Apply the Hybrid Method of FDTD/MoM to Calculate the Radiation from the Aperture

This paper presents a hybrid method of the Finite-Difference Time-Domain(FDTD) and the method of moment(MoM) to compute the radiation from the aperture.The FDTD is a commonly used electromagnetic simulation way.It can solve the question with complex dielectric,but it is difficult(even cannot) for FDTD to calculate the far field because of large compute time and computer memory.So the authors can make use of the FDTD to get a large number of near electric field intensity,and then use the MoM,which based on electric field integral equation to compute the far field.Using this procedure,the authors solve the radiation of the box with apertures on one or more sides and reduced the compute time and the computer memory.     

Nominal electric field calculation at the ground level of UHV DC transmission lines based on radial basis function method

Nominal electric field at ground level is one of the important factors for the design of transmission lines. FEM meets two big challenges in electromagnetic field computation. One comes from the mesh generation, which is a big difficulty especially in complex geometry. The other is the long time calculation. So the radial basis function method is introduced to calculate the nominal electric field at the ground level of UHVDC transmission lines. Not only the definition and ideas, but also the detailed implementation procedure of radial basis function method are presented. Computer programs are developed to simulate the model and the influences of conductor configuration on nominal electric field intensity are analyzed. Examples of calculation show that the results are accorded with those available literatures, and agreed satisfactorily with analytic solutions of the coaxial cable model. The height of the polar lines and conductor inter-spacing has a remarkable influence on ground nominal electric field intensity while the sub-conductor radius and number of sub-conductors have little influence.     

高压电晕电场处理紫花苜蓿的生物效应

为研究高压电晕电场生物效应物理机制,非均匀电场和电晕放电产生等离子体注入2种因素对种子的影响,利用频率为50 Hz,极距为4 cm,电压为0(ck)、4 kV、8 kV、12 kV、16 kV、19 kV的交流高压针-板电晕电场处理紫花苜蓿种子,通过1 mm厚的聚丙烯培养皿盖电介质阻挡和不加培养皿盖2组放电处理。培养后检测不同参数的高压电晕电场处理对紫花苜蓿种子生长的影响。结果表明:高压电晕电场处理紫花苜蓿种子时,无论是否有培养皿盖阻挡放电,均可改善紫花苜蓿种子的亲水性,使种子沉入培养皿底部,无培养皿盖阻挡放电组改善程度更大,除8 kV加盖阻挡组种子的吸水率比对照有所下降外,其余各组吸水率均上升。有无培养皿盖阻挡放电对紫花苜蓿种子的发芽势和发芽率有截然相反的影响,整个变化趋势呈非单调震荡型曲线,经培养皿盖阻挡放电后,可以非常有效的减小离子风对种子的物理刻蚀程度,同时降低紫花苜蓿种子接受的场强,并使紫花苜蓿种子接受的辐射电场更趋均匀。     

Surface Charge Distribution and Tip Electric Field about Carbon Nanotubes

Carbon nanotubes(CNTs) have some special physic properties which may own important technical values. We studied the electric characteristics of metallic carbon nanotubes including potential distribution, surface charge distribution and tip electric field based on electromagnetic theory. Our results show that the relative values of tip charge densities of short CNTs are bigger and so are the absolute values for long CNTs. We also find the electric field at the tips of metallic nanotubes is much bigger than external electric field. This is helpful for exploring theoretical problems about CNTs' field emission.     

Nitrogen reduction stimulated by a three-dimensional electrochemical-biofilm reactor and its correlation with electric field

To realize automatic control, it is important to study the response of reactor to electric field. A three-dimensional biofilm eletrode reactor is developed and steadily operated to remove nitrogen. In the reactor, oxygen is produced on the anode and hydrogen is produced on the cathode of the three-dimensional electrode by electrolysis water. Microorganism in the reactor utilize oxygen and hydrogen adequately to remove nitrogen by nitrification-denitrification. To evaluate the correlation of electric field with the reactor, DO, pH and nitrogen removal efficiency are studied. Results show that when a electric field of 0.013 4 mA/cm 2 is applied to the system, the removal rate of NH +4-N, NO -3-N and TN is 90%, 70% and 70%, respectively. To assure the reactor run efficiently, the maximum of the intensity of electric field applied to the reactor is 0.0201 mA/cm 2. Within 0.0201 mA/cm 2, the system is in stable running status, while DO and pH is altered resulting from the intensity of electric field. With enhancing the intensity of electric field, the removal rate of NO -3 -N can be improved, although, the removal rate of NH +4-N is not elevated markedly. There is no accumulation of NO -2 -N within 0.0201 mA/cm 2.     

Spray Characteristics of a Two Phase Air water Nozzle for Indirect Evaporative Cooling

We present a two phase air water nozzle that can be applied to indirect evaporative cooling to improve the heat transfer efficiency of indirect evaporative coolers by improving the uniformity of the water film on the surface of the heat exchanger. The spray characteristics of a nozzle with a fan shaped orifice at various air and water pressure conditions was studied. The spray cone angle, the air water mass flow rate, and the relationship between the mass flow rate and the air water pressure ratio were obtained. The best air water pressure ratio and spray cone angle were also found.     

Effect of humidity and temperature on power electric field intensity

We measure power electric field intensity at a substation in southwestern P. R. China at various humidity levels and temperatures. Measurement data and a back propagation neural network are used to construct a model of electrical field intensity responses to fluctuations in humidity and ambient temperatures. The maximum error is 0.047 5. The results show that the power electric field intensity increases as humidity rises when the temperature is constant; when humidity is a constant, temperature changes do not affect the regularity of the electric field intensity in a consistent manner regularly.     

The

This paper describes a digitization detection method harmonic analysis method which is used for detecting the dielectric loss of the electric equipments.The principle of this method and its characteristics of hardware circuits are introduced also.The testing results in the lab and the field show that this method can measure the dielectric loss rather stably and accurately.     

电场处理对油葵幼苗抗旱能力的影响

用不同场强的电场处理不同油葵品种的种子，发现电场处理组的油葵幼苗，在水分胁迫下体内超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性下降程度均小于未处理组，膜脂过氧化产物(丙二醛)的含量低于未处理组，二叶一心期的水分自然饱和亏值低于未处理组，说明幼叶保水力增强；因此认为静电场处理提高了油葵幼苗期的抗(耐)旱性。实验还发现，不同电场强度对不同的油葵品种的影响效果不同。     

Detecting System of the Dielectric Loss in Capacitive Equipment Based on Virtual Instruments

A digital detecting system of the dielectric loss in the capacitive equipment is introduced based on virtual instruments.This system can real-time collect,analyze,process and storage electrical signals with National Instruments' program LabVIEW and ADLINK,s DAQ board.Through the simulation test in lab and the real test in electric substation,it is shown that this system has high accuracy on testing the dielectric loss in the capacitive equipment,the real test data is stable and the relative error of real dielectric loss is less than 5%.It is to say that this system can meet the requirement of the real on-line monitoring.     

蓝莓塑料箱式气调保鲜技术研究

采用4种调气嘴调控的塑料气调箱进行箱内气体成分变化规律及贮藏蓝莓的保鲜效果试验,结果表明：在冷藏（0±0．5）℃条件下,装有蓝莓果实的4种调气嘴调控的塑料气调箱内有相似的气体变化规律,即CO2含量不断上升,O2含量不断下降,均在22天时出现CO2明显增加现象。蓝莓贮藏75天结果表明．各处理气调箱内的气体环境均可显著地控制果实腐烂率与软果率．其中调气嘴B处理气调箱内的蓝莓果实保鲜效果最好．可保持较高的可溶性固形物含量。好果率达到91．23％。塑料箱式气调保鲜技术贮藏蓝莓适宜的气体浓度为：CO2 10％～12％,O2 6％～9％。应用该技术贮藏蓝莓可比现有其它贮藏方法延长保鲜期30～40天．     

Exact Calculation for Measuring Electric Intensity with Ellipsoid Gauge

Based upon the anisotropy of electric polarization,the nonolinear oscillation equation of the ellipsoid in electric field is constructed by considering the rotative moment between electric field and the induced dipole moment on metallic ellipsoid of field intensity gauge. The oscillation period relative to the amplitude and electric intensity is calculated.An expression of exact computation to measure the electric field intensity is achieved.The impact of the amplitude parameter upon the experiment calculation is analyzed and the method to determine the amplitude is contributed.A contrast to the computed resuls by means of linear oscillation is undertaken to show the raising effect to the calculation precision by considering nonlinearity in oscillation.     

Study of Lightning Impulse Breakdown Voltage Correction of PositiveRod-Plate Short Air Gaps on Altitude

The air pressure of the high altitude condition in the artificial climate chamber is simulated, and the laboratory investigation of positive rod plate lightning impulse discharge performance were carried out on the short air gaps of 200 mm, 300 mm and 450 mm according to the test method demanded in IEC 60.1. Based the tested results, it is put forward that the positive lightning impulse breakdown voltage of a short air gap at the air pressure of the high altitude district is a power function of the air pressure with a special index less than 1, which indicates that the effect of the air pressure on the breakdown voltage decreases by 8.7% with the increase of the altitude by 1 kilometer. According to the theoretical analysis, it is proposed that the air pressure suggests the comprehensive changes of the basic atmospheric parameters of the temperature, the reltive air density and the absolute humidity, thus it could be used as the characteristic variable which expresses the effect of the absolute humidity, thus it could be used as the characteristic variable which expresses the effect of the atmospheric condition on the breakdown voltage of an air gap.     

种子分选电场对发芽指标的影响

选用玉米、黄豆、小麦和棉花种子,应用高压静电场对其进行处理,测定了处理组与对照组的发芽指标参数,探讨了静电场处理农作物种子对种子发芽指标的影响。对结果进行了回归分析,得出回归方程,并依此进行预报,找出对种子处理的时间和电场强度的较佳取值组合。     

多技术集成模块对景观配置及群落空气质量的优化空间探讨

摘要：为了探讨景观配置及群落空气质量的优化空间,本研究采用多技术集成模块,结合景观取样、评判、优化方法,研究了多集模块对园林景观配置及群落空气质量优化空间。结果表明,化控处理(HGa、HIAA、RCC、RP)与对照间△株高、△地径有极显著差异,供试品种的促进率和抑制率均在田间试验的最佳比率范围内;Blocknto区块优化后提高了植物种类、季相色彩以及空间层次的丰富度;优化前后的Blocknto区块存在显著差异,优化使其在综合评判结果上提升了2个等级。优化后Blocknto区块空气中各污染物指标,均有一定程度的下降,其中PM2.5、PM10、SO2、AQI等指标存在极显著差异,CO、NO2等指标存在显著差异。     

山西中南部一次暴雪过程诊断分析

为了进一步分析山西中南部暴雪过程的形成原因,笔者利用常规和非常规气象观测与监测资料,针对2014年2月4—6日山西中南部暴雪天气过程,从高空、地面天气形势、中低层流型配置、雷达回波及物理量场的空间垂直剖面进行综合分析。结果显示：该次暴雪过程以500hPa西风槽、南支槽相继影响、地面倒槽前部东南气流的控制为背景。500hPa西风槽,700hPa西南急流与横切,850hPa东南急流为该次暴雪的中尺度有利配置。回波强度在15~30dBz,属连续均匀的稳定性降雪回波。物理量场的相对湿度在200hPa以下为大于80%的湿空气柱、对流层为一致的上升运动、高层辐散与低层辐合构成了有利于强降雪的环境条件。     

2011.7山西区域性暴雨天气过程诊断分析

为了进一步研究山西区域性暴雨天气过程的主要成因,利用常规和非常规气象观测与监测资料,对2011年7月1—3日山西区域性暴雨天气,从大尺度环流背景、中低层影响系统、红外卫星云图、不稳定能量及物理量场的空间垂直剖面进行综合分析。结果表明：该次暴雨发生在东高西低副高影响的环流背景下,中低层切变为暴雨主要影响系统,强烈的上升运动、低层辐合高层辐散的流场配置为暴雨提供了有利的动力条件,涡度场与高低空系统的时空分布变化相一致,ki指数≥32℃的高能区、si＜0℃的不稳定区域在降水时段始终与中低层切变系统的位相一致,促进了持续性强降水的产生。     

高压电场处理番茄果实的电磁学分析

以番茄果实为试材,在对真空和空气中的平行板电场进行电磁学分析基础上,研究了下极板摆放果实时平行板电场,中间插入金属板并摆放果实时平行板电场,中间插入电介质并摆放果实时平行板电场。结果表明,在极板间添加番茄后,由于增大了极板组成的电容器电容,造成极板电荷增大,空气层场强增大,番茄层场强相比于E_0有所减少;当电容器下极板摆满一层果实,并且在平板中间插入金属板,其上也摆满果实时,所组成的电容器等效电容C有所增大,极板上富集电荷Q有所增大,空气层场强相比于E_0有所增大,但E_f相比于E_0会随h及ε_h的不同产生变化;当电容器下极板摆满一层果实,并且在平板中间插入一层电介质,其上也摆满果实时,所组成的电容器等效电容C有所增大,极板上富集电荷Q有所增大,空气层场强相比于E_0有所增大,但E_f及E_h相比于E_0会随h及ε_h的不同产生变化。     

脉冲电场预处理对马铃薯微波干燥特性的影响

设计了2因素(脉冲频率和电场强度)3水平的正交试验,以干燥时间为试验指标,探索脉冲电场预处理对马铃薯微波干燥特性的影响。通过直接分析和极差分析,并与未处理样品进行比较,结果表明脉冲频率比电场强度对马铃薯微波干燥时间的影响略大;其中,最优组合(40Hz,1.5kV/cm)的脉冲电场预处理可使马铃薯微波干燥的时间减少23%。     

Mine transient electromagnetic field multiples phenomenon

In order to accurately calculate the magnetic field parameters of mine transient electromagnetic field based on the former research theory of transient electromagnetic field full-space and half-space combined with transient electromagnetic space applications in mines this article studies the relationship of transient electromagnetic field intensity and half-space transient electromagnetic field and proposes the multiple phenomenon of transient electromagnetic. Research results show that full-space transient electromagnetic field intensity and half-space transient electromagnetic field intensity has multiple phenomenon. They have 2 times relationship in the early stage and have 2.5 times relationship in the late stage. Similarly mine transient electromagnetic field intensity electric field intensity and apparent resistivity calculations also have multiple relationships. Putting forward the multiple phenomenon has important reference value in theory and practice for researching the mine transient electromagnetic field.