This study mainly investigates the mechanical mechanism of overlying strata breaking and the development of fractured zones during close-distance coal seam group mining in the Gaojialiang coal mine.First,a mechanical ...This study mainly investigates the mechanical mechanism of overlying strata breaking and the development of fractured zones during close-distance coal seam group mining in the Gaojialiang coal mine.First,a mechanical model for the second"activation"of broken overlying strata is established,and the related mechanical"activation"conditions are obtained.A recursive formula for calculating the separation distance of overlying strata is deduced.Second,a height determining method for predicting the height of fractured zones during close-distance coal seam group mining is proposed based on two values,namely,the separation distance and ultimate subsidence value of overlying strata.This method is applied to calculate the fractured zone heights in nos.20107 and 20307 mining faces.The calculated results are almost equal to the field observation results.Third,a modified formula for calculating the height of a waterflowing fractured zone is proposed.A comparison of the calculated and observed results shows that the errors are small.The height determining method and modified formula not only build a theoretical foundation for water conservation mining at the Gaojialiang coal mine,but also provide a reference for estimating the height of water-flowing fractured zones in other coal mines with similar conditions.展开更多
分析比较了我国《室外排水设计规范》、德国排水技术协会(ATV)和国际水协会(IWA)关于城镇污水污泥产率的计算公式,总结了剩余污泥的主要来源,并结合德国ATV中对于除磷产泥量的计算以及我国进水水质中fv值较低的现状,提出基于IWA污泥产...分析比较了我国《室外排水设计规范》、德国排水技术协会(ATV)和国际水协会(IWA)关于城镇污水污泥产率的计算公式,总结了剩余污泥的主要来源,并结合德国ATV中对于除磷产泥量的计算以及我国进水水质中fv值较低的现状,提出基于IWA污泥产率的修正公式。通过对无锡市某污水处理厂2014年污泥产率的核算,可知修正公式核算值2.32 t DS/10~4m^3与实际值2.33 t DS/10~4m^3基本一致,其中核算值中进水惰性SS沉积量占总产泥量的80.6%,且fv对污泥产率的影响较大,因此建议在《室外排水设计规范》再次修订时考虑fv对污泥产率的影响。展开更多
We modified Mulikens overlap population n(A, B)=2∑Bλ∑Aμ∑in_ic~*_A,μic_B,λis_Aμ,Bλ and obtained an experiential formula N(A,B)=N_A(A,B)+N_B(A,B) of judging bond strength, where N_A(A, B)=\{Z_AN^2_A(2∑Bλ∑...We modified Mulikens overlap population n(A, B)=2∑Bλ∑Aμ∑in_ic~*_A,μic_B,λis_Aμ,Bλ and obtained an experiential formula N(A,B)=N_A(A,B)+N_B(A,B) of judging bond strength, where N_A(A, B)=\{Z_AN^2_A(2∑Bλ∑Aμ∑i\}n_ic~*_A,μic_B,λis_Aμ,Bλ), N_B(A, B)=Z_BN^2_B(2∑Bλ∑Aμ∑in_ic~*_A,μic_B,λis_Aμ,Bλ). Twenty-eight bonds calculated by IEHM method and 11 monohydrides calculated by using 6-31G~** basis sets at Hartree-Fock level, electronic correlation effects are also considered through MP2/6-31G~**, were used to verify our experiential formula. Compared with the judgment of chemical bond strength by means of Mulikens overlap population, our experiential formula has a more obvious improvement as a judgment of bond strength than Mulikens overlap population. As a judgment of chemical bond strength between atoms in molecules, the experiential formula has conquered some limitations of Mulikens overlap population, and accorded with the experimental results.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51474137,and 51574154)Shandong Province Natural Science Fund(No.ZR201709180101)+1 种基金Tai’shan Scholar Engineering Construction Fund of Shandong Province of ChinaPostgraduate Technology Innovation Project of Shandong University of Science and Technology(No.SDKDYC 180103).
文摘This study mainly investigates the mechanical mechanism of overlying strata breaking and the development of fractured zones during close-distance coal seam group mining in the Gaojialiang coal mine.First,a mechanical model for the second"activation"of broken overlying strata is established,and the related mechanical"activation"conditions are obtained.A recursive formula for calculating the separation distance of overlying strata is deduced.Second,a height determining method for predicting the height of fractured zones during close-distance coal seam group mining is proposed based on two values,namely,the separation distance and ultimate subsidence value of overlying strata.This method is applied to calculate the fractured zone heights in nos.20107 and 20307 mining faces.The calculated results are almost equal to the field observation results.Third,a modified formula for calculating the height of a waterflowing fractured zone is proposed.A comparison of the calculated and observed results shows that the errors are small.The height determining method and modified formula not only build a theoretical foundation for water conservation mining at the Gaojialiang coal mine,but also provide a reference for estimating the height of water-flowing fractured zones in other coal mines with similar conditions.
文摘分析比较了我国《室外排水设计规范》、德国排水技术协会(ATV)和国际水协会(IWA)关于城镇污水污泥产率的计算公式,总结了剩余污泥的主要来源,并结合德国ATV中对于除磷产泥量的计算以及我国进水水质中fv值较低的现状,提出基于IWA污泥产率的修正公式。通过对无锡市某污水处理厂2014年污泥产率的核算,可知修正公式核算值2.32 t DS/10~4m^3与实际值2.33 t DS/10~4m^3基本一致,其中核算值中进水惰性SS沉积量占总产泥量的80.6%,且fv对污泥产率的影响较大,因此建议在《室外排水设计规范》再次修订时考虑fv对污泥产率的影响。
文摘We modified Mulikens overlap population n(A, B)=2∑Bλ∑Aμ∑in_ic~*_A,μic_B,λis_Aμ,Bλ and obtained an experiential formula N(A,B)=N_A(A,B)+N_B(A,B) of judging bond strength, where N_A(A, B)=\{Z_AN^2_A(2∑Bλ∑Aμ∑i\}n_ic~*_A,μic_B,λis_Aμ,Bλ), N_B(A, B)=Z_BN^2_B(2∑Bλ∑Aμ∑in_ic~*_A,μic_B,λis_Aμ,Bλ). Twenty-eight bonds calculated by IEHM method and 11 monohydrides calculated by using 6-31G~** basis sets at Hartree-Fock level, electronic correlation effects are also considered through MP2/6-31G~**, were used to verify our experiential formula. Compared with the judgment of chemical bond strength by means of Mulikens overlap population, our experiential formula has a more obvious improvement as a judgment of bond strength than Mulikens overlap population. As a judgment of chemical bond strength between atoms in molecules, the experiential formula has conquered some limitations of Mulikens overlap population, and accorded with the experimental results.
