铀氮化物晶体结构及电子结构

铀氮化物因其独特的物理化学性质及优良的性能而成为核燃料循环系统中重要的燃料材料,是核领域的研究热点材料之一。此外,铀氮化物也被用作抗腐蚀涂层材料,在金属铀的表面腐蚀防护领域具有重要的应用价值。在铀-氮体系中,五种结构铀氮化物,包括NaCl型UN、HgIn型UN、Mn₂O₃型α-U₂N₃、La₂O₃型β-U₂N₃和CaF₂型UN₂,已经被确认并进行了广泛研究。但是到目前为止,由于铀氮化物复杂的非化学计量比问题,导致对上述物相之间的转化关系的认识仍不清楚;而不同化学计量比的铀氮化物由于其电子结构的差异,使得其基本物理化学性质发生了根本的变化。有关铀氮化物晶体结构和电子结构方面的研究是探讨其优异性能起因的第一步,因此引起研究者的广泛关注。本文在归纳和分析大量文献的基础上,结合本课题组在铀氮化物相关方面的研究成果,着重介绍铀氮化物晶体结构和电子结构方面的主要进展,并对铀氮化物相结构的转化规律以及电子结构的演化规律进行总结,以期为铀氮化物的实验研究和功能应用提供参考。     

Structure of silica

Summary 1) Preliminary data have been obtained, indicating the existence of structures of two types in silicathree-dimensional framework and double-chain. 2) A model has been proposed for the structure of silica, which resembles the structure of layer clay minerals. 3) The absorption bands in the range of the OH and (Si–(OH) stretching vibrations have been interpreted. 4) The adsorption centers on silica for proton-donor molecules are the oxygen atoms of OH^– ions and SiOH groups; the adsorption centers for electron-donor molecules are the hydrogen atoms of the accessible SiOH groups. 5) It has been shown that the solid-state lattice vibrations are changed under the influence of adsorption.All-Union Scientific-Research Institute for Petroleum Refining, Moscow. Translated from Zhurnal Strukturnoi Khimii, Vol. 18, No. 1, pp. 97–106, January-February, 1977.     

Structure of convosine

From the roots of the plantConvolvulus subhirsutum Regel et Schmalh. have been isolated seven known alkaloids and one new one, for which, on the basis of spectral characteristics, a comparative study with known alkaloids of the tropane series, and synthesis, the structure of (+)-N-isopropyl-3α-veratroyloxynortropane has been established.     

Structure of oxosecodelterine

Periodic acid does not oxidize delterine, an alkaloid fromDelphinium ternatum. However, the further oxidation of 19-oxodelterine, obtained on oxidation by Marion's method, led to oxosecodelterine, which is a semiacetal formed through the C-7 carbonyl group and the C-10 hydroxy group. The treatment of this compound with sulfuric acid led to oxosecodemethanoldelterine.Abu Ali ibn Sina [Avicenna] Tadzhik State Medical Institute, Dushanbe. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 104–107, January–February, 1988.     

Structure of prangosine

Summary From the results of the UV and IR spectra of pranosine and its conversion products and of oxidation, acetylation, methylation, and Hofmann degradation reactions, it has been established that prangosine has the structure 2;-isopropyl amino-4, 5: 6, 7-furocoumarin.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 2, pp. 117–121, 1967     

Structure of severidinine

A new alkaloid, severidinine, with mp 145–147°C []_D –50.2°, C₁₉H₄₅NO₆, has been isolated from the epigeal part ofKoralkowia sewerzowii Regel. On the basis of the IR, PMR, and mass spectra of severidinine and its transformation products, and also passage to the known alkaloids severidine, the structure of 3-acetylseveridine has been established for severidinine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 488–490, July–August, 1983.