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941.
942.
Ma Zongjin Zhang Peizhen Hong Hanjin and Gao Xianglin Institute of Geology SSB Beijing China 《中国地震研究》1997,(1)
Although great-progress has been made in the earth sciences,some fundamental problems of geodynamics remain unsolved.They are concerned with the whole earth as well as regional tectonics,such as the west Pacific and Qinghai-Xizhang plateau.The new generation of earth observation by space-based measurement will contribute to solving these problems of geodynamics.In this regard,some specific plans about application of these techniques are suggested in this paper. 相似文献
943.
James M. Roberts Andrew O. Langford Paul D. Goldan Fred C. Fehsenfeld 《Journal of Atmospheric Chemistry》1988,7(2):137-152
The applicability of the tungsten oxide denuder tube technique for the measurement of ammonia in the rural troposphere was investigated. The technique is based on selective chemisorption of NH3 from a gas stream, thermal desorption, conversion to NO, and analysis by NO–O3 chemiluminescence. Nitric acid, which is also collected and desorbed as NO, was distinguished from NH3 by differences in desorption temperature. Substituted amines were also collected, but desorbed at a slightly lower temperature than NH3 in dry air. At high relative humidities, alkylamines may be hydrolyzed to NH3 on the denuder surface and hence detected as NH3. Overheating of the denuder tube during the temperature-programmed desorption was found to cause significant irreversible degradation of system performance.The technique was used to measure NH3 mixing ratios at two rural locations in the United States. At a mountain site in Colorado during the winter of 1984, the average NH3 mixing ratio was 0.20 ppbv (=0.08 ppbv). At an isolated coastal site in northern California during the spring of 1985, the average NH3 mixing ratio was 0.36 ppbv (=0.17 ppbv). Correlations of the latter measurements with wind direction and NO
x
level suggest that the NH3 mixing ratio in Pacific marine air at 40°N is <-0.25 ppbv. 相似文献
944.
945.
本文讨论了3cm天气雷达在兰州地区定量测量降水及其精度;分析了不同降水类型和衰减等对测量的影响;讨论了地面雨量计订正雷达测量值的方法和效果。 相似文献
946.
947.
张永生 《武汉大学学报(信息科学版)》1989,(2)
本文从理论上分析了近景摄影测量光束法自由网联合平差的特点,借助于该方法对卫星地面站Cassegrain通讯天线抛物反射面的实际摄影资料进行平差处理,取得了较好的点位精度。 相似文献
948.
V. I. Kondaurov 《Pure and Applied Geophysics》1986,124(4-5):749-757
In this paper the processes of rock deformation are discussed, which are accompanied by an accumulation of defects or by continuous fracturing. The influence of fluids and of the electrical and magnetic fields is neglected. A model of fracturing, based on some energy consideration is introduced. 相似文献
949.
950.
We present 1-D eddy diffusion model calculations of the distributions of propane and acetone in the atmosphere for continental conditions. The magnitude of the surface seasonal variation in propane mixing ratios that we obtain is in general agreement with measurements at the surface and in the free troposphere. A comparison of the absolute values of the model with propane measurements suggests that a larger surface flux than we have used may be more appropriate for continental conditions. The acetone model results for summer conditions that we obtain are also in reasonable accord with measurements. However, we find serious disagreement between the model winter profiles of acetone and the measurements at the tropopause and in the lower stratosphere. The measured values are lower than the model values at 45° N by a factor of 7–30. In addition, it is also surprising that, given the relatively long lifetime of acetone, free tropospheric values of acetone more representative of surface values have not been measured. The results simulating the decay of elevated levels of propane in the upper troposphere caused by rapid convective transport of boundary layer air indicate that propane will be primarily dispersed by transport rather than destroyed photochemically. Thus, the impact on acetone and PAN is minimal. 相似文献