光学双稳性临界点的相变行为

本文详细地讨论了光学双稳性(OB)的临界现象。理论分析主要以忽略量子涨落的Fokker-Plank方程的静态解为基础。结果发现,OB的临界现象可以纳入Landau二级相变理论的框架,并且有关临界指数之间的关系也服从标度律。 关键词：     

Die Oxydationswirkung von Natrium-1,2-naphthochinon-4-sulfonat

Zusammenfassung Die Reaktionen von Natrium-1,2-naphthochino-4-sulfonat mit -Aminosäuren, primären aliphatischen Aminen, Dicarbonsäuren, aliphatischen -Hydroxysäuren und primären Alkoholen werden beschrieben. In allen diesen Fällen reagiert Natrium-1,2-naphtochinon-4-sulfonat als Oxydationsmittel und wird zu dem entsprechenden Diphenol reduziert.     

A new microanalytical radioactive method for the estimation of the iodine number in linseed oil

Summary A microanalytical radioactive method for the estimation of the iodine number in linseed oil has been fully described. The application of the method was carried out on three varieties of linseed oil, namely: Guiza IV, Indian and Baladi. The relationship between the radioactivity measured on the oil spot and the iodine consumed for saturation is described.A simple equation has been put forward for the direct estimation of the iodine value from the specific activity and the number of counts on the oil spot. The method could be used on different varieties of oils and fats.     

The estimation of the iodine number in edible and industrial oils by radioiodine

Summary The iodine number of twenty-two samples of different fats and oils is determined by ¹³¹I, according to the radiometric method. The values obtained for such samples lie between 7.2 and 154.9. The method is applicable with reproducible results and is recommended to cover any stage of unsaturation.

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Zusammenfassung Die Jodzahl von 22 Proben verschiedener Öle und Fette wird radiometrisch unter Benutzung von Jod-131 bestimmt. Die erhaltenen Werte liegen zwischen 7,2 und 154,9. Das Verfahren liefert reproduzierbare Ergebnisse und ist für jeden Grad von Ungesättigtheit anwendbar.

     

Synthesis of new pyrrolo-[3,4-c]isoxazole, pyrrolo[2,3-d]-[1,2,3]triazole, triazolo[4,5-c]-pyridazine, and dipyrrolo-[3,2-b:3′,4′-d]pyran derivatives

New pyrrolo[3,4-c]isoxazole derivatives were synthesized from the key intermediates 4-cyanopyrrolidin-3-ones in two steps. Pyrrolo[2,3-d][1,2,3]triazoles and triazolo[4,5-c]pyridazine were obtained from 2-arylhydrazono-4-cyano-1-(4′-methoxyphenyl)-3-oxopyrrolidines by refluxing with phenylhydrazine in either ethanol or glacial acetic acid. Aldol self-condensation of 1-aryl-4-cyanopyrrolidin-3-ones afforded dipyrrolo-[3,2-b:3′, 4′-d]pyran derivatives. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1841–1848, December, 2007.     

Root determination by use of Padé approximants

In this paper we describe a new technique for generating iteration formulas — of arbitrary order — for determining a zero (assumed simple) of a functionf, assumed analytic in a region containing the zero. The 1/p Padé Approximant (p0) to the functiong(t)f(z) is formed wherez=w+t, using the Taylor series forf at the pointw, an approxination to the zero off. The value oft for which the 1/p Padé Approximant vanishes provides the basis of iteration formulas of orderp+2.Some known iteration formulas, e.g., Newton-Raphson's, Halley's and Kiss's of order of convergence two, three and four, are directly obtained by settingp=0,1 and 2, respectively.     

Labelling and Fractionating of Black Mamba Venom using 131I and Gel-Filtration Technique

Separation of Black Mamba (Dendroaspis polylepis) venom into three fractions was achieved by the use of Sephadex G-100 filtration method. The first and highest peak of the three separated bands proved to be the lethally toxic. Labelling the venom with nascent¹³¹ I prior to fractionating facilitated the detection and the evaluation of three well resoluted fractions. Comparative separation of non-labelled venom was also carried out side by side with the labelled one to study the advantage of radioactivity on extinction measurements.     

Chemical Behavior of the Thiophene Ring in 2-Acetylthiophenes

The data on the methods of synthesis and chemical properties of the thiophene ring in 2-acetylthiophenes published over the last several years until mid 2007 are reviewed for the first time. Many of the synthesized compounds exhibit interesting biological activity in various fields and are used in the production of pharmaceuticals, agrochemicals, dyes, and electrophotogeneratoragents.     

Production of pyrans, pyridazines, pyrimidines, pyrazines and triazine compounds using benzoylacetonitriles as a precursor

Benzoylacetonitriles are easily available and have high chemical reactivity due to the presence of three active moieties; nitrile, carbonyl, and active methylene functions. This review article represents a survey covering the synthetic strategies leading to five six-membered heterocycles; pyrans, pyridazines, pyrimidines, pyrazines, and triazine compounds; utilizing benzoylacetonitriles as starting precursor since 1985. The reactions are subdivided into groups that cover the synthetic methods of these heterocycles.