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991.
Polarized spin transport in mesoscopic quantum rings with electron--phonon and Rashba spin--orbit coupling 下载免费PDF全文
The influence of electron--phonon (EP) scattering on spin
polarization of current output from a mesoscopic ring with Rashba
spin--orbit (SO) interaction is numerically investigated. There are
three leads connecting to the ring at different positions;
unpolarized current is injected to one of them, and the other two
are output channels with different bias voltages. The spin
polarization of current in the outgoing leads shows oscillations as a
function of EP coupling strength owing to the quantum interference
of EP states in the ring region. As temperature increases, the
oscillations are evidently suppressed, implying decoherence of
the EP states. The simulation shows that the magnitude of polarized
current is sensitive to the location of the lead. The polarized
current depends on the connecting position of the lead in a
complicated way due to the spin-sensitive quantum interference
effects caused by different phases accumulated by transmitting
electrons with opposite spin states along different paths. 相似文献
992.
993.
994.
考虑自重载荷作用的连续体结构拓扑优化 总被引:2,自引:0,他引:2
针对自重载荷作用下连续体结构拓扑优化中常遇到的柔顺度随单元密度变化的非单调性、非有效的材料体积约束和材料低密度区出现的``附属'效应等主要困难,提出了RAMP材料插值模型和平均敏度过滤技术相结合的求解策略,并采用MMA方法进行了优化求解. 研究了惩罚因子的选择对最优拓扑以及材料体积约束的影响. 结果表明,合理增大RAMP材料模型中惩罚因子(例如取值达到20.0), 可使材料体积约束达到有效约束. 此外,通过与Sigmund提出的敏度过滤技术比较表明,当引入平均敏度过滤技术时,结果0/1化程度较Sigmund的敏度技术高,可获得清晰的黑白拓扑. 相似文献
995.
Jianyong Huang Tao Zhu Lei Qin Xiaoling Peng Chunyang Xiong Jing Fang 《Acta Mechanica Solida Sinica》2009,22(6):563-570
Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency cellular traction recovery. By applying a gradient-based digital image correlation method to track randomly distributed fluorescence microbeads on the deformed substrate induced by single cardiac myocyte, high-resolution substrate displacement field can readily be obtained. By using a numerical algorithm based on the integral Boussinesq solution, cell-substrate tractions are reconstructed in a stable and reliable manner. Finally, spatiotemporal dynamics of a single cardiac myocyte is investigated as it adheres to a polyacrylamide elastic substrate. 相似文献
996.
997.
Bubble generation and transport in a micro-device composed of a micro-T-junction and a following serpentine micro-channel was experimentally investigated. It has a rectangular cross-sectional with an aspect ratio of 7.425. Air and water were used as gas and liquid, respectively. Mixtures of water–glycerol and water–Tween-20 were used to study the effects of liquid viscosity and surface tension. Compared with previous T-junction bubble generation, the liquid and gas inlets orientation was switched in this work. The continuous flow was driven from the perpendicular channel and the dispersion flow was from the main channel. It shows that the break-up process has three periodic steps under certain operating conditions. The dimensionless bubble length L/w in the micro-channel with high aspect ratio is much larger than that in square microchannels. A correlation is proposed to correlate L/w with liquid flow rate JL, gas flow rate JG, and liquid viscosity μL. Surface tension σ can change the bubble shape but almost does not affect the bubble length in this fast break-up process. Additionally, a long bubble may be broken up at the corners at the same time because the locations of gas and liquid are exchanged relative to the concave and convex portions of an elbow after a turn which may result in the change of fluid velocities and gas–liquid pressure drop. 相似文献
998.
提出光滑分子动力学方法(SMD)的并行化计算方法,编制光滑分子动力学以及光滑分子动力学-分子动力学(SMD-MD)耦合的并行程序,并分析铜纳米单晶的单向拉伸和带裂纹板的拉伸问题.光滑分子动力学在分子动力学基础上引入背景网格,在背景网格点上求解运动方程,由此将控制MD临界时间步长的因素化为背景网格单元尺寸,扩大可用的时间积分步长,缩短总计算时间.通过单晶拉伸和带裂纹板拉伸等较大规模问题的计算,验证方法的正确性.与传统分子动力学相比,SMD和SMD-MD耦合方法可以节约计算时间. 相似文献
999.
A low cost spin coating route of fabricating CuInS2 polycrystalline thin films by reactive sin-tering method was put forward. The ink for spin coating was optimized by pre-reducing the precursor powders in hydrogen, which turned the nanoparticle precursor powders from mixed sulfides into a mixture of CuInS2 and Cu-In metal alloys. The results of scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Raman spectra showed that this optimization could highly improve the performance of CuInS2 polycrystalline thin films, including higher packing density, less impurity phases, and better quality. The en-ergy gap of optimized CuInS2 thin film was determined to be about 1.45 eV by absorption spectroscopy measurement. 相似文献
1000.
Influence of local environment on the intensity of the localized surface plasmon polariton of Ag nanoparticles 下载免费PDF全文
A combined Ag nanoparticle with an insulating or conductive
layer structure has been designed for molecular detection using
surface enhanced Raman scattering microscopy. Optical absorption
studies revealed localized surface plasmon resonance, which shows
regular red shift with increasing environmental dielectric
constant. With the combined structure of surface enhanced Raman
scattering substrates and rhodamine 6G as a test molecule, the
results in this paper show that the absorption has a linear
relationship with the local electromagnetic field for insulating
substrates, and the electrical property of the substrate has a
non-negligible effect on the intensity of the local electromagnetic
field and hence the Raman enhancement. 相似文献