G804.4 9903346不同类型负荷对人体骨密度影响的研究=The effectsof the different type’s load on the bone densityof the human body[刊,中,I]/王小燕∥湖北体育科技.-1999.-18(1).-55-58表5参3(YYW)骨∥密度∥负荷∥矿物质∥含量...G804.4 9903346不同类型负荷对人体骨密度影响的研究=The effectsof the different type’s load on the bone densityof the human body[刊,中,I]/王小燕∥湖北体育科技.-1999.-18(1).-55-58表5参3(YYW)骨∥密度∥负荷∥矿物质∥含量∥前臂∥骨皮质对举重、中长跑和不从事任何专项运动(对照组)各30名男青年的前臂骨进行了观察测定,并对三组青年的前臂桡、尺骨骨皮质、骨髓腔、骨矿含量和骨密度等进行了统计分析。结果表明:桡。展开更多
The electronic properties of sphalerite(110)surface bearing Fe,Mn and Cd impurities were calculated using density-functional theory,and the effects of impurities on the copper activation of sphalerite were investigate...The electronic properties of sphalerite(110)surface bearing Fe,Mn and Cd impurities were calculated using density-functional theory,and the effects of impurities on the copper activation of sphalerite were investigated.Calculated results indicate that both Fe and Mn impurities narrow the band gap of sphalerite surface and lead to the Fermi level shifting to conduction band.Impurity levels composed of Fe 3d and Mn 3d orbital appearing in band gap are beneficial to electrons transfer from the valence band to the conduction band and promote the surface conductivity and the electrochemical activity.The results show that Fe and Mn impurities cannot be replaced by Cu atom,which reduces the exchange sites(Zn)for Cu atom,hence Fe-and Mn-bearing sphalerites are hard to be activated by copper.Cd impurity has little effect on electronic structure of sphalerite surface;however,Cd atom is easily replaced by Cu atom,and this is the reason why the Cd-bearing sphalerite can be easily floated.展开更多
We used data from bottom trawl surveys to study the factors influencing the abundance of small yellow croaker, Larimichthys polyactis, in the southern Yellow Sea （SYS） and the East China Sea （ECS）. The resource de...We used data from bottom trawl surveys to study the factors influencing the abundance of small yellow croaker, Larimichthys polyactis, in the southern Yellow Sea （SYS） and the East China Sea （ECS）. The resource density index （RD1） was generally higher in summer and autumn than in spring and winter. RDIs were also significantly greater in the SYS than in the ECS in summer and autumn. The bottom water salinity and depth of spatial distribution of small yellow croaker was similar between the two areas in summer, but different in other seasons. Regression analysis suggested that environmental factors such as bottom water temperature, salinity, and depth influenced the RDIs in summer in these areas. Growth condition factor （GCF） in the two areas varied monthly and the croaker in the SYS grew more slowly than those in the ECS. This was likely due to the low bottom temperature of the Yellow Sea Cold Water Mass in summer and autumn or to higher human fishing pressure in the ECS. To ensure sustainable utilization of the croaker stocks in these regions, we recommend reducing the fishing intensity, increasing the cod-end mesh size, and improving the protection of juveniles.展开更多
Declining soil fertility has become an increasingly urgent problem and gathering firewood is one of the important contributing factors.Due to the excessive exploitation of natural resources especially for firewood,the...Declining soil fertility has become an increasingly urgent problem and gathering firewood is one of the important contributing factors.Due to the excessive exploitation of natural resources especially for firewood,the red soil hilly region has become one of the most vulnerable eco-environment regions in China.The pressure of gathering firewood on forestland soil fertility in forestland has been generally estimated by geographical information system and questionnaire method in this paper in the Zhuxi watershed of Changting County,Fujian Province,China,a typical representative in the red soil hilly region of China.The results of this study show that：i） Forestland soil fertility is negatively affected by gathering firewood,which is more intensive in the integrated buffer zone than out of zone.The forestland soil fertility grade,OM,total N,available N,total P,available P,total K,available K,pH and ＆lt;2μm clay content are lower and bulk density is higher in the integrated buffer zone than those out.ii） The forestland soil fertility grade,OM,total N,available N,total P,available P,total K,available K,pH and ＆lt;2μm clay content tend to be lower and bulk density tends to be higher in the village buffer zones than those out in Datian,Chenguang and Youfang respectively.iii） The population density,economic development and terrain might be the key driving forces contributing to the relationship between gathering firewood and forestland soil fertility.Higher population density leads to more massive firewood collection and imposes more pressure on forestland soil fertility.Decreasing the use of firewood stove may reduce firewood consumption and thus release the pressure of gathering firewood on forestland soil fertility.Terrain affects the accessibility to gathering firewood thus affects forestland soil fertility.Other driving forces influencing the relationship between gathering firewood and forestland soil fertility should also be taken into account in the further study.展开更多
文摘G804.4 9903346不同类型负荷对人体骨密度影响的研究=The effectsof the different type’s load on the bone densityof the human body[刊,中,I]/王小燕∥湖北体育科技.-1999.-18(1).-55-58表5参3(YYW)骨∥密度∥负荷∥矿物质∥含量∥前臂∥骨皮质对举重、中长跑和不从事任何专项运动(对照组)各30名男青年的前臂骨进行了观察测定,并对三组青年的前臂桡、尺骨骨皮质、骨髓腔、骨矿含量和骨密度等进行了统计分析。结果表明:桡。
基金Project(50864001) supported by the National Natural Science Foundation of China
文摘The electronic properties of sphalerite(110)surface bearing Fe,Mn and Cd impurities were calculated using density-functional theory,and the effects of impurities on the copper activation of sphalerite were investigated.Calculated results indicate that both Fe and Mn impurities narrow the band gap of sphalerite surface and lead to the Fermi level shifting to conduction band.Impurity levels composed of Fe 3d and Mn 3d orbital appearing in band gap are beneficial to electrons transfer from the valence band to the conduction band and promote the surface conductivity and the electrochemical activity.The results show that Fe and Mn impurities cannot be replaced by Cu atom,which reduces the exchange sites(Zn)for Cu atom,hence Fe-and Mn-bearing sphalerites are hard to be activated by copper.Cd impurity has little effect on electronic structure of sphalerite surface;however,Cd atom is easily replaced by Cu atom,and this is the reason why the Cd-bearing sphalerite can be easily floated.
基金Supported by the National Natural Science Foundation of China for Creative Research Groups (No. 40821004)the National Key Technology Research and Development Program (No. 2007BAD43B01)the Open Fund of Key Laboratory of Marine Ecology and Environmental Science, Institute of Oceanology, Chinese Academy of Sciences (No. KLMEES201001)
文摘We used data from bottom trawl surveys to study the factors influencing the abundance of small yellow croaker, Larimichthys polyactis, in the southern Yellow Sea （SYS） and the East China Sea （ECS）. The resource density index （RD1） was generally higher in summer and autumn than in spring and winter. RDIs were also significantly greater in the SYS than in the ECS in summer and autumn. The bottom water salinity and depth of spatial distribution of small yellow croaker was similar between the two areas in summer, but different in other seasons. Regression analysis suggested that environmental factors such as bottom water temperature, salinity, and depth influenced the RDIs in summer in these areas. Growth condition factor （GCF） in the two areas varied monthly and the croaker in the SYS grew more slowly than those in the ECS. This was likely due to the low bottom temperature of the Yellow Sea Cold Water Mass in summer and autumn or to higher human fishing pressure in the ECS. To ensure sustainable utilization of the croaker stocks in these regions, we recommend reducing the fishing intensity, increasing the cod-end mesh size, and improving the protection of juveniles.
基金funded by the National Natural Science Foundation of China (Grant Nos.40871141,41001170,41171232)
文摘Declining soil fertility has become an increasingly urgent problem and gathering firewood is one of the important contributing factors.Due to the excessive exploitation of natural resources especially for firewood,the red soil hilly region has become one of the most vulnerable eco-environment regions in China.The pressure of gathering firewood on forestland soil fertility in forestland has been generally estimated by geographical information system and questionnaire method in this paper in the Zhuxi watershed of Changting County,Fujian Province,China,a typical representative in the red soil hilly region of China.The results of this study show that：i） Forestland soil fertility is negatively affected by gathering firewood,which is more intensive in the integrated buffer zone than out of zone.The forestland soil fertility grade,OM,total N,available N,total P,available P,total K,available K,pH and ＆lt;2μm clay content are lower and bulk density is higher in the integrated buffer zone than those out.ii） The forestland soil fertility grade,OM,total N,available N,total P,available P,total K,available K,pH and ＆lt;2μm clay content tend to be lower and bulk density tends to be higher in the village buffer zones than those out in Datian,Chenguang and Youfang respectively.iii） The population density,economic development and terrain might be the key driving forces contributing to the relationship between gathering firewood and forestland soil fertility.Higher population density leads to more massive firewood collection and imposes more pressure on forestland soil fertility.Decreasing the use of firewood stove may reduce firewood consumption and thus release the pressure of gathering firewood on forestland soil fertility.Terrain affects the accessibility to gathering firewood thus affects forestland soil fertility.Other driving forces influencing the relationship between gathering firewood and forestland soil fertility should also be taken into account in the further study.
