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61.
Wei-Bin Yan Ying-Jie Zhang Zhong-Xiao Man Heng Fan Yun-Jie Xia 《Annalen der Physik》2023,535(11):2300183
Based on the excellent control of single photons realized by atom-photon-chiral couplings,a novel quantum-optics scheme for supervised learning is proposed. The single-photon rotating and phase-shift operations, which can be controlled by another single photon, are realized by proper atom-photon-chiral couplings. Then, an algorithm to perform the supervised learning tasks, composed by integrating the realized gates, and implemented by the tunable gate parameters, is realized. 相似文献
62.
经典Volterra算子$V$及其伴随算子$V^*$在复空间$L^2[0,1]$中起着关键作用. 关于$V$和$V^*$的线性组合的性质, 我们给出了确保$z_1V+z_2V^*(z_1,z_2\in\mathbb{C})$满足增生性质的等价条件. 本文描述了$(u+iv)I+mV+nV^*(u,v,m,n\in\mathbb{R},m+n\geq0)$数值域的精确表示. 相似文献
63.
64.
隐式Newmark法分析波动问题精度的探讨 总被引:2,自引:0,他引:2
本文研究了用平均加速度的Newmark积分格式求解一维平面弹性波动问题的精度。由于平均加速度的Newmark积分格式没有振幅衰减、不产生数值阻尼,因此采用此法分析波动问题会产生较强的高频振荡,尤其是加速度的计算值误差甚大。本文对防护工程中常见的平台型荷载和升压三角形荷载作用下的波动问题,应用有限元分析的实例表明:采用有数值阻尼的Newmark积分格式是改进有限元求解波动问题的一个有效方法,可以大大地提高应力和加速度求解精度。文中推荐的有数值阻尼Newmark积分格式的积分参数(=0.9,=0.49)可供工程中土与结构动力分析时参考使用。 相似文献
65.
Many natural rock systems contain small patches of different permeability which affect the flow of fluids through them. As these heterogeneities become smaller and more numerous, they become harder to model numerically. We consider how to reduce the computational effort required in simulations by incorporating their effects in the boundary conditions at the edges of each grid block. This is in contrast with current methods which involve often arbitrary changes in the fluid properties. The method is restricted to the case of widely-spaced patches, which simplifies interaction effects. The system then reduces to an array of dipoles, and two averaging methods are proposed for finite grid blocks. Several infinite systems, including vertical and horizontal bands, are also considered as further approximations. There is a great wealth of existing results from different fields which lead to identical mathematical problems and which can be used in these cases. Finally, we consider how to use these techniques when the precise configuration of the grid block is not known, but only its statistical properties. This can lead to results which are very different from the deterministic case. 相似文献
66.
The low Reynolds number turbulent flow and mixing in a confined impinging jet reactor 总被引:1,自引:0,他引:1
Florian Schwertfirm Johannes Gradl Hans C. Schwarzer Wolfgang Peukert Michael Manhart 《International Journal of Heat and Fluid Flow》2007,28(6):1429-1442
Turbulent mixing takes an important role in chemical engineering, especially when the chemical reaction is fast compared to the mixing time. In this context a detailed knowledge of the flow field, the distribution of turbulent kinetic energy (TKE) and its dissipation rate is important, as these quantities are used for many mixing models. For this reason we conduct a direct numerical simulation (DNS) of a confined impinging jet reactor (CIJR) at Re = 500 and Sc = 1. The data is compared with particle image velocimetry (PIV) measurements and the basic flow features match between simulation and experiment. The DNS data is analysed and it is shown that the flow is dominated by a stable vortex in the main mixing duct. High intensities of turbulent kinetic energy and dissipation are found in the impingement zone which decrease rapidly towards the exit of the CIJR. In the whole CIJR the turbulence is not in equilibrium. The strong mixing in the impingement zone leads to a rapid development of a monomodal PDF. Due to the special properties of the flow field, a bimodal PDF is generated in cross-sections downstream the impingement zone, that slowly relaxes under relaminarising conditions. The time required for meso-mixing is dominating the overall mixing performance. 相似文献
67.
生物瓣膜应力的数值模拟 总被引:2,自引:0,他引:2
应用有限元方法分析了瓣架的材料特性、瓣叶的材料特性和瓣叶的钙化等因素对瓣叶的应力分布的影响。分析结果表明:采用全弹性材料的瓣架将改善瓣叶的应力分布,最大应力区域将远离接缝部位;将生物瓣瓣叶材料简化为拟线弹性材料时,对瓣叶最大主应力等值线的分布影响不大,计算结果在一定范围内存在差异;当瓣叶出现钙化时,钙化点及其周围产生应力集中,促进钙化的进一步加剧。 相似文献
68.
69.
In this paper, turbulence in a complicated pipe is simulated by using the k-ε model. The ladder-like mesh approximation is used to solve the problem of complicated boundary with the result of numerical simulation favorable. Two computational examples are given to validate the strong adaptability and stability of k-ε model. 相似文献
70.