Objectives:Suicidal ideation(SI)among university students is a growing concern,influenced by anxiety,depression,and bullying.However,family closeness and peer support may act as protective factors,reducing the risk of...Objectives:Suicidal ideation(SI)among university students is a growing concern,influenced by anxiety,depression,and bullying.However,family closeness and peer support may act as protective factors,reducing the risk of SI.Therefore,this study aims to investigate the key factors influencing SI among university students,focusing on the effects of anxiety,depression,and bullying,along with the roles of family closeness and peer support.The research also explores the interactions and mechanisms between these variables.Methods:A sample of 318 university students was surveyed,evaluating six main factors:anxiety,depression,bullying,family closeness,peer support,and SI.Using the Structural Equation Modeling(SEM)and Artificial Neural Networks(ANN)approach,both compensatory and non-compensatory relationships were examined.Results:Anxiety,depression,and bullying significantly contribute to SI,with depression mediating the link between anxiety,bullying,and SI.Additionally,family closeness moderates the effects of anxiety and bullying on SI,while peer supportmoderates the effects of depression and bullying.Themultilayer perceptron analysis identifies peer support as the most influential predictor,followed by bullying,family closeness,depression,and anxiety.Conclusion:The study identifies anxiety,depression,and bullying as key factors influencing suicidal ideation(SI)among university students.Family closeness and peer support act as protective factors,moderating the effects of these variables on SI.展开更多
Based on the theory of pattern recognition, the concept of closeness degree between fuzzy sets is brought into the condition assessment of long span bridges. Using the fuzzy analytic hierarchy process （FAHP）, a math...Based on the theory of pattern recognition, the concept of closeness degree between fuzzy sets is brought into the condition assessment of long span bridges. Using the fuzzy analytic hierarchy process （FAHP）, a mathematical model of a multi-objective assessment of a long span suspension bridge is set up. An example is given to show the procedure in the synthetical condition assessment of the Runyang Suspension Bridge, which includes the hierarchical division, the definition of factor weights and fuzzy membership functions, and the calculation of closeness degrees, etc. The assessment combines both the data from the health monitoring system and the manual tests. The classification of evaluation items as well as the calculation of deterministic and nondeterministic items is presented. Compared with the traditional method of point rating, this method can better describe the discreteness of monitoring data and the fuzziness in the condition assessment.展开更多
The main activities in project portfolio allocation management are selecting the right project components given a strategy. It is crucial to establish a scientific system of evaluation indexes to guarantee the closene...The main activities in project portfolio allocation management are selecting the right project components given a strategy. It is crucial to establish a scientific system of evaluation indexes to guarantee the closeness between strategy and project portfolio allocation optimally. With organizations growing in sizes, the functions and objectives of project components are becoming more and more different. It is necessary to set evaluation indexes of the degree of closeness from the perspectives of financial, market share, social effects, and so on according to the strategy-oriented process of project portfolio allocation. This paper proposes a project portfolio allocation process under strategic orientation and evaluation indexes of the degree of closeness between strategy and project portfolio allocation. This will help projects managers make portfolio allocation decisions.展开更多
Is one knowing about their parents’social lives associated with how close they are to them?An obvious answer might be yes.We first found that in a sample of Chinese students,they are more aware of the number of frien...Is one knowing about their parents’social lives associated with how close they are to them?An obvious answer might be yes.We first found that in a sample of Chinese students,they are more aware of the number of friends their mother has tham the friends their dads have.We then found that,for girls,knowing their mom and dad's friends predicts closeness with dad.Closeness to mother is not associated with knowledge of either parents’social network.For boys,however,knowing mothers’friends(but not the father’s friends)predicts their closeness to the father.As with girls,knowing either parent’s network is not associated with maternal closeness.This research implies that there are different ways closeness emerges between mothers and fathers and their children.展开更多
Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells ...Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.展开更多
Network virtualization aims to provide a way to overcome ossification of the Internet. However, making efficient use of substrate resources requires effective techniques for embedding virtual networks： mapping virtua...Network virtualization aims to provide a way to overcome ossification of the Internet. However, making efficient use of substrate resources requires effective techniques for embedding virtual networks： mapping virtual nodes and virtual edges onto substrate networks. Previous research has presented several heuristic algorithms, which fail to consider that the attributes of the substrate topology and virtual net- works affect the embedding process. In this paper, for the first time, we introduce complex network centrality analysis into the virtual network embedding, and propose virtual network embedding algorithms based on closeness centrality. Due to considering of the attributes of nodes and edges in the topology, our studies are more reasonable than existing work. In addition, with the guidance of topology quantitative evalua- tion, the proposed network embedding approach largely improves the network utilization efficiency and decreases the embedding complexity. We also investigate our algorithms on real network topologies （e.g., AT＆T, DFN） and random network topologies. Experimental results demonstrate the usability and capability of the proposed approach.展开更多
Pore structure engineering has been acknowledged as suitable approach to creating active sites and en-hancing ion transport capabilities of hard carbon anodes.However,conventional porous carbon materials exhibit high ...Pore structure engineering has been acknowledged as suitable approach to creating active sites and en-hancing ion transport capabilities of hard carbon anodes.However,conventional porous carbon materials exhibit high BET and surface defects.Additionally,the sodium storage mechanism predominantly occurs in the slope region.This contradicts practical application requirements because the capacity of the plateau region is crucial for determining the actual capacity of batteries.In our work,we prepared a novel“core-shell”carbon framework(CNA1200).Introducingclosedporesand carboxylgroupsinto coal-basedcarbon materials to enhance its sodium storage performance.The closed pore structure dominates in the“core”structure,which is attributed to the timely removal of sodium hydroxide(NaOH)to prevent further for-mation of active carbon structure.The presence of closed pores is beneficial for increasing sodium ion storage in the low-voltage plateau region.And the“shell”structure originates from coal tar pitch,it not only uniformly connects hard carbon particles together to improve cycling stability,but is also rich in carboxyl groups to enhance the reversible sodium storage performance in slope region.CNA1200 has ex-cellent electrochemical performance,it exhibits a specific capacity of 335.2 mAh g^(−1)at a current density of 20 mA g^(−1)with ICE=51.53%.In addition,CNA1200 has outstanding cycling stability with a capac-ity retention of 91.8%even when cycling over 200 times.When CNA1200 is used as anode paired with Na_(3)V_(2)(PO_(4))_(3)cathode,it demonstrates a capacity of 109.54 mAh g^(−1)at 0.1 C and capacity retention of 94.64%at 0.5 C.This work provides valuable methods for regulating the structure of sodium-ion battery(SIBs)anode and enhances the potential for commercialization.展开更多
Importance:Parent-infant closeness and active parent participation in neonatal care are important for parent and infant health.Objective:To give an overview of current neonatal settings and gain an in-depth understand...Importance:Parent-infant closeness and active parent participation in neonatal care are important for parent and infant health.Objective:To give an overview of current neonatal settings and gain an in-depth understanding of facilitators and barriers to parent-infant closeness,zero-separation,in 19 countries.Methods:Neonatal intensive care unit(NICU)professionals,representing 45 NICUs from a range of geographic regions in Europe and Canada,were purposefully selected and interviewed June–December 2018.Thematic analysis was conducted to identify,analyze and report patterns(themes)for parent-infant closeness across the entire series of interviews.Results:Parent-infant separation during infant and/or maternity care is very common(42/45 units,93%),despite the implementation of family integrated care(FICare)practices,including parent participation in medical rounds(17/45,38%),structured education sessions for parents(16/45,36%)and structured training for healthcare professionals(22/45,49%).NICU professionals encountered four main themes with facilitators and barriers for parent-infant closeness on and between the hospital,unit,staff,and family level:Culture(jointly held characteristics,values,thinking and behaviors about parental presence and participation in the unit),Collaboration(the act of working together between and within different levels),Capacities(resources and policies),andCoaching(education to acquire and transfer knowledge and skills).Interpretation:Implementing parent-infant closeness in the NICU is still challenging for healthcare professionals.Further optimization in neonatal care towards zero-separation and parent-infant closeness can be achieved by enforcing the’’four Cs for Closeness’:Culture,Collaboration,Capacities,andCoaching.展开更多
Rationally regulating the porosity of hard carbon(HC),especially the closed pores matching the low potential plateau and the ultra-microporous structure suitable for Na+embedding,has been shown to be the key to improv...Rationally regulating the porosity of hard carbon(HC),especially the closed pores matching the low potential plateau and the ultra-microporous structure suitable for Na+embedding,has been shown to be the key to improving the sodium storage performance and initial coulombic efficiency(ICE).However,the preparation of such HC materials with specific pore structures still faces great challenges.Herein,a simple pre-oxidation strategy is employed to construct abundant closed ultra-microporous structures in soy protein powder-derived HC material,achieving a significant improvement in its ICE and platform capacity.The pre-oxidation process promotes the cross-linking degree of the soy protein,thereby hindering the directional growth of graphite domains during the carbonization process.The optimized HC exhibits ultra-high platform capacity(329 mAh g^(-1))and considerable energy density(148.5 Wh kg^(-1)).Based on the ex-situ Raman and X-ray photoelectron spectroscopy characterization results,the excellent sodium storage capacity of the HC material is attributed to the synergistic effect of adsorption-intercalation/filling.The presented work provides novel insights into the synthesis of other biomass-derived HC materials with abundant closed ultra-micro pores.展开更多
Drawing on a tripartite perspective on attitudes, this study examines the influence of psychological ownership and territoriality on turnover intention, as well as the moderating role of work relationship closeness on...Drawing on a tripartite perspective on attitudes, this study examines the influence of psychological ownership and territoriality on turnover intention, as well as the moderating role of work relationship closeness on the relationship between territoriality and turnover intention. Analyses of longitudinal data collected from 341 employees in three Chinese automobile manufacturing companies demonstrate that employees＇ psychological ownership is negatively related to their turnover intention. As well, territoriality is negatively related to turnover intention and mediates the relationship between psychological ownership and turnover intention. Additionally, work relationship closeness moderates the relationship between territoriality and turnover intention such that the negative relationship is stronger when employees experience a higher level of work relationship closeness. Theoretical and practical implications are discussed.展开更多
The advantages of sodium-ion batteries(SIBs)for large-scale energy storage are well known.Among possible anode materials,hard carbon(HC)stands out as the most viable commercial option because of its superior performan...The advantages of sodium-ion batteries(SIBs)for large-scale energy storage are well known.Among possible anode materials,hard carbon(HC)stands out as the most viable commercial option because of its superior performance.However,there is still disagreement regarding the sodium storage mechanism in the low-voltage plateau region of HC anodes,and the structure-performance relationship between its complex multiscale micro/nanostructure and electrochemical behavior remains unclear.This paper summarizes current research progress and the major problems in understanding HC’s microstructure and sodium storage mechanism,and the relationship between them.Findings about a universal sodium storage mechanism in HC,including predictions about micropore-capacity relationships,and the opportunities and challenges for using HC anodes in commercial SIBs are presented.展开更多
Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiv...Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.展开更多
Two sets are close if their symmetric difference is a sparse set. It is shown that NP-hard sets are not C=P-close unless NP C=C=P. This improves the previous result and has implication in quantum compulation.
Robustness of the network topology is a key aspect in the design of computer networks. Residual closeness is a new graph-theoretic concept defined as a measure of network robustness due to the failure of individual ve...Robustness of the network topology is a key aspect in the design of computer networks. Residual closeness is a new graph-theoretic concept defined as a measure of network robustness due to the failure of individual vertices. We identify those graphs with maximum residual closeness among connected graphs with fixed connectivity, edge connectivity and bipartiteness, respectively.展开更多
Hard carbon(HC)is considered the most promising anode material for sodium-ion batteries(SIBs)due to its high costeffectiveness and outstanding overall performance.However,the amorphous and intricate microstructure of ...Hard carbon(HC)is considered the most promising anode material for sodium-ion batteries(SIBs)due to its high costeffectiveness and outstanding overall performance.However,the amorphous and intricate microstructure of HC poses significant challenges in elucidating the structure-performance relationship,which has led to persistent misinterpretations regarding the intrinsic characteristics of closed pores.An irrational construction methodology of closed pores inevitably results in diminished plateau capacity,which severely restricts the practical application of HC in high-energy-density scenarios.This review provides a systematic exposition of the conceptual framework and origination mechanisms of closed pores,offering critical insights into their structural characteristics and formation pathways.Subsequently,by correlating lattice parameters with defect configurations,the structure-performance relationships governing desolvation kinetics and sodium storage behavior are rigorously established.Furthermore,pioneering advancements in structural engineering are critically synthesized to establish fundamental design principles for the rational modulation of closed pores in HC.It is imperative to emphasize that adopting a molecular-level perspective,coupled with a synergistic kinetic/thermodynamic approach,is critical for understanding and controlling the transformation process from open pores to closed pores.These innovative perspectives are strategically designed to accelerate the commercialization of HC,thereby catalyzing the sustainable and high-efficiency development of SIBs.展开更多
In order to improve the efficient and high-value recycling utilization rate of waste red bricks from construction waste,this study crushed and ground the waste red bricks to produce recycled brick powder(RBP)with diff...In order to improve the efficient and high-value recycling utilization rate of waste red bricks from construction waste,this study crushed and ground the waste red bricks to produce recycled brick powder(RBP)with different fineness,used the Andreasen model to explore the influence of RBP on the compact filling effect of cementitious material system based on the basic characteristics of RBP.The influence of grinding time(10,20,30 min)and content(0%,5%,10%,15%,20%)of RBP on the macroscopic mechanical properties of cementitious materials was investigated.We analyzed the significant impact of RBP particle characteristics on the compressive strength of the specimen with the aid of grey entropy theory,and revealed the influence mechanism of RBP on the microstructure of cementitious materials by scanning electron microscope(SEM)and nuclear magnetic resonance(NMR).The results show that the fineness of RBP after grinding is smaller than that of cement.The fineness of recycled brick powder increases gradually with the extension of grinding time,which is manifested as the increase of<3μm particles and the decrease of>18μm particles.Compared with the unitary cement cementitious material system,the particle gradation of the RBP-cement binary cementitious material system is closer to the closest packing state.With the increase of RBP content and grinding time,the compactness of the binary cementitious system gradually decreases,indicating that the incorporation of RBP reduces the mechanical strength of the specimen.The results of grey entropy show that the specific surface area D(0.1)and<45μm particles are the significant factors affecting the mechanical properties of cementitious materials mixed with RBP.RBP mainly affects the macroscopic properties of cementitious materials by affecting the internal compactness,the number of hydration products and the pore structure.The results of SEM show that when the RBP content is less than 15%,the content of C-S-H in cement paste increase,and the content of Ca(OH)2 decreases,and the content of C-S-H decreases and the content of Ca(OH)2 increases when the RBP content is more than 15%.The NMR results show that with the extension of grinding time,the pore size of micropore increases gradually,that of middle-small pores decreases gradually,and that of large pores remains unchanged.With the increase of RBP content,the micropores first decrease and then increase,and the middle-small pores and large pores gradually decrease.In summary,the compactness of cementitious material system can be improved by adjusting the fineness of RBP.Considering the performance of cementitious materials and the utilization rate of RBP,it is recommended that the grinding time of RBP is 20 min and the content is 10%-15%.展开更多
Loess is susceptible to loading effects such as significant changes in strength and volume variation caused by loading and wetting.In this study,considering the different connection states of pore water and gas in loe...Loess is susceptible to loading effects such as significant changes in strength and volume variation caused by loading and wetting.In this study,considering the different connection states of pore water and gas in loess fabric,the gas phase closure case is incorporated into a unified form of the generalized effective stress framework,introducing a damage parameter considering the effects of closed pore gas.The loading effects of unsaturated loess under wide variations in saturation are described in a unified way,and the model performance is verified by corresponding stress and hydraulic path tests.The results indicated that the collapse response involves the initial void ratio of loess,and the coupled outwards motion of the loading-collapse(LC)yield surface under loading enhances its structural strength.Suction-enhanced yield stress requires a greater"tensile stress"to counteract its structural stability.The nucleation of bubbles at high saturation causes a decrease in yield stress.The loading effect exhibits a smaller collapse behavior when the influence of closed gas is considered,whereas the suction path does not cross the LC in the stress space under hydraulic action for the same parameters,which amplifies the influence of closed gas on loess deformation.展开更多
文摘Objectives:Suicidal ideation(SI)among university students is a growing concern,influenced by anxiety,depression,and bullying.However,family closeness and peer support may act as protective factors,reducing the risk of SI.Therefore,this study aims to investigate the key factors influencing SI among university students,focusing on the effects of anxiety,depression,and bullying,along with the roles of family closeness and peer support.The research also explores the interactions and mechanisms between these variables.Methods:A sample of 318 university students was surveyed,evaluating six main factors:anxiety,depression,bullying,family closeness,peer support,and SI.Using the Structural Equation Modeling(SEM)and Artificial Neural Networks(ANN)approach,both compensatory and non-compensatory relationships were examined.Results:Anxiety,depression,and bullying significantly contribute to SI,with depression mediating the link between anxiety,bullying,and SI.Additionally,family closeness moderates the effects of anxiety and bullying on SI,while peer supportmoderates the effects of depression and bullying.Themultilayer perceptron analysis identifies peer support as the most influential predictor,followed by bullying,family closeness,depression,and anxiety.Conclusion:The study identifies anxiety,depression,and bullying as key factors influencing suicidal ideation(SI)among university students.Family closeness and peer support act as protective factors,moderating the effects of these variables on SI.
基金The National Natural Science Foundation of China(No50608017,50538020)
文摘Based on the theory of pattern recognition, the concept of closeness degree between fuzzy sets is brought into the condition assessment of long span bridges. Using the fuzzy analytic hierarchy process （FAHP）, a mathematical model of a multi-objective assessment of a long span suspension bridge is set up. An example is given to show the procedure in the synthetical condition assessment of the Runyang Suspension Bridge, which includes the hierarchical division, the definition of factor weights and fuzzy membership functions, and the calculation of closeness degrees, etc. The assessment combines both the data from the health monitoring system and the manual tests. The classification of evaluation items as well as the calculation of deterministic and nondeterministic items is presented. Compared with the traditional method of point rating, this method can better describe the discreteness of monitoring data and the fuzziness in the condition assessment.
文摘The main activities in project portfolio allocation management are selecting the right project components given a strategy. It is crucial to establish a scientific system of evaluation indexes to guarantee the closeness between strategy and project portfolio allocation optimally. With organizations growing in sizes, the functions and objectives of project components are becoming more and more different. It is necessary to set evaluation indexes of the degree of closeness from the perspectives of financial, market share, social effects, and so on according to the strategy-oriented process of project portfolio allocation. This paper proposes a project portfolio allocation process under strategic orientation and evaluation indexes of the degree of closeness between strategy and project portfolio allocation. This will help projects managers make portfolio allocation decisions.
文摘Is one knowing about their parents’social lives associated with how close they are to them?An obvious answer might be yes.We first found that in a sample of Chinese students,they are more aware of the number of friends their mother has tham the friends their dads have.We then found that,for girls,knowing their mom and dad's friends predicts closeness with dad.Closeness to mother is not associated with knowledge of either parents’social network.For boys,however,knowing mothers’friends(but not the father’s friends)predicts their closeness to the father.As with girls,knowing either parent’s network is not associated with maternal closeness.This research implies that there are different ways closeness emerges between mothers and fathers and their children.
基金supported by the National Natural Science Foundation of China,Nos.82271397(to MG),82001293(to MG),82171355(to RX),81971295(to RX),and 81671189(to RX)。
文摘Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.
基金This work has been supported by National Science and Technology Major Project of China （NMP） （2010ZX03004-002 and 2012ZX03003-003）, the Strategic Pilot Project of Chinese Academy of Sciences （XDA06010302）, and the National Natural Science Foundation of China （Grant No. 60972083）.
文摘Network virtualization aims to provide a way to overcome ossification of the Internet. However, making efficient use of substrate resources requires effective techniques for embedding virtual networks： mapping virtual nodes and virtual edges onto substrate networks. Previous research has presented several heuristic algorithms, which fail to consider that the attributes of the substrate topology and virtual net- works affect the embedding process. In this paper, for the first time, we introduce complex network centrality analysis into the virtual network embedding, and propose virtual network embedding algorithms based on closeness centrality. Due to considering of the attributes of nodes and edges in the topology, our studies are more reasonable than existing work. In addition, with the guidance of topology quantitative evalua- tion, the proposed network embedding approach largely improves the network utilization efficiency and decreases the embedding complexity. We also investigate our algorithms on real network topologies （e.g., AT＆T, DFN） and random network topologies. Experimental results demonstrate the usability and capability of the proposed approach.
基金the National Natural Science Foundation of China(No.21978164,22078189 and 22105120)the Outstanding Youth Science Fund of Shaanxi Province(No.2021JC-046)and the Special Support Program for high level talents of Shaanxi Province+3 种基金the Innovation Support Program of Shaanxi Province(2021JZY-001)the Key Research and Development Program of Shaanxi Province(No.2020GY-243)the Special Research Fund of Education Department of Shaanxi(No.20JK0535)the National High-end Foreign Expert Project(No.GDW20186100428).
文摘Pore structure engineering has been acknowledged as suitable approach to creating active sites and en-hancing ion transport capabilities of hard carbon anodes.However,conventional porous carbon materials exhibit high BET and surface defects.Additionally,the sodium storage mechanism predominantly occurs in the slope region.This contradicts practical application requirements because the capacity of the plateau region is crucial for determining the actual capacity of batteries.In our work,we prepared a novel“core-shell”carbon framework(CNA1200).Introducingclosedporesand carboxylgroupsinto coal-basedcarbon materials to enhance its sodium storage performance.The closed pore structure dominates in the“core”structure,which is attributed to the timely removal of sodium hydroxide(NaOH)to prevent further for-mation of active carbon structure.The presence of closed pores is beneficial for increasing sodium ion storage in the low-voltage plateau region.And the“shell”structure originates from coal tar pitch,it not only uniformly connects hard carbon particles together to improve cycling stability,but is also rich in carboxyl groups to enhance the reversible sodium storage performance in slope region.CNA1200 has ex-cellent electrochemical performance,it exhibits a specific capacity of 335.2 mAh g^(−1)at a current density of 20 mA g^(−1)with ICE=51.53%.In addition,CNA1200 has outstanding cycling stability with a capac-ity retention of 91.8%even when cycling over 200 times.When CNA1200 is used as anode paired with Na_(3)V_(2)(PO_(4))_(3)cathode,it demonstrates a capacity of 109.54 mAh g^(−1)at 0.1 C and capacity retention of 94.64%at 0.5 C.This work provides valuable methods for regulating the structure of sodium-ion battery(SIBs)anode and enhances the potential for commercialization.
文摘Importance:Parent-infant closeness and active parent participation in neonatal care are important for parent and infant health.Objective:To give an overview of current neonatal settings and gain an in-depth understanding of facilitators and barriers to parent-infant closeness,zero-separation,in 19 countries.Methods:Neonatal intensive care unit(NICU)professionals,representing 45 NICUs from a range of geographic regions in Europe and Canada,were purposefully selected and interviewed June–December 2018.Thematic analysis was conducted to identify,analyze and report patterns(themes)for parent-infant closeness across the entire series of interviews.Results:Parent-infant separation during infant and/or maternity care is very common(42/45 units,93%),despite the implementation of family integrated care(FICare)practices,including parent participation in medical rounds(17/45,38%),structured education sessions for parents(16/45,36%)and structured training for healthcare professionals(22/45,49%).NICU professionals encountered four main themes with facilitators and barriers for parent-infant closeness on and between the hospital,unit,staff,and family level:Culture(jointly held characteristics,values,thinking and behaviors about parental presence and participation in the unit),Collaboration(the act of working together between and within different levels),Capacities(resources and policies),andCoaching(education to acquire and transfer knowledge and skills).Interpretation:Implementing parent-infant closeness in the NICU is still challenging for healthcare professionals.Further optimization in neonatal care towards zero-separation and parent-infant closeness can be achieved by enforcing the’’four Cs for Closeness’:Culture,Collaboration,Capacities,andCoaching.
基金supported by the National Natural Science Foundation of China(42167068,22269020)the Gansu Province Higher Education Industry Support Plan Project(2023CYZC-68)the Central Guidance for Local Science and Technology Development Funds Project(YDZX20216200001007)。
文摘Rationally regulating the porosity of hard carbon(HC),especially the closed pores matching the low potential plateau and the ultra-microporous structure suitable for Na+embedding,has been shown to be the key to improving the sodium storage performance and initial coulombic efficiency(ICE).However,the preparation of such HC materials with specific pore structures still faces great challenges.Herein,a simple pre-oxidation strategy is employed to construct abundant closed ultra-microporous structures in soy protein powder-derived HC material,achieving a significant improvement in its ICE and platform capacity.The pre-oxidation process promotes the cross-linking degree of the soy protein,thereby hindering the directional growth of graphite domains during the carbonization process.The optimized HC exhibits ultra-high platform capacity(329 mAh g^(-1))and considerable energy density(148.5 Wh kg^(-1)).Based on the ex-situ Raman and X-ray photoelectron spectroscopy characterization results,the excellent sodium storage capacity of the HC material is attributed to the synergistic effect of adsorption-intercalation/filling.The presented work provides novel insights into the synthesis of other biomass-derived HC materials with abundant closed ultra-micro pores.
基金This research is supported by a grant from the Chinese National Natural Science Foundation （project code： 71372160）.
文摘Drawing on a tripartite perspective on attitudes, this study examines the influence of psychological ownership and territoriality on turnover intention, as well as the moderating role of work relationship closeness on the relationship between territoriality and turnover intention. Analyses of longitudinal data collected from 341 employees in three Chinese automobile manufacturing companies demonstrate that employees＇ psychological ownership is negatively related to their turnover intention. As well, territoriality is negatively related to turnover intention and mediates the relationship between psychological ownership and turnover intention. Additionally, work relationship closeness moderates the relationship between territoriality and turnover intention such that the negative relationship is stronger when employees experience a higher level of work relationship closeness. Theoretical and practical implications are discussed.
文摘The advantages of sodium-ion batteries(SIBs)for large-scale energy storage are well known.Among possible anode materials,hard carbon(HC)stands out as the most viable commercial option because of its superior performance.However,there is still disagreement regarding the sodium storage mechanism in the low-voltage plateau region of HC anodes,and the structure-performance relationship between its complex multiscale micro/nanostructure and electrochemical behavior remains unclear.This paper summarizes current research progress and the major problems in understanding HC’s microstructure and sodium storage mechanism,and the relationship between them.Findings about a universal sodium storage mechanism in HC,including predictions about micropore-capacity relationships,and the opportunities and challenges for using HC anodes in commercial SIBs are presented.
文摘A survey of recent progress on the multiplicity and stability problems for closed characteristics on compact convex hypersurfaces in R^(2n) is given.
文摘Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.
文摘Two sets are close if their symmetric difference is a sparse set. It is shown that NP-hard sets are not C=P-close unless NP C=C=P. This improves the previous result and has implication in quantum compulation.
基金supported by the National Natural Science Foundation of China(No.12071158).
文摘Robustness of the network topology is a key aspect in the design of computer networks. Residual closeness is a new graph-theoretic concept defined as a measure of network robustness due to the failure of individual vertices. We identify those graphs with maximum residual closeness among connected graphs with fixed connectivity, edge connectivity and bipartiteness, respectively.
基金supported by the National Natural Science Foundation of China(22379165,U21A20284)Natural Science Foundation of Hunan Province(2023JJ40704).
文摘Hard carbon(HC)is considered the most promising anode material for sodium-ion batteries(SIBs)due to its high costeffectiveness and outstanding overall performance.However,the amorphous and intricate microstructure of HC poses significant challenges in elucidating the structure-performance relationship,which has led to persistent misinterpretations regarding the intrinsic characteristics of closed pores.An irrational construction methodology of closed pores inevitably results in diminished plateau capacity,which severely restricts the practical application of HC in high-energy-density scenarios.This review provides a systematic exposition of the conceptual framework and origination mechanisms of closed pores,offering critical insights into their structural characteristics and formation pathways.Subsequently,by correlating lattice parameters with defect configurations,the structure-performance relationships governing desolvation kinetics and sodium storage behavior are rigorously established.Furthermore,pioneering advancements in structural engineering are critically synthesized to establish fundamental design principles for the rational modulation of closed pores in HC.It is imperative to emphasize that adopting a molecular-level perspective,coupled with a synergistic kinetic/thermodynamic approach,is critical for understanding and controlling the transformation process from open pores to closed pores.These innovative perspectives are strategically designed to accelerate the commercialization of HC,thereby catalyzing the sustainable and high-efficiency development of SIBs.
基金the Yunnan Engineering Research Center Innovation Ability Construction and Enhancement Projects[2023-XMDJ-00617107]Natural Science Foundation of Yunnan Province[202401AS070646]Natural Science Foundation of Jiangxi Provincial[20232BAB214038].
文摘Despite progress in suppressing polysulfide shuttling,this challenge persists in lithium-sulfur battery commercialization.While existing strategies emphasize polysulfide adsorption and catalytic conversion,the critical role of diffusion kinetics in conversion–deposition processes remains underexplored.We design an MXene-based array architecture integrating 2D structural advantages and strong polysulfide affinity to regulate diffusion pathways.Combined experimental and multiscale computational studies reveal diffusion-mediated conversion-deposition dynamics.The sodium alginate-constructed MXene array enables three synergistic mechanisms:(1)Enhanced ion/electron delocalization reduces diffusion barriers,(2)Continuous ion transport channels facilitate charge transfer,and(3)Exposed polar surfaces promote polysulfide aggregation/conversion.Synchrotron X-ray tomography coupled with comprehensive electrochemical analyses reveals distinct mechanistic differences between conversion and deposition processes arising from diffusion heterogeneity.In situ characterization techniques combined with DFT simulation calculations demonstrate that diffusion kinetics exerts differential regulatory effects on these coupled electrochemical processes,exhibiting particular sensitivity toward the deposition mechanism.This work provides fundamental insights that reshape our understanding of diffusion-mediated phase transformation in complex multi-step electrochemical systems,offering new perspectives for advanced electrode architecture design in next-generation energy storage technologies.
基金Funded by National Natural Science Foundation of China(No.52108219)Lanzhou University of Technology Hongliu Outstanding Young Talent Program,China(No.062407)The High Quality of Green Machine-made Aggregate and the Evolution Mechanism of Concrete Life Cycle Performance in the Harsh Environment of Northwest China(No.U21A20150)。
文摘In order to improve the efficient and high-value recycling utilization rate of waste red bricks from construction waste,this study crushed and ground the waste red bricks to produce recycled brick powder(RBP)with different fineness,used the Andreasen model to explore the influence of RBP on the compact filling effect of cementitious material system based on the basic characteristics of RBP.The influence of grinding time(10,20,30 min)and content(0%,5%,10%,15%,20%)of RBP on the macroscopic mechanical properties of cementitious materials was investigated.We analyzed the significant impact of RBP particle characteristics on the compressive strength of the specimen with the aid of grey entropy theory,and revealed the influence mechanism of RBP on the microstructure of cementitious materials by scanning electron microscope(SEM)and nuclear magnetic resonance(NMR).The results show that the fineness of RBP after grinding is smaller than that of cement.The fineness of recycled brick powder increases gradually with the extension of grinding time,which is manifested as the increase of<3μm particles and the decrease of>18μm particles.Compared with the unitary cement cementitious material system,the particle gradation of the RBP-cement binary cementitious material system is closer to the closest packing state.With the increase of RBP content and grinding time,the compactness of the binary cementitious system gradually decreases,indicating that the incorporation of RBP reduces the mechanical strength of the specimen.The results of grey entropy show that the specific surface area D(0.1)and<45μm particles are the significant factors affecting the mechanical properties of cementitious materials mixed with RBP.RBP mainly affects the macroscopic properties of cementitious materials by affecting the internal compactness,the number of hydration products and the pore structure.The results of SEM show that when the RBP content is less than 15%,the content of C-S-H in cement paste increase,and the content of Ca(OH)2 decreases,and the content of C-S-H decreases and the content of Ca(OH)2 increases when the RBP content is more than 15%.The NMR results show that with the extension of grinding time,the pore size of micropore increases gradually,that of middle-small pores decreases gradually,and that of large pores remains unchanged.With the increase of RBP content,the micropores first decrease and then increase,and the middle-small pores and large pores gradually decrease.In summary,the compactness of cementitious material system can be improved by adjusting the fineness of RBP.Considering the performance of cementitious materials and the utilization rate of RBP,it is recommended that the grinding time of RBP is 20 min and the content is 10%-15%.
基金funded by the National Natural Science Foundation of China (Grant Nos.42230712,42472357)the China Postdoctoral Science Foundation (Grant No.2023MD734211).
文摘Loess is susceptible to loading effects such as significant changes in strength and volume variation caused by loading and wetting.In this study,considering the different connection states of pore water and gas in loess fabric,the gas phase closure case is incorporated into a unified form of the generalized effective stress framework,introducing a damage parameter considering the effects of closed pore gas.The loading effects of unsaturated loess under wide variations in saturation are described in a unified way,and the model performance is verified by corresponding stress and hydraulic path tests.The results indicated that the collapse response involves the initial void ratio of loess,and the coupled outwards motion of the loading-collapse(LC)yield surface under loading enhances its structural strength.Suction-enhanced yield stress requires a greater"tensile stress"to counteract its structural stability.The nucleation of bubbles at high saturation causes a decrease in yield stress.The loading effect exhibits a smaller collapse behavior when the influence of closed gas is considered,whereas the suction path does not cross the LC in the stress space under hydraulic action for the same parameters,which amplifies the influence of closed gas on loess deformation.
