Cs_(x)WO_(3)/TiO_(2) composites with full-spectrum catalytic activity were prepared by solvothermal reaction.The composites were characterized using X-ray diffraction(XRD)analysis,scanning electron microscopy(SEM),tra...Cs_(x)WO_(3)/TiO_(2) composites with full-spectrum catalytic activity were prepared by solvothermal reaction.The composites were characterized using X-ray diffraction(XRD)analysis,scanning electron microscopy(SEM),transmission electron microscopy(TEM),specific surface area testing,X-ray photoelectron spectroscopy(XPS),and UV-Vis diffuse reflectance spectra(UV-Vis DRS).Cs_(x)WO_(3) and TiO_(2) were uniformly bonded together in the compos-ites.The heterojunction structure was formed.The band gap was reduced from 2.75 to 2.65 eV.The photocatalytic property of Cs_(x)WO_(3)/TiO_(2)was demonstrated by the degradation rates of 20 mg·L^(-1) methylene blue dye,which were 99.7%,91.4%,and 70.7%under irradiation from a 300 W high-pressure mercury lamp,a 500 W xenon lamp,and a 400 W infrared lamp,respectively.After five cycles of photocatalytic degradation,the composite photocatalyst still showed a degradation efficiency of 87.6%.This indicates that Cs_(x)WO_(3)/TiO_(2) has good photocatalytic degradability and cyclic stability.The photocatalytic mechanism of Cs_(x)WO_(3)/TiO_(2)was investigated.The trapping experiments of the active species showed that the main active substances were the empty hole(h+)and hydroxyl radical(·OH).展开更多
The preparation technique and properties of Ag-type inorganic antibiotic material carried by Al2O3 were studied. The results show that the material has good antibiotic and safety properties, the acute toxicity taken b...The preparation technique and properties of Ag-type inorganic antibiotic material carried by Al2O3 were studied. The results show that the material has good antibiotic and safety properties, the acute toxicity taken by stomata is LD 50 >8000mg/kg （little and big white rats）, and the normal quantity in subacute toxicity test is 80mg/（kg·d）. The better mass fraction of doping Ag2O in antibiotic material carried by Al2O3 is 4%CD*28%, and the optimal sintering temperature is from 1000℃ to 1100℃.展开更多
Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equi...Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equilibrium method. The calculation results present that the safety factors of pillars in Sections 19, 20, 24, 28 are less than 1.3, and those of unstable sections are identified preliminarily. Further, a numerical investigation in Sections 18, 20, 22, 24, 25 and 28 implemented with numerical code RFPA20 is employed to further validate the pillar performance and the stability of stopes. The numerical results show the pillars in Sections 18, 22 and 24 are stable and the designed pillar size is suitable. The width of the ore body near Section 28 averages 20 m, failure occurs in the left stope, but the boundary pillars near Section 28 maintain good performance. The pillars in Sections 20 and 25 are unstable which are mainly affected by the Faults F8 and F18. The existence of faults alters the stress distribution, failure mode and water inrush pathway. This work provides a meaningful standard for boundary pillar and stope design in a mine as it transitions from an open pit to underground.展开更多
With the help of similar material simulation test,time series system for induced caving of roof in continuous mining under complex backfill in ore body No.92 of Tongkeng Tin Mine was studied. According to the similari...With the help of similar material simulation test,time series system for induced caving of roof in continuous mining under complex backfill in ore body No.92 of Tongkeng Tin Mine was studied. According to the similarity theory,a two-dimensional similar simulation test-bed was constructed. The stress and displacement that change along with the advance of mining were acquired and analyzed automatically by data system. The processes of continuous mining of ore-block in 5 intervals and artificial induced caving of roof were simulated. The results of the test show that ore body remained as safety roof in thickness of 15 m guarantees the safe advance of stoping work face. Caving of safety roof puts in practice at the first two mining intervals when the third interval of continuous mining is finished,and one interval as the safety distance should be kept all the time between stopping and caving. While mining in the last interval,pre-slotting should be implemented first of all,and the roof of the last two mining intervals is caved simultaneously. Only this kind of time series system can be an efficient and safe way for induced caving of roof in continuous mining.展开更多
文摘Cs_(x)WO_(3)/TiO_(2) composites with full-spectrum catalytic activity were prepared by solvothermal reaction.The composites were characterized using X-ray diffraction(XRD)analysis,scanning electron microscopy(SEM),transmission electron microscopy(TEM),specific surface area testing,X-ray photoelectron spectroscopy(XPS),and UV-Vis diffuse reflectance spectra(UV-Vis DRS).Cs_(x)WO_(3) and TiO_(2) were uniformly bonded together in the compos-ites.The heterojunction structure was formed.The band gap was reduced from 2.75 to 2.65 eV.The photocatalytic property of Cs_(x)WO_(3)/TiO_(2)was demonstrated by the degradation rates of 20 mg·L^(-1) methylene blue dye,which were 99.7%,91.4%,and 70.7%under irradiation from a 300 W high-pressure mercury lamp,a 500 W xenon lamp,and a 400 W infrared lamp,respectively.After five cycles of photocatalytic degradation,the composite photocatalyst still showed a degradation efficiency of 87.6%.This indicates that Cs_(x)WO_(3)/TiO_(2) has good photocatalytic degradability and cyclic stability.The photocatalytic mechanism of Cs_(x)WO_(3)/TiO_(2)was investigated.The trapping experiments of the active species showed that the main active substances were the empty hole(h+)and hydroxyl radical(·OH).
文摘The preparation technique and properties of Ag-type inorganic antibiotic material carried by Al2O3 were studied. The results show that the material has good antibiotic and safety properties, the acute toxicity taken by stomata is LD 50 >8000mg/kg （little and big white rats）, and the normal quantity in subacute toxicity test is 80mg/（kg·d）. The better mass fraction of doping Ag2O in antibiotic material carried by Al2O3 is 4%CD*28%, and the optimal sintering temperature is from 1000℃ to 1100℃.
基金Projects(1004025,51174044,50934006)supported by the National Natural Science FoundationProject(2011AA060400)supported by the National High Technique Research and Development Program of ChinaProject(Sklgduek1113)supported by Funds of the State Key Laboratory for Geomechanics&Deep Underground Engineering,Chinese University of Mining and Technology,China
文摘Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equilibrium method. The calculation results present that the safety factors of pillars in Sections 19, 20, 24, 28 are less than 1.3, and those of unstable sections are identified preliminarily. Further, a numerical investigation in Sections 18, 20, 22, 24, 25 and 28 implemented with numerical code RFPA20 is employed to further validate the pillar performance and the stability of stopes. The numerical results show the pillars in Sections 18, 22 and 24 are stable and the designed pillar size is suitable. The width of the ore body near Section 28 averages 20 m, failure occurs in the left stope, but the boundary pillars near Section 28 maintain good performance. The pillars in Sections 20 and 25 are unstable which are mainly affected by the Faults F8 and F18. The existence of faults alters the stress distribution, failure mode and water inrush pathway. This work provides a meaningful standard for boundary pillar and stope design in a mine as it transitions from an open pit to underground.
基金Project(50490274) supported by the National Natural Science Foundation of ChinaProject(20050533035) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(1343-77236) supported by the Doctor Degree Paper Innovation Engineering of Central South University, China
文摘With the help of similar material simulation test,time series system for induced caving of roof in continuous mining under complex backfill in ore body No.92 of Tongkeng Tin Mine was studied. According to the similarity theory,a two-dimensional similar simulation test-bed was constructed. The stress and displacement that change along with the advance of mining were acquired and analyzed automatically by data system. The processes of continuous mining of ore-block in 5 intervals and artificial induced caving of roof were simulated. The results of the test show that ore body remained as safety roof in thickness of 15 m guarantees the safe advance of stoping work face. Caving of safety roof puts in practice at the first two mining intervals when the third interval of continuous mining is finished,and one interval as the safety distance should be kept all the time between stopping and caving. While mining in the last interval,pre-slotting should be implemented first of all,and the roof of the last two mining intervals is caved simultaneously. Only this kind of time series system can be an efficient and safe way for induced caving of roof in continuous mining.
