碲材料中钠,钾杂质成份的测定

本文揭示了钠、钾受基体元素碲干扰的现象和分析系统中酸度对钠、钾吸光度的影响,在理论上探讨了碲对钠、钾干扰的原因,利用加入盐酸和铝元素的方法分别排除碲对钾、钠的干扰,提出一个方便,实用的测定方法,回收率和RSD分别为95-102%和7.4%。     

Stabilité de la Cohomologie LP au Voisinage de 2 pour les Espaces Localement Symétriques

We give a sufficient condition for stability around 2 of L^p cohomology of a system over locally symmetric space.     

Preparation of α-Adamantyl-substituted Aliphatic Ketones

Russian Journal of Organic Chemistry -     

Structure de la Nor-Mycosporine Glutamine,nouvelle substance isolee de Pyronema omphalodes (Bull ex Fr.) fuckel.

Nor-Mycosporin Glutamin, a new unstable compound isolated from sporulating cultures of $\text{Pyronema omphalodes}$, has the structure (I).     

Elucidation of the structure of a highly efficient blue emitting lithium boron 2-(2-hydroxyphenyl) benzoxazole

We have studied the new blue electroluminescent material (compound 1) synthesized from the reaction of 2-(2-hydroxyphenyl)benzoxazole with LiBH₄ according to Tao's procedure [J. Am. Chem. Soc. 121 (1999) 9447; Appl. Phys. Lett. 75 (1999) 1665] Compound 1 showed the UV and the PL peak at 366 and 432 nm, respectively. The manufactured device (ITO/compound 1(600 Å)/Al) showed the EL peak at 412 nm. However, the structure of compound 1 was not fully identified as examined by experiment. In order to disclose the structure of compound 1, we proposed several possible compounds and calculated each compound, using the following methods. Hartree–Fock with the 3-21G(d) basis set was used for energy calculation and geometry optimizations of those compounds. Excitation energies were obtained from time-dependent density functional theory (TD-DFT) using the B3LYP functional with the 3-21G(d) basis set. As a result, [(box)(boxH)Li]₂ was found to be one of the possible compounds which had the most stable geometry structure. Its optical properties showed remarkably good agreement with the characterization data of compound 1. In addition, the structure of [(box)(boxH)Li]₂ was also compared well with that of LiBq₄ which was reported by the groups of Tao and was argumentatively asserted by Radu and coworkers [J. Am. Chem. Soc. 125 (2003) 880].     

Intensity ratios of forbidden coronal lines of Fe XI at 7892 Å and 3987 Å

The excitation of the lowest (3s²3p⁴) configuration of Fe XI is discussed and theoretical values for the relative intensities of the Fe XI lines at 7892 Å and 3987 Å are presented. Particular attention has been paid to the quality of the atomic parameters involved and, in spite of probably inaccurate rates involving complex configurations (such as 3p³4p), it is shown that the predicted intensity ratio obtained is more nearly consistent with available observations that previously published results.