Synthesis of N,N,N-4,4＂-Di-（4-methylphenyl）-2,2＇：6＇,2＂- terpyridine-N,N,N-tris（isothiocyanato） Ruthenium（Ⅱ） and Application to Colorimetric Hg^2＋ Sensor

A terpyridine derivative DPTP [di-（4-methylphenyl）-2,2＇：6＇,2＂-terpyridine] was conveniently synthesized from 2-bromopyridine via halogen-dance reaction, Kharash coupling and Stille coupling reaction. Then its corresponding ruthenium complex Ru-DPTP [N,N,N-4,4＇＇-di-（4-methy,phenyl）-2,2＇：6＇,2＂-terpyridine-N,N,N-tris（is,-thi,cyanat,）- ruthenium（H） ammonium] was obtained and fully characterized by IR, UV-Vis, ESI MS and elemental analysis. The MLCT absorption band of Ru-DPTP was blue-shifted from 570 to 500 nm upon addition of Hg^2＋. Among a series of surveyed metal ions, the complex showed a unique recognition to Hg^2＋, indicating that it can be used as a selective colorimetric sensor for Hg^2＋.     

POSITRONIUM EMISSION FROM SURFACE OF Si SUBSTRATES PASSIVATED BY HF ETCHING

In order to develop a low-temperature heat-treatment technique for the prepa-ration of Si substrates to be used in-situ in molecular beam epitaxy (MBE), surface defects of the HF etched and passivated substrates were investegated with a slow positron beam analysis, the analysis system was equipped on-line with the molecu-lar beam epitaxy device. The fraction of positronium (Ps) emission from Si surface at different temperatures was estimated by a "peak-method", after comparing with the reflection high energy electron diffraction patterns, it was concluded that for a HF treated specimen a clean and stable passivated surface suitable to MBE can be obtained by an in-situ low-temperature (about 550℃) treatment. However, the pa-rameters of HF treatment (etching time, HF concentration, etc.) should be precisely adjusted in order to avoid the production of excessive damages on Si surfaces.     

特征p=2的Cartan型李代数S（n,m）的导子代数

文献［１］－［８］讨论了基域特征ｐ＞０的有限维Ｃａｒｔａｎ型代数的导子代数，至今，仅剩下Ｐ＝２时的非限制的Ｃａｎｔａｎ型李代数Ｓ（ｎ，ｍ）的导子代数的结构问题没有解决。     

Vasi(c)k利率模型下永久年金现值变量的分布模拟

在利率积累函数是带有正漂移项的布朗运动的情形下,永久年金现值变量服从逆伽玛分布.当利息力过程是Vasi(c)k过程时,很难得到永久年金现值变量的分布的解析解.首先考虑了利息力过程是Vasi(c)k过程的永久年金,给出永久年金现值变量均值的解析解,其中涉及到超几何函数1F1,并应用Mathematica软件给出了相应的数值解.进一步在Vasi(c)k模型下应用R软件模拟了永久年金现值变量的分布,对于永久年金现值变量的均值,数值模拟的结果与解析解非常接近.     

Stille偶联法合成芳基取代联吡啶衍生物

以2-溴吡啶为原料,采用碘化和Halogen-Dance反应一锅法合成了2-溴-4-碘吡啶,产率提高至65%.利用卤素反应活性的差异,通过选择性Kumada偶联反应方便地合成了2-溴-4-(4-甲基)苯基吡啶,并通过Stille偶联反应合成了一系列二联、三联及四联吡啶,进行了NMR、MS、IR以及元素分析等表征.     

《基础分析化学实验》(第二版)评介

北京大学化学系分析化学教学组编写的《基础分析化学实验（第二版）》，１９９８年由北京大学出版社出版发行。本书第一版于１９９５年出版，由于广大读者的需求，使原准备使用５年的本教材提前告罄。于是作者对第一版进行了认真的审查，根据这几年分析化学实验的新发展、...     

一类三阶非线性系统的全局稳定性

运用“类比法”，在文（１）的基础上，构造了一类三阶非线性系统的李雅普诺夫函数给出了该系统零解全局渐近稳定的充分条件，较大推广了文（１）（２）的结果。