The banking industry plays an important role in China's financial market, and the systemic risk of the banking industry has astrong risk spillover effect. This paper measures the systemic risk spillover effect of ...The banking industry plays an important role in China's financial market, and the systemic risk of the banking industry has astrong risk spillover effect. This paper measures the systemic risk spillover effect of Chinese listed commercial banks byconstructing the quantile CoVaR model. The study concluded that when an extreme risk event occurs, the overall risk spillovereffect of a single bank on the banking system is greater than the risk spillover effect of the banking system on a single bank, thevalue of VaR is smaller than the actual risk value when measuring the risk value of commercial banks and the CoVaR model ismore accurate in measuring systemic risk.展开更多
The aquatic plant Nymphaea,a model genus of the early flowering plant lineage Nymphaeales and family Nymphaeaceae,has been extensively studied.However,the availability of chloroplast genome data for this genus is inco...The aquatic plant Nymphaea,a model genus of the early flowering plant lineage Nymphaeales and family Nymphaeaceae,has been extensively studied.However,the availability of chloroplast genome data for this genus is incomplete,and phylogenetic relationships within the order Nymphaeales remain controversial.In this study,12 chloroplast genomes of Nymphaea were assembled and analyzed for the first time.These genomes were 158,290-160,042 bp in size and contained 113 non-repeat genes,including 79 protein-coding genes,30 tRNA genes,and four rRNA genes.We also report on codon usage,RNA editing sites,microsatellite structures,and new repetitive sequences in this genus.Comparative genomics revealed that expansion and contraction of IR regions can lead to changes in the gene numbers.Additionally,it was observed that the highly variable regions of the chloroplast genome were mainly located in intergenic regions.Furthermore,the phylogenetic tree showed the order Nymphaeales was divided into three families,and the genus Nymphaea can be divided into five(or three)subgenera,with the subgenus Nymphaea being the oldest.The divergence times of nymphaealean taxa were analyzed,with origins of the order Nymphaeales and family Nymphaeaceae being about 194 and 131 million years,respectively.The results of the phylo-genetic analysis and estimated divergence times will be useful for future evolutionary studies of basal angiosperm lineages.展开更多
A micro fluidized bed reactor was used to study the self-sustaining catalytic combustion of carbon monoxide(CO).The Cu_(1−x)Ce_(x)O_(y) catalyst,as well as the pure CuO and CeO_(2),are used to investigate the contribu...A micro fluidized bed reactor was used to study the self-sustaining catalytic combustion of carbon monoxide(CO).The Cu_(1−x)Ce_(x)O_(y) catalyst,as well as the pure CuO and CeO_(2),are used to investigate the contributing mechanism of different active sites including dispersed CuO and Cu–Ce solid solutions.The ignition temperature(Ti)of CO over these catalysts at a flow rate of 2000 mL/min followed the order:74℃(Cu_(0.5)Ce_(0.5)O_(y))<75℃(Cu_(0.25)Ce_(0.75)O_(y))<84℃(Cu_(0.75)Ce_(0.25)O_(y))<105℃(CuO)<500℃(CeO_(2)).Furthermore,the lean combustion limits(equivalence ratioϕ)over these catalysts under the flow rates of 750–3000 mL/min(through fixed,bubbling,and fluidized bed)were also measured,which are Cu_(0.5)Ce_(0.5)O_(y)<Cu_(0.25)Ce_(0.75)Oy<Cu_(0.75)Ce_(0.25)O_(y)<CuO<CeO_(2).The fluidized bed was simulated using the Eulerian two-fluid model(TFM)coupled with a diffusion/kinetic-limited reaction model to evaluate the influence of operation conditions on the self-sustained combustion of CO.The predicted maximum temperature agreed with the experimental measurements,demonstrating the validity of the kinetic model and simulation parameters.The results of catalytic combustion with increasing CO concentrations suggest that the catalytic combustion reaction could co-exist with the flamed combustion.When a high concentration of CO is used,a blue-purple flame caused by CO combustion appears in the upper part of the fluidized bed,indicating that the range of CO-containing exhaust gas purification could be expanded to a larger range using the fluidized-bed catalytic combustion technique.展开更多
With the advent of the“Big Data Era”,improving data storage density and computation speed has become more and more urgent due to the rapid growth in different types of data.Flash memory with a floating gate(FG)struc...With the advent of the“Big Data Era”,improving data storage density and computation speed has become more and more urgent due to the rapid growth in different types of data.Flash memory with a floating gate(FG)structure is attracting great attention owing to its advantages of miniaturization,low power consumption and reli-able data storage,which is very effective in solving the problems of large data capacity and high integration density.Meanwhile,the FG memory with charge storage principle can simulate synaptic plasticity perfectly,breaking the traditional von Neumann computing ar-chitecture and can be used as an artificial synapse for neuromorphic computations inspired by the human brain.Among many candidate materials for manufacturing devices,van der Waals(vdW)materials have attracted widespread attention due to their atomic thickness,high mobility,and sustainable miniaturization properties.Owing to the arbitrary stacking ability,vdW heterostructure combines rich physics and potential 3D integration,opening up various possibilities for new functional integrated devices with low power consumption and flexible applications.This paper provides a comprehensive review of memory devices based on vdW materials with FG structure,including the working principles and typical structures of FG structure devices,with a focus on the introduction of various highperformance FG memories and their versatile applications in neuro-morphic computing.Finally,the challenges of neuromorphic devices based on FG structures are also discussed.This review will shed light on the design and fabrication of vdW material-based memory devices with FG engineering,helping to promote the development of practical and promising neuromorphic computing.展开更多
文摘The banking industry plays an important role in China's financial market, and the systemic risk of the banking industry has astrong risk spillover effect. This paper measures the systemic risk spillover effect of Chinese listed commercial banks byconstructing the quantile CoVaR model. The study concluded that when an extreme risk event occurs, the overall risk spillovereffect of a single bank on the banking system is greater than the risk spillover effect of the banking system on a single bank, thevalue of VaR is smaller than the actual risk value when measuring the risk value of commercial banks and the CoVaR model ismore accurate in measuring systemic risk.
基金supported by the National Natural Science Foundation of China(No.32370244)the Taishan Scholar Project(No.tsqn202306214)+1 种基金the Shandong Province Natural Science Foundation of China(No.ZR2023MC157)the State Key Laboratory of Pal-aeobiology and Stratigraphy(No.223123).
文摘The aquatic plant Nymphaea,a model genus of the early flowering plant lineage Nymphaeales and family Nymphaeaceae,has been extensively studied.However,the availability of chloroplast genome data for this genus is incomplete,and phylogenetic relationships within the order Nymphaeales remain controversial.In this study,12 chloroplast genomes of Nymphaea were assembled and analyzed for the first time.These genomes were 158,290-160,042 bp in size and contained 113 non-repeat genes,including 79 protein-coding genes,30 tRNA genes,and four rRNA genes.We also report on codon usage,RNA editing sites,microsatellite structures,and new repetitive sequences in this genus.Comparative genomics revealed that expansion and contraction of IR regions can lead to changes in the gene numbers.Additionally,it was observed that the highly variable regions of the chloroplast genome were mainly located in intergenic regions.Furthermore,the phylogenetic tree showed the order Nymphaeales was divided into three families,and the genus Nymphaea can be divided into five(or three)subgenera,with the subgenus Nymphaea being the oldest.The divergence times of nymphaealean taxa were analyzed,with origins of the order Nymphaeales and family Nymphaeaceae being about 194 and 131 million years,respectively.The results of the phylo-genetic analysis and estimated divergence times will be useful for future evolutionary studies of basal angiosperm lineages.
基金support from the National Natural Science Foundation of China(No.52176141).
文摘A micro fluidized bed reactor was used to study the self-sustaining catalytic combustion of carbon monoxide(CO).The Cu_(1−x)Ce_(x)O_(y) catalyst,as well as the pure CuO and CeO_(2),are used to investigate the contributing mechanism of different active sites including dispersed CuO and Cu–Ce solid solutions.The ignition temperature(Ti)of CO over these catalysts at a flow rate of 2000 mL/min followed the order:74℃(Cu_(0.5)Ce_(0.5)O_(y))<75℃(Cu_(0.25)Ce_(0.75)O_(y))<84℃(Cu_(0.75)Ce_(0.25)O_(y))<105℃(CuO)<500℃(CeO_(2)).Furthermore,the lean combustion limits(equivalence ratioϕ)over these catalysts under the flow rates of 750–3000 mL/min(through fixed,bubbling,and fluidized bed)were also measured,which are Cu_(0.5)Ce_(0.5)O_(y)<Cu_(0.25)Ce_(0.75)Oy<Cu_(0.75)Ce_(0.25)O_(y)<CuO<CeO_(2).The fluidized bed was simulated using the Eulerian two-fluid model(TFM)coupled with a diffusion/kinetic-limited reaction model to evaluate the influence of operation conditions on the self-sustained combustion of CO.The predicted maximum temperature agreed with the experimental measurements,demonstrating the validity of the kinetic model and simulation parameters.The results of catalytic combustion with increasing CO concentrations suggest that the catalytic combustion reaction could co-exist with the flamed combustion.When a high concentration of CO is used,a blue-purple flame caused by CO combustion appears in the upper part of the fluidized bed,indicating that the range of CO-containing exhaust gas purification could be expanded to a larger range using the fluidized-bed catalytic combustion technique.
基金supported by Beijing Natural Science Foundation(Grant No.Z210006)the National Key Research and Develop-ment Program of China(Grant No.2022YFA1405600)the National Nat-ural Science Foundation of China(Grant No.12104051).
文摘With the advent of the“Big Data Era”,improving data storage density and computation speed has become more and more urgent due to the rapid growth in different types of data.Flash memory with a floating gate(FG)structure is attracting great attention owing to its advantages of miniaturization,low power consumption and reli-able data storage,which is very effective in solving the problems of large data capacity and high integration density.Meanwhile,the FG memory with charge storage principle can simulate synaptic plasticity perfectly,breaking the traditional von Neumann computing ar-chitecture and can be used as an artificial synapse for neuromorphic computations inspired by the human brain.Among many candidate materials for manufacturing devices,van der Waals(vdW)materials have attracted widespread attention due to their atomic thickness,high mobility,and sustainable miniaturization properties.Owing to the arbitrary stacking ability,vdW heterostructure combines rich physics and potential 3D integration,opening up various possibilities for new functional integrated devices with low power consumption and flexible applications.This paper provides a comprehensive review of memory devices based on vdW materials with FG structure,including the working principles and typical structures of FG structure devices,with a focus on the introduction of various highperformance FG memories and their versatile applications in neuro-morphic computing.Finally,the challenges of neuromorphic devices based on FG structures are also discussed.This review will shed light on the design and fabrication of vdW material-based memory devices with FG engineering,helping to promote the development of practical and promising neuromorphic computing.
