The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and...The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and the internal component of a landslide.Therefore,considering the strength changes of the sliding zone with seepage effects,they correspond with the actual hydrogeological circumstances.To investigate the shear behavior of sliding zone soil under various seepage pressures,24 samples were conducted by a self-developed apparatus to observe the shear strength and measure the permeability coefficients at different deformation stages.After seepage-shear tests,the composition of clay minerals and microscopic structure on the shear surface were analyzed through X-ray and scanning electron microscope(SEM)to understand the coupling effects of seepage on strength.The results revealed that the sliding zone soil exhibited strain-hardening without seepage pressure.However,the introduction of seepage caused a significant reduction in shear strength,resulting in strain-softening characterized by a three-stage process.Long-term seepage action softened clay particles and transported broken particles into effective seepage channels,causing continuous damage to the interior structure and reducing the permeability coefficient.Increased seepage pressure decreased the peak strength by disrupting occlusal and frictional forces between sliding zone soil particles,which carried away more clay particles,contributing to an overhead structure in the soil that raised the permeability coefficient and decreased residual strength.The internal friction angle was less sensitive to variations in seepage pressure than cohesion.展开更多
To assess the work interruption information and examine the correlation between childbirth and the off-farm employment interruption of rural women,this article collected 3 820 women's childbirth and employment inf...To assess the work interruption information and examine the correlation between childbirth and the off-farm employment interruption of rural women,this article collected 3 820 women's childbirth and employment information over the past 18 years( 1998-2015),using multivariate regression to explore the impact of female individual,family and employment characteristics on probability of employment interruption and duration of interruption. Results indicated that overall,40% of women got interrupted after childbirth in rural areas and the average duration of interruption was about four years. Human capital factors,such as their work experience,first childbirth age and education experience,influence the probability of employment interruption,but these factors do not extend the duration of interruption for women who got interrupted.It is concluded that increasing the human capital of rural women is helpful to increasing their labor force participation rate after childbirth.展开更多
Summary of main observation and conclusion Electrophilic trifluoromethylthiolation has emerged as an important and efficient methodology for installing the SCF3 moiety onto an array of organic molecules.Due to the low...Summary of main observation and conclusion Electrophilic trifluoromethylthiolation has emerged as an important and efficient methodology for installing the SCF3 moiety onto an array of organic molecules.Due to the low reactivities of trifluoromethylthiolating reagents,these transformations often require activation through an exogenous Lewis/Br0nsted acid.We report herein the quantification of the activation capabilities of Lewis/Br0nsted acids for trifluoromethylthiolating reagents through computing the differenee in trifluoromethylthio cation donor ability(Tt+DA)between the"activated"and"unactivated"reagent.A moderate correlation is found to exist between the activation capability and Lewis acidity.展开更多
基金supported by the Major Program of the National Natural Science Foundation of China (Grant No.42090055)the National Major Scientific Instruments and Equipment Development Projects of China (Grant No.41827808)the National Nature Science Foundation of China (Grant No.42207216).
文摘The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and the internal component of a landslide.Therefore,considering the strength changes of the sliding zone with seepage effects,they correspond with the actual hydrogeological circumstances.To investigate the shear behavior of sliding zone soil under various seepage pressures,24 samples were conducted by a self-developed apparatus to observe the shear strength and measure the permeability coefficients at different deformation stages.After seepage-shear tests,the composition of clay minerals and microscopic structure on the shear surface were analyzed through X-ray and scanning electron microscope(SEM)to understand the coupling effects of seepage on strength.The results revealed that the sliding zone soil exhibited strain-hardening without seepage pressure.However,the introduction of seepage caused a significant reduction in shear strength,resulting in strain-softening characterized by a three-stage process.Long-term seepage action softened clay particles and transported broken particles into effective seepage channels,causing continuous damage to the interior structure and reducing the permeability coefficient.Increased seepage pressure decreased the peak strength by disrupting occlusal and frictional forces between sliding zone soil particles,which carried away more clay particles,contributing to an overhead structure in the soil that raised the permeability coefficient and decreased residual strength.The internal friction angle was less sensitive to variations in seepage pressure than cohesion.
文摘To assess the work interruption information and examine the correlation between childbirth and the off-farm employment interruption of rural women,this article collected 3 820 women's childbirth and employment information over the past 18 years( 1998-2015),using multivariate regression to explore the impact of female individual,family and employment characteristics on probability of employment interruption and duration of interruption. Results indicated that overall,40% of women got interrupted after childbirth in rural areas and the average duration of interruption was about four years. Human capital factors,such as their work experience,first childbirth age and education experience,influence the probability of employment interruption,but these factors do not extend the duration of interruption for women who got interrupted.It is concluded that increasing the human capital of rural women is helpful to increasing their labor force participation rate after childbirth.
基金the National Natural Science Foundation of China(Grant Nos.21772098 and 21933004)the Fun dame ntal Research Funds for the Central Un iversities.
文摘Summary of main observation and conclusion Electrophilic trifluoromethylthiolation has emerged as an important and efficient methodology for installing the SCF3 moiety onto an array of organic molecules.Due to the low reactivities of trifluoromethylthiolating reagents,these transformations often require activation through an exogenous Lewis/Br0nsted acid.We report herein the quantification of the activation capabilities of Lewis/Br0nsted acids for trifluoromethylthiolating reagents through computing the differenee in trifluoromethylthio cation donor ability(Tt+DA)between the"activated"and"unactivated"reagent.A moderate correlation is found to exist between the activation capability and Lewis acidity.
