Spacecrafts with the pure gravity environment are of great significance in precision navigation, gravity field measurement for celestial bodies, and basic physics ex- periments. The radiometer effect is one of the imp...Spacecrafts with the pure gravity environment are of great significance in precision navigation, gravity field measurement for celestial bodies, and basic physics ex- periments. The radiometer effect is one of the important interfering factors on the proof mass in a purely gravitational orbit. For the gravity field measurement system based on the inner-formation flying, the relationship between the radiometer effect on the inner- satellite and the system parameters is studied by analytical and numerical methods. An approximate function of the radiometer effect suitable for the engineering computation and the correction factor are obtained. The analytic results show that the radiometer effect on the inner-satellite is proportional to the average pressure while inversely pro- portional to the average temperature in the outer-satellite cavity. The radiometer effect increases with the temperature difference in the cavity, and its minimum exists when the cavity radius increases. When the minimum of the radiometer effect arrives, the ratio of the cavity radius to the inner-satellite radius is 1.189 4. This constant is determined by the spherical cavity configuration and independent of the temperature and pressure distributions. When the ratio of the cavity radius to the inner-satellite radius is more than 10, it is believed that the cavity is large enough, the radiometer effect is approxi- mately proportional to the square of the inner-satellite radius, and the influence of the outer-satellite cavity radius on the radiometer effect can be ignored.展开更多
The most serious potential hazard of cowpea product is the pesticide residue for controlling such pests as thrips and cowpea pod borer. To explore a safe and efficient mode of cowpea production that is fit for climati...The most serious potential hazard of cowpea product is the pesticide residue for controlling such pests as thrips and cowpea pod borer. To explore a safe and efficient mode of cowpea production that is fit for climatic characteristics of Hainan, ensure the safety of cowpea supply, minimize the use of pesticides, and control pests in physical means, insect-proof nets are applied in cowpea cultivation. We set 5-mm, 2.5-mm and 1.67-ram insect-proof nets as three treatments and open filed cultivation as CK to explore efficiency of insect-preof net in cowpoa production in terms of insect-proof efficiency, biological characters and commodity properties and yield of cowpea. The results showed that insect-proof cultivation was efficient in controlling pests, especially the 2.5-mm net showed the optimal effect for cowpea production.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 11002076)the National Defence Preresearch Foundation of China (No. 51320010201)
文摘Spacecrafts with the pure gravity environment are of great significance in precision navigation, gravity field measurement for celestial bodies, and basic physics ex- periments. The radiometer effect is one of the important interfering factors on the proof mass in a purely gravitational orbit. For the gravity field measurement system based on the inner-formation flying, the relationship between the radiometer effect on the inner- satellite and the system parameters is studied by analytical and numerical methods. An approximate function of the radiometer effect suitable for the engineering computation and the correction factor are obtained. The analytic results show that the radiometer effect on the inner-satellite is proportional to the average pressure while inversely pro- portional to the average temperature in the outer-satellite cavity. The radiometer effect increases with the temperature difference in the cavity, and its minimum exists when the cavity radius increases. When the minimum of the radiometer effect arrives, the ratio of the cavity radius to the inner-satellite radius is 1.189 4. This constant is determined by the spherical cavity configuration and independent of the temperature and pressure distributions. When the ratio of the cavity radius to the inner-satellite radius is more than 10, it is believed that the cavity is large enough, the radiometer effect is approxi- mately proportional to the square of the inner-satellite radius, and the influence of the outer-satellite cavity radius on the radiometer effect can be ignored.
文摘The most serious potential hazard of cowpea product is the pesticide residue for controlling such pests as thrips and cowpea pod borer. To explore a safe and efficient mode of cowpea production that is fit for climatic characteristics of Hainan, ensure the safety of cowpea supply, minimize the use of pesticides, and control pests in physical means, insect-proof nets are applied in cowpea cultivation. We set 5-mm, 2.5-mm and 1.67-ram insect-proof nets as three treatments and open filed cultivation as CK to explore efficiency of insect-preof net in cowpoa production in terms of insect-proof efficiency, biological characters and commodity properties and yield of cowpea. The results showed that insect-proof cultivation was efficient in controlling pests, especially the 2.5-mm net showed the optimal effect for cowpea production.
