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Description: The collective backscattering of intense laser radiation by energetic electron beams is considered. Exact solutions for the radiation field are obtained, for arbitrary electron pulse shapes and laser intensities. The electron beams act as imperfect nonlinear mirrors on the incident laser radiation. This collective backscattering process can lead to the development of new sources of ultrashort pulse radiation in the gamma-ray domain. Numerical examples show t...
Description: The renormalization group (RG) method for differential equations is one of the perturbation methods for obtaining approximate solutions. This article shows that the RG method is effectual for obtaining an approximate center manifold and an approximate flow on it when applied to equations having a center manifold.
Description: Recent estimates of the CCSD(T)(FC) limit for the neon atom (−128.8690±0.001 and −128.8687±0.0005 hartree) are refined. Re-examination of the basis set convergence of the separate self-consistent field, MP2-αβ, MP2-αα, CCSD–MP2, and (T) components of the valence CCSD(T) energy gives a complete basis set limit of −128.869 236±0.000 02 hartree. This can now be used as an improved benchmark to calibrate more approximate calculations.
Description: DC and bipolar voltage stresses are used to isolate mechanical degradation of the movable electrode from charging mechanism in microelectromechanical capacitive switches. Switches with different metals as the movable electrode were investigated. In titanium switches, a shift in the pull-in voltages is observed after dc stressing whereas no shift occurs after the bipolar stressing, which is to be expected from charging theory. On switches with similar dielect...
Description: The bubble formation sites in film boiling are the nodes of the instability occurring at the liquid-vapor interface. We perform a linear stability analysis with a time dependent base state, accounting for the growth of the film due to evaporation, in order to identify the most dominant wavelength. Choosing a domain size of five times the wavelength predicted by Berenson [ASME J. Heat Transfer 83, 351 (1961) ] and an initial liquid-vapor interface profile hav...
Description: A theoretical study of vibrational spectral diffusion and hydrogen bond dynamics in aqueous ionic solutions is presented from first principles without employing any empirical potential models. The present calculations are based on ab initio molecular dynamics for trajectory generation and wavelet analysis of the simulated trajectories for time dependent frequency calculations. Results are obtained for two different deuterated aqueous solutions: the first one...
Description: The microstructural and magnetic properties of amorphous, nanoclustered, and self-organized bilayer Nd0.5Sr0.5MnO3 films, prepared by rf magnetron sputtering, are investigated. The amorphous film was found to be a typical paramagnet with free motion of the individual Mn spins, and the magnetic properties are well described on the basis of the Curie–Weiss approximation. The nanoclustered film manifests magnetic properties mimicking those of superparamagnetic ...
Description: The effects of chemical order on the phase stability and magnetic properties of the metamagnetic shape memory alloy Ni45Co5Mn36.7In13.3 were investigated. Alloys quenched from the B2 and L21 phase regions were found to transform to the L10 and 6M martensite phases, respectively. For alloys quenched from the B2 region the martensitic transformation starting temperature is about 80 K higher than that for alloys quenched from the L21 region. The Curie temperatu...
Description: Remotely doped In0.35Ga0.65As layers of different coverages 6, 9, 11, and 13 ML were grown by molecular beam epitaxy on (100) GaAs. Quantum dot (QD) nucleation was observed in situ by reflection high-energy electron diffraction at 8 ML growth of In0.35Ga0.65As, while for 6 ML, only two-dimensional (2D) growth was observed. Atomic force microscopy, low temperature photoluminescence, and Hall effect measurements confirmed this transition from 2D to three-dimen...
Description: This study aims to investigate the effect of viscosity of the base fluid on the thermal conductivity of nanofluids in which Fe3O4 nanoparticles are suspended in the base fluid composed of diesel oil and polydimethylsiloxane. Viscosity of the base fluid is varied by changing the volumetric fractions between both fluids. The measured thermal conductivity of nanofluids gradually approaches the value predicted by the Maxwell equation by increasing the viscosity....
Description: In this work a μ =−1 metamaterial MM lens for magnetic resonance imaging MRI is demonstrated. MRI uses surface coils to detect the radio frequency rf energy absorbed and emitted by the nuclear spins in the imaged object. The proposed MM lens manipulates the rf field detected by these surface coils so that the coil sensitivity and spatial localization are substantially improved. Beyond this specific application, we feel that the reported results are th...
Description: Nanoparticles of GdVO4 doped with Eu3+ and core/shell of GdVO4:Eu3+/GdVO4 are prepared by urea hydrolysis method using ethylene glycol as capping agent as well as reaction medium at 130 °C. Unit cell volume increases when GdVO4 is doped with Eu3+ indicating the substitution of Gd3+ lattice sites by Eu3+. From luminescence study, it is confirmed that there is no particle size effect on emission positions of Eu3+. Optimum luminescence intensity is found to be ...
Description: This paper provides a quantitative comparison and explores the design space of lead zirconium titanate (PZT)–only and PZT-on-silicon length-extensional mode resonators for incorporation into radio frequency microelectromechanical system filters and oscillators. We experimentally measured the correlation of motional impedance (RX) and quality factor (Q) with the resonators’ silicon layer thickness (tSi). For identical lateral dimensions and PZT-layer thicknes...
Description: To eliminate compositional and size variabilities between individual binary nanoparticles, it is essential to control the mechanistic steps involved in nanoparticle synthesis. A common method for synthesizing FePt nanoparticles involves the simultaneous decomposition and reduction in iron and platinum precursors, respectively. This simultaneous nucleation and growth method yields wide composition and size distributions. This paper describes and experimentall...
Description: Thermal diffusion or Soret effect is a phenomenon of mass transport in fluid mixtures driven by temperature gradients. In this paper, we have studied thermal diffusion coefficients for different binary n-alkane mixtures (equal mass fraction) through both theoretical and experimental methods. The theoretical model is based on the irreversible thermodynamics. Particularly, the nonequilibrium thermodynamic property τ is examined and remodeled with a considerati...
Description: A point-plane electrode system in atmospheric air is established to investigate the mechanism of the corona discharge. By using this system, the current pulses of the corona discharges under the 50 Hz ac voltage are measured using partial discharge (PD) measurement instrument and constitute the point-plane voltage-current (V-I) characteristic equation together with the voltage. Then, this paper constructs the nonlinear circuit model and differential equation...