In this paper, we have proposed the theory of gravity gauge, and the gravity theory has been introduced into quantum field theory. We have further given the tensor equation of gravity field in the flat space, and foun...In this paper, we have proposed the theory of gravity gauge, and the gravity theory has been introduced into quantum field theory. We have further given the tensor equation of gravity field in the flat space, and found the gravity field equation is the Lorentz covariant and gauge invariant. The gravity theory can be quantized and can be unified with the electroweak and strong interaction at a new gauge group .展开更多
We present a phosphonium-containing catalyst generated in situ from phosphine and tert-butyl acrylate that serves as an unusual Lewis base catalyst.It was applied for the promotion of a remote 1,6-cyanation reaction o...We present a phosphonium-containing catalyst generated in situ from phosphine and tert-butyl acrylate that serves as an unusual Lewis base catalyst.It was applied for the promotion of a remote 1,6-cyanation reaction of p-quinone methides and fuchsones employing trimethylsilyl cyanide as the cyanide source.A diverse range ofα-diaryl andα-triaryl acetonitriles was obtained in high yields under mild reaction conditions with low catalyst loading(5 mol%).The practicality and utility of this protocol were demonstrated via the gram-scale preparation and facile elaboration of products.Mechanistic investigations(in situ NMR and ESI-MS analysis)were employed to characterize the active zwitterionic phosphonium intermediate,which was the“true”active catalyst.展开更多
Health literacy is the main component of health quality and a comprehensive health indicator reflecting related idea,cognition,behavior and skills.In this paper,we investigated the overall level and characteristics of...Health literacy is the main component of health quality and a comprehensive health indicator reflecting related idea,cognition,behavior and skills.In this paper,we investigated the overall level and characteristics of health literacy based on the survey data of college students in Beijing.The differences of health literacy level among sub-groups were compared,and the influencing factors of health literacy were discussed.The results showed that college students had a higher level in overall health literacy than other peers,but a lower level in the prevention of chronic disease and infectious disease.The level of health literacy of college students was mainly affected by their major,hometown,and situation of health-related elective.Besides,we also found that the way college students used to acquire health knowledge was inconsistent with their expectations,and the requirements for health education were also very high.More systematic and comprehensive health education should be provided in universities,with an emphasis on the knowledge of lifestyle and daily habits.展开更多
文摘In this paper, we have proposed the theory of gravity gauge, and the gravity theory has been introduced into quantum field theory. We have further given the tensor equation of gravity field in the flat space, and found the gravity field equation is the Lorentz covariant and gauge invariant. The gravity theory can be quantized and can be unified with the electroweak and strong interaction at a new gauge group .
基金This work was supported by the National Natural Science Foundation of China(32030075),China Postdoctoral Science Foundation and the Special Research Assistant Grant Program of the Chinese Academy of Sciences.
基金support was provided by the National Natural Science Foundation of China(21971165,21921002,21772035,22101189)National Key R&D Program of China(2018YFA0903500)National Natural Science Foundation of Hunan(2021JJ40150).
文摘We present a phosphonium-containing catalyst generated in situ from phosphine and tert-butyl acrylate that serves as an unusual Lewis base catalyst.It was applied for the promotion of a remote 1,6-cyanation reaction of p-quinone methides and fuchsones employing trimethylsilyl cyanide as the cyanide source.A diverse range ofα-diaryl andα-triaryl acetonitriles was obtained in high yields under mild reaction conditions with low catalyst loading(5 mol%).The practicality and utility of this protocol were demonstrated via the gram-scale preparation and facile elaboration of products.Mechanistic investigations(in situ NMR and ESI-MS analysis)were employed to characterize the active zwitterionic phosphonium intermediate,which was the“true”active catalyst.
基金Supported by the Fundamental Research Funds for the Central Universities,and the Research Funds of Renmin University of China(18XNB009).
文摘Health literacy is the main component of health quality and a comprehensive health indicator reflecting related idea,cognition,behavior and skills.In this paper,we investigated the overall level and characteristics of health literacy based on the survey data of college students in Beijing.The differences of health literacy level among sub-groups were compared,and the influencing factors of health literacy were discussed.The results showed that college students had a higher level in overall health literacy than other peers,but a lower level in the prevention of chronic disease and infectious disease.The level of health literacy of college students was mainly affected by their major,hometown,and situation of health-related elective.Besides,we also found that the way college students used to acquire health knowledge was inconsistent with their expectations,and the requirements for health education were also very high.More systematic and comprehensive health education should be provided in universities,with an emphasis on the knowledge of lifestyle and daily habits.
