MedWorm: Physics

Hyperfine spectroscopy of the 1s2p transition of Ar

Review of Scientific Instruments — Fri, 20 Nov 2009 16:11:34 +0100

We report on the first experimental determination of the hyperfine structure of the 1s2p transition in Ar. We give a detailed description of the sample preparation, spectroscopy cell cleaning, and spectroscopic setup. The resulting set of parameters consists of the hyperfine constants of the levels ... [Rev. Sci. Instrum. 80, 113109 (2009)] published Thu Nov 19, 2009. (Source: Review of Scientific Instruments)

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Dressed soliton in quantum dusty pair-ion plasma

Physics of Plasmas — Fri, 20 Nov 2009 16:11:34 +0100

Prasanta Chatterjee, Kaushik Roy, S. V. Muniandy, and C. S. Wong Nonlinear propagation of a quantum ion-acoustic dressed soliton is studied in a dusty pair-ion plasma. The Kortewegde Vries (KdV) equation is derived using reductive perturbation technique. A higher order inhomogeneous differential equation is obtained for the higher order correction. The expression ... [Phys. Plasmas 16, 112106 (2009)] published Thu Nov 19, 2009. (Source: Physics of Plasmas)

Parametric analysis of a magnetized cylindrical plasma

Physics of Plasmas — Fri, 20 Nov 2009 16:11:34 +0100

Eduardo Ahedo The relevant macroscopic model, the spatial structure, and the parametric regimes of a low-pressure plasma confined by a cylinder and an axial magnetic field is discussed for the small-Debye length limit, making use of asymptotic techniques. The plasma response is fully characterized by three-dimens ... [Phys. Plasmas 16, 113503 (2009)] published Thu Nov 19, 2009. (Source: Physics of Plasmas)

Stochastic analysis of pitch angle scattering of charged particles by transverse magnetic waves

Physics of Plasmas — Fri, 20 Nov 2009 16:11:34 +0100

Don S. Lemons, Kaijun Liu, Dan Winske, and S. Peter Gary This paper describes a theory of the velocity space scattering of charged particles in a static magnetic field composed of a uniform background field and a sum of transverse, circularly polarized, magnetic waves. When that sum has many terms the autocorrelation time required for particle orbits to b ... [Phys. Plasmas 16, 112306 (2009)] published Thu Nov 19, 2009. (Source: Physics of Plasmas)

Guiding of 35 TW laser pulses in ablative capillary discharge waveguides

Physics of Plasmas — Fri, 20 Nov 2009 16:11:34 +0100

C. McGuffey, M. Levin, T. Matsuoka, V. Chvykov, G. Kalintchenko et al. An ablatively driven capillary discharge plasma waveguide has been used to demonstrate guiding of 30 fs, 35 TW laser pulses over distances up to 3 cm with incident intensity in excess of 4 x 10 W/cm. The plasma density range over which good guiding was observed was 13 x 10 cm. The quality of the l ... [Phys. Plasmas 16, 113105 (2009)] published Thu Nov 19, 2009. (Source: Physics of Plasmas)

Numerical simulation of liquid sloshing in a partially filled container with inclusion of compressibility effects

Physics of Fluids — Fri, 20 Nov 2009 16:11:33 +0100

Y. G. Chen and W. G. Price A numerical scheme of study is developed to model compressible two-fluid flows simulating liquid sloshing in a partially filled tank. For a two-fluid system separated by an interface as in the case of sloshing, not only a Mach-uniform scheme is required but also an effective way to eliminate unphysi ... [Phys. Fluids 21, 112105 (2009)] published Thu Nov 19, 2009. (Source: Physics of Fluids)

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Multibubble cavitation inception

Physics of Fluids — Fri, 20 Nov 2009 16:11:33 +0100

Masato Ida The inception of cavitation in multibubble cases is studied numerically and theoretically to show that it is different from that in single-bubble cases in several aspects. Using a multibubble model based on the RayleighPlesset equation with an acoustic interaction term, we confirmed that the recentl ... [Phys. Fluids 21, 113302 (2009)] published Thu Nov 19, 2009. (Source: Physics of Fluids)

Markov property of Gaussian states of canonical commutation relation algebras

Journal of Mathematical Physics — Fri, 20 Nov 2009 16:11:32 +0100

Denes Petz and Jozsef Pitrik The Markov property of Gaussian states of canonical commutation relation algebras is studied. The detailed description is given by the representing block matrix. The proof is short and allows infinite dimension. The relation to classical Gaussian Markov triplets is also described. The minimizer of r ... [J. Math. Phys. 50, 113517 (2009)] published Thu Nov 19, 2009. (Source: Journal of Mathematical Physics)

Reactions of simple aromatic heterocycles with niobium cluster ions (n

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Britta Pfeffer, Stephanie Jaberg, and Gereon Niedner-Schatteburg Prior work on benzene activation by size selected niobium cluster cations and anions of up to 30 atoms is extended systematically through studying aromatic poly- and heterocyclic molecules such as naphthalene, pyridine, thiophene, pyrrole, furan, and benzofuran. Naphthalene is found to act much like ... [J. Chem. Phys. 131, 194305 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

Kinetics and morphology of cluster growth in a model of short-range attractive colloids

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

We present results from detailed three-dimensional Brownian dynamics simulations of the self-assembly process in quenched short-range attractive colloids. Clusters obtained in the simulations range from dense faceted crystals to fractal aggregates which show ramified morphology on large length scale ... [J. Chem. Phys. 131, 194908 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

Stochastic bimodalities in deterministically monostable reversible chemical networks due to network topology reduction

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Maxim N. Artyomov, Manikandan Mathur, Michael S. Samoilov, and Arup K. Chakraborty Recently, stochastic simulations of networks of chemical reactions have shown distributions of steady states that are inconsistent with the steady state solutions of the corresponding deterministic ordinary differential equations. One such class of systems is comprised of networks that have irrevers ... [J. Chem. Phys. 131, 195103 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

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Publisher's Note: Transition state analysis of solid-solid transformations in nanocrystals [J. Chem. Phys. 131, 164116 (2009)]

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Michael Grunwald and Christoph Dellago Abstract not available. [J. Chem. Phys. 131, 199901 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

Localized soft modes and the supercooled liquid's irreversible passage through its configuration space

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Asaph Widmer-Cooper, Heidi Perry, Peter Harrowell, and David R. Reichman Using computer simulations, we show that the localized low frequency normal modes of a configuration in a supercooled liquid are strongly correlated with the irreversible structural reorganization of the particles within that configuration. Establishing this correlation constitutes the identificatio ... [J. Chem. Phys. 131, 194508 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

Ab initio molecular dynamics simulation of photoisomerization in azobenzene in the npi state

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Yusuke Ootani, Kiminori Satoh, Akira Nakayama, Takeshi Noro, and Tetsuya Taketsugu Photoisomerization mechanism of azobenzene in the lowest excited state S(npi) is investigated by ab initio molecular dynamics (AIMD) simulation with the RATTLE algorithm, based on the state-averaged complete active space self-consistent field method. AIMD simulations show that cis to trans isomeriza ... [J. Chem. Phys. 131, 194306 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

Swelling and collapse of polyelectrolyte gels in equilibrium with monovalent and divalent electrolyte solutions

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

De-Wei Yin, Monica Olvera de la Cruz, and Juan J. de Pablo The swelling of polyelectrolyte (PE) gels by 1:1 and 2:1 salts is studied via osmotic ensemble Monte Carlo simulations at constant osmotic pressure and electrolyte chemical potential of a reservoir phase in equilibrium with a model PE network. Large molecular weight gels exhibit a remarkable swellin ... [J. Chem. Phys. 131, 194907 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

Publisher's Note: On the kinetics of the Al+Cl reaction: Cluster degradation in consecutive steps [J. Chem. Phys. 131, 174304 (2009)]

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Matthias Olzmann, Ralf Burgert, and Hansgeorg Schnockel Abstract not available. [J. Chem. Phys. 131, 199902 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

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Spin-locking of half-integer quadrupolar nuclei in nuclear magnetic resonance of solids: Second-order quadrupolar and resonance offset effects

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Sharon E. Ashbrook and Stephen Wimperis Spin-locking of spin I=3/2 and I=5/2 nuclei in the presence of small resonance offset and second-order quadrupolar interactions has been investigated using both exact and approximate theoretical and experimental nuclear magnetic resonance (NMR) approaches. In the presence of second-order quadrupolar ... [J. Chem. Phys. 131, 194509 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

A molecular dynamics study of the influence of ionic charge distribution on the dynamics of a molten salt

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

We present the results of molecular dynamics simulations on a model molten salt system and show that changes in the dis ... [J. Chem. Phys. 131, 194507 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

All-atom ab initio native structure prediction of a mixed fold (1FME): A comparison of structural and folding characteristics of various betabetaalpha miniproteins

Journal of Chemical Physics — Fri, 20 Nov 2009 16:11:30 +0100

Eunae Kim, Soonmin Jang, and Youngshang Pak We performed an all-atom ab initio native structure prediction of 1FME, which is one of the computationally challenging mixed fold betabetaalpha miniproteins, by combining a novel conformational search algorithm (multiplexed Q-replica exchange molecular dynamics scheme) with a well-balanced all-atom ... [J. Chem. Phys. 131, 195102 (2009)] published Thu Nov 19, 2009. (Source: Journal of Chemical Physics)

Effect of azimuthally asymmetric reactor components on a parallel plate capacitively coupled plasma

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Jason A. Kenney, Shahid Rauf, and Ken Collins A three-dimensional fluid plasma model is used to investigate the impact of azimuthally asymmetric reactor components on spatial characteristics of parallel plate capacitively coupled plasmas. We consider three scenarios: high frequency (13.56 MHz) argon discharges with, separately, an off-axis circ ... [J. Appl. Phys. 106, 103302 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

The structural parameter optimization of interdigital transducer in single electron transport devices

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Li Song, Hui Yuan, Chuanyu Zhang, Ling Li, Chuan Lu et al. We investigate the influence of the interdigital transducer (IDT) structure on the amplitude of the surface acoustic wave (SAW) in a SAW device. The SAW amplitude at the entrance of the quantum point contact (QPC) is obtained by using coupling-of-modes theory and p-matrix method. The calculated resu ... [J. Appl. Phys. 106, 104508 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

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Size effect on magnetic and ferroelectric properties in BiFeO multiferroic ceramics

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Z. M. Tian, S. L. Yuan, X. L. Wang, X. F. Zheng, S. Y. Yin et al. Magnetic and ferroelectric properties are investigated for the polycrystalline BiFeO ceramics with different grain sizes (602000 nm) synthesized by a modified Pechini method. It shows that magnetic and ferroelectric properties are strongly dependent on the grain size. For the 60 nm samples, the magn ... [J. Appl. Phys. 106, 103912 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Significant suppression of space charge injection into linear low density polyethylene by surface oxyfluorination

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Zhenlian An, Chen Xie, Yue Jiang, Feihu Zheng, and Yewen Zhang Surface oxyfluorination of linear low density polyethylene (LLDPE) was performed to suppress space charge injection and accumulation under direct current high voltage. Significant suppression effect that there is almost no space charge inside LLDPE was obtained, as observed by space charge measureme ... [J. Appl. Phys. 106, 104112 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Computational study of thermocompression bonding of carbon nanotubes to metallic substrates

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Xiaohui Song, Zhiyin Gan, Sheng Liu, Han Yan, and Qiang Lv Thermocompression bonding of carbon nanotubes (CNTs) to metallic substrates is studied using molecular dynamics. The interaction of the CNT and the metal cluster at high temperature is investigated first. For the diffusion bonding process, the effects of temperature and external pressure are examine ... [J. Appl. Phys. 106, 104308 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

The Debye-like relaxation mechanism in poly(vinylidene fluoride-trifluoroethylene) ferroelectric polymers

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

P. F. Liu, P. Gemeiner, X. J. Meng, J. H. Chu, S. Geiger et al. In this work we studied 65-nm-thick poly(vinylidene fluoride-trifluoroethylene) ferroelectric polymers films grown by LangmuirBlodgett onto silicon substrates. Three dielectric anomalies have been unambiguously evidenced. The high temperature one near 380 K corresponds to the ferroelectric-paraelect ... [J. Appl. Phys. 106, 104113 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

A compact interferometric sensor design using three waveguide coupling

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

K. C. Vernon, D. E. Gomez, and T. J. Davis The use of metal stripes for the guiding of plasmons is a well established technique for the infrared regime and has resulted in the development of a myriad of passive optical components and sensing devices. However, the plasmons suffer from large losses around sharp bends, making the compact design ... [J. Appl. Phys. 106, 104306 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

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Zinc and oxygen vacancies in ZnO nanorods

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

A. Travlos, N. Boukos, C. Chandrinou, Ho-Sang Kwack, and Le Si Dang Nominally undoped ZnO nanorods, which have been grown with intentionally incorporated large concentrations of zinc and oxygen vacancies, are studied with electron microscopy and photoluminescence spectroscopy at low temperature. Detailed photoluminescence studies reveal that the concentration of the ... [J. Appl. Phys. 106, 104307 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Decoupling two-step anodization in anodic aluminum oxide

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Kwang Hong Lee and C. C. Wong It is well known that ordered anodic aluminum oxide (AAO) can be fabricated by a two-step anodization process, but in the current approach, pore size and interpore spacing are coupled because the ordering mechanism is expected to be the same in both steps. Here, we demonstrate that, by using a diffe ... [J. Appl. Phys. 106, 104305 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Excitation dynamics in polymer-coated semiconductor quantum dots with integrated dye molecules: The role of reabsorption

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Tobias Niebling, Feng Zhang, Zulqurnain Ali, Wolfgang J. Parak, and Wolfram Heimbrodt Inorganic CdSe/ZnS core-shell quantum dots have been coated with amphiphilic polymers in order to enable their transfer to aqueous solutions. Additionally, ATTO-dye molecules have been embedded in the polymer shell. In this geometry ATTO dye acts as acceptor of the quantum dot donors' excitation. Th ... [J. Appl. Phys. 106, 104701 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Degradation of Staphylococcus aureus bacteria by neutral oxygen atoms

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

U. Cvelbar, M. Mozetic, N. Hauptman, and M. Klanjsek-Gunde The degradation of Staphylococcus aureus bacteria during treatment with neutral oxygen atoms was monitored by scanning electron microscopy. Experiments were performed in an afterglow chamber made from borosilicate glass. The source of oxygen atoms was remote inductively coupled radiofrequency oxygen ... [J. Appl. Phys. 106, 103303 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Field dependence of the adiabatic temperature change in second order phase transition materials: Application to Gd

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

V. Franco, A. Conde, J. M. Romero-Enrique, Y. I. Spichkin, V. I. Zverev et al. The field dependence of the adiabatic temperature change DeltaT of second order phase transition materials is studied, both theoretically and experimentally. Using scaling laws, it is demonstrated that, at the Curie temperature, the field dependence of DeltaT is characterized by H. Therefore, as the ... [J. Appl. Phys. 106, 103911 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

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Effect of kinetic growth parameters on leakage current and ferroelectric behavior of BiFeO thin films

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Vilas Shelke, V. N. Harshan, Sushma Kotru, and Arunava Gupta Epitaxial BiFeO thin films have been grown on (100)-oriented SrTiO and Nb-doped SrTiO substrates using the pulsed laser deposition technique under identical thermodynamic and variable kinetic conditions. The variation of growth kinetics through laser fluence and pulse repetition rate had minimal eff ... [J. Appl. Phys. 106, 104114 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Adjustable resonance frequency and linewidth by Zr doping in Co thin films

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Changjun Jiang, Desheng Xue, Dangwei Guo, and Xiaolong Fan CoZr (40 nm) thin films with different Zr compositions were grown on silicon substrates by radio frequency magnetron sputtering. The coercivity decreased with an increase in the Zr composition. A uniaxial anisotropy existed in the CoZr films, and the anisotropy field of the films decreased from 55 t ... [J. Appl. Phys. 106, 103910 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Extension of the RosencwaigGershoFernelius photothermal deflection spectroscopy model to account for multiple reflections in epitaxial samples

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

I. C. W. Chan and M. Beaudoin The Fernelius extension to the RosencwaigGersho theory for photothermal deflection spectroscopy (PDS) is modified to take into account multiple reflections and light trapping within a thin film-on-substrate system where both the thin film and the substrate can be absorbing. The extended model is use ... [J. Appl. Phys. 106, 103510 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Orientation dependence of ferroelectric behavior of BiFeO thin films

Journal of Applied Physics — Fri, 20 Nov 2009 16:11:29 +0100

Jiagang Wu and John Wang Multiferroic BiFeO (BFO) thin films with (111), (100), (110) preferred, and random orientations were deposited by radio frequency magnetron sputtering on SrRuO-buffered SrTiO(111), SrTiO(100), SrTiO(110), and Pt(111)/Ti/SiO/Si(100) substrates, respectively. The orientation dependences of ferroelectr ... [J. Appl. Phys. 106, 104111 (2009)] published Thu Nov 19, 2009. (Source: Journal of Applied Physics)

Unpinning of a spiral wave anchored around a circular obstacle by an external wave train: Common aspects of a chemical reaction and cardiomyocyte tissue

Chaos — Fri, 20 Nov 2009 16:11:28 +0100

Masanobu Tanaka, Akihiro Isomura, Marcel Horning, Hiroyuki Kitahata, Konstantin Agladze et al. It is well known that spiral waves are often stabilized by anchoring to a local heterogeneity (pinning) and that such pinned waves are rather difficult to eliminate. In the present report, we show that pinned spiral waves can be eliminated through collision with a wave train arriving from the outer ... [Chaos 19, 043114 (2009)] published Thu Nov 19, 2009. (Source: Chaos)

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Superparamagnetic limit to spin-polarized vacuum tunneling from Fe-coated W(001) tips

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

Y. R. Niu and M. S. Altman Superparamagnetic fluctuations of magnetization in thin Fe films that coat a sharp W(001) tip are evident in the spin polarization of field emitted electrons. Fluctuations of polarization between four transverse directions that align with the tip directions are consistent with the in-plane biaxial ... [Appl. Phys. Lett. 95, 203113 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Telescopic hot double wall carbon nanotube for nanolithography

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

A. Popescu and L. M. Woods A custom double wall carbon nanotube for thermal surface modification is proposed. By studying the heat transfer characteristics in the system, it is demonstrated that such a device is capable of producing high resolution patterns on a sample surface. A constant distance between the double wall carb ... [Appl. Phys. Lett. 95, 203507 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Photoluminescence enhancement of Er-doped silica containing Ge nanoclusters

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

J. Guzman, S. J. Shin, C. Y. Liao, C. W. Yuan, P. R. Stone et al. The photoluminescence (PL) of Er-doped silica films containing Ge nanoclusters synthesized by ion implantation was investigated. The area of the 1540 nm Er PL peak was enhanced by up to a factor of 200 by the addition of Ge nanoclusters. The PL enhancement was found to be proportional to the concent ... [Appl. Phys. Lett. 95, 201904 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Hard x-ray phase contrast imaging of black lipid membranes

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

We report hard x-ray phase contrast imaging of black lipid membranes, freely suspended over a micromachined aperture in an aqueous solution. Biomolecular and organic substances can thus be probed in hydrated environments by parallel beam propagation imaging, using coherent multi-kilo-electronvolt x- ... [Appl. Phys. Lett. 95, 203703 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Superhydrophobic floatability of a hydrophilic object driven by edge effect

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

Feng-Ming Chang, Yu-Jane Sheng, and Heng-Kwong Tsao It is generally believed that a water-repellent surface is necessary for small insects to stand on water. Through a combined experimental and theoretical study, we demonstrate that an object with hydrophilic surface can float with apparent contact angle greater than 90 degrees due to edge effect. T ... [Appl. Phys. Lett. 95, 204107 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

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Electrohydrodynamic repulsion of droplets falling on an insulating substrate in an electric field

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

Bumjoo Kim, Intae Kim, Sang W. Joo, and Geunbae Lim Control technique for charged droplets, named as electrohydrodynamic droplet repulsion (EDR), is reported. Charged droplets emitting from a capillary and falling down toward an insulating substrate are deflected from their intended impact point due to the like polarity of previously fallen droplets. ... [Appl. Phys. Lett. 95, 204106 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Reflection-mode sensing using optical microresonators

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

Barry Koch, Yasha Yi, Jun-Ying Zhang, Stephen Znameroski, and Terry Smith The authors present an approach for applying optical microring resonators to sensing. The approach relies on the interaction of the resonator with a nanoparticle taggant, which can induce coupling between forward and backward propagating traveling-wave resonant modes of the device. In the convention ... [Appl. Phys. Lett. 95, 201111 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Four discrete Hall resistance states in single-layer Fe film for quaternary memory devices

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

We report the realization of four distinct magnetic states using single layers of Fe at room temperature. When the Fe film was grown on the vicinal surface of GaAs, the fourfold-symmetric magnetization along crystallographic direction give rise to four distinct Hall resistance values due to the diff ... [Appl. Phys. Lett. 95, 202505 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Autonomous microfluidic transport using electrowetting-based valves and integrated cells

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

Papaorn Siribunbandal, Shigeki Yamaguchi, Kenichi Kojima, Junji Fukuda, and Hiroaki Suzuki Autonomous control of the transport of solutions in microfabricated flow channels using electrowetting-based valves and integrated electrochemical cells is proposed. An electrowetting-based valve formed with a gold electrode was opened when an electrolyte solution reached a zinc electrode in a contr ... [Appl. Phys. Lett. 95, 204105 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Electronic structure of substitutional Mn in epitaxial InMnSb film

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

N. D. Parashar, D. J. Keavney, and B. W. Wessels The magnetic and electronic structure of Mn in InMnSb ferromagnetic semiconductor thin film was studied by x-ray absorption spectroscopy and x-ray magnetic circular dichroism. Comparison with atomic multiplet calculations suggests that manganese substitutes on sites with tetrahedral symmetry. Strong ... [Appl. Phys. Lett. 95, 201905 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

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Dynamical and quasistatic structural relaxation paths in PdNiP glass

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

A. Kahl, T. Koeppe, D. Bedorf, R. Richert, M. L. Lind et al. By sequential heat treatment of a PdNiP metallic glass at temperatures and durations for which alpha-relaxation is not possible, dynamic, and quasistatic relaxation paths below the glass transition are identified via ex situ ultrasonic measurements following each heat treatment. The dynamic relaxati ... [Appl. Phys. Lett. 95, 201903 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Fully bendable polymer light emitting devices with carbon nanotubes as cathode and anode

Applied Physics Letters — Fri, 20 Nov 2009 16:11:18 +0100

Zhibin Yu, Liangbing Hu, Zhitian Liu, Mingliang Sun, Meiliang Wang et al. Polymer light emitting devices were fabricated by roll lamination using single-walled carbon nanotubes as both anode and cathode. The devices exhibited a low turn-on voltage of 3.8 V, high brightness of 1400 cd/m at 10 V and maximum efficiency of 2.2 cd/A at 480 cd/m. The devices are also highly t ... [Appl. Phys. Lett. 95, 203304 (2009)] published Thu Nov 19, 2009. (Source: Applied Physics Letters)

Precise balancing of viscous and radiation forces on a particle in liquid-filled photonic bandgap fiber

Optics Letters — Fri, 20 Nov 2009 16:11:01 +0100

A great challenge in microfluidics is the precise control of laser radiation forces acting on single particles or cells, while allowing monitoring of their optical and chemical properties. We show that, in the liquid-filled hollow core of a single-mode photonic crystal fiber, a micrometer-sized ... (Source: Optics Letters)

Sandwiched long-period fiber grating filter based on periodic SU8-thick photoresist technique

Optics Letters — Fri, 20 Nov 2009 16:11:01 +0100

A loss-tunable sandwiched long-period fiber grating (SLPFG) filter is proposed in this Letter. This SLPFG utilized thick SU8 photoresist layers to induce refractive index modulations, and ultrahigh period precision was hence achieved. The external force required to tune this SLPFG filter is about ... (Source: Optics Letters)

Extreme ultraviolet multilayer mirror with near-zero IR reflectance

Optics Letters — Fri, 20 Nov 2009 16:11:01 +0100

We have developed a multilayer mirror for extreme ultraviolet (EUV) radiation that has low reflectance for IR radiation at 10.6 μm wavelength. The mirror is based on a multilayer coating comprising alternating layers of diamondlike carbon and silicon, for which we demonstrate an EUV ... (Source: Optics Letters)

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Design of a micro-opto-electro-mechanical-system-based near-infrared hyperspectral imager

Applied Optics — Fri, 20 Nov 2009 16:11:00 +0100

We present the development of an imaging spectrometer for the near infrared (NIR) using a micro-opto-electromechanical system. A diffraction grating has been etched into the surface of a micromechanical scanning mirror made of silicon and is used to scan the object space and to disperse the NIR ... (Source: Applied Optics)

Experimental study on the 1550 nm all fiber heterodyne laser range finder

Applied Optics — Fri, 20 Nov 2009 16:11:00 +0100

In this paper, a 1550 nm all fiber monostatic laser range finder system based on linear chirp modulation and heterodyne detection is presented. The fiber end face signal is used as a range starting indicator. The transmitted laser power is 5 mW with a laser pulse length of 131 μs and a linear ... (Source: Applied Optics)

Binary systems share stardust

PhysicsWeb News — Fri, 20 Nov 2009 15:58:51 +0100

Rare glimpse of planet formation in binary star system (Source: PhysicsWeb News)

NEW LEJ Light Source for fluorescence excitation in Microscopy

PhysicsWeb Products & Press — Fri, 20 Nov 2009 15:58:28 +0100

This compact device is the ideal external light source for fluorescence excitation in microscopy. (Source: PhysicsWeb Products & Press)

Dose consumption for quality assurance and maintenance at a dedicated IORT accelerator.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Hensley FW Dedicated accelerators for intraoperative radiation therapy (IORT) are operated at high dose rates in order to achieve short treatment times within which the anaesthetisized patient must be remotely monitored, e.g. via video cameras and telemetric anesthesia instruments. Due to these high dose rates, large doses accumulate from the irradiations necessary for quality assurance (QA) and maintenance. In practice, the dose load for QA, maintenance and repairs will probably by far exceed the patient dose. The total dose consumption for all of these actions must be considered in facility licensing, in radiation protection assessments and in the shielding calculations. Dose consumption for QA and maintenance was assessed for the dedicated IORT facility at Author's Universi...

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Analysis of couch position tolerance limits to detect mistakes in patient setup.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Hadley SW, Lam KL, Balter JM This work investigates the use of the tolerance limits on the treatment couch position to detect mistakes in patient positioning and warn users of possible treatment errors. Computer controlled radiotherapy systems use the position of the treatment couch as a surrogate for patient position and a tolerance limit is applied against a planned position. When the couch is out of tolerance a warning is sent to a user to indicate a possible mistake in setup. A tight tolerance may catch all positioning mistakes while as the same time sending too many warnings; while a loose tolerance will not catch all mistakes. We develop a statistical model of the absolute position for the three translational axes of the couch. The couch position for any fraction is cons...

Rapid fabrication of custom patient biopsy guides.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Rajon DA, Bova FJ, Friedman WA Image guided surgery is currently performed using frame-based as well as frameless approaches. In order to reduce the invasive nature of stereotactic guidance as well as to reduce the cost in both equipment and time required within the operating room we investigated the use of rapid prototyping (RP) technology. In our approach we fabricated custom patient specific face-masks and guides that can be applied to the patient during surgery. These guides provide a stereotactic reference for the accurate placement of surgical tools to a pre-planned target along a pre-planned trajectory. While the use of RP machines has previously been shown to be satisfactory for the accuracy standpoint, one of our design criteria, completing the entire built and introd...

Detection of electron beam energy variations using a computed radiography system.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Cai YC, Ge Y, Bernard DA, Turian JV, Chu JC A method to evaluate the electron beam energy constancy by employing the computed radiography (CR) system has been developed. In this method, a right triangular plastic wedge is used to produce a curve of the CR storage phosphor plate signal versus the wedge thickness. The curve which resembles the percentage depth ionization curve of the clinical electron beams can be used to derive the energy constancy metric EC50. The sensitivity of the method was tested using polystyrene sheets of variable thicknesses. For electron energies up to 12 MeV energy changes induced by 1.5 mm thick polystyrene can be detected, while a 2.3 mm thick polystyrene sheet is required for higher energies. The measurements were carried out over a two years perio...

4D-PET data sorting into different number of phases: a NEMA IQ phantom study.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

This study aims at evaluating the dependence of 4D-PET data sorting on the number of phases in which the respiratory cycle can be divided. The issue is to find the best compromise to reduce the conflicting effects induced by increasing the number of phases: lesion motion on each set of images decreases, but on the other hand image noise increases. The IQ NEMA 2001 IEC body phantom was used to simulate the movement of neoplastic lesions in the thorax and abdomen, investigating the effect of target size (10-37 mm), lesion to background activity concentrations ratio (4-to-1 and 8-to-1), total acquisition time (3, 6, 12, 20 min) and number of phase partition (1, 2, 4, 6, 8, 10, 13). The phantom was moved in a cranial-caudal direction with an excursion of 25 mm and with a period of 4.0 s. Five ...

Characterization of cylindrical ionization chambers for patient specific IMRT QA.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Fraser DJ, Parker W, Seuntjens J Proven conventional dosimetry techniques do not provide accuracy and precision in the measurement of inverse planned intensity modulated radiation therapy (IMRT) fields. Dynamic and step-and-shoot multileaf collimation (DMLC/SMLC) challenge current ionization chamber dosimetry practices. Ionization chamber performance in these fields is evaluated for three cylindrical chambers of varying volumes (PinPoint (PP): 0.015 cm3, IC10: 0.13 cm3, Farmer type NE2571 (FT): 0.69 cm3) in terms of measurement reproducibility, dose measurement linearity, and IMRT dose measurements. Fifty IMRT patient specific quality assurance dose measurements were performed with each chamber. DMLC measurements are compared between chambers, and to dose calculations from a c...

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A positioning QA procedure for 2D/2D (kV/MV) and 3D/3D (CT/CBCT) image matching for radiotherapy patient setup.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Guan HH, Hammoud R, Yin F A daily QA procedure for Varian's on-board imager (OBI) and portal vision (PV) device was developed. The procedure was to check: (1) the two imaging device's isocenters (digital graticules) coincides with linac's isocenter (to a pre-specified accuracy) and (2) the positional difference detected by 2D/2D image matching can be reliably transferred to couch motion. A cube isocenter phantom was used and two sets of 1 mm metal balls (bb) were placed on the phantom to define two separate spatial points (locations.) The first set defined the isocenter at the phantom center and the second set defined a point 1.5cm anterior, 1.5cm inferior, and 1.5cm right lateral from the isocenter. An axial scan of the phantom was acquired (2mm slice thickness and 1mm spacin...

Suitability of radiochromic films for dosimetry of very-low energy X-rays.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

This study examined the response characteristics of three commercially available radiochromic films when exposed to very low energy (50 kVp) X-rays. The aim was to evaluate the films for potential use in 2D dosimetry for a low-kV intraoperative radiotherapy (IORT) device. Dose-response relationships were obtained for Gafchromic(R) EBT, XR-RV2 and XR-QA film in water at several distances from the IORT source in order to evaluate the effect of changes in X-ray spectrum on response. It was found that the dose-rates from the source were excessive for use of the XR-QA film, and that all three film types films showed significant energy dependence within the limits of measurement uncertainty. This is in contrast to previous studies indicating less or negligible energy response. All films showed n...

A diagnostic tool for basic daily quality assurance of a Tomotherapy Hi*Art machine.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Conclusion: This tool makes it possible to perform an easy-to-use and fast basic daily quality assurance check featuring an output as well as an energy evaluation. Ideally this tool should offer also the combined dosimetry check of jaw width, couch speed, leaf latency, output, leaf/gantry synchrony and lasers. This will be investigated in the future. PMID: 19918225 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)

Clinical implementation of electron energy changes of varian linear accelerators.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

In this study we investigated electron beam characteristics and implemented two new electron beams on two Varian linear accelerators. Comprehensive tests and measurements indicated the new electron beams met all dosimetry parameter criteria and operational safety standards. With these two new electron beams in addition to existing electron beams we were able to provide a choice of electron beams which had d90depth between 1.5 cm and 6.0 cm and from 1.5 cm to 4.0 cm in 0.5 cm increment to meet our clinical need. PMID: 19918226 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)

From phase-based to displacement-based gating: A software tool to facilitate respiration-gated radiation treatment.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Conclusions: Real-time phase gating can lead to inaccuracies when the breathing trace is irregular or because of other unidentified reasons. In such cases, the in-gate displacement differed by as much as 2 mm between phase-based and displacement-based gating for the real-time phase calculation. Displacement-based gating is equivalent to phase-based gating for retrospectively-calculated phase information. PMID: 19918227 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)

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Treatment planning of Epithelial Ovarian Cancers using Helical Tomotherapy.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

The objective parameters were to obtain uniform and adequate target coverage with maximum OAR sparing. HT plans were generated for five patients with field-width of 5.0/2.5cm, modulation factor of 3.5/3.0, and a pitch of 0.3. A dose of 25Gy in 25 fractions was prescribed to the abdomen with a simultaneous boost of 45Gy in 25 fractions to the pelvis. Dose-volume parameters and various indices were analyzed and compared. Mean volume (standard-deviation) of abdominal and pelvic PTV (planning target volume) was 6630 (+/-450) cm3 and 1235 (+/-98)cm3 respectively. Mean length of PTV in cranio-caudal direction was 41(+/-4) cm. Volume receiving 95% and 107% of the prescription dose, V95% and V107% was 95.6(+/-2.7) % and 2.6(+/-0.5) % for abdominal-PTV, and 95.7(+/-2.4) % and 0% for pelvic-PTV resp...

Analysis of the evolution of acceptance indices of quality control parameters for x-ray equipment in the state of são paulo.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Analysis of the evolution of acceptance indices of quality control parameters for x-ray equipment in the state of são paulo. J Appl Clin Med Phys. 2009;10(4):3007 Authors: Ebisawa ML, Magon Mde F, Mascarenhas YM The quality assurance (QA) of radiographic images based on the operating conditions of X-ray equipment is essential for good image quality, accurate medical diagnostics and to prevent the exposure of health professionals and patients to unnecessary doses of ionizing radiation. This paper presents a historical analysis of 1,635 Quality Assurance Technical Reports by Health Institutions in the state of São Paulo, Brazil, over a 7-year period. Based on acceptable limits for variations between nominal and measured parameters as the variable to determine the qualit...

Optimization of photon beam energy in aperture-based inverse planning.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: St-Hilaire J, Sévigny C, Beaulieu F, Gingras L, Tremblay D, Beaulieu L Optimal choice of beam energy in radiation therapy is easy in many well-documented cases, but less obvious in some others. Low-energy beams may provide better conformity around the target than their high-energy counterparts due to reduced lateral scatter, but they also contribute to overdosage of peripheral normal tissue. Beam energy was added as an optimization parameter in an automatic aperture-based inverse planning system. We have investigated two sites (prostate and lung), representative of deep-seated and moderately deep-seated tumors. For each case and different numbers of beam incidences, four plans were optimized: 6 MV, 23 MV, and mixed energy plans with one or two energies per incidence. Each...

The effect of interfraction prostate motion on IMRT plans: a dose-volume histogram analysis using a Gaussian error function model.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Chow JC, Jiang R, Markel D The Gaussian error function model, containing pairs of error and complementary error functions, was used to carry out cumulative dose-volume histogram (cDVH) analysis on prostate intensity modulated radiation therapy (IMRT) plans with interfraction prostate motion. Cumulative DVHs for clinical target volumes (CTVs) shifted in the anterior-posterior directions based on a 7-beam IMRT plan were calculated and modeled using the Pinnacle3 treatment planning system and a Gaussian error function, respectively. As the parameters in the error function model, namely, a, b and c were related to the shape of the cDVH curve, evaluation of cDVHs corresponding to the prostate motion based on the model parameters becomes possible as demonstrated in this study. It wa...

Accuracy of automatic couch corrections with on-line volumetric imaging.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Conclusions: Remote automatic couch movement is reliable and effective for adjusting the patient position with precision of ~1 mm. Residual error observed in this study demonstrates that displacement is minimal after remote couch adjustment for all patients. PMID: 19918232 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)

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Effect of Collimator and Couch Angle Change on Breast IMRT Dose Distributions.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

The objective of this work is to investigate the effects of the collimator and the couch angle change on the dose distribution for breast cancer treatment using intensity modulated tangential photon beams, and thus to determine the clinical acceptable range of the angle change for routine treatment. Ten breast cases treated with intensity modulated tangential photon beams were analyzed in this study. Patient-specific CT data and the RTP files obtained from our home-grown Monte Carlo based breast IMRT treatment planning system were used for IMRT dose re-calculation with collimator or couch angle changes. The isodose distributions and DVHs were compared with the original plans and the effects of the collimator and couch angle change to breast IMRT dose distributions were evaluated. Our resul...

Algorithm for correcting optimization convergence errors in Eclipse.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Zacarias AS, Mills MD IMRT plans generated in Eclipse use a Dose Volume Optimizer (DVO) algorithm to evaluate dose for optimization and a more accurate algorithm for a final Volume Dose (VD) calculation, the Analytical Anisotropic Algorithm (AAA). The use of the DVO introduces Optimization Convergence Errors (OCE's) into an IMRT plan. Eclipse has a feature where optimization may be performed on top of an existing base plan. When the base plan is an optimized IMRT plan, a second optimization can compensate for errors in the base plan. Errors in the base plan are demonstrated to originate in the DVO. An IMRT plan containing the same field arrangement as the initial base plan may be generated by adding the initial plan optimal fluence to the dose correcting plan optimal fluence. ...

Direct machine parameter optimization for intensity modulated radiation therapy (IMRT) of oropharyngeal cancer - a planning study.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Dobler B, Koelbl O, Bogner L, Pohl F The purpose of the study was to investigate the potential of direct machine parameter optimization (DMPO) to achieve parotid sparing without compromising target coverage in IMRT of oropharyngeal cancer as compared to fluence modulation with subsequent leaf sequencing (IM) and forward planned 2-step arc therapy (IMAT). IMRT plans were generated for 10 oropharyngeal cancer patients using DMPO and IM. The resulting dose volume histograms (DVH) were evaluated with regard to compliance with the dose volume objectives (DVO) and plan quality. DMPO met the DVO for the targets better than IM but violated the DVO to the parotids in some cases. DMPO provided better target coverage and dose homogeneity than IM and comparable to IMAT. Dose to the paroti...

Comparing planning time, delivery time and plan quality for IMRT, RapidArc and Tomotherapy.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Oliver M, Ansbacher W, Beckham WA The purpose of this study is to examine plan quality, treatment planning time, estimated treatment delivery time and other dose metrics for 5 and 9 field sliding window IMRT (IMRT5 and IMRT9), single and dual arc Rapid Arc (RA1 and RA2) and Tomotherapy (TOMO). Four cylindrical virtual phantoms were created each with its own distinct set of contours. The contour sets were 2D contours on the axial slice extended in the superior-inferior direction. The prescription dose in all cases was 2 Gy per fraction. IMRT plans were created with 5 or 9 equally spaced beams and RA plans were created with either 1 or 2 complete rotations of the gantry. TOMO plans were created with typical planning parameters. Plans were evaluated based on the ability to meet d...

Prostate positioning errors associated with two automatic registration based image guidance strategies.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

The objective of this work is to quantify prostate misplacement that results from automatic bone matching (BM) and image matching (IM) registration algorithms. 204 MVCT images from 8 high risk tomotherapy prostate patients were incorporated into this retrospective study. BM and IM registration algorithms based on maximization of mutual information of bony anatomy only and the entire image, respectively, were used to independently register MVCT images to their respective planning images. A correlation coefficient based algorithm that uses known planning CT contour information was used for automatic prostate localization in each MVCT image. Daily prostate misplacement was determined by repositioning as calculated from the BM and the IM algorithms. Mean (+/- SD) and maximum 3D prostate positi...

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Evaluation of a biplanar diode array dosimeter for quality assurance of step-and-shoot IMRT.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

We described and characterized a novel biplanar diode array, and demonstrated its applicability to dosimetric QA of the step-and-shoot IMRT. It is the first commercially available device of its kind specifically designed for measurements at varying gantry angles. The detector consists of a cylindrical PMMA phantom with two orthogonal detector boards. There are a total of 1069 p-type 1 mm wide diode detectors covering the measurement area of 20 x 20 cm2 in each of the measurement planes. The orthogonal detector arrays ensure that the dose modulation information is not lost regardless of the beam incidence angle. For absolute calibration, the dose to the reference detector is calculated at the appropriate SSD and radiological depth by the treatment planning system and is scaled by the measur...

Information technology resource management in radiation oncology.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Siochi RA, Balter P, Bloch C, Bushe H, Mayo C, Curran B, Feng W, Kagadis G, Kirby T, Stern R The ever-increasing data demands in a radiation oncology (RO) clinic require medical physicists to have a clearer understanding of the information technology (IT) resource management issues. Clear lines of collaboration and communication among administrators, medical physicists, IT staff, equipment service engineers and vendors need to be established. In order to develop a better understanding of the clinical needs and responsibilities of these various groups, an overview of the role of IT in RO is provided. This is followed by a list of IT related tasks and a resource map. The skill set and knowledge required to implement these tasks are described for the various RO professionals. Fin...

Editorial: 10 years of the JACMP.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Starkschall G PMID: 19918240 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)

Guest editorial: tenth anniversary of the journal of applied clinical medical physics.

Journal of Applied Clinical Medical Physics — Fri, 20 Nov 2009 06:02:03 +0100

Authors: Almond P PMID: 19918241 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)

The equivalence of multi-criteria methods for radiotherapy plan optimization.

Physics in Medicine and Biology — Fri, 20 Nov 2009 05:56:18 +0100

Authors: Breedveld S, Storchi PR, Heijmen BJ Several methods can be used to achieve multi-criteria optimization of radiation therapy treatment planning, which strive for Pareto-optimality. The property of the solution being Pareto optimal is desired, because it guarantees that no criteria can be improved without deteriorating another criteria. The most widely used methods are the weighted-sum method, in which the different treatment objectives are weighted, and constrained optimization methods, in which treatment goals are set and the algorithm has to find the best plan fulfilling these goals. The constrained method used in this paper, the 2pc (2-phase -constraint) method is based on the -constraint method, which generates Pareto-optimal solutions. Both approaches are uniquely related ...

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The correlation between mass-averaged SAR and temperature elevation in the human head model exposed to RF near-fields from 1 to 6 GHz.

Physics in Medicine and Biology — Fri, 20 Nov 2009 05:56:15 +0100

Authors: Hirata A, Fujiwara O In the present study, we investigate the relationship between the mass-averaged specific absorption rate (SAR) and temperature elevation in anatomically based Japanese head models due to the dipole antenna. A homogeneous cubical model is also used as a basis for the investigation. The frequency region considered is from 1 to 6 GHz. We focused on the averaging mass of SAR, which maximizes the correlation with local temperature elevation. An averaged SAR over 10 g was found to reasonably correlate with local temperature elevation even for frequencies from 3 to 6 GHz. The dominant factor influencing the correlation between mass-averaged SAR and temperature elevation is suggested to be the thermal diffusion length in biological tissue, together with the penetr...

Combined optical and single photon emission imaging: preliminary results.

Physics in Medicine and Biology — Fri, 20 Nov 2009 05:56:11 +0100

Authors: Boschi F, Spinelli AE, D'Ambrosio D, Calderan L, Marengo M, Sbarbati A In vivo optical imaging instruments are generally devoted to the acquisition of light coming from fluorescence or bioluminescence processes. Recently, an instrument was conceived with radioisotopic detection capabilities (Kodak in Vivo Multispectral System F) based on the conversion of x-rays from the phosphorus screen. The goal of this work is to demonstrate that an optical imager (IVIS 200, Xenogen Corp., Alameda, USA), designed for in vivo acquisitions of small animals in bioluminescent and fluorescent modalities, can even be employed to detect signals due to radioactive tracers. Our system is based on scintillator crystals for the conversion of high-energy rays and a collimator. No hardware modification...

The effect of electron collimator leaf shape on the build-up dose in narrow electron MLC fields.

Physics in Medicine and Biology — Fri, 20 Nov 2009 05:56:08 +0100

Authors: Vatanen T, Traneus E, Väänänen A, Lahtinen T Previously, we have found that the build-up dose from abutting narrow electron beams formed with unfocussed electron multi-leaf collimator (eMLC) steal leaves was higher than with the respective open field. To investigate more closely the effect of leaf material and shape on dose in the build-up region, straight, round (radius 1.5 cm) and leaf ends with a different front face angle of alpha (leaf front face pointing towards the beam axis at an angle of 90 - alpha) made of steel, brass and tungsten were modelled using the BEAMnrc code. Based on a treatment head simulation of a Varian 2100 C/D linac, depth-dose curves and profiles in water were calculated for narrow 6, 12 and 20 MeV eMLC beams (width 1.0 cm, length 10 c...

Comparison of IMRT planning with two-step and one-step optimization: a strategy for improving therapeutic gain and reducing the integral dose.

Physics in Medicine and Biology — Fri, 20 Nov 2009 05:56:05 +0100

Authors: Abate A, Pressello MC, Benassi M, Strigari L The aim of this study was to evaluate the effectiveness and efficiency in inverse IMRT planning of one-step optimization with the step-and-shoot (SS) technique as compared to traditional two-step optimization using the sliding windows (SW) technique. The Pinnacle IMRT TPS allows both one-step and two-step approaches. The same beam setup for five head-and-neck tumor patients and dose-volume constraints were applied for all optimization methods. Two-step plans were produced converting the ideal fluence with or without a smoothing filter into the SW sequence. One-step plans, based on direct machine parameter optimization (DMPO), had the maximum number of segments per beam set at 8, 10, 12, producing a directly deliverable sequence. Mor...

Optimizing the spatial resolution of photonic crystal label-free imaging

Applied Optics — Fri, 20 Nov 2009 05:00:00 +0100

A theory is derived to describe the relationship between photonic crystal (PC) label-free imaging resolution and PC resonance spectral linewidth and location. PCs are fabricated and patterned with a resolution standard photomask in order to verify this relationship experimentally. Two distinct ... (Source: Applied Optics)

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Feasibility study on twisted nematic liquid-crystal cell with two cross-embedded wire-grid polarizers as alignment and electrode for projection displays

Applied Optics — Fri, 20 Nov 2009 05:00:00 +0100

For this study, twisted nematic liquid crystals (TN-LCs) are sandwiched between two cross-embedded wire-grid polarizers (WGPs) as alignment and electrodes for projection displays. In the proposed device, the WGPs replace not only the sheet polarizers in a conventional TN-LC cell, but also the front ... (Source: Applied Optics)

Control of optical mode properties in cross-slot waveguides

Applied Optics — Fri, 20 Nov 2009 05:00:00 +0100

A cross-slot waveguide geometry provides high confinement of the mode field of both fundamental quasi-TE and quasi-TM modes in geometrically perpendicular slots. A unique possibility to tailor optical mode characteristics such as effective index and confinement factor quite independently for the ... (Source: Applied Optics)

Khan documents confirms Chinese help in nuclear weapon research

Physics Today News Picks — Fri, 20 Nov 2009 00:00:00 +0100

washingtonpost.com: In 1982, a Pakistani military C-130 left the western Chinese city of Ürümqi with a highly unusual cargo: enough weapons-grade uranium for two atomic bombs, and a blueprint of how to build one say accounts written by the father of Pakistan's nuclear weapons program, Abdul Qadeer Khan. Khan is currently under house arrest. The uranium transfer was part of a broad-ranging, secret nuclear deal approved years earlier by Chinese premier Mao Zedong and Prime Minister Zulfikar Ali Bhutto. US officials say they have known about the transfer for decades and once privately confronted the Chinese—who denied it—but have never raised the issue in public or sought to impose direct sanctions on China for it. The transfer also started a chain of proliferation in which...

Russia restructures physics labs

Physics Today News Picks — Fri, 20 Nov 2009 00:00:00 +0100

Science: Four of Russia's most prominent physics labs are to be merged into a new national research center. The institutes, which have languished in the post-Soviet era, have cautiously welcomed the raised profile the merger will bring. But a different reform aimed at separating basic and applied research at one of the institutes—the Kurchatov Institute in Moscow, Russia's premier lab for nuclear energy research--has researchers up in arms. The merger, announced in a presidential decree last month, will combine the Institute for High Energy Physics (IHEP) in Protvino, 100 kilometers south of Moscow; the B. P. Konstantinov Petersburg Nuclear Physics Institute (PNPI) in St. Petersburg; and two Moscow labs--the Institute for Theoretical and Experimental Physics (ITEP) and the Kurchat...

A light touch on liquid droplets

Physics Today News Picks — Fri, 20 Nov 2009 00:00:00 +0100

Nature: With microfluidic devices gaining prominence for many applications in chemistry and biology, the hunt is on to find ways of accurately controlling the motion of liquid droplets. In Angewandte Chemie, Antoine Diguet et al. describe a method for using light to trap and move oil droplets floating on an aqueous solution. Related Link Photomanipulation of a droplet by the chromocapillary effect (Source: Physics Today News Picks)

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Design, construction, and calibration of a three-axis, high-frequency magnetic probe (B-dot probe) as a diagnostic for exploding plasmas

Review of Scientific Instruments — Thu, 19 Nov 2009 16:14:41 +0100

E. T. Everson, P. Pribyl, C. G. Constantin, A. Zylstra, D. Schaeffer et al. A three-axis, 2.5 mm overall diameter differential magnetic probe (also known as B-dot probe) is discussed in detail from its design and construction to its calibration and use as diagnostic of fast transient effects in exploding plasmas. A design and construction method is presented as a means to r ... [Rev. Sci. Instrum. 80, 113505 (2009)] published Wed Nov 18, 2009. (Source: Review of Scientific Instruments)

Long-distance correlation and zonal flow structures induced by mean E x B shear flows in the biasing H-mode at TEXTOR

Physics of Plasmas — Thu, 19 Nov 2009 16:14:40 +0100

Y. Xu, S. Jachmich, R. R. Weynants, M. Van Schoor, M. Vergote et al. Long-distance toroidal correlations of potential and density fluctuations have been investigated at the TEXTOR tokamak [H. Soltwisch et al., Plasma Phys. Controlled Fusion 26, 23 (1984)] in edge electrode-biasing experiments. During the biasing-induced H-mode, the dc E x B shear flow triggers a zona ... [Phys. Plasmas 16, 110704 (2009)] published Wed Nov 18, 2009. (Source: Physics of Plasmas)

Current driven instability in collisional dusty plasmas

Physics of Plasmas — Thu, 19 Nov 2009 16:14:40 +0100

B. P. Pandey, S. V. Vladimirov, and A. Samarian The current driven electromagnetic instability in a collisional, magnetized, dusty medium is considered in the present work. It is shown that in the presence of the magnetic field aligned current, the low-frequency waves in the medium can become unstable if the ratio of the current to the ambient fi ... [Phys. Plasmas 16, 113708 (2009)] published Wed Nov 18, 2009. (Source: Physics of Plasmas)

Effects of trapped electrons on electromagnetic fields in an oblique shock wave

Physics of Plasmas — Thu, 19 Nov 2009 16:14:40 +0100

Mieko Toida and Kenta Shikii A magnetosonic shock wave propagating obliquely to an external magnetic field can trap electrons and accelerate them to ultrarelativistic energies. The effect of trapped electrons on electromagnetic fields in a shock wave is studied by theory and particle simulations. The expressions for field stren ... [Phys. Plasmas 16, 112305 (2009)] published Wed Nov 18, 2009. (Source: Physics of Plasmas)

Destabilizing effect of density gradient on the KelvinHelmholtz instability

Physics of Plasmas — Thu, 19 Nov 2009 16:14:40 +0100

L. F. Wang, C. Xue, W. H. Ye, and Y. J. Li In this paper, we derive explicit analytic formulas for the linear growth rate and frequency of the KelvinHelmholtz instability in fluids with the density gradient. The analytic formulas are in excellent agreement with the results of two-dimensional numerical simulation. We found that the density gr ... [Phys. Plasmas 16, 112104 (2009)] published Wed Nov 18, 2009. (Source: Physics of Plasmas)

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Dust charge and ion drag forces in a high-voltage, capacitive radio frequency sheath

Physics of Plasmas — Thu, 19 Nov 2009 16:14:40 +0100

I. Denysenko, K. Ostrikov, and N. A. Azarenkov The charge of an isolated dust grain and ion drag forces on the grain in a collisionless, high-voltage, capacitive rf sheath are studied theoretically. The studies are carried out assuming that the positive ions are monoenergetic, as well as in more realistic approximation, assuming that the time-av ... [Phys. Plasmas 16, 113707 (2009)] published Wed Nov 18, 2009. (Source: Physics of Plasmas)

Dust charging effects on test charge potential in a multi-ion dusty plasma

Physics of Plasmas — Thu, 19 Nov 2009 16:14:40 +0100

S. Ali The DebyeHuckel and oscillatory wake potentials caused by a test charge are studied in a multi-ion dusty plasma, whose constituents are the Boltzmann distributed electrons and light positive ions, the heavy mobile negative ions, and static but charge fluctuating dust particles. For this purpose, flu ... [Phys. Plasmas 16, 113706 (2009)] published Wed Nov 18, 2009. (Source: Physics of Plasmas)

Fitting the dielectric response of collisionless plasmas by continued fractions

Physics of Plasmas — Thu, 19 Nov 2009 16:14:40 +0100

August Wierling An approximation scheme for the dielectric response of thermal collisionless plasmas at arbitrary degeneracy is presented. A T-fraction representation is obtained from the known expansions of the real part of the dielectric function for small and large arguments. The partial numerators and denominat ... [Phys. Plasmas 16, 112105 (2009)] published Wed Nov 18, 2009. (Source: Physics of Plasmas)

Comment on Heat transfer in vacuum packaged microelectromechanical system devices [Phys. Fluids 20, 017103 (2008)]

Physics of Fluids — Thu, 19 Nov 2009 16:14:39 +0100

Yoshio Sone It is pointed out that the solution of a free molecular gas in a bounded domain proposed as speculation in Sec. II of Cai [Phys. Fluids 20, 017103 (2008)] and in Sec. II of Cai and Liu [Phys. Fluids 20, 067105 (2008)] and its result of the vanishing of flow velocity were rigorously derived under a m ... [Phys. Fluids 21, 119101 (2009)] published Wed Nov 18, 2009. (Source: Physics of Fluids)

Continuous spectrum analysis of roughness-induced transient growth

Physics of Fluids — Thu, 19 Nov 2009 16:14:39 +0100

N. A. Denissen and E. B. White Continuous spectrum amplitude distributions are calculated for transiently growing roughness-induced perturbations in a flat-plate boundary layer. A direct method is employed when the complete flow is known via direct numerical simulation. A new method using regularizing functionals is developed for ... [Phys. Fluids 21, 114105 (2009)] published Wed Nov 18, 2009. (Source: Physics of Fluids)

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Inertial range scaling of the scalar flux spectrum in two-dimensional turbulence

Physics of Fluids — Thu, 19 Nov 2009 16:14:39 +0100

W. J. T. Bos, B. Kadoch, K. Schneider, and J.-P. Bertoglio Two-dimensional statistically stationary isotropic turbulence with an imposed uniform scalar gradient is investigated. Dimensional arguments are presented to predict the inertial range scaling of the turbulent scalar flux spectrum in both the inverse cascade range and the enstrophy cascade range for ... [Phys. Fluids 21, 115105 (2009)] published Wed Nov 18, 2009. (Source: Physics of Fluids)

Clebsch parameterization: Basic properties and remarks on its applications

Journal of Mathematical Physics — Thu, 19 Nov 2009 16:14:38 +0100

Z. Yoshida The Clebsch parameterization (u=[del][cursive phi]+alpha[del]beta) has advantages in elucidating structural properties of vector fields; for example, it helps formulating the Hamiltonian form of ideal fluid mechanics, representing topological constraints (Casimir invariants), integrating the Cauchy ... [J. Math. Phys. 50, 113101 (2009)] published Wed Nov 18, 2009. (Source: Journal of Mathematical Physics)

On some properties of orthogonal Weingarten functions

Journal of Mathematical Physics — Thu, 19 Nov 2009 16:14:38 +0100

Benoit Collins and Sho Matsumoto We give a Fourier-type formula for computing the orthogonal Weingarten formula. The Weingarten calculus was introduced as a systematic method to compute integrals of polynomials with respect to Haar measure over classical groups. Although a Fourier-type formula was known in the unitary case, the ort ... [J. Math. Phys. 50, 113516 (2009)] published Wed Nov 18, 2009. (Source: Journal of Mathematical Physics)

Efficient calculation of the polarization induced by N coherent laser pulses

Journal of Chemical Physics — Thu, 19 Nov 2009 16:14:37 +0100

Maxim F. Gelin, Dassia Egorova, and Wolfgang Domcke We have developed a novel method, the equation-of-motion phase-matching approach (EOM-PMA), for the calculation of the response of a quantum system to N coherent laser fields. The N-pulse EOM-PMA is limited to weak fields (its domain of validity is equivalent to the traditional nonlinear response fu ... [J. Chem. Phys. 131, 194103 (2009)] published Wed Nov 18, 2009. (Source: Journal of Chemical Physics)

Effects of methanol on nanoparticle self-assembly at liquid-liquid interfaces: A molecular dynamics approach

Journal of Chemical Physics — Thu, 19 Nov 2009 16:14:37 +0100

Mingxiang Luo, Yanmei Song, and Lenore L. Dai Molecular dynamics simulations have been performed to study the influence of methanol on the self-assembly of nanoparticles at liquid-liquid interfaces. The simulation shows that the methanol molecules, at low volume fraction, stay in the aqueous phase but with a preference of the water-trichloroeth ... [J. Chem. Phys. 131, 194703 (2009)] published Wed Nov 18, 2009. (Source: Journal of Chemical Physics)

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Unimolecular decomposition of tetrazine-N-oxide based high nitrogen content energetic materials from excited electronic states

Journal of Chemical Physics — Thu, 19 Nov 2009 16:14:37 +0100

A. Bhattacharya, Y. Q. Guo, and E. R. Bernstein Unimolecular excited electronic state decomposition of novel high nitrogen content energetic molecules, such as 3,3-azobis(6-amino-1,2,4,5-tetrazine)-mixed N-oxides (DAATO), 3-amino-6-chloro-1,2,4,5-tetrazine-2,4-dioxide (ACTO), and 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxde (DATO), is investigated. A ... [J. Chem. Phys. 131, 194304 (2009)] published Wed Nov 18, 2009. (Source: Journal of Chemical Physics)

Emergence of complex behavior in gelling systems starting from simple behavior of single clusters

Journal of Chemical Physics — Thu, 19 Nov 2009 16:14:37 +0100

A. Fierro, T. Abete, and A. Coniglio A theoretical and numerically study of dynamical properties in the sol-gel transition is presented. In particular, the complex phenomenology observed experimentally and numerically in gelling systems is reproduced in the framework of percolation theory, under simple assumptions on the relaxation of ... [J. Chem. Phys. 131, 194906 (2009)] published Wed Nov 18, 2009. (Source: Journal of Chemical Physics)

Interfering pathways in benzene: An analytical treatment

Journal of Chemical Physics — Thu, 19 Nov 2009 16:14:37 +0100

Thorsten Hansen, Gemma C. Solomon, David Q. Andrews, and Mark A. Ratner The mechanism for off-resonant electron transport through small organic molecules in metallic junctions is predominantly coherent tunneling. Thus, new device functionalities based on quantum interference could be developed in the field of molecular electronics. We invoke a partitioning technique to ... [J. Chem. Phys. 131, 194704 (2009)] published Wed Nov 18, 2009. (Source: Journal of Chemical Physics)

A new generic model potential for mesogenic systems: Square well line potential of variable range

Journal of Chemical Physics — Thu, 19 Nov 2009 16:14:37 +0100

Szabolcs Varga and Franz J. Vesely A single-site pair potential is derived to approximate the linear n-site square well interaction. The resulting square well line (SWL) potential is analytical, fairly smooth, and reproduces the distance and orientation dependence of the multisite pair energy. It contains only three control parameter ... [J. Chem. Phys. 131, 194506 (2009)] published Wed Nov 18, 2009. (Source: Journal of Chemical Physics)

Influence of C morphology on high-order harmonic generation enhancement in fullerene-containing plasma

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

R. A. Ganeev, H. Singhal, P. A. Naik, J. A. Chakera, A. K. Srivastava et al. The morphologies of the fullerene targets and the ablated fullerenes to determine the optimal conditions of excitation of the C-containing targets have been analyzed. The optimization of fullerene-containing plasma conditions allowed the enhanced harmonic generation in these plasmas using laser radi ... [J. Appl. Phys. 106, 103103 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

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Comparison between hot spot modeling and measurement of a superconducting hot electron bolometer mixer at submillimeter wavelengths

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

Wei Miao, Yan Delorme, Alexandre Feret, Rolland Lefevre, Benoit Lecomte et al. This paper presents the modeling and measurement of a quasioptical niobium nitride superconducting hot electron bolometer mixer at submillimeter wavelengths. The modeling is performed with a distributed hot spot model which is based on solving a heat balance equation for electron temperature along t ... [J. Appl. Phys. 106, 103909 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

Coupled optoelectronic simulation of organic bulk-heterojunction solar cells: Parameter extraction and sensitivity analysis

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

In this study we consider the OnsagerBraun mechan ... [J. Appl. Phys. 106, 104507 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

Schottky's conjecture on multiplication of field enhancement factors

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

Ryan Miller, Y. Y. Lau, and John H. Booske Of great interest to high power microwave, millimeter wave to terahertz sources, x-ray tubes, electrons guns, etc., is the electric field enhancement obtained from sharp emitting structures fabricated by various microfabrication methods. In this paper, we use conformal mapping to investigate the fie ... [J. Appl. Phys. 106, 104903 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

Energy transfer rates and population inversion of I excited state of Er investigated by means of numerical solutions of the rate equations system in Er:LiYF crystal

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

Laercio Gomes, Andre Felipe Henriques Librantz, Fabio Henrique Jagosich, Wonder Alexandre Luz Alves, Izilda Marcia Ranieri et al. In this work, we present the spectroscopic properties of LiYF (YLF) single crystals activated by high doping of erbium ions. The most important processes that lead to the up-conversion erbium emissions in the infrared region were identified. A time-resolved luminescence spectroscopy technique was em ... [J. Appl. Phys. 106, 103508 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

Enhancement of light transmission by coupling to surface plasmon polaritons of a layer-plus-islands silver layer

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

Pangpang Wang, Dongyan Zhang, Dong Hun Kim, Zhiyong Qiu, Lumei Gao et al. Enhanced light transmission through coupling incident light with surface plasmon polaritons (SPPs) on a layer-plus-islands nanostructure Ag layer, surrounded by symmetric ZnO dielectrics (ZnO/Ag/ZnO), was investigated. The couple and decouple processes at ZnO/Ag and Ag/ZnO grating interfaces were co ... [J. Appl. Phys. 106, 103104 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

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Highly mismatched crystalline and amorphous GaNAs alloys in the whole composition range

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

K. M. Yu, S. V. Novikov, R. Broesler, I. N. Demchenko, J. D. Denlinger et al. Alloying is a commonly accepted method to tailor properties of semiconductor materials for specific applications. Only a limited number of semiconductor alloys can be easily synthesized in the full composition range. Such alloys are, in general, formed of component elements that are well matched in ... [J. Appl. Phys. 106, 103709 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

GeSbTe thin films deposited by pulsed laser: An ellipsometry and Raman scattering spectroscopy study

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

P. Nemec, A. Moreac, V. Nazabal, M. Pavlista, J. Prikryl et al. Pulsed laser (532 nm) deposited GeSbTe thin films were investigated by means of spectroscopic ellipsometry and Raman scattering spectroscopy. TaucLorentz and CodyLorentz models were employed for the evaluation of optical functions of thin films in as-deposited (amorphous) and crystalline (cubic) pha ... [J. Appl. Phys. 106, 103509 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

Strength of lithium fluoride under shockless compression to 114 GPa

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

T. Ao, M. D. Knudson, J. R. Asay, and J.-P. Davis A magnetic loading technique was used to ramp load single-crystal [100] lithium fluoride specimens to peak stresses of 5114 GPa. Wave analysis of in situ particle velocity profiles was used to estimate the compressive strength of LiF at peak stress. It was found that the strength increased with peak ... [J. Appl. Phys. 106, 103507 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

Dielectric response of tantalum oxide subject to induced ion bombardment during oblique sputter deposition

Journal of Applied Physics — Thu, 19 Nov 2009 16:14:36 +0100

We describe the deposition of insulating tantalum oxide thin films under conditions of controlled ion bombardment, which can be achieved using reactive sputtering on 90 degrees off-axis substrates with an applied substrate bias. Capacitive measurements of TaO deposited on unbiased off-axis substrat ... [J. Appl. Phys. 106, 104110 (2009)] published Wed Nov 18, 2009. (Source: Journal of Applied Physics)

Bipolar resistive switching in individual AuNiOAu segmented nanowires

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

Edward D. Herderick, Kongara M. Reddy, Rachel N. Sample, Thomas I. Draskovic, and Nitin P. Padture Evidence for bipolar resistive switching is reported in individual metal-oxide-metal (MOM) nanowires in the system AuNiOAu, and a plausible mechanism for the same is presented. The MOM nanowire architecture may be well suited for much needed fundamental studies of resistive switching because it prov ... [Appl. Phys. Lett. 95, 203505 (2009)] published Tue Nov 17, 2009. (Source: Applied Physics Letters)

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Direct measurement of auger recombination in InGaN/GaN quantum wells and its impact on the efficiency of InGaN/GaN multiple quantum well light emitting diodes

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

M. Zhang, P. Bhattacharya, J. Singh, and J. Hinckley The Auger recombination coefficient in InGaN/GaN quantum wells, emitting at 407 nm has been determined from large signal modulation measurements on lasers in which these quantum wells form the gain region. A value of 1.5 x 10 cm s is determined for the Auger coefficient at room temperature, which i ... [Appl. Phys. Lett. 95, 201108 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Microwave conductance spectra of single-walled carbon nanotube arrays

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

Clark Highstrete, Mark Lee, A. Alec Talin, and Andrew L. Vance Complex conductance spectra of single-walled carbon nanotube (SWCNT) arrays have been measured from 0.1 to 50 GHz at temperatures between 4 and 293 K. Using purely capacitive contacts to separate contact effects from the NTs' response, the intrinsic SWCNT array conductance increased with frequency a ... [Appl. Phys. Lett. 95, 203111 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Aggregates-induced dynamic negative differential resistance in conducting organic films

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

Xian Ning Xie, Junzhong Wang, Kian Ping Loh, and Andrew Thye Shen Wee This letter reports the negative differential resistance (NDR) behavior of perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride films induced by aggregate formation in the film. It is observed that aggregate-states in the energy gap can by-pass the common charge conduction mode, and electron injec ... [Appl. Phys. Lett. 95, 203302 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Electronic properties and open-circuit voltage enhancement in mixed copper phthalocyanine:fullerene bulk heterojunction photovoltaic devices

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

T. W. Ng, M. F. Lo, M. K. Fung, S. L. Lai, Z. T. Liu et al. While bulk heterojunctions (HJ) have been used in organic photovoltaic (OPV) devices, there are few studies on their interface electronics and mechanisms on device performance. Here, we studied the electronic structure of a mixed CuPc:C and a discrete CuPc/C junctions using photoemission spectroscop ... [Appl. Phys. Lett. 95, 203303 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Charge transport in polypyrrole:ZnO-nanowires composite films

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

A. Singh, Aditee Joshi, S. Samanta, A. K. Debnath, D. K. Aswal et al. Low temperature electrical transport properties of composite polypyrrole (PPy) films having ZnO-nanowires (ZnONWs) in the range of 050 wt. % have been investigated. It has been found that pure PPy film is in the critical regime of the metal-to-insulator transition, and adding ZnONWs drive composite ... [Appl. Phys. Lett. 95, 202106 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

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Fabrication of a transparent and flexible thin film transistor based on single-walled carbon nanotubes using the direct transfer method

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

S. H. Tseng and N. H. Tai The fabrication of transparent and flexible thin film transistors (TFTs), using single-walled carbon nanotube (SWCNT) networks as bottom gates and conducting channels and polymethylmethacrylate (PMMA) as an insulating layer, by the direct transfer method is demonstrated. The fabricated SWCNT-TFTs ex ... [Appl. Phys. Lett. 95, 204104 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Preparation of monodisperse emulsions by hydrodynamic size fractionation

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

We describe a microfluidic system allowing fast and efficient size-dependent separation of droplets using hydrodynamics. This system allows efficient fractionation of droplets with a difference in volume as small as 2.33-fold (corresponding to a 1.33-fold difference in diameter of spherical droplets ... [Appl. Phys. Lett. 95, 204103 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Shape-dependent nonlinear absorption and relaxation in CuInS nanocrystals

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

We report the observation of nonlinear-optical response and relaxation in copper indium sulfide (CuInS) crystalline nanoparticles and nanorods with femtosecond Z-scans and transient absorption measurements. Dependent on the size and shape, two-photon absorption and saturation in the one-photon absor ... [Appl. Phys. Lett. 95, 201109 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Visualization of highly graded oxygen vacancy profiles in lead-zirconate-titanate by spectrally resolved cathodoluminescence spectroscopy

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

Atsuo Matsutani, Zhenhua (Jerry) Luo, Soodkhet Pojprapai, Mark Hoffman, and Giuseppe Pezzotti The ultraviolet and visible cathodoluminescence (CL) emitted at room temperature from bulk hard lead-zirconate-titanate polycrystalline perovskite has been systematically collected before and after an annealing cycle conducted in a reducing atmosphere. Spectroscopic assessments have been made of the ... [Appl. Phys. Lett. 95, 202903 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Sound control by temperature gradients

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

Jose Sanchez-Dehesa, Mitko I. Angelov, Francisco Cervera, and Liang-Wu Cai This work reports experiments showing that airborne sound propagation can be controlled by temperature gradients. A system of two heated tubes is here used to demonstrate the collimation and focusing of an ultrasonic beam by the refractive index profile created by the temperature gradients existing ... [Appl. Phys. Lett. 95, 204102 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

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Josephson effects in weakly coupled MgB intergrain nanobridges prepared by focused ion beam

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

Soon-Gul Lee, Sung-Hak Hong, Won Kyung Seong, and Won Nam Kang We have fabricated weakly coupled intergrain nanobridges from MgB films by a focused ion beam (FIB) patterning technique and studied their transition properties. The bridges were nominally 300 nm wide and 100 nm long, and crossed a single grain boundary perpendicularly. The temperature-dependent res ... [Appl. Phys. Lett. 95, 202504 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Terahertz lasing from silicon by infrared Raman scattering on bismuth centers

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

S. G. Pavlov, U. Bottger, R. Eichholz, N. V. Abrosimov, H. Riemann et al. Stimulated emission at terahertz frequencies (4.55.8 THz) has been realized by electronic Raman scattering of infrared radiation on bismuth donor centers in silicon at low temperatures. The Stokes shift of the observed laser emission is 40.53 meV which corresponds to the bismuth intracenter transiti ... [Appl. Phys. Lett. 95, 201110 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Nonvolatile memory with CoSiO core-shell nanocrystals as charge storage nodes in floating gate

Applied Physics Letters — Thu, 19 Nov 2009 16:14:26 +0100

Hai Liu, Domingo A. Ferrer, Fahmida Ferdousi, and Sanjay K. Banerjee In this letter, we reported nanocrystal floating gate memory with CoSiO core-shell nanocrystal charge storage nodes. By using a water-in-oil microemulsion scheme, CoSiO core-shell nanocrystals were synthesized and closely packed to achieve high density matrix in the floating gate without aggregation ... [Appl. Phys. Lett. 95, 203112 (2009)] published Wed Nov 18, 2009. (Source: Applied Physics Letters)

Photowritten high-Q cavities in two-dimensional chalcogenide glass photonic crystals

Optics Letters — Thu, 19 Nov 2009 16:13:54 +0100

We demonstrate a high-Q(~125,000) photonic crystal (PhC) cavity formed using a postprocessing optical exposure technique where the refractive index of a photosensitive chalcogenide PhC is modified locally. The evolution of the cavity resonances was monitored in situ during writing using a tapered ... (Source: Optics Letters)

Spectroscopic phase microscopy for quantifying hemoglobin concentrations in intact red blood cells

Optics Letters — Thu, 19 Nov 2009 16:13:54 +0100

We report a practical method for label-free quantification of specific molecules using spectroscopic imaging of sample-induced phase shifts. Diffraction phase microscopy equipped with various wavelengths of light source is used to record wavelength-dependent phase images. We first perform ... (Source: Optics Letters)

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Modeling of Z-scan characteristics for one-dimensional nonlinear photonic bandgap materials

Optics Letters — Thu, 19 Nov 2009 16:13:54 +0100

We propose a Z-scan theory for one-dimensional nonlinear photonic bandgap materials. The Z-scan characteristics for this material are analyzed. Results show that the Z-scan curves for photonic bandgap materials with nonlinear refraction are similar to those of uniform materials exhibiting both ... (Source: Optics Letters)

Numerical model for the temporal broadening of optical pulses propagating through weak atmospheric turbulence

Optics Letters — Thu, 19 Nov 2009 16:13:54 +0100

In atmospheric optical communications, propagating pulses may be influenced by pulse spreading owing to turbulence, above all in scenarios characterized by sand and/or dust atmosphere. The long-term temporal broadening of a space-time Gaussian pulse propagating along a horizontal path through weak ... (Source: Optics Letters)

Full phase and amplitude control in computer-generated holography

Optics Letters — Thu, 19 Nov 2009 16:13:53 +0100

We report what we believe to be the first realization of a computer-generated complex-valued hologram recorded in a single film of photoactive polymer. Complex-valued holograms give rise to a diffracted optical field with control over its amplitude and phase. The holograms are generated by a ... (Source: Optics Letters)

Continuous-wave sum-frequency generation in AlGaAs Bragg reflection waveguides

Optics Letters — Thu, 19 Nov 2009 16:13:53 +0100

Efficient sum-frequency generation in epitaxial GaAs/AlGaAs waveguides is reported. Phase matching is achieved for type II nonlinear interaction using Bragg reflection waveguides. Continuous-wave signal and pump in 1550 nm wavelength window were used for upconversion of photons to the 775 nm ... (Source: Optics Letters)

Low-power operation of vertically aligned liquid-crystal system via anatase-TiO_2 nanoparticle dispersion

Optics Letters — Thu, 19 Nov 2009 16:13:53 +0100

Electro-optic performance of a liquid-crystal (LC) system is enhanced by TiO_2 nanoparticle dispersed in nematic liquid crystal (NLC). The 2.5 V threshold voltage of LC for device operation is lowered to 0.5 V through TiO_2 nanoparticle mixing up to 2 wt.%. To characterize the shape and size ... (Source: Optics Letters)

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Correct self-assembling of spatial frequencies in super-resolution synthetic aperture digital holography

Optics Letters — Thu, 19 Nov 2009 16:13:53 +0100

Synthetic aperture enlargement is obtained, in lensless digital holography, by introducing a diffraction grating between the object and the CCD camera with the aim of getting super-resolution. We demonstrate here that the spatial frequencies are naturally self-assembled in the reconstructed image ... (Source: Optics Letters)

Closed-loop carrier-envelope phase stabilization with an acousto-optic programmable dispersive filter

Optics Letters — Thu, 19 Nov 2009 16:13:53 +0100

We demonstrate arbitrary carrier-envelope (CE) phase control of femtosecond laser pulses by an acousto-optic programmable dispersive filter (AOPDF), with an accuracy better than π/100 at a repetition rate of 1 kHz. We also demonstrate, for the first time to the best of our knowledge, 15 Hz ... (Source: Optics Letters)

Three-photon-induced four-photon absorption and nonlinear refraction in ZnO quantum dots

Optics Letters — Thu, 19 Nov 2009 16:13:53 +0100

Three-photon-induced four-photon absorption via excited-state absorption and self-defocusing nonlinear refraction are reported for the first time, to our knowledge, in ZnO quantum dots with average sizes of 2.0+/-0.1 nm with 1064 nm radiation from a Q-switched Nd:YAG laser at a peak intensity of ... (Source: Optics Letters)

Nondiffracting wave properties in radially and azimuthally symmetric optical axis phase plates

Optics Letters — Thu, 19 Nov 2009 16:13:53 +0100

A wave propagation analysis carried out in two kinds of q-plates having topological unit charge (1-plates), one plate with a radial orientation of the optical axis and the other with an azimuthal one, reveals that these devices admit nondiffracting Bessel beams as exact solutions of the vector ... (Source: Optics Letters)

Study of reflection gratings recorded in polyvinyl alcohol/acrylamide-based photopolymer

Applied Optics — Thu, 19 Nov 2009 16:13:52 +0100

High-spatial-frequency fringes associated with reflection holographic optical elements are difficult to obtain with currently available recording materials. In this work, holographic reflection gratings were stored in a polyvinyl alcohol/acrylamide photopolymer. This material is formed of ... (Source: Applied Optics)

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New Netbook by Recyclable Materials and with Less Heat Dissipation

PhysicsWeb Products & Press — Thu, 19 Nov 2009 15:59:02 +0100

This netbook is made of recyclable materials and it adopt the new technologies for less heat dissipation. (Source: PhysicsWeb Products & Press)

Photo finish in race for strontium condensate

PhysicsWeb News — Thu, 19 Nov 2009 15:55:03 +0100

Isotope’s scattering length is ‘just right’ (Source: PhysicsWeb News)

UK to pull out of Gemini Observatory

PhysicsWeb News — Thu, 19 Nov 2009 14:28:13 +0100

Funding is 'almost certain' to stop after 2012 (Source: PhysicsWeb News)

Thermo-optic controllable hybrid photonic polymers containing inorganic nanoparticles

Journal of the Optical Society of America B — Thu, 19 Nov 2009 05:00:00 +0100

In order to control thermo-optic (T-O) coefficient of polymer materials, a hybrid polymer system with inorganic nanoparticles was examined. Because polymer materials have high T-O coefficient with low refractive index and inorganic materials have low T-O coefficient with high refractive index, we ... (Source: Journal of the Optical Society of America B)