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本文简要介绍美国QUALCOMM公司开发的CDMA数字蜂窝系统,包括基本概念、优点、系统设计以及向CDMA的过渡。 相似文献
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本文介绍了国际通信卫星组织INTELSAT卫星传播实验、欧洲OLYMPUS卫星传播实验、意大利ITALSAT卫星传播实验以及日本和澳大利亚开展的移动通信卫星传播实验的概况。 相似文献
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B. M. Sankey 《加拿大化工杂志》1985,63(1):3-7
Development of a new process for the solvent extraction of lubricating oils, known as EXOL N, is described. The selection of N-methyl-2-pyrrolidone (NMP) as solvent, the determination of its relevant properties, and its application through engineering and pilot-plant studies are reviewed. This EXOL N process is now employed internationally in over a dozen full-scale lube extraction plants. 相似文献
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The rat acoustic cortex has been studied at light optic and ultrastructural levels under the white noise stimulation. After the noise stimulation for 7 days, micropunctate hemorrhages, proliferation and hypertrophy in cells of microglia and astrocytic glia are noted. After the noise stimulation for 21 days, the neuroglial reaction becomes less pronounced, there are no hemorrhages, a great amount of neurons with peripheral and total chromatolysis appear. In other neurons, as well as in all types of neuroglia the number of primary lysosomes increases, their structure changes. In lysosomes lipofuscin and lipid drops are accumulating, many of lysosomes turning into multivesicular bodies. The destructive changes observed in the neurons and neuroglia underlie prolonged disturbances in the higher neural activity after the noise stimulation is stopped. 相似文献
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Blood serum of oncologic patients due to immunoglobulin involved in its composition, activates glycolysis in the soluble fraction of muscles when using starch, glycogen and glucose as substrates. The activation is registered under both aerobic and anaerobic conditions. When elucidating the immunoglobulin effect in a glycolytic chain under aerobic conditions it is shown that its activating effect in the incomplete incubation system is manifested with such glycolysis substrates as fructose-6-phosphate and 2-phosphoglyceric acid. Glycolysis activation with serum is insignificant or absent at all with the presence of glucose-6-phosphate, fructose-1,6-diphosphate, 3-phosphoglyceric aldehide, 3-phosphoglyceric acid, phosphoenolpyruvic acid, sodium pyruvate. Immunoglobulin isolated from the blood serum of oncologic patients does not affect the activity of purified preparations of hexokinase, glycerinaldehydephosphate dehydrogenase, lactate dehydrogenase under aerobic and anaerobic conditions. When using the air as a gas medium lactate dehydrogenase is activated by immunoglobulin. Lactate dehydrogenase activity under aerobic and anaerobic conditions is essentially lower than in the case when the air serves as a gas medium. 相似文献