Persulfate(PS)is a widely used oxidant for the chemical oxidation of organic pollutants.The accurate measurement of PS concentration is crucial for the practical application process.The iodometry is the most recommend...Persulfate(PS)is a widely used oxidant for the chemical oxidation of organic pollutants.The accurate measurement of PS concentration is crucial for the practical application process.The iodometry is the most recommended method for PS determination,and its principle is based on the redox reaction between S_(2)O_(8)^(2−)and iodide ions.However,hydrogen peroxide(H_(2)O_(2)),an important intermediate product in the process of PS use,often leads to abnormally high determination concentrations of PS.Given this,a novel method was developed for the determination of PS based on the principle of the oxidation of chloride ion(Cl^(−)).The concentration of PS is calculated according to the consumption of Cl^(−)concentration,which is not disturbed by H_(2)O_(2).The optimized test conditions were explored as:C(H^(+))=2 mol/L,T=80◦C,C(Cl^(−)):C(PS)=4:1 and t=30 min.Under the optimized conditions,the limit of detection and the limit of quantification of PS concentration determined by this method were 0.26 and 0.85 g/L,respectively.And the linear range of the PS determination was 1–100 g/L with an error of 0.53%-12.06%.The spike recovery rate for determining PS concentration in the actual wastewater ranged from 94.07%-109.52%.Interfering factors such as H_(2)O_(2),Fe^(3+),MnO_(2)and natural organic matter had almost no effect on the results.This method could not only accurately determine the concentration of PS in industrial wastewater,but also determine the purity of PS industrial products.展开更多
The development of highly active carbon material catalysts in catalytic wet air oxidation（CWAO）has attracted a great deal of attention. In this study different carbon material catalysts（multi-walled carbon nanotube...The development of highly active carbon material catalysts in catalytic wet air oxidation（CWAO）has attracted a great deal of attention. In this study different carbon material catalysts（multi-walled carbon nanotubes,carbon fibers and graphite） were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction,the removal of phenol was nearly100% over the functionalized multi-walled carbon,while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals,which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions,a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First,maleic acid is transformed directly into malonic acid. Second,acetic acid is oxidized into an unknown intermediate,which is then oxidized into CO2 and H2O. Finally,formic acid and oxalic acid can mutually interconvert when conditions are favorable.展开更多
The occurrence of antibiotics in the environment has recently raised serious concern regarding their potential threat to aquatic ecosystem and human health. In this study, the magnetic ion exchange（MIEX） resin was a...The occurrence of antibiotics in the environment has recently raised serious concern regarding their potential threat to aquatic ecosystem and human health. In this study, the magnetic ion exchange（MIEX） resin was applied for removing three commonly-used antibiotics, sulfamethoxazole（SMX）, tetracycline（TCN） and amoxicillin（AMX） from water.The results of batch experiments show that the maximum adsorption capacities on the MIEX resin for SMX, TCN and AMX were 789.32, 443.18 and 155.15 μg/m L at 25°C,respectively, which were 2–7 times that for the powdered activated carbon. The adsorption kinetics of antibiotics on the MIEX resin could be simulated by the pseudo-second-order model（R^2= 0.99）, and the adsorption isotherm data were well described by the Langmuir model（R^2= 0.97）. Solution p H exhibited a remarkable impact on the adsorption process and the absorbed concentrations of the tested antibiotics were obtained around the neutral p H.The MIEX resin could be easily regenerated by 2 mol/L Na Cl solution and maintained high adsorption removal for the tested antibiotics after regeneration. Anion exchange mechanism mainly controlled the adsorption of antibiotic and the formation of hydrogen binding between the antibiotic and resin can also result in the increase of adsorption capacity. The high adsorption capacity, fast adsorption rate and prominent reusability make the MIEX resin a potential adsorbent in the application for removing antibiotics from water.展开更多
Ni-P matrix composite coating reinforced by carbon nanotubes (CNTs) was deposit ed by electroless plating. The most important factors that influence the content of carbon nanotubes in deposits,such as agitation,surfac...Ni-P matrix composite coating reinforced by carbon nanotubes (CNTs) was deposit ed by electroless plating. The most important factors that influence the content of carbon nanotubes in deposits,such as agitation,surfactant and carbon nanot ubes concentration in the plating bath were investigated. The surface morphology,structure and properties of the Ni-P-CNTs coating were examined. It is found that the maximum content of carbon nanotubes in the deposits is independent of carbon nanotubes concentration in the plating bath when it is up to 5 mg/L. The test results show that the carbon nanotubes co-deposited do not change the str ucture of the Ni-P matrix of the composite coating,but greatly increase the ha rdness and wear resistance and decrease the friction coefficient of the Ni-P-C NTs composite coating with increasing content of carbon nanotubes in deposits.展开更多
This paper developed a fluorometric method for the sensitive determination of nonylphenol in water samples by preconcentration with zirconium doped titanium dioxide nanotubes solid phase extraction.The parameters on e...This paper developed a fluorometric method for the sensitive determination of nonylphenol in water samples by preconcentration with zirconium doped titanium dioxide nanotubes solid phase extraction.The parameters on extraction that would influence the enrichment performance such as the kind and volume of eluent,sample pH,sample flow rate,and sample volume were optimized in detail.Under the optimal conditions,the proposed method provided an excellent linear range of 1-150 mg/L and good LOD of 0.076 mg/L.The relative standard deviation（RSD,n = 6） was 2.8%.Proposed method was also used for the analysis of real water samples and the spiked recoveries were satisfied in the range of 98.7-103%.展开更多
The develop actuality and direction of FRP(fibre glass reinforced plastics) bolt in the world are analyzed The new type structure of FRP bolt was designed Trial data indicate that, all kinds of capability target o...The develop actuality and direction of FRP(fibre glass reinforced plastics) bolt in the world are analyzed The new type structure of FRP bolt was designed Trial data indicate that, all kinds of capability target of this FRP bolt all achieve and exceed the country standard, substitute present metal bolt,wood bolt and bamboo bolt and other side bolt, it can gain magnitude technology and economy benefit FRP bolt mechanization product line produce efficiency is high, its throughput a day are 750 base, this can meet demand of hit small mining company展开更多
To solve the disability of conventional model used in electrical leak location when measurement electrodes were buried under the liner, a new model of high voltage DC leak detection is developed. For single-liner land...To solve the disability of conventional model used in electrical leak location when measurement electrodes were buried under the liner, a new model of high voltage DC leak detection is developed. For single-liner landfill, the waste material layer, the geomembrane liner and the soil under the liner are simulated with infinite horizontal layers. The leak is regarded as two parts, one being negative current source at the entrance, and the other positive current source of the same size at the exit. Comparisons between the new theoretical model and conventional model show that conventional model is efficient in locating leaks in geomembane liner associating the dipole scanning above the liner but is ineffective when the measurement electrodes were buried under the liner. The new theoretical model data are in excellent agreement with experimental data not only above the liner but also under the liner.展开更多
According to the movement and change rules of mechanical structure of surrounding rock coal mass system during coal excavation, the mechanism of sudden instability and damage was found out. The criterions that disting...According to the movement and change rules of mechanical structure of surrounding rock coal mass system during coal excavation, the mechanism of sudden instability and damage was found out. The criterions that distinguishing the occurring of the pressure bump were put forward. This criteria have been applied successfully in the comprehensive prevent of pressure bumps in Tangshan colliery.展开更多
West China has rich mineral resources,especially in coal resources with very good mining conditions.Coal resource development is the one of important tasks in the Chinese“West Development”.Thus,the impact of coal re...West China has rich mineral resources,especially in coal resources with very good mining conditions.Coal resource development is the one of important tasks in the Chinese“West Development”.Thus,the impact of coal resources development on eco-environment and its restoration is worth studying.This study shows that there are many environmental problems such as land damage,coal wastes,damage of hydro-geological condition and pollution of water resource,airborne effluents(industrial exhausts and methane emission from underground),dust,waste,water.Land damage and land desertification are the most important environmental issue in west China.Therefore,the stress of environmental restoration should be desert presentation and disturbed-land reclamation.To control environmental damages and rehabilitate the eco-environment,environmental restoration techniques are also discussed.展开更多
By employing numerical modeling, similar material simulation and comprehen-sive field observation, investigations were made and patterns were obtained governing surrounding-rock stress distribution and strata behavior...By employing numerical modeling, similar material simulation and comprehen-sive field observation, investigations were made and patterns were obtained governing surrounding-rock stress distribution and strata behaviors. It shows that patterns governing displacement of FMC roadway surrounding rocks and those governing deformation of supports are basically the same along the strike, but the displacements vary greatly. The front stresses affect greater areas than the lateral stresses and their limit widths of equilib-rium zones and K are almost similar. The stress transmits very deep. Our findings offer scientific basis on which to determine parameters for coal pillar retaining and for roadway out-laying, thus increasing the recovery ratio and improving the maintenance of roadway.展开更多
A regrown composite fiber was synthesized during the sintering of diamond under high pressure 5.8 GPa and high temperature 1500℃for 1 min,using 3wt%MWCNTs as additive.SEM observation of the fiber after alkali and aci...A regrown composite fiber was synthesized during the sintering of diamond under high pressure 5.8 GPa and high temperature 1500℃for 1 min,using 3wt%MWCNTs as additive.SEM observation of the fiber after alkali and acid treatment revealed that the outer layer of the fiber is composed of nano-polycrystalline diamond.EDS,XPS,XRD and Raman spectrum analysis further identified that the fiber is composed of MWCNTs in the inner part and nano-polycrystalline diamond in the out layer.It is proposed that the untransformed MWCNTs may act as a template for the regrown outer layer of nano diamond fiber under high pressure and high temperature.展开更多
This article set forth two types of destructive form of stopping tunnel coal wall: destructive form in coal and destructive form in interface of coal layer. In addition, the mechanism of destruction in stopping tunnel...This article set forth two types of destructive form of stopping tunnel coal wall: destructive form in coal and destructive form in interface of coal layer. In addition, the mechanism of destruction in stopping tunnel coal wall is analyzed.展开更多
The whole process of dynamic surface subsidence deformation was divided into three stages as subsidence development,full subsidence and subsidence attenuation,and a new concept“deformation velocity in surface subside...The whole process of dynamic surface subsidence deformation was divided into three stages as subsidence development,full subsidence and subsidence attenuation,and a new concept“deformation velocity in surface subsidence”was also put forward.The emphasis was placed on the research on development and variation laws of deformation velocity in surface tilt and horizontal deformation velocity on strike main profile during the stage of dynamic full subsidence.What’s more,the dangerous periods of buildings liable to be damaged were given as well.展开更多
The designing method and the supporting mechanism of both bolt and small cable anchor for full seam roadway in the weaker thick coal seam are systematically analyzed, and the construction technology and the supporting...The designing method and the supporting mechanism of both bolt and small cable anchor for full seam roadway in the weaker thick coal seam are systematically analyzed, and the construction technology and the supporting results are briefly summarized.展开更多
The strata movement induced by sub-critical extraction is a problem not receiving due attention because of its relatively small magnitude of deformation.However,with the increase of mining depth,sub-critical extractio...The strata movement induced by sub-critical extraction is a problem not receiving due attention because of its relatively small magnitude of deformation.However,with the increase of mining depth,sub-critical extraction has become a general phenomenon.This calls for an in-depth investigation into the characteristics of ground movements observed under different extents of sub-critical extraction,so as to determine the appropriate mining technique for use.Following a discussion of the factors influencing the extent of super-critical extraction,the super-critical extraction extent evaluation criteria was presented,the characteristics and laws of the strata and ground movements caused by such an extraction condition were systematically analyzed,and the mechanism of surface subsidence induced by sub-critical extraction was revealed.The result of study may serve as a basis for the development of the strata and ground movement prediction model and the mining techniques appropriate for use at depth beneath surface structures and buildings.展开更多
Abstract In the study of sequence stratigraphy and litho-paleogeography, quantitative analysis, precise calculation and detailed comparison of tremendous geological data, such as field profiles, logging records and se...Abstract In the study of sequence stratigraphy and litho-paleogeography, quantitative analysis, precise calculation and detailed comparison of tremendous geological data, such as field profiles, logging records and seismic curves from different areas, are the basic requirements. In order to obtain a more reliable and precise result, this paper presents a novel method that combines spatial database analysis with the single-factor mapping technology to establish sequence stratigraphical succession and to map the Ordovician litho-paleogeography of the Ordos Basin, one of the largest oil-gas bearing basins in North China Platform. By using this method, all of the related basic geological data can be quantitatively analyzed and effectively managed. Various attributes of the basic stratigraphic units and their characters, such as sequence thickness, penecontemporaneous dolostone content, shallow water parget content, and terrigenous material content, can be fully utilized statistically in facies analysis and in mapping. Based on this analysis, this paper has be exerted single-factor isopachous mapping quantitatively for each of the Ordovician sequences in the basin, and finally synthesized multiple factors to reconstruct the litho-paleogeography for each of the sequence intervals. The study shows that the proposed method is quite effective and has a much higher resolution in recognizing litho-paleogeographic subunits compared with traditional ways. For example, in one of the Middle Ordovician sequence intervals （SQ19 in the Lower Majiagou Formation） of the Ordos Basin, the authors have successfully developed a mathematical formula to divide the distribution of various facies units substantially, such as old lands, submarine uplifts, supratidal zones, intertidal zones and subtidal zones.展开更多
The subsided area caused by mining is expanding gradually in coal mining areas.In order to occupy less or no farmland,many mining areas are constructing or intend to erect new buildings(structures)on the ground sites ...The subsided area caused by mining is expanding gradually in coal mining areas.In order to occupy less or no farmland,many mining areas are constructing or intend to erect new buildings(structures)on the ground sites above the worked-out areas.The long-term safety of the new buildings is of great importance.This matter should be,therefore,handled with great care.Following an analysis of the different conditions of the worked-out areas,and the characteristics of the failure of different types of worked-out areas and their overlying strata,the cause for the occurrence of residual deformation of the surface above the worked-out area was explained.The techniques for(evaluating)the stability of ground site for erecting new buildings above worked-out area,and the technical measures for protecting such buildings were proposed.The ground stability evaluation techniques were introduced by reference to specific cases.展开更多
The present study is focused on the roadway support in high stress composite soft rock. This paper expounds the two main features of roadway in soft rock, i.e., great deformation of surrounding rock and remarkable rhe...The present study is focused on the roadway support in high stress composite soft rock. This paper expounds the two main features of roadway in soft rock, i.e., great deformation of surrounding rock and remarkable rheological deformation. Furthermore, on the basis of analyzing physico chemical component of surrounding rock and the situation of the damaged roadway, the method of adopting strong bolting and shotcreting mesh for the primary support, bolting and grouting for the secondary support is put forward in light of the on the spot investigation of stress tension, mechanical parameter and engineering geology. The application reveals the method facilitates the continuation of west main roadway and the restoration of shaft station and chambers. Consequently, better techno economic results have been achieved.展开更多
The base vector between 2 poins and a high-precision geodetic height difference can be obtained by GPS.If the geodetic height of a point is known,the geodetic height of each observation point in a net can be obtained....The base vector between 2 poins and a high-precision geodetic height difference can be obtained by GPS.If the geodetic height of a point is known,the geodetic height of each observation point in a net can be obtained.When surveying the subsidence value in the mining-induced ground subsidence,the change of the height of monitoring point is needed.On the above theoretical basis,the problem involved in GPS observation of mining-induced ground subsidence and their counter measures were discussed,and an introduction was made that the subsidence value obtained in the monitoring mining-induced ground subsidence can use the change of height of geodetic as a alternative,the result of check on the accuracy and reliability of repetitions observations was analysed.Finally,the effect of errors on accuracy of GPS observation and their reduction measures were elaborated.展开更多
The quantitative analysis on soil erosion is very significant for macro-decision of soil loss,for quick control of natural disasters and for system of periodical report.Based on the research of 3S(GPS,GIS and RS),the ...The quantitative analysis on soil erosion is very significant for macro-decision of soil loss,for quick control of natural disasters and for system of periodical report.Based on the research of 3S(GPS,GIS and RS),the special information can be obtained by GPS or RS.Digital elevation model can be formed by GIS software,and at the same time,we can get some vector graph,such as landuse,vegetation type and soil type.Then the soil erosion of research area was calculated by USLE.The methods and techniques were discussed,including how to carve up polygons,how to capture the values of factors and how to differentiate the erosion intensity.展开更多
基金supported by the National Natural Science Foundation of China(No.21976192).
文摘Persulfate(PS)is a widely used oxidant for the chemical oxidation of organic pollutants.The accurate measurement of PS concentration is crucial for the practical application process.The iodometry is the most recommended method for PS determination,and its principle is based on the redox reaction between S_(2)O_(8)^(2−)and iodide ions.However,hydrogen peroxide(H_(2)O_(2)),an important intermediate product in the process of PS use,often leads to abnormally high determination concentrations of PS.Given this,a novel method was developed for the determination of PS based on the principle of the oxidation of chloride ion(Cl^(−)).The concentration of PS is calculated according to the consumption of Cl^(−)concentration,which is not disturbed by H_(2)O_(2).The optimized test conditions were explored as:C(H^(+))=2 mol/L,T=80◦C,C(Cl^(−)):C(PS)=4:1 and t=30 min.Under the optimized conditions,the limit of detection and the limit of quantification of PS concentration determined by this method were 0.26 and 0.85 g/L,respectively.And the linear range of the PS determination was 1–100 g/L with an error of 0.53%-12.06%.The spike recovery rate for determining PS concentration in the actual wastewater ranged from 94.07%-109.52%.Interfering factors such as H_(2)O_(2),Fe^(3+),MnO_(2)and natural organic matter had almost no effect on the results.This method could not only accurately determine the concentration of PS in industrial wastewater,but also determine the purity of PS industrial products.
基金supported by the National Natural Science Foundation of China (No.51078143)the Fundamental Research Funds for the Central Universities of China
文摘The development of highly active carbon material catalysts in catalytic wet air oxidation（CWAO）has attracted a great deal of attention. In this study different carbon material catalysts（multi-walled carbon nanotubes,carbon fibers and graphite） were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction,the removal of phenol was nearly100% over the functionalized multi-walled carbon,while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals,which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions,a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First,maleic acid is transformed directly into malonic acid. Second,acetic acid is oxidized into an unknown intermediate,which is then oxidized into CO2 and H2O. Finally,formic acid and oxalic acid can mutually interconvert when conditions are favorable.
基金supported by the National Natural Science Foundation of China(No.21107127)the Ministry of Science and Technology of China(No.2012AA062606)
文摘The occurrence of antibiotics in the environment has recently raised serious concern regarding their potential threat to aquatic ecosystem and human health. In this study, the magnetic ion exchange（MIEX） resin was applied for removing three commonly-used antibiotics, sulfamethoxazole（SMX）, tetracycline（TCN） and amoxicillin（AMX） from water.The results of batch experiments show that the maximum adsorption capacities on the MIEX resin for SMX, TCN and AMX were 789.32, 443.18 and 155.15 μg/m L at 25°C,respectively, which were 2–7 times that for the powdered activated carbon. The adsorption kinetics of antibiotics on the MIEX resin could be simulated by the pseudo-second-order model（R^2= 0.99）, and the adsorption isotherm data were well described by the Langmuir model（R^2= 0.97）. Solution p H exhibited a remarkable impact on the adsorption process and the absorbed concentrations of the tested antibiotics were obtained around the neutral p H.The MIEX resin could be easily regenerated by 2 mol/L Na Cl solution and maintained high adsorption removal for the tested antibiotics after regeneration. Anion exchange mechanism mainly controlled the adsorption of antibiotic and the formation of hydrogen binding between the antibiotic and resin can also result in the increase of adsorption capacity. The high adsorption capacity, fast adsorption rate and prominent reusability make the MIEX resin a potential adsorbent in the application for removing antibiotics from water.
文摘Ni-P matrix composite coating reinforced by carbon nanotubes (CNTs) was deposit ed by electroless plating. The most important factors that influence the content of carbon nanotubes in deposits,such as agitation,surfactant and carbon nanot ubes concentration in the plating bath were investigated. The surface morphology,structure and properties of the Ni-P-CNTs coating were examined. It is found that the maximum content of carbon nanotubes in the deposits is independent of carbon nanotubes concentration in the plating bath when it is up to 5 mg/L. The test results show that the carbon nanotubes co-deposited do not change the str ucture of the Ni-P matrix of the composite coating,but greatly increase the ha rdness and wear resistance and decrease the friction coefficient of the Ni-P-C NTs composite coating with increasing content of carbon nanotubes in deposits.
文摘This paper developed a fluorometric method for the sensitive determination of nonylphenol in water samples by preconcentration with zirconium doped titanium dioxide nanotubes solid phase extraction.The parameters on extraction that would influence the enrichment performance such as the kind and volume of eluent,sample pH,sample flow rate,and sample volume were optimized in detail.Under the optimal conditions,the proposed method provided an excellent linear range of 1-150 mg/L and good LOD of 0.076 mg/L.The relative standard deviation（RSD,n = 6） was 2.8%.Proposed method was also used for the analysis of real water samples and the spiked recoveries were satisfied in the range of 98.7-103%.
文摘The develop actuality and direction of FRP(fibre glass reinforced plastics) bolt in the world are analyzed The new type structure of FRP bolt was designed Trial data indicate that, all kinds of capability target of this FRP bolt all achieve and exceed the country standard, substitute present metal bolt,wood bolt and bamboo bolt and other side bolt, it can gain magnitude technology and economy benefit FRP bolt mechanization product line produce efficiency is high, its throughput a day are 750 base, this can meet demand of hit small mining company
基金Project supported by the National High-Technology Research and Development Program of China (Grant No. 863-2001AA644010)
文摘To solve the disability of conventional model used in electrical leak location when measurement electrodes were buried under the liner, a new model of high voltage DC leak detection is developed. For single-liner landfill, the waste material layer, the geomembrane liner and the soil under the liner are simulated with infinite horizontal layers. The leak is regarded as two parts, one being negative current source at the entrance, and the other positive current source of the same size at the exit. Comparisons between the new theoretical model and conventional model show that conventional model is efficient in locating leaks in geomembane liner associating the dipole scanning above the liner but is ineffective when the measurement electrodes were buried under the liner. The new theoretical model data are in excellent agreement with experimental data not only above the liner but also under the liner.
文摘According to the movement and change rules of mechanical structure of surrounding rock coal mass system during coal excavation, the mechanism of sudden instability and damage was found out. The criterions that distinguishing the occurring of the pressure bump were put forward. This criteria have been applied successfully in the comprehensive prevent of pressure bumps in Tangshan colliery.
基金Project(40071045)supported by the National Natural Science Foundationproject(20020290014)supported by Specialized Research Fund for the Doctoral Program of Higher Educationproject(2003AA322040)supported by High-Tech Program
文摘West China has rich mineral resources,especially in coal resources with very good mining conditions.Coal resource development is the one of important tasks in the Chinese“West Development”.Thus,the impact of coal resources development on eco-environment and its restoration is worth studying.This study shows that there are many environmental problems such as land damage,coal wastes,damage of hydro-geological condition and pollution of water resource,airborne effluents(industrial exhausts and methane emission from underground),dust,waste,water.Land damage and land desertification are the most important environmental issue in west China.Therefore,the stress of environmental restoration should be desert presentation and disturbed-land reclamation.To control environmental damages and rehabilitate the eco-environment,environmental restoration techniques are also discussed.
基金Supported by the Natural Sciences of Anhui Provincial Education Division(2002kj286ZD,01044403)
文摘By employing numerical modeling, similar material simulation and comprehen-sive field observation, investigations were made and patterns were obtained governing surrounding-rock stress distribution and strata behaviors. It shows that patterns governing displacement of FMC roadway surrounding rocks and those governing deformation of supports are basically the same along the strike, but the displacements vary greatly. The front stresses affect greater areas than the lateral stresses and their limit widths of equilib-rium zones and K are almost similar. The stress transmits very deep. Our findings offer scientific basis on which to determine parameters for coal pillar retaining and for roadway out-laying, thus increasing the recovery ratio and improving the maintenance of roadway.
基金Supported by the National Natural Science Foundation of China(No.50342017)by the Natural Science Foundation of Beijing(No.2042019)
文摘A regrown composite fiber was synthesized during the sintering of diamond under high pressure 5.8 GPa and high temperature 1500℃for 1 min,using 3wt%MWCNTs as additive.SEM observation of the fiber after alkali and acid treatment revealed that the outer layer of the fiber is composed of nano-polycrystalline diamond.EDS,XPS,XRD and Raman spectrum analysis further identified that the fiber is composed of MWCNTs in the inner part and nano-polycrystalline diamond in the out layer.It is proposed that the untransformed MWCNTs may act as a template for the regrown outer layer of nano diamond fiber under high pressure and high temperature.
文摘This article set forth two types of destructive form of stopping tunnel coal wall: destructive form in coal and destructive form in interface of coal layer. In addition, the mechanism of destruction in stopping tunnel coal wall is analyzed.
文摘The whole process of dynamic surface subsidence deformation was divided into three stages as subsidence development,full subsidence and subsidence attenuation,and a new concept“deformation velocity in surface subsidence”was also put forward.The emphasis was placed on the research on development and variation laws of deformation velocity in surface tilt and horizontal deformation velocity on strike main profile during the stage of dynamic full subsidence.What’s more,the dangerous periods of buildings liable to be damaged were given as well.
文摘The designing method and the supporting mechanism of both bolt and small cable anchor for full seam roadway in the weaker thick coal seam are systematically analyzed, and the construction technology and the supporting results are briefly summarized.
基金Project supported by Doctoral Study Courses Foundation and Post-Doctoral Scientific Foundation.
文摘The strata movement induced by sub-critical extraction is a problem not receiving due attention because of its relatively small magnitude of deformation.However,with the increase of mining depth,sub-critical extraction has become a general phenomenon.This calls for an in-depth investigation into the characteristics of ground movements observed under different extents of sub-critical extraction,so as to determine the appropriate mining technique for use.Following a discussion of the factors influencing the extent of super-critical extraction,the super-critical extraction extent evaluation criteria was presented,the characteristics and laws of the strata and ground movements caused by such an extraction condition were systematically analyzed,and the mechanism of surface subsidence induced by sub-critical extraction was revealed.The result of study may serve as a basis for the development of the strata and ground movement prediction model and the mining techniques appropriate for use at depth beneath surface structures and buildings.
基金Supported by the National Natural Science Foundation of China for the Innovation Group Project(No. 40621002)
文摘Abstract In the study of sequence stratigraphy and litho-paleogeography, quantitative analysis, precise calculation and detailed comparison of tremendous geological data, such as field profiles, logging records and seismic curves from different areas, are the basic requirements. In order to obtain a more reliable and precise result, this paper presents a novel method that combines spatial database analysis with the single-factor mapping technology to establish sequence stratigraphical succession and to map the Ordovician litho-paleogeography of the Ordos Basin, one of the largest oil-gas bearing basins in North China Platform. By using this method, all of the related basic geological data can be quantitatively analyzed and effectively managed. Various attributes of the basic stratigraphic units and their characters, such as sequence thickness, penecontemporaneous dolostone content, shallow water parget content, and terrigenous material content, can be fully utilized statistically in facies analysis and in mapping. Based on this analysis, this paper has be exerted single-factor isopachous mapping quantitatively for each of the Ordovician sequences in the basin, and finally synthesized multiple factors to reconstruct the litho-paleogeography for each of the sequence intervals. The study shows that the proposed method is quite effective and has a much higher resolution in recognizing litho-paleogeographic subunits compared with traditional ways. For example, in one of the Middle Ordovician sequence intervals （SQ19 in the Lower Majiagou Formation） of the Ordos Basin, the authors have successfully developed a mathematical formula to divide the distribution of various facies units substantially, such as old lands, submarine uplifts, supratidal zones, intertidal zones and subtidal zones.
文摘The subsided area caused by mining is expanding gradually in coal mining areas.In order to occupy less or no farmland,many mining areas are constructing or intend to erect new buildings(structures)on the ground sites above the worked-out areas.The long-term safety of the new buildings is of great importance.This matter should be,therefore,handled with great care.Following an analysis of the different conditions of the worked-out areas,and the characteristics of the failure of different types of worked-out areas and their overlying strata,the cause for the occurrence of residual deformation of the surface above the worked-out area was explained.The techniques for(evaluating)the stability of ground site for erecting new buildings above worked-out area,and the technical measures for protecting such buildings were proposed.The ground stability evaluation techniques were introduced by reference to specific cases.
文摘The present study is focused on the roadway support in high stress composite soft rock. This paper expounds the two main features of roadway in soft rock, i.e., great deformation of surrounding rock and remarkable rheological deformation. Furthermore, on the basis of analyzing physico chemical component of surrounding rock and the situation of the damaged roadway, the method of adopting strong bolting and shotcreting mesh for the primary support, bolting and grouting for the secondary support is put forward in light of the on the spot investigation of stress tension, mechanical parameter and engineering geology. The application reveals the method facilitates the continuation of west main roadway and the restoration of shaft station and chambers. Consequently, better techno economic results have been achieved.
基金FoundatianitemProject(99 mining 20267)supported by Coal Science Fund.
文摘The base vector between 2 poins and a high-precision geodetic height difference can be obtained by GPS.If the geodetic height of a point is known,the geodetic height of each observation point in a net can be obtained.When surveying the subsidence value in the mining-induced ground subsidence,the change of the height of monitoring point is needed.On the above theoretical basis,the problem involved in GPS observation of mining-induced ground subsidence and their counter measures were discussed,and an introduction was made that the subsidence value obtained in the monitoring mining-induced ground subsidence can use the change of height of geodetic as a alternative,the result of check on the accuracy and reliability of repetitions observations was analysed.Finally,the effect of errors on accuracy of GPS observation and their reduction measures were elaborated.
基金Project(2001AA24503)supported by the High-Tech Research Programof ChinaProject(2002CB111503)supported by the Natronal KeyFundamental Research and Development Programof China.
文摘The quantitative analysis on soil erosion is very significant for macro-decision of soil loss,for quick control of natural disasters and for system of periodical report.Based on the research of 3S(GPS,GIS and RS),the special information can be obtained by GPS or RS.Digital elevation model can be formed by GIS software,and at the same time,we can get some vector graph,such as landuse,vegetation type and soil type.Then the soil erosion of research area was calculated by USLE.The methods and techniques were discussed,including how to carve up polygons,how to capture the values of factors and how to differentiate the erosion intensity.
