A population-based case-control study was conducted to evaluate the relative fac^tors in the environments, agricultural works, outdoor activities, and the effectiveness of Lyme borreliosis （LB）- associated personal ...A population-based case-control study was conducted to evaluate the relative fac^tors in the environments, agricultural works, outdoor activities, and the effectiveness of Lyme borreliosis （LB）- associated personal protective measure.c; in Beijing. Thirty-four cases and 272 controls were personally interviewed by well-trained interviewers. Venous blood samples were taken from eac：h subject. Sowing or harvesting in summer （OR=2.571, 95% CI： 1.109-5.962）, living in house with weeding in the yard （OR=2.247, 95% CI： 1.062-4.755）.展开更多
Foam is widely used in the petroleum industry thanks to its unique properties and performance. Its application to water control in oil wells has received more and more attention. The stability of nitrogen foam was inv...Foam is widely used in the petroleum industry thanks to its unique properties and performance. Its application to water control in oil wells has received more and more attention. The stability of nitrogen foam was investigated in pressurized equipment and sand pack. The result indicated that with increasing pressure （0-2 MPa） the stability of foam in the pressurized equipment increased linearly. Increased nitrogen injection pressure caused better dispersion of nitrogen-foaming solution in porous media. The initial residual resistance factor to gas was an exponential function of injection pressure, but the residual resistance factor （to gas and liquid） decreased exponentially with time. The halflife of foam in porous media （expressed in residual resistance factor） was much longer than that in bulk phase （expressed in foam height）. Pore model analysis indicated that good dispersion in porous media and the presence of thick liquid film during dispersion were the main reasons for high stability. Field test indicated that effective residence of foam in the formation not only resulted in much better heat insulation, but also improved steam stimulation by enhancing steam heating.展开更多
Based on census data from China,this paper uses SOCSIM microscopic simulation method to decompose the key factors of family transition into demographic and residence pattern factors.The former are further broken down ...Based on census data from China,this paper uses SOCSIM microscopic simulation method to decompose the key factors of family transition into demographic and residence pattern factors.The former are further broken down into demographic inertia,fertility,mortality and marriage rate.The results indicate that the current demographic changes are relatively small and,thus,the small fluctuations caused by demographic changes contribute much less than residence pattern to the family transition.Among the demographic factors,demographic inertia and fertility have a greater effect on family transition and the impacts caused by fertility and marriage rate are consistent with the direction of the overall influence of demographic factors:increasing the proportion of single-person households,one-generation households,and two-generation households,and decreasing the proportion of three-generation or more households.In contrast,the effect of mortality rate was opposite to that of fertility rate,which increased the proportion of populations living in single-person,one-generation,and two-generation households,but the decreased the proportion of the population living in three-generation or more households.展开更多
基金supported by National Key Program for Infectious Diseases of China(2012ZX10004215-003-001)Beijing Natural Science Foundation(Project No.7133234)
文摘A population-based case-control study was conducted to evaluate the relative fac^tors in the environments, agricultural works, outdoor activities, and the effectiveness of Lyme borreliosis （LB）- associated personal protective measure.c; in Beijing. Thirty-four cases and 272 controls were personally interviewed by well-trained interviewers. Venous blood samples were taken from eac：h subject. Sowing or harvesting in summer （OR=2.571, 95% CI： 1.109-5.962）, living in house with weeding in the yard （OR=2.247, 95% CI： 1.062-4.755）.
文摘Foam is widely used in the petroleum industry thanks to its unique properties and performance. Its application to water control in oil wells has received more and more attention. The stability of nitrogen foam was investigated in pressurized equipment and sand pack. The result indicated that with increasing pressure （0-2 MPa） the stability of foam in the pressurized equipment increased linearly. Increased nitrogen injection pressure caused better dispersion of nitrogen-foaming solution in porous media. The initial residual resistance factor to gas was an exponential function of injection pressure, but the residual resistance factor （to gas and liquid） decreased exponentially with time. The halflife of foam in porous media （expressed in residual resistance factor） was much longer than that in bulk phase （expressed in foam height）. Pore model analysis indicated that good dispersion in porous media and the presence of thick liquid film during dispersion were the main reasons for high stability. Field test indicated that effective residence of foam in the formation not only resulted in much better heat insulation, but also improved steam stimulation by enhancing steam heating.
文摘Based on census data from China,this paper uses SOCSIM microscopic simulation method to decompose the key factors of family transition into demographic and residence pattern factors.The former are further broken down into demographic inertia,fertility,mortality and marriage rate.The results indicate that the current demographic changes are relatively small and,thus,the small fluctuations caused by demographic changes contribute much less than residence pattern to the family transition.Among the demographic factors,demographic inertia and fertility have a greater effect on family transition and the impacts caused by fertility and marriage rate are consistent with the direction of the overall influence of demographic factors:increasing the proportion of single-person households,one-generation households,and two-generation households,and decreasing the proportion of three-generation or more households.In contrast,the effect of mortality rate was opposite to that of fertility rate,which increased the proportion of populations living in single-person,one-generation,and two-generation households,but the decreased the proportion of the population living in three-generation or more households.
