Abrupt uplift of Tibetan Plateau at the end of early Pleistocene and Australasian impact event     

REN Shoumai  LIU Yongjiang  GE Xiaohong . Strategic Research Center of Oil & Gas Resources  Ministry of L  & Resources  Beijing  China . College of Earth Sciences  Jilin University  Changchun  China 《东北亚地学研究》2009,(3):145-155

The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic-Cenozoic compressional structure due to the subduction of the Indian Plate beneath the Asian continent. This event definitively effected the formation of basin-mountain relief, Cenozoic basin deformation, large scale aridity and desertification of western China. The Australasian meteorites impact event happened ca. 0.8 Ma ago, located in the triangle area of the Indian Ocean ridge （20°S/67°E）. The impact may have resulted in an acceleration of speeding of the Indian Ocean ridge pushing the Indian Plate to subduct rapidly northward. Thus, the impact event can give reasonable explanation for the dynamic background of the latest rapid uplift of the Tibetan Plateau and the continental deformation of western China and even of the Middle Asia.  相似文献   

Variation characteristics of temperature and moisture content of seasonal frozen soil during freezing process in Changchun,China     

WANG Qing  FAN Jianhua  FANG Ming  ZHANG Li .College of Construction Engineering  Jilin University  Changchun  China .China Northeast Municipal Engineering Design  Research Institute  Changchun  China 《东北亚地学研究》2009,12(1):13-16

In China, seasonal frozen soil is widely distributed. The freezing damage of subgrade soil in Jilin Province has been one of major engineering geological problems troubling the safety of road, in which some common damage phenomena, such as frost heave, subsidence deformation and frost boiling, are all caused by water translocation. Aiming at the phenomenon, the changes of moisture content of seasonal frozen soil in Changchun City are mainly studied by long-term field observation and indoor testing of physical properties under different conditions, and then the variation characteristics of moisture content in soil under different compactness and temperature conditions are realized. The results show that the increasing section of moisture content and negative temperature section all lie in O. 0 - 1.0 m of subgrade. Both lowest air and earth temperature occur in January to February, and the most negative temperature ranges from -7℃ to -10℃.  相似文献   

Spatial and temporal variations of Synechococcus and picoeukaryotes in the Taiwan Strait,China     

黄邦钦  林学举  洪华生 《中国海洋湖沼学报》2009,27(1)

The size-fractionated phytoplankton biomass, and the spatial and temporal variations in abundance of Synechococcus (SYN) and picoeukaryotes (PEUK) were measured in the Taiwan Strait during three cruises (August 1997, February-March 1998, and August 1998). The results show that picophytoplankton and nanophytoplankton dominate the phytoplankton biomass, in average of 38% and 40%, respectively. SYN and PEUK varied over time in abundance and carbon biomass, greater in summer than in winter, in range of (7.70–20...  相似文献   

Application of ultrasonic CT method in nondestructive detection of interior defects in large scale concrete structural member of bridge     

Xiaopei ZHANG  Jianhui QIU  Jianjun NIU  Lizhi DU  Xuege WANG .College of Construction Engineering  Jilin university  Changchun  China.China Northeast Municipal Engineering Design  Research Institute  Changchun  China 《东北亚地学研究》2008,11(4):218-221

The ultrasonic computed tomography （USCT） method is derived from the basic principles of X-ray section scanning. This method records the arriving times of ultrasonic wave between the probes and the sources to ealculate the elastic wave velocity values in the section using the arrival times. Through analyzed the distribution Of elastic wave velocity in aim area, the information of the strength and the homogeneity of the investigated zone could be got indirectly. The authors introduced the operational principle of USCT and a practical case of using this method to detect the interior defects in large scale concrete structural member. Compared with other exploration methods, this method is more efficient and accurate.  相似文献   

Analysis of groundwater recoverable resource by numerical method in Linfen Basin of Shanxi, North China     

Liping BAI    Yeyao WANG  Jinsheng WANG . Chinese Research Academy of Environmental Sciences  Beijing  China. College of Water Sciences  Beijing Normal University  Beijing  China 《东北亚地学研究》2008,11(3):168-173

Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical model was calibrated by observed groundwater level from February to December in 2 000. Based on the calibrated model, the groundwater recoverable resource is calculated. The simulation result shows that under the given value of the groundwater recoverable resource, the groundwater level would decrease significantly in the first 1 000 days, while the water level would drop slowly in 1 000 to 2 000 days, and the water level change tend to be stable after 2000 days.  相似文献   

Structural feature and tectonic evolution of Awati——Bachu area in Tarim Basin     

Zhihong LIU  Defeng ZHU  Junyi GAO  Xiangmei WUDongcheng LIN  Liguo ZHANG . Collage of Earth Sciences  Jilin University  Changchun  China. Exploration  Development Research Institute of Daqing Oilfield Company Ltd.  Daqing  Heilongjiang  China 《东北亚地学研究》2008,11(1):19-24

The research area is situated in the western part of Tarim basin, which includes Awati depression and Bachu uplifted block. It underwent three times processes of compression in a large scale and a near term extension since Cambrian. The first compression occurred during Middle Cambrian to Devonian, which formed fault band folds in NW axial direction. They were ＂under-water uplift＂ and distributed all over the research area. The second compression occurred in Late Permian and formed fault band folds and a few fault propagation folds in NS axial direction. They are developed near Tumuxiuke fault belt and the northern research area. The western anticline is bigger than the eastern one in extent and size. The third compression occurred during Palaeogene to Quaternary and formed tumuxiuke fault belt and fault propagation folds in NW direction. They are distributed over the south part of the research area. Tumuxiuke fault belt is a big scale dextral reversed strike-slip fault belt; it transformed or destroyed the fold structure of the research area. A short-term extension occurred during Early Permian. Tarim Basin is in the rift forming stage of craton, and there exist widespread basic vol- canic rocks, basic intrusive bodies and dikes.  相似文献   

Application of TSD tunnel seismic prediction system in karst area     

Lizhi DU  Xiaopei ZHANG  Jianjun NIU  Xuege WANG .College of Construction Engineering  Jilin University  Changchun  China.China Northeast Municipal Engineering Design  Research Institute  Changchun  China 《东北亚地学研究》2008,11(4):246-250

TSD is one of the classical methods of tunnel seismic prediction based on higher accuracy multi-wave multi-component seismology. The working principle of the TSD and an application example of the TSD on tunnel prediction in Chongqing are introduced in this paper. This system has two ports for speed signal and acceleration signal, and the equipment is more portable and easy to use. According to the application results we can conclude that the TSD prediction system is accurate and it has the wide application prospect in tunnel seismic detection.  相似文献   

ON THE DISCORDANT URBAN DEVELOPMENT IN XI’AN CITY     

康慕谊  江源 《中国地理科学(英文版)》1999,(2)

ＵｒｂａｎｉｚａｔｉｏｎｉｓａｗｏｒｌｄｗｉｄｅｔｒｅｎｄｏｆｄｅｖｅｌｏｐｍｅｎｔａｎｄｏｎｅｏｆｔｈｅｍａｉｎｃｏｎｔｅｎｔｓｏｆｅｃｏｎｏｍｉｃａｎｄｓｏｃｉａｌｄｅｖｅｌｏｐｍｅｎｔｓｔｏｗａｒｄＣｈｉｎａ’ｓｍｏｄｅｒｎｉｚａｔｉｏｎ．Ｉ...  相似文献   

Fatigue Behaviour of Tubular Joints Made of China-Made Platform Steel     

Wang Gnanghai  Chen Bozhen Senior Research Engineer  China Ship Scientific Research Center 《中国海洋工程》1992,(1)

In China, a nationwide research program on fatigue behaviour of tubular joints made of China-made platform steel was carried out from 1983 to 1990, which was set by the Tubular Joint Research Committee for Offshore Structures (TJCOS) of China. This paper gives an outline of the basic properties of the China-made platform steel and fatigue test of tubular joints, including test specimens, test particulars and test results. A p-S-N curve based on the test results was established which reveals that the fatigue strength of tubular joints is fairly good. The thickness effect and effect of corrosion on fatigue strength in sea water are briefly discussed.  相似文献   

Effects of salinity, light and temperature on growth rates of two species of Gracilaria (Rhodophyta)     

徐永健  韦玮  方建光 《中国海洋湖沼学报》2009,27(2)

Effects of temperature, salinity and light intensity on growth rates of Gracilaria lichenoides and G tenuistipitata var. liui Zhang et Xia were tested. Eight to ten levels of each factor were first tested separately. The best growth rate was obtained under the conditions of 32～C, 30 and 240 μmol/(m2·s) for G. lichenoides, and 24℃, 20 and 200 μmol/(m2.s) for G. tenuistipitata, respectively. Then a uniform design was used to evaluate the optimal combinations of the three factors. The best conditions for the highest daily specific growth rates (% increase in wet weight) are determined to be 31.30℃, 32.10, and 287.23 μmol/(m2·s) for G. lichenoides (16.26%/d), and 25.38℃, 21.10, and 229.07 μmol/(m2·s) for G. tenuistipitata (14.83%/d), respectively.  相似文献