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991.
通过郑州航空大酒店工程实例,阐述了粉体喷射搅拌在深基开挖构建防渗止水围幕的设计原则,方法和主要的计算依据及其主要参数确定的试验方法和数据分析;介绍了施工中特殊的工艺技术措施和取得的效果,提出了该工法值得进一步探讨的几个问题。 相似文献
992.
Dengkai Jiang Zhanwen Han Cheng Liu Jiancheng Wang Lifang Li 《Astrophysics and Space Science》2010,329(1-2):283-286
According to the prevenient theoretical study, the minimum mass ratio for tidal stability of W Ursae Majoris (W UMa) systems is q min?=(M 2/M 1)~0.071–0.078. However, the mass ratios of some observed W UMa binaries are smaller than the theoretical minimum mass ratio. Using Eggleton’s stellar evolution code, we study the effects of metallicity and evolution on the minimum mass ratio of W UMa systems (M 1=1.2M ⊙). We assume that $k_{1}^{2}=k_{2}^{2}$ for the component’s dimensionless gyration radii and that the contact degree is about 70 per cent. We find that the dynamical stability of W UMa binaries depends on the metallicity of W UMa systems. For the W UMa systems at age = 0 Gyr, the distribution of the minimum mass ratio has a fairly wide range, from 0.083 to 0.064, with the metallicity range from Z=0.0001 to 0.03. W UMa systems with Z=0.01 have the smallest value of the minimum mass ratio, which is about 0.064. The existence of low-q systems can be explained partly by the dependence of the dimensionless gyration radius on the metallicity. In addition, the dependence of the minimum mass ratio on the evolution, as suggested by previously work, is confirmed. 相似文献
993.
Shang Wang Raymond M. Dong Christina Z. Dong Liuqin Huang Hongchen Jiang Yuli Wei Liang Feng Deng Liu Guifang Yang Chuanlun Zhang Hailiang Dong 《地学前缘(英文版)》2012,3(3):335-349
The Three Gorges Dam(TGD) of the Yangtze River.China,is one of the largest irrigation and hydroelectric engineering projects in the world.The effects of huge man-made projects like TGD on fauna and macrophyte are obvious,mainly through changes of water dynamics and flow pattern;however, it is less clear how microorganisms respond to such changes.This research was aimed to examine differences in microbial diversity at different seasons and locations(in front of and behind the TGD).In addition, differences between particle-attached and free-living communities were also examined.The community structures of total and potentially active microorganisms in the water columns behind and in front of the TGD were analyzed with the DNA- and RNA-based 16S rRNA gene phylogenetic approaches over three different seasons.Clone libraries of 16S rRNA genes were prepared after amplification from extracted DNA and.for some samples,after preparing cDNA from extracted rRNA.Differences were observed between sites at different seasons and between free-living and particle-attached communities.Both bacterial and archaeal communities were more diverse in summer than in winter, due to higher nutrient levels and warmer temperature in summer than in winter.Particle-attached microorganisms were more diverse than free-living communities,possibly because of higher nutrient levels and heterogeneous geochemical micro-environments in particles.Spatial variations in bacterial community structure were observed,i.e..the water reservoir behind the TGD(upstream) hosted more diverse bacterial populations than in front of the dam(downstream),because of diverse sources of sediments and waters from upstream to the reservoir.These results have important implications for our understanding of responses of microbial communities to environmental changes in river ecosystems affected by dam construction. 相似文献
994.
山西省降水与环流特征量及ELnino的关系 总被引:2,自引:1,他引:2
本文通过滑动相关普查方法,对山西30个代表站点的夏半年(6-11月)降水与前期74个环流特征量及北太平海海温月平均资料作逐点逐月普查相关分析,结果表明:上年7-10月的南方涛动指数及赤道东太平洋(ELnino区)海温与我省夏半年降水分别有很好的相关关系,它们的出现对山西夏半年降水影响是非常强的,同时还发现前期多个环流指数如太阳黑子、西太平洋副高与我省夏半年降水也有很好的相关关系。 相似文献
995.
996.
Dehydration melting of solid amphibolite at 2.0 GPa: Effects of time and temperature 总被引:3,自引:0,他引:3
ZHOU Wenge XIE Hongsen LIU Yonggang ZHENG Xiaogang ZHAO Zhidan & ZHOU Hui . Laboratory of Material in the Earth’s Interior Institute of Geochemistry Chinese Academy of Sciences Guiyang China . Department of Geology China University of Geosciences Beijing China . Department of Geology Peking University Beijing China 《中国科学D辑(英文版)》2005,48(8):1120-1133
The dehydration melting of the natural rock at high pressure is important to investigating the magma formation in the earth’s interior. Since the 1970s, a lot of geological scientists have paid more atten- tion to the dehydration melting of the natural rock[1―5]. Previous experiments of dehydration melting and observations of fieldwork argued that the dehy- dration melting of the rock was probably the most important fashion for the melting of the lower crust rock[6―12]. The genesis of most … 相似文献
997.
Summary A three-dimensional, nonhydrostatic numerical model with high spatial resolution, in which a simple energy closure scheme
is employed, has been developed to simulate the spray dispersion over complex terrain. The evaporation, condensation, and
dispersion of the spray and moisture are taken into account in model equations. The term of latent heat due to phase transformation
is considered in detail to account for its effects on the temperature field and airflow. As an application of the model, the
spray concentration and air relative humidity are calculated under neutral condition. The results indicate that under the
neutral condition, the spray is transported to about 0.6 km downwind from the source, and its effects on the air humidity
reach a further distance of 0.9 km downwind from the source.
Attention is given to the dependence of the results upon the various factors influencing the simulation, such as the intensity
of the source, the atmospheric stratification, and the dynamic factor of the terrain. Some numerical tests were carried out
to provide extra insight to the effects of these factors. It has been demonstrated that the simulation results such as relative
humidity and temperature are sensitive to these factors, especially to the thermal stratification. Under unstable conditions,
the effects of the spray source increase significantly, and the variation extent of the temperature, relative humidity and
flow field is larger than that under neutral condition. The effects of dynamic and thermal factors on the air flow field are
discussed through the comparison of the modeling results over complex terrain and flat terrain.
Received June 8, 1998 Revised April 17, 1999 相似文献
998.
如何更精确高效地模拟大型、复杂系统内域的波动是发展和完善近场波动数值模拟技术的一个重要研究课题。内域波动的数值模拟通常采用计算量较小的显式方法,但现有的时空解耦显式有限元方法的精度只有二阶;低精度不仅影响数值模拟的精度,而且制约着计算效率的提高。鉴于此,本文旨在探索内域波动数值模拟具有更高精度且稳定的显式方法。作者发展了内域波动数值模拟的现有显式有限元解耦技术,提出了一种高精度且稳定的显式数值模拟方法。 相似文献
999.
自流井水温固体潮效应及其应变响应能力 总被引:2,自引:1,他引:2
井水温度观测是一项重要的地震前兆观测手段,旨在捕捉地震孕育过程中的应力-应变信息。水温固体潮效应作为地壳应力-应变信息的真实反映和地震前兆观测的干扰因素,具有重要的研究意义。本文首先依据对自流井中热状态的分析,认为自流井水温固体潮效应可能主要存在两种机制,即热传导机制和热对流机制;据此,推导出热传导机制中水温与固体潮体应变变化的定量关系;最后以流量相对较大的本溪自流井为例进行分析。结果表明,本溪井水温固体潮效应是热传导机制和热对流机制共同作用的结果,其中,热传导机制起主要作用。 相似文献
1000.
Under normal temperature, the creep experiments with complete samples of Gabbro and Marble rocks are made under uniaxial compression.
It is found that at the instantaneous creeping stage, AE activities increase with loading; at the steady creeping stage, large
AE signals may appear at lower background of AE action, andm—value which shows the relationship between AE amplitude and frequency keeps stable on the low value or decreases; at the
accelerate creeping stage, AE activities increase andm—value decreases quickly or decreases again after recovery. These experimental results are related to the quality of the samples.
In this paper, AE activities during three stages of creeping process are connected with the seismic patterns (for exampleb—value, foreshocks). Finally, it is pointed out the possibility that the foreshock—mainshock—aftershock earthquake sequence
has been formed by the mechanism of creep fracture of crustal rocks.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 104–112, 1991.
This subject is sponsored by the Chinese Joint Seismological Science Foundation. 相似文献