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It is important, both theoritieally and pratically, that cthe thermodynamics formula is Proved by partial—derivative relations. This point of view ais fully explained in this paPer. At the same time the author has given out a great many exercises collected from the current essential physical chemistrytextbooks and the examination questions for postgraduate students enrolment in recent yearso·A new method for solution of these questions has been provided by means of mathematics principles. The method is... It is important, both theoritieally and pratically, that cthe thermodynamics formula is Proved by partial—derivative relations. This point of view ais fully explained in this paPer. At the same time the author has given out a great many exercises collected from the current essential physical chemistrytextbooks and the examination questions for postgraduate students enrolment in recent yearso·A new method for solution of these questions has been provided by means of mathematics principles. The method is very efficetive and reliable because it has been brone out by more than 50 examples. 本文阐述了热力学公式证明的共同特征及意义。文中搜集了国内外物理化学书籍中主要热力学公式证明题和近年研究生入学试题,作者将其分类并提出通用解题方法。 The forests in this area were severely ruined by reason of history. Accordingly,what mainly needs to be done is to plant on the desert land and to afforest on the barren hills and the wasteland. However,the current evaluation methods of soils are hardly fit for the local conditions. The characteristic of this kind being taken into consideration, evaluation object was completely confined to the soil itself. On the basis of a great deal of investigation and soil analysis, 10 items of soil texture, bulk density,... The forests in this area were severely ruined by reason of history. Accordingly,what mainly needs to be done is to plant on the desert land and to afforest on the barren hills and the wasteland. However,the current evaluation methods of soils are hardly fit for the local conditions. The characteristic of this kind being taken into consideration, evaluation object was completely confined to the soil itself. On the basis of a great deal of investigation and soil analysis, 10 items of soil texture, bulk density, moisture, gravel content, soil thichness,.O. M. , total N,available P, pH .md calcium carbonate were chosen as evaluation factors on the principle of the combination of an all-round way with major points. And these factors were divided into three kinds of different characteristics, i. e. physica(from the 1st to the 5th) , nutritive (from the 6th to the 8th) ,and chemical (from the 9th to the 10th) in accordance with different properties.Following these,a group of experts was invited to conduct the index gradation and the weight distribution of evaluation factors. And then an expert system was established through a certain technical treatment. Based on the fuzzy mathematics principle,the soil quality was comprehensively judged.To sum up all the present evaluation methods of soils, there are 2 types; the gradation method and the score method. The gradation method is not of qualitive idea. The score method has obvious subjectivity. In order to overcome these shortcomings the fuzzy comprehensive judgement technique was applied to the soil evaluation. J. It uses the index system performed by the experts, which can strengthen objectivity of the results;2. The results were directly acquired by means of a series of operation; 3. Because the result was expressed in a vector, it was more entire than the score method's result which can be expressed by only one numerical value. 根据川江流域防护林区内森林地、宜林地并存,且宜林地占有相当比重的特点,将评价对象仅限定于土壤本身,并选取土壤质地等十项可实测土壤指标为评价因素。在此基础上,邀请众多专家进行土壤质量的指标强度分级和因素权重分配。最后采用模糊数学的综合评判法对土壤质量作出评价。评价结果表明,此套方法对川江流域防护林区土壤质量评价是较为合理的,并较其他方法更具优越性。 Instancing the coach SP141 in this paper, we use an eigensystem realization algorithm (ERA) to research the torsional vibration characteristics(TVC) on automobile power trains (APT), and discuss mainly as follows: the mathematics principle about The Least Realization Identification, the torsional vibration modal test technique, and transfer relationship between the strain mode shape and the displacement mode shape;the analysis to the TVC on APT, etc. 本文以SP141客车为例,运用特征系统“实现”算法研究了传动系扭振特征。文中主要论及:扭振系统特征辨识的数学原理;扭振模态试验技术,并给出应变模态与运动模态间的转换关系;汽车传动系统的扭振特征。
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