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951.
Ling-Ling Xing 《Journal of Physics and Chemistry of Solids》2008,69(9):2341-2343
Using the assumption δT=δT0(V/V0)k and the Grüneisen parameter γ macroscopic definition expression, we obtained a relationship for the volume dependence of the Grüneisen parameter γ. We have calculated the Grüneisen parameter γ with this relationship for NaCl and ε-Fe at high pressure under study. The calculated values of γ are found to show fairly in good agreement with available experimental data. 相似文献
952.
Yejin Zhang Wanhua Zheng Mingxin Xing Gang Ren Hailing Wang LiangHui Chen 《Optics Communications》2008,281(10):2774-2778
The exact calculation of mode quality factor Q is a key problem in the design of high-Q photonic crystal nanocavity. On the basis of further investigation on conventional Pade approximation, FDM and DFT, Pade approximation with Baker’s algorithm is enhanced through introducing multiple frequency search and parabola interpolation. Though Pade approximation is a nonlinear signal processing method and only short time sequence is needed, we find the different length of sequence requirements for 2D and 3D FDTD, which is very important to obtain convergent and accurate results. By using the modified Pade approximation method and 3D FDTD, the 2D slab photonic crystal nanocavity is analyzed and high-Q multimode can be solved quickly instead of large range high-resolution scanning. Monitor position has also been investigated. These results are very helpful to the design of photonic crystal nanocavity devices. 相似文献
953.
We study spin-dependent shuttle phenomena in a nanoelectromechanical single electron transistor (NEM-SET) with magnetic leads by considering the coupling between the transport of spin-polarized electrons and mechanical oscillations of the nanometer quantum dot. It is shown that there are two different bias-voltage thresholds for the shuttle instability in electronic transport through the NEM-SET, respectively, corresponding to parallel (P) and antiparallel (AP) magnetization alignments. In between the two thresholds, the electronic transport is in the shuttling regime for the P alignment but in the tunneling regime for the AP one, resulting in a very large spin valve effect. 相似文献
954.
We study the organization of topological defects in a system of nematogens confined to the two-dimensional sphere (S2). We first perform Monte Carlo simulations of a fluid system of hard rods (spherocylinders) living in the tangent plane of S2. The sphere is adiabatically compressed until we reach a jammed nematic state with maximum packing density. The nematic state exhibits four +1/2 disclinations arrayed on a great circle. This arises from the high elastic anisotropy of the system in which splay (K1) is far softer than bending (K3). We also introduce and study a lattice nematic model on S2 with tunable elastic constants and map out the preferred defect locations as a function of elastic anisotropy. We find a one-parameter family of degenerate ground states in the extreme splay-dominated limit K_{3}/K_{1}-->infinity. Thus the global defect geometry is controllable by tuning the relative splay to bend modulus. 相似文献
955.
The properties of multiply charged anions are dominated by intramolecular Coulomb repulsion (ICR). Using photoelectron imaging, we show the effect of ICR on photoelectron angular distributions for a series of dianions, -O2C(CH2)_{n}CO_{2};{-} (D_{n};{2-}). The observed photoemission band of D_{n};{2-} was due to a perpendicular transition from the charged end group. However, photoemission intensities were observed to peak along the laser polarization for smaller n due to the strong ICR that forces electrons to be emitted along the molecular axis. This emission pattern weakens with increasing n and at D112- the angular distribution reverses back to peak at the perpendicular direction due to the reduced ICR. 相似文献
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959.
YAO Zhen-Zhi ZHANG Chun-Yi ZHU Hong-Wu MENG Xiang-Hua LU Xing SHAN Wen-Rui TIAN Bo 《理论物理通讯》2008,49(5):1125-1128
In this paper, we derive the bilinear form for a variable-coefficient Kadomtsev Petviashvili-typed equation. Based on the bilinear form, we obtain the Wronskian determinant solution, which is proved to be indeed an exact solution of this equation through the Wronskian technique. In addition, we testify that this equation can be reduced to a Jacobi identity by considering its solution as a Grammian determinant by means of Pfaffian derivative formulae. 相似文献
960.
Photocatalytic activity of Nb2O5/SrNb2O6 heterojunction on the degradation of methyl orange 总被引:1,自引:0,他引:1
Jingcheng Xing Zhichao Shan Jianjiang Bian Wendeng Wang 《Journal of Physics and Chemistry of Solids》2008,69(1):23-28
The pure SrNb2O6 powders were prepared at 1400 °C by a conventional solid-state method and characterized by X-ray powder diffraction and UV-vis diffuse reflection spectrum. The powders of Nb2O5 and SrNb2O6 were ball-milled together and annealed to form the Nb2O5/SrNb2O6 composite. Photocatalytic activities of the composites were investigated on the degradation of methyl orange. The results show that the proportion of Nb2O5 to SrNb2O6 and the annealing temperature greatly influence the photocatalytic activities of the composites. The best photocatalytic activity occurs when the weight proportion of Nb2O5 to SrNb2O6 is 30% and the annealing temperature is 600 °C. The tremendously enhanced photocatalytic activity of the Nb2O5/SrNb2O6 composite compared to Nb2O5 or SrNb2O6 is ascribed to the heterojunction effect taking place at the interface between particles of Nb2O5 and SrNb2O6. The powders also show a higher photocatalytic activity than commercial anatase TiO2. 相似文献