the orbit models, the calculation methods of sub satellite and the coverage judgement which take into account the J 2 perturbations are given first, and then an iterating methods of designing satellite orbit with repeat ground trace is proposed.
The miniature star simulator introduced in the paper is a testing equipment simulating the sky on the ground, in this way the functional testing for star map recognition algorithm of a star sensor can be carried out and the simulated star map can be given at real-time.
The correlation analyses are made between the yearly-mean values of the solar constant and the critical frequency of the F_2 layers,the Stratosphere temperature, the ground temperature, and the variation of the length of a day for the period of 1979～1987. The results show that the correlation coefficieots are more than +0.8, except the correlation coefficient between the solar constant and the ground temperature is -o.
We first review the methods of VLBI maser observation and the research progress. The future VLBI observation of masers using space VLBI is then discussed in somedetail. The ground VLBI observations of masers currently under way are also mentionein support of the space VLBI observations.
Based on the equation of state of Nandan iron meteorite and the PREM model of the eaath, it is calculated that the material density at the boundary between inner core and outer core of the earth is 12.83-13.41 g/cm3 and the temperature is 5440-5680 K;
Our study indicates that the model can be applied to study the interaction between land surface processes and atmospheric boundary layers over various underlying surfaces and their regional climate effects.
Regularities of wind-erosion of different land-use types in Yongding River sandy land, Beijing
The threshold wind velocity of a number of variables was studied in four different land-use types: farm land, forestland, wild grassland and a flood plain in the Yongding River sandy land in Beijing.
The following conclusions were drawn: 1) The order of decreasing threshold of wind speed for sand displacement and surface roughness were forestland, wild grassland, farm land, sparse wild grassland and flood plain.
At a height of 0-20 cm, the height increased while the sediment discharge percent of sand flux decreased; there were significant differences in the sand flow formation under different land-use types.
We develop methods that give rise to natural monomial bases for such rings over their ground fields and explicitly determine precisely which monomials are zero in the ring of coinvariants.
Direct current magnetic susceptibility measurement in the 2-300 K temperature range supports a high-spin ground state.
Meanwhile, the measurement of water vapor in daytime has been taken, and the profiles of water vapor mixing ratio at ground level have been detected.
Low velocity target detection based on time-frequency image for high frequency ground wave radar
The Doppler spectral broadening resulted from non-stationary movement of target and radio-frequency interference will decrease the veracity of target detection by high frequency ground wave (HFGW) radar.
Exploitation of rare earth catalysts in polymer syntheses
The studies over forty years on rare earth catalysts in polymer syntheses of diene, alkyne, alkylene oxide, thiirane, carbon dioxide copolymerization, lactide, caprolactone, cyclic carbonate and so forth in China have been reviewed.
Synthesis and characterization of rare earth complexes with Phthalaldehyde-lysine Schiff base
The spectra indicate that the energy transfer takes place from the triplet excited state of MLCT (metal-to-ligand charge transfer) state for Sr2CeO4 (sensitizer) to the rare earth ions (activator).
Biological effect of rare-earth lanthanum nitrate on the growth of Escherichia coli B was studied using the calorimetric method.