Study of Current Sheath Velocity and Its Distribution Using Tridimensional Magnetic Probe in Sahand Plasma Focus

The current sheath velocity in 0.25 Torr gas pressure of Filippov type plasma focus is studied experimentally.By using two tridimensional magnetic probes on top of the anode surface,the current sheath velocity is measured for argon,oxygen and nitrogen.Additionally,the effect of charging voltage on the current sheath velocity is studied in both axial and radial phases.We found that,the maximum current sheath velocities at both radial and axial phases are respectively 4.33 ± 0.28(cm/μs) and 3.92 ± 0.75(cm/μs) with argon as the working gas at 17 kV.Also,the minimum values of current sheath velocity are 1.48 ± 0.15(cm/μs) at the radial phase and 1.14 ± 0.09(cm/μs) at the axial phase with oxygen at 12 kV.The current sheath velocity at the radial phase is higher than that at the axial phase for all gases and voltages.In this study,variation of the full width half maximum(FWHM) of magnetic probe signals with voltage is investigated for different gases at radial and axial phases.     

Experiments and modeling of discharge characteristics in water-mist sprays generated by pressure-swirl atomizers

Pressure-swirl atomizers are often employed to generate a water-mist spray,typically employed in fire suppression.In the present study,an experimental characterization of dispersion(velocity and cone angle)and atomization(drop-size axial evolution)was carried out following a previously developed methodology,with specific reference to the initial region of the spray.Laser-based techniques were used to quantitatively evaluate the considered phenomena:velocity field was reconstructed through a Particle Image Velocimetry analysis;drop-size distribution was measured by a Malvern Spraytec device,highlighting secondary atomization and subsequent coalescence along the spray axis.Moreover,a comprehensive set of relations was validated as predictive of the involved parameters,following an inviscid-fluid approach.The proposed model pertains to early studies on pressure-swirl atomizers and primarily yields to determine both initial velocity and cone angle.The spray thickness is also predicted and a classic correlation for Sauter Mean Diameter is shown to provide good agreement with experimental results.The analysis was carried out at the operative pressure of 80 bar;two injectors were employed featuring different orifice diameters and flow numbers,as a sort of parametric approach to this spray typology.     

大数据

大数据（Big Data）,或称巨量资料,指的是所涉及的资料量规模巨大到无法通过目前主流软件工具,在合理时间内达到撷取、管理、处理并整理成为帮助企业经营决策更积极目的的资讯。大数据具有4V特点：Volume（大量）、Velocity（高速）、Variety（多样）、Veracity（真实）。     

赫-巴流体在同心环空中速度分布规律的研究

将赫谢尔-巴尔克莱的本构方程与运动方程相结合，推导出了赫-巴流体在环空中作层流运动时的速度分布规律。研究证明，赫-巴流体在动切力下存在塞流，塞流的宽度与赫-巴动切力成正比，压力梯度成反比。最后通过数值分析，讨论了压力梯度、流变指数、动切力对速度分布的影响。随着流变指数的增大，等速核的宽度逐渐增大，速度减小。     

3dfx Voodoo3 2000的“赛扬”版本Velocity 100

虽然更强劲的3D卡是玩家的高级魔鬼机器进一步武装的利齿。但是毕竟最大部分的市场属于那些普通的用户或者普通玩家,他们并不需要在那3D游戏中十几或二十几fps的提升,而且也并没有为此投入更多预算。曾经有朋友问我500块钱左右可以买什么样的显示卡?我曾试过市面大部分显示卡,其中一部分虽然性能不错,但是看着朋友要为此被“抢略”也于心不忍。另一部分价钱虽然合适,但是一分钱一分货,我也不想以后这些产品变成他升级时的鸡肋。想要跟他说Voodoo3 2000吧,对许多人来说价钱合适性能很好,但是又要加大预算……如果3dfx早些时候宣布这块产品那就好了,现在要购买物美价廉的产品。我肯定会向你推荐3dfx Velocity100。     

双向匀速摆动光学平台的运动规划与虚拟仿真

根据设计要求先对输出摇杆进行了运动规划以得到理想的角速度曲线,利用运动学反求法得到输入曲柄的运动规律;再在ADAMS中对该机构进行了虚拟样机仿真,驱动曲柄按照得到的伺服输入运动规律转动,得到了摇杆的实际输出角速度曲线;经误差分析,结果表明,所设计的曲柄摇杆机构满足光学平台的双向匀速摆动输出要求.     

分布式移动通信系统中基于多普勒测速与卡尔曼滤波的动态定位算法

该文提出了一种分布式移动通信系统中的动态定位算法,算法中首先通过远端天线单元(RAU)测量移动台(MS)的多普勒频偏,将其变换为MS到各RAU方向的径向速度,建立状态方程和观测方程,然后采用扩展卡尔曼滤波法估计移动台的当前位置,并通过逐次迭代即可实现MS运动轨迹的动态估计.因为卡尔曼滤波法的引入,该算法有效地降低了当前估计误差对后续时刻估计值的影响,从而可获得较高的定位精度.     

JetBrains发布IntelliJ IDEA8——以工作效率为中心的最新版创新型Java IDE支持SQL、UML等类图、JBoss Seam、Free Marker和Velocity，提升Java编码体验

布拉格2008年11月7日电／新华美通／一为软件开发商提供工作效率增强型智能工具的创建商Jet Brains（R）己宣布全面推出其以开发商为中心的先进Java IDE新版本-Intelli J （R）IDEA8。     

新品

Siemens PLM Software推出完整的Velocity Series产品组合的新版本．Velocity Series是专门针对中端PLM市场而推出的综合的、预配置的软件组合，包含数字化产品设计、分析、制造和数据管理软件。     

代码生成在电子商务开发平台中的应用

基于模板的代码生成方法克服了基于XML／XSLT方法的性能、模型分割等不足之处，适用于MDA代码生成框架。这种方法使用在基于MDA的电子商务开发平台开发过程中，提高了开发和维护的效率，并且在具体的电子商务网站开发项目中取得了成功。