Prolonged microbial resistance of water treated by a pulsed electrical discharge

The main characteristics of pulsed discharges in water are studied, such as the discharge current, voltage drop across the discharge gap, temperature of the discharge column, and plasma conductivity, as well as compression waves and ultraviolet radiation, which are induced by the discharge. The physicochemical properties of water treated by pulsed discharges are considered in the context of the effect produced on microorganisms. The mechanism underlying the prolonged microbial resistance of water—its capability of retaining a high activity against virtually all known pathogenic microorganisms and human-opportunistic fungi for many months after the discharge treatment—is explained.     

水中脉冲放电的电特性与声辐射特性研究

对水中脉冲放电等离子体通道电阻与放电参数之间的关系作了研究,得到了等离子体通道电阻与电容量、初始电压、电极间距离的关系,以及通道电阻随时间的变化规律.还对冲击波的峰值压力与放电参数间的关系作了研究,并对冲击波压力的功率谱作了分析,结果表明水中脉冲放电所产生的冲击波的声辐射频率在几十赫兹到几万赫兹之间,覆盖了所有水声设备的工作频率,且在低频段具有很强的声功率,是一种理想的水下声源 关键词： 水中脉冲放电 等离子体     

Stimulated emission of argon dimers excited by a pulsed plasma-cathode discharge

Results are reported from a theoretical and experimental investigation aimed at obtaining lasing on transitions of an Ar₂ excimer laser pumped by a pulsed electric discharge. It is shown that by using a recently developed plasma-cathode discharge, quasi-cw excitation of the laser active medium can be achieved with a gain of around 0.1 cm⁻¹. The results of preliminary experiments performed using a model system indicate an effect wherein the duration of the spontaneous emission at the gl=126 nm transition of the Ar₂ dimer decreases monotonically as its peak intensity increases. This behavior, which is observed with increasing pump intensity, is evidence of a stimulated emission effect in the system. However, the measurements indicate that no amplification takes place in the active medium because of accidental impurities in the working gas. Zh. Tekh. Fiz. 67, 49–52 (November 1997)     

Synthesis of nanoparticles using a pulsed electrical discharge in a liquid

We used a pulsed electrical discharge in a liquid to obtain Cu-, WC-, and ZnO-containing nanoparticles. The effect of the discharge current and pulse duration on the morphology and phase composition of the synthesized material was studied by spectrophotometry, transmission electron microscopy, and x-ray diffraction analysis. We discuss possible mechanisms for nanoparticle formation in a discharge submerged in a liquid. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 111–120, January–February, 2008.     

Decay of the ultraviolet continuum in the afterglow of a pulsed argon discharge

The decay of the ultraviolet continuum in argon has been measured at pressures up to 120 torr. At pressures lower than 20 torr the decay frequency is given by ν_D = 48/Λ²p + 45p + 18.0p².     

Chemical processes in the single-electrode pulsed HF discharge plasma

It is shown that in the discharge plasma of the atomic emission spectrometer, the formation of CN molecules from CO₂ and N₂ takes place. The correctness of measuring the CO₂ concentration from the emission intensity of CN at a wavelength of 388.3 nm in respiratory processes is proved experimentally.     

Time-resolved measurements of shock-induced cavitation bubbles in liquids

A novel experimental method for the measurement of cavitation bubble dynamics is presented. The method makes use of a collimated cw HeNe laser beam that is focused onto a photodiode. A cavitation bubble centered in the laser beam leads to refraction and thus changes the diode signal. With sufficient temporal resolution of the measurement, the evolution of the bubble dynamics, and in particular, the collapse, could be well resolved (limitation is only due to diode response and oscilloscope bandwidth). In the present work this is demonstrated with cavitation bubbles generated with high-power nanosecond and femtosecond laser pulses, respectively. Bubble evolution is studied in two different liquids (water and glycerine) and at different temperatures and pressures.     

Laser-induced modification of composite Cu-C nanosized particles synthesized using a pulsed electrical discharge in a liquid

Composite copper-containing carbon nanosized structures were synthesized in the plasma of a pulsed electrical discharge, initiated between two graphite electrodes in an aqueous copper chloride solution. We studied the effect of laser radiation on the morphology of the nanoparticles formed, whose properties we studied by optical absorption spectroscopy and transmission electron microscopy. We discuss the mechanisms for nanoparticle formation in a discharge submerged in a liquid, and the possibilities for laser-induced modification of the nanoparticles. We estimated the temperature of the nanoparticles when exposed to laser radiation pulses. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 372–378, May–June, 2008.     

不同氩气气压下铝丝电爆炸的二次放电特性

搭建了RLC放电回路,研究了不同氩气气压下铝丝电爆炸二次放电特性。结果表明,随着气压的变化,电爆炸二次放电电压曲线呈U形。为了阐明氩气和铝蒸气在二次放电过程中的作用,利用光谱仪和高速分幅相机分别研究了二次放电等离子体的自辐射光谱特性和空间分布特性,发现:在低气压下氩气会参与放电,放电通道在铝蒸气表面;高气压下主要是铝蒸气放电,氩气基本不参与放电过程,放电通道在铝蒸气内部。     

A time-resolved study of the u-v radiation produced in the initial time period of a pulsed argon discharge

The time development of the integral intensity of ultra-violet radiation from the positive column of a pulsed discharge was studied and the results compared with those for visible light. The measurements were made at various pressures in the range 0·3–4·8 torr. We found that at a pressure about 4 torr the maxima of intensity of the u-v and the visible light occurred at nearly the same time after the initiation of the discharge. On the other hand, at a pressures of about 0·5 torr the positions of the maxima were different.     

Ignition of hydrocarbon films by a pulsed discharge propagating above a water surface

We present the results of experimental investigations into the ignition and combustion of hydrocarbon films deposited on a water surface by a pulsed discharge propagating above the liquid in motionless air under atmospheric pressure.     

水中针-板结构小能量脉冲火花放电特性北大核心CSCD

开展了J量级系统储能下电脉冲参数对水中火花放电特性影响研究。驱动源采用参数可调的固态重频纳秒脉冲电源,放电负载为水中针-板结构(间距1 mm),在低重频条件(约5 Hz)下进行实验。通过调节放电参数、拍摄高速阴影图像、光谱诊断以及声信号测量,研究水中脉冲放电的物理特性,得到不同放电参数下放电演化规律及其对声学、光谱特性影响。实验发现:在J量级储能下,放电通道连通两极后,回路电流在几百ns内快速上升至10 A左右,随后缓慢下降,持续50~60μs。发现预设脉宽对放电影响较大,短脉宽条件下放电会被电源固态开关强制截断出现反向放电,而长脉宽条件下放电通道在后期变得不稳定甚至熄弧中断,出现气泡中二次放电现象。辐射光谱揭示了更多等离子体信息,推断通道电子密度在1018 cm-3量级,随着脉宽增加,特征谱线强度增加,表明活性粒子数密度增加,但粒子种类不变。短脉冲(<150μs)作用下产生的脉冲声波的特征宽度在110~150μs,而当脉宽继续增大,声波脉宽并不继续增加而是保持不变,保持在150μs左右。研究结果对水中小能量火花放电的机理研究有一定参考价值,为水声学、液相等离子体等领域的应用提供思路。     

氩气介质阻挡放电不同放电模式的电学特性研究

采用水电极介质阻挡放电装置，在气压为40kPa的氩气中实现了弥散、流光和斑图三种不同 模式的放电，并对其光电特性进行测量.通过测量测试电容上的电压，从而将气隙电压计算 出来，发现随外加电压增加，放电起始时刻不断提前，放电占空比增加；对应放电时刻，气 隙电压减小、输运电荷突增，使得气隙电压和电量波形都远远偏离正弦.气隙电压与输运电 荷成非线性关系.给出了外加电压零点对应的气隙电压随外加电压峰值的变化关系.讨论了壁 电荷在放电中的作用及对气隙电压和电量波形的影响. 关键词： 介质阻挡放电 气隙电压 自组织斑图 输运电荷     

Rates and channels of water ionization by a high-current high-voltage pulsed discharge

The experimentally observed growth of the plasma density in a high-current high-voltage pulsed discharge in a liquid medium is compared with the results of calculations based on the effective cross sections for electron-impact ionization and other elementary processes. It is found that, in the initial stage of the discharge, the plasma density grows linearly with time, whereas at densities above 3 × 10¹⁰ cm^?3, the growth becomes exponential due to the collective acceleration of plasma electrons. The gas-vapor fraction of the water medium is ionized by two groups of electrons: low-energy electrons, with energies about several tens of electronvolts, and high-energy ones, with energies in the kiloelectronvolt range. The energy spent on water ionization is estimated and is found to be several times higher than the energy required to ionize a rarefied gas.     

Time-resolved electrical and optical measurements in a plasmadisplay panel

We have used a commercially available monochrome plasma display panel (PDP) to study the electrical and optical properties of PDPs. The monochrome PDP was filled with helium at a pressure of 0.5 atm with the visible light emission observed directly from the gas discharge. The PDP is driven by an AC voltage source, operating at ~130 V at 50 kHz. With nanosecond resolution we have measured the current in the panel and the spectrally resolved light emission from the panel as a function of applied voltage. This study of a helium-filled conventional PDP is designed to provide data needed for improved modeling calculations of the plasma discharge. The ultimate goal is to achieve improved designs and efficacies for large-screen color PDP's     

Decoloration of azo dye by a multi-needle-to-plate high-voltage pulsed corona discharge system in water

The decoloration efficiency of azo dye (Acid Orange 7, AO7) using a multi-needle-to-plate high-voltage pulsed corona discharge system was investigated in this paper. The effect of several parameters, including peak pulse voltage and pulse frequency of the discharge system, initial pH and electrical conductivity of the dye solution, mode of needle electrode distribution and gas flow rate on the decoloration rate of the dye wastewater was reviewed. The results obtained show that the pulsed discharge system with a multi-needle-to-plate electrode could dispose azo dye wastewater efficiently. The decoloration rate increased with an increase in applied peak pulse voltage and pulse frequency. Decoloration was more efficient in the acidic solution, and the decoloration rate displayed no marked change under solutions of differing electrical conductivity. For the case in which we example the effect of gas flow rate on the decoloration efficiency of Acid Orange solution, we found that better decoloration efficiency occurred using the seven-needle-to-plate discharge system, which had more discharge anodes.     

脉冲气体放电管特性测量实验

用TDS210型存贮示波器测量了脉冲气体放电管(闪光灯)的放电特性，同时用PIN型硅光电池测量脉冲光的波形，测量了它们之间的延迟，并计算了脉冲气体放电管的动态电阻，讨论了放电过程从触发到结束的物理图象．