The mainstream depth of a return flow can be viewed as an intrinsic depth of horizontal convection. By using a theoretical tube model combined with the application of the Maximum Entropy Production Principle (MaxEPP) ...The mainstream depth of a return flow can be viewed as an intrinsic depth of horizontal convection. By using a theoretical tube model combined with the application of the Maximum Entropy Production Principle (MaxEPP) in thermodynamics, the following statements can be made. Under fixed external forcing, the system chooses a particular depth as the mainstream depth of its return flow, the depth of which not only satisfies the maximum circulation rate and the maximum heat transport, but also satisfies the maximum entropy production rate. A comparison between this intrinsic depth and the container height leads to the definition of a relative partial and full-penetration pattern of the circulation. Moreover, this intrinsic depth is found to vary with the external forcing; the regulation of this variation is related to the Modified Rayleigh number.展开更多
Based on the theory of random process and the characteristic of the functioning of a system component subject to a certain specific probability distribution, emulated the whole process of system production on Iongwall...Based on the theory of random process and the characteristic of the functioning of a system component subject to a certain specific probability distribution, emulated the whole process of system production on Iongwall face was emulated, in which the methods of time pace and computer random emulation were adopted. The paper provides an objective basis for the analysis of a mining Iongwall face and the varied lines of effectiveness, machine stoppage rate and coal flow of components and system, and output etc.lt also offers some theories to improve productivity by discussing the application of the transformation plan and optimization of reasonable coal stock capacity, as well as selection of system equipment and matching optimization.展开更多
The analysis and the design of turbojet engines are of great importance to the improvement of the system performance.Many researchers focus on these topics,and many important and interesting results have been obtained...The analysis and the design of turbojet engines are of great importance to the improvement of the system performance.Many researchers focus on these topics,and many important and interesting results have been obtained.In this paper,the thermodynamic cycle in a turbojet engine is analyzed with the entransy theory and the T-Q diagram.The ideal thermodynamic cycle in which there is no inner irreversibility is analyzed,as well as the influences from some inner irreversible factors,such as the heat transfer process,the change of the component of the working fluid and the viscosity of the working fluid.For the discussed cases,it is shown that larger entransy loss rate always results in larger output power,while smaller entropy generation rate does not always.The corresponding T-Q diagrams are also presented,with which the change tendencies of the entransy loss rate and the output power can be shown very intuitively.It is shown that the entransy theory is applicable for analyzing the inner irreversible thermodynamic cycles discussed in this paper.Compared with the concept of entropy generation,the concept of entransy loss and the corresponding T-Q diagram are more suitable for describing the change of the output power of the analyzed turbojet engine no matter if the inner irreversible factors are considered.展开更多
This paper develops a kind of generalized double-sided moral hazard model of contract choice with Cobb-Douglas technology in a frame of principal-agent theory. The two parties, the principal and the agent, generally h...This paper develops a kind of generalized double-sided moral hazard model of contract choice with Cobb-Douglas technology in a frame of principal-agent theory. The two parties, the principal and the agent, generally have different levels of production efficiency, relative importance factor and are risk-averse or risk-neutral. Using this model, we formally prove that the optimal contract maximizes the output net of the disutility of both the parties and carry out some simulations exercise under two special cases which help explain the double-sided moral hazard issues. By focusing on production efficiency, relative importance factor and risk attitude respectively, this paper analyzes the properties of optimal contracts under three cases.展开更多
基金Supported by the The National Basic Research Program (973 Program) (Nos. 2007CB816004, 2005CB422302)the National Outstanding Youth Natural Science Foundation of China (No. 40725017)
文摘The mainstream depth of a return flow can be viewed as an intrinsic depth of horizontal convection. By using a theoretical tube model combined with the application of the Maximum Entropy Production Principle (MaxEPP) in thermodynamics, the following statements can be made. Under fixed external forcing, the system chooses a particular depth as the mainstream depth of its return flow, the depth of which not only satisfies the maximum circulation rate and the maximum heat transport, but also satisfies the maximum entropy production rate. A comparison between this intrinsic depth and the container height leads to the definition of a relative partial and full-penetration pattern of the circulation. Moreover, this intrinsic depth is found to vary with the external forcing; the regulation of this variation is related to the Modified Rayleigh number.
基金Supported by the Special Topics of Major Scientific and Technological Research Projects Shanxi Province (2006031099-01)Youth Science Funds of Shanxi Province (2006021024)Science and Technology Project of Taiyuan City (07010728)
文摘Based on the theory of random process and the characteristic of the functioning of a system component subject to a certain specific probability distribution, emulated the whole process of system production on Iongwall face was emulated, in which the methods of time pace and computer random emulation were adopted. The paper provides an objective basis for the analysis of a mining Iongwall face and the varied lines of effectiveness, machine stoppage rate and coal flow of components and system, and output etc.lt also offers some theories to improve productivity by discussing the application of the transformation plan and optimization of reasonable coal stock capacity, as well as selection of system equipment and matching optimization.
基金supported by the National Natural Science Foundation of China(Grant Nos.51376101&51356001)
文摘The analysis and the design of turbojet engines are of great importance to the improvement of the system performance.Many researchers focus on these topics,and many important and interesting results have been obtained.In this paper,the thermodynamic cycle in a turbojet engine is analyzed with the entransy theory and the T-Q diagram.The ideal thermodynamic cycle in which there is no inner irreversibility is analyzed,as well as the influences from some inner irreversible factors,such as the heat transfer process,the change of the component of the working fluid and the viscosity of the working fluid.For the discussed cases,it is shown that larger entransy loss rate always results in larger output power,while smaller entropy generation rate does not always.The corresponding T-Q diagrams are also presented,with which the change tendencies of the entransy loss rate and the output power can be shown very intuitively.It is shown that the entransy theory is applicable for analyzing the inner irreversible thermodynamic cycles discussed in this paper.Compared with the concept of entropy generation,the concept of entransy loss and the corresponding T-Q diagram are more suitable for describing the change of the output power of the analyzed turbojet engine no matter if the inner irreversible factors are considered.
文摘This paper develops a kind of generalized double-sided moral hazard model of contract choice with Cobb-Douglas technology in a frame of principal-agent theory. The two parties, the principal and the agent, generally have different levels of production efficiency, relative importance factor and are risk-averse or risk-neutral. Using this model, we formally prove that the optimal contract maximizes the output net of the disutility of both the parties and carry out some simulations exercise under two special cases which help explain the double-sided moral hazard issues. By focusing on production efficiency, relative importance factor and risk attitude respectively, this paper analyzes the properties of optimal contracts under three cases.
