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排序方式: 共有8616条查询结果,搜索用时 15 毫秒
1.
Zhao Hanzhong 《Acta Mechanica Solida Sinica》2002,15(2):156-162
A finite difference/boundary integral procedure to determine the acoustic reflected pressure from a fluid-loaded bi-laminated
plate is described. The bi-laminate is composed of a piezoelectric layer and an elastic layer in contact with the fluid, and
is held by an acoustically hard baffle. In the numerical model, the fluid pressure at fluid/solid interface is replaced by
a continuum of point sources weighted by the normal acceleration of the elastic plate, and the governing equation system is
solved in the solid domain. With the normal acceleration found, the reflected pressure in the fluid is determined by an integral
expression involving the Green's function. It is demonstrated that an appropriate applied voltage potential across the piezoelectric
layer has the effect of cancelling either the reflected or scattered pressure of the plate at any chosen field points in the
fluid.
Project supported by the National Natural Science Foundation of China (No. 10172039). 相似文献
2.
《ournal of non Newtonian Fluid Mechanics》2007,141(2-3):85-98
Two solutions are presented for fully-developed pipe and planar flows of multimode viscoelastic models. The fluids have a Newtonian solvent contribution and the polymer modes are described by the Phan-Thien—Tanner (PTT), the FENE-P or the Giesekus equation. The first solution is exact and can handle any number of modes, but is only semi-analytical. The second solution, which is presented only for the PTT model with a linear stress coefficient and the FENE-P model, can also handle any number of modes. It is based on a truncated series expansion and is completely analytical, but provides only an approximated solution. The complexity of the multimode solutions is investigated first with the exact semi-analytical method and it is shown that at high Deborah number flows the high-order stresses can become as important as the stress of the first mode. It is also under these conditions that the approximated analytical solution deviates from the exact semi-analytical solution. A criterion for the accurate use of the approximated solution is presented. Fortran codes are provided to obtain these solutions at the internet address at the end. 相似文献
3.
《Physics letters. A》2006,353(5):427-430
In this Letter we discuss squeezing state of magnon in ferromagnet, which permits a reduction in the quantum fluctuation of the spin component to below the zero-point quantum noise level of coherent magnon states. We investigate the generation of squeezed magnon state through calculating the expectation values of spin component fluctuation. The mean field theory is introduced in dealing with the nonlinear interaction terms of Hamiltonian of magnon system. 相似文献
4.
《Physics letters. A》2006,360(2):380-383
One-dimensional dihalide-bridged polymer Co(thiazole)2Cl2 has been studied with the self-consistent full-potential linearized augmented plane wave method (FP_LAPW) based on the density functional theory (DFT). Spin distributions in ferromagnetic and antiferromagnetic states of it have been obtained by the calculation. The electronic structure and magnetic coupling between tow cobalt (II) ions along chain are discussed. 相似文献
5.
6.
Numerical Simulation on the Production Mechanism of Surface-Wave Plasmas Sustained along a Metal Rod
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ZHU Long-Ji CHEN Zhao-Quan YIN Zhi-Xiang WANG Guo-Dong XIA Guang-Qing HU Ye-Lin ZHENG Xiao-Liang ZHOU Meng-Ran CHEN Ming LIU Ming-Hai 《中国物理快报》2014,(3):103-106
For interpreting the production mechanism of surface-wave plasmas sustained along a metal rod, electromagnetic simulation on the electromagnetic field distributions and particle-in-cell/Monte Carlo collision (PIC/MCC) simulation of the ionization process are present. The results show that the enhanced electric field of surface plasmon polaritons (SPPs) can be excited in the ion sheath layer between the negative-voltage metal rod and the surface-wave plasmas, which is responsible for maintaining the plasma discharge. Moreover, the spatio-temporal evolutions of plasma density and electric fields are simulated by the PIC/MCC model. It is further suggested that the expanded ion sheath layer can extend the length of plasma domain by increasing the plasma absorbed energy from SPPs. 相似文献
7.
《Physics letters. A》2014,378(16-17):1085-1090
The formations of n-order two-soliton bound states (TSBSs) in the Bose–Einstein condensates with spatiotemporally modulated nonlinearities are studied. Exact analytical expressions of the n-order TSBSs are derived by means of the similarity transformations. Further, the numerical simulations are carried out, consistent with the analytical results very well. The stability analysis shows that the solutions can be stable. Our results indicate that the attractive spatiotemporal inhomogeneous nonlinearities can support n-order TSBSs, which has the potential applications to the generation of matter-wave bright solitons in harmonic traps. 相似文献
8.
Li Yuanjie 《International Journal of Theoretical Physics》1993,32(9):1619-1625
In this paper we propose a new theory of a fiber bundle provided with a local metric of internal space. The fibers differ from usual fibers, having an enlarged factor. The enlargement may be procured by a differential mapping(x) from structure groupG to the fiberF
x atx M, and(x)R. The torsion presented stems from the local metric of internal space and the local metric stems from a induced mapping
*(x) of(x). From the theory we can get the Brans-Dicke theory with torsion. If we assume the spin density of the gauge field determines the enlarged factor of the fiberF
x, our theory is an extended Cartan theory. 相似文献
9.
First-principle calculations based on density function theory (DFT) are used to clarify the roles of γ-Fe2O3 in fly ash for removing mercury from coal-fired flue gases. In this study, the structure of key surface of γ-Fe2O3 is modeled and spin-polarized periodic boundary conditions with the partial relaxation of atom positions are employed. Binding energies of Hg on γ-Fe2O3 (0 0 1) perfect and defective surfaces are calculated for different adsorption sites and the potential adsorption sites are predicted. Additionally, electronic structure is examined to better understand the binding mechanism. It is found that mercury is preferably adsorbed on the bridge site of γ-Fe2O3 (0 0 1) perfect surface, with binding energy of −54.3 kJ/mol. The much stronger binding occurs at oxygen vacancy surface with binding energy of −134.6 kJ/mol. The calculations also show that the formation of hybridized orbital between Hg and Fe atom of γ-Fe2O3 (0 0 1) is responsible for the relatively strong interaction of mercury with the solid surface, which suggests that the presently described processes are all noncatalytic in nature. However, this is a reflection more of mercury's amalgamation ability. 相似文献
10.
CHEN Li-Mei CAO Li WU Da-Jin GE Guo-Qin 《理论物理通讯》2005,44(10)
The effect on intensity correlation time T by input signal is studied for gain-noise model of a single-mode laser driven by colored pump noise and colored quantum noise with colored cross-correlation with a bias signal modulation in this paper. By using the linear approximation method, we detect that there exists maximum (i.e., resonance) in the curve of the intensity correlation time T upon bias-current i0 when the noise correlation coefficient λ is positive; and there exists minimum (i.e., suppression) in the T-i0 curve when λ is negative. And when λ is zero, T increases monotonously with increasing i0. Furthermore, the curve of T upon the signal frequency Ω is also studied. Our study shows that no matter what the value ofλ is, there exists minimum (i.e., suppression) in the T-Ω curve. 相似文献