Daily Archives: 2009年8月22日

既不能无中生有,也不能无中生无

ResearchBlogging.org

A. Pipkin在1972年出了一本小书叫Lectures in Viscoelasticity Theory。现在多数情况下提到这本书,都是因为A. Pipkin在书中提出了一种流变学作图方法:将物料函数作在Deborah数和Weissenber数组成的坐标系里面,展示出线性粘弹性、牛顿粘性和虎克弹性的各种理想边界。原版图中间非线性区域的一个问号,非常有象征意义,直到今天这里还应该打问号。

我们图书馆恰好有这本藏书,我曾经借出来过。我自问是有“把书读厚”的能力的人,但这本书适合有“把书读厚”强迫症的人看。别看书很薄,它可不跟其他关于Viscoelasticity的薄书那样科普。里面的数学足以吓到人。而那个简单直观的后来广泛使用的图,在原书中很难才翻得出来。事实上,是R. Tanner在1985年的书Enigneering Rheology里再次提出这种作图方式并称之为Pipkin diagram,才受到广泛注意的。

我最近写的一篇小综述,需要介绍这方面历史。查找资料的时候遇到了两个关于A. Pipkin这本书的书评,内容非常有趣。

第一则书评发表在老刊J. Polym. Sci., Polym. Lett. Ed.上(Tschoegl, N. (1973). Lectures on viscoelasticity theory, A. C. Pipkin, Springer-Verlag, New York, Heidelberg, Berlin, 1972. 180 pp. $6.50 Journal of Polymer Science: Polymer Letters Edition, 11 (4), 290-291 DOI: 10.1002/pol.1973.130110417)。书评里提到了这本书的艰深:

As a self-taught for physical chemists the book is unsuitable because of the trememdous condensation and advanced mathematical approach. In the author’s own words: “The reader will soon find that he needs to do some work on the side to fill in details that are omitted from the text…

Few teachers will want to use these notes as text…

同时,也提出了书的语言特点:

The book is remarkably free of misprints and often surprises with delightful turns of phrase such as: This incantation wards of evil spirits if we should want to interchange the order of integration (p. 24); or: Notice that we never needed to calculate the transform of f(x). Notice that we would have been in hot water if we had tried to calculate it, because it doesn’t have a transform. Nevertheless, everything is perfectly all right.

可见,这位加州理工的Tschoegl还是挺爽这本书的。原书在1986年出了2nd Ed.,又见书评,这次是发表在SIAM Review上(Day, W. (1987). Lectures on Viscoelasticity Theory (A. C. Pipkin) SIAM Review, 29 (3) DOI: 10.1137/1029086)。这位教授对书的看法显然跟上面一位不一样。首先,还是关于书中数学省了很多步骤的问题:

There is, of course, much to be said for an approach which makes the subject accessible to a wide readership. On the other hand, viscoelasticity deserves to be studied not only because of its technological applications, important though they are, but because of the considerable mathematical interest of the underlying integro-differential equations. It is regrettable that so influential a book should fail to make this point more forcibly.

评论者还不约而同的拿书中的风趣语言说事,不仅提到了同一句话——那句经典的evil spirit,这位牛津大学的Day还曝出了书中更牛的话:

[T]he book retains many of the stylistic features of the informal lecture, which, while they often make for lively reading, do not always transfer happily to the printed page. Thus, we are told, of uniform convergence, that “this incantation wards off evil spirits,” and we find the first law of thermodynamics summarized as, “you don’t get something for nothing,” and the second law as, “you don’t even get nothing for nothing.” These statements, and other of the same kind, appear unchanged in the new edition; it would have been pudent to delete them.

热力学第一定律是“不能无中生有”,第二定律是“不能无中生无”(you don’t even get nothing for nothing)?想想倒是挺酷的。不过显然Day很不满意这类酷语,认为应该都删掉。

这两个书评唯一的共同点是都没有提到书中Pipkin diagram的重要价值。这是因为就算第二版的书评出来的1986年,离R. Tanner的书出来也不到一年。这些书评,最终都比不上Tanner的书对原书宣传得到位。这个原因值得思考。