排序方式: 共有70条查询结果,搜索用时 15 毫秒
1.
2.
LI Rui ZHANG Duan-Ming HUANG Ming-Tao SU Xiang-Ying CHEN Zhi-Yuan ZHU Hong-Ying ZHANG Lin 《理论物理通讯》2007,48(8):343-347
We propose a two-dimensional model of polydisperse granular mixtures with a power-law size distribution in the presence of stochastic driving. A fractal dimension D is introduced as a measurement of the inhomogeneity of the size distribution of particles. We define the global and partial granular temperatures of the multi-component mixture. By direct simulation Monte Carlo, we investigate how the inhomogeneity of the size distribution influences the dynamic properties of the mixture, focusing on the granular temperature, dissipated energy, velocity distribution, spatial clusterization, and collision time. We get the following results: a single granular temperature does not characterize a multi-component mixture and each species attains its own "granular temperature"; The velocity deviation from Gaussian distribution becomes more and more pronounced and the partial density of the assembly is more inhomogeneous with the increasing value of the fractal dimension D; The global granular temperature decreases and average dissipated energy per particle increases as the value of D augments. 相似文献
3.
微束辐照装置是将辐照样品的束斑缩小到微米量级,能够对辐照粒子进行准确定位和精确计数的实验平台,是开展辐照材料学、辐照生物学、辐照生物医学以及微加工的有力工具.中国科学院近代物理研究所(IMP)正在研制中能重离子微柬辐照装置.该装置以兰州重离子加速器(HIRFL)系统提供的中能和低能重离子束流为基础,采用磁聚焦方式形成微米束.束运线上两台铅垂方向的偏转磁铁辅以四极磁铁构成对称消色差系统,将束流导向地下室,再用高梯度的三组合四极透镜强聚焦形成微米束斑,在真空中或大气中辐照样品.它将成为国内首台能够提供从低能(10MeV/u)到中能(100MeV/u)的重离子微束的公共实验平台,用于定位、定量照射靶物质(生物细胞、组织或其它非生物材料等),有助于深入揭示重离子与物质相互作用的本质,也为探索重离子辐照效应的应用提供新的手段. 相似文献
4.
5.
利用光杠杆装置测量了微位移传感器的灵敏度,用微位移传感器测量了铜的线胀系数,结果显示,与传统的光杠杆放大法相比,微位移传感器测量结果更加稳定和可靠. 相似文献
6.
介绍了重离子治癌装置的最新发展状况 ,比较了两类典型的旋转机架的结构及光学特性 ,给出了离子光学的限制条件 .设计了一台桶形机架 ,为兰州重离子冷却储存环应用于医学治疗进行了预研. A simple plane rotating gantry is proposed at the Heavy Ion Research Facility in Lanzhou (HIRFL), where a new project named Cooling Storage Ring is under construction. The gantry is 18 metre long, 5 metre high from upper beam axes to rotation axes. It consists of eight quadruples, two 45° and one large aperture 90° dipole magnets. It is equipped with a two direction magnetic raster scanning system. A beam spot of radii between 2 to 5 mm can be achieved at∶... 相似文献
7.
8.
给出脉冲激光作用块状靶材的烧蚀模型.根据能量平衡原理,导出烧蚀面的位置随时间的变化关系.利用绝热近似、温度连续性条件和能量平衡原理来获得烧蚀面与固液相界面边界条件.结合热传导方程,利用精确解与积分近似法相结合的方案,给出固液两相的温度分布与时间和位置的变化关系,以及固液相界面的位置随时间的变化规律,并与已有的理论和实验结果进行比较.最后以铝靶为例计算模拟了激光烧蚀的全过程计算.
关键词:
脉冲激光
等离子体
固液相界面
烧蚀面 相似文献
9.
10.
本实验同时研究了4 0Ar+209Bi反应中周边碰撞和中心碰撞两者产生的关联裂变碎片,以及其与α粒子的再关联.对裂变碎片质量分布和能量分布随热裂变核初始温度演化的系统分析,发现中心碰撞和周边碰撞所形成的热核存在着不同的裂变行为. Correlated fission fragments from the 40Ar+209Bi reaction and their further correlation with α particles have been studied for peripheral and central collisions simultaneously. The existence of different fission behavior of hot nuclei formed in central and peripheral collisions was found from the systematic analysis of the mass and energy distributions of fission fragments as a function of the initial temperature of hot fissioning nuclei. 相似文献