Two-dimensional simulations of plasma flow and charge spreadingacross barrier pixels in AC plasma displays

Two-dimensional multispecies simulations of adjacent pixels separated by a barrier height 80% the gap height in a plasma display pixel cell are performed. The fill gas pressure is 400 torr with 2% xenon in helium. The simulations using a minimum number of excited states of helium and xenon are performed for different cell widths representing different display resolutions. The simulations show plasma transport through the gap to the adjacent pixel which is in the sustained off state. In a sustained off state, there is no discharge in the pixel at the sustained voltage. The simulations show that for low-resolution displays, the plasma overflow does not cause a discharge in the adjacent pixel that is in the sustained off mode, while for a high-resolution display a 20% gap in the barrier height could result in a breakdown in the adjacent off pixel. A higher pixel resolution, or equivalently smaller pixel pitch. requires higher firing and sustained voltages due primarily to increased particle losses as a result of the reduced particle transit times. Finally, using a larger number of excited xenon atomic states including the xenon [6s, j=1] and [6s', j=1] radiative states and the molecular xenon dimer, an isolated single pixel is simulated to model the transport of excited states including the radiative states. The model shows that the density profiles peak in the cathode fall region spreading out to the side walls with decreasing intensity     

New color-enhancing discharge mode using self-erasing discharge in AC plasma display panel

A new color-enhancing discharge mode using a self-erasing discharge is proposed based on an analysis of the Ne emission mechanism in a Ne-Xe gas mixture. The effects of the new color-enhancing discharge mode produced by a ramped-square sustain waveform on improving the color reproducibility are examined in an alternate current plasma display panel (ac-PDP) filled with a Ne-Xe gas mixture. When the ramped-square sustain pulses are applied at 150 kHz, the color purities of the blue and green visible emissions are both improved, thereby expanding the color gamut area by about 5.4% without reducing the luminance.     

Dusty plasma structures in He-Kr DC glow discharge

Ion drift in gas mixtures has certain properties that can be used to generate ion flows with desired characteristics. For example, when the field is strong, ion heating is significant, and there is a large difference in atomic weight between ions and atoms, the ion velocity distribution can be highly anisotropic. Ion distribution anisotropy, in turn, can cause a substantial change in properties of dust structures in plasmas. Experiments on dusty plasma structures in glow discharge in mixtures of light and heavy gases (helium and krypton) are performed, and results of numerical simulations of ion and electron drift in the mixture are presented.     

An effective approach for designing a low pressure DC glow discharge plasma reactor

Most plasma reactors are designed for research purposes and they are less appropriate for industry. To facilitate the engineering of an industrial reactor, an effective approach based only on the calculated Paschen curve, the simulation of the electric field and the breakdown reduced field is proposed. The results show that the experimental Paschen curve is different from the theoretical one; consequently the recalculation of the electric parameters is discussed. The experimental voltage/Current characteristic is used to identify the abnormal glow discharge regime and also to correlate the visual aspect of the discharge with its regimes.     

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采用浓度调制光谱技术研究了连续交流放电产生的氮等离子体喷束。当放电峰峰电压VPP大于9.6kV时,氮离子以脉冲形式产生,每个放电电压周期产生一次。此时监测到交流放电电流上有一反向电流尖峰,该电流尖峰是等离子体喷束中氮离子惯性运动形成的,其强度与浓度调制光谱的强度成正比。根据浓度调制光谱的1f/2f检测结果,提出了一个理论模型,解释了上述现象。     

Dusty plasma structures in magnetic fields in a dc discharge

The formation of dusty plasma structures has been experimentally investigated in a cylindrical dc discharge in axial magnetic fields up to 2500 G. The rotation of the dusty plasma structures about the discharge symmetry axis with a frequency depending on the magnetic field has been observed. When the field increases to 700 G, the displacement of dust particles from the axial region of the discharge to the periphery, along with the continuation of the rotation, has been observed. The kinetic temperatures of the dust particles, the diffusion coefficients, and the effective nonideality parameter have been determined for various magnetic fields. The explanation of the features in the behavior of the dust particles in the discharge in the magnetic field has been proposed on the basis of the analysis of ambipolar diffusion in the magnetized plasma. The maximum magnetic field at which the levitation of the dust particles in the discharge is possible has been estimated.     

Circuit model for two-electrode AC discharge

This paper presents a circuit model for a two-electrode AC discharge, which has two electrodes separated from the discharge gap by an insulator. The model consists of a series connection of an equivalent circuit for plasma and two capacitors for insulator. The equivalent circuit for plasma was constructed using the measured electrical properties of a two-electrode DC discharge. The validity of model was checked with experiments on a three-electrode test device; two electrodes exposed to the discharge gap and the other electrode separated from the discharge gap by an insulator. The measured voltages of the test device are compared with those obtained by circuit simulation. For various waveforms, which are being used widely to drive an AC plasma display panel, the results of circuit simulation agree well with experiment.     

Migration of sodium in an AC discharge

The mechanism of migration of sodium in the positive column of a low-pressure discharge at a frequency of 25–400 Hz is studied. It is established that the mass transfer of sodium in the discharge channel results from diffusion of sodium atoms and ions in the electric field. It is shown that as the grid frequency increases the amplitude of the oscillatory motion of sodium ions decreases. The possibility of restricting the migration of sodium along the discharge tube by creating an artificial temperature drop in it is confirmed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 3–9, February, 1985.     

Propagation of a high-pressure microwave discharge in prebreakdown fields: Formation of plasma structures

A 3D model is developed, which describes the propagation of an initiated high-pressure microwave discharge in a linearly polarized wave beam. The equations for the electric field amplitude are solved self-consistently with the set of equations of plasmochemical kinetics. Plasma structures of the experimentally observed “snake” and “chain” types are obtained using this model. The calculation results enable one to determine the conditions of formation of one or another spatial structure, as well as the parameters of the plasmoids being formed. The results of calculation of the discharge propagation toward the radiation source are compared with the available experimental data.     

An efficient time-integration method for nonlinear dynamic analysis of solids and structures

This paper presents an efficient time-integration method for obtaining reliable solutions to the second-order nonlinear dynamic problems in structural engineering. This method employs both the backward-acceleration differentiation formula and the trapezoidal rule, resulting in a self-starting, single step, second-order accurate algorithm. With the same computational effort as the trapezoidal rule, the proposed method remains stable in large deformation and long time range solutions even when the trapezoidal rule fails. Meanwhile, the proposed method has the following characteristics: (1) it is applicable to linear as well as general nonlinear analyses; (2) it does not involve additional variables (e.g. Lagrange multipliers) and artificial parameters; (3) it is a single-solver algorithm at the discrete time points with symmetric effective stiffness matrix and effective load vectors; and (4) it is easy to implement in an existing computational software. Some numerical results indicate that the proposed method is a powerful tool with some notable features for practical nonlinear dynamic analyses.     

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空气中的大气压辉光放电通常因放电易过渡到火花状态而难以产生。在静态大气压空气针-板等离子体发生器中，采用阻容耦合负反馈方法控制等离子体放电发展过程，成功地抑制了辉光放电向火花放电的过渡，产生了稳定的交流辉光放电。研究了电压、电极间距等参数变化对放电的影响。     

某型无人机收发信机静电放电防护加固

无人机交换机芯片易被静电放电(ESD)电磁脉冲损坏,严重影响无人机数据链正常通信。针对此问题,通过搭建人体-金属ESD电路模型并进行仿真分析,发现所选用的TVS防护器件对15 kV等级的ESD防护效果显著。分别对加装TVS防护器件前后的收发信机电路进行了ESD电磁脉冲抗扰度对比试验。试验结果表明,加装防护器件后的电路对ESD电磁脉冲的防护能力最大提升7.4倍。     

An analysis of acoustic oscillations in dust plasma structures

Low-frequency oscillations in the density of dust particles, which are spontaneously excited in the standing plasma column of a dc glow discharge in neon, were experimentally studied. The longitudinal waves were monitored by a special visualization technique, and the dust sound oscillation characteristics were determined and analyzed using specially developed algorithm and data processing software. It was established that the longitudinal waves propagate from anode to cathode, the frequency and wavevector of the dust sound oscillations being dependent on the discharge current, gas pressure, particle density in the dust cloud, and spatial coordinates. Two-dimensional (2D) fields of the main wave characteristics were studied using an original algorithm. The possible mechanisms of excitation of the dust sound oscillations is discussed. The experimental spatial distributions of the wave parameters are compared to the patterns obtained within the framework of various theoretical models.     

The block Schur algorithm for designing optical multi-layered structures

We present how to use the block Schur algorithm to design optical multi-layered filters. The block Schur algorithm can, in turn, be applied to find reflection coefficients of optical multi-layered filters. We show that the block Schur algorithm using the block matrices is faster than the standard Schur algorithm using the scalar elements on vector processor. The optimum sub-matrix size for the block Schur algorithm on CRAY Y-MP C98 supercomputer is also suggested.     

Electrostatic waves in a paired fullerene-ion plasma

Three kinds of electrostatic modes are experimentally observed to propagate along magnetic-field lines for the first time in the pair-ion plasma consisting of only positive and negative fullerene ions with an equal mass. It is found that the phase lag between the density fluctuations of positive and negative ions varies from 0 to pi depending on the frequency for ion acoustic wave and is fixed at pi for an ion plasma wave. In addition, a new mode with the phase lag about pi appears in an intermediate-frequency band between the frequency ranges of the acoustic and plasma waves.     

HL-2M初始等离子体放电阶段的辉光放电清洗系统电极的设计与分析

针对HL-2M装置初始等离子体放电阶段所需的直流辉光放电清洗系统的电极进行了设计.对辉光放电清洗系统在不同工况下的系统负载进行了分析和拟定,并确定了电极结构设计分析标准.根据系统电极的结构特点并结合系统负载规范与分析标准,依据不同的失效模式对电极进行了失效分析.分析结果表明,此针对初始等离子体放电的电极设计能可靠安全运...     

Proposing an efficient algorithm for designing universal nanoelectronic molecular logic gates

In today's world, there are still demands for minimising the dimensions of electronic circuits, the result of which is designing nanoelectronic circuits and very small molecular gates and switches. The point which causes trouble in this design is high impact of different parameters on the performance of circuit. Despite the suggestion of simple electronic circuits and different gates, impact of parameters like length of molecule, angle between different atoms, coupling situation of electrodes to molecule, the type of atoms used in a molecule's structure and other cases has made their development almost impossible. In this paper, there was an attempt to study previous works in order to, first, mention the effects of different conditions on circuit performance and, second, present an algorithm for designing gates so as to minimise the effects of these parameters on circuit performance.     

Glow discharge plasma electrolysis for nanoparticles synthesis

There are many methods available to synthesize nanomaterials and the glow discharge plasma electrolysis is a novel and a green method in this category. It is seen that most of the papers are published after 2005 and the interest in it is growing due to its applicability in the industry for preparing nanomaterials at large scale. But, only few results are available yet and most of them are on metal nanoparticle preparation, so that more studies are needed to understand the nature of growth of the nanoparticles under glow discharge in liquid and its applicability in preparing semi-conductor nanomaterials. Many have tried many methods to prepare nanoparticles by the glow discharge and a review like this is the need of the time to understand its present status that helps to modify the present situation to a better one. This review classifies all the available methods of nanomaterials synthesis in liquid by glow discharge in to three and it is discussed in detail.     

脉冲放电弧光等离子体演示仪

介绍了一种脉冲放电弧光等离子体演示仪.该设备内置的测量电路可以直接显示放电电压、电流的大小和放电的持续时间,放电电流也可以通过附带的感应线圈来测量;结合光栅光谱仪,可以测出发光光谱,进而求出等离子体的温度、密度等参数.     

液相放电等离子体特性与激波特性的数值分析

以能量平衡方程为基础,采用不同的电导率唯象模型描述了液相放电等离子体圆柱形通道特性,得到了通道内半径、温度、电阻、电流和耗散能量随时间的变化关系,还给出了距离放电间隙中心一定距离处的冲击波压力变化,并与前人利用等离子体通道球状模型计算得到的结果进行了比较。结果表明：把等离子体通道看成球状和看成圆柱状在描述通道压力和通道半径时差异显著,而在描述其他物理特性时差别不大;三种电导率模型在描述等离子体通道物理特性时,变化趋势大体相同,而在描述激波特性时,电导率模型σ₂更符合实际;通过对比电学参数与压力参数的变化,就可以在实验中根据实验数据以及具体的研究问题进行模型的适用性选择。