Elective culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in 9K medium modified with pyrrhotite was studied.Bioleaching of flotation concentrate of sphalerite by the selected bacteria was ca...Elective culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in 9K medium modified with pyrrhotite was studied.Bioleaching of flotation concentrate of sphalerite by the selected bacteria was carried out.The results show that the microorganisms cultured by pyrrhotite are a mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans,of which the capability to oxidize ferrous to ferric irons is enhanced by the high mass ratio of Fe to S in pyrrhotite.Three pyrrhotite samples were separated into various parts with corresponding S/Fe ratios by magnetic separation and were used to culture the elective bacteria as the substrate.The association of the cultures could provide a more rapid and complete oxidation of sphalerite than that of bacteria cultivated by conventional methods.展开更多
Two-dimensional tidal open boundary conditions of the M2 constituent in the Bohai and Yellow Seas(BYS) have been estimated by assimilating T/P altimeter data.During inversion,independent point(IP) strategy was used,in...Two-dimensional tidal open boundary conditions of the M2 constituent in the Bohai and Yellow Seas(BYS) have been estimated by assimilating T/P altimeter data.During inversion,independent point(IP) strategy was used,in which several IPs on the open boundary is assumed,values at these IPs can be optimized with an adjoint method,and those at other grid points are determined by linearly interpolating the values at IPs.The reasonability and feasibility of the model are tested by ideal twin experiments.In the practical experiment(PE) after assimilation,the cost function may reach 1% or less of its initial value.Mean absolute errors in amplitude and phase can be less than 5 cm and 5°,respectively,and the obtained co-chart can show the character of the M2 constituent in the BYS.The results of the PE indicate that using only two IPs on the open boundary can yield better simulated results.展开更多
This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village ho...This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village houses. The stratum structure control action of mining subsidence was used to design the mining and pillar width. To further raise resources recovery, we adopted the mutative scheme of mining and pillar width. Observation was carried out while mining. Research shows there is feasibility of the strip mining technology to protecting the village buildings of the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. Finally, subsidence parameters of strip mining were obtained. It is the basic data of the strip mining of the coal field at the north of the Yellow River.展开更多
The unsaturated undisturbed quaternary system middle pleistocene loess,a typical unsaturated soil,often occurs in the implementation of western development strategy.To obtain the shearing strength characteristics of t...The unsaturated undisturbed quaternary system middle pleistocene loess,a typical unsaturated soil,often occurs in the implementation of western development strategy.To obtain the shearing strength characteristics of this unsaturated undisturbed loess,based on the analysis of mineral composition,the triaxial shear test of undisturbed quaternary system middle pleistocene loess under different moisture contents is conducted with the specialized triaxial instrument for unsaturated soil.The test results show that the mainly mineral composition of undisturbed quaternary system middle pleistocene loess is quartz and albite.Under the same confining pressure,the matric suction increases with the decrease of moisture content.The smaller the moisture content,the larger the matric suction;the higher the moisture content,the lower the matric suction.Under the same moisture content,the matric suction increases with the confining pressure and reaches a maximum when the confining pressure is 100 kPa,and then decreases with the increase of confining pressure.This phenomenon is closely related to the grain contact tightness of soil mass under high confining pressure.According to the triaxial test of loess,the sample of loess experiences 4 stages from loading to failure:1) compaction stage;2) compression stage;3) microcrack developing stage;4) shear failure stage.The test sample is of brittle failure(weak softening)under low moisture content and confining pressure.With the decrease of matric suction and the increase of consolidated confining pressure,the stress-strain curve changes from softening type to ideal plastic type.In the shearing strength parameters of unsaturated undisturbed loess,the influence of moisture content on internal friction angle is small,but that on cohesive force is obvious.Therefore,the shearing strength of unsaturated undisturbed loess is higher than that of saturated undisturbed loess and varies with the moisture content.展开更多
Through the usage of simulation software based on the network layout, airway resistances and parameters of main fans, ventilation calculations were performed to analyse the current situation as a ventilation wall buil...Through the usage of simulation software based on the network layout, airway resistances and parameters of main fans, ventilation calculations were performed to analyse the current situation as a ventilation wall built in No.1 west airway to separate the two subsystems. A comparison of simulation results and in-site measurements show that the maximum deviation is less than 10%. Further calculations for the case that the ventilation wall in No.1 west airwav is removed to consider the consequences when the two subsystems are merged together. Results of the simulation showthat the total airflow rate increases, and the ventilation resistance of the mine decreases in comparing with that of the foregoing simulation.展开更多
The Spurge family （Euphorbiaceae） is a large family of flowering plants. Two plant species of this family were collected from the Egyptian desert, extracted with methanol subjected to silica gel column chromatograph...The Spurge family （Euphorbiaceae） is a large family of flowering plants. Two plant species of this family were collected from the Egyptian desert, extracted with methanol subjected to silica gel column chromatography to give six compounds, three compounds from each plant. The compounds isolated from the methanol extract of Euphorbia retusa Forssk were identified as kaempferol-3-beta-D glucopyranosyl （1）, 3-O-alpha-L-xylopyranosyl （1→3）-alpha-L xylopyranosyl （1→2）, beta-D glucopyranosyllup 1,12-diene-3,21-diol （2） and 5,7,8,3＇,4＇-pentahydroxy-3-methoxyflavone （3） and the compounds isolated from Euphorbia paralais L. identified as 3,5,3＇-trihydroxy-6,7-d-methoxy-4＇ （7＂-hydroxygeranyl-1＂-ether） flavones （4）, 3-O-syringic acid （1→4）-alpha-L- xylopyranosyl （1→3）, beta-D-rahminopyranosyl hederagenin （5） and 3-O-syringic acid （1→4）, beta-D-rahminopyranosyl （1→3）,beta-D-rahminopyranosyl hederagenin （6）. The structure of the isolated compounds was elucidated by chemical and spectrometric analysis such as Infera red （IR）, proton and carbon nuclear magnetic resonance （1H-, 13C-NMR） and chemical ionization mass spectrometry （CI-MS）.展开更多
基金Project(50621063)supported by the National Natural Science Foundation of ChinaProject(2004CD619205)supported by the Major StateBasic Research Development Program of China
文摘Elective culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in 9K medium modified with pyrrhotite was studied.Bioleaching of flotation concentrate of sphalerite by the selected bacteria was carried out.The results show that the microorganisms cultured by pyrrhotite are a mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans,of which the capability to oxidize ferrous to ferric irons is enhanced by the high mass ratio of Fe to S in pyrrhotite.Three pyrrhotite samples were separated into various parts with corresponding S/Fe ratios by magnetic separation and were used to culture the elective bacteria as the substrate.The association of the cultures could provide a more rapid and complete oxidation of sphalerite than that of bacteria cultivated by conventional methods.
基金Supported by the State Ministry of Science and Technology of China (Nos.2007AA09Z118,2008AA09A402)the National Natural Science Foundation of China(No.41076006)the Ministry of Education's 111 Project(No.B07036)
文摘Two-dimensional tidal open boundary conditions of the M2 constituent in the Bohai and Yellow Seas(BYS) have been estimated by assimilating T/P altimeter data.During inversion,independent point(IP) strategy was used,in which several IPs on the open boundary is assumed,values at these IPs can be optimized with an adjoint method,and those at other grid points are determined by linearly interpolating the values at IPs.The reasonability and feasibility of the model are tested by ideal twin experiments.In the practical experiment(PE) after assimilation,the cost function may reach 1% or less of its initial value.Mean absolute errors in amplitude and phase can be less than 5 cm and 5°,respectively,and the obtained co-chart can show the character of the M2 constituent in the BYS.The results of the PE indicate that using only two IPs on the open boundary can yield better simulated results.
文摘This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village houses. The stratum structure control action of mining subsidence was used to design the mining and pillar width. To further raise resources recovery, we adopted the mutative scheme of mining and pillar width. Observation was carried out while mining. Research shows there is feasibility of the strip mining technology to protecting the village buildings of the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. Finally, subsidence parameters of strip mining were obtained. It is the basic data of the strip mining of the coal field at the north of the Yellow River.
基金Project(51108485)supported by the National Natural Science Foundation of ChinaProject(20110191120033)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China+1 种基金Projects(106112013CDJZR200001,CDJZR12200012)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(cstc2013jcyjA30005)supported by the Natural Science Foundation of Chongqing,China
文摘The unsaturated undisturbed quaternary system middle pleistocene loess,a typical unsaturated soil,often occurs in the implementation of western development strategy.To obtain the shearing strength characteristics of this unsaturated undisturbed loess,based on the analysis of mineral composition,the triaxial shear test of undisturbed quaternary system middle pleistocene loess under different moisture contents is conducted with the specialized triaxial instrument for unsaturated soil.The test results show that the mainly mineral composition of undisturbed quaternary system middle pleistocene loess is quartz and albite.Under the same confining pressure,the matric suction increases with the decrease of moisture content.The smaller the moisture content,the larger the matric suction;the higher the moisture content,the lower the matric suction.Under the same moisture content,the matric suction increases with the confining pressure and reaches a maximum when the confining pressure is 100 kPa,and then decreases with the increase of confining pressure.This phenomenon is closely related to the grain contact tightness of soil mass under high confining pressure.According to the triaxial test of loess,the sample of loess experiences 4 stages from loading to failure:1) compaction stage;2) compression stage;3) microcrack developing stage;4) shear failure stage.The test sample is of brittle failure(weak softening)under low moisture content and confining pressure.With the decrease of matric suction and the increase of consolidated confining pressure,the stress-strain curve changes from softening type to ideal plastic type.In the shearing strength parameters of unsaturated undisturbed loess,the influence of moisture content on internal friction angle is small,but that on cohesive force is obvious.Therefore,the shearing strength of unsaturated undisturbed loess is higher than that of saturated undisturbed loess and varies with the moisture content.
文摘Through the usage of simulation software based on the network layout, airway resistances and parameters of main fans, ventilation calculations were performed to analyse the current situation as a ventilation wall built in No.1 west airway to separate the two subsystems. A comparison of simulation results and in-site measurements show that the maximum deviation is less than 10%. Further calculations for the case that the ventilation wall in No.1 west airwav is removed to consider the consequences when the two subsystems are merged together. Results of the simulation showthat the total airflow rate increases, and the ventilation resistance of the mine decreases in comparing with that of the foregoing simulation.
文摘The Spurge family （Euphorbiaceae） is a large family of flowering plants. Two plant species of this family were collected from the Egyptian desert, extracted with methanol subjected to silica gel column chromatography to give six compounds, three compounds from each plant. The compounds isolated from the methanol extract of Euphorbia retusa Forssk were identified as kaempferol-3-beta-D glucopyranosyl （1）, 3-O-alpha-L-xylopyranosyl （1→3）-alpha-L xylopyranosyl （1→2）, beta-D glucopyranosyllup 1,12-diene-3,21-diol （2） and 5,7,8,3＇,4＇-pentahydroxy-3-methoxyflavone （3） and the compounds isolated from Euphorbia paralais L. identified as 3,5,3＇-trihydroxy-6,7-d-methoxy-4＇ （7＂-hydroxygeranyl-1＂-ether） flavones （4）, 3-O-syringic acid （1→4）-alpha-L- xylopyranosyl （1→3）, beta-D-rahminopyranosyl hederagenin （5） and 3-O-syringic acid （1→4）, beta-D-rahminopyranosyl （1→3）,beta-D-rahminopyranosyl hederagenin （6）. The structure of the isolated compounds was elucidated by chemical and spectrometric analysis such as Infera red （IR）, proton and carbon nuclear magnetic resonance （1H-, 13C-NMR） and chemical ionization mass spectrometry （CI-MS）.
