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Table of Content

    24 April 1998, Volume 18 Issue 2 Previous Issue    Next Issue
    论文
    A SUMMARY OF THE ACTIVITIES ON THE SUN AROUND 260° LONGITUDES AND THEIR RADIO CHARACTERISTICS IN THE YEAR OF 1991
    ZHENG Leping;LIU Yuying
    1998, 18 (2):  97-103.  doi: 10.11728/cjss1998.02.097
    Abstract ( 1681 )   PDF (322KB) ( 1072 )   Save
    In the paper, a summary of activities on the Sun around 260° longitudes is presented and the drifts of sunspot groups and parameters of their corresponding slowly varying sources are calculated. Eight great radio bursts were observed with the 2.84GHz radio telescope at Beijing Observatory, among them, four events (1991-05-16,1991-06-09, 1991-06-11, 1991-08-25)are very similar in temporal variations. All of these bursts are well correlated with type Ⅱ, type Ⅲ, type Ⅳ radio meter band bursts.It indicates that in these active regions there are certain magnetic configurations which might be easy to produce mass coronal mass ejection.
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    ENERGY FLUX DENSITY DISTRIBUTION IN THE HIGH SPEED SOLAR WIND
    LU Xianhe;WEI Fengsi;LU Jianyong;LIU Siqing
    1998, 18 (2):  104-110.  doi: 10.11728/cjss1998.02.104
    Abstract ( 1783 )   PDF (343KB) ( 1455 )   Save
    Using the characteristical parameters of high speed solar wind observed by Ulysses,the energy flux distribution of high speed solar wind is obtained in the high latitudes.The results states clearly that the total energy flux density is about 2.1 × 10-3J·m-2·s-1 (normalized to 1AU), mainly dominated by kinetic energy flux density (about 58%)and what overcome the gravitational potential energy flux at one solar radius (about 39%). In order to drive the high speed solar wind, the input energy flux density must be over 7.1×102J·m-2·s-1 in the coronal source region of high speed solar wind.It is 40% larger than that of derivation from observations of previous satellites near the ecliptic plane. It is infered that there may exist two types of energy flux responsible for heating and accelerating the outflowing solar wind from the remote-sensing observations of the coronal source region. One has more short dissipatoon length, it will be dissipated within the very short space region (about 1-2Rs)and make the corona temperature rising up very quickly. The other is stored in the solar wind, it will be dissipated continuosly with the solar wind outflowing and accelerate the solar wind as well as heating solar wind.
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    HIGH ENERGY DELAY AND EMISSION BROADENING OF HARD X-RAYS IN SOLAR FLARES
    LIN Huaan
    1998, 18 (2):  111-118.  doi: 10.11728/cjss1998.02.111
    Abstract ( 1666 )   PDF (508KB) ( 956 )   Save
    From the well-known fact that the solar hard X-rays are produced by an energetic electron beam impinging on solar atmosphere, and based on the observational fact that there are good correlation between the solar hard X-ray flux and energy spectrum, in this paper, a source function with synchronous variation between the injecting electron beam flux and spectrum index is proposed, and some calculating results about hard X-ray temporal properties in solar flares are obtained. These results show: high energy delay and emission broadening are two manifestations of solar hard X-ray temporal properties in the nonthermal bremsstrahlung process, and the relation between them is very dominant. The lower the density of solar atmosphere where hard X-rays produced, the more distinct for high energy delay and emission broadening of solar hard X-rays.
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    RECONSIDERATION OF MHD COPLANAR RIEMANN PROBLEM
    HU Xiaolong;HU Youqiu
    1998, 18 (2):  119-125.  doi: 10.11728/cjss1998.02.119
    Abstract ( 1824 )   PDF (480KB) ( 1084 )   Save
    It is proved that a general coplanar discontinuity can be decomposed according to (这里有图片19980204-119.GIF). Here the arrow over symbol represents the propagation direction of the related outcome of decomposition, J represents the contact surface, Wf is the fast-mode wave, containing the fast shock, fast simple wave, intermediate shock of type 1→3, and the first kind of fast compound wave, and Ws is the slow-mode wave,containing the slow shock, slow simple wave, intermediate shock of type 2→4, and the first kind of slow compound wave. The decomposition of several specific discontinuities is also discussed.
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    THE FORMATION MECHANISM OF DOUBLE LAYER BY STABLE CURRENT IN PLASMA
    MA Shanjun;LI Xiaoping;YANG Qianli;LI Fuquan;ZHOU Daowen
    1998, 18 (2):  126-131.  doi: 10.11728/cjss1998.02.126
    Abstract ( 1598 )   PDF (328KB) ( 809 )   Save
    In this paper, on the basis of magnetic field produced by stable current the formation mechanism of double layer is studied in detail by solving two stream magnetohydrodynamic equations for two time-scales. The result can reasonably explains that there must be a charged particle fluid or a potential drop in plasma to produce a double layer in laboratory plasma.
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    OBSERVATIONS OF THE LONGITUDE EFFECTS IN THE MID-LATITUDE IONOSPIIERIC F-REGION AND COMRISONS WITH MODELS
    WU Jian;Quan Kunhai;CAO Zhonghui;ZHU Minghua;CAO Chong
    1998, 18 (2):  132-140.  doi: 10.11728/cjss1998.02.132
    Abstract ( 1941 )   PDF (575KB) ( 1114 )   Save
    Longitude effect in the mid-latitude F region is studied in this paper, using monthly median value f0F2 and f0F1 observed at Changchun and Urumqi,China from 1956 to 1994. Results are compared with the IRI-90 model. Physical mechanism leading to the longitude effect is discussed with the help of the IRI-90 and MSISE90 models.
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    A SEMI-ANNUAL VARIATION OF THE ATOMIC OXYGEN IN THE UPPER ATMOSPHERE
    QIN Guotai;SUN Lilin;LI Hong;LIU Jing;XU Guoliang
    1998, 18 (2):  141-145.  doi: 10.11728/cjss1998.02.141
    Abstract ( 1932 )   PDF (338KB) ( 1019 )   Save
    The long-term variation of the atmospheric composition in the Earth's upper atmosphere are controlled by 11-year cycle of the number of sunspots, varied solar and geomagnetic activity and so on. Satellite composition measurements showed that composition variations occurred. In this paper, the discussions are based on data from Satellite LDEF, and only represented in send-annual variation of the atomic oxygen (LDEF, spent 5 years and 10 months in LEO, from 1984 to 1990). The results show that a send-annual variation of the atomic oxygen is very clear, especially during the solar minimum (the mean annual sunspot number< 20). The density of the atomic oxygen changes 40%-60%, and the total amount of variations is further enhanced by the increasing of the sunspots number, while the change is up to 87% during the solar maximum (in 1989, the mean annual sunspots number > 120).
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    THE STUDY OF THE HEATING PROCESSES IN STRATOSPHERE,MESOSPHERE AND LOWER THERMOSPHERE
    XU Jiyao;WANG Yingjian
    1998, 18 (2):  146-151.  doi: 10.11728/cjss1998.02.146
    Abstract ( 1581 )   PDF (432KB) ( 1277 )   Save
    In this paper, the heating rate produced by photochemical processes in stratosphere,mesosphere and lower thermosphere is calculated. And the atmospheric cooling rate is calculated as well using Fondchev's code. Using one dimensional tine dependent photochemical model, the diurnal variation of heating rate in the height region of 20-140 km is studied. Tis work provides theoretical basis for studying the atmospheric tidal waves.
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    ZERO-CROSSING BOUNDARY OF LAPLACE-GAUSSIAN FILTERED IMAGE AND ITS FRACTAL DIMENSION
    ZHUANG Hongchun;SONG Xiang
    1998, 18 (2):  152-160.  doi: 10.11728/cjss1998.02.152
    Abstract ( 1578 )   PDF (594KB) ( 1034 )   Save
    The method of calculation of zero-crossing boundary of an observed image using replace-Gaussian filter is examined. It is shown that the determination of the zero-crossing boundary by the observed boundary is of local fashion. The deviation of the zer0-crossing boundary from the observed boundary depends mainly on the size scale L of the image, the local curvature radius ρ of the boundary, and the size constant of the Gaussian function, The deviation is smaller for smaller and large L and ρ. There are four critical values to characterize the features of the influence of σon the deviation of zero-crossing boundary from the observed boundary:wipe-out value (σ/L = 1/3), fractal value (σ/L = 1/ 10), exaggeration value (σ/L = 1/3), and deviation-free value (σ/L = 1/10). If σ/L is large than wipe-out value, the image will be wiped out by the filter and no zero-crossing boundary exists. When σ/L is less than the wipe-out value a zero-crossing boundary exists and can be obtained directly from the observed boundary. For σ/L less than the fractal value, zero-crossing boundary will faithfully thee the observed boundary and fractal dimension of the boundary curve can also be calculated. If σ/ρ is around the exaggeration value, the zero-crossing boundary will exaggerate the fluctuations in the observed boundary curve.If σ/p is less than the deviation-free value, the deviation of zero-crossing boundary from the observed boundary is not discernible. Therefore replace-Gaussian flited zero-crossing is an accurate method to locate homogeneous image boundary which the size and curvature radius are larger than 10σ.
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    ORBITAL DESIGN OF VERTICAL HITTING MOON PROBE
    XI Xiaoning;ZHU Wenyao
    1998, 18 (2):  161-167.  doi: 10.11728/cjss1998.02.161
    Abstract ( 1569 )   PDF (289KB) ( 1879 )   Save
    In this paper, the problem of orbital design of vertical hitting moon probe is discussed. The probe starts from a near-earth circular parking orbit and accelerates in the velocity direction of the parking orbit then enters the landing moon orbit and finally hits the moon with free flight, Firstly,in the constraint conditions of the parking orbit,energy limit,and the landing moon point using theories of two-body and double two-boby, not only the approximate initial values of the orbit are given,but also the characteristics of it are illustrated. Then, based on a dynamic model of general restricted four-boby, three point boundary values are searched and the high accuracy orbit of the probe is gained.
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    NONLINEAR PROPERTIES ANALYSIS OF JET COMROL PULSE MODULATORS
    GENG Yuuhai;CUI Hutao;YANG Di;SHE Haiying;LI Zhi;Qu Guangji
    1998, 18 (2):  168-173.  doi: 10.11728/cjss1998.02.168
    Abstract ( 1575 )   PDF (374KB) ( 1080 )   Save
    In this paper, nonlinear properties of two modulators are studied, one is pseudo rate modulator and the other is pulse-width pulse-frequency modulator. Nonlinear properties are discussed and studied using frequency domain method. Both digital solution and half-theory method are adopted to get the describe function, and it describes the nonlinear property accurately.
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    ROBUST VARIABLE STRUCTURE CONTROL FOR SPACE MANIPULATOR SYSTEM WITH UNCERTAIN PARAMETERS
    CHEN Li;LIU Yanzhu;WU Wenlong
    1998, 18 (2):  174-179.  doi: 10.11728/cjss1998.02.174
    Abstract ( 1626 )   PDF (260KB) ( 1666 )   Save
    In this paper, the control scheme is discussed for a free-floating space manipulatror,based on the augmented statefeedback control model. The scheme of robust variable structure control is proposed for a free-floating space manipulator,whose load parameters is uncertain, to track the desired trajectory of workspace. It is demonstrated by the simulation that the control scheme is efficient.
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    A COMPARISON OF THE MEASUREMENTS FROM TWO KINDS OF DOSIMETERS ON BOARD RECOVERABLE SATELLITES
    QI Zhangnian;CHEN Mei;LI Xianggao;JM Xianghong;HUANG Zengxin
    1998, 18 (2):  180-185.  doi: 10.11728/cjss1998.02.180
    Abstract ( 1684 )   PDF (409KB) ( 917 )   Save
    The radiation doses measured by GM counters and LiF dosimeters on board recoverable satellites for 1994 and 1996 are presented and the relation between the particle counts and the measured doses by LiF dosimeters is investigated. The average stopping power of the paricles in muscle is estimated. The results show that the ratio of the counts to the dose is constant though the shielding is quite differen. The doses measured by LiF dosimeters with the different thickness are similar and the average stopping power is estimated about 5MeV / cm. It means that the energies of the charged prides are considerably high.
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    TIME-SPACE EVOLUTION OF PEAK OCCURRENCE OF IONOSPHERIC Es IN EAST ASIA
    TAN Hui;TAN Zixun
    1998, 18 (2):  186-189.  doi: 10.11728/cjss1998.02.186
    Abstract ( 1580 )   PDF (271KB) ( 912 )   Save
    The data observed from more than twenty stations in East Asia are compared month by month. year by year and station by station. It is found that the peak of Es occurence (place of maximal occurrence of Es)is noted for time-space evolution.Generally speaking : (1)Daytime peak is situated in low latitudes in the winter. (2)The places of daytime peak vary from low to high latitudes with the sunspot number from small to lager in the summer. (3)The peak is not clear in the equinox. (4)As for night the peak is always in about 36°N latitude. Thus it can be concluded that the peak of Es occurrence is changeable with certain regularities. This is different from the conclusions in the past.
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    SOME ESTIMATED RESULTS ON TIlE ORBIT RADIAL ERRORS FROM SEVERAL NEW GEOPOTENTIAL MODELS
    ZHAO Changyin
    1998, 18 (2):  190-192.  doi: 10.11728/cjss1998.02.190
    Abstract ( 1466 )   PDF (244KB) ( 1065 )   Save
    In this paper, some results on the orbit radial errors from several different geopotential models are provided. These results indicate that JGM3 and TEG3 are superior to others and there exist large errors in present models for low orbit satellite.
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