氢闸流管放电猝熄实验现象

 氢闸流管脉内放电猝熄给高功率氢闸流管的放电脉冲宽度和峰值电流或峰值功率能力设置了一定限制,造成工作不稳定。还观察到另一种不同的脉间猝熄现象。随着运行时间增加,由于氢吸除损失,点火延迟及跳动均逐渐增加,板耗明显上升。在正失配下,脉冲形成网络上的剩余正电压将增加,且往往不稳定。当氢压减小超过一定限度,脉冲漏失现象出现,这种脉间猝熄很不稳定。     

低温等离子体物理进展

概述了低温等离子体物理研究现状、发展及其应用      

宏观速度对电弧螺旋不稳定性影响的数值分析

采用抛物型电导率和与时间有关的线性微扰理论,给出了有宏观速度存在的热势分布(温度分布)、稳定性条件以及不稳定性增长率等定量结果。     

开断器中的电弧现象研究

开关、断路器中的电弧研究与等离子体化学是低温等离子体两个通常的应用领域。开断器中电弧物理过程的研究结果可应用于回路开断、限止过失电流及脉冲功率系统中。脉冲功率技术可应用于原子能聚变发电及其模拟。随着电力系统的容量不断增加,对开断过程的技      

Numerical Study of a Free-Burning Argon Arc with Copper Contamination from the Anode

The present modeling of a free-burning argon arc accounts for copper vapor contamination from the anode. Simulations are made for an atmospheric arc that has a length of 10 mm and an electric current of 200 amps. Predicted results for two different anode evaporation rates are compared to those from a pure argon arc with no copper vapor contamination. Copper vapor concentration, temperature, electric potential, and current density profiles are presented. Included in this analysis are radiation losses from both the argon and copper by using recently calculated net emission coefficients. It was found that evaporation of copper from the anode results in a cooling of the arc in a region close to the anode, but has an insignificant influence on the arc close to the cathode. Due to the arc flow characteristics most of the copper vapor tends to be confined to the anode region.     

Arc root dynamics in high power plasma torches — Evidence of chaotic behavior

Although plasma torches have been commercially available for about 50 years, areas such as plasma gun design, process efficiency, reproducibility, plasma stability, torch lives etc. have remained mostly unattended. Recent torch developments have been focusing on the basic understanding of the plasma column and its dynamics inside the plasma torch, the interaction of plasma jet and the powders, the interaction of the plasma jet with surroundings and the impingement of the jet on the substrate. Two of the major causes of erratic and poor performance of a variety of thermal plasma processes are currently identified as the fluctuations arising out of the arc root movement on the electrodes inside the plasma torch and the fluid dynamic instabilities arising out of entrainment of the air into the plasma jet. This paper reviews the current state of understanding of these fluctuations as well as the dynamics of arc root movement in plasma torches. The work done at the author’s laboratory on studying the fluctuations in arc voltage, arc current, acoustic emissions and optical emissions are also presented. These fluctuations are observed to be chaotic and interrelated. Real time monitoring and controlling the arc instabilities through chaos characterization parameters can greatly contribute to the understanding of electrode erosion as well as improvement of plasma torch lifetime.     

波纹板结构动力学建模及其自由振动特性分析

波纹板结构是高速列车中较为常见的型材结构,因其具有轻质、高强度和高稳定性等一系列优点,所以广泛应用于车体结构轻量化设计。首先,基于一阶剪切变形理论和中厚壳(圆弧壳)理论,采用微分求积有限元法(DQFEM)建立一般边界条件下五自由度波纹板结构的通用动力学分析模型;紧接着对五自由度波纹板结构动力学模型进行收敛性验证,确定最佳微分节点数和惩罚因子的取值;然后,采用有限软件(ABAQUS)验证了建立模型的准确性;最后根据已建立模型,研究波纹板结构参数对其振动特性的影响。结果表明,波纹板结构厚度和固支边界条件会增加其固有频率,提高波纹板结构的稳定性,使得共振频率向高频移动;增加波纹板结构长度、参与耦合圆弧壳半径和参与耦合圆弧壳弧度会降低其固有频率,使得共振频率向低频移动。     

圆的线性化裁剪及填充算法

基于多步法绘制理论和Brensenham算法,提出了一种新的关于圆的裁剪及填充算法．此法的主要思想是：根据给定的圆半径,首先线性化生成一个1／8圆弧的多步数目的数组Ar[NR1],然后考虑到各种裁剪需要,可计算出相应圆的裁剪数据,最后再绘出或填充所求的裁剪图形．     

电弧直读光谱仪的开发与应用

介绍一种国内首创的电弧直读光谱仪。该仪器由交/直流电弧激发光源、凹面光栅分光系统、光电倍增管接收器及智能测控系统所组成。研制成功地质样品专用的"交流电弧直读光谱仪"和高纯金属专用的"直流电弧直读光谱仪"可取代1m或2m光栅摄谱仪,省去了光谱相板、洗相及译谱等繁琐的操作程序。在优化的分析条件下,可直接对粉末状地球化学样品及高纯金属氧化物中的多种微量元素同时进行直读光谱测定,具有灵敏、准确、快速的特点,各项技术指标符合所属领域的"国家标准"及"行业规范"的要求。现已有多家使用单位采用"交流电弧直读光谱仪"分析了十几万件地球化学样品中的银、锡和硼等元素,取得了良好的应用效果。