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25 December 1994, Volume 14 Issue 06 Previous Issue    Next Issue

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MEASUREMENT OF THERMAL RADIATION PROPERTIES FOR COMPOSITE OPTICAL SOLAR REFLECTOR Hua Chengsheng(Beijing Institute of SPacecraft System Engineering,Beijing 100086) 1994, 14 (06):  .  Abstract ( 1832 )   Save The measurement of the solar absorptance as and the hemispherical emittance AH were performed by the caloric method for opticalsolar reflector(OSR)that will be applied on the comnlunicationbroadcasting satellites.In order to calculate the temperature distribution of thesatellites correctly,the thermal radiation properties of the compositeOSR samples were measured.At the same time the solar absorptance of aOSR sheet was measured by both the caloric method and the spectralmethod for comparison.The measured results and the difference betweenthem were analysed.The analyses indicate that the normal solar absorptance αs.of a OSR sheet should not be taken as a design parameter,otherwise a larger error will happen in temperature calculation. Related Articles | Metrics

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THE EXPERIMENTAL STUDIES UPON THE VIBRATION PROPERTY OF AXISYMMETRIC VISCOUS LIQUID BRIDGE UNDER MICROGRAVITY Waug Xianrong(Lanzhou Institute of Physics,Lanzhou 730000)J. Meseguer(ETSI Aeronauticos,28040-Madrid,SPAIN) 1994, 14 (06):  .  Abstract ( 1711 )   Save In this paper Plateau Tank Facility(PTF)is used to investigate experimentally the vibrati on properties of axisymmetric viscous liquid bridges under simulated microgravity enyironment.Experimental tests are undertaken circularly for different bridge slenderness,different bridge positions,different vibration frequences and different bond numbers.The changes of bridge interface vibration amplitude versus vibration frequence are recorded in detail.The analysis of these data and spectrograms show that:(1)Bridge resonance frequences are moving towards the lower value of frequence with the increasing of the bridge slenderness.(2)Experimental relati ons between them are inyerse ratio curve. Related Articles | Metrics

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STRUCTURE DESIGN OF LARGE ELECTRON BEAM WELDING MACHINE WITH HIGH OR LOW VACUUM Tan Zhixin;Xu Qijin;Guo Shenghou(Lanzhou Institute of Physics, Lanzhou 730000) 1994, 14 (06):  .  Abstract ( 1659 )   Save The large electron beam welding machine with high or low vacuum is a special equipment used to weld titaniun alloy fuel tanks and welding seam of gas bottles of satellites.On the basis of the advantages of vacuum electron beam welding machine from domestic and abroad and the new structure design of the equipment,it was successfully developed.This article mainly describes t he working principle,technique properties and the structure features. Related Articles | Metrics

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DETERMINATION OF NAVIGATION INFORMATION BY GPS(or INS)/EQUATIONS OF MOTION DURING AEROASSISTED ORBITAL TRANSFER Nan Ying;Chen Shilu(Northwestern Polytechnical University,Xi'an 710072) 1994, 14 (06):  .  Abstract ( 1708 )   Save Based on the norminal trajectory of aeroassisted orbital transfer,the paper gives a new navigation scheme for the space vehicle:Nayigation hardware/Equations of Motion(EM),GPS/EM,INS/EM are studied for the vehicle to determine the navigation information during aeroassisted orbital transfer.High supersonic aerodynamic calculation formulasare introduced to deduce the equations of filter and observation for the hybrid navigation system.The numerical results show that the navigation precision of GPS(or INS)/EM are much higher than that of single EM.GPS,or INS.The GPS(or INS)/EM has more redundance thlan the GPS(or INS). Related Articles | Metrics

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SIMULATION EVALUTION FOR SATELLITEBORNE IMAGE GEOMETRIC QUALITY Guo Zhaozeng;Zhou Fan (Beijing Institute of Sated lie Information Engineering,Beijing 100081) 1994, 14 (06):  .  Abstract ( 1587 )   Save simulation model of Satellite-Borne Image photograph is set up,two camera sideview methods,attitude motion,orbit motion,Earth rotation,map projection and so on are included in this model.Then,the Satellite-Borne Image geometric quality was analyzed and simulated by using a computer, a geometric correction method is presented in this paper.It is a valuable reference for satellite design. Related Articles | Metrics

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THE LIMITS OF QUEUEING THEORY AND THE ESSENCE OF QUEUEING SIMULATION Luo Lichun (China Electronic Equipment SystemEngineering Comp any,Beijing 100083) 1994, 14 (06):  .  Abstract ( 1909 )   Save ueueing is a very popular and very important phenomenon in engineering and society.The analysis and study of it will contribute to solve a lot of problems in comlllunicati on. computer.aerospace and ECM. The Queueing theory has go some imp ortant results in aboye mentioned fields.Queueing simulation cixn compensate Queueing theory for its limits.A new definition of queue system has been offered in the paper.Review and snalysis of the previous results of Queueing theory are given three limits of Queueing theory are presented, and that essence of queueing simulation is in fact a digital filtering is p ointed out. Related Articles | Metrics

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HEAT PRODUCTION AND DISSIPATION OF ASTRONAUTS DURING SPACE ACTIVITIES Pang Cheng;Gu Dingliang(Institute of Space Medico-Engineering, Beijing 100094)Yuan Xiugan(Beijing University of Aeronautics & Astronautics,Beijing 100083) 1994, 14 (06):  .  Abstract ( 1858 )   Save eat production and heat dissipati on of astronauts during space flight are important parameters for engineering design of life support system as well as for judgement of their work loads and arrangement of work-rest rule.In conjunction with our early experiences and current literature,this paper introduced three methods for estimation of astronallts'metabolic rate.The mr heat production both in vehicular and in extravehicular activities were summarized and the causes of metabolic variat cons comprehensively analyzed. Discussion is stressed on the factorsinfluencing heat exch ange of space garment in hypobaric envir onmentsin order to convert the garment flow rate(STP)obtained in ground experiments into the equivalent flow rate for removing the same heat fromthe garment at various altitudes. Related Articles | Metrics

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A STUDY ON FAULT TOLERANT CONTROL OF SPACE VEHICLE DURING LAUNCHING PROCESS Wang Zhongsheng;Zhang Wanren(Northwestern Polytechnical University,Xi'an 710072) 1994, 14 (06):  .  Abstract ( 2014 )   Save n this paper,a ne w design method of tolerant techniq ne and its fault control of a space vehicle has been put forward according to the failure features of a space vehicle during launching process.The paper lays emphasis on acquisition of the failure information, choice of the methods of detecti on and diagnosis, fault-tolerant scheme and its implement. Related Articles | Metrics

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THE CALCULATED METHOD OF THERMAL CONDUCTIVITY OF CARBON FIBRE COMPOSITES AT LOW TEMPERATURES Zhang Jianke(Lanzhou Institute of Physics,Lanzhou 73 0000) 1994, 14 (06):  .  Abstract ( 1577 )   Save he Law of heat transmission mechanism,thermal conductivity effecting factors and calculation method of CFRP(carbon fibrecomposite)at low temperature have been researched and discussed.Onthe basis of analysis and discussion,the calculation methods have been summarized and the calculated results have been compared with the measuredresults. Related Articles | Metrics

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ENERGY PARTICLE ENVIRONMENT ON LOW EARTH ORBIT AND ITS EFFECTS ON SPACECRAFT Chen Guozhen;Lin Guocheng(Beijing Institute of Spacecraft System Engineering,Beijing 100086) 1994, 14 (06):  .  Abstract ( 1751 )   Save The Energy Particle Environment on Low Earth Orbit which is one of the environments,that have an important influence on spacecraft is described and its harmful effects are summarized. Related Articles | Metrics