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CRESDA Successfully Processed the First Track Data of GF-3
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作者 China Center For Resources Satellite Data and Application 《Aerospace China》 2016年第3期51-53,共3页
The first images obtained from Gaofen-3(GF-3),China’s first C-band high-resolution Synthetic Aperture Radar(SAR)satellite with a resolution of one meter in spatial diameter were published on August 25.This satell... The first images obtained from Gaofen-3(GF-3),China’s first C-band high-resolution Synthetic Aperture Radar(SAR)satellite with a resolution of one meter in spatial diameter were published on August 25.This satellite undertakes an important task with its all-day,all-weather observation capability as part of the China High-resolution Earth Observation System(CHEOS).With 12 imaging modes, 展开更多
关键词 weather Observation picture Figure covering minutes processed launch completed texture
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EXPERIMENTAL RESEARCH ON THE ULTRASONIC TECHNIQUE AND ITS APPLICATION IN STUDYING ROCK PROPERTIES 被引量:1
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作者 孙永联 周楚良 +1 位作者 余学东 姜耀东 《Journal of China University of Mining and Technology》 1992年第1期44-55,共12页
The experimental installation and measurement system of ultrasonic wave property in rocks during complete stress-strain process were established and perfected. The interrelations between ultrasonic wave property of mu... The experimental installation and measurement system of ultrasonic wave property in rocks during complete stress-strain process were established and perfected. The interrelations between ultrasonic wave property of muds tone, sands tone and limestone specimens during complete stress-strain process and their mechanic property were investigated. A new type of device for the observation of surrounding rock stability-borehole ultrasonic device with completely dry coupling was developed to get better coupling and more accurate measurement data comparing with those of water coupling situation. Preliminary study on the application of ultrasonic measurement technique at belt conveyor roadway of north wing in Baodian Coal Mine (Shandong province) was conducted. Based on the interrelations between the complete stress-strain properties of specimens and their wave properties, the structural properties of surrounding rocks, the range of yield zones, and the change of stresses within surrounding rocks when a longwall face was across over the roadway were analyzed.Therefore,a new and feasible way was found for the research on the deformation law of surrounding rock of roadway and rational selection of support parameters. 展开更多
关键词 ultrasonic wave wave-spectrum analysis complete stress-strain process dry coupling
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A multifunctional shear apparatus for rocks subjected to true triaxial stress and high temperature in real-time
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作者 Jun Zhao Xia-Ting Feng +2 位作者 Jia-Rong Wang Liang Hu Yue Guo 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2024年第9期3524-3543,共20页
Deep engineering disasters,such as rockbursts and collapses,are more related to the shear slip of rock joints.A novel multifunctional device was developed to study the shear failure mechanism in rocks.Using this devic... Deep engineering disasters,such as rockbursts and collapses,are more related to the shear slip of rock joints.A novel multifunctional device was developed to study the shear failure mechanism in rocks.Using this device,the complete shearedeformation process and long-term shear creep tests could be performed on rocks under constant normal stiffness(CNS)or constant normal loading(CNL)conditions in real-time at high temperature and true-triaxial stress.During the research and development process,five key technologies were successfully broken through:(1)the ability to perform true-triaxial compressioneshear loading tests on rock samples with high stiffness;(2)a shear box with ultra-low friction throughout the entire stress space of the rock sample during loading;(3)a control system capable of maintaining high stress for a long time and responding rapidly to the brittle fracture of a rock sample as well;(4)a refined ability to measure the volumetric deformation of rock samples subjected to true triaxial shearing;and(5)a heating system capable of maintaining uniform heating of the rock sample over a long time.By developing these technologies,loading under high true triaxial stress conditions was realized.The apparatus has a maximum normal stiffness of 1000 GPa/m and a maximum operating temperature of 300C.The differences in the surface temperature of the sample are constant to within5C.Five types of true triaxial shear tests were conducted on homogeneous sandstone to verify that the apparatus has good performance and reliability.The results show that temperature,lateral stress,normal stress and time influence the shear deformation,failure mode and strength of the sandstone.The novel apparatus can be reliably used to conduct true-triaxial shear tests on rocks subjected to high temperatures and stress. 展开更多
关键词 True-triaxial shear apparatus Rocks Complete shear stressedeformation process Creep Real-time high-temperature
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