共查询到19条相似文献,搜索用时 46 毫秒
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宋代大科学家沈括所著的“梦溪笔谈”充分显示了我国古代学者在自然科学方面的成就,沈括不仅广泛的观察了各种化学现象,并且也观察了一些化合物的性质: 卷十九第七条中说:古剑有“沈卢”鱼肠之名。“沈卢”谓其湛湛然黑色也,古人以剂钢为刃,柔铁为基榦,不尔则多断折,创之钢者,刃多毁缺,巨阙是也,故不可纯用剂钢。 相似文献
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合成天然橡膠類似物。現有的一般合成橡膠在某些性質方面還是趕不上天然橡膠,尤其是在較高溫度時7C—125°的某些物理機械性質方面是如此。因此,至今對大的和載重的輪胎,因為發熱利害,還是一部分或全部分需用天然橡膠。很久以前就開始人工合成的、和天然 相似文献
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聚酰胺类是高分子化合物的一种,其研究还开始不久,然而它们在不同的技术和科学方面有很大的意义。特别需要指出,聚酰胺在人造纤维方面的应用。由于它们的出现使能得到一系列具有特殊性能的合成纤维,特别是尼龙66,聚己内酰胺,或称之为卡普纶,普纶,西纶,阿米兰等,由聚ω-氨基十一酸所得的纤维称之为立尔散,或翁地嵌,由聚ω-氨基庚酸所得的纤维称之为艾南以及其他等等。 相似文献
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一、前言最近一个时期以来,人們广泛地研究着杂鏈元素有机高分子。其中含磷的化合物占有相当重要的地位,它們具有一系列宝貴的性貭:抗燃性、耐火性和耐热性。含磷的聚合物中有意思的是,含有—P=N—键的聚合物,它具有很好的耐热性。这一类型化合物研究得最多的是氯化磷腈,它的聚合物具有高弹性,文献上称之为“无机橡胶”。 現在已經制备出一系列磷腈化合物的聚合物同系物——从三聚物、四聚物等等开始,一直到高分子化合物,它們具有一系列重要的性质,并已在工艺方面获得应用:在电气工业上把它当作添加物加到润滑油中,使得包布纤维具有耐火性以及其他的性质。雷蒙雾(R(?)nond)引述了关于氯化磷腈及其聚合物在应用方面的工作概况。氯化磷腈聚合物按其结构而言,是属于无机杂鏈高分子化合物,就是说属于一种固态和液态都能存在着的綫型高分子化合物。含有—P=N—鍵、并带有各种有机基因的高分子是属于元素有机高分子。在这里我們将概述一下磷腈 相似文献
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组合化学在功能材料合成方面的应用 总被引:3,自引:0,他引:3
组合化学方法是当今材料科学和化学领域的研究热点。组合化学方法首先在新药的合成领域得到应用, 很快就以其合成周期短、合成的样品数量大、节约经费等诸多优点而拓展到功能材料的合成等其它领域。组合化学的方法有许多种, 按照反应相的不同可以分为液相中的组合合成法和固相中的组合合成法, 固相组合合成又可以根据所选用的掩模方式的不同而分为二分阴影掩模法、四分阴影掩模法、可移动百叶窗式掩模法等几种, 可以根据材料合成的实际需求加以选择。 相似文献
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Günther Wilke 《Angewandte Chemie (International ed. in English)》1988,27(1):185-206
One hundred years of organonickel chemistry have generated a wealth of new knowledge and a history of examples of accidental discoveries which have finally led to industrial applications. The historical development is associated with the names of Mond, Sabatier, Reppe and Ziegler and, with the methods and techniques available today, many of the original discoveries and unsolved problems are attracting renewed attention. For example, 70 years were to go by before a synthesis first conceived by Sabatier could finally be realized. The path leading from nickel-catalyzed hydrogenation to highly enantioselective homogeneous catalysts is one of the contributions to organonickel chemistry which is described here. 相似文献
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Gabriel Moshenska 《Ambix》2015,62(3):266-286
The analysis of ancient artefacts is a long but largely neglected thread within the histories of archaeology and chemistry. This paper examines Michael Faraday's contributions to this nascent field, drawing on his published correspondence and the works of his antiquarian collaborators, and focusing in particular on his analyses of Romano-British and ancient Egyptian artefacts. Faraday examined the materials used in ancient Egyptian mummification, and provided the first proof of the use of lead glazes on Roman ceramics. Beginning with an assessment of Faraday's personal interests and early work on antiquities with Humphry Davy, this paper critically examines the historiography of archaeological chemistry and attempts to place Faraday's work within its institutional, intellectual, and economic contexts. 相似文献
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Dr. Magnus R. Buchner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(52):12018-12036
Given the alleged extreme toxicity of beryllium and its compounds, it is the least investigated nonradioactive element. However, beryllium exhibits unique properties among the elements and therefore the related coordination chemistry is unprecedented. With the emergence of s-block catalysis and the introduction of low-valent magnesium complexes as versatile reducing agents, the interest in related beryllium compounds also has increased. Therefore, some quite remarkable progress on the coordination and organometallic chemistry of beryllium has been made in the last two decades. This Minireview article gives an oversight over the relatively recent developments in this field of beryllium research. An emphasis is placed on the correlation between the structure and reactivity of the described compounds. 相似文献
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Phase and structural relationships of the sulfur, selenium, and tellurium compounds of the 4d and 5d transition elements of groups IV to VII of the periodic system are discussed. Homologous elements behave very similarly with respect to the chalcogens, and this is particularly the case for niobium and tantalum, and for molybdenum and tungsten. However, zirconium, niobium, and molybdenum have a greater tendency towards formation of chalcogen-poor phases than their homologues hafnium, tantalum, and tungsten. Subchalcogenides are known only for zirconium and niobium. The number of phases and the tendency towards formation of solid solutions are considerably smaller among the tellurides than among the sulfides and selenides. The crystal structures of the telluride phases also differ from those of the sulfide and selenide phases of analogous composition. In addition, a review of the phase and structural relationships of the arsenic and antimony compounds of the 4d and 5d transition elements of groups V to VII is given. 相似文献
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