Bohm Criterion in a Magnetized Plasma Sheath

Bohm criterion in a magnetized plasma sheath is investigated with a fluid model. The upper and lower limits for the sheath criterion in different states of appl...     

The structure of an electronegative magnetized plasma sheath with non-extensive electron distribution

In this paper, an electronegative magnetized plasma sheath model with non-extensive electron distribution is established, and the Bohm criterion affected by the non-extensive parameter q is theoretically derived. The ion Mach number varies with q. The numerical simulation results show that compared with electronegative magnetized plasma sheath with Maxwell distribution (q = 1), the sheath structures with super-extensive distribution (q < 1) and sub-extensive distribution (q > 1) are different. The physical quantities including the sheath potential distribution, ion density distribution, the electron density distribution, negative ion density distribution and the net space charge density distribution are discussed. It is shown that the non-extensive parameter q has a significant influence on the structure of the electronegative magnetized plasma sheath. Due to the Lorentz force, both the magnitude and the angle of the magnetic field affect the structure of the sheath, whether the electrons are Maxwell distributed or non-extensively distributed.     

对市政工程建设中建设项目公司财务治理的几点思考

随着我国市场经济体制的逐步完善、国家投融资体制改革的不断深入和政府职能的转变,市政基础设施的投资渠道已开始呈现多元化的趋势。除一些重点建设项目仍由国家投资建设外,更多的项目已由不同行业、不同性质的企业实体参与投资建设,产生了一批多元化的社会投资群体一一工程业主单位。由此,建设项目公司也就运应而生了。     

基于网格技术的现代远程教学系统模型研究

论文分析了网格的技术结构及其分层的特点,然后指出了其在远程教育系统中对教学资源的强大整合功能。以一个基本的例子说明了其开发的过程,指出网格是未来教育资源整合乃至多行业应用到必然趋势。     

艾默生的新重点

第十二届的“艾默生杯”设计应用大赛的颁奖活动似乎比任何一届都热闹,除去颁奖典礼,11月6日,艾默生环境优化技术还组织了研讨交流会,分别针对冷链物流、传统空调及热泵供暖3个领域的技术走向和热点话题进行讨论,反响颇为热烈。这样的研讨会很明显地反馈了艾默生在市场上的产品走向,除去艾默生环境优化技术一直坚守的空调领域外,其已经把阵地扩大到冷链物流及热泵供暖领域。在研讨会同期,艾默生环境优化技术还特别发布了名为《加强食品安全并降低成本》的冷链研究报告,彰显了艾默生在冷链领域的探索。     

Configuration of 2D Finite Clusters in Plasma Sheath

Finite clusters with a small number of charged particles immersed in a plasma environment have been numerically simulated with a dynamic method. Finite Coulomb clusters are systems of a small number of charged particles, N = 1 to 100, confined by a potential produced by plasma 2D-sheath. Under the action of net force each particle is in an equilibrium position and together they form finite Coulomb clusters. The results of our study show the configuration of Coulomb clusters do not depend on their initial state. After theoretically studied and tested by using the Monte Carlo technique we also prove the system energy is the determinant parameter of the configuration. In addition, the effect of the external magnetic field on the cluster configuration is analyzed.     

Sheath Criterion for an Electronegative Plasma Sheath in an Oblique Magnetic Field

The sheath criterion for an electronegative plasma composed of hot electrons,hot negative ions and cold positive ions in an oblique magnetic field is investigated.We discuss the effects of negative ions and external magnetic field on the sheath criterion.We find that the ion Mach number is of relatively low value because of Coulomb attraction between positive and negative ions.Also the ion Mach number depends on the magnitude and the angle of the magnetic field as well as the initial velocity of ion flow.     

计算机技术在通信领域的运用初探

计算机技术在通信领域的运用主要包括计费系统、信息管理系统、自动查号和数据管理。随着技术的发展和进步,计算机技术将来通信领域得到更为广泛的运用,其作用和地位将会更加凸显。今后为了促进计算机技术在通信领域得到更好的运用,需要采取相应的策略,注重技术创新,完善相关的法律法规和政策,并注重计算机和通信人才的培养。     

虚拟化技术在高性能计算机系统中的应用

介绍了虚拟化技术在整合异构资源、资源管理、系统容错、虚拟化系统环境、并行编程环境等系统的应用。指出应用中存在的不足,并提出相应的完善对策。希望能够为虚拟化技术在高性能计算机系统中得到更好应用提供指导与借鉴。