Electric Microfield Distributions in Dense One‐ and Two‐Component Plasmas

The electric microfield distributions have been calculated using an integral‐equation method for one‐component plasmas proposed by Iglesias [1] and the coupling‐parameter integration technique for two‐component plasmas proposed by Ortner et al. [2]. Electric microfield distributions are studied in the frame of the Kelbg pseudopotential model, taking into account quantum‐mechanical effects (diffraction, quantum symmetry effects) and screening effects. The screened pseudopotential is represented in a numerically approximated form. The results are compared with simulation results obtained by other authors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Contribution to Calculation of Ion Microfield Nonuniformity Effect on the Asymmetry of Lyman‐α Line in Dense Plasma

The high orders of Stark effects on spectral line shapes are examined in the ion‐static and electron‐impact ap‐proximations. At first the distribution functions of the spatial derivative of the ion microfield in He⁺ plasma are calculated for different plasma conditions when the coupling parameter is weak. We present new results about the spatial derivative ion microfield distributions and apply them to show the asymmetry of the Lyman‐α (Ly‐α) line in He⁺ plasma. At the second stage we show that asymmetry is affected by the spatial derivative tensor of the local ion electric field. We have used the Monte‐Carlo simulation (MCS) to compute the distribution functions for all tensor components and use them to solve the evolution equation of emitter whose solution serves to compute and therefore to show the line shape asymmetry. Good agreement of our distribution functions of ion microfield gradients and the line asymmetry with other results are obtained (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Distribution Function of Spatial Derivative of the Ion Electric Microfield Using the Independent Particles Model in Plasmas

In this work the distribution function of spatial derivative of parallel component of quasistatic ion electric microfield in plasma is calculated. Some physical approximations are used in these calculations, where only interactions between charged emitter and perturber ions are taken into account, as first step. This approximation is known as the independent particles model. Some special functions and series are used in these calculations. It is deduced that the distribution function of spatial derivative of the ion microfield may be depend more on the probability of finding the microfield rather than the microfield value itself (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Relations between Black Hole Spin and Angular Velocity of Accreting Particles near the Horizon

Evolution characters of angular velocity _H of a Kerr black hole (BH) and distribution characters of angular velocity _p of accreting particles near the BH horizon are investigated in the case of thin and thick disks, respectively. It is shown that _H evolves in a non-monotonous way in the case of thin-disk-pure-accretion, attaining a maximum at a _* 0.994. This evolution character turns out to depend on the radial gradient of _p near the BH horizon. It is proved that both quantities, ( d_H /dt) _ms and ( _p /r)_{r=r H}, vanish at the same value of a _*: a _*0.994, and an explanation for the non-monotonousness of _H is provided.     

阈上电离过程中光电子角分布的精细结构

应用非微扰散射理论并考虑自发辐射 ,研究了阈上电离过程中光电子的角分布。由于自发辐射的影响 ,电子的角分布具有精细结构 ,成功地解释了Nandor等人的实验观测。     

19F+27Al反应产物的角分布、角分散与耗散机制

完成了114MeV¹⁹F+²⁷Al深部非弹性碰撞产物的角分布测量.分析了反应产物B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,讨论了反应形成的中间双核系统随时间演化过程中角分布所表现出的耗散特点.从实验上提取了反应产物各元素的角分散参数并作了角分散参数的理论拟合,讨论了角分散参数的物理意义以及角分散参数与耗散反应产物的电荷数Z之间的依赖关系.     

Velocity Distribution of the Powder Particles in Laser Cladding

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Velocity Distribution of the Powder Particles in Laser Cladding

The velocity distribution of powder particles in the laser cladding has an important influence on the motion of liquid in the laser molten pool. In this paper, considering the carrier gas leaving the nozzle to be a steady jet, the velocity distribution of the powder particles is obtained, which can be used as input data in the modelling of the laser cladding.     

Matlab在麦克斯韦速率分布律中的应用

用Matlab软件对麦克斯韦速度及速率分布函数进行了编程,绘制了相应的分布曲线,讨论了不同温度和不同分子质量时麦克斯韦速率分布曲线的变化,并用Matlab的符号计算功能计算了分布在三个典型速率区间的分子数占总分子数的百分比,所有变化规律均符合热学理论中的分子运动规律,为教学提供了参考。     

19F+27Al深部非弹性碰撞产物的角分布

完成了19F+27Al深部非弹性碰撞产物的角分布测量.初步分析了反应产B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,展现出深部非弹性反应机制的特点,显示了反应系统随时间的演化过程. Angular distributions of fragments produced in the deep inelastic collision of~(19)F+~(27)Al have been measured for incident energy of 114 MeV at θ_(lab)= 9~(o), 24~(o), 40~(o), 55~(o), 70~(o) and 85~(o). Angular distributions of dissipative products B, C, N, O, F, Ne, Na, Mg and Al are analyzed to provide an evolution process of the intermediate dinuclear system formed in the reaction.     

Three Dimensional Angular Distributions of X‐Rays in a 4 kJ Plasma Focus Device for Different Anode Tips Using TLD‐100 Dosimeters

Time and energy integrated measurements of the 3‐D angular distribution of X‐rays emission within the chamber of a 4 kJ Mather‐type plasma focus is investigated employing four different anode shapes and using nitrogen as the filling gas by the TLD‐100 thermoluminescence dosimeters. The distributions of X‐ray radiation in the energy range of 5 keV to several hundred keV were bimodal for all of the anode tips, peaked approximately at ±15°. The intensity of X‐rays decreased abruptly along the central axis of the device where the quasi cylindrical plasma pinch was formed. High intensity of X‐ray was observed in the case of a tapered ?at‐end anode, whereas less was obtained with the cylindrical hollow‐end anode. The maximum nitrogen X‐rays were for the tapered flat‐end anode at 4.5 mbar and 13 kV. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

基于双向偏振态激光诱导荧光方法的离子速度分布函数测量

为了评估利用发散磁场构型双电层效应的紧凑式螺旋波等离子体推力器的离子加速效果,探索了一种双向偏振态激光诱导荧光测量方法来对螺旋波等离子体源近出口端的离子速度分布函数进行测量。实验中采用Ar作为螺旋波等离子体源工质,中心波长为611.662 nm的激光以轴向方式注入等离子体,以激励一价Ar离子获得波长为461.086 nm的诱导荧光光谱。为了消除磁化等离子体中逆塞曼效应对激光诱导荧光光谱带来的分裂影响,通过四分之一波片将入射激光分别调制为左旋和右旋圆偏振态,并对其诱导光谱进行了分别测量,结果发现不同磁场强度下两次测量结果的偏移值与理论高度吻合,证明了双向偏振态激光诱导荧光测量方法的理论可行性。进一步,采用高斯型滤波器反卷积算法从测量光谱中去除自然展宽和能量饱和效应,再通过对两次相反偏振态测量结果进行平移处理消除逆塞曼效应,从而分离得到实际的多普勒效应。测量了射频能量600 W,不同轴向位置、磁场大小以及气体压力下的螺旋波Ar等离子体激光诱导荧光光谱,结果表明在该实验条件下离子并没有因双电层效应而达到期望值的加速效果,离子速度的形成可能只是一种磁约束作用下的双极电场所导致,并不能产生好的推力性能。     

The Longitudinal Plasma Modes of κ-Deformed Kaniadakis Distributed Plasmas Carrying Orbital Angular Momentum

Based on plasma kinetic theory, the dispersion and Landau damping of Langmuir and ion-acoustic waves carrying finite orbital angular momentum (OAM) were investigated in the κ-deformed Kaniadakis distributed plasma system. The results showed that the peculiarities of the investigated subjects relied on the deformation parameter κ and OAM parameter η. For both Langmuir and ion-acoustic waves, dispersion was enhanced with increased κ, while the Landau damping was suppressed. Conversely, both the dispersion and Landau damping were depressed by OAM. Moreover, the results coincided with the straight propagating plane waves in a Maxwellian plasma system when κ=0 and η→∞. It was expected that the present results would give more insight into the trapping and transportation of plasma particles and energy.     

Angular Distribution Analysis of Nitrogen Ions in a Low Energy Dense Plasma Focus Device

Angular distribution of nitrogen ions from a 4 kJ plasma focus device (PFD), as obtained by two detection methods was studied. The results obtained with two methods including consisting of (i) polycarbonate (PC) detectors (1 mm thick with about 15 cm diameter large etchable area) using electrochemical etching (ECE) at 50 Hz and 48 kV cm^–1 field strenth and (ii) an array of five Faraday cups (FC) are analyzed, compared and discussed in this paper. The results obtained by the two detectors are quite different. A new concept is proposed in this paper for the ring‐shaped angular distribution of ions. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

离散坐标法在计算生物组织内光场空间角分布中的应用

从辐射传输理论出发,研究了准直光照下层状生物组织内漫射光场的角分布.在辐射传输方程的基础上,采用离散坐标法得到了描述层状生物组织内漫射光传输问题的微分方程组形式,并用特征值-特征矢量方法对其进行了求解,给出了通解形式.结合边界条件对两类典型生物组织内漫射光场角分布进行了数值计算-各向同性组织和前向散射组织,给出了组织内不同深度处漫射光场空间角分布曲线.通过对计算结果比较分析,得到了生物组织内漫射光场空间角分布随深度的变化规律,及边界效应和光学参量对组织内漫射光场空间角分布的影响.     

群体粒子场圆偏入射光侧向散射的角分布实验研究(英文)

对圆偏振光入射到群体粒子场时侧向散射光随角度分布的特性进行了实验研究,散射介质为直径0.065μm和1.24μm的粒子与过滤的蒸馏水所构成的不同浓度的悬浮液。实验结果表明,粒子侧向散射光的各种成分在探测平面内相对散射角度始终呈现对称分布的规律,而随着粒子尺寸、浓度、探测深度的变化,散射光强也相应出现变化,但变化不明显。     

多点激光干涉测速系统和电探针技术在飞片速度测量中的应用对比

 多点激光干涉测速系统和电探针技术均可用于测量高速运动物体的运动参数,为了相互验证测试结果,分析测试系统各因素对测量精度的影响,在平面爆轰波驱动飞片的实验中,利用多点激光干涉测速系统和多组电探针,同时测量金属飞片的自由面速度。将多点激光干涉测速系统测得的飞片速度-时间曲线进行积分,得到飞片的位移-时间曲线,并与电探针测得的飞片到达预定位置的时刻进行对比。结果表明：多点激光干涉测速系统各测点测得的飞片自由面速度随时间的变化曲线一致,各测点测得的速度最大相对偏差为1.45%;对两套测试系统的零时及信号传输时间进行修正后得到,当飞片飞行至5、10、15 mm位置时,电探针测得的飞片到达时刻与多点激光干涉测速系统测试结果的最大偏差值分别为0.02、0.02、0.07 μs;两套系统在同一测点的测试差值随飞片飞行距离的增加而增加,其原因可能是,炸药透镜的波形差对飞片运动的影响随着飞片飞行距离的增加而增大。     

Effect of electron–ion coupling on the electric microfield distribution in plasmas

The electronic and ionic effective potential of a fully ionized hydrogen plasma containing an impurity of electric charge (+Z _m e ) are calculated in a two‐component plasma model under semiclassical conditions using classical statistical mechanics with a regularized electron–ion interaction. These effective potentials are coupled in a system of nonlinear integral equations (or coupled differential equations), which is solved numerically with two methods, namely the fixed‐point method and the Runge–Kutta method. The Baranger–Moser electric microfield distributions are calculated and compared with those from molecular dynamics simulation. Agreement between theory and simulation is satisfactory, in general.     

Measurement of Velocity Distribution in Atomic Beam by Diode Laser with Narrow Line width

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