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Vanadium dioxide (VO2) is a typical representative of strongly correlated electronic systems, which undergoes a reversible transition from the insulator phase to metal phase, induced by a certain threshold for each of temperature, electric field, illumination and pressure. The crystal structure of VO2 will undergo a reversible transition from monoclinic structure to tetragonal rutile structure when the phase transition happens, which is considered as the microscopic mechanism of VO2 metal-insulator transition (MIT). The conductivity of VO2 can be increased by 2—5 orders of magnitude when the MIT is induced by electric field, which makes VO2 possess good application prospects in the fields of restructurable slot antenna, terahertz radiation, intelligent electromagnetic protection materials, etc. Therefore, the reversible metal-insulator phase transition in VO2, induced by electric field, has long been a research hotspot, which however, has been seldom reported. Firstly, in this paper, the changes of the crystal structure and energy band structure of VO2 during MIT are introduced briefly. The methods of regulating the phase transition are given, including temperature control, bandwidth and band-filling control. Then, the important discovery and research progress of VO2 MIT induced by electric field based on the research method, response time, critical threshold field and phase transition mechanism are summarized and reviewed comprehensively. The method of studying the VO2 phase transition relates to its structure, including planar structure, three-terminal gated ?eld effect switch and sandwiched layer structure. The sandwich layer structure is more suitable for investigating the MIT characteristics of VO2 in experimental stage because of its structural advantage of preparation and test. The response time of VO2 MIT can be completed in nanoseconds, of which the substantial parameter has been revealed by many reports, also including the excellent reversibility of VO2 MIT. The MIT critical threshold field of the VO2 film can be tuned by element doping, coexistence of multivalent vanadium oxides and multiple physical field synergism effectively. The MIT mechanism of VO2 induced by electric field has been proposed so far, which includes joule heating mechanism and pure electric field mechanism, and the latter is considered to be more likely to give a reasonable explanation. Finally, in the paper the current problems of the VO2 MIT research and the near-future development direction of the VO2 MIT materials are also pointed out.

In order to study the corona discharge on the sharp conductor structure, the relationship between conductor radius and corona was found by analysis of the three basic structures of corona discharge, and calculating the potential around the conductor in the three cases. Based on the three basic structures, the model of sharp conductor structure of corona discharge was established. Since of it, the threshold voltage of it could be easily calculated, which may provide supports for the further research on corona discharge on the sharp conductor structure.

Corona discharge signal from the high-voltage transmission line exhibits unique characteristics compared to other radiation signals, which include wide distribution of frequency, small signal amplitude and strong randomness. The properties of frequency distribution of corona discharge signal and noise were tested in the range of 0 MHz-1.5 GHz to obtain the most beneficial detecting band. Based on the characteristics and properties, a high-gain helical antenna with the center frequency of 250 MHz was designed, and the performance of the antenna was tested. The corona discharge signal from 550 kV extra-high-voltage power line at the distance of about 320 meters was successfully detected by the helical antenna. The results showed that this design achieves the expected requirements and have a good practical performance. The design of antenna may provide supports for the further research on remote detection system of corona discharge signal.

A computerized adiabatic calorimeter for heat capacity measurements in the temperature range 80–400 K has been constructed. The sample cell of the calorimeter, which is about 50 cm3 in internal volume, is equipped with a platinum resistance thermometer and surrounded by an adiabatic shield and a guard shield. Two sets of 6-junction chromel-copel thermocouples are mounted between the cell and the shields to indicate the temperature differences between them. The adiabatic conditions of the cell are automatically controlled by two sets of temperature controller. The reliability of the calorimeter was verified through heat capacity measurements on the standard reference material α-Al2O3. The results agreed well with those of the National Bureau of Standards (NBS): within 0.2% throughout the whole temperature region. The heat capacities of high-purity graphite and polystyrene were precisely measured in the interval 260–370 K by using the above-mentioned calorimeter. The results were tabulated and plo...

The ESD charge transfers from a charged insulator are investigated in this paper. Many factors including the electrode diameter, areas of charged insulator and the distance from the charged insulator which influence the charge transfers have been investigated. It has been found that the charge transfers are maximum when the diameter of the electrode is 20 mm, the areas of the insulator is about 200 cm/sup 2/ under the same potential. The relationship between maximum charge transfers and the potential of charged insulator has been found. The results show that the minimum potential of charged insulator which will ignite the flammable gases of minimum ignition energy of 0.2 mJ is about 35 kV.

The negative effect of spacecraft inside isolated conductor surface charging is more unobvious, causing more serious direct and potential harm. Considering the electrons and ions, the secondary electron emission, according to the kinetic theory of gases and combing the theory of particle in Maxwell velocity distribution function, calculate general expression in a plasma environment unbiased solid surface charging. Using the voltage general expression, we deduce the expression of energy and electric quantity, discuss the relationship between energy of isolated conductor's electrostatic field and surface as well as space environment in special environment, compare the energies of electrostatic field in different environments and different surfaces with electromagnetic pulse discharge damage of ground electronic components, and finally summarize the rules of area effect of isolated conductor's surface charging.

To investigate the mechanism of electrification from aero-engine jet and the electrification effect on the overall charging characteristics of vehicle, a simulation model of concentration of charged particles in aero-engine is build based on the equations of fluid motion. And concentration changes of various particles are simulated. To verify the simulation result, a special electrostatic induction sensor for detecting the electrification of engine jet is designed, according to the principle of the Faraday cup, to measure the dynamic potential when the turbofan engine starts, operates steadily, accelerates, decelerates and stops. The simulation and experimental results show that the aircraft is negatively charged by the electrification from aero-engine jet and the mechanism of electrification from aero-engine jet is described specifically. The research may provide a guidance to the further study on analyzing the overall charging characteristics of vehicle during the flight.

Spacecraft surface charging and discharging in a plasma environment are affected by many factors, and the charging time is an important factor to influence the discharging frequency. In this paper, considering microstructure and material parameters of the plasma characteristics, appling the principles of mechanics to each particle, and using statistical methods, the expression of isolated conductor ball surface charging potential time-domain is deduced. Using the general expression of voltage, we deduce the expression of the time domain of electrostatic charging quantity of isolated conducting sphere and the expression of the time domain of the electrostatic field energy. Taking low earth orbit and geosynchronous orbit for example, we discuss the potential of isolated conducting sphere, static load and the characteristics of the electrostatic field energy. The influences of space environment parameters and the size of the conducting sphere radius on surface charging are analyzed. The laws of the time domain of isolated conductor surface charging in plasma environment are summarized.

Within the plasma environment of spacecraft, the interaction between electrons and ions may cause surface charging and discharging and may degrade the performance of spacecraft. The charging potential is a key factor for discharging process. By considering the comprehensive effects of particle mass, temperature, density of plasma, secondary electrons and the velocity of unbiased solid, a general equation of surface charging potential of unbiased solid has been derived using Maxwell velocity distribution function. The expressions under some special and general conditions have been also analyzed. The surface charging and discharging properties are summarized under different plasma environment and motion states of unbiased solid.

When polyvinyl chloride (PVC) is irradiated by an ion beam, at medium doses of 150 keV Ar+ ions, the surface electrostatic properties of this polymer are dramatically changed. The triboelectrostatic charge can be decreased from 1.24 to 0.02 nC cm−2 or less and the electrostatic potential decreases from 800–1000 to 0–50 V. The charge time constant decreases from a few hours to less than 1 s and the surface resistivity drops by four orders of magnitude. New anti-static materials may be produced.