Soil infiltration capability is the hot spot topic of soil erosion studies and soil physical and chemical properties have great influence on it. A new infiltration method point- source infiltration method was used to ...Soil infiltration capability is the hot spot topic of soil erosion studies and soil physical and chemical properties have great influence on it. A new infiltration method point- source infiltration method was used to precisely evaluate the infiltration capability in different purple soil land- use types. And correlation analysis on soil physical and chemical properties and soil infiltration capability of different land- use types was performed. Results showed that:( i) there is a large difference among soil physical and chemical properties in different land- use types,soil water content,non- capillary porosity,capillary porosity,content of > 0. 25 mm aggregates and organic matter content in the top soil are greater than those in the subsoil;( ii) soil infiltration capability showed differences among different land- use types. Land use showed great effects,in general,the order of decrease on initial infiltration rate and average infiltration rate was: woodland slope > slope farmland >grassland,the order of decrease on steady infiltration rate was: slope farmland > woodland > grassland and the time reaching stable state was:slope farmland > woodland > grassland;( iii) correlation analysis showed that there was a significantly positive correlation between initial infiltration rate and wet sieve MWD value and structural damage rate,and it had a significantly negative correlation with capillary porosity;( iv)steady infiltration rate and non- capillary porosity showed the significantly positive correlation,and it had a significantly negative correlation with the soil bulk density;( v) the average infiltration rate and non- capillary porosity and structural damage rate showed a positive correlation and the correlation coefficient was large and there was a negative correlation between average infiltration rate and soil bulk density and capillary porosity,and the absolute value of correlation coefficient was relatively large. The results of this study can provide the theoretical basis for soil infiltration study in purple soil area.展开更多
While there have been multiple recent reports in the literature focusing on the effects of magnetic field on the phase transformation behaviors,the research conducted with an ultra-high magnetic field greater than 20 ...While there have been multiple recent reports in the literature focusing on the effects of magnetic field on the phase transformation behaviors,the research conducted with an ultra-high magnetic field greater than 20 T is still preliminary.In the current study,the structure evolution of Co-B alloys are experimentally studied with undercooling.The effects of a 25 T magnetic field on the solidification behavior and the subsequent solid-state phase transformation behavior have been investigated.The 25 T magnetic field is confirmed to have little effect on the homogeneous nucleation,but have some influence on the heterogeneous nucleation of Co_(3) B and Co_(23)B6 phases by modifying the wetting angleθ.The decomposition of Co_(23)B6 phase in the subsequent cooling process can be effectively suppressed by applying the 25 T magnetic field.The present work might be helpful for not only theoretically understanding the influence of ultra-high magnetic field on the phase transformation behaviors but a potential technology of field-manipulation of magnetic materials.展开更多
In China, although improvements to the pesticide registration process have been made in la thirty years, no occupational exposure data are required to obtain a commercial license for pesticide product. Consequently, n...In China, although improvements to the pesticide registration process have been made in la thirty years, no occupational exposure data are required to obtain a commercial license for pesticide product. Consequently, notably little research has been conducted to establish a exposure assessment procedure in China. The present study monitored the potential derm operator exposure from knapsack electric sprayer wheat field application of imidacloprid Liaocheng City, Shandong Province and in Xinxiang City, Henan Province, China, usin whole-body dosimetry. The potential inhalation exposure was determined using a person air pump and XAD-2 sample tubes. The analytical method was developed and validate including such performance parameters as limits of detection and quantification, linear rang recovery and precision. The total potential dermal and inhalation exposures were 14.20, 16.815.39 and 20.78 mL/hr, respectively, for the four operators in Liaocheng and Xinxian corresponding to 0.02% to 0.03% of the applied volume of spray solution. In all trials, the low part(thigh, lower leg) of the body was the most contaminated, accounting for approximate76% to 88% of the total exposure. The inhalation exposure was less than 1% of the tot exposure. Such factors as the application pattern, crop type, spray equipment, operat experience and climatic conditions have been used to explain the exposure distribution ov the different parts of the body. As indicated by the calculated Margin of Exposure, the typic wheat treatment scenarios when a backpack sprayer was used are considered to be safe terms of imidacloprid exposure.展开更多
基金Supported by National Science and Technology Support Program(2011BAD31B03)Fundamental Research Funds for Central Universities(XDJK2011C013)
文摘Soil infiltration capability is the hot spot topic of soil erosion studies and soil physical and chemical properties have great influence on it. A new infiltration method point- source infiltration method was used to precisely evaluate the infiltration capability in different purple soil land- use types. And correlation analysis on soil physical and chemical properties and soil infiltration capability of different land- use types was performed. Results showed that:( i) there is a large difference among soil physical and chemical properties in different land- use types,soil water content,non- capillary porosity,capillary porosity,content of > 0. 25 mm aggregates and organic matter content in the top soil are greater than those in the subsoil;( ii) soil infiltration capability showed differences among different land- use types. Land use showed great effects,in general,the order of decrease on initial infiltration rate and average infiltration rate was: woodland slope > slope farmland >grassland,the order of decrease on steady infiltration rate was: slope farmland > woodland > grassland and the time reaching stable state was:slope farmland > woodland > grassland;( iii) correlation analysis showed that there was a significantly positive correlation between initial infiltration rate and wet sieve MWD value and structural damage rate,and it had a significantly negative correlation with capillary porosity;( iv)steady infiltration rate and non- capillary porosity showed the significantly positive correlation,and it had a significantly negative correlation with the soil bulk density;( v) the average infiltration rate and non- capillary porosity and structural damage rate showed a positive correlation and the correlation coefficient was large and there was a negative correlation between average infiltration rate and soil bulk density and capillary porosity,and the absolute value of correlation coefficient was relatively large. The results of this study can provide the theoretical basis for soil infiltration study in purple soil area.
基金supported by the National Natural Science Foundation of China(No.51690164)the fund of National Key Laboratory for Precision Hot Processing of Metals(6142909200104)+2 种基金National Training Program of Innovation and Entrepreneurship for Undergraduates(S202010699137)the Fundamental Research Funds for the Central Universitiesthe support of the LNCMI-CNRS。
文摘While there have been multiple recent reports in the literature focusing on the effects of magnetic field on the phase transformation behaviors,the research conducted with an ultra-high magnetic field greater than 20 T is still preliminary.In the current study,the structure evolution of Co-B alloys are experimentally studied with undercooling.The effects of a 25 T magnetic field on the solidification behavior and the subsequent solid-state phase transformation behavior have been investigated.The 25 T magnetic field is confirmed to have little effect on the homogeneous nucleation,but have some influence on the heterogeneous nucleation of Co_(3) B and Co_(23)B6 phases by modifying the wetting angleθ.The decomposition of Co_(23)B6 phase in the subsequent cooling process can be effectively suppressed by applying the 25 T magnetic field.The present work might be helpful for not only theoretically understanding the influence of ultra-high magnetic field on the phase transformation behaviors but a potential technology of field-manipulation of magnetic materials.
基金supported by the State Key Development Program for Basic Research of China (No. 2014CB932204)the Special Fund for Agro-Scientific Research in the Public Interest of China (No. 200903054)
文摘In China, although improvements to the pesticide registration process have been made in la thirty years, no occupational exposure data are required to obtain a commercial license for pesticide product. Consequently, notably little research has been conducted to establish a exposure assessment procedure in China. The present study monitored the potential derm operator exposure from knapsack electric sprayer wheat field application of imidacloprid Liaocheng City, Shandong Province and in Xinxiang City, Henan Province, China, usin whole-body dosimetry. The potential inhalation exposure was determined using a person air pump and XAD-2 sample tubes. The analytical method was developed and validate including such performance parameters as limits of detection and quantification, linear rang recovery and precision. The total potential dermal and inhalation exposures were 14.20, 16.815.39 and 20.78 mL/hr, respectively, for the four operators in Liaocheng and Xinxian corresponding to 0.02% to 0.03% of the applied volume of spray solution. In all trials, the low part(thigh, lower leg) of the body was the most contaminated, accounting for approximate76% to 88% of the total exposure. The inhalation exposure was less than 1% of the tot exposure. Such factors as the application pattern, crop type, spray equipment, operat experience and climatic conditions have been used to explain the exposure distribution ov the different parts of the body. As indicated by the calculated Margin of Exposure, the typic wheat treatment scenarios when a backpack sprayer was used are considered to be safe terms of imidacloprid exposure.