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91.
92.
A more objective statistical technique is applied directly to the four time series used in Paper I. The empirical probability density functions indicate that the measurements are realizations of a narrow-band random process with Gaussian statistics. This result allows quantitative statistical use of the mean autocorrelation function. For example, a characteristic correlation time is 23 min, and the motion becomes statistically uncorrelated over intervals greater than 40 min. The mean autocorrelation function is found to be free of secondary maxima that have been so troublesome in other analyses. The question raised in this paper is whether our statistical model of the motion as a Gaussian random process is also applicable to smaller regions on the order of 1 to 2 in size.The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
93.
Xuefu Liu Aigen Li He Huang Fangjun Lu Guangwei Cha 《Astrophysics and Space Science》1993,205(2):359-380
We had observed the high-resolution H profiles of fourteen chromospherically active binaries which are And, 3 Cam, 4 UMi,
2 Sgr, Sgr, HR 7333, 33 Psc, UMi, And, UMa, 12 Cam, And, Aur and Dra from August 1990 to August 1991. The H emission and absorption equivalent widths, and the half widths and the radial velocities of these systems were determined. These data have a good supply for the information of the catalog of chromospherically active binary stars. The H profiles of HR 7333, 12 Cam, 4 UMi, UMi and And show marked emission filling in core, but 33 Psc, Sgr, Sgr and And systems show the H as the stronger absorption lines. The observed fourteen binaries presented very different activity levels. 相似文献
94.
Yu. N. Korenkov Carl W. Cable Vernon F. Cormier Vassily Levin Jacek A. Majorowicz Yehuda Bock Waclaw M. Zuberek Teng-fong Wong William L. Power Gary A. Robbins Piotr Raczka Krzysztof E. Haman Katarzyna Chałasinska-Macukow Ryszard Balcer Henryk Piwkowski 《Pure and Applied Geophysics》1991,137(3):309-336
95.
黄河柴家峡水电站坝址区地震动参数研究 总被引:1,自引:0,他引:1
本文结合柴家峡水电站坝址区的地震地质环境、历史地震特征以及场地条件,采用考虑地震分布时空不均匀性的综合概率法,对场区进行了地震危险性分析,在此基础上给出了坝址区50年超越概率63.2%、10%、2%三个概率水准的设计地震动参数,为大坝的抗震设计和安全运营提供了依据。 相似文献
96.
陈村水电站坝基丙凝加强帷幕的防渗时效分析 总被引:5,自引:0,他引:5
丙凝是一种曾流行过的化灌材料,形成帷幕体的防渗时效如何过去还很少有报道和研究。本文以陈村水电站为例,根据多年的观测资料、现场调查及室内测试等成果,经过综合分析,指出第7-17坝段丙凝加强帷幕的总体防渗减压效果是显著的且较稳定的。但局部的防渗效果是在衰减。今后,对这种异常部位应加强观测,以确保大坝的安全运行。 相似文献
97.
98.
Effects of dynamic soil behavior and wave non-linearity on the wave-induced pore pressure and effective stresses in porous seabed 总被引:1,自引:0,他引:1
Most previous investigations for the wave-induced soil response have only considered the quasi-static soil behavior under linear wave loading. However, it is expected that the dynamic soil behavior and wave non-linearity will play an important role in the evaluation of wave-induced seabed response. In this paper, we include dynamic soil behavior and wave non-linearity into new analytical models. Based on the analytical solution derived, the effects of wave non-linearity on the wave-induced seabed response with dynamic soil behavior are examined. Numerical results demonstrate the significant effects of wave non-linearity and dynamic soil behavior on the wave-induced effective stresses. The applicable range of dynamic and quasi-static approximations is also clarified for engineering practice. 相似文献
99.
Hydrogeochemical characteristics of surface water and groundwater in the karst basin,southwest China 总被引:1,自引:0,他引:1
Groundwater is a very significant water source used for irrigation and drinking purposes in the karst region, and therefore understanding the hydrogeochemistry of karst water is extremely important. Surface water and groundwater were collected, and major chemical compositions and environmental isotopes in the water were measured in order to reveal the geochemical processes affecting water quality in the Gaoping karst basin, southwest China. Dominated by Ca2+, Mg2+, HCO3? and SO42?, the groundwater is typically characterized by Ca? Mg? HCO3 type in a shallow aquifer, and Ca? Mg? SO4 type in a deeper aquifer. Dissolution of dolomite aquifer with gypsiferous rocks and dedolomitization in karst aquifers are important processes for chemical compositions of water in the study basin, and produce water with increased Mg2+, Ca2+ and SO42? concentrations, and also increased TDS in surface water and groundwater. Mg2+/Ca2+ molar ratios in groundwater decrease slightly due to dedolomitization, while the mixing of discharge of groundwater with high Mg2+/Ca2+ ratios may be responsible for Mg2+/Ca2+ ratios obviously increasing in surface water, and Mg2+/Ca2+ ratios in both surface water and groundwater finally tending to a constant. In combination with environmental isotopic analyses, the major mechanism responsible for the water chemistry and its geochemical evolution in the study basin can be revealed as being mainly from the water–rock interaction in karst aquifers, the agricultural irrigation and its infiltration, the mixing of surface water and groundwater and the water movement along faults and joints in the karst basin. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
100.
一次华南暴雨过程的数值模拟和试验 总被引:14,自引:9,他引:5
本文利用有限区域数值预报模式MM4对一次华南暴雨过程进行了数值模拟和试验.用该模式预报的形势场与实况较一致,预报的暴雨强度、位置也与实况相近.此外由控制试验和敏感性试验可知,该暴雨强度对地形、辐射和下垫面过程比较敏感. 相似文献