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171.
172.
中国硼矿主要矿集区及其资源潜力探讨 总被引:5,自引:0,他引:5
在分析中国硼矿床成因类型的基础上,将中国硼矿床划分沉积变质、现代盐湖沉积、矽卡岩和地下卤水4个矿床类型8个矿床式,最为重要的矿床类型为沉积变质型硼矿和现代盐湖型沉积硼矿床。在硼矿成矿区带划分方案的基础上,综合成矿规律、地质构造背景等因素划分出辽-吉沉积变质型、川-鄂地下卤水型、湘-桂矽卡岩型、西藏现代盐湖型和青海柴达木现代盐湖型5个硼矿矿集区。其中辽-吉老矿区深部和外围、川鄂区的地下卤水及盐湖硼矿的综合利用等方向尚有较大潜力。 相似文献
173.
GPU accelerated marine data visualization method 总被引:1,自引:0,他引:1
The study of marine data visualization is of great value. Marine data, due to its large scale, random variation and multiresolution in nature, are hard to be visualized and analyzed. Nowadays, constructing an ocean model and visualizing model results have become some of the most important research topics of ‘Digital Ocean'. In this paper, a spherical ray casting method is developed to improve the traditional ray-casting algorithm and to make efficient use of GPUs. Aiming at the ocean current data, a 3D view-dependent line integral convolution method is used, in which the spatial frequency is adapted according to the distance from a camera. The study is based on a 3D virtual reality and visualization engine, namely the VV-Ocean. Some interactive operations are also provided to highlight the interesting structures and the characteristics of volumetric data. Finally, the marine data gathered in the East China Sea are displayed and analyzed. The results show that the method meets the requirements of real-time and interactive rendering. 相似文献
174.
To retrieve wind field from SAR images, the development for surface wind field retrieval from SAR images based on the improvement of new inversion model is present. Geophysical Model Functions(GMFs) have been widely applied for wind field retrieval from SAR images. Among them CMOD4 has a good performance under low and moderate wind conditions. Although CMOD5 is developed recently with a more fundamental basis, it has ambiguity of wind speed and a shape gradient of normalized radar cross section under low wind speed condition. This study proposes a method of wind field retrieval from SAR image by combining CMOD5 and CMOD4 Five VV-polarisation RADARSAT2 SAR images are implemented for validation and the retrieval results by a combination method(CMOD5 and CMOD4) together with CMOD4 GMF are compared with QuikSCAT wind data. The root-mean-square error(RMSE) of wind speed is 0.75 m s-1 with correlation coefficient 0.84 using the combination method and the RMSE of wind speed is 1.01 m s-1 with correlation coefficient 0.72 using CMOD4 GMF alone for those cases. The proposed method can be applied to SAR image for avoiding the internal defect in CMOD5 under low wind speed condition. 相似文献
175.
破碎波对近海海岸地形以及海岸建筑物影响强烈,通过物理模型实验对孤立波、规则波作用下破碎带的床面形态以及孔隙水压力进行分析。破碎波冲击海床,破碎处床面上形成沙坝和沙坑,与规则波相比,孤立波破碎时对床面的冲刷更加剧烈,床面形成的沙坝和沙坑尺度更大,且土体内孔隙水压力幅值也较大。同时研究了波面变化对孔隙水压力的影响,发现波面变化历时曲线与孔隙水压力历时曲线相似,与孔隙水压力梯度历时曲线更为相似,说明波面变化更能反映海床内部孔隙水压力梯度的变化。通过探讨波浪与海床之间相互耦合作用,发现破碎带地形变化使得波浪出现不同破碎类型,分析得出卷破波比崩破波作用下孔隙水压力幅值大。 相似文献
176.
泰国湾区域经历了前裂谷期、裂谷期、裂后期的构造演化阶段,形成了多个裂谷盆地。泰国湾区域东北部在渐新世经历了一次明显构造反转,较泰国湾区域大部分地区强烈。通过对比区内钻井,结合地震解释,对该区的沉积特征和构造演化进行了分析,认为这次反转构造导致了反转构造带上构造、沉积特征与邻区有较大的不同。由于这次反转构造,泰国湾东北部在新层系发育新类型的油气系统,即深部的始新统油气系统:烃源岩为中始新统湖相泥岩,储层为上始新统-渐新统三角洲相砂岩,盖层为下中新统三角洲前缘相泥岩和上中新统以上的海相泥岩。该油气成藏系统已被钻井钻遇油气显示,是本区有效油气成藏系统。 相似文献
177.
178.
J. Deng Y. Shao N. Gao Y. Deng C. Tan S. Zhou 《International Journal of Environmental Science and Technology》2014,11(4):881-890
Zero-valent iron (Fe0), as an alternative iron source, was evaluated to activate persulfate (PS) to degrade acetaminophen (APAP), a representative pharmaceutically active compound in water. Effects of key factors in the so-called Fe0/PS process, including Fe0 dosage, initial pH, temperatures and chelating agents, were studied. Under all the conditions tested, the APAP degradation followed a pseudo-first-order kinetics pattern. The degradation efficiency of APAP was highest when the Fe0 to PS molar ratio increased to 1:1, and the degradation rate constant and removal were 23.19 × 10?3 min?1 and 93.19 %, respectively. Comparing with Fe2+, Fe0 served as an alternative iron source that can gradually release Fe2+ into water, thereby consistently activating PS to produce sulfate radicals. The Fe0/PS system was effective in a broader pH range from 3 to 8.5. Heat could facilitate production of sulfate radicals and enhance the APAP degradation in the Fe0/PS system. High reaction temperature also improved the Fe2+/PS oxidation of APAP. Finally, sodium citrate (a chelating agent) at an appropriate concentration could improve the APAP degradation rate in the Fe2+/PS and Fe0/PS system. The optimal molar ratio of Fe0 to citrate depended on solution pH. Our results demonstrated that Fe0 was an alternative iron source to activate PS to degrade APAP in water. 相似文献
179.
Experimental study of poromechanical behavior of saturated claystone under triaxial compression 总被引:1,自引:1,他引:0
This paper presents experimental results of drained and undrained triaxial compression tests of saturated Meuse–Haute/Marne claystone. The emphasis is to study the evolution of pore pressure with growth of microcracks and the effect of pore pressure on mechanical behavior. Basic mechanical responses are first investigated through drained triaxial compression tests, showing nonlinear stress strain relations, volumetric dilatancy and pressure sensitivity. In undrained triaxial compression tests, the pore pressure exhibits a transition from increase to decrease due to the transition from volumetric compressibility to dilatancy caused by the growth of microcracks. The failure surfaces, determined by total stress and Terzaghi’s effective stress under undrained condition, are compared with the one under drained condition. 相似文献
180.
Experimental Researches on Hydro-Mechanical Properties of Altered Rock Under Confining Pressures 总被引:1,自引:0,他引:1
Altered rock, as the abutment materials of Xiaowan Hydropower Station in China, is a kind of geological defective rock mass. It is loosely structured and its strength is low, with some development of pores and cavities. Research on the hydro-mechanical coupling of the altered rock are of important significance to hydropower projects. In this study, the advanced fully automatic triaxial fluid flow-rheological test servo system is employed to study the hydro-mechanical coupling characteristics of the altered rock, and the water pressures and confining pressures in the laboratory tests are set to simulate the conditions of excavation and impoundment of Xiaowan Hydropower Station. Based on the test results, the stress–strain laws of the rock specimens under the effect of complete hydro-mechanical coupling, as well as the lateral strain and volumetric strain characteristics, are studied. The fluid flow laws of the rock specimens and the effects of the confining pressures on the fluid flow are analyzed. The fluid flow failure characteristic under the effect of the complete hydro-mechanical coupling is discussed. The research achievements show that with the change of the stress states, the permeability of the rock also changes, and the permeability evolution shows the phase characteristic during the process of stress and strain. The impacts of the confining pressures on the strength and deformation and permeability of the altered rock are obvious. The failure behaviours of the rock specimens under the effect of coupling relates to the confining pressures, including two kinds of splitting failure and shear failure. The fluid flow failure characteristic of the rock specimens depend upon the initiation, growth and coalesce of micro-cracks, heterogeneity, confining pressures and properties of the rock. 相似文献