Monoenergetic electron parameters in a spheroid bubble model

A reliable analytical expression for the potential of plasma waves with phase velocities near the speed of light is derived.The presented spheroid cavity model is more consistent than the previous spherical and ellipsoidal models and it explains the mono-energetic electron trajectory more accurately,especially at the relativistic region.The maximum energy of electrons is calculated and it is shown that the maximum energy of the spheroid model is less than that of the spherical model.The electron energy spectrum is also calculated and it is found that the energy distribution ratio of electrons △E/E for the spheroid model under the conditions reported here is half that of the spherical model and it is in good agreement with the experimental value in the same conditions.As a result,the quasi-mono-energetic electron output beam interacting with the laser plasma can be more appropriately described with this model.     

纳米科技——癌症治疗新攻略

纳米科技（NST，即Nanometer Scale Science and Technology）是研究尺寸在0．1nm～100nm范围内的物质运动规律、相互作用和实际应用的一门高新科技．在21世纪前几十年将迅猛发展，纳米技术势必成为推动社会经济各领域快速发展的主导技术之一．随着纳米技术的发展，纳米技术在医疗方面的运用已经越来越广泛．本文将主要阐述纳米科技在癌症治疗中的应用及研究进展情况．     

给定密度随机数的生成的通用方法与球面和球体上均匀随机向量的生成法

本文首先介绍基于垂直概率密度表示的,给定密度函数的随机数生成的通用方法;然后介绍球面及球体上均匀随机向量的生成算法。     

体育运动中的力学原理

 如果你是位体育迷的话,那么对于球类中的“香蕉球”、“勾手飘球”、“上旋球”、“下旋球”等等一定十分熟悉,对于体操或跳水运动中的各种空翻、转体、腾越动作非常欣赏,但这些怪球、好球是如何打出(或踢出)的,这些优美高难度动作是如何设计的?其中可有学问呢!它与力学原理关系密切,下面通过一些具体事例来说明.     

探究正四面体的中心

一正四面体的棱长为a,它的内切球和外接球体积各为多少？问题是数学的灵魂,解决这个问题的关键是找到正四面体的中心所在．只要找到中心,就容易求内切球和外接球的半径,进而求出体积．下面探究四面体的中心位置．     

Liquid bridge force between two unequal-sized spheres or a sphere and a plane

Liquid bridge force acting between wet particles is an important property in particle characterization. This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a flat plate under conditions where gravitational effect arising from bridge distortion is negligible. In order to calculate the force of the liquid bridge efficiently and accurately, expressions of liquid configuration and liquid bridge force were derived by building a mechanical model, which assumes the liquid bridge to be circular in shape between either two unequal-sized spheres or a sphere and a plane. To assess the accuracy of the numerical results of the calculated liquid bridge forces, they were compared to the published experimental data.     

巧测地球的周长

古希腊哲学家亚里士多德在<天论>一书中,明确地提出了地球是一个球体,但当时很多人不相信这个结论埃拉托色尼(公元前275年-公元前194年)是古希腊著名的科学家,他十分崇拜亚里士多德,对毕达哥拉斯、亚里士多德提出的关于地球是一个球体的论述深信不疑,并千方百计地要测出地球的大小.     

简易模板剂法制备多级介孔TiO2微球及其在染料敏化太阳能电池中的性能

采用模板剂法一步合成分级结构的介孔TiO₂微球, 考察了烷基胺类模板剂中烷基链长度对介孔TiO₂微球合成及性能影响. 将其应用于染料敏化太阳能电池的光阳极半导体薄膜中, 得到了9.5%-10.1%的高能量转换效率. X射线衍射(XRD)、物理吸附仪(BET)、扫描电镜(SEM)等的分析结果表明: 分级结构介孔TiO₂微球的晶相为纯锐钛矿型; 介孔TiO₂微球表面粗糙, 的纳米粒子堆积形成, 使微球具有介孔性质和较适宜的比表面积. 介孔TiO₂微球堆积形成了利于物质扩散的通道并具有良好的光散射效果; 同时微球介孔粗糙表面保证了染料的大量吸附, 从而提高了电池的光电流. 通过电化学阻抗分析结果验证了分等级结构介孔TiO₂微球光阳极有利于电解液的传输和物质扩散的优异性能.     

基于气力输送技术大体积类球体物料运动特性研究

为了获取大体积物料物理属性参数、负载综合阻力系数和物料形状系数等关键参数,研究不同气力输送条件下大体积物料的运动规律,课题采用理论计算、仿真分析和测试试验相结合的方法,完成了不同体积、不同密度以及不同输送条件下,大体积类球体物料运动特性参数获取、试验测取数据校正和运动数据的对比分析.数据表明,在设定输送条件下,物料运动...