Materials with kagome lattices have attracted significant research attention due to their nontrivial features in energy bands.We theoretically investigate the evolution of electronic band structures of kagome lattices...Materials with kagome lattices have attracted significant research attention due to their nontrivial features in energy bands.We theoretically investigate the evolution of electronic band structures of kagome lattices in response to uniaxial strain using both a tight-binding model and an antidot model based on a periodic muffin-tin potential.It is found that the Dirac points move with applied strain.Furthermore,the flat band of unstrained kagome lattices is found to develop into a highly anisotropic shape under a stretching strain along y direction,forming a partially flat band with a region dispersionless along ky direction while dispersive along kx direction.Our results shed light on the possibility of engineering the electronic band structures of kagome materials by mechanical strain.展开更多
Introduction:Substantial evidence indicates that electronic cigarettes(e-cigarettes)pose considerable health risks to the human body.There is a lack of surveillance data regarding adult e-cigarette use behavior in Bei...Introduction:Substantial evidence indicates that electronic cigarettes(e-cigarettes)pose considerable health risks to the human body.There is a lack of surveillance data regarding adult e-cigarette use behavior in Beijing.Methods:This study utilizes the 2016–2023 Beijing Adult Tobacco Survey data to assess the current status,changing trends,and influencing factors of e-cigarette use among urban and rural residents aged≥15 years across 16 districts of Beijing Municipality.All statistical analyses incorporated complex sampling weights.Results:The prevalence of e-cigarette ever use among Beijing residents aged≥15 years was 5.7%,8.1%,8.6%,and 6.9%in 2016,2019,2021,and 2023,respectively,while current use prevalence was 1.6%,2.1%,2.7%,and 1.8%,respectively.Males,younger individuals,those with higher educational attainment,and those living alone demonstrated greater odds of e-cigarette use.Current smokers who had attempted to quit within the past 12 months showed the highest odds of use,followed by current smokers without quit attempts and former smokers who had quit for less than 12 months.Conclusions:The public are not fully aware of the academic and clinical controversies regarding ecigarettes’effectiveness for smoking cessation and may underestimate their health risks.There is an urgent need for targeted knowledge campaigns addressing these misconceptions and for the provision of more accessible smoking cessation services.展开更多
The measurement-result-conditioned evolution of a system(e.g., an atom) with spontaneous emissions of photons is described by the quantum trajectory(QT) theory. In this work we generalize the associated QT theory from...The measurement-result-conditioned evolution of a system(e.g., an atom) with spontaneous emissions of photons is described by the quantum trajectory(QT) theory. In this work we generalize the associated QT theory from an infinitely wide bandwidth Markovian environment to the finite bandwidth non-Markovian environment. In particular, we generalize the treatment for an arbitrary spectrum, which is not restricted by the specific Lorentzian case. We rigorously prove the general existence of a perfect scaling behavior jointly defined by the bandwidth of the environment and the time interval between successive photon detections.For a couple of examples, we obtain analytic results to facilitate the QT simulations based on the Monte-Carlo algorithm. For the case where the analytical result is not available, a numerical scheme is proposed for practical simulations.展开更多
Solar energy is a commonly used renewable energy source in buildings.In the highaltitude mountainous regions of western Sichuan,solar energy resources are abundant,but the complex and variable terrain significantly af...Solar energy is a commonly used renewable energy source in buildings.In the highaltitude mountainous regions of western Sichuan,solar energy resources are abundant,but the complex and variable terrain significantly affects the shading of solar radiation on building roofs.In the mountainous regions of western Sichuan,towns located in valley terrain are the most prevalent,accounting for as much as 42.14%.Therefore,based on the mountainous solar radiation estimation method,this study estimates the direct radiation shading rate and diffuse radiation shading rate for building roofs in the valley towns of western Sichuan.The research delves into the analysis of the impact of valley terrain characteristics on the shading of solar radiation on building roofs.The study reveals that,for a specific valley town,the orientation of the valley has a more significant impact on the shading of direct radiation compared to its impact on diffuse radiation.When the town's orientation approaches an east-west direction,both direct and diffuse radiations are less affected by terrain shading.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11904261 and 11904259).
文摘Materials with kagome lattices have attracted significant research attention due to their nontrivial features in energy bands.We theoretically investigate the evolution of electronic band structures of kagome lattices in response to uniaxial strain using both a tight-binding model and an antidot model based on a periodic muffin-tin potential.It is found that the Dirac points move with applied strain.Furthermore,the flat band of unstrained kagome lattices is found to develop into a highly anisotropic shape under a stretching strain along y direction,forming a partially flat band with a region dispersionless along ky direction while dispersive along kx direction.Our results shed light on the possibility of engineering the electronic band structures of kagome materials by mechanical strain.
文摘Introduction:Substantial evidence indicates that electronic cigarettes(e-cigarettes)pose considerable health risks to the human body.There is a lack of surveillance data regarding adult e-cigarette use behavior in Beijing.Methods:This study utilizes the 2016–2023 Beijing Adult Tobacco Survey data to assess the current status,changing trends,and influencing factors of e-cigarette use among urban and rural residents aged≥15 years across 16 districts of Beijing Municipality.All statistical analyses incorporated complex sampling weights.Results:The prevalence of e-cigarette ever use among Beijing residents aged≥15 years was 5.7%,8.1%,8.6%,and 6.9%in 2016,2019,2021,and 2023,respectively,while current use prevalence was 1.6%,2.1%,2.7%,and 1.8%,respectively.Males,younger individuals,those with higher educational attainment,and those living alone demonstrated greater odds of e-cigarette use.Current smokers who had attempted to quit within the past 12 months showed the highest odds of use,followed by current smokers without quit attempts and former smokers who had quit for less than 12 months.Conclusions:The public are not fully aware of the academic and clinical controversies regarding ecigarettes’effectiveness for smoking cessation and may underestimate their health risks.There is an urgent need for targeted knowledge campaigns addressing these misconceptions and for the provision of more accessible smoking cessation services.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0303304)the National Natural Science Foundation of China(Grant No.11675016)
文摘The measurement-result-conditioned evolution of a system(e.g., an atom) with spontaneous emissions of photons is described by the quantum trajectory(QT) theory. In this work we generalize the associated QT theory from an infinitely wide bandwidth Markovian environment to the finite bandwidth non-Markovian environment. In particular, we generalize the treatment for an arbitrary spectrum, which is not restricted by the specific Lorentzian case. We rigorously prove the general existence of a perfect scaling behavior jointly defined by the bandwidth of the environment and the time interval between successive photon detections.For a couple of examples, we obtain analytic results to facilitate the QT simulations based on the Monte-Carlo algorithm. For the case where the analytical result is not available, a numerical scheme is proposed for practical simulations.
文摘Solar energy is a commonly used renewable energy source in buildings.In the highaltitude mountainous regions of western Sichuan,solar energy resources are abundant,but the complex and variable terrain significantly affects the shading of solar radiation on building roofs.In the mountainous regions of western Sichuan,towns located in valley terrain are the most prevalent,accounting for as much as 42.14%.Therefore,based on the mountainous solar radiation estimation method,this study estimates the direct radiation shading rate and diffuse radiation shading rate for building roofs in the valley towns of western Sichuan.The research delves into the analysis of the impact of valley terrain characteristics on the shading of solar radiation on building roofs.The study reveals that,for a specific valley town,the orientation of the valley has a more significant impact on the shading of direct radiation compared to its impact on diffuse radiation.When the town's orientation approaches an east-west direction,both direct and diffuse radiations are less affected by terrain shading.
