Fetr6 is an underground mine in which chromite is extracted using stope and pillar mining method. Despite of all improving works such as roof supporting and replacing of ore pillars with concrete pillars, pillar No. 1...Fetr6 is an underground mine in which chromite is extracted using stope and pillar mining method. Despite of all improving works such as roof supporting and replacing of ore pillars with concrete pillars, pillar No. 19 failed and other pillars failed progressively as a domino effect and 4000 m2 of mine collapsed within a few minutes, consequently. For detail investigation, two 3-D numerical models were developed by 3Dec. The first, a base model, was used for estimation of stress on pillars just before failure and the other for investigation of rock burst in pillar No. 19. The results show that discontinuity parameters such as friction angle and shear stiffness is critical parameters in this pillar failure. In addition, it indicates that W/H ratio equal 0.3, the lack of ore extraction strategy and inadequate roof support are the major reasons for this failure. In this paper, the procedure of study was described.展开更多
A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analy...A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P1^- with a = 9.7029（4）, b = 11.9601（5）, c = 12.1788（4） A, α = 71.6990（10）, β = 71.8740（10）, γ = 74.4680（10）°, V = 1252.39（8） A^3, C52H48Cd2N4O16, Mr = 1209.76, Z= 1, Dc = 1.604 g/cm^3,μ = 0.925 mm^-1, F（000） = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections （I 〉 2σ（I））. Two intramolecular Cd（II） centers of this complex are encircled by two dpa^2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional （3D） supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.展开更多
A n-Hexyl NH 3Sr 2Nb 3O 10 is obtained by the stepwise ion-exchange reaction,then is dispersed in aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate,[Fe 3(OCOCH 3) 7OH·2H 2O]NO 3,and the ...A n-Hexyl NH 3Sr 2Nb 3O 10 is obtained by the stepwise ion-exchange reaction,then is dispersed in aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate,[Fe 3(OCOCH 3) 7OH·2H 2O]NO 3,and the interlayer potassium cations of the perovskite niobate are exchanged with the partially hydrolyzed trinuclear acetato complex ions.On heating,the exchanged complex ions are converted into iron oxide pillars which keep the perovskite sheets apart.The product is characterized by XRD,SEM,EDAX and surface area measurement respectively.展开更多
Magnetically modified Fe-Al pillared bentonite（Fe3O4/ Fe-Al-Bent） was prepared via chemical co-precipitation method and characterized by powder X-ray diffraction（XRD）, Brunauer-EmmettTeller（BET）, Fourier transfo...Magnetically modified Fe-Al pillared bentonite（Fe3O4/ Fe-Al-Bent） was prepared via chemical co-precipitation method and characterized by powder X-ray diffraction（XRD）, Brunauer-EmmettTeller（BET）, Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM）. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous catalysts in the presence of H2O2. The experimental result indicated that the synthetic materials had a high catalytic activity and good reusability.展开更多
文摘Fetr6 is an underground mine in which chromite is extracted using stope and pillar mining method. Despite of all improving works such as roof supporting and replacing of ore pillars with concrete pillars, pillar No. 19 failed and other pillars failed progressively as a domino effect and 4000 m2 of mine collapsed within a few minutes, consequently. For detail investigation, two 3-D numerical models were developed by 3Dec. The first, a base model, was used for estimation of stress on pillars just before failure and the other for investigation of rock burst in pillar No. 19. The results show that discontinuity parameters such as friction angle and shear stiffness is critical parameters in this pillar failure. In addition, it indicates that W/H ratio equal 0.3, the lack of ore extraction strategy and inadequate roof support are the major reasons for this failure. In this paper, the procedure of study was described.
基金the State Key Basic Research and Development Plan of China (001CB108906)the Knowledge Innovation Program of the Chinese Academy of Sciences, the NSF (2006J0015)the Major Special Foundation of Fujian Province (2005HZ1027, 2005HZ01-1)
文摘A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P1^- with a = 9.7029（4）, b = 11.9601（5）, c = 12.1788（4） A, α = 71.6990（10）, β = 71.8740（10）, γ = 74.4680（10）°, V = 1252.39（8） A^3, C52H48Cd2N4O16, Mr = 1209.76, Z= 1, Dc = 1.604 g/cm^3,μ = 0.925 mm^-1, F（000） = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections （I 〉 2σ（I））. Two intramolecular Cd（II） centers of this complex are encircled by two dpa^2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional （3D） supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.
基金FundedbytheNationalNaturalScienceFoundationofChi na (No .5 0 0 0 2 0 0 7) MajorProgramofMinistryofEducation (No.0 2 0 1)andOpenFoundationofStateKeyLabofAdvancedTech .forMaterialsSynthesisandProcessing.
文摘A n-Hexyl NH 3Sr 2Nb 3O 10 is obtained by the stepwise ion-exchange reaction,then is dispersed in aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate,[Fe 3(OCOCH 3) 7OH·2H 2O]NO 3,and the interlayer potassium cations of the perovskite niobate are exchanged with the partially hydrolyzed trinuclear acetato complex ions.On heating,the exchanged complex ions are converted into iron oxide pillars which keep the perovskite sheets apart.The product is characterized by XRD,SEM,EDAX and surface area measurement respectively.
基金Funded by the Specialized Research Fund for the Doctoral Program of Higher Education of China(20114219110002)the Natural Science Foundation of Hubei Province(Nos.2014CFB810&2014CFB812)
文摘Magnetically modified Fe-Al pillared bentonite（Fe3O4/ Fe-Al-Bent） was prepared via chemical co-precipitation method and characterized by powder X-ray diffraction（XRD）, Brunauer-EmmettTeller（BET）, Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM）. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous catalysts in the presence of H2O2. The experimental result indicated that the synthetic materials had a high catalytic activity and good reusability.
