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81.
82.
采自阴山东段先寒武变质岩的全岩样品给出四个等时线年龄。下部集宁群为2497±124Ma;上部乌拉山群为2367±127Ma;上部二道洼群给出两个年龄:2067±39Ma和325±16Ma。据此认为,2.5Ga前发生了麻粒岩化;2.35Ga前发生混合岩化;2.0Ga和0.33Ga前有变质事件叠加。 相似文献
83.
84.
Hydraulic and numerical study on the generation of a subaqueous landslide-induced tsunami along the coast 总被引:1,自引:0,他引:1
Yoshinori Shigihara Daichi Goto Fumihiko Imamura Yuichi Kitamura Takayuki Matsubara Kazuaki Takaoka Kazuhiko Ban 《Natural Hazards》2006,39(2):159-177
By carrying out the hydraulic experiments in a one-dimensional open channel and two-dimensional basin, we clarified the process
of how a landslide on a uniform slope causes the generation of a tsunami. The effect of the interactive force that occurs
between the debris flow layer and the tsunami is significant in the generation of a tsunami. The continuous flow of the debris
into the water makes the wave period of the tsunami short. The present experiments apply numerical simulation using the two-layer
model with shear stress models on the bottom and interface, and the results are compared. The simulated debris flow shows
good agreement with the measured results and ensures the rushing process into the water. We propose that the model use a Manning
coefficient of 0.01 for the smooth slope and 0.015 for the rough slope, and a horizontal viscosity of 0.01 m2/s for the landslide; an interactive force of 0.2 for each layer is recommended. The dispersion effect should be included
in the numerical model for the propagation from the shore. 相似文献
85.
Jun Chen Lijun Chen Fei Chen Yifang Ban Songnian Li Gang Han Xiaohua Tong Chuang Liu Vanya Stamenova Stefan Stamenov 《地球空间信息科学学报》2021,24(1):134-144
30-m Global Land Cover(GLC)data products permit the detection of land cover changes at the scale of most human land activities,and are therefore used as fundamental information for sustainable development,environmental change studies,and many other societal benefit areas.In the past few years,increasing efforts have been devoted to the accuracy assessment of GlobeLand30 and other finer-resolution GLC data products.However,most of them were conducted either within a limited percentage of map sheets selected from a global scale or in some individual countries(areas),and there are still many areas where the uncertainty of 30-m resolution GLC data products remains to be validated and documented.In order to promote a comprehensive and collaborative validation of 30-m GLC data products,the GEO Global Land Cover Community Activity had organized a project from 2015 to 2017,to examine and explore its major problems,including the lack of international agreed validation guidelines and on-line tools for facilitating collaborative validation activities.With the joint effort of experts and users from 30 GEO member countries or participating organizations,a technical specification for 30-m GLC validation was developed based on the findings and experiences.An on-line validation tool,GLCVal,was developed by integrating land cover validation procedures with the service computing technologies.About 20 countries(regions)have completed the accuracy assess-ment of GlobeLand30 for their territories with the guidance of the technical specification and the support of GLCVal. 相似文献
86.
Ban Yuxin Fu Xiang Xie Qiang Cui Jianfeng Xu Hong 《Geotechnical and Geological Engineering》2021,39(5):3655-3667
Geotechnical and Geological Engineering - Coal seam mining is one of the most widely participated engineering activities in China. This study examined the failure process induced by underground... 相似文献
87.
安顺市畜禽养殖碳排放时空差异研究 总被引:1,自引:0,他引:1
畜禽养殖是农业碳源之一。根据安顺市畜禽数量,估算2001—2015年安顺市畜禽碳排放量。从畜禽碳排放结构、碳排放变异系数、碳排放密度、碳排放经济强度4个方面对其进行分析。研究结果显示:(1)安顺市2001—2006年的畜禽碳排放量连续增长,由86.91万t增长到113.06万t,2007年下降到84.31万t;2007—2010年缓慢增长;2011—2013年相对平稳;2014—2015年又增长。(2)畜禽碳排放主要来自牛和猪,牛年均碳排放量为70.70万t。(3)安顺市2003—2007年各区县畜禽碳排放绝对差异呈现扩大趋势,2008—2014年差异性呈现减小趋势。(4)西秀区的畜禽碳排放密度最高,平坝县最低;镇宁县的畜禽碳排放经济强度最高;紫云县次之;关岭县最低。安顺市政府部门应该研制并推广畜禽养殖温室气体减排技术,降低畜禽养殖碳排放量。 相似文献
88.
CHEN Jing’an WANG Fushun WAN Guojiang TANG Degui David Dian ZHANG HUNAG Ronggui LI Jian XIAO Tangfu 《《地质学报》英文版》2008,82(5):975-981
The correlation between the δ^13C and δ^13C-δ^18O in primary carbonates is affected by several factors such as hydrological balance, total CO2 concentrations, climatic condition and lake productivity. The influence of these factors on the δ^13C-δ^18O correlation may be different on different time scales. In this paper, two different-type lakes in southwestern China, Lake Erhai and Lake Chenghai, are selected to investigate the influence of climatic pattern on the δ^13C-δ^18O correlation and to evaluate the reliability of the δ^13C-δ^18O covariance as an indicator of hydrological closure. The results show that there exists good correlation between the δ^13C and δ^18O in Lake Erhai (overflowing open lake) and in Lake Chenghai (closed lake). This suggests that the δ^13C-δ^18O covariance may be not an effective indicator of hydrological closure for lakes, especially on short time scales. On the one hand, a hydrologically open lake may display covariant δ^13C and δ^18O as a result of climatic influence. The particular alternate warm-dry and cold-wet climatic pattern in southwestern China may be the principal cause of the δ^13C-δ^18O covariance in Lake Erhai and Lake Chenghai. On the other hand, a hydrologically closed lake unnecessarily displays covariant trends between δ^13C and δ^18O because of the buffering effect of high CO2 concentration on the δ^13C shift in hyper-alkaline lakes. We should be prudent when we use the covariance between δ^13C and δ^18O to judge the hydrological closure of lake. 相似文献
89.
武汉某深基坑锚式连锁灌注排桩变形的有限元分析 总被引:1,自引:0,他引:1
以武汉某深基坑为例,采用有限单元数值模拟方法,研究基坑开挖深度,锚杆预应力,桩体厚度,桩体嵌入深度的变化与其锚式连锁灌注排桩支护结构水平变形位移的关系。 相似文献
90.
川中红色砂泥岩岩石力学特性研究 总被引:9,自引:0,他引:9
对川中白垩系、侏罗系的泥岩、砂岩、泥质粉砂岩的抗压强度进行统计分析 ,得出红层岩石作为地基时抗压强度的范围值供设计参考 ,对泥岩、砂岩的其他力学性质进行了评价。 相似文献