The residual zonal flow in tokamak plasmas with a poloidal electric field

In a tokamak plasma with auxiliary heating by cyclotron waves, a poloidal electric field will be produced, and as a consequence influence the residual zonal flow(RZF) level. The poloidal electric field can also be induced through biasing electrodes at the edge region of tokamaks.Numerical evaluation for a large aspect ratio circular cross section tokamak for the electron cyclotron wave heating indicates that the RZF level decreases significantly when the poloidal electric field increases. Qualitatively, the ion cyclotron wave heating is able to increase the RZF level. It is difficult to apply the calculation to the real cyclotron wave heating experiments since we need to know factors such as the plasma profiles, the exact power deposition and the cross section geometry, etc. It is possible to use the cyclotron wave heating to control the zonal flow and then to control the turbulence level in tokamak experiments.     

一种用于图象处理的二维开关电容滤波器新的设计系统

本文描述二维实时滤波器开关电容网络的新的设计方法。该设计是在综合法的基础上,利用无损、非倒数原形电路而得到的开关电容网络。本文所使用的几个计算机软件,均已写好并调试,可将其集成为一个完整的设计系统。本文作为该设计系统的实际应用,举例设计一个二维高性能滤波器,该滤波器可以像一个CMOS单片那样实现。若与数字滤波器实现相比较,可达到降低成本和减少功耗的目的。     

Geodesic acoustic modes in tokamak plasmas with anisotropic distribution and a radial equilibrium electric field

The dispersion relation of standard geodesic acoustic modes in tokamak plasmas with anisotropic distribution and a radial equilibrium electric field is derived and analyzed. Both frequencies and damping rates increase with respect to the poloidal Mach number which indicates the strength of the radial electric field. The strength of anisotropy is denoted by the ratio of the parallel temperature(T_‖) to the perpendicular temperature(T_⊥). It is shown that, when the parallel temperature is lower than the perpendicular temperature, the enhanced anisotropy tends to enlarge the real frequency but reduces the damping rate, and when the parallel temperature is higher than the perpendicular temperature, the effect is opposite. The radial equilibrium electric field has stronger effect on the frequency and damping rate for the case with higher parallel temperature than the case with higher perpendicular temperature.     

基于树结构的Web信息抽取

信息提取就是从大量的数据中检索出有用的信息,但一般的Web信息提取技术都是基于对Web上HTML文档的分析.文中提出了一种先将HTML转化为XML形式,再提取信息的方法.XML是用于描述在Intemet网上用于数据交换的数据文档的格式的一种语言标准,它将结构、内容和表现分离.数据可被XML唯一标识,从而有利于用户对数据的组织和检索.这种方法能够达到较高的正确率,同时随着文档的增大,方法也能够保证线性的时间复杂度.     

The Current Profile of Tokamaks in Minimum Dissipation States

The principle of minimum dissipation rate is applied to tokamak plasmas with energy and helicity balances imposed as two constraints.The analytical solution on toroidal current distrbution are derived from the resulting Euler-Lagrangian equation.Three typical forms of current distribution are derived from the resulting Euler-Lagrangian equation.Three typical forms of current profiles are found for low-aspect-ratio tokamake like NSTX.One of them decreases with r on equatorial plane,the second peaks in the inner half part on equatorial plane and the third may have a hole or reverse in the central part.     

Zonal Flows Driven by Small-Scale Drift-Alfven Modes

Generation of zonal flows by small-scale drift-Alfven modes is investigated by adopting the approach of parametric instability with the electron polarization dr...     

质子剂量的解析计算

计算了质子束垂直入射于水中的剂量分布,首先给出宽束入射时的剂量深度曲线。然后以－高斯函数描述多重散射作用,得到了三维剂量分布的积分公式。最后给出了入射粒子束为均匀圆柱时剂量分布离轴比的级数表达式。结果表明,给出的部分计算结果与ＰＴＲＡＮ的结果和实验结果符合较好。     

夏末秋初金沙区域大气颗粒物浓度的变化特征

对2013年8-10月金沙区域大气本底站的大气颗粒物观测资料平均日变化和同期的气象资料的平均日变化进行了分析,并与过去的5年同期数据进行对比分析。结果表明：金沙区域夏末秋初大气颗粒物质量浓度有明显的日变化,受气象要素的日变化影响,大气颗粒物质量浓度与相对湿度呈正相关,且颗粒物越小,相关性越强,风向风速对颗粒物质量浓度影响明显,来自观测点北部和东部的气流使大气颗粒物质量浓度升高,而来自西部和南部的风使大气颗粒物浓度降低。受局地排放和气象条件的共同影响,颗粒物质量浓度在凌晨、夜间显著上升。     

加强乡镇企业计量管理队伍的建设

有人认为企业计量工作的好坏,决定于企业领导的重视程度,这的确不假。但企业计量工作的目标和定位合理与否,计量管理人员的主观能动性和工作业绩等正是促使领导重视的关键所在。分散在企业各部门的计量工作需要计量管理人员去统一协调,在整个企业的生产、经营等管理活动中的各种计量工作要靠他们不断深入调查和着意创新。目前很多乡镇企业计量管理人员普遍业务素质较低,部分企业甚至没有专职计量管理人员,有的虽有兼职人员,但兼而不行其职。有的企业原有人员因种种原因,或跳槽或改行,队伍松散,甚至解体。因此,企业计量工作出现滑…     

某市供水管网水质问题及对策

对湛江市供水管网的水质进行了调查研究,发现管网水的浊度、色度、铁和CODMn都比出厂水的略有增加,原水为地下水的管网水浊度及铁合格率比出厂水有较大的下降。从出厂水稳定性、管材和管网水停留时间等方面,对影响管网水质的原因进行了分析,提出了相应的对策。