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961.
Guiping Feng S. Jin T. Zhang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Sea level changes are threatening the human living environments, particularly along the European Coasts with highly dense population. In this paper, coastal sea level changes in western and southern Europe are investigated for the period 1993–2011 using Global Positioning System (GPS), Tide Gauge (TG), Satellite Altimetry (SA), Gravity Recovery and Climate Experiment (GRACE) and geophysical models. The mean secular trend is 2.26 ± 0.52 mm/y from satellite altimetry, 2.43 ± 0.61 mm/y from TG+GPS and 1.99 ± 0.67 mm/y from GRACE mass plus steric components, which have a remarkably good agreement. For the seasonal variations, annual amplitudes of satellite altimetry and TG+GPS results are almost similar, while GRACE Mass+Steric results are a little smaller. The annual phases agree remarkably well for three independent techniques. The annual cycle is mainly driven by the steric contributions, while the annual phases of non-steric (mass component) sea level changes are almost a half year later than the steric sea level changes. 相似文献
962.
生源质量关乎学校的人才培养质量,是学校赖以生存与发展的命脉,招生宣传是提高生源质量的重要手段。通过对我校2013级新生生源的调查研究,利用EXCEL统计学软件对调查结果进行了详尽的统计和分析,并以此为依据探究合理、有效的招生宣传策略。 相似文献
963.
低成本IMU/GPS组合导航系统研究 总被引:2,自引:0,他引:2
GPS/INS组合导航系统已在一定领域得到应用,而INS昂贵的价格限制了它的广泛应用,本文采用低成本惯性测量组件(IMU)设计了低成本IMU/GPS组合系统的硬件和相应的软件,进行了静态实验和数据处理,系统的俯仰角和横滚角误差均小于0.2°,实验结果表明,低成本组合系统的性能较好,而其性能价格比更高。 相似文献
964.
965.
高压液氧供应系统是我国压力最高的挤压式液体火箭发动机试验台的关键分系统。在系统设计过程中,通过合理布置管路,设计专用固定支架,采用自然补偿和堆积绝热技术,解决了高压低温推进剂系统管路设计中的难题。该系统顺利通过气密性检查和调试,经多次热试车考核,系统稳定可靠,满足设计要求。 相似文献
966.
Li-xue Zou Shao-yan CuiJian Zhong Zong-chun YiYan Sun Yu-bo FanFeng-yuan Zhuang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
Hematopoietic progenitor cell proliferation can be alternated on either spaceflight or under simulated microgravity experiments on the ground; however, the underlying mechanism remains largely unknown. In the present study, we have demonstrated that exposure of human erythropoietin (EPO)-dependent leukemia cell line UT-7/EPO cells to conditions of simulated microgravity with a rotary culture instrument significantly inhibited the cellular proliferation rate. Adding higher concentrations of EPO to the culture medium failed to improve the inhibitory status. Cell apoptosis was detected by fluorescence staining of cell nuclei and a flow cytometry assay using Annexin V/PI double staining. This microgravity-induced apoptosis in UT-7/EPO cells could be blocked by a pancaspase inhibitor Z-VAD-FMK. Immunoblotting demonstrated that rotary culture resulted in a reduction of the expression of Bcl-xL, an anti-apoptotic protein, and the cleavage of caspase-3. Furthermore, rotary culture reduced surface localization and protein content, as well as the mRNA expression of erythropoietin receptor (EPOR) of UT-7/EPO. Take together, the findings indicated that simulated microgravity may induce mitochondrial related apoptosis of UT-7/EPO cell through depressing the EPO–EPOR pathway. 相似文献
967.
Hong Wu Congli Huang Keping Zhang Yeqing Sun 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
Cauliflower and sprout broccoli are widely planted vegetables particularly in Fujian Province, China. To study the mutation in these two types of vegetables induced from spaceflight, we flew the seeds on the 20th Chinese recoverable satellite which orbited the Earth for 18 days. After returning to the Earth, the cauliflower seeds were planted for two generations and the sprout broccoli seeds for one generation at the Xiamen Agriculture Research Institute. Of the 12 cauliflowers planted for the first generation, two showed significant phenotypical changes in both the size of the plant and the weight of the flower head. In addition, most of the space flown plants were found to be resistant to the black rot attack in the field. Cauliflowers planted for the second generation from the seeds in one of the two plants that displayed phenotypical changes in the first generation showed similar mutations. For the first generation of sprout broccoli, the rate of emergence from the flown seeds was lower than that of the control by 30%. No significant changes in the phenotype between the sprout broccolis planted from the flown seeds and the control were observed except one of the mutated sprout broccolis showed a change in the appearance in the lesser bud of the chief flower head. Results of the study demonstrated that DNA damages in some of the genes may have occurred in the seeds flown in space, and some of the changes in the genes may have inherited from the first to the second generation. The improved resistance to the black rot attack and increased size of the flower head are apparently beneficial. 相似文献
968.
作为存储市场的领先者,Sun比全球其他企业都保护和管理着更多的数字归档数据.可以为用户提供整合的解决方案,帮助简化IT基础设施、降低成本、安全方便地实现从创建到删除的数据管理. 相似文献
969.
风险投资中有三类经典优化模型,分别是风险极小化模型、期望收益极大化模型、风险厌恶模型。这三类模型的等价会为投资组合分析提供更多的方法。文中证明了三类优化模型产生相同的有效前沿,并在此意义下得出这三类优化模型的等价性。另外,引用MSCI世界股价指数数据对三个模型有效前沿的等价性,进行实际算例验证。 相似文献
970.