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 The concepts of agricultural system entropy Sa proposed in this paper, it defined as: a quotient of standard coal energy minus farm produce energy divided by input standard coal weight (Kilocolorce Kilogram~(1)). The agricultural system entropy of 18 counties situated in densely populated areas of lower reach of Yangtze River in Jiang(?)u province was caculated, results showei that 77% of these counties are positive entropy, positive entropy means that the input energy was in waste state. Energy waste is associated... The concepts of agricultural system entropy Sa proposed in this paper, it defined as: a quotient of standard coal energy minus farm produce energy divided by input standard coal weight (Kilocolorce Kilogram~(1)). The agricultural system entropy of 18 counties situated in densely populated areas of lower reach of Yangtze River in Jiang(?)u province was caculated, results showei that 77% of these counties are positive entropy, positive entropy means that the input energy was in waste state. Energy waste is associated with waste of materials, according to the caculation, 42.9% produce of Yangzhong county chmical fertilizer factory was in waste state, then the necessity of closing down of this factory was disscussed.  本文提出农业系统熵的概念,并计算了江苏省最高人口密度分布区沿江地区18个县的农业系统熵。结果表明77％的县的农业系统熵都是正值,投入能量的2—40％都处于无效耗散态,这是农田生态系能量转换效率低下的表现。能量的浪费伴随物质的浪费,以扬中县农田氮素平衡为例,该县化肥厂产量的42.9％处于无效耗散态。文中对停办该厂作了论证。  Begining with a complete analysis of the relation between the entropy production andthe time derivative of the characteristic functions of closed thermodynamic systems based on thelocal equilibrium postulate,it is clarified that the wellknown thermodynamic chatacters ofnonequlilbrium states , both the nonnegative dissipative intensity and the tendency towards tominimum dissipation state in the linear nonequilibrium region are actually identical with the stateevolution direction respectively on the levels... Begining with a complete analysis of the relation between the entropy production andthe time derivative of the characteristic functions of closed thermodynamic systems based on thelocal equilibrium postulate,it is clarified that the wellknown thermodynamic chatacters ofnonequlilbrium states , both the nonnegative dissipative intensity and the tendency towards tominimum dissipation state in the linear nonequilibrium region are actually identical with the stateevolution direction respectively on the levels of the lst and 2nd order timederivatives of thethermodynamic potentials. A new formalism of the 2nd law of thermodynamics of opennonequilibrium systems is suggested by means of the grand potentials meanwhile its equivalence withthe minimum entropy production principle in the linear nonequilibrium region is also discussed, thearguments formed in this paper can be valid for the systems in external fields.  从分析局域平衡理论框架内封闭热力学系统之熵产生与特性函数变率的关系入手，阐明了非平衡态的热力学特征，即非负耗散强度及非平衡线性区向最小耗散态演化的趋势，实际上是分别体现在热力学势的一阶及二阶变率层次上的状态演化方向。同时，提出了以巨势为基础的开放非平衡系热力学第二定律的表述形式，论证了在近平衡区与最小熵产生原理的等价关系。  This paper focuses on a class of linear time delay systems. We are concerned with the design of dissipative static state feedback and dynamic output feedback controllers such that the closed loop system is quadratically stable and strictly (Q,S,R) dissipative. Sufficient conditions for the existence of the quadratic dissipative controllers are obtained by using a linear matrix inequality (LMI) approach. Furthermore, we provide a procedure of constructing such controllers from the solutions of LMIs. It is... This paper focuses on a class of linear time delay systems. We are concerned with the design of dissipative static state feedback and dynamic output feedback controllers such that the closed loop system is quadratically stable and strictly (Q,S,R) dissipative. Sufficient conditions for the existence of the quadratic dissipative controllers are obtained by using a linear matrix inequality (LMI) approach. Furthermore, we provide a procedure of constructing such controllers from the solutions of LMIs. It is shown that the solvability of dissipative controller design problem is implied by the feasibility of LMIs. The main result of this paper unify the existing results on H ∞ control and passive control for linear time delay systems.  研究了一类线性时滞系统的二次耗散控制问题 ,基于线性矩阵不等式 (LMI)方法导出了耗散控制器存在的充分条件 .通过线性矩阵不等式的可行解构造出耗散态状态反馈和动态输出反馈控制律 ,相应的闭环系统是二次稳定和严格 (Q ,S ,R)耗散的 .本文的主要贡献是统一了线性时滞系统现有的H∞ 控制和无源控制结果   << 更多相关文摘 
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