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991.
As a pioneer worker in almost every phase of the Chinese geology,the late Dr. V. K. Ting was also a pioneer and enthusiastic worker inthe geology of the Western Hills. It was due to his noble effort andsupervision that the first systematic investigation of 1916 was carried out 相似文献
992.
陈建民局长指出,党中央、国务院高度重视防震减灾工作。胡锦涛总书记在全国抗震救灾总结表彰大会和2008年两院院士大会上强调指出,“提高防灾减灾能力,是保护人民生命财产安全、保卫改革开放和社会主义现代化建设成果的必然要求,必须把防灾减灾工作作为关系经济社会发展全局的一项重大工作进一步抓紧抓好。要做好自然灾害规律研究、加强自然灾害监测和预警能力建设等六个方面的工作”。 相似文献
993.
A 2-D global chemistry-transport model is set up in this paper.The model simulates the atmospheric ozone distributions well with specified dynamical conditions.The analysis of ozone variation mechanism shows that ozone is chemically in quasi-equilibrium except for the polar night region where the variation of ozone concentration is under the control of dynamical processes,that the oxygen atoms which produce ozone are mainly provided by the photolysis of O2 in the upper stratosphere and by the photolysis of NO2 in the lower stratosphere and the troposphere.and that the ozone is destroyed mainly by NOx:the reactions between NOx and O3 and the odd oxygen cycle contribute 80% to more than 90% of the ozone destruction. 相似文献
994.
目的:探讨螺旋CT双期或多期扫描技术对肝内小于3cm或CT表现不典型的肝小血瘤的诊断和鉴别诊断的意义。方法:采用双期或多期全肝和局部动态扫描。结果:直径小于3cm的肝小血管瘤增强表现复杂,呈多样化的影像。结论:肝小血管瘤的鉴别诊断的正确率与CT扫描技术密切相关,而观察延迟和扫描病灶密度的充盈程度尤为重要。 相似文献
995.
HUANG SiJing HUANG KeKe TONG HongPeng LIU LiHong SUN Wei & ZHONG QianQian State Key Lab of Oil Gas Reservoir Geology Exploitation 《中国科学:地球科学(英文版)》2010,(5)
The natural gas from the Triassic Feixianguan Formation of Northeast Sichuan Basin contains high H2S whereas relatively low CO2 concentrations and the CO2 display high δ13C values (ranging from -5.81‰ to 3.3‰ (PDB)). This seems to contradict the conventional wisdom that TSR should be a primary source of CO2 in natural gas from the Feixianguan Formation. In contrast, many authigenic calcite samples from these sites display very low δ13C values (ranging from -18.4‰ to -10.3‰ (PDB)). This suggests that the carbon from TSR source dominated the formation of calcite whereas the carbon from inorganic source came into CO2 in natural gas. In order to assess the origin of CO2 from these H2S-rich sites, we have calculated the relative contributions of organic and inorganic carbon sources to the CO2 and authigenic calcite. The organic carbon source possibly originated from TSR, whereas the inorganic one might be generated from marine carbonates dissolution. This calculation is based on the carbon isotopic compositions of CO2 and authigenic calcite as well as an isotopic mass balance. The results show that the contribution of organic carbon source to the CO2 is only 2%, whereas that to authigenic calcite is as high as 43% on average. Such results combined with thermodynamic evidence indicate that the isotopically light CO2 produced by TSR process may contribute to authigenic calcite precipitation during burial diagenesis. Distinguishable from Ordovician reservoir of Tarim Basin, Feixianguan reservoir of Northeast Sichuan Basin experienced rapid tectonic uplift due to Yanshanian movement after TSR occurred. Such tectonic event could induce temperature decrease and further promote carbonates dissolution. During these processes, secondary porosity has developed in Feixianguan carbonate reservoirs. Therefore, much attention should be paid to the structural highs in search of high quality carbonate reservoirs. 相似文献
996.
2010年青海玉树地震及震后青藏高原强震趋势分析 总被引:2,自引:0,他引:2
2010年4月14日青海玉树发生7.1级地震,这是该区历史上发生的最为强烈的地震。该地震属走滑型,地处青藏高原巴颜喀拉地块南边界,发震断裂为甘孜—玉树—风火山左旋走滑断裂,地震破裂主要向震中东南方向。该地震是巴颜喀拉地块与羌塘地块以不同速率向东运动,地块间的差异运动使其边界应力积累到一定程度引发破裂的结果。根据地震定标律估算的主震断层破裂参数和应力参数为:地震矩M0=1.78×1019N.m,矩震级MW=6.8,断层破裂面积S=468km2,断层错距D=1.4m,断层破裂长度L=37km,断层破裂宽度W=12.6km,剪应力τ0=16.8MPa,应力降Δσ=7.03MPa。历史地震分析表明,玉树7.1级地震是在世界8级以上地震、中国西部大三角7.8级以上地震、南北地震带7级以上地震和巴颜喀拉块体7级以上地震处于强烈活动背景下发生的。玉树地震后,青藏高原巴颜喀拉地块、羌塘地块及川滇菱形块体未来发生7级以上地震的危险性较大。 相似文献
997.
Geological disasters will happen in cold regions because of the effects of freeze-thaw cycles on rocks or soils, so studying the effects of these cycles on the mechanical characteristics and permeability properties of rocks is very important. In this study,red sandstone samples were frozen and thawed with 0,4, 8 and 12 cycles, each cycle including 12 h of freezing and 12 h of thawing. The P-wave velocities of these samples were measured, and the mechanical properties and evolution of the steady-state permeabilities were investigated in a series of uniaxial and triaxial compression tests. Experimental results show that, with the increasing of cyclic freeze-thaw times, the P-wave velocity of the red sandstone decreases. The number of freeze-thaw cycles has a significant influence on the uniaxial compressive strength, elastic modulus, cohesion, and angle of internal friction. The evolution of permeability of the rock samples after cycles of freeze-thaw in a complete stress-strain process under triaxial compression is closely related to the variation of the microstructure in the rock. There is a highly corresponding relationship between volumetric strain and permeability with axial strain in all stages of the stress-strain behaviour. 相似文献
998.
999.
莺—琼盆地1号断裂带含烃热流体活动初探 总被引:2,自引:1,他引:2
1号断裂带是莺-琼盆地油气勘探的重点地区之一,有机包裹体研究有助于追踪油气及热流体活动的痕迹,为油气运聚成藏提供地球化学依据,通过包裹体薄片镜下观察,均一温度和盐度测试,认为工区内发育五种类型的有机包裹体:(1)液态烃包裹体;(2)气流态烃包裹体;(3)气态烃包裹体;(4)含烃CO2包裹体;(5)烃子矿物包裹体,含烃CO2包裹体一般与气态烃共生,含烃子矿物包裹体既无液态烃共生又与气态烃共生,包裹体 相似文献
1000.