To better study the behavior of confined concrete, this paper presents the basic hypothesis of uhimate equilibrium of confined concrete and the unified yield criteria of confining material. Based on the static equilib...To better study the behavior of confined concrete, this paper presents the basic hypothesis of uhimate equilibrium of confined concrete and the unified yield criteria of confining material. Based on the static equilibrium condition and yield criteria of components, a unified bearing capacity model of confined concrete column is proposed, and a simplified calculating equation of the model is also given. The model captures the character of confined concrete column. Effects of the confinement effect ratio, the lateral confinement ratio, unconfined concrete strength and the properties of confining material on the bearing capacity of confined concrete column are carefully considered. The model may be applicable to the calculation of bearing capacity of steel-confined concrete, concrete filled steel tube and FRP-confined concrete. The predictions of the model agree well with test data.展开更多
The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fue...The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fuel engines. Calculated values by the model for natural gas operation showed good agreement with corresponding experimental values over a broad range of operating conditions.展开更多
A reduced chemical kinetic model （44 species and 72 reactions） for the homogeneous charge compression ignition （HCCI） combustion of n-heptane was optimized to improve its autoignition predictions under different e...A reduced chemical kinetic model （44 species and 72 reactions） for the homogeneous charge compression ignition （HCCI） combustion of n-heptane was optimized to improve its autoignition predictions under different engine operating conditions. The seven kinetic parameters of the optimized model were determined by using the combination of a micro-genetic algorithm optimization methodology and the SENKIN program of CHEMKIN chemical kinetics software package. The optimization was performed within the range of equivalence ratios 0.2-1.2, initial temperature 310- 375 K and initial pressure 0, 1-0.3 MPa, The engine simulations show that the optimized model agrees better with the detailed chemical kinetic model （544 species and 2 446 reactions） than the original model does.展开更多
Layered bismuth sulfide （Bi2S3） has emerged as an important type of Li-storage material due to its high theoretical capacity and intriguing reaction mechanism. The engineering and fabrication of Bi2S3 materials with...Layered bismuth sulfide （Bi2S3） has emerged as an important type of Li-storage material due to its high theoretical capacity and intriguing reaction mechanism. The engineering and fabrication of Bi2S3 materials with large capacity and stable cyclability via a facile approach is essential, but still remains a great challenge. Herein, we employ a one-pot hydrothermal route to fabricate carbon-coated Bi2S3 nanomeshes （Bi2S3/C） as an efficient Li-storage material. The nanomeshes serve as a highly conducting and porous scaffold facilitating electron and ion transport, while the carbon coating layer provides flexible space for efficient reduction of mechanical strain upon electrochemical cycling. Consequently, the fabricated Bi2S3/C exhibits a high and stable capacity delivery in the 0.01-2.5 V region, notably outperforming previously reported Bi2S3 materials. It is able to discharge 472 mA·h·g^-1 at 120 mA.g^-1 over 50 full cycles, and to retain 301 mA·h·g^-1 in the 40th cycle at 600 mA.g^-l, demonstrating the potential of Bi2S3 as electrode materials for rechargeable batteries.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.50538060)the Excellent Young College Teacher Foundation of Anhui Prov-ince(Grant No.2009SQRZ081)
文摘To better study the behavior of confined concrete, this paper presents the basic hypothesis of uhimate equilibrium of confined concrete and the unified yield criteria of confining material. Based on the static equilibrium condition and yield criteria of components, a unified bearing capacity model of confined concrete column is proposed, and a simplified calculating equation of the model is also given. The model captures the character of confined concrete column. Effects of the confinement effect ratio, the lateral confinement ratio, unconfined concrete strength and the properties of confining material on the bearing capacity of confined concrete column are carefully considered. The model may be applicable to the calculation of bearing capacity of steel-confined concrete, concrete filled steel tube and FRP-confined concrete. The predictions of the model agree well with test data.
文摘The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fuel engines. Calculated values by the model for natural gas operation showed good agreement with corresponding experimental values over a broad range of operating conditions.
基金SUPPORTED BY NATIONAL KEY BASIC RESEARCH PLAN ("973" PLAN, NO. 2001CB209202).
文摘A reduced chemical kinetic model （44 species and 72 reactions） for the homogeneous charge compression ignition （HCCI） combustion of n-heptane was optimized to improve its autoignition predictions under different engine operating conditions. The seven kinetic parameters of the optimized model were determined by using the combination of a micro-genetic algorithm optimization methodology and the SENKIN program of CHEMKIN chemical kinetics software package. The optimization was performed within the range of equivalence ratios 0.2-1.2, initial temperature 310- 375 K and initial pressure 0, 1-0.3 MPa, The engine simulations show that the optimized model agrees better with the detailed chemical kinetic model （544 species and 2 446 reactions） than the original model does.
文摘Layered bismuth sulfide （Bi2S3） has emerged as an important type of Li-storage material due to its high theoretical capacity and intriguing reaction mechanism. The engineering and fabrication of Bi2S3 materials with large capacity and stable cyclability via a facile approach is essential, but still remains a great challenge. Herein, we employ a one-pot hydrothermal route to fabricate carbon-coated Bi2S3 nanomeshes （Bi2S3/C） as an efficient Li-storage material. The nanomeshes serve as a highly conducting and porous scaffold facilitating electron and ion transport, while the carbon coating layer provides flexible space for efficient reduction of mechanical strain upon electrochemical cycling. Consequently, the fabricated Bi2S3/C exhibits a high and stable capacity delivery in the 0.01-2.5 V region, notably outperforming previously reported Bi2S3 materials. It is able to discharge 472 mA·h·g^-1 at 120 mA.g^-1 over 50 full cycles, and to retain 301 mA·h·g^-1 in the 40th cycle at 600 mA.g^-l, demonstrating the potential of Bi2S3 as electrode materials for rechargeable batteries.
