Traffic flow prediction plays a key role in the construction of intelligent transportation system.However,due to its complex spatio-temporal dependence and its uncertainty,the research becomes very challenging.Most of...Traffic flow prediction plays a key role in the construction of intelligent transportation system.However,due to its complex spatio-temporal dependence and its uncertainty,the research becomes very challenging.Most of the existing studies are based on graph neural networks that model traffic flow graphs and try to use fixed graph structure to deal with the relationship between nodes.However,due to the time-varying spatial correlation of the traffic network,there is no fixed node relationship,and these methods cannot effectively integrate the temporal and spatial features.This paper proposes a novel temporal-spatial dynamic graph convolutional network(TSADGCN).The dynamic time warping algorithm(DTW)is introduced to calculate the similarity of traffic flow sequence among network nodes in the time dimension,and the spatiotemporal graph of traffic flow is constructed to capture the spatiotemporal characteristics and dependencies of traffic flow.By combining graph attention network and time attention network,a spatiotemporal convolution block is constructed to capture spatiotemporal characteristics of traffic data.Experiments on open data sets PEMSD4 and PEMSD8 show that TSADGCN has higher prediction accuracy than well-known traffic flow prediction algorithms.展开更多
Many existing studies have considered the factors influencing review helpfulness,mainly focusing on reviewer impact,review informativeness,and managerial response,based on signaling theory.However,previous studies hav...Many existing studies have considered the factors influencing review helpfulness,mainly focusing on reviewer impact,review informativeness,and managerial response,based on signaling theory.However,previous studies have simply regarded these factors as independent signals,thus ignoring their in-depth transmission and reception processes.The conclusions about the impact of reviewers on review helpfulness are also inconsistent due to the inaccurate measure-ment of variables.To fill the above gaps,we followed the signaling timeline theoretical framework used in signaling the-ory and employed a bootstrapping analysis to examine how reviewer impact,review informativeness,and hotel manageri-al responses interact to influence review helpfulness.In this study,we used a unique dataset that included official labels from one leading online travel agency.The results show that reviewer impact may affect review helpfulness sequentially through review informativeness and hotel managerial response.Furthermore,by using official labels,both reviewer expert-ise and reviewer experience significantly affect review helpfulness.Finally,we discussed the theoretical and practical im-plications of these findings.展开更多
We study the effect of strain on band structure and valley-dependent transport properties of graphene heterojunctions.It is found that valley-dependent separation of electrons can be achieved by utilizing strain and o...We study the effect of strain on band structure and valley-dependent transport properties of graphene heterojunctions.It is found that valley-dependent separation of electrons can be achieved by utilizing strain and on-site energies.In the presence of strain,the values of transmission can be effectively adjusted by changing the strengths of the strain,while the transport angle basically keeps unchanged.When an extra on-site energy is simultaneously applied to the central scattering region,not only are the electrons of valleys K and K'separated into two distinct transmission lobes in opposite transverse directions,but the transport angles of two valleys can be significantly changed.Therefore,one can realize an effective modulation of valley-dependent transport by changing the strength and stretch angle of the strain and on-site energies,which can be exploited for graphene-based valleytronics devices.展开更多
We study electrical modulation of transport properties of silicene nanoconstrictions with different geometrical structures.We investigate the effects of the position and width of the central scattering region on the c...We study electrical modulation of transport properties of silicene nanoconstrictions with different geometrical structures.We investigate the effects of the position and width of the central scattering region on the conductance with increasing Fermi energy.It is found that the conductance significantly depends on the position and the width of the nanoconstriction.Interestingly,the symmetrical structure of the central constriction region can induce a resonance effect and significantly increase the system’s conductance.We also propose a novel two-channel structure with an excellent performance on the conductance compared to the one-channel structure with the same total width.Such geometrically-induced conductance modulation of silicene nanostructures can be achieved in practice via current nanofabrication technology.展开更多
The electrosynthesis of hydrogen peroxide is limited by the competitive four-electron oxygen reduction reaction(ORR)pathway.The modulation for the adsorption of OOH^(*)intermediate on active sites is considered as the...The electrosynthesis of hydrogen peroxide is limited by the competitive four-electron oxygen reduction reaction(ORR)pathway.The modulation for the adsorption of OOH^(*)intermediate on active sites is considered as the effective approach to tune the ORR selectivity,but it remains challenging.Herein,we report the neighboring phosphorus atom in the second coordination shell to regulate the electronic structure of the isolated Ni-N_(4) sites,leading to the favored OOH^(*)adsorption and thus boosting the electrocatalytic ORR to hydrogen peroxide through the two-electron pathway.Spectroscopy characterizations and density functional theory calculations indicate the neighboring phosphorus atom in the second coordination shell triggers the electron transfer to central Ni atom,strengthening the adsorption of OOH^(*)on Ni sites and thus increasing the catalytic performance for two-electron ORR,delivering a selectivity above 90%for production of hydrogen peroxide under the current density of 150 mA·cm^(−2).This work reveals tailoring second coordination shell of isolated metal sites could be as a precise and efficient way to engineer the catalytic performance,which thus provides a promising approach to the design of advanced catalysts.展开更多
DNA computing, currently a hot research field in information processing, has the advantages of parallelism, low energy consumption, and high storability, therefore, it has been applied to a variety of complicated comp...DNA computing, currently a hot research field in information processing, has the advantages of parallelism, low energy consumption, and high storability, therefore, it has been applied to a variety of complicated computational problems. The emerging field of DNA nanotechnology has also developed quickly; within it, the method of DNA strand displacement has drawn great attention because it is self-induced, sensitive, accurate, and operationally simple. This article summarizes five aspects of the recent developments of DNA-strand displacement in DNA computing:(1) cascading circuits;(2) catalyzed reaction;(3) logic computation;(4) DNA computing on surfaces; and(5) logic computing based on nanoparticles guided by strand displacement. The applications and mechanisms of strand displacement in DNA computing are discussed and possible future developments are presented.展开更多
In order to improve the simulation accuracy for free-fall lifeboat in ship life-saving training system,this paper analyzes and models the motion of boat’s launching from the skid.The whole launching is divided into f...In order to improve the simulation accuracy for free-fall lifeboat in ship life-saving training system,this paper analyzes and models the motion of boat’s launching from the skid.The whole launching is divided into four phases,namely:sliding down,rotation,free fall and water entry.According to the theory of momentum and strip theory,hydrodynamic forces of the boat at water entry are calculated under the effect of waves.The method of interpolation is used for calculating the half width and added mass of cross-sections at water entry.The model is used for numerical investigation about the boat launching from skid under different conditions and applied to ship life-saving simulation training system.The following conclusions are finally obtained:(1)When the initial inclination angle is 30◦,the horizontal distance between the point of water entry of the boat and the lower end of the slide is about 7.2 m.The horizontal distance will be smaller,when the initial inclination angle increases.There is no obvious law between forward distance and waves.(2)When the initial inclination angle is 45◦,the setback may occur after the boat entering the wave.When the initial angle is 60◦,the setback occurs after the boat entering the water.(3)When the center of gravity is 1.5 m in front of the midship of the boat,the boat will turn over.展开更多
基金supported by the National Natural Science Foundation of China(Grant:62176086).
文摘Traffic flow prediction plays a key role in the construction of intelligent transportation system.However,due to its complex spatio-temporal dependence and its uncertainty,the research becomes very challenging.Most of the existing studies are based on graph neural networks that model traffic flow graphs and try to use fixed graph structure to deal with the relationship between nodes.However,due to the time-varying spatial correlation of the traffic network,there is no fixed node relationship,and these methods cannot effectively integrate the temporal and spatial features.This paper proposes a novel temporal-spatial dynamic graph convolutional network(TSADGCN).The dynamic time warping algorithm(DTW)is introduced to calculate the similarity of traffic flow sequence among network nodes in the time dimension,and the spatiotemporal graph of traffic flow is constructed to capture the spatiotemporal characteristics and dependencies of traffic flow.By combining graph attention network and time attention network,a spatiotemporal convolution block is constructed to capture spatiotemporal characteristics of traffic data.Experiments on open data sets PEMSD4 and PEMSD8 show that TSADGCN has higher prediction accuracy than well-known traffic flow prediction algorithms.
基金supported by the Philosophy and Social Science Planning Program of Shanghai(2021BGL018).
文摘Many existing studies have considered the factors influencing review helpfulness,mainly focusing on reviewer impact,review informativeness,and managerial response,based on signaling theory.However,previous studies have simply regarded these factors as independent signals,thus ignoring their in-depth transmission and reception processes.The conclusions about the impact of reviewers on review helpfulness are also inconsistent due to the inaccurate measure-ment of variables.To fill the above gaps,we followed the signaling timeline theoretical framework used in signaling the-ory and employed a bootstrapping analysis to examine how reviewer impact,review informativeness,and hotel manageri-al responses interact to influence review helpfulness.In this study,we used a unique dataset that included official labels from one leading online travel agency.The results show that reviewer impact may affect review helpfulness sequentially through review informativeness and hotel managerial response.Furthermore,by using official labels,both reviewer expert-ise and reviewer experience significantly affect review helpfulness.Finally,we discussed the theoretical and practical im-plications of these findings.
基金National Natural Science Foundation of China(Grant No.11574067)。
文摘We study the effect of strain on band structure and valley-dependent transport properties of graphene heterojunctions.It is found that valley-dependent separation of electrons can be achieved by utilizing strain and on-site energies.In the presence of strain,the values of transmission can be effectively adjusted by changing the strengths of the strain,while the transport angle basically keeps unchanged.When an extra on-site energy is simultaneously applied to the central scattering region,not only are the electrons of valleys K and K'separated into two distinct transmission lobes in opposite transverse directions,but the transport angles of two valleys can be significantly changed.Therefore,one can realize an effective modulation of valley-dependent transport by changing the strength and stretch angle of the strain and on-site energies,which can be exploited for graphene-based valleytronics devices.
基金Supported by the National Natural Science Foundation of China(Grant No.11574067)。
文摘We study electrical modulation of transport properties of silicene nanoconstrictions with different geometrical structures.We investigate the effects of the position and width of the central scattering region on the conductance with increasing Fermi energy.It is found that the conductance significantly depends on the position and the width of the nanoconstriction.Interestingly,the symmetrical structure of the central constriction region can induce a resonance effect and significantly increase the system’s conductance.We also propose a novel two-channel structure with an excellent performance on the conductance compared to the one-channel structure with the same total width.Such geometrically-induced conductance modulation of silicene nanostructures can be achieved in practice via current nanofabrication technology.
基金financially supported by the Taishan Scholar Project Foundation of Shandong Province(Nos.tsqn202211028 and tsqn202306080)the Natural Science Foundation of Shandong Province(Nos.ZR2022JQ08 and 2023HWYQ-028)the Instrument Improvement Founds of Shandong University Public Technology Platform(No.ts20230209).
文摘The electrosynthesis of hydrogen peroxide is limited by the competitive four-electron oxygen reduction reaction(ORR)pathway.The modulation for the adsorption of OOH^(*)intermediate on active sites is considered as the effective approach to tune the ORR selectivity,but it remains challenging.Herein,we report the neighboring phosphorus atom in the second coordination shell to regulate the electronic structure of the isolated Ni-N_(4) sites,leading to the favored OOH^(*)adsorption and thus boosting the electrocatalytic ORR to hydrogen peroxide through the two-electron pathway.Spectroscopy characterizations and density functional theory calculations indicate the neighboring phosphorus atom in the second coordination shell triggers the electron transfer to central Ni atom,strengthening the adsorption of OOH^(*)on Ni sites and thus increasing the catalytic performance for two-electron ORR,delivering a selectivity above 90%for production of hydrogen peroxide under the current density of 150 mA·cm^(−2).This work reveals tailoring second coordination shell of isolated metal sites could be as a precise and efficient way to engineer the catalytic performance,which thus provides a promising approach to the design of advanced catalysts.
基金supported by the National Natural Science Foundation of China(61272246,61370099,61272161,61127005,61133010,61425002,61320106005)the Graduate Education in Shaanxi Normal University Innovation Fund
文摘DNA computing, currently a hot research field in information processing, has the advantages of parallelism, low energy consumption, and high storability, therefore, it has been applied to a variety of complicated computational problems. The emerging field of DNA nanotechnology has also developed quickly; within it, the method of DNA strand displacement has drawn great attention because it is self-induced, sensitive, accurate, and operationally simple. This article summarizes five aspects of the recent developments of DNA-strand displacement in DNA computing:(1) cascading circuits;(2) catalyzed reaction;(3) logic computation;(4) DNA computing on surfaces; and(5) logic computing based on nanoparticles guided by strand displacement. The applications and mechanisms of strand displacement in DNA computing are discussed and possible future developments are presented.
基金The authors thank the financial support provided by National Natural Science Foundation of China(Grant No.52071312)Liaoning Provincial Natural Science Foundation shipping joint fund project(Grant No.2020-HYLH-29)Provincial postgraduate education and teaching achievement award cultivation project(Grant No.YJG2020601).
文摘In order to improve the simulation accuracy for free-fall lifeboat in ship life-saving training system,this paper analyzes and models the motion of boat’s launching from the skid.The whole launching is divided into four phases,namely:sliding down,rotation,free fall and water entry.According to the theory of momentum and strip theory,hydrodynamic forces of the boat at water entry are calculated under the effect of waves.The method of interpolation is used for calculating the half width and added mass of cross-sections at water entry.The model is used for numerical investigation about the boat launching from skid under different conditions and applied to ship life-saving simulation training system.The following conclusions are finally obtained:(1)When the initial inclination angle is 30◦,the horizontal distance between the point of water entry of the boat and the lower end of the slide is about 7.2 m.The horizontal distance will be smaller,when the initial inclination angle increases.There is no obvious law between forward distance and waves.(2)When the initial inclination angle is 45◦,the setback may occur after the boat entering the wave.When the initial angle is 60◦,the setback occurs after the boat entering the water.(3)When the center of gravity is 1.5 m in front of the midship of the boat,the boat will turn over.
