A Study of the Gas Flow in the RF Low-Pressure Supersonic Jet Plasma Chemical System

We present results of the experimental study of the gas flow in the RF low-pressure supersonic-jet plasma-chemical reactor. The flow is investigated by using photography with subsequent digital picture processing. The results of the investigations yield valuable data for the physical model of the plasma-jet system.     

Effect of Low-Pressure Radio Frequency Plasma on Knitted Fabrics Made of Natural Cellulose Fibers

The effect nonequilibrium low-temperature plasma has on knitted fabric made of natural cellulose fibers is considered. It is shown that plasma treatment improves the hydrophilicity of the material and can replace the liquid preparation of knitted fabrics for dyeing.     

Simple Emission Model of Supersonic Molecular Beam

Recently some modes of supersonic molecular beam injection （SMBI）have been put forward. Among them there are electrostatic “double layer”-shielding, simple collective and optimized numerical models to explain the experiment phenomenon. The penetrated depth A and particle deposition were calculated theoretically. About 1/7 in- cident thermal electron flux was amputated and, A increased seven times. The previous simulation is not enough for the SMBI fueling mechanism research. Hence, further investigations, both in experiment and in theory should be developed. The phenomena of line emission due to supersonic molecular beam （SMB） are of particular importance.     

Studying the Generation Stage of a Plasma Jet in a Plasma Focus Discharge

A dense compact plasmoid generated at the pinch collapse stage is revealed in a plasma focus discharge by laser optical methods. The initial size of the plasmoid is ~1 mm, its electron density is more than 2 × 10¹⁹ cm^–3, and the plasmoid propagates along the axis from the anode at an average velocity of more than 10⁷ cm/s. A shock wave is generated in the residual argon plasma during the motion of the bunch, its density decreases to 10¹⁸ cm^–3 at a distance of 3 cm from its place of generation, and the plasmoid expands by 3–5 times and almost merges together with the leading edge of the shock wave.     

Laser-Desorption Supersonic Jet Spectroscopy of Phthalocyanines

The laser-induced fluorescence excitation spectra of zinc phthalocyanine, chloroaluminum phthalocyanine, magnesium phthalocyanine, and free-base phthalocyanine have been investigated under jet-cooled conditions, by using pulsed infrared laser desorption as the means of vaporization. Assignment of the observed vibronic transitions reveals that many of them gain intensity from coupling of the S1(Q) state with the S2(B) and Q' states. Low-frequency out-of-plane modes of the macrocycle are observed in the region below 100 cm-1; the vibronic structure in this region of the spectrum is sensitive to deviation of the molecule from a planar geometry. The S1-S0 excitation energy shows a weak dependence on the hole size of the macrocycle. Copyright 1999 Academic Press.     

Spectroscopic Measurements of Plasma Temperatures in a Radio Frequency Discharge

Argon and mixtures of argon with CH₄, C₂H₂ and N₂ have been excited in a 27.2 MHz radio frequency discharge at pressures of 10 and 5 Torr. Plasma spectra have been recorded and analyzed. The excitation temperatures of Ar I and H, the C₂ and CN vibrational temperatures and the N₂ and CN rotational temperatures have been determined and discussed.     

射频等离子体对气相生长碳纳米纤维的氧化改性

"采用不同流量比率的氧气和氩气作为载气,氧化修饰气相生长碳纳米纤维(VGCNFs)．傅立叶红外光谱、热重以及Boehm's滴定法分析结果表明,当氧气含量为4%时,碳纤维表面生成有大量O-H官能团;然而,当氧气含量增加为5%时,在其表面不仅生成有-OH官能团,而且还有-CHx、-CO等官能团出现,说明在适当的氧浓度条件下有利于VGCNFs修饰;但氧气含量继续增加到8%时,其纤维内层石墨晶格氧化断裂,微晶结构被破坏．"     

Extended Cylindrical Low-Pressure Arc Discharge Plasma Emitter for Generation of a Radially Diverging Electron Beam

Russian Physics Journal - The paper presents the results of studies of processes of generation of a beam-plasma formation in an extended cylindrical hollow mesh anode with a diameter of 115 mm and...     

利用光学方法研究单针射流等离子体的产生和发展机制

对单针电极射流等离子体产生和发展过程中的光信号进行了研究。首先发现等离子体的长度并不是随外加电压升高而增加,而是和驱动电源的能量在正半周放电脉冲之间的分配有关。通过研究等离子体通道内不同位置的发光信号,发现正半周期第一次放电脉冲是在针尖电极处产生,而第二个脉冲是在等离子体通道中部产生,电子激发温度也是在等离子体中部达到最高。通过分析发现,空间电荷产生的附加电场对于等离子体的产生和发展有着重大影响。     

Generation of Plasma with Increased Ionization Degree in a Pulsed High-Current Low-Pressure Hollow Cathode Discharge

Russian Physics Journal - The paper presents the results of research of the processes of generation of pulsed beam-plasma formations in a high-current non-self-sustained glow discharge with a...     

Plasma Behavior with Hydrogen Supersonic Molecular Beam and Cluster Jet Injection in the HL-2A Tokamak

After more than ten years of practice, SMBI has been developed to become a useful fuelling method that is already considered to be an improvement over conventional gas puffing （GP）. The HL-2A tokamak is the first tokamak with divertors in China. The main parameters of HL-2A are R = 1.65 m, α=0.4 m, BT=2.8 T and Ip=0.48 MA. The divertor of the machine now is operated with lower single null configuration. Large hydrogen cluster （〉100 atoms） can be produced at low temperature gas.     

三维超声速射流火焰的直接模拟研究

本文使用了直接模拟（DNS）程序计算了三维超声速湍流射流火焰。首先介绍了本程序使用到的计算方法,包括热物性参数和输运参数的计算、反应机理、边界条件、离散方法。然后,本文使用该方法计算了马赫数为1.2的三维超声速H₂-AIR湍流射流火焰,描述了火焰的整作结构。最后,本文对火焰底部的稳燃的机理—自燃进行了分析和论证。     

A Simple Model for Flashboard Plasma Expansion

A simple model for flashboard plasma expansion is presented. It is based on the j × B force and the fact that only a fraction a of the total current flows through the expanding plasma. For the parameters under consideration, maximum velocities are roughly proportional to a and reach 70 cm/?s for ? = 1. B-field profiles from the model are compared with experiment.     

Orbital Angular Momentum Generation Using Circular Ring Resonators in Radio Frequency

Electromagnetic field generators based on circular ring resonators,whose perimeters are integer times of equivalent wavelength,are well known to have attractive potential for producing radio vortexes carrying orbital angular momentum(OAM).We study the radiation characteristics of the generators based on radiation vector and antenna array theory.The behaviors of radiation patterns,field intensity and phase distribution are investigated in detail,and show classical features of OAM beams.The evolution of the generators performance versus the OAM state is also analyzed.The proposed generators can be realized by all kinds of microwave transmission lines,verified by two different prototypes.The discussions and conclusions drawn in this study are useful and meaningful for the radio OAM generator design.     

Dielectric Characteristics for Radio Frequency Waves in a Laboratory Dipole Plasma

Transverse and parallel dielectric permittivity elements have been derived for radio frequency waves in a laboratory dipole magnetic field plasma. Vlasov equation is resolved for both the trapped and untrapped particles as a boundary value problem to define their separate contributions to the dielectric tensor components. To estimate the wave power absorbed in the plasma volume the perturbed electric field and current density components are decomposed in a Fourier series over the poloidal angle. In this case, the dielectric characteristics can be analyzed independently of the solution of the Maxwell's equations. As usual, imaginary part of the parallel permittivity elements is necessary to estimate the electron Landau damping of radio frequency waves, whereas imaginary part of the transverse permittivity elements is important to estimate the wave dissipation by the cyclotron resonances. Computations of the imaginary part of the parallel permittivity elements are carried out in a wide range of the wave frequencies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Generation of Plasma Wave at Pump-Wave Frequency and Second Harmonic Generation at Ultrarelativistic Laser Power

In this paper, the influence of ponderomotive and relativistic nonlinearities on the filamentation of an ultraintense laser pulse is investigated in three dimensions within the paraxial ray approximations. Generation of electron plasma wave (EPW) structure at pump-wave frequency and the second harmonic generation in these filamentary structures are reported. The generation of the plasma wave is due to intensity gradient (in the transverse direction of the laser beam in filamentary structure) and density gradient (due to ponderomotive-force effect). For typical laser–plasma parameters: The $hbox{laser intensity} = 2.5timesbreak 10^{20} hbox{W/cm}^{2}$; the $hbox{particles density} = 1.9 times 10^{19} hbox{cm}^{-3}$; and it is found that the maximum intensity of EPW is in the range of $2.0 times 10^{13} hbox{W}/hbox{cm}^{2}$. Interaction of the plasma wave with the incident laser beam leads to second harmonic generation, and the yield comes out to be $approx! 2.1 times 10^{-7}$.      

Rotationally-Resolved Excitation Spectroscopy of the Methoxy Radical in a Supersonic Jet

Abstract

Laser-induced fluorescence excitation spectra of the methoxy radical have been obtained under sufficiently high resolution in a supersonic jet expansion. The rotational structure associated with its origin band has been identified in the midst of strong overlapping rotational transitions due to the hydroxyl radical in the 31490–31700 cm^?1 spectral region. Rotationally-resolved A ²A₁ - X ²E spectra of the 0₀ ⁰ band of methoxy have been explicitly assigned using the nomenclature for prolate symmetric top transitions in doublet states.     

射频等离子体增强化学气相沉积SiNx薄膜的研究

采用射频等离子体增强化学气相沉积技术,以N2和SiH4作为反应气体,在P型硅基片上进行SiNx薄膜的沉积.使用椭偏仪对薄膜厚度和光学常量进行了测量, 用傅里叶变换红外光谱仪对SiNx薄膜的化学键合结构进行了分析.研究了基片温度、射频功率以及N2和SiH4的气体流量比率等实验工艺参量对薄膜沉积速率和光学常量的影响.结果表明,射频等离子体增强化学气相沉积技术沉积的SiNx薄膜是低含氢量的SiNx薄膜,折射率在1.65~2.15之间,消光系数k在0.2~0.007之间,当SiNx薄膜为富氮时k≤0.01,最高沉积速率高达6.0 nm/min,N2和SiH4气体流量比率等于10是富硅和富氮SiNx薄膜的分界点.