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高压静电场促进植物生物技术的研究 总被引:2,自引:0,他引:2
高压静电场促进植物生长技术源于自然又高于自然。它包括静电种子处理和静电场生长环境等技术。文章论述了该技术的实施方法,并报道了 取得的初步成果。 相似文献
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静电场对红细胞悬液冻结特性的影响 总被引:2,自引:0,他引:2
本文以红细胞悬液为研究模型,通过在对其进行慢速冻结的过程中引入静电场,具体研究了静电场对降温过程中红细胞悬液冻结特性的影响。实验结果表明:静电场在一定程度上改变了冰晶的形成与生长特性,抑制了晶核的形成, 使晶枝出现不对称生长,并减缓了冰晶的生长速度,这些影响随着场强的增加而逐渐加强。在较强的静电场的影响下,冰晶明显变粗,最终成为块状,细胞也不再与冰晶分离而是完全融入粗大的冰晶之中,在冻结的末期,细胞不再受到冰晶挤压,从而减少了其所受的机械性损伤。 相似文献
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通过对几个具体的典型的复杂静电场、静磁场边界条件的求解,论述了求解复杂静电场、静磁场边界条件的一般方法.并就目前一些电动力学教科书上一些相关静电场、静磁场边界条件的结论进行了分析与讨论. 相似文献
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“近场强远场弱”是静电场的普遍特点,宏观带电体的静电场是点电荷电场叠加的结果.本文以静电场中两个实际的电场强度问题为例,用相对数值比较了电荷分布对电场强度的贡献,阐述电场强度“近场强远场弱”的数值意义. 相似文献
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《电磁学》自学辅导材料(二) 总被引:1,自引:0,他引:1
第二章静电场中的导体和电介质 在第一章里,建立了静电场的描述,讨论了静电场的基本性质和规律.只要电荷是静止的,电场就是静电场,这些性质和规律都普遍适用。在那里,没有涉及到电荷是如何获得的,而且在空间除了电荷之外.不存在任何物质.在本章将进一步涉及到携带电荷的物质,即考虑空间存在导体和电介质的情形,这就需要进一步考虑电场与导体和电介质的相互作用问题.由于本章仍然限于讨论静电情形,第一章静电场的基本性质和规律都适用,因此本章内容是第一章的深入和发展.此外,这一章还讨论了静电场的能量问题. 下面分三个方面来研究本章的主… 相似文献
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电场对含水物料中水分子作用的研究进展 总被引:4,自引:0,他引:4
电场解冻、电渗透脱水、高压电场干燥三方面的应用研究越来越受到人们的关注 ,是静电研究的一些新领域 ,为脱水与解冻工作开辟了一条新途径 .大量实验表明这三方面应用研究具有物料不升温、很好的保持物料有效成分和不污染环境等许多优点 .文章综述了近年来这三方面研究在国内外的进展与应用成果 ,认为它们的共性都是电场对含水物料中水分子作用的结果 ,并且对此进行了分析 . 相似文献
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本文报道一种基于双层介质界面极化机理的新型驻极体注极技术: 借助辅助层对PP薄膜进行注极. 采用表面电位测试方法考察了注极温度、注极电压对所获PP薄膜驻极体电荷存储性能的影响, 并利用热刺激放电技术研究了其高温电荷存储性能, 同时测试了PP薄膜驻极体在X和Y方向的静电场分布. 结果表明: 界面极化注极是一种比电晕注极更为优异的驻极体形成方法. 在一定温度下, 驻极体表面电位随注极电压的增加而增加, 而且两者呈线性关系, 这一结果与注极过程的电荷积聚方程的分析完全一致. 注极温度的影响研究表明, 在保持注极电压不变(注极电压范围为0.5–3.0 kV)的情况下, 温度低于75 ℃时, 温度的变化对于注极效果的影响不明显; 当注极温度大于75 ℃ 时, PP薄膜驻极体的表面电位随注极温度的增加而增加. 表面电位随时间的变化研究表明, PP薄膜驻极体具有良好的电荷存储稳定性. 对其表面电位分布的测试表明, 界面极化注极所形成的PP薄膜驻极体呈现均匀的静电场分布. 相似文献
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超晶格电流振荡的分岔图和Poincaré映射 总被引:1,自引:0,他引:1
基于超晶格输运的分立漂移模型,数值模拟了掺杂弱耦合GaAs AlAs超晶格在外加交流偏压下电场畴的输运行为.以黄金分割比固定交流驱动频率,模拟并分析不同交流幅度下电流的准周期、锁频及混沌现象. 相似文献
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SiC材料及器件研制的进展 总被引:13,自引:0,他引:13
作为第三代的半导体材料-SiC具有禁带宽度大、热导率高、电子的饱和漂移速度大、临界击穿电场高和介电常数低等特点,在高频、大功率、耐高温、抗辐照的半民体器件及紫外探测器和短波发光二级管等方面具有广泛的应用前景,文章综述了半导体SiC材料生长及其器件研制的概况。 相似文献
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为研究真空环境下电磁场诱发针-板电晕放电特性,研制了电磁场发生器、真空系统、高压静电源、动态电位测试仪等组成的电磁场辐照诱发真空电晕放电模拟试验系统。该系统可实现真空管内气压为80 Pa的低真空环境,并利用此系统进行在电磁场的作用下的电晕放电试验,初步得到了电磁场辐照诱发电晕放电的阈值电压的变化规律。试验结果表明:当温度、湿度等其他环境因素基本不变,真空管内气压为80 Pa时, 正常放电阈值为-590 V, 利用负极性高压静电放电, 电压取值范围10~20 kV, 产生的电磁脉冲辐射作用于真空管内充电区域,可使放电阈值降低90~180 V。 相似文献
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A numerical investigation has been carried out to examine the electrostatic loss of nanoparticles in a corona needle charger.
Two-dimensional flow field, electric field, particle charge, and particle trajectory were simulated to obtain the electrostatic
deposition loss at different conditions. Simulation of particle trajectories shows that the number of charges per particle
during the charging process depends on the particle diameter, radial position from the symmetry axis, applied voltage, Reynolds
number, and axial distance along the charger. The numerical results of nanoparticle electrostatic loss agreed fairly well
with available experimental data. The results reveal that the electrostatic loss of nanoparticles increases with increasing
applied voltage and electrical mobility of particles; and with decreasing particle diameter and Reynolds number. A regression
equation closely fitted the obtained numerical results for different conditions. The equation is useful for directly calculating
the electrostatic loss of nanoparticles in the corona needle charger during particle-charging process. 相似文献
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To achieve reliable and autonomous regolith sampling from asteroids in space, the authors have developed a new sampling system that utilizes electrostatic force. This system consists of electrostatic capture and transport subsystems. Regolith particles on an asteroid are captured through parallel screen electrodes activated by the application of an alternating high voltage. The captured particles are then transported to a collection capsule from side to side basically along the electric flux lines in a zigzag path where an alternating electrostatic field is applied. It has been demonstrated that glass and sand particles can be transported in the horizontal direction that imitates micro-gravity on asteroids. The transport rate was increased by applying a high voltage of appropriate frequency. The demonstrated transport rate was approximately 3 g/min. The configuration of the path was improved to increase the transport performance. Numerical calculation using the discrete element method predicted that the transport of particles is successful if the gravity is less than 0.02-G. The process of sampling particles on asteroids will be easier than that on the Earth, because gravity is extremely low on small asteroids, particles are assumed to be highly charged because of cosmic rays, no air drag is exerted on the particles, and high voltage can be applied in vacuum where no gas discharge occurs. 相似文献
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H. Kawamoto 《Journal of Electrostatics》2009,67(6):850-861
Because manipulation of single particles is of great importance in the fields of electronics and biology, the author has been investigating an electrostatic manipulation system. The manipulation probe consisted of dipole pin electrodes. When voltage was applied between the electrodes, the dielectrophoresis and coulombic force generated in the non-uniform electrostatic field was applied to the particle near the tip of the electrode. The particle was captured by the application of voltage and then it is released from the probe by turning off the voltage application. It was possible to manipulate not only insulative but also conductive particles. However, if a particle was charged, the Coulomb adhesion force prevented the release of the particle even when the voltage application was turned off. This condition was generally observed for small particles. Asymmetric and coaxial electrode systems were developed so that the release of the attached particle was independent of the position of the probe. Instead of turning off the voltage application, high voltage was applied to the electrodes to blow off the particle by the ionic wind generated in a corona discharge field, and the applicability of this system was demonstrated. Further, a vibration separator was developed. A three-dimensional field calculation was conducted to calculate the dielectrophoretic force by using the finite difference method and the calculated force was compared to the measured force. It was deduced that the predominant force for the particle adhesion was not dielectrophoresis but Coulomb force generated due to triboelectrification. 相似文献