The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state discharge.The active control of inward particl...The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state discharge.The active control of inward particle transport is considered as one of the most critical issues of magnetic confinement fusion.Recently,it is realized preliminarily by adding a biased endplate in the Peking University Plasma Test(PPT)device.The results reveal that the inward particle flux increases with the bias voltage of the endplate.It is also found that the profile of radial electric field(Er)shear is flattened by the increased bias voltage.Radial velocity fluctuations affect the inward particle more than density fluctuations,and the frequency of the dominant mode driving inward particle flux increases with the biased voltage applied to the endplate.The experimental results in the PPT device provide a method to actively control the inward particle flux using a biased endplate and enrich the understanding of the relationship between E_(r)×B shear and turbulence transport.展开更多
The waves in a magnetic null could play important roles during 3D magnetic reconnection.Some preliminary clues in this paper show that the ion Bernstein wave(IBW)may be closely related to transport process in magnetic...The waves in a magnetic null could play important roles during 3D magnetic reconnection.Some preliminary clues in this paper show that the ion Bernstein wave(IBW)may be closely related to transport process in magnetic null region.The magnetic null configuration experiment reported here is set up in a linear helicon plasma device,Peking University plasma test device(PPT).The wave modes with frequencies between the first and third harmonics of local ion cyclotron frequency(w_(ci))are observed in the separatrix of magnetic null,which are identified as the IBW based on the dispersion relation.Further analysis shows that IBW could drive substantial particle flux across the magnetic separatrix.The theoretical radial particle flux driven by IBW and the measured parallel flow in PPT device are almost on the same order,which shows that IBW may play an important role during 3D reconnection process.展开更多
Background Prompt and appropriate clinical management of malaria is critical for reducing the continued high burden of malaria among children under five years in sub-Saharan countries.However,more remains to be known ...Background Prompt and appropriate clinical management of malaria is critical for reducing the continued high burden of malaria among children under five years in sub-Saharan countries.However,more remains to be known about how a patient’s socioeconomic status(SES)would affect the access to diagnosis of malaria.Methods In this cross-sectional study using the Demographic and Health Survey and Malaria Indicators Survey,we pooled the data of 38,567 febrile under-five children in 2016–2018 from 19 sub-Saharan countries.Multivariable logistic regression was used to assess the associations between SES and two binary outcomes:the visit to a health facility and a blood test for fever.Stratified analyses were further conducted by the type of health facilities(public hospitals/public primary healthcare facilities/private hospitals/private primary healthcare facilities)for the latter outcome.Results Fifty-eight percent of the febrile children were taken to health facilities,among whom only 55%took blood tests.Compared to children from households in the highest wealth quintile,children in the lowest quintile were less likely to be taken to medical facilities[adjusted odds ratio(aOR)=0.775,95%confidence interval(CI):0.675–0.889].Parents with more than secondary education were more likely to seek care(aOR=1.830,95%CI:1.561–2.145)and to have blood tests(aOR=1.729,95%CI:1.436–2.082)for their febrile children than parents without formal education.The probabilities of receiving blood tests at public hospitals and public primary healthcare facilities stayed relatively high across parental education levels and wealth quintiles,while these probabilities remained the lowest at private primary healthcare facilities,ranging from 0.100(95%CI:0.074–0.127)to 0.139(95%CI:0.083–0.194)across parental education levels and from 0.104(95%CI:0.078–0.130)to 0.125(95%CI:0.090–0.160)across wealth quintiles.Conclusions Significant socioeconomic disparities existed both in the access to health facilities and laboratory diagnosis of malaria in children in sub-Saharan African countries.These disparities were particularly evident in the private sector.Universal health coverage needs to be further strengthened to make formal healthcare in general and the laboratory diagnosis of malaria more accessible and affordable.展开更多
The 2008 Wenchuan Earthquake caused tremendous casualties and property losses as well as a substantial need for rebuilding the affected localities in order to address housing and urban development issues for the futur...The 2008 Wenchuan Earthquake caused tremendous casualties and property losses as well as a substantial need for rebuilding the affected localities in order to address housing and urban development issues for the future. China’s central government applied a national planning approach in both the emergency response and the disaster recovery phases that aims at facilitating the flow of technological assistance and financial aid from the whole country to the earthquake-stricken areas. This study reviews disaster management practices in China with an interdisciplinary analysis to see how disaster planning and management can be fit into the top-down government administration system. The Overall Plan for Post-Wenchuan Earthquake Recovery and Reconstruction and the City/Town System Plan for PostWenchuan Earthquake Recovery and Reconstruction, two overarching plans initiated by the central government, are evaluated by reviewing the underlying facts, goals, and actions. The plans’ merits are to be found in their incorporating hazard mitigation into disaster recovery plans and taking into account different strategies of relocation and reconstruction. The article also identifies the gap between making plans and meeting local needs, the insufficiency of public engagement in plan-making, and the negative planning impacts of competition for resources and funds. Suggestions for disaster planning and policy-making are provided with a focus on building a local disaster management system in China.展开更多
基金supported by the National MCF Energy R&D Program of China(No.2018YFE0303100)National Natural Science Foundation of China(No.11975038)。
文摘The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state discharge.The active control of inward particle transport is considered as one of the most critical issues of magnetic confinement fusion.Recently,it is realized preliminarily by adding a biased endplate in the Peking University Plasma Test(PPT)device.The results reveal that the inward particle flux increases with the bias voltage of the endplate.It is also found that the profile of radial electric field(Er)shear is flattened by the increased bias voltage.Radial velocity fluctuations affect the inward particle more than density fluctuations,and the frequency of the dominant mode driving inward particle flux increases with the biased voltage applied to the endplate.The experimental results in the PPT device provide a method to actively control the inward particle flux using a biased endplate and enrich the understanding of the relationship between E_(r)×B shear and turbulence transport.
基金supported by National Natural Science Foundation of China(No.11975038)the National MCF Energy R&D Program of China(Nos.2017YFE0300601 and 2018YFE0311400).
文摘The waves in a magnetic null could play important roles during 3D magnetic reconnection.Some preliminary clues in this paper show that the ion Bernstein wave(IBW)may be closely related to transport process in magnetic null region.The magnetic null configuration experiment reported here is set up in a linear helicon plasma device,Peking University plasma test device(PPT).The wave modes with frequencies between the first and third harmonics of local ion cyclotron frequency(w_(ci))are observed in the separatrix of magnetic null,which are identified as the IBW based on the dispersion relation.Further analysis shows that IBW could drive substantial particle flux across the magnetic separatrix.The theoretical radial particle flux driven by IBW and the measured parallel flow in PPT device are almost on the same order,which shows that IBW may play an important role during 3D reconnection process.
文摘Background Prompt and appropriate clinical management of malaria is critical for reducing the continued high burden of malaria among children under five years in sub-Saharan countries.However,more remains to be known about how a patient’s socioeconomic status(SES)would affect the access to diagnosis of malaria.Methods In this cross-sectional study using the Demographic and Health Survey and Malaria Indicators Survey,we pooled the data of 38,567 febrile under-five children in 2016–2018 from 19 sub-Saharan countries.Multivariable logistic regression was used to assess the associations between SES and two binary outcomes:the visit to a health facility and a blood test for fever.Stratified analyses were further conducted by the type of health facilities(public hospitals/public primary healthcare facilities/private hospitals/private primary healthcare facilities)for the latter outcome.Results Fifty-eight percent of the febrile children were taken to health facilities,among whom only 55%took blood tests.Compared to children from households in the highest wealth quintile,children in the lowest quintile were less likely to be taken to medical facilities[adjusted odds ratio(aOR)=0.775,95%confidence interval(CI):0.675–0.889].Parents with more than secondary education were more likely to seek care(aOR=1.830,95%CI:1.561–2.145)and to have blood tests(aOR=1.729,95%CI:1.436–2.082)for their febrile children than parents without formal education.The probabilities of receiving blood tests at public hospitals and public primary healthcare facilities stayed relatively high across parental education levels and wealth quintiles,while these probabilities remained the lowest at private primary healthcare facilities,ranging from 0.100(95%CI:0.074–0.127)to 0.139(95%CI:0.083–0.194)across parental education levels and from 0.104(95%CI:0.078–0.130)to 0.125(95%CI:0.090–0.160)across wealth quintiles.Conclusions Significant socioeconomic disparities existed both in the access to health facilities and laboratory diagnosis of malaria in children in sub-Saharan African countries.These disparities were particularly evident in the private sector.Universal health coverage needs to be further strengthened to make formal healthcare in general and the laboratory diagnosis of malaria more accessible and affordable.
基金The research for this article was supported by the Program of Introducing Talents of Discipline to Universities(B08008)and the State Key Laboratory of Earth Surface Processes and Resource Ecology at Beijing Normal University,China.
文摘The 2008 Wenchuan Earthquake caused tremendous casualties and property losses as well as a substantial need for rebuilding the affected localities in order to address housing and urban development issues for the future. China’s central government applied a national planning approach in both the emergency response and the disaster recovery phases that aims at facilitating the flow of technological assistance and financial aid from the whole country to the earthquake-stricken areas. This study reviews disaster management practices in China with an interdisciplinary analysis to see how disaster planning and management can be fit into the top-down government administration system. The Overall Plan for Post-Wenchuan Earthquake Recovery and Reconstruction and the City/Town System Plan for PostWenchuan Earthquake Recovery and Reconstruction, two overarching plans initiated by the central government, are evaluated by reviewing the underlying facts, goals, and actions. The plans’ merits are to be found in their incorporating hazard mitigation into disaster recovery plans and taking into account different strategies of relocation and reconstruction. The article also identifies the gap between making plans and meeting local needs, the insufficiency of public engagement in plan-making, and the negative planning impacts of competition for resources and funds. Suggestions for disaster planning and policy-making are provided with a focus on building a local disaster management system in China.