Mechanism and experimental analysis on high-frequency electromagnetic anti-fouling for industrial circulating water

In industrial cycling cooling water system, the dirt of heat exchanger causes enormous economic losses, and the traditional anti-scaling method has disadvantages, such as secondary pollution, poor results and high cost, etc. While the anti-scaling of electromagnetic field is convenient, pollution-free and low cost. These are advantages that other methods don’t have. A high-frequency electromagnetic device with DDS and amplifier technology for different water is designed, and its output is single frequency and sweep of the square wave signal within the scope of 0~1 MHz. A dynamic circulating water system is set up in laboratory to simulate industrial water cycling system. The research results show that external high-frequency electromagnetic field slows down the crystallization rate. Part of original calcite comes into aragonite. In addition, the effect of anti-scaling is effected by the concentration and output frequency, while the higher output frequency doesn’t always obtain better result, and the concentration of calcium should not be more than 5 mmol/L.     

Modeling and simulation of the conducted electromagnetic interference for permanent magnet direct current motors

A simulation model for evaluation of conducted electromagnetic interference(EMI) is developed based on analysis of the mechanism giving rise to conducted EMI. The simulation model includes high frequency effects associated with stray distributed parameter     

特定磁波对作物某些生理生化特性的影响

报道特定电磁波变辐射器（TDP）辐照各种大田作物及蔬菜作物,包括小麦、水稻、玉米、高粱、番茄、萝卜、碗豆等的种子和萌发种子后对作物某些生理生化特性的影响。结果指出,TDP辐照能显著促进淀粉酶、过氧化物酶、SOD的活力,增加ATP含量、超弱发光强度、种子放热量,提高P/O值和蛋白质含成强度。     

温室大棚采暖设备智能控制关键技术的研究

针对目前设施农业生产中采暖设备在温升过程中存在的污染大、能耗大、安全隐患大、可靠性差等问题,研发一种新型的设施农业温室采暖智能控制系统。将控制终端技术、信息和通信技术、执行机构设计与现有设施农业中相关技术模式进行整合,在不影响生产效率的前提下降低设施农业生产中的污染,提高温升过程中的热转化率和温升速度,同时满足长时间、高可靠性的运行要求,精确控温,从而达到绿色、节能、环保的目的。     

电磁场辅助冻结-解冻技术研究进展

介绍了电场、磁场辅助冻结-解冻技术的研究成果,对其作用机理进行了分析,并介绍了电磁场辅助冻结-解冻设备研发现状,展望了电磁场辅助冻结-解冻技术的应用前景,以期为食品冷冻保鲜提供参考借鉴。     

The Application of Complementary Variational Principles in Sinusiodal Electromagnetic Field

Considering the need in practical applications the authors extend thecomplementary variational principles from single-medium to multi-medium. The equivalencebetween variational problems and multi-region boundary value problems is proved,Utilizing theextended functional and complementary functional,we construct the complementary variationalproblem in a sinusoidal el ectromagnetic field.Several special forms in computating differentsinusoidal electromagnetic field problems are given.     

The Calculation of Electromagnetic Fields in Sapce Around Lightning Path

This thesis studies mathematical model for calculating electromagnetic fields in space around lightning path.The calculating method which can more exactly calculate the distribution of electrocmagnetic fields in space around lightning path is developed.The results are consistent with results of refereces and simulating test.It supplies references for interference protection desigh of electronics such as computers ect.     

The Application of Relevant Homology in the Unified Representation of Electromagnetic Potentials and Gauge Transformation

Electromagnetic potentials and gauge transformation are derived for non-cloSedexterior differential forms with the help of relevant homology.Since de Rham ccahomology is sure-ly a relavant homology. potentials for both closed and non-closed forms and the gauge transforma-tion ean be unified in terms of relavent homology.     

The Simulating and Actual Measuring Calculation of the Inverse Problem of Circular Low Frequency Electric Current Field

The inverse problem of circular low frequence electric current field is calculated using simulated and actually measured data by modified iterative equipotential line algorithm.     

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。     

Maxwell''s Equations and Differential Forms of Electromagnetic Quantities

The geometrical properties of electromagnetic quantities are studied and the dif-ferential forms are introduced. It is shown that the differential forms are more suitable for describingelectromagnetic quantities.Finally , Maxwell's equations are presented in terms of differentialforms.     

Design of Alternating Current Excitation Generators

In this paper,the design feature of Alternating Current Excitation Generators(ACEG) is discussed.The electromagnetic design program of ACEG is established for engineering practice.A PC based software for design has been finished.A sample ACEG is calculated with the software.     

B-SPLINE FINITE ELEMENT METHOD IN GENERAL 2-D FIELD REGIONS

A B-spline finite etement method for solving general 2-D electromagnetic field problems is established. The B-spline bases for a general field region are constructed using the Bspline interpolation functions defined on a rectangle which contains the region. The Dirichlet boundary condition is dealt with by means of the generalized variational principle. Two numerical examples are given that show the characteristics and practical value of the method.     

Application Of Virtual Instrumentation in Radio Measuring System

Radio administration department permits station's building and distributes frequency used by measurement in radio electromagnetic environment. In order to improve the efficiency and accuracy of testing, the automatic measuring system software based on virtual instrumentation technology(VISA and SCPI) has developed at the VB platform, which changes the phase of outputting data just by printing spectrum chart .The system realizes functions of data sampling, transffering and processing in HP E7405A EMC analyzer. It also can establish database files for saving, inquirring, data shareing, exchanging and processing. The spectrum chart of mearsurment result is the same as that of result by manual work.     

Energy delivery model for implanted devices

FEMlab3.3(Finite Element Model Lab) is used to develop an energy delivery model for implanted devices. We designed three different shape electrodes made of Ag to enhance current transmitting efficiency. Several voltages were used for pursuing perfect goal. With the body safety current, we can get the results with a current transmitting efficiency of 20% and the energy delivery efficiency of 4%~9%. It is clear that the high energy delivery efficiency can be obtained and the results provide references for further study of energy delivery through body conduction.     

Finite element modeling and multi-software co-simulation in automobile EMC prediction

For general software in the limitation of large and complex structures’ modeling, this article proposes a multi-software co-simulation technology. Hypermesh is a pre-processing software which can high-quality import and triangular CAD-models, taking advantage of this, the CAD-model of the car is meshed in Hypermesh. Using Matlab,the node coordinates data of each component’s elements are extracted from the grid data file outputted by Hypermesh, and are exported in the form of text file for Hfss to read.VBS program is used to build the finite element model, which is written in Matlab, then runs in Hfss to read the node coordinates data and form the initial triangular-mesh model of the Automobile. Considering only the interference of the ignition system power line’s common-mode current we simulated and analyzed the electric field distribution inside and outside of the automobile.This modeling method has a strong commonality ,and is a good reference for automobile EMC simulation modeling.     

GIS Partial Discharge Signal and Its Internal Sensor Detection

Partial discharge electromagnetic waves in GIS propagate is not only in the transverse electric and magnetic(TEM)mode, but also in transverse electric(TE) and transverse magnetic(TM)mode. The paper deduces out the mathematic expressions transient field excited by PD in GIS anywhere by using dyadic Green function theory. The contributions of TEM mode and all high order modes in the detecting frequency scope should be taken into consideration when calculating the electric field excited by PD in GIS. In simulative GIS laboratory, the designed inner couplers are superior to other outer sensors in detection of partial discharge. Inner couplers for the GIS model are developed and their frequency responses are analyzed in antenna model. At last the PD pulses excited by man-made defect are detected by inner couplers using high parameters oscilloscope.     

电磁辐射引起的表观遗传效应研究进展

电磁场是关乎人类生存的重要环境要素,研究发现电磁场除了引起生物基因突变外,还具有广泛的表观遗传效应,为了引起人们对电磁环境的重视,进一步促进对电磁生物效应的研究,归纳了前人对动、植物所做的电磁辐射引起的表观遗传效应研究,重点分析了γ射线、紫外线、微波辐射及无线电波在植物和动物学上的表观遗传效应研究进展,并提出一些可行的研究方向。     

高频电磁波水分测量精度影响因素的研究

在25℃±1℃的空调环境下,用含水率约10%的棉花秆为测量对象进行试验分析,对比物料堆放密度、料层厚度、测量距离与高频电磁波水分测量精度的关系。试验结果表明,测量距离对测量精度的影响最大,测量距离相差20mm,反射电磁波强度相差450%以上,而对堆放密度的影响约为16%。     

汽轮发电机稳态负序工况仿真模型及其对负序损耗计算结果的影响

稳态负序能力是大型汽轮发电机安全可靠运行的重要技术指标之一,而稳态负序损耗的准确计算是确定稳态负序能力的关键和基础。介绍了模拟发电机稳态负序运行工况的传统模型,针对其不足提出了一种新的不对称负载模型,并对2种模型所反映的物理机理和优缺点进行了对比分析。在此基础上,以一台1 550 MW的大型4极核能汽轮发电机为例,采用场路耦合的二维非线性时步有限元方法,结合2种仿真模型对其稳态负序损耗分别进行了计算,并对计算结果进行了详细分析。结果表明：相对于传统的负序模型,笔者提出的不对称负载模型充分考虑了磁饱和与转子附加损耗的影响,计算出的稳态负序损耗更接近实际情况,为准确考核大型汽轮发电机的稳态负序能力奠定了基础。