化工专业英语Lesson-3.docVIP

word精品文档，可编辑，欢迎下载 Lesson 3 The Second Law of Thermodynamics 热力学第二定律 A1 Thermodynamics is concerned with transformation of energy, and the laws of thermodynamics describe the bounds within which these transformation are observed to occur. 热力学关心的是能量的转化，热力学定律描述了这些转化能够发生的边界条件。 2 The first law, stating that energy must be conserved in all ordinary processes, has been the underlying principle of the preceding chapters. 第一定律指出了在所有普遍的过程中，能量是守恒的，它是前面章节遵循的根本原则。 3 The first law imposes no restriction on the direction of energy transformation. 第一定律对能量转化的方向性没有限制。 4 Yet, all our experience indicates the existence of such a restriction. 然而，经验表明这种限制的存在。 5 To complete the foundation for the science of thermodynamics, it is necessary to formulate this second limitation. Its concise statement constitutes the second law. 为了完善热力学科学的基础，有必要明确表达第二个限制条件，它简洁的陈述构成了第二定律。 B1 The differences between the two forms of energy, heat and work, provide some insight into the second law. 两种形式的能量：热和功之间的不同，为第二定律提供了一些见解。 2 These differences are not implied by the first law. 这些不同是第一定律没有提到的。 3 In an energy balance both work and heat are included as simple additive terms, implying that one unit of heat, such as a joule or BTU, is equivalent to the same unit of work. 在能量平衡中，功和热作为简单的加和项，表明了，一个单位的热，如1J或1BTU，等于相同单位的功。 4 Although this is true with respect to an energy balance. 虽然，对于能量平衡来讲，这是正确的。 5 Experience teaches that there is a difference in quality between heat and work. 经验告诉我们，热和功之间有一个本质的差异。 6 This experience can be summarized by the following facts. 这方面的经验可以从以下事实中总结出来。 C1 First, the efficiency of the transformation from one form of work to another such as electrical to mechanical as accomplished in an electric motor, can be made to approach 100 percent as closely as is desired. 首先，从一种形式的功向另一种形式的功的转换效率接近100%，是我们所向往的，比如，从电能到机械能的转换能够通过电动机来实现。 2 One needs merely to exert more and more care in eliminating irre