When expansive soils in the original location are artificially transferred to landfill in different seasons,and subject to engineering activities afterwards,the corresponding deformation and stability of retaining str...When expansive soils in the original location are artificially transferred to landfill in different seasons,and subject to engineering activities afterwards,the corresponding deformation and stability of retaining structures become unpredictable.This necessitates the determination of lateral pressure coefficient at rest(k_(0) value)for expansive soils in landfill.Considering compaction,excavation of expansive soils,as well as construction of landfill in different seasons,series of stepwise loading and unloading consolidation tests at various moisture contents were carried out in this work to explore the evolution characteristics of k_(0) value and assess the dependence of k_(0) value on vertical stress and moisture content.Besides,scanning electron microscope(SEM)was used to track the change in microstructural features with vertical stresses.The results indicated that the k_(0) value of expansive soil shows a pronounced nonlinearity and is inextricably linked with vertical stress and moisture content,based on which a prediction formula to estimate the variation in k_(0) value with vertical stress during loading stage was proposed;there is a significant exponential increase in k_(0) value with overconsolidation ratio(OCR)during unloading stage,and OCR dominates the release of horizontal stress of expansive soil;SEM results revealed that with an increase in vertical stress,the anisotropy of expansive soil microstructure increases dramatically,causing a significant directional readjustment,which is macroscopically manifested as an initially rapid increase in k_(0) value;but when vertical stress increases to a critical value,the anisotropy of microstructure increases marginally,indicating a stable orientation occurring in the soil microstructure,which causes the k_(0) value to maintain a relatively stable value.展开更多
The effect of triethyl citrate(TEC)on the stability of cream preparations containing urea or hydroxyethyl urea along with their moisturizing effect on skin was investigated.The results showed that creams incorporating...The effect of triethyl citrate(TEC)on the stability of cream preparations containing urea or hydroxyethyl urea along with their moisturizing effect on skin was investigated.The results showed that creams incorporating urea or hydroxyethyl urea led to increase in pH value after a long-term and high-temperature storage.pH change in the latter one was relatively smaller.With the addition of TEC,the elevated pH of the formula system was suppressed.In the situation of stable formula,the higher the TEC added,the more significant inhibition effect on the pH change was observed.In the moisture retention test in vivo,compared to 27.19%moisture rate in negative control,cream preparations containing 5%urea or 5%hydroxyethyl urea had remarkable moisturizing effect,which were all higher than 52%.The latter one was relatively more prominent.There is no significant effect on moisturizing effect for product with TEC additive.展开更多
The relationship between moisture loss and oil uptake at different combination of Frying Oil Temperatures (FOT) and time during deep-fat frying of chicken meat was investigated in this study. Chicken meat samples were...The relationship between moisture loss and oil uptake at different combination of Frying Oil Temperatures (FOT) and time during deep-fat frying of chicken meat was investigated in this study. Chicken meat samples were diced and fried at different FOT (170°C, 180°C, and 190°C) in an industrial fryer for periods varying from 5 to 900 s. Fat analysis was accomplished in a soxhlet extraction apparatus with petroleum ether solvent. Prior to fat analysis samples were freeze dried and the moisture analysis was based on the standard AOAC standard method. The results show that a cook value of 415 s was found to give the most ideal sensory characteristics. The relationship between moisture loss and oil uptake during the initial phase of frying (°C and 190°C, respectively, and the rate (1.35 g/s) at FOT 170°C was significantly (P < 0.05) lower.展开更多
使用黄土高原气象台站的土壤湿度和降水观测资料以及GLDAS和CMFD再分析资料,分析黄土高原地区土壤湿度与降水量的时空分布及变化特征,通过回归分析、格兰杰因果检验和奇异值分解(Singular value decomposition,SVD),研究土壤湿度与降水...使用黄土高原气象台站的土壤湿度和降水观测资料以及GLDAS和CMFD再分析资料,分析黄土高原地区土壤湿度与降水量的时空分布及变化特征,通过回归分析、格兰杰因果检验和奇异值分解(Singular value decomposition,SVD),研究土壤湿度与降水之间的关系,分析初始土壤湿度影响随后降水的时间尺度与空间范围。结果显示:黄土高原的土壤湿度与随后1~2个月降水回归分析的解释方差相对较高,较大值在夏秋季节(7-10月),黄土高原不同区域(Ⅰ区、Ⅱ区和Ⅲ区)的土壤湿度与随后21天降水相关的时间较全区域的多,时间较集中,说明黄土高原土壤湿度分布不均匀,不同区域差别较大,较大的滞后降水时间尺度适用于较大空间范围的分析。格兰杰因果检验表明黄土高原全区域秋季(10月、11月)的初始土壤湿度对随后1个月或2个月的降水有显著影响,在Ⅲ区8月土壤湿度对10月的降水也有显著影响,这与回归分析的结果一致。再分析资料的SVD分解的结果显示,1979-2014年7月黄土高原中部、北部和东部土壤较湿润时,8月西部和北部边缘的降水偏多;9月东部的土壤偏湿润,则10月黄土高原西部以及南北部的一些地区降水偏多。土壤湿度与降水的显著相关区域重叠部分较少,说明黄土高原土壤湿度对降水的影响存在一定程度的时空不对称性。展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1509901)。
文摘When expansive soils in the original location are artificially transferred to landfill in different seasons,and subject to engineering activities afterwards,the corresponding deformation and stability of retaining structures become unpredictable.This necessitates the determination of lateral pressure coefficient at rest(k_(0) value)for expansive soils in landfill.Considering compaction,excavation of expansive soils,as well as construction of landfill in different seasons,series of stepwise loading and unloading consolidation tests at various moisture contents were carried out in this work to explore the evolution characteristics of k_(0) value and assess the dependence of k_(0) value on vertical stress and moisture content.Besides,scanning electron microscope(SEM)was used to track the change in microstructural features with vertical stresses.The results indicated that the k_(0) value of expansive soil shows a pronounced nonlinearity and is inextricably linked with vertical stress and moisture content,based on which a prediction formula to estimate the variation in k_(0) value with vertical stress during loading stage was proposed;there is a significant exponential increase in k_(0) value with overconsolidation ratio(OCR)during unloading stage,and OCR dominates the release of horizontal stress of expansive soil;SEM results revealed that with an increase in vertical stress,the anisotropy of expansive soil microstructure increases dramatically,causing a significant directional readjustment,which is macroscopically manifested as an initially rapid increase in k_(0) value;but when vertical stress increases to a critical value,the anisotropy of microstructure increases marginally,indicating a stable orientation occurring in the soil microstructure,which causes the k_(0) value to maintain a relatively stable value.
文摘The effect of triethyl citrate(TEC)on the stability of cream preparations containing urea or hydroxyethyl urea along with their moisturizing effect on skin was investigated.The results showed that creams incorporating urea or hydroxyethyl urea led to increase in pH value after a long-term and high-temperature storage.pH change in the latter one was relatively smaller.With the addition of TEC,the elevated pH of the formula system was suppressed.In the situation of stable formula,the higher the TEC added,the more significant inhibition effect on the pH change was observed.In the moisture retention test in vivo,compared to 27.19%moisture rate in negative control,cream preparations containing 5%urea or 5%hydroxyethyl urea had remarkable moisturizing effect,which were all higher than 52%.The latter one was relatively more prominent.There is no significant effect on moisturizing effect for product with TEC additive.
文摘The relationship between moisture loss and oil uptake at different combination of Frying Oil Temperatures (FOT) and time during deep-fat frying of chicken meat was investigated in this study. Chicken meat samples were diced and fried at different FOT (170°C, 180°C, and 190°C) in an industrial fryer for periods varying from 5 to 900 s. Fat analysis was accomplished in a soxhlet extraction apparatus with petroleum ether solvent. Prior to fat analysis samples were freeze dried and the moisture analysis was based on the standard AOAC standard method. The results show that a cook value of 415 s was found to give the most ideal sensory characteristics. The relationship between moisture loss and oil uptake during the initial phase of frying (°C and 190°C, respectively, and the rate (1.35 g/s) at FOT 170°C was significantly (P < 0.05) lower.
文摘使用黄土高原气象台站的土壤湿度和降水观测资料以及GLDAS和CMFD再分析资料,分析黄土高原地区土壤湿度与降水量的时空分布及变化特征,通过回归分析、格兰杰因果检验和奇异值分解(Singular value decomposition,SVD),研究土壤湿度与降水之间的关系,分析初始土壤湿度影响随后降水的时间尺度与空间范围。结果显示:黄土高原的土壤湿度与随后1~2个月降水回归分析的解释方差相对较高,较大值在夏秋季节(7-10月),黄土高原不同区域(Ⅰ区、Ⅱ区和Ⅲ区)的土壤湿度与随后21天降水相关的时间较全区域的多,时间较集中,说明黄土高原土壤湿度分布不均匀,不同区域差别较大,较大的滞后降水时间尺度适用于较大空间范围的分析。格兰杰因果检验表明黄土高原全区域秋季(10月、11月)的初始土壤湿度对随后1个月或2个月的降水有显著影响,在Ⅲ区8月土壤湿度对10月的降水也有显著影响,这与回归分析的结果一致。再分析资料的SVD分解的结果显示,1979-2014年7月黄土高原中部、北部和东部土壤较湿润时,8月西部和北部边缘的降水偏多;9月东部的土壤偏湿润,则10月黄土高原西部以及南北部的一些地区降水偏多。土壤湿度与降水的显著相关区域重叠部分较少,说明黄土高原土壤湿度对降水的影响存在一定程度的时空不对称性。
