New possibilities in the phase analysis of rocks with a derivatograph-C

The advantages of one of the latest generation of thermoanalytical instruments of the Hungarian Optical Works (the Derivatograph-C) are summarized. The paper contains some practical examples of the phase analysis of geological samples.

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Zusammenfassung In diesem Beitrag sind die Vorteile der letzten Generation thermoanalytischer GerÄte (Derivatograph-c) der Ungarischen Optischen Werke zusammengefa\t. Es werden einige praktische Beispiele aus dem Gebiet der Phasenanalyse geologischer Proben beschrieben.

     

钾离子调控的1,5-萘基桥联双冠醚的

报道了萘基桥联双苯并15-冠-5的合成, 研究了K^＋调控的双冠醚自组装过程以及伴随的独特荧光行为. 这种发光行为不仅可以模拟一个荧光"off-on-off"开关和一个荧光"on-off-on"开关, 而且其组装模式和功能上类似于酶的二聚化过程.     

非霍奇金淋巴瘤的研究

非霍奇金淋巴瘤是具有很强异质性的一组独立疾病的总称,在常见恶性肿瘤中排名前10位,对人类健康威胁巨大。近年来,研究者们一直致力于非霍奇金淋巴瘤的发病机制、生物标志物及其治疗的研究,鉴于此,针对非霍奇金淋巴瘤的研究进行深入探讨。     

表面膨胀粘度的测定研究

用不同浓度的NaCl和表面活性剂直链的十二烷基苯磺酸钠(LAS)、稳定剂聚丙烯酰胺和水所组成的泡沫体系为研究对象,通过表面压松弛的方法,利用计算机数据拟合,得到了计算表面膨胀粘度的方法。     

The Ontological Autonomy Of The Chemical World

In the problem of the relationship between chemistry and physics, many authors take for granted the ontological reduction of the chemical world to the world of physics. The autonomy of chemistry is usually defended on the basis of the failure of epistemological reduction: not all chemical concepts and laws can be derived from the theoretical framework of physics. The main aim of this paper is to argue that this line of argumentation is not strong enough for eliminate the idea of a hierarchical dependence of chemistry with respect to physics. The rejection of the secondary position of chemistry and the defense of the legitimacy of the philosophy of chemistry require a radically different philosophical perspective that denies not only epistemological reduction but also ontological reduction. Only on the basis of a philosophically grounded ontological pluralism it is possible to accept the ontological autonomy of the chemical world and, with this, to reverse the traditional idea of the ‘superiority’ of physics in the context of natural sciences.     

新型导电高分子材料的导电性与其结构的关系

新型导电高分子材料的导电性与其结构的关系梁洪泽，宋永贤，丁黎明，綦玉臣，李丽霞，景遐斌，王佛松（中国科学院长春应用化学研究所，长春，１３００２２）自Ｗｒｉｇｈｔ首次报道了聚环氧乙烷（ＰＥＯ）－碱金属盐（ＭＸ）配合物的离子导电性以来，有关各种聚合物固体...     

The problem of fullerenes. The chemical aspect

The preparation, structure, and reactivity of the family of polyhedral carbon clusters, novel allotropes of carbon, are reviewed.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 10–19, January, 1993.     

塑料工业技术开发热点及其市场预测

本文简述了塑科将成为未来世纪的主要工业材料,介绍了80年代至本世纪末,世界主要国家塑料工业的主要品种,产量,生产能力;分析了90年代世界塑料市场供需状况,并重点探讨了中国塑料市场供需矛盾,预测了2000年需求总量,提出了今后发展应注意的关键问题。最后,重点探讨了世界塑料工业几个主要品种,今后发展趋势及一些关键技术的开发热点。     

The aza-

The inclusion of a C-2 trialkylsilyl substituent into allylic amine precursors allows the base-induced aza-[2,3]-Wittig sigmatropic rearrangement to proceed in excellent yield and diastereoselectivity. The rearrangement precursors require a carbonyl-based nitrogen protecting group that must be stable to the excess of strong base required for the reaction. The N-Boc and N-benzoyl group are very good at stabilizing the product anion and initiating deprotonation. The migrating groups (G) need to stabilize the intial anion by resonance and require G-CH(3)() pK(a) > 22 in order for the initial anion to be reactive enough for rearrangement. Products 7, 20b-d,f,g, and 23 are formed with high (10-20:1) anti diastereoselectivity. Product 23 containing the morpholine amide group is useful for preparing other carbonyl derivatives.     

The Helicenes

“Helicene” is the name introduced by Newman in 1955, to describe the benzologues of phenanthrene in which the extra ortho-condensed rings give rise to a (regular) cylindrical helix. The pioneer work of Newman in this field cannot be overemphasized; his brillant synthesis and resolution of [6]helicene, achieved eighteen years ago, will remain as a landmark, for it opened the way to the study of a fascinating class of synthetic molecules. In the following review, an attempt is made to summarize the present state of our knowledge in this rapidly expanding field.     

The Photolysis Of The Endoperoxide Of 9,10-Diphenylanthracene

During the photolysis of the endoperoxide of 9,10-diphenylanthracene, two different reactions are observed, depending on the irradiation wavelength: (i) Excitation of the S₁ band causes a homolytic cleavage of the peroxide bridge with a quantum yield Q₂ = 0.08. (ii) Irradiation of the S₂ band leads to an adiabatic photocleavage of the endoperoxide into 9,10-diphenylanthracene and singlet molecular oxygen with a quantum yield Q₁ = 0.28. Both reaction pathways confirm the theory of Kearns and Khan concerning the photolysis of endoperoxides     

The willgerodt-kindler reactions. 7. The mechanisms

The mechanisms involved in various stages of the Kindler Reaction are discussed, with particular attention especially to its most unusual feature: the movement of a carbonyl group from methylene carbon to methylene carbon in an unbranched alkyl chain, or around a cycloalkyl ring. The first step is the reversible formation of an enamine, which is attacked by a catalyst generated from sulfur and the amine solvent to form a highly reactive intermediate with a sulfur-containing heterocyclic ring. The natures of the catalytically active species and the reactive intermediates are proposed. Other steps involved in the Kindler Reaction are also discussed, as is the relationship of the Willgerodt Reaction to the Kindler Reaction.