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25 June 1993, Volume 13 Issue 03 Previous Issue    Next Issue

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NUMERICAL ANALYSIS OF PARTITION CAPACITANCE OF LONG MULTICORE H-CABLE Tang Zequn Liu Jianxin (Beijing Institute of Spacecraft Systems Engineering) 1993, 13 (03):  .  Abstract ( 1924 )   Save This paper calculates the partition capacitance of a longrnulticore H-cable and the partition capacitance of long parallel wiresabove the ground using moment methods. Related Articles | Metrics

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DESIGN AND ANALYSIS OF MULTI-STEP AMPLITUDE QUANTIZATION WEIGHTED 2-D SOLID-STATE ACTIVE PHASED ARRAY ANTENNAS Gao Tie Li Jianxin (Nanjing Research Institute of Electronics Technology) 1993, 13 (03):  .  Abstract ( 1575 )   Save In this paper,an aperture designing technique of multi—stepamplitude quantization for two—dimensional solid—state active phasedarrays to transmit low sidelobe is described.It is shown that this methodis effective to reduce the Peak sidelobe level of solid-state active Phasedarrays and can be applied to the arbitrary complex aperture antennas.In addition,gain loss and sidelobe degradation due to random amplitudeand phase errors and element(or T/R module)failure are investigated. Related Articles | Metrics

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SYSTEM FREQUENCE FLOW AND SPECIFICATIONS ANALYSIS FOR SPACEBORNE RADAR ALTIMETER Liu Jinglin (Xi'an Institute of Space Radio Technology) 1993, 13 (03):  .  Abstract ( 1617 )   Save Of the active microwave remote sensors for ocean observa-tion,the Fine Radar Altimeter is a satellite payload of high benefitand vast use,which has been confirmed on a global scale.Seasat RadarAltimeter is a critical tool for all-weather observation.While the geoidis finely determined,the results are very useful for the research anddevelopment of oceanography,geodetic topograph,ocean deep survey,morning and evening tides,ice,wind,wave etc.In this paper,theresearch is only on that for the frequence flow and the specificationsanalysis of main parts and subsystems of Seasat Radar Altimeter system. Related Articles | Metrics

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RESEARCH ON RADIATION FIELD OF ARBITRARILY ORIENTED LINEAR ANTENNA OVER CONDUCTING ROTATIONARY BODY Wang Jueqi (Beijing Institute of Spacecraft System Engineering) 1993, 13 (03):  .  Abstract ( 1464 )   Save Radiation field of arbitrarily oriented linear antenna overa conducting rotationary smooth body is researched.By utilizing methodsof moment and Fourier analysis,the expressions for harmonic compo-nents of induced currents on the conducting surface are given,and thenthe radiation field may be evaluated.As an example,the radiation fieldof an oblique Hertz dipole over a sphere is calculated and compared withthat obtained by classical method.Two results are identical. Related Articles | Metrics

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A RESEARCH ON FRICTION COEFFICIENTS OF HIGH-SPEED RADIAL BALL BEARINGS IN ROCKET GYROSCOPES Xu Dawei (Shanghai Machinery Technology Institute) Gu Peizhi (Shanghai Jiao Tong University) 1993, 13 (03):  .  Abstract ( 1600 )   Save On the basis of analysing and studying systematically theforces acting on balls and inner rings(or outer rings)of high speedradial ball bearings in rocket gyroscopes(are called“high-speed ballbearings”for short)by means of the rolling bearing theory,the rollingtheory in tribology and the principles in elasticity mechanics,a group of formulas for calculating friction coefficients of high-speed ball bea-rings has been advanced in this paper.The analytical relationshipsexpressed by the formulas derived indicate clearly that the frictioncoefficient of a high speed ball bearing is related to not only the bore,outer diameter,sliding friction coefficient between ball and inner ring(or outer ring),ball diameter,ball number,but also the rotativespeed and equivalent dynamical load of the high speed ball bearing. Related Articles | Metrics

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FIXED TOLERANCE SYNTHESIS TECHNIQUE FOR ARRAY ANTENNA RADIATION PATTERN Qi Yihong (State Key Laboratory of Millimeter Waves,Southeast University,Nanjing) Jiao Yongchang (Xidian University,Xi'an) Chen Jianrong(Xi'an Institute of Space Radio Technology) 1993, 13 (03):  .  Abstract ( 1711 )   Save In this paper we are concerned with the synthesis techni-ques of array antenna radiation pattern where the optimization parametersare subject to fixed tolerance.The mathematic models for array antennaradiation pattern optimization are given,the discrete method for solvingthe worst-case problem is presented and the physics models for arbitrarytolerance distribution of array elements are initiated,finally,the imp-roved regular polyhedron method is employed to optimize the broadsidearray in which the excitation amplitude have tolerance.In the presentwork the deviations of th actual performance from its desired one areminimized if the design parameters deviate from its nominal values. Related Articles | Metrics

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MONITORING EARTHQUAKE BY USING GPS Li Yanxin Wang Min (First Land Deformation Monitoring Center,State Seismological Bureau,Tianjing) 1993, 13 (03):  .  Abstract ( 1920 )   Save Space positioning techniques by using GPS can give high re-lative positioning precision(10~(-6)～10~(-8)),and is a new method to monitorcrustal movement and forecast the earthquake.North China is an activeseismic region where earthquake frequency and its intensity are high.Byusing GPS,an earthquake monitoring network is established in NorthChina.Based on meticulous observation,optimum design and close adjust-ment,a first group of results with high precision are obtained.Establi-shing of GPS network in North China will form an important scientificbasis forecasting of heavy earthquake and studing of the earth. Related Articles | Metrics

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THE DESIGN OF A ALUMINIUM HONEYCOMB CORE DRAWING MACHINE Li Liancheng (Beijing Spacecraft) 1993, 13 (03):  .  Abstract ( 1453 )   Save This paper studies the tensile force for the extention ofaluminium honeycomb core which is used in the sandwich structures ofsatellites.By the introduction of the design of a aluminium honeycombcore drawing machine,the drive theory,the selection of basic Parametersand the analysis of main structures are described briefly. Related Articles | Metrics

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ANALYSIS OF IMPACT ATTENUATION DEVICE PERFORMANCE AND STUDY OF CONTROL METHOD Tong Xudong (Beijing Institute of Space Machine and Electricity) 1993, 13 (03):  .  Abstract ( 1495 )   Save The impact attenuation technology is more and more widelyused in recovery system of spacecraft.The two kinds of retrorocketthrust mode applied in impact attenuation process are compared in thispaper,and the factors are analysed which influence the final perfor-mances of the system in impact attenuating process.The changes of systeminitial and environment conditions are regarded as the maximum inf-luence factor,so a pragmatic control method is put forward to solve thisproblem.By applying this method the influence of the changes of theinitial and environment conditions on the performances of impact attenu-ation device can be eliminated ultimately. Related Articles | Metrics