排序方式: 共有23条查询结果,搜索用时 15 毫秒
1.
2.
The transient and stationary characteristics of a one-dimensional quantum hydrodynamic model are comparatively studied for semiconductor charge transport in a resonant tunnelling diode. When the bias is not small, our numerical results show a deviation of the asymptotic transient solutions from the stationary ones. A dynamic instability accounts for such deviation. The stationary quantum hydrodynamic model is therefore unsuitable in general for simulating quantum devices. 相似文献
3.
松弛模型中的液气共存平衡态 总被引:1,自引:1,他引:0
对密闭的一维有限长管道里的等温相变.研究了松弛模型中液气共存平衡态的稳定性.使用匹配渐近展开形式上推出了一阶扰动满足的线性系统.理论分析发现.初始小扰动通常会被耗散掉,然而在一些特殊情况下,它们会维持在一定的水平上.数值计算也表明了松弛机制对相变演化具有稳定作用. 相似文献
4.
Elementary waves in Suliciu model for dynamic phase transitions are obtained through traveling wave analysis.For any given initial data with two pieces of constant states,the Riemann solutions are constructed as a combination of elementary waves. When the initial profile contains three pieces of constant states,the solution may be constructed from the Riemann solutions,with each two adjacent states connected by elementary waves.A new Riemann problem forms when these two waves collide.Through the exploration of these Riemann problems,the outcome of wave interactions may be classified in a suitable parametric space. 相似文献
5.
We propose an efficient and robust way to design absorbing boundary conditions in atomistic computations. An optimal discrete boundary condition is obtained by minimizing a functional of a reflection coefficient integral over a range of wave numbers. The minimization is performed with respect to a set of wave numbers, at which transparent absorption is reached. Compared with the optimization with respect to the boundary condition coefficients suggested by E and Huang [Phys. Rev. Lett. 87 (2001) 133501], we reduce considerably the number of independent variables and the computing cost. We further demonstrate with numerical examples that both the optimization and the wave absorption are more robust in the proposed design. 相似文献
6.
Pseudo-Hydrodynamic Approximation for Transient Computation of Energy-Transport Models in Semiconductors 下载免费PDF全文
We propose a pseudo-hydrodynamic (PHD) model that has hyperbolic principal part. It formally converges to the corresponding energy-transport model in the limit of zero momentum relaxation time. Numerical examples have demonstrated the regularization effects of the PHD model. 相似文献
7.
用松弛模型研究了范德瓦流体中的激波管问题.当松弛参数趋于0时模型存在一个确定的黎曼解.在数值方面推导了松弛格式(relaxing)和完全松弛格式(relaxed).在一维问题中,对于不同的剖面,数值模拟显示结果趋向于黎曼解,在理论上和数值上研究了参数的影响.对于特定的初始激波剖面,观察到了非经典的反射波.在二维问题中,研究了曲面波前的数值演化,得到一些有趣的波斑图. 相似文献
8.
对无限介质中波传播进行有界区域近似计算时,需要提出人工边界条件.本文分别就连续介质和离散晶格简要介绍一些典型的人工边界条件,包括精确人工边界条件和局部人工边界条件. 相似文献
9.
10.