高压电场技术及其在农业领域中的应用

目的综述高压电场技术及其在农业领域中的应用,并总结其优缺点和未来的发展趋势。方法介绍高压电场技术的基本原理、典型高压电场处理装置,分析不同高压电场的电极类型,以及高压电场技术应用研究的新进展。结果高压电场电晕放电属于一种尖端放电的物理现象,起到了抑菌、促萌发、抗氧化等生物效果;并减少了食品冷冻损伤,加快了食品干燥速率;提高了工业除尘效率。结论高压电场技术在食品领域应用广泛,但电离空气产生的臭氧以及破坏细胞组织结构都会产生副作用。未来需要从高压电场的作用机理出发,进行学科领域交叉性研究,拓宽高压电场在各行业的利用,例如,打印机、船体除垢、电池、燃料控制等方向。     

Adsorbed molecules form ordered structures on the surface of metals exposed to an electric field

Submonomolecular films deposited onto a metal surface in an electric field exhibit the phenomenon of self-organization. The ordering is manifested by the formation of molecular chains featuring the mass transfer. This results in the appearance of a stable dynamic network structure, which exists within a certain optimum temperature interval. It is suggested that this phenomenon is related to the electric interactions in a system of dipoles, one end of each dipole being free and another moving on the substrate surface with friction. Modeling of the evolution of this system with time qualitatively agrees with the experiment. These results can be used in high-voltage and vacuum electronics, space technologies, and nanoelectronics.     

Addressing a model of multistreamer switching in high-voltage silicon <Emphasis Type="Italic">p-n</Emphasis> junctions above the Zener breakdown threshold

It is shown that a model of multistreamer switching from the blocking to conducting state in high-voltage diode structures cannot consistently explain the phenomenon of ultrafast switching of such silicon structures into the conducting state, which was experimentally observed in the rapid growth of the reverse bias voltage in strong (～1 MV/cm) electric fields.     

一种用于高压探头校准的高压快沿脉冲信号产生方法

针对现有快沿脉冲信号幅度不足,无法有效实现高压探头上升时间参数测量的难题,提出了一种高压快沿脉冲信号的产生方法。该方法基于单传输线型脉冲成形原理,使高压脉冲信号在传输线上进行传播,最后在匹配的大功率阻抗上产生一个具有明显顶部特征的矩形波。测试结果表明该矩形波幅度可达2kV,前沿的上升时间小于500ps。通过对两款高压探头上升时间参数进行测量,实验结果验证了该方法产生的高压快沿脉冲信号适用于高压探头上升时间参数的校准。     

真空高压器件脉冲老炼台的研制

真空高压器件脉冲老炼台由可调直流高压电源、储能器、高压脉冲变压器、高压开关、控制器、真空计、存贮示波器、限流电阻箱、极性转换器、高压击穿判别及高压脉冲分压器等构成，在线测量真空高压器件内的真空度和高压脉冲电压幅度、检测高压击穿状况，高压脉冲电压幅度连续可调、限流电阻和脉冲正负极性自动转换，性能稳定可靠。     

High-energy proton generation under surface discharge conditions

A combined nanosecond pulsed electric discharge, whereby the breakdown proceeds simultaneously over a dielectric surface and across the interelectrode gap, has been studied. A beam of accelerated protons is generated in this system with a maximum energy of up to 350 keV that exceeds the high-voltage source potential. The phenomenon of selective acceleration of hydrogen ions has been observed. It is established that the probability of ion generation depends on the electrode polarity.     

10kV/1000A高压电能计量标准及其量值溯源的研究

为了保证高压电能测量量值的准确可靠,提出了建立10kV高压电能计量标准及其量传系统的新方法,以实现高压电能计量器具的室内计量检定,进而实现电网高压电能计量器具的量值溯源。基于I/V和V/V技术,研制了高压电能计量标准,并对研究成果进行了不确定度分析及溯源验证,其三相电能的测量准确度达到0.02%;以高压电能计量校准装置作为被检对象,其三相电能的测量准确度在功率因数PF为0.5时达到0.12%。     

Advances in triboelectric nanogenerator powered electrowetting-on-dielectric devices: Mechanism,structures, and applications

Electrowetting-on-dielectric (EWOD) phenomenon is widely employed for liquid actuation at the micro scale. Due to its simple structure, low cost, low power consumption and fast response speed, diverse applications are developed and commercialized based on EWOD, such as digital microfluidics, tunable lenses, electronic displays, small-scale propellers etc. However, the liquid actuation with EWOD requires a high-voltage but low-current power source. The accessory equipment (e.g., waveform generator and amplifier) not only attenuates the benefits originated from microscale liquid actuation, but also limits its portability, wearability, and environmental friendliness of the EWOD inspired applications. Triboelectric nanogenerator (TENG) is a promising technology to convert arbitrary mechanical energy to electricity based on triboelectrification and electrostatic induction. The output electric signal shows a high-voltage but low-current property which well matches the demands in EWOD devices. This paper reviews the technical advances in the TENG powered EWOD devices developed in recent years. The mechanisms, structures, and performance of each application are reviewed. The challenges and future perspectives are put forward. The review and discussion in this study open up opportunities for the development of TENG and EWOD based self-powered liquid actuators.     

Fractal spatial structure of lightning discharge and its relation to the structures of high-voltage discharges of other types

The fractal dimension of a lightning discharge is determined. It is established that, with respect to the fractal dimension and, hence, the character of spatial structure organization, the lighting discharge is analogous to high-voltage discharges of other types, including streamer corona, surface, nanosecond diffuse, spark, and streamer-free discharges. This analogy leads to a conclusion concerning the generality of physical mechanisms involved in the self-organization of various high-voltage discharges.     

Strength distribution of titania ceramics after high-voltage screening

Screening fields, at or below which 10%, 30% and 50% of TiO₂ ceramic samples would break electrically, were applied to samples which show single-mode strength distribution. After these high-voltage screenings, the surviving samples were subjected to mechanical strength measurement and the resultant strength distributions were compared with the original distributions. This high-voltage screening was also applied to model ceramics samples composed of titania with two different relative densities. The effect of high-voltage screening and the correlation between mechanical and dielectric strengths are discussed.     

Spectral measurements of the gas and electron temperatures in the flame of a single-phase ac plasma generator

High-power electric-arc ac plasma generators find extensive application which is primarily associated with the problem of processing of organic waste and production of synthesis gas. The structure of a high-power single-chamber multiphase ac plasma generator with rail-type electrodes includes an injector of primary charge carriers which is a single-phase high-voltage plasma generator with a power of 10 kW or lower. This latter plasma generator may be further employed for solving other problems. Results are given of spectroscopic measurements of gas temperature fields at the nozzle exit section of a high-voltage plasma generator with rod electrodes located in a cylindrical channel. The pattern of variation of the temperature fields as a function of working gas flow rate is investigated.     

冲击高压分压器高压臂用卡玛丝温度系数影响因素的研究

用于冲击高压分压器高压臂的卡玛丝,需将其均匀密绕于绝缘骨架上,然而,骨架的引入会给卡玛丝的温度系数带来影响。理论和实验证明骨架的热膨胀系数及其几何形状对卡玛丝产生的弯曲应变是改变卡玛丝温度系数的主要影响因素:当骨架的热膨胀系数大于材料本身的热膨胀系数时,温度系数的测量结果会大于电阻丝本身真实的温度系数;弯曲应变会引起K状态结构的破坏,使得电阻值减小。     

Solid nanocrystalline fullerite-containing carbon coatings

Solid carbon coatings with a high content of nanocrystalline fullerite have been obtained using unbalanced magnetron sputtering of graphite under conditions of pulsed high-voltage ion bombardment of the film growing on a substrate. It is established that samples possessing the maximum hardness (18.8 GPa) are characterized by maximum values of the volume fraction of fullerite in the coating (50%), coherent scattering domain size (53 nm), degree of preferred grain orientation (85%), relative deformation of the lattice (1.02%), and internal compressive stresses (2.91 GPa). The observed behavior is consistent with the mechanism of strengthening that accounts for the phenomenon of superhardness in nanocrystalline and nanocomposite materials. This assumption is confirmed by the results of investigation of the morphology of growing coatings.     

Improved Techniques for the Measurement of High-Voltage Impulses Using the Electrooptic Kerr Effect

The purpose of this paper is to present two methods of accumulating, analyzing, and presenting in real time the data generated by a Kerr system in response to a high-voltage impulse. These methods provide immediate information concerning selected electrical parameters in a form which is easily interpretable by most personnel. The first method uses an electronic counter to determine the number of optical transmittance maxima, i.e., light pulses, duritg the high-voltage impulse. From this count, the peak value of impulse can be calculated. The second method, which can be more accurate and does provide information concerning waveshape, uses a digital recorder to store the output waveform from the Kerr system. A computer is then used to reconstruct the voltage impulse and to determine such parameters as the peak value and risetime of the impulse.     

A High-Voltage Switching Power Supply for Cold Plasma Jets

Technical Physics Letters - The parameters of a number of high-voltage solid-state switches are studied. Based on the analysis of their work, a high-voltage pulse source with a size of 105 ×...     

A Method of Checking High-Voltage DC Potential Dividers

A method of checking high-voltage dc potential dividers based on the use of a supplementary dc potential divider and a voltage comparator as standard means of measurement is considered. The method provides a constructive simplification of the checking system and enables high-voltage dc potential dividers to be checked at voltages of up to 100 kV.     

Electromagnetic screening of the elements of a high-voltage vacuum divider

The efficiency of constructional-technological measures for screening the most vulnerable components of high-voltage vacuum capacitive dividers, which are exposed during use to the destabilizing actions of intense external electromagnetic fields, is estimated.     

Pulse Shape Improvement in Core-Type High-Voltage Pulse Transformers With Auxiliary Windings

High-voltage pulsed power technologies are rapidly emerging as a key to efficient and flexible use of electrical power for many industrial applications. One of the most important elements in high-voltage pulse-generating circuit technology is the transformer, generally used to further increase the pulse output voltage level. However, its nonideal behavior has significant influence on the output pulse shape. The most attractive winding configuration for high-voltage, the core-type transformer with primary and secondary on different core legs, is seldom used in pulsed applications, because of its weak magnetic coupling between windings, which would result in a slow-rising output voltage pulse. This paper shows that auxiliary windings, suitably positioned and connected, provide a dramatic improvement in the pulse rise time in core-type high-voltage pulse transformers. The paper derives a mathematical model and uses it to describe the observed behavior of the transformer with auxiliary windings. It discusses experimental results, obtained from a high-voltage test transformer associated with a high-voltage pulse generating circuit, and the simulation results obtained from the numerical evaluation of the developed differential equations implemented in Matlab and taking into account the measured transformer parameters.      

An active voltage divider for higher frequencies

Conclusion The proposed method can be recommended for the design of single-section screened voltage dividers for voltages of up to several kilovolts, which are intended for use at higher frequencies in checking high-voltage equipment as well as for high-voltage measurements.     

Structure and Properties of the Gypsum Mortar with Silica Sand Under Temperature Load

International Journal of Thermophysics - The electrospray (ES) cooling technique, which is a combination of spray cooling and high-voltage electrostatic technology, has attracted considerable...