强流脉冲离子束辐照对DZ4合金微观结构的影响

利用成分为Cn+(30 mol%)和H+(70 mol%),加速电压为250 kV,脉冲宽度为70 ns,束流密度为100 A/cm2的强流脉冲离子束(high intensity pulsed ion beam-HIPIB)辐照DZ4镍基高温合金,辐照次数分别为5、10和15次.利用透射电子显微镜(TEM)分析辐照前后合金表层微观结构的变化.结果显示,与原始样品比较,辐照不同次数后的样品最表面都产生了一层晶粒度为5～10 nm的多晶层,它是由DZ4合金中各元素的单质相组成的.在距表面一定深度范围内,不存在γ'相;随着深度的增加,γ'相的含量逐渐增加.     

HL-l装置初步实验研究

HL-1装置在纵向磁场2.3T下运行,获得了135kA平衡稳定等离子体(平顶时间150ms)。电子温度500eV,电子密度2.5×10~(13)cm~(-3),能量约束时间10ms,有效电荷数小于3,最低稳定运行安全因子2.5。实验表明,纵场杂散分量仅约纵场的万分之一,导体壳和平衡场基本上能保证等离子体的平衡。放电延续时间可长达1.04s。在对MHD稳定性进行大量观测的基础上,确定了稳定运行区域;极限密度符合Murakami定标律。在现有的欧姆加热条件下,能量约束时间服从Alcator C定标律。 本文对实验结果进行了综合分析讨论。     

A Study on the Tuned Bias of Substrate in an Inductively-coupled Plasma Source

1. IntroductionRadio-frequency (rf) capacitively-coupled plasma(CCP) source has been successfully used in manyfields such as film deposition, etching, surfaCe modification. However, one of the disadvantages of thisplasma discharge is the lack of independent control over plasma generation and bombarding energy of ion upon the processed materials surface [1].To achieve independent control over the above twoprocesses) researchers have put forth different techniques. A variable inductor was plac…     

B_3N_3H_6微波等离子体增强化学气相沉积B－N薄膜

采用Ｂ３Ｎ３Ｈ６－Ｎ２混合气体为原料，余辉微波等离子体增强化学气相沉积ＢＮ薄膜．漫反射富氏变换红外光谱分析表明，在５５０℃沉积温度下，ＩＣｒ１８Ｎｉ９Ｔｉ基片上获得了低含氢量的ｃ－ＢＮ和少量ｈ－ＢＮ相的混合薄膜．薄膜Ｋｎｏｏｐ硬度值为２０．８ＧＰａ．划痕试验法测定薄膜的附着性，临界载荷为８．１Ｎ．     

The Effect of the Charge Fluctuation of Dust Parti-cles on Ion-acoustic Wave Excited Through Ionization Instability

The effect of the charge fluctuation of dust particles on ion acoustic wave (IAW) excited through ionization instability was investigated. The hydrodynamic equations and linear time-dependent perturbation theory served as the starting point of theory, by which the dispersion relation and growth rate of the IAW were given. By comparing the results with the case of constant dust charges, it was found that the charge fluctuation of dust particles reduces the instability of the wave mode.     

工程陶瓷的等离子弧加工技术

介绍了附加阳极等离子弧加工陶瓷材料的基本原理、基本形式和特点 ,以切割厚度为 6mm的 Al2 O3陶瓷板为例 ,研究了水再约束、磁场再约束、水磁综合再约束等各种约束条件对等离子弧柱特性及切口质量的影响规律。结果表明 ,喷嘴直径为 4mm时 ,切口宽度小于 5 mm,切口角小于 3°,无渣切速可达 0 .8～ 1 m/min     

ICPECVD类金刚石膜沉积过程的发射光谱诊断研究

利用发射光谱(Optical emission spectroscopy,OES)对感应耦合等离子体增强化学气相沉积(Inductivelycoupled plasma enhance chemical vapor d印osition,ICPECVD)类金刚石(Diamondlike carbon,DLC)膜过程中的各种基团进行分析,并对不同条件下薄膜沉积速率以及薄膜显微硬度进行测试.分析结果发现,感应耦合等离子体源激发甲烷等离子体中存在比较突出的碳氢离子成分,从而促进形成高硬度的DLC膜.而且射频功率、沉积气压等沉积参数的变化对DLC薄膜沉积过程的中性基团、离子基团以及原子氢等成分都有着明显影响,从而最终影响薄膜沉积过程及薄膜性质.     

梯度磁场对芝麻种子生物效应的影响

用电流为0,12.5,37.5,50和62.5A的磁场处理芝麻种子,第二天对处理过的种子用电子顺磁共振(ESR)波谱仪进行测定,发现磁场能促进芝麻种子内部自由基浓度增加。运用ESR波谱仪对磁场处理过的种子连续两周跟踪测量,结果表明自由基浓度随着贮藏时间的延长明显降低。在最佳处理强度的基础上,又设置了0,12,24,36,48,60m in的不同处理时间,结论:以电流50A(场强83.5mT)下处理36~48m in效果最佳。     

强流脉冲离子束模型及辐照靶材能量沉积的模拟研究

强流脉冲离子束(IPIB)及其在靶材中沉积的能量是研究束流与靶材作用的基础.根据三束材料改性国家重点实验室从俄罗斯引进TEMPⅡ型加速器实测的磁绝缘二极管(MID)的加速电压波形及法拉第杯检测到的MID焦点处离子流密度波形,对其进行拟合得到高斯脉冲分布模型,以此为基础采用Monte Carlo方法模拟了离子在铝靶内沉积的能量,得到了一个脉冲内靶材内沉积的能量的时空演化规律.计算了单能离子束以20°～40°角入射铝靶情形.不同能量的单能H+束和C+束以一定角度入射时的最大射程比垂直入射时都要小,表面处单位长度沉积的能量随入射角的增加而增多.IPIB入射铝靶时变化规律同单能离子束.同时对H+和C+二维入射靶材情况也进行了模拟研究.     

Flow Simulation and Optimization of Plasma Reactors for Coal Gasification

This paper reports a 3-d numerical simulation system to analyze the complicated flow in plasma reactors for coal gasification, which involve complex chemical reaction, two-phase flow and plasma effect. On the basis of analytic results, the distribution of the density, tempera-ture and components‘ concentration are obtained and a different plasma reactor configuration is proposed to optimize the flow parameters. The numerical simulation results show an improved conversion ratio of the coal gasification. Different kinds of chemical reaction models are used to simulate the complex flow inside the reactor. It can be concluded that the numerical simulation system can be very useful for the design and optimization of the plasma reactor.