针对小流域暴雨洪水预报难的问题,利用模块化小流域暴雨洪水预报FFMS(Flash Flood Modul Simulation System)模型和HEC-HMS(Hydrologic Engineering Center Hydrological Model System)模型,以河南栾川、韩城及辽宁郝家店、梨庇峪4个山...针对小流域暴雨洪水预报难的问题,利用模块化小流域暴雨洪水预报FFMS(Flash Flood Modul Simulation System)模型和HEC-HMS(Hydrologic Engineering Center Hydrological Model System)模型,以河南栾川、韩城及辽宁郝家店、梨庇峪4个山丘区小流域为例,对比分析了4个流域的暴雨洪水预报过程,以洪峰相对误差、峰现时间误差以及纳什系数等为评价准则,比较和分析了2个模型的预报精度和适用性。实例验证结果表明:虽然2种模型均能实现小流域暴雨洪水的预报,但从3个评价准则的结果来看,FFMS模型的预报精度优于HEC-HMS模型。研究成果证明了FFMS模型在山丘区小流域暴雨洪水预报中的有效性和可行性,可以在类似山丘区小流域暴雨洪水预报中进行推广应用。展开更多
A novel super-hydrophobic stearic acid(STA)film with a water contact angle of 166° was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine(PEI)film. The micro-tribological behavior of ...A novel super-hydrophobic stearic acid(STA)film with a water contact angle of 166° was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine(PEI)film. The micro-tribological behavior of the super-hydrophobic STA monolayer was compared with that of the polished and PEI-coated Al surfaces.The effect of relative humidity on the adhesion and friction was investigated as well.It was found that the STA monolayer showed decreased friction,while the adhesive force was greatly decreased by increasing the surface roughness of the Al wafer to reduce the contact area between the atomic force microscope(AFM)tip and the sample surface to be tested.Thus the friction and adhesion of the Al wafer was effectively decreased by generating the STA monolayer, which indicated that it could be feasible and rational to prepare a surface with good adhesion resistance and lubricity by properly controlling the surface morphology and the chemical composition.Both the adhesion and friction decreased as the relative humidity was lowered from 65% to 10%,though the decrease extent became insignificant for the STA monolayer.展开更多
AIM: In patients with liver cirrhosis, hypoalbuminemia causes edema and ascites, and a reduction in the quality of life. Since musculature is catabolized to supply amino acids for albumin synthesis in malnutritional c...AIM: In patients with liver cirrhosis, hypoalbuminemia causes edema and ascites, and a reduction in the quality of life. Since musculature is catabolized to supply amino acids for albumin synthesis in malnutritional cirrhotic patients, muscular volume is hypothesized to play an important role in albumin production. Therefore, we investigated the correlation between serum albumin levels and the fat-free mass (FFM) in cirrhotic patients.METHODS: Fifty-seven patients (26 males and 31 females)with compensated liver cirrhosis were evaluated. Patients with edema or ascites were excluded from the study.Healthy volunteers (n = 104; 48 males and 56 females)were also evaluated as controls. FFM was measured using 5-500 kHz multifrequency bioelectric impedance analysis.To minimize the difference in FFM distribution between males and females, we introduced a new marker, relative FFM (rFFM), which represents the ratio of FFM in a patient relative to that in a volunteer of the same height. Following FFM measurement, the serum albumin levels of patients were assayed monthly.RESULTS: In patients with active cirrhosis (alanine aminotransaminase [ALT] ＞50 U/L), both albumin (the difference between maximum and minimum levels) and the standard deviation of albumin levels (SD-albumin) during the observation period showed a significant correlation with rFFM. Multiple linear regression analysis using variables such as rFFM, platelet number, and serum cholesterol levels,choline esterase, albumin, bilirubin, and ALT revealed that rFFM and ALT were significant and independent factors that influenced albumin or SD-albumin in cirrhotic patients.CONCLUSION: Our results indicate that cirrhotic patients with high rFFM showed less of a decrease in albumin levels, and that the muscle volume is one of the most important factors for maintaining serum albumins level in active cirrhosis. Exercise and protein-rich nutrition at the early stage of liver cirrhosis may be advisable for maintaining or increasing muscular volume.展开更多
Objective To compare the changes in body composition, including fat mass index （FMI） and fat free mass index （FFMI） during puberty development of obese and normal-weight children in China, and to explore the effec...Objective To compare the changes in body composition, including fat mass index （FMI） and fat free mass index （FFMI） during puberty development of obese and normal-weight children in China, and to explore the effect of age and gender on body composition. Methods A total of 356 children at the age of 7-15 years were enrolled in this study. Body composition of 10 normal-weight and obese children in each age group was measured by dual-energy x-ray absorptiometry （DEXA）. FFMI and FMI were calculated according to the following formula： FFMI （kg·m^-2）=FFM（kg）/ height^2（m^2） and FMI（kg·m^-2）=FM （kg）/ height^2（m^2）. Results The fat mass and fat free mass of obese children were significantly higher than those of normal-weight children （P〈0.05）. The FMI and FFMI of obese children increased significantly with age and were higher than those of the same sex, gender, and age normal-weight children （P〈0.05）. Conclusion The levels of fat mass, fat free mass, FMI, and FFMI are different in obese and normal-weight children, and gender effects are significant in boys having higher levels of these indicators than in girls. FFMI and FMI can be used as monitoring indexes in weight control of obese children.展开更多
An initial investigation on the roughness and frictional properties of the self-assembled thin films from polyelectrolytes is presented. Star-shaped C-60-Poly(styrene-maleic anhydride) was successful prepared. The mul...An initial investigation on the roughness and frictional properties of the self-assembled thin films from polyelectrolytes is presented. Star-shaped C-60-Poly(styrene-maleic anhydride) was successful prepared. The multilayer thin films have been fabricated on mica with diazoresin as the cationic polyelectrolyte and hydrolyzed star-shaped C-60-poly(styrene-maleic anhydride) as the anionic polyelectrolyte via self-assembly technique. The crosslinking structure of the films is formed from the conversion of ionic bond to covalent bond after UV irradiation. AFM/FFM investigations provide insights into the roughness and frictional properties on a microscale. The roughness depends strongly on the number of film layers in the case of C-60-containing films. The frictional forces of the films exhibited a well behaved non-linear relationship in response to the change of applied load. It supports the prediction of enhanced load-bearing property Of C60-containing thin films.展开更多
This paper presents two numerical realization of Preisach model by Density Function Method (DFM) and F Function Method (FFM) for a giant magnetostrictive actuator (GMA). Experiment and simulation showed that FFM is be...This paper presents two numerical realization of Preisach model by Density Function Method (DFM) and F Function Method (FFM) for a giant magnetostrictive actuator (GMA). Experiment and simulation showed that FFM is better than DFM for predicting precision of hysteresis loops. Lagrange bilinear interpolation algorithm is used in Preisach numerical realization to enhance prediction performance. A set of hysteresis loops and higher order reversal curves are predicted and experimentally verified. The good agreement between the measured and predicted curves shows that the classical Preisach model is effective for modelling the quasi-static hysteresis of the GMA.展开更多
文摘针对小流域暴雨洪水预报难的问题,利用模块化小流域暴雨洪水预报FFMS(Flash Flood Modul Simulation System)模型和HEC-HMS(Hydrologic Engineering Center Hydrological Model System)模型,以河南栾川、韩城及辽宁郝家店、梨庇峪4个山丘区小流域为例,对比分析了4个流域的暴雨洪水预报过程,以洪峰相对误差、峰现时间误差以及纳什系数等为评价准则,比较和分析了2个模型的预报精度和适用性。实例验证结果表明:虽然2种模型均能实现小流域暴雨洪水的预报,但从3个评价准则的结果来看,FFMS模型的预报精度优于HEC-HMS模型。研究成果证明了FFMS模型在山丘区小流域暴雨洪水预报中的有效性和可行性,可以在类似山丘区小流域暴雨洪水预报中进行推广应用。
基金The project supported by the National Natural Science Foundation of China (50375151,50323007,10225209)the Chinese Academy of Sciences (KJCX-SW-L2)
文摘A novel super-hydrophobic stearic acid(STA)film with a water contact angle of 166° was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine(PEI)film. The micro-tribological behavior of the super-hydrophobic STA monolayer was compared with that of the polished and PEI-coated Al surfaces.The effect of relative humidity on the adhesion and friction was investigated as well.It was found that the STA monolayer showed decreased friction,while the adhesive force was greatly decreased by increasing the surface roughness of the Al wafer to reduce the contact area between the atomic force microscope(AFM)tip and the sample surface to be tested.Thus the friction and adhesion of the Al wafer was effectively decreased by generating the STA monolayer, which indicated that it could be feasible and rational to prepare a surface with good adhesion resistance and lubricity by properly controlling the surface morphology and the chemical composition.Both the adhesion and friction decreased as the relative humidity was lowered from 65% to 10%,though the decrease extent became insignificant for the STA monolayer.
文摘AIM: In patients with liver cirrhosis, hypoalbuminemia causes edema and ascites, and a reduction in the quality of life. Since musculature is catabolized to supply amino acids for albumin synthesis in malnutritional cirrhotic patients, muscular volume is hypothesized to play an important role in albumin production. Therefore, we investigated the correlation between serum albumin levels and the fat-free mass (FFM) in cirrhotic patients.METHODS: Fifty-seven patients (26 males and 31 females)with compensated liver cirrhosis were evaluated. Patients with edema or ascites were excluded from the study.Healthy volunteers (n = 104; 48 males and 56 females)were also evaluated as controls. FFM was measured using 5-500 kHz multifrequency bioelectric impedance analysis.To minimize the difference in FFM distribution between males and females, we introduced a new marker, relative FFM (rFFM), which represents the ratio of FFM in a patient relative to that in a volunteer of the same height. Following FFM measurement, the serum albumin levels of patients were assayed monthly.RESULTS: In patients with active cirrhosis (alanine aminotransaminase [ALT] ＞50 U/L), both albumin (the difference between maximum and minimum levels) and the standard deviation of albumin levels (SD-albumin) during the observation period showed a significant correlation with rFFM. Multiple linear regression analysis using variables such as rFFM, platelet number, and serum cholesterol levels,choline esterase, albumin, bilirubin, and ALT revealed that rFFM and ALT were significant and independent factors that influenced albumin or SD-albumin in cirrhotic patients.CONCLUSION: Our results indicate that cirrhotic patients with high rFFM showed less of a decrease in albumin levels, and that the muscle volume is one of the most important factors for maintaining serum albumins level in active cirrhosis. Exercise and protein-rich nutrition at the early stage of liver cirrhosis may be advisable for maintaining or increasing muscular volume.
基金supported by the 973 Project "Mechanism of Type 2 Diabetes Progression" (No. 2006CB503900) from Ministry of Science and Technology of ChinaScientific Program from General Administration of Sport of China (No. 06134)
文摘Objective To compare the changes in body composition, including fat mass index （FMI） and fat free mass index （FFMI） during puberty development of obese and normal-weight children in China, and to explore the effect of age and gender on body composition. Methods A total of 356 children at the age of 7-15 years were enrolled in this study. Body composition of 10 normal-weight and obese children in each age group was measured by dual-energy x-ray absorptiometry （DEXA）. FFMI and FMI were calculated according to the following formula： FFMI （kg·m^-2）=FFM（kg）/ height^2（m^2） and FMI（kg·m^-2）=FM （kg）/ height^2（m^2）. Results The fat mass and fat free mass of obese children were significantly higher than those of normal-weight children （P〈0.05）. The FMI and FFMI of obese children increased significantly with age and were higher than those of the same sex, gender, and age normal-weight children （P〈0.05）. Conclusion The levels of fat mass, fat free mass, FMI, and FFMI are different in obese and normal-weight children, and gender effects are significant in boys having higher levels of these indicators than in girls. FFMI and FMI can be used as monitoring indexes in weight control of obese children.
基金This project is financially supported by the National Natural Science Foundation of China (No. 59843008).
文摘An initial investigation on the roughness and frictional properties of the self-assembled thin films from polyelectrolytes is presented. Star-shaped C-60-Poly(styrene-maleic anhydride) was successful prepared. The multilayer thin films have been fabricated on mica with diazoresin as the cationic polyelectrolyte and hydrolyzed star-shaped C-60-poly(styrene-maleic anhydride) as the anionic polyelectrolyte via self-assembly technique. The crosslinking structure of the films is formed from the conversion of ionic bond to covalent bond after UV irradiation. AFM/FFM investigations provide insights into the roughness and frictional properties on a microscale. The roughness depends strongly on the number of film layers in the case of C-60-containing films. The frictional forces of the films exhibited a well behaved non-linear relationship in response to the change of applied load. It supports the prediction of enhanced load-bearing property Of C60-containing thin films.
基金Project supported by the National Natural Science Foundation of China (No. 50105019)China Postdoctoral Science Foundation (No. 20060390337)
文摘This paper presents two numerical realization of Preisach model by Density Function Method (DFM) and F Function Method (FFM) for a giant magnetostrictive actuator (GMA). Experiment and simulation showed that FFM is better than DFM for predicting precision of hysteresis loops. Lagrange bilinear interpolation algorithm is used in Preisach numerical realization to enhance prediction performance. A set of hysteresis loops and higher order reversal curves are predicted and experimentally verified. The good agreement between the measured and predicted curves shows that the classical Preisach model is effective for modelling the quasi-static hysteresis of the GMA.
