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25 December 1989, Volume 9 Issue 06 Previous Issue    Next Issue

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RADIO ASTRONOMY REJECT FILTER Wu Xuda (Xi-an Institute of Space Radio Technology) 1989, 9 (06):  1-6.  Abstract ( 2042 )   Save This paper presents a filter protecting the radio astronomicalfrequency band,which is a novel coaxial band-rejection filter in structure.The filter uses λ/4 coaxial cavities as resonater and round wire in squareouter conducter as transmission line.In designing of the filter by makinggood use of design technology of coaxial filters,the measured performanceof high attenuation in stopband and low insertion loss in passband issatisfactorily obtained. Related Articles | Metrics

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MOULD DESIGN FOR SUPERPLASTIC FORMING OF TITANIUM ALLOY Liu Zhixiong (Beijing Orient Scientific Instrument Factory) 1989, 9 (06):  7-15.  Abstract ( 1613 )   Save This paper describes the main technical problems of the moulddesign for superplastic forming of titanium alloys,such as different ways ofheat forming,mould materials,structure design,electric power calculation,electric heaters,heat insulators,gas sealing under high temperature andso on. Related Articles | Metrics

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DISCUSSION ON OPTIMAL ORBITAL TRANSFER OF THRUST-LIMITED MULTISTAGE SPACE VEHICLE Li Dayao 1989, 9 (06):  16-22.  Abstract ( 2179 )   Save Similar to rocket vehicle,space vehicle can be divided intosingle and multistage ones.A multistage space vehicle consists of several spacevehicles with engines(by series-mounting).This paper deals with the opti-mal orbital transfer for this class of space vehicle.The optimal orbital transfer of a thrust-limited multistage space vehiclebelongs essentially to a multistage optimal control problem.Using the solvingprinciple of a multistage optimal control problem,this paper discusses twokinds of the problems of the optimal transfer between two circular coplanerorbits for a thrust-limited two-stage space vehicle,gives the solving equationsand conditions of determining optimum thrust programs and optimum trans-fer orbit for the two kinds of problems.Especially,the conditions to besatisfied at the stage-to-stage separation moment are examined.The concept introduced in this paper is adaptable to the problems of opti-mal transfer between non-circular and non-coplaner orbits. Related Articles | Metrics

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SHAPED GREGORIAN FEEDS Jia Cunxi (TAIHUA Scientific Instrument Factory) 1989, 9 (06):  23-30.  Abstract ( 1897 )   Save The paper describes a shaped Gregorian feeds which includshorn,modified ellipsoid subrelector and dielectric body.The dielectric bodylinks horn and subreflector.The paper derives a set of equations whosesolution yields directly the both subreflector and dielectric body profilesto qive a specified amplitude and phase distribution in the main reflectoraperture.The shaped feeds has two particular advantages.First,it puts offthe support of subreflector.Next,it retains the shape of paraboloid mainreflector. Related Articles | Metrics

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A COMPARISON OF COSTS BETWEEN SATELLITE AND SPACE PLATFORMS Zhu Yilin (Chinses Academy of Space Technology) 1989, 9 (06):  31-38+22.  Abstract ( 1741 )   Save The paper presents the Cost Estimation Relationship(CER)of various components and the total lifetime for expendable satellite,recovera-ble and serviceable spaceplatforms.Finally,it compares the costs of total life-time among the three kinds of spacecraft with examples and indicates the co-nditions in which each of the three spacecrafts is most economical respectively. Related Articles | Metrics

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UDUT FACTORIZATION FILTER AND ITS APPLICATION Chen Zngui (Beijing Institute of Control Engineering) 1989, 9 (06):  39-48.  Abstract ( 9006 )   Save In this report the UDUT factorization filter algorithm is pre-sented.The whole filter formulae,including time updating and measurementupdating,have been derived by using a simple method,which is easy tounderstand by engineer.A standard and universal UDU~T factorization filtersubroutine has been writeen using FORTRAN-77.The algorithm has highnumerical stability.As a bridge between the UDU~T factorization filter theoryand engineering application,the standrad and universal subroutine has goodperformance,application flexibility and can be applied to other scientificfields. Related Articles | Metrics

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MODIFIED OSLO ALGORITHM Wang Yanguang (Beijing Institute of Satellite Information Engineering) 1989, 9 (06):  49-53.  Abstract ( 1702 )   Save In this paper,a modified OSLO algorithm,which is used tocalculate discrete B-splines and useful in computer-aided geometric design,computer graphics,image processing and pattern recognition,is presented.The new algorithm possesses an advantage over the old one in storage spacerequirement and process speed. Related Articles | Metrics

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ON RADIATION FIELD AND SURFACE WAVE EXCITED BY MICROSTRIP DIPOLE ANTENNA WITH DIELECTRICAL COVER Wang Jiasheng (Beijing Institute of Spacecraft Systems Engineering) 1989, 9 (06):  54-64.  Abstract ( 1800 )   Save On the basis of giving the Green's functions of microstripdipole antenna with dielectrical cover,its radiation field is calculated.Theexcited surface wave in this structure is analysed and some special behaviourswhich may be useful for designing microstrip dipole array and surface waveantenna are discussed, Related Articles | Metrics