hot extrusion process. The microstructure and mechanical properties of P/M pure titanium and reinforced with CNTs were evaluated. The distribution of CNTs and in situ formed titanium carbide (TiC) compounds during sintering was investigated by optical and scanning electron microscopy (SEM) equipped with EDS analyzer. The mechanical properties of TMC were significantly improved by the additive of CNTs. For example, when employing the pure titanium composite powder coated with CNTs of 0.35 mass%, the increase of tensile strength and yield s... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2235529 Thu, 05 Mar 2009 21:27:18 +0100 2235529 http://www.medworm.com/index.php?rid=2235528&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F395738 In order to explore more mechanical properties of zeolite Ferrierite (FER) single crystal, a method of determining its mechanical properties—nanoindentation reverse analysis—was obtained based on the nanoindentation experiment and numerical simulations, and this will be presented in this paper. The yield stress and the characteristic work-hardening rate were gained if its stress-strain relation was a bilinear constitutive relation. The mechanical parameters obtained by reverse analysis have been compared with ones gained by nanoindentation finite-element numerical simulations. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2235528 Thu, 05 Mar 2009 21:27:18 +0100 2235528 http://www.medworm.com/index.php?rid=2235527&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F782930 We use anodization of aluminum foil with variable applied anodization voltage to create an alumina template with bifurcated porous structures. The template is then used to electrodeposit Co, fabricating unique bifurcated Co nanowires. In order to better understand the crystal structure of our new material, we then report magnetic properties of these self-assembled bifurcated Co nanowires. Magnetic measurements of the bifurcated wires are studied as functions of branch/stem ratios, wire length, and temperature. The results are compared with those of straight Co nanowires of similar dimensions and thin film Co samples to find that a different crystal lattice structure prevails in the stems than in the branches of the wires. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2235527 Thu, 05 Mar 2009 21:27:18 +0100 2235527 http://www.medworm.com/index.php?rid=2218458&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F795928 NiO nanoparticles with average particle size of 25 nm were successfully prepared by anodic arc plasma method. The composition, morphology, crystal microstructure, specific surface area, infrared spectra, and particle size distribution of product were analyzed by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED), Fourier transform infrared (FTIR) spectrum, and Brunauer-Emmett-Teller (BET) N2 adsorption. The experiment results show that the NiO nanoparticles are bcc structure with spherical shape and well dispersed, the particle size distribution ranging from 15 to 45 nm with the average particle size is about 25 nm, and the specific surface area is 33 m2/g. The infrared a... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2218458 Fri, 27 Feb 2009 08:52:56 +0100 2218458 http://www.medworm.com/index.php?rid=2192365&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F921654 Magnetic nanoparticles (NPs) of cobalt ferrite have been synthesized via a homogeneous precipitation route using hexamethylenetetramine (HMT) as the precipitant. The particle size, crystal structure, and magnetic properties of the synthesized particles were investigated by X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The NPs are of cubic inverse spinel structure and nearly spherical shape. With the increase of oxidation time from 30 to 180 minutes in the reaction solution at 90∘C, the average particle size increases from ~30 nm to ~45 nm. The as-synthesized NPs ~30 nm in size show higher Ms (61.5 emu/g) and moderate Hc (945 Oe) and Mr/Ms (0.45) value compared with the materials synthes... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2192365 Wed, 18 Feb 2009 04:48:09 +0100 2192365 http://www.medworm.com/index.php?rid=2168904&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F968058 In the protecting inert gas, silver nanoparticles were successfully prepared by confined arc plasma method. The particle size, microstructure, and morphology of the particles by this process were characterized via X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED). The N2 absorption-desorption isotherms of the samples were measured by using the static volumetric absorption analyzer, the pore structure of the sample was calculated by Barrett-Joyner-Halenda (BJH) academic model, and the specific surface area was calculated from Brunauer-Emmett-Teller (BET) adsorption equation. The experiment results indicate that the crystal structure of the samples is face-centered cubic (FCC) structure the same as the bulk ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2168904 Mon, 09 Feb 2009 03:55:50 +0100 2168904 http://www.medworm.com/index.php?rid=2151061&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F638523 ZnO nanowire arrays were grown on a Si (100) substrate using the vapor-liquid-solid (VLS) method. ZnO nanowires were characterized by XRD, SEM, bright field TEM, and EDS. They were found to have a preferential orientation along the c-axis. The as-prepared sample was functionalized with glucose oxidase by physical adsorption. FTIR was taken before and after functionalization to verify the presence of the attached enzyme. Electrochemical measurements were performed on the nanowire array by differential pulse voltammetry in the range of −0.6 to 0.4 V. The nanoarray sensor displayed high sensitivity to glucose in the range of 1.0 ×10−4 to 1.0 ×10−2 mol L−1. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2151061 Mon, 02 Feb 2009 18:43:10 +0100 2151061 http://www.medworm.com/index.php?rid=2117295&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F946038 A special cellular automaton (CA) model called mechanical cellular automaton (MCA) is built, in which inhomogeneity of material cell can be evaluated by Weibull's distribution function. In MCA, such material physical parameters as energy or strength and anisotropy defined by the different transferring energies along different directions are adopted. To simulate a crack or a weak zone, a cluster of weak energy cells are disposed. By the MCA, examples of failure evolving process of material containing one crack, two parallel cracks, and two cracks by bridge conjunction are simulated. The results show for inhomogeneous materials that their failure behaviors are much different from homogeneous ones, self-organization must be considered, and traditional homogeneous mechanics cannot be applied b... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2117295 Wed, 21 Jan 2009 10:20:02 +0100 2117295 http://www.medworm.com/index.php?rid=2113844&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F606283 An efficient approach for the preparation of good-quality boron nitride nanotubes (BNNTs) is developed. BNNTs with specific texture were prepared from ammonia borane (BH3NH3) by vapor-phase pyrolysis with the aid of a template in two independent temperature-controlled furnaces. Two kinds of BNNTs, 200–300 nm wide ×60 μm long and 70–80 nm wide ×40 μm long, were produced after removal of the templates. The as-produced BNNTs were heated at different temperatures in the range of 1300–1700C∘ in NH3. FT-IR and XPS results confirmed the formation of BN from BH3NH3. Ordered arrays of BNNTs without cracks on the surface were seen using microstructural observations. The diameter and length of the BNNTs are controlled us... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2113844 Mon, 19 Jan 2009 14:03:48 +0100 2113844 http://www.medworm.com/index.php?rid=2098643&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F834248 The present work studies the effects of the diameter of carbon nanotube (CNT) as well as CNT weight fraction on the uniaxial stress-strain behavior, stiffness, and strength of CNT-reinforced epoxy-matrix composites. The experimental results show that average Young's moduli of 5 wt%-CNT/epoxy composites with a CNT diameter D<20 nm and D=40∼60 nm are 4.56 GPa and 4.36 GPa, and the average tensile strengths are 52.89 MPa and 46.80 MPa, respectively, which corresponds to a percentage increase of 61.1%, 54.1%, 106%, and 82.3%, respectively. Two micromechanics models are employed and the predicted Young's moduli are benchmarked with the experimental data of MWCNT-reinforced epoxy-matrix composites. (Source... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2098643 Tue, 13 Jan 2009 14:47:06 +0100 2098643 http://www.medworm.com/index.php?rid=2098642&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F515890 Films of bamboo-like carbon nanotubes (BCNTs) were grown directly on copper substrates by sulfur-assisted hot filament chemical vapor deposition (HFCVD). The effects of substrate temperature and growth time over the BCNT structure were investigated. The films were characterized by scanning electron microscopy (SEM), Raman spectroscopy (RS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electron field emission (EFE) studies. SEM and Raman characterization indicate a transition from the growth of microcrystalline diamond to the growth of a dense entangled network of carbon nanotubes or fibers as the substrate temperature is increased from 400 to 900∘C that is accounted for by the base growth model. TEM images show that the nanotubes have regular a... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2098642 Tue, 13 Jan 2009 14:47:06 +0100 2098642 http://www.medworm.com/index.php?rid=2079062&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F826974 Supercritical antisolvent precipitation is a relatively recent technology which can be used for controlled preparation of polymer particles from solutions. This is done by the addition of an antisolvent to a polymer solution causing supersaturation of the polymer, especially under supercritical conditions. The particle size of the precipitates can be adjusted mainly by the rate of supersaturation. Spherical xylan or mannan particles having a narrow particle size distribution were precipitated from hemicellulose solutions in dimethyl-sulfoxide (DMSO) or DMSO/water mixtures by carbon dioxide as an antisolvent. By depending on the type of hemicellulose, the DMSO/H2O ratio, and the precipitation conditions such as pressure and temperature, the resulting particle size can be adjusted within a w... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2079062 Mon, 05 Jan 2009 13:03:14 +0100 2079062 http://www.medworm.com/index.php?rid=2078413&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F620269 Asymmetric inorganic/organic composite nanoparticles with anisotropic surface functionalities represent a new approach for creating smart materials, requiring the selective introduction of chemical groups to dual components of composite, respectively. Here, we report the synthesis of snowman-like asymmetric silica/polystyrene heterostructure with anisotropic functionalities via a chemical method, creating nanostructure possibly offering two-sided biologic accessibility through the chemical groups. Carboxyl group was introduced to polystyrene component of the snowman-like composites by miniemulsion polymerization of monomer on local surface of silica particles. Moreover, amino group was then grafted to remained silica surface through facile surface modification of the composite nanoparticle... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2078413 Sun, 04 Jan 2009 16:10:41 +0100 2078413 http://www.medworm.com/index.php?rid=2078412&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F901241 Optical emission spectroscopy was used to study pulsed laser ablation of graphite in a hydrogen atmosphere wherein ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite films were grown on heated substrates. Time-resolved photographs of a plume that expanded from a laser-irradiation spot toward a substrate were taken using a high-speed ICCD camera equipped with narrow-bandpass filters. While the emissions from C atoms and C2 dimers lasted above the laser-irradiation spot on the target, the emission from C+ ions lasted above the substrate surface for approximately 7 microseconds, although the emission lifetime of species is generally approximately 10 nanoseconds. This implies that C+ ions actively collided with each other above the substrate surface for such a ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2078412 Sun, 04 Jan 2009 16:10:41 +0100 2078412 http://www.medworm.com/index.php?rid=2076824&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F481270 Cross-linked assemblies of nanoparticles are of great value as chemiresistor-type sensors. Herein, we report a simple method to fabricate a chemiresistor-type sensor that minimizes the swelling transduction mechanism while optimizing the change in dielectric response. Sensors prepared with this methodology showed enhanced chemoselectivity for phosphonates which are useful surrogates for chemical weapons. Chemoselective sensors were fabricated using an aqueous solution of gold nanoparticles that were then cross-linked in the presence of the silica precursor, tetraethyl orthosilicate with the α-, ω-dithiolate (which is derived from the in situ deprotection of 1,4-di(Phenylethynyl-4′,4″-diacetylthio)-benzene (1) with wet triethylamine). The cross-linked nanoparti... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2076824 Sat, 03 Jan 2009 20:17:28 +0100 2076824 http://www.medworm.com/index.php?rid=2063071&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F832327 Carbon-based electronic materials have received much attention since the discovery and elucidation of the properties of the nanotube, fullerene allotropes, and conducting polymers. Amorphous carbon, graphite, graphene, and diamond have also been the topics of intensive research. In accordance with this interest, we herein provide the details of a novel and facile method for synthesis of poly(hydridocarbyne) (PHC), a preceramic carbon polymer reported to undergo a conversion to diamond-like carbon (DLC) upon pyrolysis and also provide electrical characterization after low-temperature processing and pyrolysis of this material. The results indicate that the strongly insulating polymer becomes notably conductive in bulk form upon heating and contains interspersed micro- and nanostructures, whi... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2063071 Wed, 24 Dec 2008 20:29:21 +0100 2063071 http://www.medworm.com/index.php?rid=2056679&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F763706 A new method for preparing black birnessite nanoparticles is introduced. The initial synthesis process resembles the classical McKenzie method of preparing brown birnessite except for slower cooling and closing the system from the ambient air. Subsequent process, including wet-aging at 7∘C for 48 hours, overnight freezing, and lyophilization, is shown to convert the brown birnessite into black birnessite with complex nanomorphology with folded sheets and spirals. Characterization of the product is performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), and N2 adsorption (BET) techniques. Wet-aging and lyophilization times are shown to affect the architecture of the produ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2056679 Mon, 22 Dec 2008 16:18:17 +0100 2056679 http://www.medworm.com/index.php?rid=2056678&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F642036 Polymethyl methacrylate (PMMA)-BN nanotube (BNNT) composites were fabricated and their mechanical and thermal properties were analyzed. Using a 1 wt.% BNNTs fraction in a polymer, the elastic modulus of PMMA was increased up to 19%. In addition, thermal stability and glass transition temperature of PMMA were also positively affected. The thermal conductivity of PMMA with BNNT additions increased three times. The resultant BNNT-PMMA composites possess the high electrical breakover voltages. Thus our studies clearly indicate that BNNTs are promising nanofillers for improvement of mechanical and thermal conductivity of dielectric polymers under preservation of their electrical insulation. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2056678 Mon, 22 Dec 2008 16:18:17 +0100 2056678 http://www.medworm.com/index.php?rid=2042575&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F538421 The degree of intercalation of the polyvinyl alcohol-starch blend with the layered silicate is increased if the silicates is untreated or intercalated with ammonium ions that contain small radicals. If untreated silicate like NaMMT is used, it is possible to obtain exfoliated-intercalated nanocomposites. The materials based on PVOH, starch, and Nanocor I 28, Nanocor I 33, or Cloisite 15 A can be intercalated nanocomposites. If the blend of PVOH and starch is reinforced with Cloisite 93 A, microcomposites can result. The study will continue with the analysis of the new morphologies considering the transmission electron microscopy (TEM). (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2042575 Wed, 17 Dec 2008 20:22:04 +0100 2042575 http://www.medworm.com/index.php?rid=2042574&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F950967 Nanomaterials have attracted great interest in recent years because of the unusual mechanical, electrical, electronic, optical, magnetic and surface properties. The high surface/volume ratio of these materials has significant implications with respect to energy storage. Both the high surface area and the opportunity for nanomaterial consolidation are key attributes of this new class of materials for hydrogen storage devices. Nanostructured systems including carbon nanotubes, nano-magnesium based hydrides, complex hydride/carbon nanocomposites, boron nitride nanotubes, TiS2/MoS2 nanotubes, alanates, polymer nanocomposites, and metal organic frameworks are considered to be potential candidates for storing large quantities of hydrogen. Recent investigations have shown that nanoscale materials... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2042574 Wed, 17 Dec 2008 20:22:04 +0100 2042574 http://www.medworm.com/index.php?rid=2029433&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F340217 Using the prepared Fe3O4 particles of 10 nm–25 nm as magnetic core, we synthesized Fe3O4/MnO2 composite particles with MnO2 as the shell by homogeneous precipitation. Their structure and morphology were characterized by X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), transmission electronic microscopy (TEM), Fourier transform infrared spectra (FTIR), and vibration-sample magnetometer (VSM). We show that with urea as precipitant transparent and uniform MnO2 coating of ca.3 nm thick on Fe3O4, particles can be obtained. The composite particles have better dispersivity than the starting materials, and exhibit super-paramagnetic properties and better chemical adsorption ability with saturated magnetization of 33.5 emu/g. Decoloration experiment... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2029433 Thu, 11 Dec 2008 18:38:35 +0100 2029433 http://www.medworm.com/index.php?rid=2029432&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F147204 Carbon nanotubes (CNTs) have been successfully grown on the tip apex of an atomic force microscopy (AFM) cantilever by microwave plasma-enhanced chemical vapor deposition (MPECVD). Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal that the diameter of the CNTs is ∼30 nm and the magnetic particles with diameter of ∼20 nm, which was used as catalyst for the CNT growth, exist on the top. This CNT probe has been applied to magnetic force microscopy (MFM) on the ultrahigh-density magnetic recording media with 1200 kilo flux change per inch (kfci). (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2029432 Thu, 11 Dec 2008 18:38:35 +0100 2029432 http://www.medworm.com/index.php?rid=2029431&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F136856 Polyamide 66 (PA66)/Brazilian clay nanocomposites were produced via direct melt intercalation. A montmorillonite sample from the Brazilian state of Paraíba was organically modified with esthearildimethylammonium chloride (Praepagen), quaternary ammonium salt and has been tested to be used in polymer nanocomposites. The dispersion analysis and the interlayer spacing of the clay particles in matrix were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal behavior of the obtained systems was investigated by differential scanning calorimetry (DSC), thermogravimetry (TG), and heat deflection temperature (HDT) was reported too. The nanocomposites exhibited a partially exfoliated structure, very interesting HDT values which are higher than those of pur... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2029431 Thu, 11 Dec 2008 18:38:35 +0100 2029431 http://www.medworm.com/index.php?rid=2019158&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F957935 We report the results of the ambient pressure synthesis of tungsten oxide nanowires and nanoparticles on AlN substrates using the hot filament CVD techniques. The morphologic surface, crystallographic structures, chemical compositions, and bond structures of the obtained samples have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and Raman scattering, respectively. Different morphologies were observed for different substrate temperatures, but otherwise identical growth conditions. The experimental measurements reveal the evolutions of the crystalline states and bond structures following the substrate temperatures. Besides, different substrate materials also affected the tungsten oxide nanostructures. Bundles ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2019158 Sun, 07 Dec 2008 17:46:12 +0100 2019158 http://www.medworm.com/index.php?rid=2019157&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F429168 This paper proposed a novel design of microgyroscope based on MEMS structures and optic interferometric microdisplacement measurement technique. The gyroscope consists of microvibrator and interferometric readout. Using Coriolis force, the vibrator transfers the system rotation into a forced vibration; the induced vibration can be sensed by the interferometric microdisplacement measurement system. The optic measurement system has two mirrors which will reflect two rays into a detector. The comprehensive studies on the formulation and analysis of the proposed gyroscope have been undertaken; two key sensor equations have been derived in the first time in the world: (1) relation between rotation and phase shift of light Δφ=(4πl0/λ)+(8π/λ)(xmax⁡... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=2019157 Sun, 07 Dec 2008 17:46:12 +0100 2019157 http://www.medworm.com/index.php?rid=1999700&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2009%2F245941 We investigate the compressive yielding of Ni single crystals by performing atomistic simulations with the sample diameters in the range of 5 nm ∼ 40 nm. Remarkable effects of sample sizes on the yield strength are observed in the nanopillars with two different orientations. The deformation mechanisms are characterized by massive dislocation activities within a single slip system and a nanoscale deformation twining in an octal slip system. A dislocation dynamics-based model is proposed to interpret the size and temperature effects in single slip-oriented nanopillars by considering the nucleation of incipient dislocations. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1999700 Mon, 01 Dec 2008 15:39:45 +0100 1999700 http://www.medworm.com/index.php?rid=1985756&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F529890 (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1985756 Tue, 25 Nov 2008 16:36:04 +0100 1985756 http://www.medworm.com/index.php?rid=1985755&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F395490 Swift heavy ion irradiation is an effective technique to induce changes in the microstructure and electronic energy levels of materials leading to significant modification of properties. Here we report enhancement of ammonia (NH3) sensitivity of SnO2 thin films subjected to high-energy Ni+ ion irradiation. Sol-gel-derived SnO2 thin films (100 nm thickness) were exposed to 75 MeV Ni+ ion irradiation, and the gas response characteristics of irradiated films were studied as a function of ion fluence. The irradiated films showed p-type conductivity with a much higher response to NH3 compared to other gases such as ethanol. The observed enhancement of NH3 sensitivity is discussed in context of ion beam generated electronic states in the SnO2 thin films. (Source: Journal of Nanomat... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1985755 Tue, 25 Nov 2008 16:36:04 +0100 1985755 http://www.medworm.com/index.php?rid=1982120&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F271631 An amorphous shell/nanocrystalline core nanostructured TiO2 electrode was prepared at low temperature, in which the mixture of TiO2 powder and TiCl4 aqueous solution was used as the paste for coating a film and in this film amorphous TiO2 resulted from direct hydrolysis of TiCl4 at 100∘C sintering was produced to connect the particles forming a thick crack-free uniform nanostructured TiO2 film (12 μm), and on which a photoelectrochemical solar cell-based was fabricated, generating a short-circuit photocurrent density of 13.58 mA/cm2, an open-circuit voltage of 0.647 V, and an overall 4.48% light-to-electricity conversion efficiency under 1 sun illumination. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1982120 Sun, 23 Nov 2008 16:19:59 +0100 1982120 http://www.medworm.com/index.php?rid=1948425&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F649130 For the first time copper 3-(6-mercaptohexyl)thiophene-protected nanoparticles (Cu T6SH) have been synthesized by a one-phase system, utilizing an NaBH4/LiCl mixture in diglyme as the reducing reagent and avoiding water medium dissolving copper salts. The prepared nanoclusters, characterized by transmission electron microscopy (TEM), have shown a constant spherical morphology with a size dimension of 5-6 nm in diameter. After their synthesis, no morphological evolution and irreversible aggregation process has been observed after a storage in CH2Cl2 at low temperature for a period up to six months long. Cu T6SH nanoparticles have been investigated by UV-Visible (UV-Vis) and Fourier transmission infrared (FTIR) spectroscopes to characterize the alkylthiophenes monolayer conformations ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1948425 Tue, 11 Nov 2008 15:37:57 +0100 1948425 http://www.medworm.com/index.php?rid=1948424&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F964046 Fluorinated hybrid organic-inorganic silicates (ORMOSIL) thin films display exceptional mechanical properties in terms of both hardness and elastic modulus that can be finely tuned by varying the angular velocity of the spin coating process. Hence, as traditional alkyl-modified silica xerogels generally show poor mechanical behavior, these materials offer a solution to a major limitation to applicability of ORMOSIL-based films. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1948424 Tue, 11 Nov 2008 15:37:57 +0100 1948424 http://www.medworm.com/index.php?rid=1948423&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F329601 New types of thermoelectric materials characterized by highly anisotropic Fermi surfaces and thus anisotropic Seebeck coefficients are reviewed. Early studies revealed that there is an induced voltage in high TC oxide superconductors when the surface of the films is exposed to short light pulses. Subsequent investigations proved that the effect is due to anisotropic components of the Seebeck tensor, and the type of materials is referred to atomic layer thermopile (ALT). Our recent studies indicate that multilayer thin films at the nanoscale demonstrate enhanced ALT properties. This is in agreement with the prediction in seeking the larger figure of merit (ZT) thermoelectric materials in nanostructures. The study of ALT materials provides both deep insight of anisotropic transport property ... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1948423 Tue, 11 Nov 2008 15:37:57 +0100 1948423 http://www.medworm.com/index.php?rid=1931309&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F106970 The research on the development of new biomaterials that promote bone tissue regeneration is receiving great interest by the biomedical scientific community. Recent advances in nanotechnology have allowed the design of materials with nanostructure similar to that of natural bone. These materials can promote new bone formation by inducing the formation of nanocrystalline apatites analogous to the mineral phase of natural bone onto their surfaces, i.e. they are bioactive. They also stimulate osteoblast proliferation and differentiation and, therefore, accelerate the healing processes. Silica-based ordered mesoporous materials are excellent candidates to be used as third generation bioceramics that enable the adsorption and local control release of biological active agents that promote bone r... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1931309 Tue, 04 Nov 2008 19:43:47 +0100 1931309 http://www.medworm.com/index.php?rid=1915745&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F869354 Nanocomposites based on segmented poly(urethane urea) were prepared by reacting a poly(diisocyanate) with diamine-modified Laponite-RD nanoparticles that served as a chain extender. The nanocomposites were prepared at a constant NH2 to NCO mole ratio of 0.95, while varying the fraction of diamine-modified Laponite relative to the free diamine chain extender. Compared to neat poly(urethane urea), all nanocomposites showed increased tensile strength and elongation at break. As Laponite loading increased, tensile properties passed through a maximum at a particle concentration of 1 mass%, at which a 300% increase in tensile strength and 40% increase in elongation at break were observed. A maximum in urea and urethane hard-domain melting endotherms was also observed at this Laponite... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1915745 Wed, 29 Oct 2008 18:44:18 +0100 1915745 http://www.medworm.com/index.php?rid=1915744&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F783981 A wet-mechanochemical reaction for surface modification of multiwalled carbon nanotubes (CNTs) has been developed. In the treatment, CNTs reacted with potassium hydroxide in alcohol solvent at room temperature under mechanical milling. The results from Fourier transmission infrared spectroscopy demonstrate that the nonreactive surfaces of CNTs have been modified successfully by multiple hydroxyl groups. Functionalized carbon nanotubes exhibit higher zeta potential values indicating their high dispersibility in polar solvents. XRD studies corroborate that the surface functionalization does not affect the basic crystal domain size of CNTs. TEM observations reveal that CNTs have been cut into shorter ones by the milling. Shortened CNTs with functionalized surfaces show good dispersion propert... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1915744 Wed, 29 Oct 2008 18:44:18 +0100 1915744 http://www.medworm.com/index.php?rid=1908089&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F425195 Multiwalled carbon nanotubes (MWCNTs) were synthesized by CVD on industrially manufactured highly crystalline vapor-grown carbon fibers (VGCFs). Two catalyst metals (Ni and Fe) and carbon precursor gases (C2H2 and CO) were studied. The catalysts were deposited on the fibers by sputtering and experiments carried out in two different reactors. Samples were characterized by electron microscopy (SEM and TEM). Iron was completely inactive as catalyst with both C2H2 and CO for reasons discussed in the paper. The combination of Ni and C2H2 was very active for secondary CNT synthesis, without any pretreatment of the fibers. The optimal temperature for CNT synthesis was 750∘C, with total gas flow of 650 cm3min⁡−1 of C2H2, H2, and Ar in 1.0:6.7:30 ratio. (Source: Journal... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1908089 Sun, 26 Oct 2008 15:01:17 +0100 1908089 http://www.medworm.com/index.php?rid=1892565&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F243792 A bottom-up methodology to fabricate a nanostructured material by Au nanoclusters on 6H-SiC surface is illustrated. Furthermore, a methodology to control its structural properties by thermal-induced self-organization of the Au nanoclusters is demonstrated. To this aim, the self-organization kinetic mechanisms of Au nanoclusters on SiC surface were experimentally studied by scanning electron microscopy, atomic force microscopy, Rutherford backscattering spectrometry and theoretically modelled by a ripening process. The fabricated nanostructured materials were used to probe, by local conductive atomic force microscopy analyses, the electrical properties of nano-Schottky contact Au nanocluster/SiC. Strong efforts were dedicated to correlate the structural and electrical characteristics: the m... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1892565 Tue, 21 Oct 2008 18:59:48 +0100 1892565 http://www.medworm.com/index.php?rid=1889286&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F769250 We report the salient features of the mobility and saturation velocity controlling the charge transport in a semiconducting single-walled CNT (SWCNT) channel. The ultimate drift velocity in SWCNT due to the high-electric-field streaming is based on the asymmetrical distribution function that converts randomness in zero-field to a stream-lined one in a very high electric field. Specifically, we show that a higher mobility in an SWCNT does not necessarily lead to a higher saturation velocity that is limited by the mean intrinsic velocity depending upon the band parameters. The intrinsic velocity is found to be appropriate thermal velocity in the nondegenerate regime, increasing with the temperature, but independent of carrier concentration. However, this intrinsic velocity is the Fermi veloc... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1889286 Mon, 20 Oct 2008 17:31:07 +0100 1889286 http://www.medworm.com/index.php?rid=1889285&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F354258 BaCe0.9−xZrxY0.1O3−δ powders were synthesized by a solid-state reaction. Different contents of cerium and zirconium were studied. Pellets were sintered using either conventional sintering in air at 1700∘C or the Spark Plasma Sintering (SPS) technique. The density of the samples sintered by SPS is much higher than by conventional sintering. Higher values of ionic conductivity were obtained for the SPS sample. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1889285 Mon, 20 Oct 2008 17:31:07 +0100 1889285 http://www.medworm.com/index.php?rid=1871444&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F931380 (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1871444 Mon, 13 Oct 2008 17:27:23 +0100 1871444 http://www.medworm.com/index.php?rid=1863721&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F282187 Two kinds of β-SiAlON nanostructure whiskers, rod-like and wool-like whiskers, were synthesized by pressure-less sintering method at 1773 K for 5 hours. The whiskers synthesized were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and high-resolution electron microscope (HREM) techniques. It was found that diameter distribution of rod-like whiskers was about 80–250 nm, while it was about 45–55 nm in diameter for the wool-like whiskers. The growth mechanisms of β-SiAlON nanostructure whiskers are discussed by the vapor-solid (VS) and vapor-liquid-solid (VLS) mechanisms, respectively. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1863721 Thu, 09 Oct 2008 20:30:56 +0100 1863721 http://www.medworm.com/index.php?rid=1838527&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F194524 We performed preliminary experiments on the adhesion of a Tokay gecko on surfaces with different roughness, with or without particles with significant different granulometry, before/after or during the moult. The results were analyzed using the Weibull statistics. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1838527 Tue, 30 Sep 2008 19:07:47 +0100 1838527 http://www.medworm.com/index.php?rid=1834927&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F408606 (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1834927 Sun, 28 Sep 2008 20:35:49 +0100 1834927 http://www.medworm.com/index.php?rid=1834926&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F609184 Core-shell hybrid nanoparticles, where the core is an inorganic nanoparticle and the shell an organic polymer, are prepared by a two-step method. Inorganic nanoparticles are first dispersed in water using poly(acrylic acid) (PAA) prepared by reversible addition fragmentation chain transfer (RAFT) polymerization as dispersant. Then, the resulting dispersion is engaged in a radical emulsion polymerization process whereby a hydrophobic organic monomer (styrene and butyl acrylate) is polymerized to form the shell of the hybrid nanoparticle. This method is extremely versatile, allowing the preparation of a variety of nanocomposites with metal oxides (alumina, rutile, anatase, barium titanate, zirconia, copper oxide), metals (Mo, Zn), and even inorganic nitrides (Si3N4). (Source: Journal of Nano... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1834926 Sun, 28 Sep 2008 20:35:49 +0100 1834926 http://www.medworm.com/index.php?rid=1834925&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F249514 The time-resolved two-photon photoemission technique (TR-2PPE) has been applied to study static and dynamic properties of localized surface plasmons (LSP) in silver nanoparticles. Laterally, integrated measurements show the difference between LSP excitation and nonresonant single electron-hole pair creation. Studies below the optical diffraction limit were performed with the detection method of time-resolved photoemission electron microscopy (TR-PEEM). This microscopy technique with a resolution down to 40 nm enables a systematic study of retardation effects across single nanoparticles. In addition, as will be shown in this paper, it is a highly sensitive sensor for coupling effects between nanoparticles. (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1834925 Sun, 28 Sep 2008 20:35:49 +0100 1834925 http://www.medworm.com/index.php?rid=1827159&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F620412 Colloidal solid-solution-like Au-Ag alloy nanoclusters of different compositions were synthesized through citrate reduction of mixed metal ions of low concentrations, without using any other protective or capping agents. Optical absorption of the alloy nanoclusters was studied both theoretically and experimentally. The position of the surface plasmon resonance (SPR) absorption band of the nanoclusters could be tuned from 419 nm to 521 nm through the variation of their composition. Considering effective dielectric constant of the alloy, optical absorption spectra for the nanoclusters were calculated using Mie theory, and compared with the experimentally obtained spectra. Theoretically obtained optical spectra well resembled the experimental spectra when the true size distrib... Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1827159 Thu, 25 Sep 2008 18:27:47 +0100 1827159 http://www.medworm.com/index.php?rid=1811668&cid=s_37732_173_f&fid=37732&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F408606 (Source: Journal of Nanomaterials) Journal of Nanomaterials journals http://www.medworm.com/rss/comments.php?id=1811668 Sun, 21 Sep 2008 17:50:41 +0100 1811668