Diffusion tensor imaging was performed in 105 volunteers free of central nervous system lesions.No differences were found in fractional anisotropy between the left and right cerebral peduncles among subjects（P 0.05）...Diffusion tensor imaging was performed in 105 volunteers free of central nervous system lesions.No differences were found in fractional anisotropy between the left and right cerebral peduncles among subjects（P 0.05）.The lower limit value of fractional anisotropy was 0.36,and the asymmetry ratio was 0.77.The area and lower limit value of the cerebral peduncles were 0.90 cm2 and 0.83,respectively.These results will be useful in evaluating the diagnosis of Wallerian degeneration following cerebral infarction.展开更多
Refractive index matching(RIM)is widely used to investigate particle-liquid mixture flows.However,determining the volume fractionφin RIM is generally empirical and lacks theoretical or experimental basis.To reasonabl...Refractive index matching(RIM)is widely used to investigate particle-liquid mixture flows.However,determining the volume fractionφin RIM is generally empirical and lacks theoretical or experimental basis.To reasonably reconstruct the internalφ,this study performs systematic calibration experiments to study the relationship betweenφand the imaging indicators.The results show that the model based on area fraction c2D will induce a large error for lowφowing to the instability of the particle’s apparent size.The traditionally adopted proportional functionφ=ac2D is only valid forφnear the calibration point.A predictive model is proposed based on the size of the Voronoi cell,dpoly,which proves to be more accurate and stable in RIM experiments.The dpoly-based model is applied to dense granular flows down an inclined plane to study the internal profiles ofφand the bottom normal stress.展开更多
The aim of the present work is to investigate the distribution of arsenic（As） in sewage ir-rigation area,to deduce the migration and transformation mechanism of As in soil and groundwater,and to infer the source of ...The aim of the present work is to investigate the distribution of arsenic（As） in sewage ir-rigation area,to deduce the migration and transformation mechanism of As in soil and groundwater,and to infer the source of As in soil and groundwater.This study is carried out in a sewage irrigation area of the Pearl River Delta,China.Surface water samples,soil samples,and groundwater samples from sewage irrigation area were analyzed for As and other elements.As contents in water samples were analyzed by hydride generation-atomic fluorescence spectroscopy,and As fractionation in soil samples was extracted using a seven-step sequential extraction method according to a seven fraction scheme：water soluble,ion exchangeable,bound to carbonate,weakly bound to organic matter,associ-ated with oxides of iron（Fe） and manganese（Mn）,strongly bound to organic matter,and the residual fraction.Waste water has content of As up to 16.8 μg/L in the study area.Soil has enriched As due to the irrigation of soil with waste water,and the total content of As in soil is about 0.7 times higher than the background value.Sequential extraction method reveals that the mean content of residual fraction in soil is more than 70%,releasable fraction（weakly organic fraction,Fe-Mn oxide fraction,and car-bonate fraction） is about 20%-30%,whereas strongly organic and mobile fractions（water soluble and ion exchangeable） are within 0.2%.In the soil profile,the contents of water soluble,ion exchangeable,and carbonate fraction decrease with the depth,whereas the contents of other fractions are irregular with the depth.Using correlation analysis,it is concluded that water soluble fraction is easy to change into ion exchangeable and carbonate fraction,ion exchangeable fraction is easy to change into carbon-ate and Fe-Mn oxide fraction,and carbonate fraction is easy to change into weakly organic and Fe-Mn oxide fraction in the soil of study area.Organic matter and（hydr）oxides of Fe and aluminium（Al） in soil play an important role in controlling the distribution and mobility of As in soil.As concentrations in groundwater range from 2.8 to 21.0 μg/L,and it is inferred that As from waste water and the release of high As sediment（soil and aquifer medium） are the main sources for high As groundwater in study area.Using cluster analysis,it is concluded that reducing ground-water with slightly alkaline is beneficial to en-richment of As in groundwater,and hydroxides of Fe,Mn,and Al also play a key role for the en-richment of As in groundwater of the study area.展开更多
The Mazhuangshan area lies in northeast to Aqikekuduke, where are distributed intermediate\|acid rocks, which were formed in the Middle\|Late Carboniferous epoch. The magmatic rocks are peraluminous and belong to calc...The Mazhuangshan area lies in northeast to Aqikekuduke, where are distributed intermediate\|acid rocks, which were formed in the Middle\|Late Carboniferous epoch. The magmatic rocks are peraluminous and belong to calcareous series. All values of ACNK(1.03-\{2.12\}), ANK(1.67-2.93), SI(4.1-33), δ(0.71-4.82), La/ΣREE(0.09-0.26) ΣLREE/ΣHREE(1.76-11.01), (La/Sm)\-N(1.60-6.35), (Sm/Nd)\-N(0.33-0.58), (La/Yb)\-N(4.7-12.1), La\-N/Lu\-X(5.9-11.8), (Ce/Yb)\-N(3.14-6.64), δEu(0.38-\{1.06\}), Rb\-N/Sr\-N(42-120) and Sr\+*(0.02-0.2) demonstrate they vary with DI(\{45-90\}). S\|B diagram also shows that the lithophile elements are abundant in acidic magmatic rocks. Moreover, it is concluded that the primitive magma originated from a subduction zone at the continental edge, and underwent fractional crystallization and contamination, then generated the magmatic rocks. The multi\|cation index (R1: 3055-3993, R2: 286-438) shows that the primitive magma originated from the mantle. All these conclusions are beneficial for exploring gold deposits in the area.展开更多
This paper investigates the effect of launching multiple weapons against an area target of normally distributed elements. We provide an analytical form of the average damage fraction and then apply it to obtain optima...This paper investigates the effect of launching multiple weapons against an area target of normally distributed elements. We provide an analytical form of the average damage fraction and then apply it to obtain optimal aimpoints. To facilitate the computational efforts in practice, we also consider optimizations over given constrained patterns of aimpoints. Finally, we derive scaling laws for optimal aimpoints and optimal damage fraction with respect to the radius of the area target.展开更多
以浙江石化180万t/a S Zorb催化汽油吸附脱硫装置为例,对该装置分馏区和罐区管道、设备布置要点进行分析,包括管口方位的确定、塔顶安全阀管道布置、泵的布置、分馏构架(空冷器、稳定塔顶后冷却器、稳定塔回流罐等设备)布置以及地下污...以浙江石化180万t/a S Zorb催化汽油吸附脱硫装置为例,对该装置分馏区和罐区管道、设备布置要点进行分析,包括管口方位的确定、塔顶安全阀管道布置、泵的布置、分馏构架(空冷器、稳定塔顶后冷却器、稳定塔回流罐等设备)布置以及地下污油罐埋深计算等方面,为今后S Zorb装置配管设计提供了可借鉴的设计经验。展开更多
基金the grant of Science and Technology Bureau of Zhongshan, No. 20102C146
文摘Diffusion tensor imaging was performed in 105 volunteers free of central nervous system lesions.No differences were found in fractional anisotropy between the left and right cerebral peduncles among subjects（P 0.05）.The lower limit value of fractional anisotropy was 0.36,and the asymmetry ratio was 0.77.The area and lower limit value of the cerebral peduncles were 0.90 cm2 and 0.83,respectively.These results will be useful in evaluating the diagnosis of Wallerian degeneration following cerebral infarction.
基金the National Natural Science Foundation of China(Grant Nos.12032005 and 12172057)。
文摘Refractive index matching(RIM)is widely used to investigate particle-liquid mixture flows.However,determining the volume fractionφin RIM is generally empirical and lacks theoretical or experimental basis.To reasonably reconstruct the internalφ,this study performs systematic calibration experiments to study the relationship betweenφand the imaging indicators.The results show that the model based on area fraction c2D will induce a large error for lowφowing to the instability of the particle’s apparent size.The traditionally adopted proportional functionφ=ac2D is only valid forφnear the calibration point.A predictive model is proposed based on the size of the Voronoi cell,dpoly,which proves to be more accurate and stable in RIM experiments.The dpoly-based model is applied to dense granular flows down an inclined plane to study the internal profiles ofφand the bottom normal stress.
基金supported by the National Basic Research Program (973) of China (No. 2010CB428804-1)the Basic Scientific Study Fund from the Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sci-ences (Nos. SK200801, SK200911)
文摘The aim of the present work is to investigate the distribution of arsenic（As） in sewage ir-rigation area,to deduce the migration and transformation mechanism of As in soil and groundwater,and to infer the source of As in soil and groundwater.This study is carried out in a sewage irrigation area of the Pearl River Delta,China.Surface water samples,soil samples,and groundwater samples from sewage irrigation area were analyzed for As and other elements.As contents in water samples were analyzed by hydride generation-atomic fluorescence spectroscopy,and As fractionation in soil samples was extracted using a seven-step sequential extraction method according to a seven fraction scheme：water soluble,ion exchangeable,bound to carbonate,weakly bound to organic matter,associ-ated with oxides of iron（Fe） and manganese（Mn）,strongly bound to organic matter,and the residual fraction.Waste water has content of As up to 16.8 μg/L in the study area.Soil has enriched As due to the irrigation of soil with waste water,and the total content of As in soil is about 0.7 times higher than the background value.Sequential extraction method reveals that the mean content of residual fraction in soil is more than 70%,releasable fraction（weakly organic fraction,Fe-Mn oxide fraction,and car-bonate fraction） is about 20%-30%,whereas strongly organic and mobile fractions（water soluble and ion exchangeable） are within 0.2%.In the soil profile,the contents of water soluble,ion exchangeable,and carbonate fraction decrease with the depth,whereas the contents of other fractions are irregular with the depth.Using correlation analysis,it is concluded that water soluble fraction is easy to change into ion exchangeable and carbonate fraction,ion exchangeable fraction is easy to change into carbon-ate and Fe-Mn oxide fraction,and carbonate fraction is easy to change into weakly organic and Fe-Mn oxide fraction in the soil of study area.Organic matter and（hydr）oxides of Fe and aluminium（Al） in soil play an important role in controlling the distribution and mobility of As in soil.As concentrations in groundwater range from 2.8 to 21.0 μg/L,and it is inferred that As from waste water and the release of high As sediment（soil and aquifer medium） are the main sources for high As groundwater in study area.Using cluster analysis,it is concluded that reducing ground-water with slightly alkaline is beneficial to en-richment of As in groundwater,and hydroxides of Fe,Mn,and Al also play a key role for the en-richment of As in groundwater of the study area.
文摘The Mazhuangshan area lies in northeast to Aqikekuduke, where are distributed intermediate\|acid rocks, which were formed in the Middle\|Late Carboniferous epoch. The magmatic rocks are peraluminous and belong to calcareous series. All values of ACNK(1.03-\{2.12\}), ANK(1.67-2.93), SI(4.1-33), δ(0.71-4.82), La/ΣREE(0.09-0.26) ΣLREE/ΣHREE(1.76-11.01), (La/Sm)\-N(1.60-6.35), (Sm/Nd)\-N(0.33-0.58), (La/Yb)\-N(4.7-12.1), La\-N/Lu\-X(5.9-11.8), (Ce/Yb)\-N(3.14-6.64), δEu(0.38-\{1.06\}), Rb\-N/Sr\-N(42-120) and Sr\+*(0.02-0.2) demonstrate they vary with DI(\{45-90\}). S\|B diagram also shows that the lithophile elements are abundant in acidic magmatic rocks. Moreover, it is concluded that the primitive magma originated from a subduction zone at the continental edge, and underwent fractional crystallization and contamination, then generated the magmatic rocks. The multi\|cation index (R1: 3055-3993, R2: 286-438) shows that the primitive magma originated from the mantle. All these conclusions are beneficial for exploring gold deposits in the area.
文摘This paper investigates the effect of launching multiple weapons against an area target of normally distributed elements. We provide an analytical form of the average damage fraction and then apply it to obtain optimal aimpoints. To facilitate the computational efforts in practice, we also consider optimizations over given constrained patterns of aimpoints. Finally, we derive scaling laws for optimal aimpoints and optimal damage fraction with respect to the radius of the area target.
文摘以浙江石化180万t/a S Zorb催化汽油吸附脱硫装置为例,对该装置分馏区和罐区管道、设备布置要点进行分析,包括管口方位的确定、塔顶安全阀管道布置、泵的布置、分馏构架(空冷器、稳定塔顶后冷却器、稳定塔回流罐等设备)布置以及地下污油罐埋深计算等方面,为今后S Zorb装置配管设计提供了可借鉴的设计经验。
