Taking Adaohai Coal Mine as the example, underground pressure appearance laws of fully mechanized top coal slice caving on high-dipping and thick coal seams. Through site visit, theoretical analysis and discrete eleme...Taking Adaohai Coal Mine as the example, underground pressure appearance laws of fully mechanized top coal slice caving on high-dipping and thick coal seams. Through site visit, theoretical analysis and discrete element calculation, the research shows that, as the mining deepens, underground stress of lower sublevels is more obvious and higher than that of upper sublevels and is higher in the air return roadway than that in the air intake roadway in the area that is near to the top coal. Because the top coal is thick and gangue is caved above the support, underground pressure to the working face is relatively gentle. Immediate roof will mainly fall down along the floor. Main roof and the rock bed above the main roof will move to the mined out area along the fault in the early stage and then fall down with the mined out area later. In addition, roof pressure mainly periodically appears in two directions along the trend and the dip.展开更多
According to the requirements for the beam collimation system of the rapid cycling synchrotron(RCS)of China Spallation Neutron Source(CSNS),the main structure of a scraper of primary collimator is made by W/Cu brazing...According to the requirements for the beam collimation system of the rapid cycling synchrotron(RCS)of China Spallation Neutron Source(CSNS),the main structure of a scraper of primary collimator is made by W/Cu brazing,in which the thickness of tungsten slice is 0.17 mm.In order to get the best mechanical properties,the brazing temperature is suggested to be controlled under the recrystallization temperature of tungsten,while the recrystallization temperature is affected directly by the thickness of tungsten.Because of little research and application on the brazing of thin tungsten slice of 0.17 mm and copper,tensile tests are done to get the mechanical properties of tungsten slices which experience different brazing temperatures.In keeping the inner relationships between the mechanical properties and temperature,another experiment is done by using SEM to scan the microstructures including the size and distribution of crystals.Finally we determine the recrystallization temperature of tungsten slice of 0.17 mm,and get the best parameters of W/Cu brazing for scrapers of primary collimator in CSNS/RCS.展开更多
基金Supported by the Scientific Research Business of China University of Mining ＆ Technology （Beijing） （2009QZ04） the National Natural Science Foundation of China （50974123）
文摘Taking Adaohai Coal Mine as the example, underground pressure appearance laws of fully mechanized top coal slice caving on high-dipping and thick coal seams. Through site visit, theoretical analysis and discrete element calculation, the research shows that, as the mining deepens, underground stress of lower sublevels is more obvious and higher than that of upper sublevels and is higher in the air return roadway than that in the air intake roadway in the area that is near to the top coal. Because the top coal is thick and gangue is caved above the support, underground pressure to the working face is relatively gentle. Immediate roof will mainly fall down along the floor. Main roof and the rock bed above the main roof will move to the mined out area along the fault in the early stage and then fall down with the mined out area later. In addition, roof pressure mainly periodically appears in two directions along the trend and the dip.
基金supported by China Spallation Neutron Source(CSNS)
文摘According to the requirements for the beam collimation system of the rapid cycling synchrotron(RCS)of China Spallation Neutron Source(CSNS),the main structure of a scraper of primary collimator is made by W/Cu brazing,in which the thickness of tungsten slice is 0.17 mm.In order to get the best mechanical properties,the brazing temperature is suggested to be controlled under the recrystallization temperature of tungsten,while the recrystallization temperature is affected directly by the thickness of tungsten.Because of little research and application on the brazing of thin tungsten slice of 0.17 mm and copper,tensile tests are done to get the mechanical properties of tungsten slices which experience different brazing temperatures.In keeping the inner relationships between the mechanical properties and temperature,another experiment is done by using SEM to scan the microstructures including the size and distribution of crystals.Finally we determine the recrystallization temperature of tungsten slice of 0.17 mm,and get the best parameters of W/Cu brazing for scrapers of primary collimator in CSNS/RCS.
