The bimodal Taylor expa nsion method of moments (B-TEMOM) model scheme was developed to simulate the formation and evolution of vehicle exhaust particles. Two independent types of log-normal particle size distribution...The bimodal Taylor expa nsion method of moments (B-TEMOM) model scheme was developed to simulate the formation and evolution of vehicle exhaust particles. Two independent types of log-normal particle size distributions were selected in the B-TEMOM model scheme, comprising large and small particles to represent background (i.e., the surrounding environment) and vehicle exhaust particles, respectively. Concentration distributions of exhaust and background particles derived using this model scheme were verified against results from a moving secti onal method and the bimodal quadrature method of moments, showing excellent agreement. The effects of vehicle tailpipe ex 让 cond 让 ions (e.g., exhaust particle concentrations and velocity), sulfurcontent, and relative humidity on the evoluti on of particles were investigated numerically. Both two-dimensional and three-dimensional numerical simulations showed that tailpipe exit velocity and relative humid让y did not greatly affect the steady-state concentrations or the diameters of particles in urban atmospheres. Although an increase in sulfur content had little effect on the particle concentration, it led to background particles with larger geometric average diameter entering the environment. This coupled CFD-B-TEMOM numerical model provides a simple but accurate and efficient method for studying bimodal aerosol dynamics.展开更多
Local community detection aims to find a cluster of nodes by exploring a small region of the network.Local community detection methods are faster than traditional global community detection methods because their runti...Local community detection aims to find a cluster of nodes by exploring a small region of the network.Local community detection methods are faster than traditional global community detection methods because their runtime does not depend on the size of the entire network. However, most existing methods do not take the higher-order connectivity patterns crucial to the network into consideration. In this paper, we develop a new Local Community Detection method based on network Motif(LCD-Motif) which incorporates the higher-order network information. LCD-Motif adopts the local expansion of a seed set to identify the local community with minimal motif conductance, representing a generalization of the conductance metric for network motifs. In contrast to PageRanklike diffusion methods, LCD-Motif finds the community by seeking a sparse vector in the span of the local spectra,such that the seeds are in its support vector. We evaluate our approach using real-world datasets across various domains and synthetic networks. The experimental results show that LCD-Motif can achieve a higher performance than state-of-the-art methods.展开更多
Recently,the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states named X_(0)(2900)and X_(1)(2900)with unknown parity.Inspired by the report,we consider all the possible f...Recently,the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states named X_(0)(2900)and X_(1)(2900)with unknown parity.Inspired by the report,we consider all the possible fourquark candidates for X(2900),which include the molecular structure,diquark structure,and their coupling in a chiral quark model via the Gaussian expansion method.To identify the genuine resonances,the real-scaling method(stabilization method)was employed.Our results show that five possible resonances,R_(0)(2914)withΓ=42 MeV,R_(1)(2906)withΓ=29 MeV,R_(1)(2912)withΓ=10 McV,R_(J)(2920)withΓ=9 MeV,and R_(J)(2842)withΓ=24 MeV,originate in the csqq system.Compared with experimental data,R_(0)(2914)withΓ=42 MeV may be an optimal X_(0)(2900)candidate.However,none of the resonances have a similar width for X_(1)(2900).Hence,further study is required.展开更多
文摘The bimodal Taylor expa nsion method of moments (B-TEMOM) model scheme was developed to simulate the formation and evolution of vehicle exhaust particles. Two independent types of log-normal particle size distributions were selected in the B-TEMOM model scheme, comprising large and small particles to represent background (i.e., the surrounding environment) and vehicle exhaust particles, respectively. Concentration distributions of exhaust and background particles derived using this model scheme were verified against results from a moving secti onal method and the bimodal quadrature method of moments, showing excellent agreement. The effects of vehicle tailpipe ex 让 cond 让 ions (e.g., exhaust particle concentrations and velocity), sulfurcontent, and relative humidity on the evoluti on of particles were investigated numerically. Both two-dimensional and three-dimensional numerical simulations showed that tailpipe exit velocity and relative humid让y did not greatly affect the steady-state concentrations or the diameters of particles in urban atmospheres. Although an increase in sulfur content had little effect on the particle concentration, it led to background particles with larger geometric average diameter entering the environment. This coupled CFD-B-TEMOM numerical model provides a simple but accurate and efficient method for studying bimodal aerosol dynamics.
基金supported by the National Social Science Foundation of China (No. 16ZDA055)
文摘Local community detection aims to find a cluster of nodes by exploring a small region of the network.Local community detection methods are faster than traditional global community detection methods because their runtime does not depend on the size of the entire network. However, most existing methods do not take the higher-order connectivity patterns crucial to the network into consideration. In this paper, we develop a new Local Community Detection method based on network Motif(LCD-Motif) which incorporates the higher-order network information. LCD-Motif adopts the local expansion of a seed set to identify the local community with minimal motif conductance, representing a generalization of the conductance metric for network motifs. In contrast to PageRanklike diffusion methods, LCD-Motif finds the community by seeking a sparse vector in the span of the local spectra,such that the seeds are in its support vector. We evaluate our approach using real-world datasets across various domains and synthetic networks. The experimental results show that LCD-Motif can achieve a higher performance than state-of-the-art methods.
基金Supported in part by the National Natural Science Foundation of China(11775118,11535005)。
文摘Recently,the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states named X_(0)(2900)and X_(1)(2900)with unknown parity.Inspired by the report,we consider all the possible fourquark candidates for X(2900),which include the molecular structure,diquark structure,and their coupling in a chiral quark model via the Gaussian expansion method.To identify the genuine resonances,the real-scaling method(stabilization method)was employed.Our results show that five possible resonances,R_(0)(2914)withΓ=42 MeV,R_(1)(2906)withΓ=29 MeV,R_(1)(2912)withΓ=10 McV,R_(J)(2920)withΓ=9 MeV,and R_(J)(2842)withΓ=24 MeV,originate in the csqq system.Compared with experimental data,R_(0)(2914)withΓ=42 MeV may be an optimal X_(0)(2900)candidate.However,none of the resonances have a similar width for X_(1)(2900).Hence,further study is required.
