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151.
The paper contains an analysis of the used of Diefallah's composite integral method of kinetic parameters evaluation. It is
shown that the application of this method should be preceded by the application of an isoconversional method through which
the dependence of the activation energy, E, on the conversion degree,<span style='font-size:10.0pt; font-family:"SymbolProp BT";mso-bidi-font-family:"SymbolProp BT"'>a,
should be established. If Edepends on<span style='font-size:10.0pt;font-family:Symbol;mso-bidi-font-family:Symbol'>a, Diefallah's composite integral
method leads to erroneous results. If Edoes not depend on<span style='font-size: 10.0pt;font-family:"SymbolProp BT";mso-bidi-font-family:"SymbolProp BT"'>a, the
true kinetic model should be comprised in the pre-established set of kinetic models. These observations were checked for two
sets of non-isothermal data, namely: (a) the TG curves corresponding to the dehydration of CaC2O4·H2O; (b) the TG curves corresponding to the thermal decomposition of polyvinyl chloride (PVC). 相似文献
152.
153.
Eugen Scholz 《Fresenius' Journal of Analytical Chemistry》1980,303(3):203-207
Zusammenfassung Karl Fischer-Reagentien, die SO2 und Amin im üblichen Molverhältnis 12 enthalten, können nur mit Pyridin hergestellt werden. Stark basische Amine bewirken eine rasche Zersetzung der Reagenslösung und einen instabilen Endpunkt. Erhöht man den SO2-Anteil soweit, daß das Molverhältnis SO2Amin mindestens 11 ist, geben auch stark basische Amine hervorragende KF-Reagentien. Sie zeichnen sich durch stabile Endpunkte und hohe Reaktionsgeschwindigkeit aus. Besonders vorteilhaft ist die Anwendung als Zweikomponentenreagens, da beide Komponenten absolut lagerstabil und titerkonstant sind.
Karl Fischer Reagents without pyridine
Summary Karl Fischer-Reagents containing SO2 and amine in the normally applied molar ratio of 12 can be prepared only by using pyridine. Strong basic amines lead to a rapid decomposition of the reagent solution and to an instable endpoint. By raising the SO2-content to a molar ratio SO2amine of 11, even strong basic amines can be applied yielding KF-reagents of superior quality. They are characterized by stable endpoints and a high speed of reaction. Application as a two-solution reagent gives an additional advantage, because the single components are absolutely stable for storage and the titre remains constant.相似文献
154.
155.
156.
157.
S.L Segal 《Historia Mathematica》1980,7(1):46-56
In 1934 Helmut Hasse became Professor of Mathematics at Göttingen. Hasse's attitudes and behavior during the Nazi period were representative of the ambiguous position of much of the mathematical community at that time. Various aspects of Hasse's situation make him appear to be almost the ideal example of the apolitical conservative and ideologically naive German academic in extremis. The purpose of this article is to present him as such an example. 相似文献
158.
The current distribution is investigated theoretically in a shielded superconducting film, which is a film deposited on an insulating superconducting ground plate. An exact result is obtained in the case of a thin and wide film on the basis of London's equation. 相似文献
159.
A short review about nonassociative algebraic systems (mainly nonassociative algebras) and their physical applications is presented. We begin with some motivations, then we give a brief historical overview about the formation and development of the concept of hypercomplex number system and about some earlier applications. The main directions discussed are the octonionic, Lie-admissible, and quasigroup approaches. Also, some problems investigated in Tartu, the octonionic approach, Moufang–Mal'tsev symmetry, and associator quantization are discussed. This review does not pretend to be complete as the accent is placed on ideas and not on the techniques, also the references are quite sporadic (there are many authors and results mentioned in the text without references). 相似文献
160.
Eugen Scholz 《Fresenius' Journal of Analytical Chemistry》1988,330(8):694-697
Summary Karl Fischer titration can be applied to many phenols without any interference, though some are oxidized during titration. One-component reagents are to be preferred because they are less sensitive to interferences. Only pyrogallol and aminophenols are oxidized in this case. With two-component reagents dihydroxybenzenes and naphthols are oxidized, too. With coulometric titration interferences are more frequent. The oxidation rate depends on the pH and can be suppressed or minimised by adding salicylic acid to the Karl Fischer reagent. 相似文献