In order to release the tension and shear effect of the superjacent rock strata movement during excavation in coal mine,protect the surface borehole case from fracturing fast and make a good use of the surface borehol...In order to release the tension and shear effect of the superjacent rock strata movement during excavation in coal mine,protect the surface borehole case from fracturing fast and make a good use of the surface borehole during goaf methane drawing,a common synthesis tension deformation fracture model was set up based on the synthesis tension effect of the rock strata,and the deformation rule of the surface borehole case with time and space was researched.The results suggest that,to reduce the deformation the surface borehole should be built between the boundary of the stope and the knee of subsidence curve.At the same time,a 3DEC simulation model and an engineering example were carried out to examine the rules of theoretical model.The result suggests that the model and the rules accord to the test and have good building and protection engineering application values to the surface borehole.展开更多
A nitrogen phosphorus synergistic flame retardant DCMA was synthesized frOm N-methylol acrylamide （NMA） and Diethyl Chlorophosphate （DC）. The reaction time and reaction mechanism were determined by tracking the re...A nitrogen phosphorus synergistic flame retardant DCMA was synthesized frOm N-methylol acrylamide （NMA） and Diethyl Chlorophosphate （DC）. The reaction time and reaction mechanism were determined by tracking the reaction process using ultraviolet spectrum.The cotton cloth finished with DCMA, by rolling baking process, when the flame retardant concentration from 10% to 30%.the smoldering time decreased from 3S to 1 S, carbon length decreased from 10.5 to 6.3, limiting oxygen index by 31 increased to 36.4.the tensile breaking strength of cotton fabric decreased from 6.46MPa to 3.12MPa.展开更多
基金supports for this work provided by the NationalScience and Technology Major Project (No. 2011ZX05040-004)the National Great Research Foundation of China (No.2011CB201203)the National Natural Science Foundation of China(No. 50904034)
文摘In order to release the tension and shear effect of the superjacent rock strata movement during excavation in coal mine,protect the surface borehole case from fracturing fast and make a good use of the surface borehole during goaf methane drawing,a common synthesis tension deformation fracture model was set up based on the synthesis tension effect of the rock strata,and the deformation rule of the surface borehole case with time and space was researched.The results suggest that,to reduce the deformation the surface borehole should be built between the boundary of the stope and the knee of subsidence curve.At the same time,a 3DEC simulation model and an engineering example were carried out to examine the rules of theoretical model.The result suggests that the model and the rules accord to the test and have good building and protection engineering application values to the surface borehole.
文摘A nitrogen phosphorus synergistic flame retardant DCMA was synthesized frOm N-methylol acrylamide （NMA） and Diethyl Chlorophosphate （DC）. The reaction time and reaction mechanism were determined by tracking the reaction process using ultraviolet spectrum.The cotton cloth finished with DCMA, by rolling baking process, when the flame retardant concentration from 10% to 30%.the smoldering time decreased from 3S to 1 S, carbon length decreased from 10.5 to 6.3, limiting oxygen index by 31 increased to 36.4.the tensile breaking strength of cotton fabric decreased from 6.46MPa to 3.12MPa.
