The main method of casting coal spontaneous combustion is prediction of index gases, with carbon monoxide(CO) commonly used as an index gas. However, coal spontaneous combustion is not the sole source of CO evolution;...The main method of casting coal spontaneous combustion is prediction of index gases, with carbon monoxide(CO) commonly used as an index gas. However, coal spontaneous combustion is not the sole source of CO evolution; primal CO is generated through coalification, which can lead to forecasting mistakes. Through theoretical analysis, primal CO generation and emission from coal seams was determined.In this study, six coal samples were analyzed under six different experimental conditions. The results demonstrated the change in coal seam primal gas and concentration as functions of time, different coal samples, occurrence, various gas types and composition concentration, which are in agreement with the previous study on primal CO generation. Air charging impacts on primal gas emission. Analysis of the experimental data with SPSS demonstrates that the relationship between primal CO concentration and time shows a power exponent distribution.展开更多
Regular expressions are widely used within and even outside of computer science due to their expressiveness and flexibility.However, regular expressions have a quite compact and rather tolerant syntax that makes them ...Regular expressions are widely used within and even outside of computer science due to their expressiveness and flexibility.However, regular expressions have a quite compact and rather tolerant syntax that makes them hard to understand, hard to compose,and error-prone. Faulty regular expressions may cause failures of the applications that use them. Therefore, ensuring the correctness of regular expressions is a vital prerequisite for their use in practical applications. The importance and necessity of ensuring correct definitions of regular expressions have attracted extensive attention from researchers and practitioners, especially in recent years. In this study, we provide a review of the recent works for ensuring the correct usage of regular expressions. We classify those works into different categories, including the empirical study, test string generation, automatic synthesis and learning, static checking and verification,visual representation and explanation, and repairing. For each category, we review the main results, compare different approaches, and discuss their advantages and disadvantages. We also discuss some potential future research directions.展开更多
As an inverse problem aimed to find the equivalence relationship between the free surface pressure distribution and boby motion, we choose a simple wave generation problem in a two-dimensional wave tank for analysis, ...As an inverse problem aimed to find the equivalence relationship between the free surface pressure distribution and boby motion, we choose a simple wave generation problem in a two-dimensional wave tank for analysis, that is, we attempt to find a proper free surface pressure distribution which, instead of the wave-making plate, can generate the same fluid field in the wave tank as if the plate would exist? Regularization approach is adopted to tackle this ill-posed inverse problem. The present study manifests that the equivalence relationship could be practically established by solving the corresponding inverse problem although more efforts should be paid for bodies with arbitrary shape.展开更多
基金provided by the National Natural Science Foundation of China(No.U1261214)
文摘The main method of casting coal spontaneous combustion is prediction of index gases, with carbon monoxide(CO) commonly used as an index gas. However, coal spontaneous combustion is not the sole source of CO evolution; primal CO is generated through coalification, which can lead to forecasting mistakes. Through theoretical analysis, primal CO generation and emission from coal seams was determined.In this study, six coal samples were analyzed under six different experimental conditions. The results demonstrated the change in coal seam primal gas and concentration as functions of time, different coal samples, occurrence, various gas types and composition concentration, which are in agreement with the previous study on primal CO generation. Air charging impacts on primal gas emission. Analysis of the experimental data with SPSS demonstrates that the relationship between primal CO concentration and time shows a power exponent distribution.
基金by National Natural Science Foundation of China(Nos.61872339,61502184 and 61925203).
文摘Regular expressions are widely used within and even outside of computer science due to their expressiveness and flexibility.However, regular expressions have a quite compact and rather tolerant syntax that makes them hard to understand, hard to compose,and error-prone. Faulty regular expressions may cause failures of the applications that use them. Therefore, ensuring the correctness of regular expressions is a vital prerequisite for their use in practical applications. The importance and necessity of ensuring correct definitions of regular expressions have attracted extensive attention from researchers and practitioners, especially in recent years. In this study, we provide a review of the recent works for ensuring the correct usage of regular expressions. We classify those works into different categories, including the empirical study, test string generation, automatic synthesis and learning, static checking and verification,visual representation and explanation, and repairing. For each category, we review the main results, compare different approaches, and discuss their advantages and disadvantages. We also discuss some potential future research directions.
文摘As an inverse problem aimed to find the equivalence relationship between the free surface pressure distribution and boby motion, we choose a simple wave generation problem in a two-dimensional wave tank for analysis, that is, we attempt to find a proper free surface pressure distribution which, instead of the wave-making plate, can generate the same fluid field in the wave tank as if the plate would exist? Regularization approach is adopted to tackle this ill-posed inverse problem. The present study manifests that the equivalence relationship could be practically established by solving the corresponding inverse problem although more efforts should be paid for bodies with arbitrary shape.
