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141.
离子表面活性剂胶团对阿斯匹林碱水解反应的影响 总被引:3,自引:0,他引:3
离子表面活性剂胶团对阿斯匹林碱水解反应的影响史振民*刘生昆张祝莲巩育军(延安大学化学系延安716000)关键词表面活性剂,阿斯匹林,碱水解反应,胶团,抑制作用1996-05-04收稿,1996-08-12修回阿斯匹林(ASP),学名为乙酰水杨酸,有较... 相似文献
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144.
阐述了功率GaAsMESFET器件热阻测试中温敏参数VGSF和测试电流Im的选取,给出了1~5W器件典型温敏参数的温度测试系数M与测试电流Im的关系。讨论了测试延迟时间tmd对△VGSF测量值的影响和三种校正方法。 相似文献
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146.
商标数据库存储模式及其检索算法研究 总被引:6,自引:0,他引:6
依据商标专家的先验知识和基于内容的图像检索技术,提出了一种新的商标库存储结构,并依据该存储结构设计了以三级检索算法为核心的实用商标登记注册管理系统,对于检索算法,一级检索采用人工确认,二级检索采用傅立叶描述子作为边缘特征向量,三级检索采用hu不变矩组作为矩特征向量,从而达到提高商标申请注册中的检索速度和查准率。 相似文献
147.
Katsumasa Iwai Yi-Wei Shi Mitsunobu Miyagi Yuji Matsuura 《Optics & Laser Technology》2007,39(8):1528-1531
An improved coating method was proposed in order to form a uniform polymer layer in the fabrication of cyclic olefin polymer-coated silver (COP/Ag) hollow fiber. A COP solution was flowed in a closed loop, in which the silver-coated tube was used as a part of the loop. Owing to the constant flowing speed of the COP solution and the airtight flowing environment, a COP layer was uniformly formed. The hollow fibers attain high performance and deliver multi-wavelength laser light from the infrared to the visible simultaneously. The method was successfully applied to the fabrication of practical hollow fibers with 2 m length for the near and mid-infrared lasers. 相似文献
148.
Ye Lin Feng Zeng‐Guo Zhao Yu‐Mei Wu Feng Chen Shi Wang Guo‐Qing 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3650-3665
A novel cyclic ether monomer 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxy‐methyl}‐3′‐methyloxetane (HEMO) was prepared from the reaction of 3‐hydroxymethyl‐3′‐methyloxetane tosylate with triethylene glycol. The corresponding hyperbranched polyether (PHEMO) was synthesized using BF3·Et2O as initiator through cationic ring‐opening polymerization. The evidence from 1H and 13C NMR analyses revealed that the hyperbranched structure is constructed by the competition between two chain propagation mechanisms, i.e. active chain end and activated monomer mechanism. The terminal structure of PHEMO with a cyclic fragment was definitely detected by MALDI‐TOF measurement. A DSC test implied that the resulting polyether has excellent segment motion performance potentially beneficial for the ion transport of polymer electrolytes. Moreover, a TGA assay showed that this hyperbranched polymer possesses high thermostability as compared to its liquid counterpart. The ion conductivity was measured to reach 5.6 × 10?5 S/cm at room temperature and 6.3 × 10?4 S/cm at 80 °C after doped with LiTFSI at a ratio of Li:O = 0.05, presenting the promise to meet the practical requirement of lithium ion batteries for polymer electrolytes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3650–3665, 2006 相似文献
149.
Zhongfan Jia Qiang Fu Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(12):3836-3842
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 相似文献
150.
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. 相似文献