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941.
Optimized Degenerate Bose-Fermi Mixture in Microgravity: DSMC Simulation of Sympathetic Cooling
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Applying the direct simulation Monte Carlo (DSMC) method developed for the cold atom system, we explore the possibility of a high-efflciency sympathetic cooling process between 87Rb and 40K without gravitational force in an optical trap. The relation between the pre-cooling of Bosons and the sympathetic cooling efficiency is also studied. We find that the absence of gravitational force is beneficial to the process of sympathetic cooling. fhrthermore, an inefficient pre-cooling process will in fact hamper the creation of Fermi degenerate gases. This suggests the advantages of sympathetic cooling in microgravity. 相似文献
942.
943.
Previous research working on local prediction state with some unsuitable neighbor points (such as false points and pseudo-false neighbor points) are the main source of errors of local prediction and these unsuitable neighbors cannot be eliminated entirely. Therefore, an improved local weighted linear prediction model based on local integrated correlation, which can reduce the influence of the residual unsuitable neighbors, is proposed to predict chaotic time series in our study. Simulation results show that the performance of the improved model is superior to the other local prediction models in the prediction of chaotic time series without and with additive white Gaussian noise. 相似文献
944.
946.
A SEMI-ANALYTICAL AND SEMI-NUMERICAL METHOD FOR SOLVING 2-D SOUND-STRUCTURE INTERACTION PROBLEMS 总被引:12,自引:0,他引:12
XiangYu HuangYuying 《Acta Mechanica Solida Sinica》2003,16(2):116-126
Based on the transfer matrix method and the virtual source simulation technique,this paper proposes a novel semi-analytical and semi-numerical method for solving 2-D sound-structure interaction problems under a harmonic excitation. Within any integration segment,as long as its length is small enough, along the circumferential curvilinear coordinate, the nonhomogeneous matrix differential equation of an elastic ring of complex geometrical shape can be rewritten in terms of the homogeneous one by the method of extended homogeneous capacity proposed in this paper. For the exterior fluid domain, the multi-circular virtual source simulation technique is adopted. The source density distributed on each virtual circular curve may be ex-panded as the Fourier‘‘s series. Combining with the inverse fast Fourier transformation, a higher accuracy and efficiency method for solving 2-D exterior Helmholtz‘s problems is presented in this paper. In the aspect of solution to the coupling equations, the state vectors of elastic ring induced by the given harmonic excitation and generalized forces of coefficients of the Fourier series can be obtained respectively by using a high precision integration scheme combined with the method of extended homogeneous capacity put forward in this paper. According to the superposition principle and compatibility conditions at the interface between the elastic ring and fluid, the algebraic equation of system can be directly constructed by using the least square approximation. Examples of acoustic radiation from two typical fluid-loaded elastic rings under a harmonic concentrated force are presented. Numerical results show that the method proposed is more efficient than the mixed FE-BE method in common use. 相似文献
947.
惯性/重力匹配组合导航系统与可视化仿真 总被引:1,自引:0,他引:1
根据惯性/重力匹配组合导航系统的工作原理和特点,提出了基于 RANSA 思想的重力图匹配方法,采用此方法实现了重力图的鲁棒匹配。通过建立组合导航系统的数学模型,采用最优滤波技术实现了组合导航系统的信息融合。在此基础上,采用多种高级语言混合编程,设计实现了一套可视化的仿真软件,对该系统进行了可视化仿真研究。仿真实验结果表明,惯性/重力匹配组合系统相对于无辅助的惯性导航系统,其定位精度、速度精度均有较大的提高,也就是说采用重力匹配方法达到了校正惯导系统,实现高精度导航的目的。 相似文献
948.
基于前人模拟注射填充的显式算法,提出了一种新的全矢量化运算显式算法。对于各类注射填充的模拟,此算法避免了压力场的全局求解,矩阵操作仅在单元一级进行,通过反馈修正,在各时间增量步使已填充的区域满足不可压缩条件。由于避免了所有的全局耦合求解,计算代价与节点的自由度近似成正比,可实现填充模拟过程的高效运算。由于矢量化算法是完全脱耦的,容易实现并行计算。基于这种新算法,应用有限元法进行了注射填充仿真软件的初步开发。其填充模拟结果与商业软件MOLDFLOW的三维模拟结果比较,证实了该软件的有效性。 相似文献
949.
In this paper, a two dimensional Voronoi cell element, formulated with creep, thermal and plastic strain, is applied for the numerical simulation of thermo-mechanical fatigue behavior for particulate reinforced composites. The relation between mechanical fatigue phases and thermal fatigue phases influences the thermo-mechanical fatigue behavior and cyclic creep damage. The topological features of micro-structure in particulate reinforced composites, such as the orientation, depth-width ratio, distribution and volume fraction of inclusions, have a great influence on thermo-mechanical behavior. Some related conclusions are obtained by examples of numerical simulation.The project supported by the Special Funds for the National Major Fundamental Research Projects (2004CB619304), the National Natural Science Foundation of China (10276020 and 50371042), the Key Grant Project of Chinese Ministry of Education (0306) 相似文献
950.
转动刚体上固结悬臂梁系统的动力学数值分析 总被引:4,自引:0,他引:4
本文首先用Jordain变分原理建立了转动刚体上固结悬臂梁系统的动力学方程,然后用数值方法分析了转动梁的变形频率,对系统的自由振动、受迫运动及共振现象等仿真结果作出了解释。 相似文献