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25 October 1987, Volume 7 Issue 05 Previous Issue    Next Issue

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DEVELOPMENT OF A SELF—LUBRICATING COMPOSITE MATERIAL AND ITS APPLICATION Qu Yongxing Qiu Guonian Xie Xuezhi (Luo yang Institute of Bearings) 1987, 7 (05):  1-8+26.  Abstract ( 1826 )   Save A self-lubricating composite material with refractory metal tentalum matrix developed by hot pressing and sintering process in powder matallurgy and its application are presented. The friction and wear behaviors of the material in air and the structure analysis for the lubricating phase of the material are discussed. The life of rolling bearings with cages made of this material was tested in high vacuum condition and the results of the tests showed that the cages had satisfactory performance and efficient Lubrication for the bearings. Related Articles | Metrics

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FREQUENCY CONVERSION PROCESS AND FREQUENCY SYNTHESIZER OF METEOROLOGICAL SATELLITE RECEPTION EQUIPMENT Zhou Manlin 1987, 7 (05):  9-17.  Abstract ( 1968 )   Save This paper presents a method which combines the design of the freguency synthesizer with the design of a receiver, in order to receive all frequency band of meteorological satellite, for obtainning a optimum performance to cost ratio. For the purpose of automatic designing of receiver, there are computer interface circuits in frequency synthesizer. This means that computer may be connected directly to frequency synthesizer. Therefore the digital phase-locked technigues are used in meterological satllite reception equipment. In this paper we analys noise performance of phase-locked loop. The task in the design of a digital phase-locked frequency synthesizer, therefore, is to try to decrease the amplitude of interference spectrum. Related Articles | Metrics

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COMPUTING SATELLITE DRAG COEFFICENTS BY THE SCHEMBERG METHOD Zhou Qicheng 1987, 7 (05):  18-26.  Abstract ( 1784 )   Save Since Schemberg's Particle-surface interaction mode in "hyperthermal free molecula flow" represents the inter-action of high atmosphere molecules with the wall material of spacecraft more really, it can be used to calculate the drag coefficients of satellites. In this paper the basic principles of the mode are presented, the calculation formulae of drag coefficients for the satellite with simple geometric shapes are listed and the computing results are given. Related Articles | Metrics

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REPRESENT DIGITAL PICTURE BY GD AND GD13 REPRESENTATIONS Wang Yanguang (Beijing Institute of Satellite Information Engineering) 1987, 7 (05):  27-39.  Abstract ( 1695 )   Save In this paper, first, a linear quadtree representation——GD (standing for)representation is given. And its space requirement is the same as CD's. Then, the relations between GD and CD, GD and QC are discussed, and several conversion algorithms, such as matrix to GD, GD to matrix, raster to GD are given. Finally, for 256-level picture, the GD13 method—the voriant of GD is obtained. It's worth mentioning that the space requirement of GD13 method is not more than that of matrix method. Related Articles | Metrics

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DESIGN OF TEST FACILITY SIMULATING SATELLITE MAGNETOSPHRE SUBSTORM ENVIRONMENT Song Yougao (Beijing Institute of Environment Test Engineering) 1987, 7 (05):  40-44.  Abstract ( 1728 )   Save The Charging of satellite surface is discovered early in the seventies. This is a new trouble harming geosynchronous orbit satellite. In order to provide a new method for solving the problem of charging of satellite surface, many people have mode a wide-ranging research.We started the research of charging technique of satellite surface in 1982,In this paper, the issues considered in design of the facitity simulating magnetosphere substorm environment are introduced. Requirements for simulating system and the composition and uses of simulating system are clarified. The design of vaccum system, elecfron gun, light source and surveying instruments are briefly described. Related Articles | Metrics

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THERMAL EXPANSION—ONE OF THERMOPHYSICAL PROPERTIES OF CARBON FIBER/EPOXY-RESIN COMPOSITES Zhang Jianke (Lanzhou Physics Institute) 1987, 7 (05):  45-50+69.  Abstract ( 2417 )   Save In this paper, the thermal expansion mechanism of Carbon Fiber/Epoxy-Resin Composites and theoretical calculation of the thermal expansion have been discussed. The effects of fiber arrangement and temperature on the coefficient of thermal expansion of CFRP have been summarized. Some of the data about the coefficient of thermal expansion of CFRP have been given. Related Articles | Metrics

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STUDY OF CHARGING BEHAVIOUR OF SPACECRAFT SURFACE MATERIALS EVALUA TION OF RTV—Ⅱ AND 13—17 PAINTS Lu Yusun, Li Hua, Wang Neidong, Liu Yukui (Lanzhou Physics Institute) 1987, 7 (05):  51-57.  Abstract ( 1954 )   Save In this article, the experimental results of response of the conductivity vs combined environment about RTV-Ⅱ paint and the 13-17 white thermal control paint have been given. The experiments show that first: the conductivity of RTV-Ⅱ almost drops by one order of magnitude every year from 1984 to 1986. Therefore, the change of charging state occures on its surface. second: the response of conductivity of 13-17 paint vs space vacuum is not obvious, but the response of conductivity vs electron and light irradiation is very large. Especially, there is a strong memory effect under light irradiation. It is expected that the charging phenomenon on the paint surface does not appear in orbit when the spacecraft goes into eclipse from sunshine. Related Articles | Metrics

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APPLICATION OF ZINC—BASE ALLOY DIE Li Hongyi 1987, 7 (05):  58-63.  Abstract ( 1987 )   Save Zinc-base alloy die is suitable for small and medium batch production. Its material is Zinc-base alloy and its cost is cheap. The alloy is used instead of steel and cast iron. The mould can be manufactured by casting and the technigue is simple, without requiring precision machines and special heat treatment equipments. The alloy is used in manufacturing main parts of scalping die, drawing die. bending die, stamping die, plastic die and accessory parts of mould. The die can be used to scalp metal plate the thickness of which is about 0.8 to 4 mm and some non-metal plates. Presently, it is widely used in electrical industry, light industry and automobile industry, its application has achieved obvious economic benefits. This paper describes chemical composition and mechanical properties of Zinc-base alloy,the mechansims of Zinc-base alloy die, technology process, economic benefits of the die, and some ways of improving the quality of casting the die. Related Articles | Metrics

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A DISCUSSIONON FITTING ACCURACY OF OSCILLATING MIRROR IN OBJECT SPACE OF MULTISPECTRAL REMOTE SENSOR Han Xinzhi (The First Department, Harbin Institute of Technology) 1987, 7 (05):  64-68.  Abstract ( 1724 )   Save The discussion on fitting accuracy of oscillating mirror in object space is given in this paper. And its effects on performances of the sensor are explained. How to determine the fitting accuracy on the basis of the given deviation can be found by given calculating method and example. Related Articles | Metrics