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Journal of Applied Physics : Simulation of the bulk and surface mo...

By: M. A. Shapiro, K. R. Samokhvalova, J. R. Sirigiri, R. J. Temkin, and G. Shvets

Description: We present a numerical study of the electromagnetic properties of the three-dimensional metallic wire lattices operating at microwave frequencies with applications to advanced accelerating structures and microwave sources. The metallic lattices can be considered as “artificial plasmas” because they demonstrate the properties of plasmas with a negative dielectric constant. Bulk modes in a diamond lattice of metal wires and surface modes on its interface are c...

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Review of Scientific Instruments : A broadband absorption spectrom...

By: Justin M. Langridge, Stephen M. Ball, Alexander J. L. Shillings, and Roderic L. Jones

Description: A broadband absorption spectrometer has been developed for highly sensitive and target-selective in situ trace gas measurements. The instrument employs two distinct modes of operation: (i) broadband cavity enhanced absorption spectroscopy (BBCEAS) is used to quantify the concentration of gases in sample mixtures from their characteristic absorption features, and (ii) periodic measurements of the cavity mirrors’ reflectivity are made using step-scan phase shi...

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Applied Physics Letters : Directing the transportation of a water ...

By: Qian Feng Xu, Jian Nong Wang, Ian H. Smith, and Kevin D. Sanderson

Description: Directional transportation of a ball-like water droplet on a superhydrophobic (SH) surface has been experimentally demonstrated. A SH surface with a water contact angle of as high as 160° and a sliding angle close to 0° is prepared by a sol-gel method based on removable polymeric nanospheres. A designed path line is then created on the prepared SH surface. The contact angle possesses anisotropy on the patterned SH surface. When the tilted angle of the patter...

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Journal of Mathematical Physics : Lp-uniform attractor for nonauto...

By: Xingjie Yan and Chengkui Zhong

Description: The goal of this paper is to consider the asymptotic behavior of solutions of nonautonomous classical reaction-diffusion equations in unbounded domains with nonlinearity having a polynomial growth of arbitrary order. The existence and structure of a uniform attractor are obtained in the spaces L2(n) and Lp(n), respectively.

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Biblioteca Hispanica : Programme Lessons of a Course of Natural Hi...

By: Emilio Ribera Gomez
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Chaos : On the bifurcation of species

By: M.A.Bees,P.H.Coullet, and E.A.Spiegel

Description: We propose and analyze a model of evolution of species based upon a general description of phenotypes in terms of a single quantifiable characteristic. In the model, species spontaneously arise as solitary waves whose members almost never mate with those in other species, according to the rules laid down. The solitary waves in the model bifurcate and we interpret such events as speciation. Our aim in this work is to determine whether a generic mathematical m...

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Chaos : Winnerless competition principle and prediction of the tra...

By: Valentin Afraimovich, Irma Tristan, Ramon Huerta, and Mikhail I. Rabinovich

Description: Predicting the evolution of multispecies ecological systems is an intriguing problem. A sufficiently complex model with the necessary predicting power requires solutions that are structurally stable. Small variations of the system parameters should not qualitatively perturb its solutions. When one is interested in just asymptotic results of evolution (as time goes to infinity), then the problem has a straightforward mathematical image involving simple attrac...

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Journal of Applied Physics : Characterization of dilute InPN layer...

By: T. D. Das, S. Dhar, and B. M. Arora

Description: We have grown dilute InPN layers by liquid phase epitaxy and characterized them using high resolution x-ray diffraction, optical absorption, low temperature photoluminescence, and Hall measurement techniques. Our results indicate that a maximum amount of 0.2% nitrogen has been incorporated in the material with a band gap lowering consistent with expectations. The crystalline quality of the material is found to improve upon nitrogen incorporation. Large incre...

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The Journal of Chemical Physics : Precision shooting: Sampling lon...

By: Michael Grünwald, Christoph Dellago, and Phillip L. Geissler

Description: The kinetics of collective rearrangements in solution, such as protein folding and nanocrystal phase transitions, often involve free energy barriers that are both long and rough. Applying methods of transition path sampling to harvest simulated trajectories that exemplify such processes is typically made difficult by a very low acceptance rate for newly generated trajectories. We address this problem by introducing a new generation algorithm based on the lin...

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Journal of Applied Physics : Acoustic anisotropy in uniaxial tungs...

By: Jae-Hyeon Ko, S. G. Lushnikov, Do Han Kim, Seiji Kojima, Byeong-Eog Jun et al

Description: Acoustic properties were investigated for four tungsten bronze (TB) uniaxial ferroelectric crystals, i.e., (Sr0.61Ba0.39)5Nb10O30 (SBN61), Cu-doped (K0.5Na0.5)1.0(Sr0.75Ba0.25)4.5Nb10O30 (KNSBN:Cu), K5.80Li3.82Nb10.12O30, and K4.74Li3.07Nb10.44O30 of which the spontaneous polarization is directed along the polar c axis. Large acoustic anisotropy between the two elastic constants C11 and C33 have been observed from all samples. C33 exhibits a significant soft...

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Journal of Applied Physics : Dynamics of optically injected two-di...

By: E. Ya. Sherman, R. M. Abrarov, and J. E. Sipe

Description: We investigate the charge and spin dynamics of optically injected currents in multiple quantum well structures using a hydrodynamic model. The dynamics is very complex even on time scales of the order of 1 ps due to the interplay of Coulomb forces, electron-hole drag effects, and nonlinearity of the equations of motion. Our analysis is based on a numerical approach employing an expansion of the calculated quantities in a Hermite–Gaussian basis. We calculate ...

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Journal of Applied Physics : Microwave dielectric and Raman scatte...

By: K. Sudheendran, K. C. James Raju, Manoj K. Singh, and Ram S. Katiyar

Description: Bismuth zinc niobate (Bi1.5Zn1.0Nb1.5O7) thin films were deposited on fused silica substrates by pulsed laser deposition. Its phase composition and microstructure were characterized by x-ray diffraction and atomic force microscopy. The as deposited films were amorphous and all of them were crystallized after a postdeposition annealing at 600 °C for 30 min in air. The crystallite size of the films was found to be varying between 31 and 60 nm with respect to t...

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Journal of Mathematical Physics : The effect of classical noise on...

By: Jean-Philippe Aguilar and Nils Berglund

Description: We consider a quantum two-level system perturbed by classical noise. The noise is implemented as a stationary diffusion process in the off-diagonal matrix elements of the Hamiltonian, representing a transverse magnetic field. We determine the invariant measure of the system and prove its uniqueness. In the case of Ornstein–Uhlenbeck noise, we determine the speed of convergence to the invariant measure. Finally, we determine an approximate one-dimensional dif...

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The Journal of Chemical Physics : Analysis of polyatomic molecules...

By: Peter C. Chen and Kamilah Mitchell

Description: The peak-sorting capabilities of high resolution coherent two-dimensional (2D) spectroscopy provide a new way of dealing with severe rotational congestion. This paper describes the application of this technique to the polyatomic molecule, NO2. NO2 is a primary component of photochemical smog and has a notoriously complex and congested spectrum that extends from the infrared to the ultraviolet regions. This spectrum is infamous for having an unusually high de...

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Applied Physics Letters : Subwavelength imaging of acoustic waves ...

By: Zhaojian He, Feiyan Cai, Yiqun Ding, and Zhengyou Liu

Description: In this letter, the subwavelength imaging of acoustic waves is reported based on a mechanism that the evanescent modes of a source are canalized by the Bloch modes of a two-dimensional phononic crystal that served as the lens. The phononic crystal was designed to have a thickness that meets the condition of Fabry–Pérot resonance in order to enhance wave transmission and hence to improve imaging performance. Numerical simulations demonstrated that for a point...

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Biblioteca Hispanica : Programme Notions of Natural History with P...

By: Candido Rivers and Rial
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Journal of Mathematical Physics : Discrete approximation of quantu...

By: Luc Bouten and Ramon Van Handel

Description: We develop a general technique for proving convergence of repeated quantum interactions to the solution of a quantum stochastic differential equation. The wide applicability of the method is illustrated in a variety of examples. Our main theorem, which is based on the Trotter–Kato theorem, is not restricted to a specific noise model and does not require boundedness of the limit coefficients.

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Physics of Plasmas : Quantum and plasma screening effects on the W...

By: Young-Dae Jung and Daiji Kato

Description: The quantum and plasma screening effects on the Wannier threshold law for the double-electron escape are investigated in strongly coupled semiclassical plasmas. The renormalized electron charge and Wannier exponent are obtained by considering the equation of motion in the Wannier configuration with the screened pseudopotential model as functions of the de Broglie wavelength, Debye length, and charge of the residual ion. It is shown that the renormalized elec...

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Physics of Plasmas : Spectroscopic study on rotational and vibrati...

By: Xiao-Jiang Huang, Yu Xin, Lei Yang, Quan-Hua Yuan, and Zhao-Yuan Ning

Description: By using optical emission spectroscopy, the vibrational and rotational temperatures of N2 and N2+ in capacitively coupled plasma (CCP) discharges driven by dual-frequency 41 MHz and 2 MHz are investigated. The vibrational and rotational temperatures are measured based on the N2+ first negative system and N2 second positive system overlapped molecular emission optical spectrum, using the method of comparing the measured and calculated spectra with a least-squ...

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Journal of Applied Physics : Ion transport in polyacetylene ionomers

By: Fuding Lin, Yongjun Wang, and Mark Lonergan

Description: Ion transport in cationically and anionically functionalized polyacetylene ionomers, PAC and PAA, respectively, was investigated by analyzing the impedance responses of thin film Au∣ionomer∣Au sandwich configurations. Samples were measured over a frequency range of 10−2–106 Hz and a temperature range of 298–398 K. Electrode polarization at low frequencies and dispersion due to ion hopping at higher frequencies were observed. The impedance data were analyzed ...

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