Z箍缩Al等离子体发射谱的非局域平衡模拟

采用FAC (flexible atomic code)程序, 在细致能级层次计算等离子体原子结构参数和等离子体中各种原子物理过程的基础上, 建立了等离子体中各种能级布居的速率方程, 其中考虑了等离子体中各种原子物理过程的影响. 通过求解基于细致能级的速率方程, 计算了Z箍缩产生的Al等离子体辐射的细致能谱结构, 对实验谱进行了辨认和归类, 并对实验测量谱的成分做了简单分析. 关键词： Z箍缩 细致能级 非局域热动平衡 速率方程     

大气压直流氩等离子体射流工作特性研究

介绍了一种新型大气压直流双阳极等离子喷枪,并对其电特性参数和发射光谱进行了测量.通过对氩等离子体射流的电信号进行时域和频域分析,研究了载气流量和弧电流的变化对射流脉动的影响,结果表明氩等离子体电弧的伏安特性呈上升趋势,射流脉动属于接管模式,电源特性中的交流分量引起的电压波动是影响氩等离子体射流脉动的主要因素. 通过光谱法测量了氩等离子体射流在弧室内和弧室出口的发射光谱,利用玻尔兹曼曲线斜率法计算了射流的激发温度,根据Ar I谱线的斯塔克展宽得到了射流的电子密度,并对等离子体射流满足局域热力学平衡(LTE) 关键词： 等离子喷枪 射流脉动 激发温度 局域热力学平衡     

激光诱导Ca等离子体温度的实验研究

 等离子体温度是激光诱导击穿光谱测量中一个重要的因素。采用Nd:YAG脉冲激光器作为光源击穿样品形成等离子体,其发射光谱由中阶梯光栅光谱仪和ICCD进行分光和光电转换。通过实验得出了300~450 nm波段的光谱图,定性分析出了Ca Ⅱ 315.9, 317.9, 393.4, 396.9 nm和Ca Ⅰ 422.7 nm等发射谱线。根据激光诱导击穿光谱定量公式,等离子体温度的变化对谱线强度有影响。先假设实验中等离子体处于局部热平衡状态,选用Ca的4条一价离子谱线,根据Boltzmann斜线法计算出了等离子体温度,并得到了等离子体温度与Ca质量分数的关系。随着Ca质量分数的增加,等离子体温度也相应增加。但当Ca质量分数小于0.50%时等离子体温度增加的幅度较小,而质量分数大于0.50%时等离子体温度的上升幅度相对较大。最后经过验证,实验中等离子体处于局部热平衡状态的假设成立。     

Development of a new atmospheric pressure cold plasma jet generator and application in sterilization

This paper reports that a new plasma generator at atmospheric pressure, which is composed of two homocentric cylindrical all-metal tubes, successfully generates a cold plasma jet. The inside tube electrode is connected to ground, the outside tube electrode is connected to a high-voltage power supply, and a dielectric layer is covered on the outside tube electrode. When the reactor is operated by low-frequency (6 kHz--20 kHz) AC supply in atmospheric pressure and argon is steadily fed as a discharge gas through inside tube electrode, a cold plasma jet is blown out into air and the plasma gas temperature is only 25--30℃. The electric character of the discharge is studied by using digital real-time oscilloscope (TDS 200-Series), and the discharge is capacitive. Preliminary results are presented on the decontamination of E.colis bacteria and Bacillus subtilis bacteria by this plasma jet, and an optical emission analysis of the plasma jet is presented in this paper. The ozone concentration generated by the plasma jet is 1.0×10¹⁶cm^-3 which is acquired by using the ultraviolet absorption spectroscopy.     

Resonance Raman Spectroscopy of Porphin

We report and discuss Raman spectra of porphin. These were obtained by resonance effect, irradiating in the electronic band IV. Unexpected variations of vibrational band intensities and depolarization ratios were recorded on changing the excitation wavelength. Some implications on the symmetry types of the vibrations are discussed. Results are compared with current data from quasi-linear electronic spectra.     

Tokamak plasma equilibrium analysis based on the relaxation method with a specified magnetic axis

In this contribution, we have presented two techniques for the determination of plasma equilibrium position in IR-T1 tokamak: relaxation and optical methods. An analysis method of tokamak plasma equilibrium by a relaxation method with a specified magnetic axis is presented. The degrees of freedom due to designated positions of the magnetic axis are possible by using poloidal field coil currents. Stable steady-state tokamak plasma equilibria are calculated along with the magnetohydrodynamic potential energy. The plasma generates a plasma current which partially or fully cancels the magnetic field from the poloidal field coils. For low-temperature plasmas, the plasma current distribution is centrally peaked; for high-temperature plasmas, the plasma current has a hole. A centrally peaked current distribution in a low-temperature plasma is evolved into a current distribution with a hole by increasing the plasma pressure by Ohmic heating, radio frequency heating, or by neutral beam injection heating. In the second technique, an image-processing technique was used for the output signal of the charge coupled device camera and plasma emission intensity profile and then the plasma position was obtained. Results are compared and discussed.     

激光诱导Ca等离子体温度的实验研究

等离子体温度是激光诱导击穿光谱测量中一个重要的因素。采用Nd:YAG脉冲激光器作为光源击穿样品形成等离子体,其发射光谱由中阶梯光栅光谱仪和ICCD进行分光和光电转换。通过实验得出了300~450 nm波段的光谱图,定性分析出了Ca Ⅱ 315.9, 317.9, 393.4, 396.9 nm和Ca Ⅰ 422.7 nm等发射谱线。根据激光诱导击穿光谱定量公式,等离子体温度的变化对谱线强度有影响。先假设实验中等离子体处于局部热平衡状态,选用Ca的4条一价离子谱线,根据Boltzmann斜线法计算出了等离子体温度,并得到了等离子体温度与Ca质量分数的关系。随着Ca质量分数的增加,等离子体温度也相应增加。但当Ca质量分数小于0.50%时等离子体温度增加的幅度较小,而质量分数大于0.50%时等离子体温度的上升幅度相对较大。最后经过验证,实验中等离子体处于局部热平衡状态的假设成立。     

Aspects of the upstream region in a plasma jet with dielectric barrier discharge configurations

A plasma column with a length of about 65 cm is generated in the upstream region of a plasma jet using dielectric barrier discharge configurations. The effects of experimental parameters such as the amplitude of the applied voltage and the driving frequency are investigated in aspects of the plasma column by the optical method. Results show that both the plasma length and the propagating velocity, as well as the discharge current, increase with the increase in the applied voltage or its frequency. The discharge mechanism is analysed qualitatively based on streamer theory, where photo-ionization is important. Furthermore, optical emission spectroscopy is used to investigate the electric field intensity of the upstream region.     

Aspects of the dielectric upstream region barrier discharge in a plasma jet with configurations

A plasma column with a length of about 65 cm is generated in the upstream region of a plasma jet using dielectric barrier discharge configurations. The effects of experimental parameters such as the amplitude of the applied voltage and the driving frequency are investigated in aspects of the plasma column by the optical method. Results show that both the plasma length and the propagating velocity, as well as the discharge current, increase with the increase in the applied voltage or its frequency. The discharge mechanism is analysed qualitatively based on streamer theory, where photo-ionization is important. Furthermore, optical emission spectroscopy is used to investigate the electric field intensity of the upstream region.     

电感耦合等离子体原子发射光谱法测定硅铝铁合金中多种元素的优化研究

应用电感耦合等离子体原子发射光谱 (ICP AES)法 ,对硅铝铁合金中的Al,Fe ,Ca,Cr,Mn ,Ni,Si和Ti元素进行了测定。研究了ICP AES的操作条件和溶样方法 ,确定了适宜的实验条件 ,如对仪器参数和共存元素对信号的影响进行了研究。将实验条件优化后 ,使用该方法测定硅铝铁合金中多种元素 ,标准钢样测定结果与推荐值相符。对各种元素的检出限分别为Al(0 0 2 9μg·mL- 1 ) ,Fe(0 0 0 4 μg·mL- 1 ) ,Ca(0 0 0 75 μg·mL- 1 ) ,Cr(0 0 0 15 μg·mL- 1 ) ,Mn(0 0 0 0 9μg·mL- 1 ) ,Ni(0 0 0 2 7μg·mL- 1 ) ,Si(0 0 4 5 μg·mL- 1 )和Ti(0 0 0 3μg·mL- 1 )。对所测元素 ,测定结果的相对标准偏差 (n =6 )在 0 3%～ 1 8%之间 ,加入标准溶液的回收率在96 7%～ 10 2 9%范围。测定合金样品中高含量硅的结果与标准化学 (重量 )法的结果也相符。该方法的特点是数据可靠 ,简便可行和易于推广。     

Effect of shear equilibrium flow in Tokamak plasma on resistive wall modes

A code named LARWM with non-ideal magnetohydrodynamic equations in cylindrical model is used to describe the instability in Tokamak plasma surrounded by a conducting wall with finite resistivity. We mainly take three factors related to the shear equilibrium plasma flow into consideration to study the stabilizing effect of the shear flow on the resistive wall modes (RWMs). The three factors are the velocity amplitude of flow, the shear rate of flow on plasma surface, and the inertial energy of equilibrium plasma flow. In addition, a local shear plasma flow is also calculated by the LARWM code. Consequently, it is found that the inertial energy of the shear equilibrium plasma flow has an important role in the stabilization of the RWMs.     

大气压等离子体辅助多晶硅薄膜化学气相沉积参数诊断

本文采用发射光谱法诊断了大气压下Ar气、SiCl₄及H₂气混合气体（Ar/SiCl₄/H₂）射频放电等离子体射流特性.利用Si原子谱线强度计算了电子激发温度并以此估算了Si原子数密度,研究了射频功率及气体流量对电子激发温度和Si原子数密度以及SiCl₄解离率的作用. 关键词： 大气压等离子体射流 发射光谱 电子激发温度 多晶硅薄膜沉积     

大气压等离子体辅助多晶硅薄膜化学气相沉积参数诊断

本文采用发射光谱法诊断了大气压下Ar气、SiCl₄及H₂气混合气体（Ar/SiCl₄/H₂）射频放电等离子体射流特性.利用Si原子谱线强度计算了电子激发温度并以此估算了Si原子数密度,研究了射频功率及气体流量对电子激发温度和Si原子数密度以及SiCl₄解离率的作用.     

A bound for the pressure integral in a plasma equilibrium

An interpolation inequality for the total variation of the gradient of a composite function is derived by applying the coarea formula. A bound for the pressure integral is studied by establishing ana priori estimate for a solution of the Grad-Shafranov equation of plasma equilibrium. A weak formulation of the Grad-Shafranov equation is given to include singular current profiles.     

大气压射流等离子体中O及OH自由基的发射光谱在线诊断

OH自由基及氧原子在大气化学、表面处理及化学污染物分解等方面有着重要的作用。利用发射光谱技术在线测量了大气压射流等离子体中OH自由基紫外波段与O自由基777,844 nm波段的发射光谱。研究了OH自由基与氧原子光谱强度随放电功率及放电体系中所加入的氧浓度的变化。将实验测得的OH自由基光谱图与用Lifbase数据库模拟光谱图进行比较,估算了OH自由基的转动温度。结果表明：OH自由基的转动温度随放电功率的增加而增加,随工作气体流速的增加而减小。     

Corona discharge as a temperature probe of atmospheric air microwave plasma jet

We developed and tested a new method for temperature measurements of near-LTE air plasmas at atmospheric pressure. This method is specifically suitable for plasmas at relatively low gas temperature (800–1700 K) with no appropriate radiation for direct spectroscopic temperature measurements. Corona discharge producing cold non-equilibrium plasma is employed as a source of excitation and is placed into the microwave plasma jet. The gas temperature of the microwave plasma jet is determined as the rotational temperature of N₂? produced in the corona discharge. The corona probe temperature measurement was tested by the use of a thermocouple. We found a fairly good agreement between the two methods after correcting the thermocouple measured temperatures for radiative losses. The corona probe method can be generally applied to determine the temperature of the near-LTE plasmas and contrary to the thermocouple it can be used for higher plasma temperatures and is not affected by radiative losses and problems of interaction with the microwave plasma and electromagnetic fields.     

金等离子体中Au48+—Au52+平衡分布的统计热力学研究

基于全相对论多组态Dirac-Fock理论，采用“多功能相对论原子结构程序(GRASP2)”，考虑量子电动力学(QED)效应和Breit修正，涉及实验谱中Au等离子体M带的几类重要跃迁，计算了Au48+—Au52+离子的能级结构和能级简并度.用统计热力学方法计算 各离子的配分函数，由配分函数计算等离子体内这五种离子的电离与复合平衡常数，根据同 时反应的平衡理论研究电离与复合达到平衡时等离子体内各离子的相对分布. 关键词： 金等离子体 配分函数 平衡常数 离子丰度     

金等离子体中Au48+-Au52+平衡分布的统计热力学研究

基于全相对论多组态Dirac Fock理论 ,采用“多功能相对论原子结构程序 (GRASP2 )” ,考虑量子电动力学 (QED)效应和Breit修正 ,涉及实验谱中Au等离子体M带的几类重要跃迁 ,计算了Au4 8 —Au52 离子的能级结构和能级简并度 .用统计热力学方法计算各离子的配分函数 ,由配分函数计算等离子体内这五种离子的电离与复合平衡常数 ,根据同时反应的平衡理论研究电离与复合达到平衡时等离子体内各离子的相对分布基于全相对论多组态Dirac Fock理论 ,采用“多功能相对论原子结构程序 (GRASP2 )” ,考虑量子电动力学 (QED)效应和Breit修正 ,涉及实验谱中Au等离子体M带的几类重要跃迁 ,计算了Au4 8 —Au52 离子的能级结构和能级简并度 .用统计热力学方法计算各离子的配分函数 ,由配分函数计算等离子体内这五种离子的电离与复合平衡常数 ,根据同时反应的平衡理论研究电离与复合达到平衡时等离子体内各离子的相对分布     

Stability analysis of a model equilibrium for a gravito-electrostatic sheath in a colloidal plasma under external gravity effect

The present contribution tries to find a scientific answer to the question of stability of an equilibrium plasma sheath in a colloidal plasma system under external gravity effect. A model equilibrium of hydrodynamical character has been discussed on the basis of quasi-hydrostatic approximation of levitational condition. It is found that such an equilibrium is highly unstable to a modified-ion acoustic wave with a conditional likelihood of linear driving of the so-called acoustic mode too. Thus, it is reported (within fluid treatment) that a plasma-sheath edge in a colloidal plasma under external gravity effect could be highly sensitive to the acoustic turbulence. Its consequential role on possible physical mechanism of Coulomb phase transition has been conjectured. However, more rigorous calculations as future course of work are required to corroborate our phenomenological suggestions.     

Spectroscopic investigation of the plasma of a high-current diffuse discharge in He/Ar/CF2Cl2(CCl4) mixtures

Survey emission spectra in the region of 190–600 nm and time and service-life characteristics of a transverse nanosecond discharge in He/Ar/CF₂Cl₂(CCl₄) mixtures at a pressure of 10–100 kPa are investigated. In the emission spectra, excited products of the decomposition of freons—C₂(A−X), CN(B−X), Cl ₂ ^* , C^*, Cl^*, and Cl^+*— and the emission of ArF at λ=193 nm are revealed. The emissions of Cl ₂ ^* at λ=258 nm and ArF at λ=193 nm were the most intense. The discharge in the He/Ar/CF₂Cl₂ mixture is a multiwave emission source with λ=258 nm Cl ₂ ^* 193 nm ArF, and probably, 175 nm Arcl. It is of interest for applications in UV-VUV-range pulse photometry. The duration of the emission on Cl ₂ ^* , ArF, ArI, ClI, and ClII transitions in the discharge in the Ar/CF₂Cl₂ mixture (P=10–20 kPa) was 200–300 nsec. With adding He and increasing pressure to 100 kPa the duration of the emission decreased by a factor of 1.5–2. The basic mechanisms of the formation of Cl₂, ArF, and CN(B) molecules in the transverse-discharge plasma are considered. Uzhgorod State University, 46, Pidgirna Str., Uzhgorod, 294000, Ukraine. Translated from Zhurnal. Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 241–246, March–April, 1999.