As the world’s largest developing country,the ability of China’s agricultural resource utilization to effectively support the current and future food security goals has been affected by a variety of factors(e.g.,tra...As the world’s largest developing country,the ability of China’s agricultural resource utilization to effectively support the current and future food security goals has been affected by a variety of factors(e.g.,transformed supply channels,tightening international situation and frequent emergencies)in recent years and has attracted extensive attention from the academic community subject to multiple factors.This study uses literature review,statistical analysis,and spatial analysis methods to systematically explore China’s food security situation in the context of farmland resource constraints.It is found that the demand-side pressures such as demographic changes,social class differentiation,and dietary structure adjustments derived from economic growth and rapid urbanization have placed extremely high expectations on food supply.However,the quantitative restrictions,utilization ways,and health risks of farmland resources on the supply side constitute a huge hidden concern that affects the stability of food production.Although China’s farmland protection system is undergoing a transition from focusing on quantity management to sustainable use,the matching and coordinating demand pressure and supply capacity for food security is unbalanced.Therefore,facing uncertain future development scenarios,policymakers should focus on building a resilient space for China’s farmland protection to withstand the interference of major emergencies.The existing farmland protection space policy can be integrated by establishing a national farmland strategic reserve system(based on resilient space),and further development of targeted use control measures for zoning,grading,and classification will help realize sustainable China’s farmland resources use.展开更多
The design of a total energy conserving semi-implicit scheme for the multiple-level baroclinic primitive equation has remained an unsolved problem for a long time. In this work, however, we follow an energy perfect co...The design of a total energy conserving semi-implicit scheme for the multiple-level baroclinic primitive equation has remained an unsolved problem for a long time. In this work, however, we follow an energy perfect conserving semi-implicit scheme of a European Centre for Medium-Range Weather Forecasts (ECMWF) type sigma-coordinate primitive equation which has recently successfully formulated. Some real-data contrast tests between the model of the new conserving scheme and that of the ECMWF-type of global spectral semi-implicit scheme show that the RMS error of the averaged forecast Height at 850 hPa can be clearly improved after the first integral week. The reduction also reaches 50 percent by the 30th day. Further contrast tests demonstrate that the RMS error of the monthly mean height in the middle and lower troposphere also be largely reduced, and some well-known systematical defects can be greatly improved. More detailed analysis reveals that part of the positive contributions comes from improvements of the extra-long wave components. This indicates that a remarkable improvement of the model climate drift level can be achieved by the actual realizing of a conserving time-difference scheme, which thereby eliminates a corresponding computational systematic error source/sink found in the currently-used traditional type of weather and climate system models in relation to the baroclinic primitive equations.展开更多
Intervention based on“digital therapeutics”(DTs)to aid smoking cessation(SC)has developed in recent years.This systematic review and meta-analysis aimed to explore the efficacy of DTs in SC.Databases(PubMed,Embase,S...Intervention based on“digital therapeutics”(DTs)to aid smoking cessation(SC)has developed in recent years.This systematic review and meta-analysis aimed to explore the efficacy of DTs in SC.Databases(PubMed,Embase,Scopus,Institute of Electrical and Electronics Engineers Xplore,ClinicalTrials,Science Direct,Web of Science,China National Knowledge Infrastructure,Chinese Science and Technology Periodical Database,Wanfang,Cochrane Central Register of Controlled Trials)from inception to June 27,2022 were searched to collect randomized controlled trials focusing on use of DTs for SC.Revman 5.3 and Stata16 were used for meta-analysis.After literature screening,data extraction,and quality assessment by two researchers.33 studies(19,749 participants)were included.Compared with the control group,DTs significantly increased the prevalence of abstinence of smokers[OR=1.77,95%CI[1.39,2.26],p=0],significantly increased the point prevalence abstinence(PPA)[OR=1.45,95%CI[1.18,1.78],p=0],and improved participation in SC programs[OR=1.12,95%CI[1.01,1.24],p=0.038].Subgroup analysis showed that,among different intervention groups,the prevalence of DTs-assisted SC in chronic obstructive pulmonary disease(COPD)smokers was higher than that in other groups[OR=5.18,95%CI[1.49,18.05],p=0.001],the prevalence of WeChat-assisted SC in smokers was higher than that in other groups[OR=4.37,95%CI[2.21,8.67],p=0].This meta-analysis showed that DTs-assisted SC improved the prevalence of abstinence,PPA,and increased the participation of smokers in SC programs.展开更多
China now faces double challenges of water resources shortage and severe water pollution. To resolve Chinese water pollution problems and reduce its impacts on human health, economic growth and social develop- ment, t...China now faces double challenges of water resources shortage and severe water pollution. To resolve Chinese water pollution problems and reduce its impacts on human health, economic growth and social develop- ment, the situation of wastewater treatment was investi- gated. Excess sludge and greenhouse gases （GHGs） emitted during wastewater treatment were also surveyed. It is concluded that Chinese water pollution problems should be systematically resolved with inclusion of wastewater and the solid waste and GHGs generated during wastewater treatment. Strategies proposed for the wastewater treatment in China herein were also adequate for other countries, especially for the developing countries with similar economic conditions to China.展开更多
Modern science has solved the systematic dynamic problems involving complexity such as complex systems by logical solution algebraically such as the old chaos theory derived from algebraic statistics based on determin...Modern science has solved the systematic dynamic problems involving complexity such as complex systems by logical solution algebraically such as the old chaos theory derived from algebraic statistics based on determinism. It is very vague and difficult for us. Moreover, modern science treats systems dynamic problems as logical static problems according to determinism. However, this study proposes a novel solution for systematic problems, it is accomplished by systems analysis theory based on a third science (indeterminism) as it is more precise and easier to understand compared to chaos theory. Furthermore, it is suitable for non-physicists, because it is supported by computer simulations without any mathematical processing. Thus, it can be solved especially regressive systems solution. Therefore, this provided an innovative scientific result to non-physicists for their unsolved systematic problems in modern science.展开更多
A design of super-orthogonal space-time trellis codes （SOSTTCs） based on the trace criterion （TC） is proposed for improving the design of SOSTTCs. The shortcomings of the rank and determinant criteria based design...A design of super-orthogonal space-time trellis codes （SOSTTCs） based on the trace criterion （TC） is proposed for improving the design of SOSTTCs. The shortcomings of the rank and determinant criteria based design and the advantages of the TC-based design are analyzed. The optimization principle of four factors is presented, which includes the space-time block coding （STBC） scheme, set partitioning, trellis structure, and the assignment of signal subsets and STBC schemes in the trellis. According to this principle, systematical and handcrafted design steps are given in detail. By constellation expansion, the code performance can be further improved. The code design results are given, and the new codes outperform others in the simulation.展开更多
The stability of ore pillar in mine is essential for the safe and efficient mining.Based on the energy evolvement rule in ore pillar and roadway roof system,the roadway roof and ore pillar are treated as energy releas...The stability of ore pillar in mine is essential for the safe and efficient mining.Based on the energy evolvement rule in ore pillar and roadway roof system,the roadway roof and ore pillar are treated as energy release body and energy dissipation body,respectively.Therefore,the double-block mechanical model is established with energy dissipation body and energy release body,and the energy mechanism of ore pillar instability is obtained,based on the fold catastrophe mathematical theory.The research result indicates that the dynamic instability of ore pillar is a physical instability problem caused by the strain softening property of ore mass,and the instability type of ore pillar is determined by the stiffness parameter of double-block mechanical system.When the systematical stiffness parameter is greater than or equal to 1,the equilibrium position of double-block mechanical system passes through shaft K-1 or the origin,from branch 1 of unstable equilibrium state to branch 2 of stable equilibrium state by smooth transition,and the ore pillar shows quasi-static fracture.When the systematical stiffness parameter is less than 1,the equilibrium position of double-block system mutates from branch 1 of unstable equilibrium state to branch 2 of stable equilibrium state by jumping transition,and the ore pillar shows dynamic instability.The research result could provide theoretical guidance for the prevention measures of ore pillar instability.展开更多
基金National Social Science Fund of China,No.19ZDA096National Natural Science Foundation of China,No.41971234,No.41971235+1 种基金Postgraduate Research and Practice Innovation Project of Jiangsu Province,No.KYCX21_0039Open Fund of Key Laboratory of Coastal Zone Exploitation and Protection,Ministry of Natural Resources,No.2021CZEPK07。
文摘As the world’s largest developing country,the ability of China’s agricultural resource utilization to effectively support the current and future food security goals has been affected by a variety of factors(e.g.,transformed supply channels,tightening international situation and frequent emergencies)in recent years and has attracted extensive attention from the academic community subject to multiple factors.This study uses literature review,statistical analysis,and spatial analysis methods to systematically explore China’s food security situation in the context of farmland resource constraints.It is found that the demand-side pressures such as demographic changes,social class differentiation,and dietary structure adjustments derived from economic growth and rapid urbanization have placed extremely high expectations on food supply.However,the quantitative restrictions,utilization ways,and health risks of farmland resources on the supply side constitute a huge hidden concern that affects the stability of food production.Although China’s farmland protection system is undergoing a transition from focusing on quantity management to sustainable use,the matching and coordinating demand pressure and supply capacity for food security is unbalanced.Therefore,facing uncertain future development scenarios,policymakers should focus on building a resilient space for China’s farmland protection to withstand the interference of major emergencies.The existing farmland protection space policy can be integrated by establishing a national farmland strategic reserve system(based on resilient space),and further development of targeted use control measures for zoning,grading,and classification will help realize sustainable China’s farmland resources use.
基金This research was jointly supported by the National Key Programme for Developing Basic Sciences (G1998040911) and the National Natural Science Foundation of China under Grant Nos. 49675267, 49205058, and 49975020.
文摘The design of a total energy conserving semi-implicit scheme for the multiple-level baroclinic primitive equation has remained an unsolved problem for a long time. In this work, however, we follow an energy perfect conserving semi-implicit scheme of a European Centre for Medium-Range Weather Forecasts (ECMWF) type sigma-coordinate primitive equation which has recently successfully formulated. Some real-data contrast tests between the model of the new conserving scheme and that of the ECMWF-type of global spectral semi-implicit scheme show that the RMS error of the averaged forecast Height at 850 hPa can be clearly improved after the first integral week. The reduction also reaches 50 percent by the 30th day. Further contrast tests demonstrate that the RMS error of the monthly mean height in the middle and lower troposphere also be largely reduced, and some well-known systematical defects can be greatly improved. More detailed analysis reveals that part of the positive contributions comes from improvements of the extra-long wave components. This indicates that a remarkable improvement of the model climate drift level can be achieved by the actual realizing of a conserving time-difference scheme, which thereby eliminates a corresponding computational systematic error source/sink found in the currently-used traditional type of weather and climate system models in relation to the baroclinic primitive equations.
文摘Intervention based on“digital therapeutics”(DTs)to aid smoking cessation(SC)has developed in recent years.This systematic review and meta-analysis aimed to explore the efficacy of DTs in SC.Databases(PubMed,Embase,Scopus,Institute of Electrical and Electronics Engineers Xplore,ClinicalTrials,Science Direct,Web of Science,China National Knowledge Infrastructure,Chinese Science and Technology Periodical Database,Wanfang,Cochrane Central Register of Controlled Trials)from inception to June 27,2022 were searched to collect randomized controlled trials focusing on use of DTs for SC.Revman 5.3 and Stata16 were used for meta-analysis.After literature screening,data extraction,and quality assessment by two researchers.33 studies(19,749 participants)were included.Compared with the control group,DTs significantly increased the prevalence of abstinence of smokers[OR=1.77,95%CI[1.39,2.26],p=0],significantly increased the point prevalence abstinence(PPA)[OR=1.45,95%CI[1.18,1.78],p=0],and improved participation in SC programs[OR=1.12,95%CI[1.01,1.24],p=0.038].Subgroup analysis showed that,among different intervention groups,the prevalence of DTs-assisted SC in chronic obstructive pulmonary disease(COPD)smokers was higher than that in other groups[OR=5.18,95%CI[1.49,18.05],p=0.001],the prevalence of WeChat-assisted SC in smokers was higher than that in other groups[OR=4.37,95%CI[2.21,8.67],p=0].This meta-analysis showed that DTs-assisted SC improved the prevalence of abstinence,PPA,and increased the participation of smokers in SC programs.
文摘China now faces double challenges of water resources shortage and severe water pollution. To resolve Chinese water pollution problems and reduce its impacts on human health, economic growth and social develop- ment, the situation of wastewater treatment was investi- gated. Excess sludge and greenhouse gases （GHGs） emitted during wastewater treatment were also surveyed. It is concluded that Chinese water pollution problems should be systematically resolved with inclusion of wastewater and the solid waste and GHGs generated during wastewater treatment. Strategies proposed for the wastewater treatment in China herein were also adequate for other countries, especially for the developing countries with similar economic conditions to China.
文摘Modern science has solved the systematic dynamic problems involving complexity such as complex systems by logical solution algebraically such as the old chaos theory derived from algebraic statistics based on determinism. It is very vague and difficult for us. Moreover, modern science treats systems dynamic problems as logical static problems according to determinism. However, this study proposes a novel solution for systematic problems, it is accomplished by systems analysis theory based on a third science (indeterminism) as it is more precise and easier to understand compared to chaos theory. Furthermore, it is suitable for non-physicists, because it is supported by computer simulations without any mathematical processing. Thus, it can be solved especially regressive systems solution. Therefore, this provided an innovative scientific result to non-physicists for their unsolved systematic problems in modern science.
文摘A design of super-orthogonal space-time trellis codes （SOSTTCs） based on the trace criterion （TC） is proposed for improving the design of SOSTTCs. The shortcomings of the rank and determinant criteria based design and the advantages of the TC-based design are analyzed. The optimization principle of four factors is presented, which includes the space-time block coding （STBC） scheme, set partitioning, trellis structure, and the assignment of signal subsets and STBC schemes in the trellis. According to this principle, systematical and handcrafted design steps are given in detail. By constellation expansion, the code performance can be further improved. The code design results are given, and the new codes outperform others in the simulation.
基金This work was supported by the National Natural Science Foundation of China(51704095,51774110,51504081)the Research Fund of the State Key Laboratory of Coal Resources and Safe Mining(13KF02)+2 种基金the Research Fund of Henan Key Laboratory for Green and Efficient Mining and Comprehensive Utilization of Mineral Resources(S201619)the Foundation for Higher Education Key Research Project by Henan Province(18A440012,14A440001)the Ph.D.Programs Foundation of Henan Polytechnic University(B2014-50,B2016-67).
文摘The stability of ore pillar in mine is essential for the safe and efficient mining.Based on the energy evolvement rule in ore pillar and roadway roof system,the roadway roof and ore pillar are treated as energy release body and energy dissipation body,respectively.Therefore,the double-block mechanical model is established with energy dissipation body and energy release body,and the energy mechanism of ore pillar instability is obtained,based on the fold catastrophe mathematical theory.The research result indicates that the dynamic instability of ore pillar is a physical instability problem caused by the strain softening property of ore mass,and the instability type of ore pillar is determined by the stiffness parameter of double-block mechanical system.When the systematical stiffness parameter is greater than or equal to 1,the equilibrium position of double-block mechanical system passes through shaft K-1 or the origin,from branch 1 of unstable equilibrium state to branch 2 of stable equilibrium state by smooth transition,and the ore pillar shows quasi-static fracture.When the systematical stiffness parameter is less than 1,the equilibrium position of double-block system mutates from branch 1 of unstable equilibrium state to branch 2 of stable equilibrium state by jumping transition,and the ore pillar shows dynamic instability.The research result could provide theoretical guidance for the prevention measures of ore pillar instability.
