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J.L. Finck 《Journal of The Franklin Institute》1948,245(4):301-317
In this paper the concepts “equilibrium” and “reversibility” are examined from the standpoint of the number of independent variables which define a thermodynamic system. The endeavor is made to show that the number of independent variables which are selected is crucial to the basic concepts as well as to the second law of thermodynamics. If this number is less than the minimum required to define the system completely, the equation of state for the internal energy will be incomplete. It is our practice to employ incomplete equations of state, and this results in processes which we consider to be irreversible. The Kelvin-Planck and Clausius principles are shown to be somewhat related to the first law of thermodynamics, and their validity arises from the fact that the equations of state which are used are incomplete. If these equations were complete, that is, if the number of independent variables were not less than the minimum required to describe the systems completely, we should have complete conversion of heat into work, as well as work into heat. The difficulties in realizing complete equations are considered.The entropy concept is considered in detail, and it is shown that there are serious limitations in its application. 相似文献
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结构方程模型的理论、建立与应用 总被引:16,自引:0,他引:16
结构方程模型在社会科学领域得到越来越多的重视和应用,与传统的研究手段相比,它有显而易见的优点。本文以顾客满意度研究为例,引用ACSI的理论模型,讨论了结构方程模型的建立过程并对它的测量问题做了论述。 相似文献
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Nurcan Kurt 《Journal of The Franklin Institute》2008,345(3):303-317
In this study, an alternative method is presented for the solution of two-dimensional heat equation in a square region. In this method, the solution function of the problem is based on the Green function, and therefore on elliptic functions. The numerical results have been computed for an application example and compared with the results of the well-known method of separation of variables and the finite elements method. The comparison study shows that the present method gives better results than those of the other methods. 相似文献
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挑选47组常用的Skyrme参数,采用Skyrme能量密度泛函结合拓展的Thomas-Fermi展开,用约束的密度变分法,我们计算了208Pb、112~124Sn 、 48Ca 、 96Zr、18O 等丰中子核的中子皮厚度并与实验数据分析抽取的中子皮厚度比较,研究了中子皮厚度与非对称核物质态方程中同位旋相关的对称能项之间的关系。我们发现中子皮厚度随对称能系数 a s 以及对称能在饱和密度附近的斜率L、曲率Ksym的增大呈现近似的线性增大的趋势,对称能越硬的核势确定的中子皮越厚。以反质子湮灭法拟合的参考实验值作为标准,我们给出对称能系数,对称能在饱和密度附近的斜率和曲率的参考范围分别为:as = 30 ~ 35MeV ,L = 20 ~ 100MeV,Ksym = -256 ~ 70MeV。满足这个条件的Skyrme 参数有:SLy0-SLy10、SkM*、SkP、SLy230a、SkMP、SKT1-3、SkI3、MSk1-2、SII 。 相似文献
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广西是有色金属之乡,是铝、稀土、铟、锡、铅、锌等有色金属原材料以及深加工产品的生产大省,随着中国-东盟经济带上升为国家战略,广西加快产业升级,实现产业集聚的要求越来越迫切。而快速的经济发展和迅猛的产业聚集,必然带来巨大的产品检测需求。因此需建立一个检测工程技术公共服务平台,利用工程检测中心先进的理化检测手段,统一为企业提供优质、高效的理化工程检测服务,帮助企业解决制约产业发展的重大工艺技术"瓶颈"问题,降低企业进入成本,实现特色及支柱产业做大做强,更好地建设一个创新型经济产业群。 相似文献
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