Abstract:The principle of frequency discrimination(FD) by digital transversal filter is discussed. A detailed analysis of the FD method by autocorrelation and auto-convolution is given and the slope and bandwidth of the characteristics of FD is obtained. In addition，the curves ∑I～ωand⊿Q～ω are computed and given in this article. This FD method can be used for AFC of the coherent-on-receive system.

Abstract:When a vehicle reenters the atmosphere，the communication will be discontinued. A lot of methods have been proposed to solve this problem. Some chinese and foreign scholars suggest methods of reductions of local electron density with applied electric field. In this paper，through synthesizing related theoretical and experimental results，the author finds that it is impracticable to reduce the electron density in the plasma sheath with applied electric field.

Abstract:Applying basic magneto fluid dynamic theory，the author analyzes the model f1owing in plasma sheath under the combined action of magnetic and electric field. Preliminary analysis shows that the density of the electronic number in parts of the plasma sheath is expected to be remarkably reduced if only electrodes are appropriately placed and applied electric and magnetic fields are proper1y selected.

Abstract:According to incomplete statistics，85% of existing rocket-missile weapon systems either in use or in the design stage are powered by a solid propellant，therefore，studies for improving computing precision and speed in determining the natural vibration characteristics of solid propellant rockets are of practical engineering worth. On the basis of the results of solid propellant tests and actual measurement on dynamic characteristics of solid propellant rockets in our university and in the light of theoritical calculations made by the authors of this paper，we put forward a proposal for improving computer precision and speed，which includes assumptions and selection of vibration computational theory.

Abstract:This article makes use of modulation technic of laser speckle to realize differentiation of the image so as to increase the detail and contour of the image. This kind of technic has many advantages，for example，it has a large field of vision，it is easy to master and by using it，we can get a good result. In achieving differentiation of the image，the article tells us how to use the methods of exposure with different exposure time interval for many times from theory and by giving some results of the experiment.

Abstract:The calibration curve of the manganin stress gauge in the range of 12kb--420kb has been determined experimentally in the paper. The two load techniques of gas-gun and chemical explosion are used in the experiment. The manganin stress gauge is encapsulated by heating and pressing with polytetra-fluoroethylene(PTFE) as the dielectric layer and fluoroethylene propylene (FEP) as the bonding agent.

Abstract:In this paper is discussed invariance of initial conditions for N-th order linear differential equations with constant coefficients，and a few instances are cited in illustration of its applications.

Abstract:This paper presents before the readers two important features of singlecrystal electron diffraction patterns in the cubic system. 1. In cubic system，whatever crystal electron diffraction pattern it is，you can find the rectangular spotty arrangement with or without center. 2. There is a simple definite mathematical relationship between the adjacent sides of the rectangle. Applying these two features to designate diffraction patterns will be much simpler than the conventional method.

Abstract:Polycarlosilane (PC)，the precursor of SiC filer，was preparod by heating polydimethysilane in the presenoe of polyborodiphenylsiloxne (python) as catalyst. The properties of polydimethylsilane，polycarbosilane and polyborodiphenylsiloxane have been investigated by IR spectra，chemical analyses，thermal analyses and pyrolysis gas chromatograph. The suitable reaction conditions were found tentatively. The results showed that the properties of the precursor depended on reaction tempesature，additive amount of polyborodiphenylsiloxane and reaction period of polycarbosilane synthetized. Silion carbide fiber was made by melt-spinning the polycarbosilane，making the precursor fiber infusible by heating in air to about 200℃ and finally heating under nitrogen to 1250℃.

Abstract:This article looks forward to the development of the ECCM techniques for radar from the point of view of modern ECM techniques. Anti-jamming，anti-reconnaissance，anti-ARM and anti-stealth are approached. It is suggested that the overall ECCM capability of the radar network must be properly organized on the bases of the capability and potentiality of ECCM of every radar station.

Abstract:The main aspects of the role of modern scientific methods in the research work are the entirety of research thought，the synthesis of research methods，the modelization of research means，the scientific organization of management and the optimization of overall situation，and in the military command are the moulding of mode of operations，the autamation of command system，the modernization of logistics and the scientific military forecast.