Synthesis of poly(ethylene oxide) with pending 2,2,6,6‐tetramethylpiperidine‐1‐oxyl groups and its further initiation of the grafting polymerization of styrene

A new stratagem for the synthesis of amphiphilic graft copolymers of hydrophilic poly(ethylene oxide) as the main chain and hydrophobic polystyrene as the side chains is suggested. A poly(ethylene oxide) with pending 2,2,6,6‐tetramethylpiperidine‐1‐oxyls [poly(4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐co‐ethylene oxide)] was first prepared by the anionic ring‐opening copolymerization of ethylene oxide and 4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl, and then the graft copolymerization of styrene was completed with benzoyl peroxide as the initiator in the presence of poly(4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐co‐ethylene oxide). The polymerization of styrene was under control, and comblike, amphiphilic poly(ethylene oxide)‐g‐polystyrene was obtained. The copolymer and its intermediates were characterized with size exclusion chromatography, ¹H NMR, and electron spin resonance in detail. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3836–3842, 2006     

Determination of 17 kinds of banned organochlorine pesticides in water by activated carbon fiber-solid phase microextraction coupled with GC-MS.

Activated carbon fiber (ACF) as extraction fiber for solid-phase microextraction (SPME) and its application for the analysis of banned organochlorine pesticides (OCPs) were investigated. Firstly, ACF was activated by different concentration of zinc chloride, which indicated that ACF activated by 60% zinc chloride had a reasonable specific surface area, pore volume and pore distribution. Secondly, the parameters for the ACF-SPME procedure, the adsorption and desorption conditions, were also optimized when coupled with gas chromatography-mass spectrometry (GC-MS). Thirdly, the ACF-SPME was used to analyze 17 kinds of OCPs in water. The linearity of most pesticides was found to be between 0.2 and 50 microg/l with GC-MS under the selected ion monitoring (SIM) acquisition mode. The limits of detection (LOD) at the sub microg/l were obtained. The work demonstrated here shows that ACF is a promising alternative for the SPME procedure.     

The greatest prime factor of the integers in a short interval (III)

LetP(x) denote the greatest prime factor of II_z<n≤x+x1/2 n. In this paper, we prove thatP(x)>x ^0.723 holds true for a sufficiently largex. Project supported by the Tian Yuan Itam in the National Natural Science Foundation of China.     

线圈型全光纤偏振器的研究

本文采用等效电流法对线圈型全光纤偏振器进行了分析计算.对应于保偏光纤中两正交传输基模的消光比,提出了一种分析保偏光纤弯曲损耗的新方法,这种方法基于将保偏光纤两个不同偏振模式分别等效为两个普通圆光纤的基模,等效参数通过测量不同偏振模式的模场半径来确定.实验证明这种理论计算方法与实验结果一致.最终,我们研制出的线圈型光纤偏振器在1.31μm工作波长下,实测消光比达30dB以上,工作偏振模式插入损耗≤3dB.     

REDUCTION OF C=C DOUBLE BOND WITH BOROHYDRIDE EXCHANGE RESIN-TRANSITION METAL COMPOUND SYSTEMS

Borohydride exchange resin-transition metal(Co,Ni,Cu,)compoundsystems reduced C=C double to C-C single bond in ethanol.     

铁形态分析进展

本文对Fe（Ⅱ）、Fe（Ⅲ）形态分析在1990－2000年间的发展概况作了综述，内容包括分光光度法、色谱法、流动注射分析法等。引用文献53篇。     

Fabrication of hexaphenylsilole nanowires and their morphology-tunable photoluminescence.

Immersion of nanoporous alumina membranes into saturated solutions of hexaphenylsilole with subsequent solvent evaporation affords aligned organic nanowires. The luminescent properties of the hexaphenylsilole nanowires can be manipulated by varying their morphologies, which were controlled by changing the channel sizes of the alumina templates.     

Synthesis and Characterization of Novel Orange-emitting Iridium（Ⅲ） Complexes with Diphenylquinoline Ligands Containing Fluorinated Substituent

Three new cyclometalated iridium（m） complexes based on ligands of diphenylquinoline with fluorinated subsfituents were prepared, and characterized by elemental analysis （EA）, ^1H NMR, and mass spectroscopy （MS）. The photophysical and electrophosphorescent properties of the complexes were briefly discussed.     

含锆层柱蒙脱石对1,2,4三甲基苯歧化反应的催化作用

用离子共聚法合成了硅锆层柱蒙脱石（ＳｉＺｒＰＩＬＭ）和铁锆层柱蒙脱石（ＦｅＺｒＰＩＬＭ），考察了它们对１，２，４三甲基苯（１，２，４ＴｒＭＢ）歧化反应的催化性能．１，２，４ＴｒＭＢ在催化剂样品上可发生歧化反应和异构化反应，歧化反应选择性达８０％以上．随着催化剂预处理温度的提高，１，２，４ＴｒＭＢ转化率下降，歧化反应选择性和四甲基苯（ＴｅＭＢ）中１，２，４，５ＴｅＭＢ含量则升高．催化剂对１，２，４ＴｒＭＢ歧化反应有择形催化作用，１，２，４，５ＴｅＭＢ和间二甲苯、邻二甲苯为主要产物，并且其含量偏离其热力学平衡组成，ＴｅＭＢ中１，２，４，５ＴｅＭＢ的含量在８５％以上．