Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical cha...Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical charges on the tunnel blast wave loads and to develop a quantitative calculation method, this study carried out experimental and numerical research. Initially, external explosion experiments were conducted using both 35 kg spherical charges and cylindrical charges with aspect ratio of 4.8 at two different distances from the tunnel entrance. Comparative analysis of the blast wave parameters in the tunnel revealed that the explosive equivalent of the cylindrical charges was significantly higher than that of the spherical charges. To address this, an equivalent coefficient κ based on the spherical charges was proposed for the cylindrical charges. Subsequently, numerical simulations were conducted for the experimental conditions, and the numerical simulation results match the experiments well. Through numerical calculations, the reliability of the equivalent coefficient κ under the experimental conditions was verified, and comparison analysis indicated that the explosion energy of cylindrical charges spreads more radially, resulting in more explosion energy entering the tunnel, which is the fundamental reason for the increase in tunnel blast wave loads. Additionally, analyzing the explosion energy ratio entering the tunnel is an effective method for calculating the equivalent coefficient κ. Finally, through more than one hundred sets of numerical calculation results, the impact of the proportional distance λ and the ratio of charge mass to the tunnel cross-section dimension φ on the equivalence coefficients κ was investigated. An empirical formula for the equivalence coefficient κ was derived through fitting, and the accuracy of the formula was validated through literature experimental results. The research findings of this paper will provide valuable guidance for the calculation of blast wave loads in tunnel.展开更多
To improve the productivity of cluster tools in semiconductor fabrications,on the basis of stating scheduling problems,a try and error-based scheduling algorithm was proposed with residency time constraints and an obj...To improve the productivity of cluster tools in semiconductor fabrications,on the basis of stating scheduling problems,a try and error-based scheduling algorithm was proposed with residency time constraints and an objective of minimizing Makespan for the wafer jobs in cluster tools.Firstly,mathematical formulations of scheduling problems were presented by using assumptions and definitions of a scheduling domain.Resource conflicts were analyzed in the built scheduling model,and policies to solve resource conflicts were built.A scheduling algorithm was developed.Finally,the performances of the proposed algorithm were evaluated and compared with those of other methods by simulations.Experiment results indicate that the proposed algorithm is effective and practical in solving the scheduling problem of the cluster tools.展开更多
文摘Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical charges on the tunnel blast wave loads and to develop a quantitative calculation method, this study carried out experimental and numerical research. Initially, external explosion experiments were conducted using both 35 kg spherical charges and cylindrical charges with aspect ratio of 4.8 at two different distances from the tunnel entrance. Comparative analysis of the blast wave parameters in the tunnel revealed that the explosive equivalent of the cylindrical charges was significantly higher than that of the spherical charges. To address this, an equivalent coefficient κ based on the spherical charges was proposed for the cylindrical charges. Subsequently, numerical simulations were conducted for the experimental conditions, and the numerical simulation results match the experiments well. Through numerical calculations, the reliability of the equivalent coefficient κ under the experimental conditions was verified, and comparison analysis indicated that the explosion energy of cylindrical charges spreads more radially, resulting in more explosion energy entering the tunnel, which is the fundamental reason for the increase in tunnel blast wave loads. Additionally, analyzing the explosion energy ratio entering the tunnel is an effective method for calculating the equivalent coefficient κ. Finally, through more than one hundred sets of numerical calculation results, the impact of the proportional distance λ and the ratio of charge mass to the tunnel cross-section dimension φ on the equivalence coefficients κ was investigated. An empirical formula for the equivalence coefficient κ was derived through fitting, and the accuracy of the formula was validated through literature experimental results. The research findings of this paper will provide valuable guidance for the calculation of blast wave loads in tunnel.
基金Projects(71071115,60574054) supported by the National Natural Science Foundation of China
文摘To improve the productivity of cluster tools in semiconductor fabrications,on the basis of stating scheduling problems,a try and error-based scheduling algorithm was proposed with residency time constraints and an objective of minimizing Makespan for the wafer jobs in cluster tools.Firstly,mathematical formulations of scheduling problems were presented by using assumptions and definitions of a scheduling domain.Resource conflicts were analyzed in the built scheduling model,and policies to solve resource conflicts were built.A scheduling algorithm was developed.Finally,the performances of the proposed algorithm were evaluated and compared with those of other methods by simulations.Experiment results indicate that the proposed algorithm is effective and practical in solving the scheduling problem of the cluster tools.
