The performance of a soil-pile system can be significantly influenced by ground motion parameters. However, few research efforts have been performed to provide a complete description of the influence of key ground mot...The performance of a soil-pile system can be significantly influenced by ground motion parameters. However, few research efforts have been performed to provide a complete description of the influence of key ground motion parameters on the pile’s behavior in liquefiable soil. In this study, a three-dimensional finite element（FE） model, incorporating a multisurface plasticity solid-fluid fully coupled formulation soil constitutive model, is developed and calibrated based on centrifuge test data. Seventy-two near-fault non-pulse-like（NF-NP） and seventy-two near-fault pulse-like（NF-P） ground motion records are studied with the calibrated FE model to distinguish the effects of several common ground motion parameters soon afterwards. Base on the parametric study results, a simple index, RPGV/PGA（i.e., the ratio of peak ground velocity（PGV） to peak ground acceleration（PGA））, shows its capability on characterizing the pile behavior under both NF-NP and NF-P ground motions. Furthermore, two equations are developed to characterize the relationships between the RPGV/PGA as well as the maximum pile’s moments and displacements. In general, this study can be helpful to gain new insights on the influence of typical index parameters for near-field ground motions on the response of the pile foundation in liquefiable soil.展开更多
Objective This study aimed to measure the basal energy expenditure(BEE)of Chinese healthy adults and establish an accurate predictive equation for this population.Methods In total,470 Chinese healthy adults had their ...Objective This study aimed to measure the basal energy expenditure(BEE)of Chinese healthy adults and establish an accurate predictive equation for this population.Methods In total,470 Chinese healthy adults had their BEE measured using the Cosmed K4b2 portable metabolic system.Multiple linear regression analysis was applied to develop new optimal equations for predicting BEE.The bias,accuracy rate,concordance correlation coefficient(CCC),and root mean square error(RMSE)were used to evaluate the accuracy of the predictive equations.Results There was a significant difference in BEE between males and females,with 5,954 kJ/d and 5,089 kJ/d,respectively.People living in rural areas expended significantly higher BEE(5,885 kJ/d)than those in urban areas(5,279 kJ/d).Previous equations developed by Henry,Schofield,Harris-Benedict(HB),and Liu overestimated the BEE of Chinese healthy adults.The new equations derived from the present study displayed the smallest average bias and RMSE from the measured basal energy expenditure(mBEE).The CCC of the new equations was higher than other predictive equations,but it was lower than 0.8.There was no significant difference in the accuracy rate among all predictive equations.Conclusions Sex and regional differences in BEE were observed in Chinese healthy adults.Neither the widely used previous predictive equations nor the one derived in the present study were accurate enough for estimating the BEE of Chinese healthy adults.Further study is required to develop more accurate equations for predicting the BEE of Chinese healthy adults aged between 20–45 years.展开更多
To check the applicabilities of the simple density equation and viscosity equation in the semi-ideal solution theory to nonelectrolyte solutions, the densities and viscosities were measured for the quaternary system m...To check the applicabilities of the simple density equation and viscosity equation in the semi-ideal solution theory to nonelectrolyte solutions, the densities and viscosities were measured for the quaternary system mannitol-sorbitol-D-glucose-HzO and its ternary subsystems mannitol-D-glucose-H2O and sorbitol-D-glucose-H2O at 298.15K. The results were used to test the applicability of the simple equations for the density and viscosity of the multicomponent nonelectrolyte solution. The agreements between the predicted and measured results are good.展开更多
基金National Key R&D Program of China under Grant No.2016YFE0205100the National Natural Science Foundation of China under Grant No.51578195+1 种基金the Technology Research and Development Plan Program of China Railway Corporation under Grant No.J2016Z025the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences under Grant No.Z016007
文摘The performance of a soil-pile system can be significantly influenced by ground motion parameters. However, few research efforts have been performed to provide a complete description of the influence of key ground motion parameters on the pile’s behavior in liquefiable soil. In this study, a three-dimensional finite element（FE） model, incorporating a multisurface plasticity solid-fluid fully coupled formulation soil constitutive model, is developed and calibrated based on centrifuge test data. Seventy-two near-fault non-pulse-like（NF-NP） and seventy-two near-fault pulse-like（NF-P） ground motion records are studied with the calibrated FE model to distinguish the effects of several common ground motion parameters soon afterwards. Base on the parametric study results, a simple index, RPGV/PGA（i.e., the ratio of peak ground velocity（PGV） to peak ground acceleration（PGA））, shows its capability on characterizing the pile behavior under both NF-NP and NF-P ground motions. Furthermore, two equations are developed to characterize the relationships between the RPGV/PGA as well as the maximum pile’s moments and displacements. In general, this study can be helpful to gain new insights on the influence of typical index parameters for near-field ground motions on the response of the pile foundation in liquefiable soil.
基金Supported by Key Projects of the National Science and Technology Pillar Program[No.2008BAI58B01].
文摘Objective This study aimed to measure the basal energy expenditure(BEE)of Chinese healthy adults and establish an accurate predictive equation for this population.Methods In total,470 Chinese healthy adults had their BEE measured using the Cosmed K4b2 portable metabolic system.Multiple linear regression analysis was applied to develop new optimal equations for predicting BEE.The bias,accuracy rate,concordance correlation coefficient(CCC),and root mean square error(RMSE)were used to evaluate the accuracy of the predictive equations.Results There was a significant difference in BEE between males and females,with 5,954 kJ/d and 5,089 kJ/d,respectively.People living in rural areas expended significantly higher BEE(5,885 kJ/d)than those in urban areas(5,279 kJ/d).Previous equations developed by Henry,Schofield,Harris-Benedict(HB),and Liu overestimated the BEE of Chinese healthy adults.The new equations derived from the present study displayed the smallest average bias and RMSE from the measured basal energy expenditure(mBEE).The CCC of the new equations was higher than other predictive equations,but it was lower than 0.8.There was no significant difference in the accuracy rate among all predictive equations.Conclusions Sex and regional differences in BEE were observed in Chinese healthy adults.Neither the widely used previous predictive equations nor the one derived in the present study were accurate enough for estimating the BEE of Chinese healthy adults.Further study is required to develop more accurate equations for predicting the BEE of Chinese healthy adults aged between 20–45 years.
基金Supported by the National Natural Science Foundation of China （No.20276037）
文摘To check the applicabilities of the simple density equation and viscosity equation in the semi-ideal solution theory to nonelectrolyte solutions, the densities and viscosities were measured for the quaternary system mannitol-sorbitol-D-glucose-HzO and its ternary subsystems mannitol-D-glucose-H2O and sorbitol-D-glucose-H2O at 298.15K. The results were used to test the applicability of the simple equations for the density and viscosity of the multicomponent nonelectrolyte solution. The agreements between the predicted and measured results are good.
