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991.
史维浚 《华东地质学院学报》1986,(2)
本文给出了控制水中铀形式分市的 PH 和配位体浓度参数,对天然水中铀存在形式进行模拟电算,并总结了其分布规律。同时,还指出:在常温常压的氧化条件下,PH>8的天然水中铀通常以UO_2(CO_3)_4~(4-)为主;在50.03~0.5毫克/升时。铀应以 UO_2(HPO_4)_2~(2-)为主;在 PH<5的酸性水中铀依次受 F~-、SO_4~(-2)和∑PO_4浓度的控制,当上述离子小于零态值时,水中铀形式主要是 UO_2~(2 )。 相似文献
992.
993.
994.
西南天山构造地层学初步研究 总被引:16,自引:1,他引:16
西南天山造山带可划分为伊犁中天山、中天山南缘、南天山和塔里木4个构造地层区。伊犁中天山区出露早元古代变质结晶基底及晚期地台型稳定盖层。中天山南缘区产出一套早古生代变质俯冲杂岩。南天山区早古生代为陆坡、陆棚相被动陆缘沉积,晚古生代发育洋壳建造。塔里木区北部出露中晚元古代“优地槽建造”的变质结晶基底和早震旦世后稳定盖层。 相似文献
995.
Xia Wenchen Zhou Jie Lei Jianxi Zhang Nianmao Peng YangChina U niversity of Geoscience W uhan Hubei Wang Yujun 《《地质学报》英文版》1995,69(4):341-357
On the basis of exhaustive researches on the facies sequences and depositlonal evolutionary process of various depositional systems, the genetic stratigraphic framework of the extensional rifted oceanic basin, which has undergone strong structural destruction, has been reconstructed by means of dynamic genetic stratigraphic analysis. Five depositional episodes have been distinguished from various isochronous stratigraphic boundaries and stratigraphic sequences with the three-dimensional structure of each depositional episode analysed in detail. The tectonic paleogeographic environment corresponding to different stages of each depositional episode has been reconstructed for individual depositional system tracts. And the evolution history of this rifted basin has been divided into four stages' initial rifting and oceanization of continental crust, stretching and spreading of the basin, subduction and basin differentiation, and convergence and collision. A NNE-trending intracontinental soft collision sutur 相似文献
996.
可变网格的有限单元分析在边坡稳定计算中的应用 总被引:3,自引:0,他引:3
本文在非线性有限单元法的基础上,引进八节点的狭长单元来描述边坡中的滑动面,同时对于有限元单元网格可调节点坐标进行变更形成新的网格,于是利用原有基本网格架,通过多次有限元分析求出边坡中可能滑动面的稳定系数曲线K=f(),并进而确定最危险的滑动面,在此基础上开展一系列稳定分析工作。 相似文献
997.
Naoki Niwa Takuji Kobori Motoichi Takahashi Tomohiko Hatada Haruhiko Kurino Jun Tagami 《地震工程与结构动力学》1995,24(5):655-671
This paper describes a feasibility study on a high-damping device (HiDAM) installed in a building structure by way of a bracing mechanism. A seismic response analysis with respect to a high-rise building approximately 100 m high is reported. Proper adjustment of the damping coefficient of the HiDAM (oil damper) provided an over all damping factor of about 10–20 per cent to the building structure, and reductions in the response, deformation and shear forces were verified analytically. This paper reports also the performance confirmation tests conducted on a model device of the HiDAM which satisfied the specifications determined from the analytical results. The test results demonstrate the feasibility of the HiDAM and the possibility of utilizing it in high-rise buildings. 相似文献
998.
Field survey of the 1994 Mindoro Island,Philippines tsunami 总被引:2,自引:0,他引:2
Fumihiko Imamura Costas E. Synolakis Edison Gica Vasily Titov Eddie Listanco Ho Jun Lee 《Pure and Applied Geophysics》1995,144(3-4):875-890
This is a report of the field survey of the November 15, 1994 Mindoro Island, Philippines, tsunami generated by an earthquake (M=7.0) with a strike-slip motion. We will report runup heights from 54 locations on Luzon, Mindoro and other smaller islands in the Cape Verde passage between Mindoro and Luzon. Most of the damage was concentrated along the northern coast of Mindoro. Runup height distribution ranged 3–4 m at the most severely damaged areas and 2–4 in neighboring areas. The tsunami-affected area was limited to within 10 km of the epicenter. The largest recorded runup value of 7.3 m was measured on the southwestern coast of Baco Island while a runup of 6.1 m was detected on its northern coastline. The earthquake and tsunami killed 62 people, injured 248 and destroyed 800 houses. As observed in other recent tsunami disasters, most of the casualties were children. Nearly all eyewitnesses interviewed described the first wave as a leading-depression wave. Eyewitnesses reported that the main direction of tsunami propagation was SW in Subaang Bay, SE in Wawa and Calapan, NE on Baco Island and N on Verde Island, suggesting that the tsunami source area was in the southern Pass of Verde Island and that the wave propagated rapidly in all directions. The fault plane extended offshore to the N of Mindoro Island, with its rupture originating S of Verde Island and propagating almost directly south to the inland of Mindoro, thereby accounting for the relatively limited damage area observed on the N of Mindoro. 相似文献
999.
地磁偏角实时自动修正技术在油田定向钻井中的应用 总被引:2,自引:1,他引:2
在油田定向钻井的磁导向定位系统中,地磁偏角校正是一个不可缺少的基本要素,同时在磁偏角校正值精度直接影响定向井的导向定位精度。因此,作者提出了提高地磁偏角校正值精度的方法,并试图将地磁偏角实时自动修正技术引入我国油田定向钻井领域。 相似文献
1000.
The eigen oscillation of a fluid sphere embedded in an infinite elastic medium is analyzed to understand the source mechanism of volcanic tremor that vibrates nearly monotonically and attenuates slowly. The dimensionless eigen frequencies of the sinusoidal oscillation are calculated in a complex form with the attenuation factor in its imaginary part for various combinations of the three parameters: the contrasts of P-wave velocity, density and rigidity between the fluid and the country rock. Eigen oscillations consist of a high attenuation mode with a rapidly decaying pulsive wave at a low frequency and infinite number of regular modes with slowly decaying vibrations. For regular modes, the frequency of oscillation obtained from the real part of an eigen value is distributed in approximately regular intervals while the attenuation factor from the imaginary part is almost constant independent of the mode. Each eigen frequency of regular and high attenuation modes is degenerated with two independent eigen functions describing different distributions of displacement, velocity and stress. The theory is applied to harmonic volcanic tremor observed at Kusatsu-Shirane Volcano, central Japan. Observed spectral peaks of the tremor are explained by the eigen frequencies and attenuation factors of several lowest regular modes if the spherical fluid oscillator has a radius of dozens of meters and a P-wave velocity of about several hundred meters per second. 相似文献