共查询到16条相似文献,搜索用时 78 毫秒
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转动传能的量子干涉效应在静态池实验中发现,并且已测得积分干涉角.为了得到更多关于穿能的准确信息,应利用分之束进行实验.本文基于一阶含时波恩近似,模拟了利用分子束实验进行量子干涉效应研究的理论模型.此模型采用了Lennard-Jones 相互作用势和直线轨道近似.通过本文建立的模型,研究了影响干涉效应的微分干涉角的因素,并且得到了微分干涉角和碰撞速度、碰撞参数及碰撞伴间的关系.此理论模型对于对于指导分子束实验具有重要的意义. 相似文献
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电子与H3^+离子碰撞中的Balmer α,β,γ发射 总被引:1,自引:1,他引:0
最近,我们利用光学多道分析器对电子与H3^+郭子交叉束碰撞诱发的激发态进行了实验研究,观察到了碰撞中的发射光谱和激发通道,测量了激发截面随能量变化的依赖关系,定性讨论了复合分解激发机制问题。 相似文献
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Abstract Collision cascades in Cu, Au and Cu3Au are generated by full molecular dynamics (MD) and by its binary collision approximation (BCA) with the Marlowe program. Cu and Au primaries have 1 keV initial energy. The same Molière repulsive potential is used in both models for close encounters. In the MD model, this potential is carefully splined to the pair component of the N-body potential developed by Ackland and Vitek. In the BCA, this N-body interaction is roughly modeled by a constant isotropic 4 eV binding energy of the target atoms to their rest positions. Time distributions of the number of atoms moving with a total energy higher than a threshold value E d are compared and discussed. Recoil range distributions during the cascade development are discussed as well. The agreement between MD and BCA is fairly good in all cases for E d larger than about 3 eV. In the case of smaller E d-values, the BCA may result in an overestimate of the number of moving atoms in the late development of the cascades. This discrepancy is suggested to originate in the lack of attractive forces between the moving particles and the surrounding atoms in the BCA. 相似文献
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Three physical mechanisms which may affect dispersion of particle's motion in wall-bounded turbulent flows,
including the effects of turbulence, wall roughness in particle-wall collisions, and inter-particle collisions, are numerically investigated in this study.
Parametric studies with different wall roughness extents and with different mass loading ratios of particles are performed in fully developed channel flows with the Eulerian-Lagrangian approach.
A low-Reynolds-number $k-\epsilon$ turbulence model is applied for the solution of the carrier-flow field,
while the deterministic Lagrangian method together with binary-collision hard-sphere model is applied for the solution of particle motion.
It is shown that the mechanism of inter-particle collisions should be taken into account in the modeling except for the flows laden with sufficiently low mass loading ratios of particles.
Influences of wall roughness on particle dispersion due to particle-wall collisions are found to be considerable in the bounded particle-laden flow.
Since the investigated particles are associated with large Stokes numbers, i.e., larger than $\mathcal{O}(1)$, in the test problem,
the effects of turbulence on particle dispersion are much less considerable, as expected, in comparison with another two physical mechanisms investigated in the study. 相似文献
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DETERMINATION OF THE LIFETIME OF THE 4p1P0 STATE OF CALCIUM BY ELECTRON PHOTON COINCIDENCE 下载免费PDF全文
M.A.K.Elfayoumi 《中国物理》2001,10(11):1017-1020
The electron-photon delayed coincidence technique has been used to measure precisely the lifetime for the 4p1P0 state in calcium. The lifetime of this state was obtained by measuring the time correlation spectrum between the inelastically scattered electrons and the corresponding de-excitation photons. By using the least-squares fitting program to fit Gale's equation to the data points, a value of (4.15±0.17) ns was obtained. The result was compared to some of the earlier experimental measurements. 相似文献