An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street blocks.Hazard sources not only physically but psychologically affect the ped...An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street blocks.Hazard sources not only physically but psychologically affect the pedestrians,which may further alter their behavioral patterns.This effect is especially significant in narrow spaces,such as corridors and alleys.This study aims to integrate a non-spreading hazard source into the social force model following the results from a previous experiment and simulation,and to simulate unidirectional pedestrian flows over various crowd densities and clarity–intensity properties of the hazard source.The integration include a virtual repulsion force from the hazard source and a decay on the social force term.The simulations reveal(i)that the hazard source creates virtual bottlenecks that suppress the flow,(ii)that the inter-pedestrian push forms a stabilisation phase on the flow-density curve within medium-to-high densities,and(iii)that the pedestrians are prone to a less orderly and stable pattern of movement in low clarity–intensity scenarios,possibly with lateral collisions passing the hazard source.展开更多
External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper preventi...External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper prevention and control measures.We reviewed literature on risk identification of underground pressure pipelines damage due to external disturbance was conducted,and a list of risk factors was formed.Based on the list of risk factors,fault tree analysis was carried out on underground pressure pipelines damage caused by external disturbances,and risk prevention and control measures were proposed through the calculation of minimum cut sets,minimum path sets,and structural importance,in hopes of providing reference for the normal operation of underground pressure pipelines.展开更多
Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution problems.The key issue is the development o...Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution problems.The key issue is the development of high-efficiency photocatalysts.Various strategies in the state-of-the-art advancements,such as heterostructure construction,heteroatom doping,metal/single atom loading,and defect engineering,have been presented for the graphitic carbon nitride(g-C3N4)-based nanocomposite catalysts to design their surface chemical environments and internal electronic structures to make them more suitable for different photocatalytic applications.In this review,nanoarchitecture design,synthesis methods,photochemical properties,potential photocatalytic applications,and related reaction mechanisms of the modified high-efficiency carbon nitride-based photocatalysts were briefly summarized.The superior photocatalytic performance was identified to be associated with the enhanced visible-light response,fast photoinduced electron-hole separation,efficient charge migration,and increased unsaturated active sites.Moreover,the further advance of the visible-light harvesting and solar-to-energy conversions are proposed.展开更多
基金Project supported by National Key Research and Development Program of China(Grant Nos.2022YFC3320800 and 2021YFC1523500)the National Natural Science Foundation of China(Grant Nos.71971126,71673163,72304165,72204136,and 72104123).
文摘An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street blocks.Hazard sources not only physically but psychologically affect the pedestrians,which may further alter their behavioral patterns.This effect is especially significant in narrow spaces,such as corridors and alleys.This study aims to integrate a non-spreading hazard source into the social force model following the results from a previous experiment and simulation,and to simulate unidirectional pedestrian flows over various crowd densities and clarity–intensity properties of the hazard source.The integration include a virtual repulsion force from the hazard source and a decay on the social force term.The simulations reveal(i)that the hazard source creates virtual bottlenecks that suppress the flow,(ii)that the inter-pedestrian push forms a stabilisation phase on the flow-density curve within medium-to-high densities,and(iii)that the pedestrians are prone to a less orderly and stable pattern of movement in low clarity–intensity scenarios,possibly with lateral collisions passing the hazard source.
基金This project was funded by Consulting Research Project of Chinese Academy of Engineering:Research on Innovative Development Strategy of Urban Safety Engineering(Project number:2020-02)。
文摘External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper prevention and control measures.We reviewed literature on risk identification of underground pressure pipelines damage due to external disturbance was conducted,and a list of risk factors was formed.Based on the list of risk factors,fault tree analysis was carried out on underground pressure pipelines damage caused by external disturbances,and risk prevention and control measures were proposed through the calculation of minimum cut sets,minimum path sets,and structural importance,in hopes of providing reference for the normal operation of underground pressure pipelines.
基金supported by the Natural Science Foundation of Anhui Province (No. 1908085ME165)the Anhui Provincial Natural Science Key Foundation (No. 2008085UD07)the Special Funds for the Development of Local Science and Technology from the Central Government in Anhui Province (No. 803214271050)
文摘Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution problems.The key issue is the development of high-efficiency photocatalysts.Various strategies in the state-of-the-art advancements,such as heterostructure construction,heteroatom doping,metal/single atom loading,and defect engineering,have been presented for the graphitic carbon nitride(g-C3N4)-based nanocomposite catalysts to design their surface chemical environments and internal electronic structures to make them more suitable for different photocatalytic applications.In this review,nanoarchitecture design,synthesis methods,photochemical properties,potential photocatalytic applications,and related reaction mechanisms of the modified high-efficiency carbon nitride-based photocatalysts were briefly summarized.The superior photocatalytic performance was identified to be associated with the enhanced visible-light response,fast photoinduced electron-hole separation,efficient charge migration,and increased unsaturated active sites.Moreover,the further advance of the visible-light harvesting and solar-to-energy conversions are proposed.
