五氯化磷辅助下氨基酸的自组装成肽反应研究

L-α-氨基酸和D-α-氨基酸可与五氯化磷直接发生磷酰化反应，随后自组装成多肽，但β-氨基酸不能成肽，DL-α-氨基酸成肽困难；在SOCl2存在下，α-氨基酸也不能成肽，用电喷雾质谱研究了氨基酸的自组装反应，反应过程中有五元环状的氨基酸五配位磷中间体生成，使用硅烷基保护的氨基酸，在^31PNMR中可观察到五配位磷中间体。     

聚二乙基二烯丙基氯化铵的合成与表征

以二乙基二烯丙基氯化铵为原料采用过硫酸盐水溶液引发体系合成了聚二乙基二烯丙基氯化铵(PDEDAAC).探讨了单体、引发剂和助剂EDTA的浓度及温度对产物的特性粘数和单体转化率的影响,确定了适宜的工艺条件,并用元素分析、FT-IR和1H NMR对产物的结构进行了表征.结果表明,当单体浓度≥3.00 mol/L、引发剂浓度为0.015~0.020 mol/L、EDTA浓度为0.40~0.60 mmol/L、聚合反应温度为50~55℃、反应时间为6 h时,产物的特性粘数可达223 mL/g,单体转化率大于98.00%.     

~(13)C核磁共振研究稀土催化剂聚合双烯的机理

用~(13)C-NMR 方法测定了稀土顺丁二烯和聚异戊二烯链端结构及序列结构,从链端结构推测的聚合活性链端结构与前文是一致的。在聚异戊二烯中存在着“头-头”和“尾-尾”结构,这种结构引起活性链端甲基位置的改变,从而解释了稀土异戊二烯中3,4-链节的形成。测定了不同聚合温度对聚合物中顺、反结构含量的影响,可用活性链端的 anti-syn异构化加以解释。     

Growth, Band Structure and Optical Properties of LiSrBO3 Crystal

The bulk crystal of LiSrBO3 (8.39 g) with a size of 21mm×20mm×15mm was grown by high temperature solution growth method. The relationship between growth habit and crystal structure was discussed. The transmission spectrum shows an UV absorption edge at about 300 nm. The melting temperature of this crystal was determined to be 942 ℃ by DTA-TG measurement. The band structure of the LiSrBO3 crystal was studied by means of the first principle method. An indirect band gap was found to be about 4.0 eV,and a low dielectric constant was estimated to be about 1.9 in terms of theoretical results.     

沥青热解残炭的燃烧特性

与轻质油品(汽油、柴油等)燃烧特性不同,重质燃料油在燃烧时,首先发生燃料的热分解,分解的产物扩散到气相空间发生着火、燃烧,最后剩下固体残炭,然后残炭再着火、燃烧,由于残炭的燃烧属于异相反应,比燃料气与空气的同相反应慢,导致其燃尽时间明显变长,文献[1]给出了沥青和十二烷单滴的燃烧过程温度变化曲线,从曲线可以看出,残炭的燃烧阶段明显比气体的燃尽时间长,而残炭的质量只为沥青质量的10%～20%[2,3]。虽然残炭含量低,但它在整个燃烧过程中占有十分重要的地位;文献[4]利用热重系统研究了渣油热加工的副产物石油焦的燃烧特性,主要从…     

纳米金在DNA生物传感器和基因芯片研究中的应用

综述了近年来纳米金在DNA生物传感器及基因芯片中的研究、应用和发展，并对其在生物科技方面的发展趋势进行了展望。参考文献31篇。     

六元N-杂环配体TIAMPP的合成及其在不对称催化加氢中的应用

在三乙胺的作用下，利用（S）-3-羟甲基-1，2，3，4-四氢异喹啉（（S）-TicOL）和Ph2PCl缩合，得到六元N-杂环配体（S）-TIAMPP．研究了（S）-TIAMPP与Rh（I）形成的手性催化剂[Rh（（S）-TIAMPP）（COD）]BF。在脱氢氨基酸的衍生物中不对称催化加氢的对映选择性和适应性，以及该催化剂对N-苯甲酰基脱氢肉桂酸甲酯加氢过程中温度、压力、反应溶剂、底物与催化剂比例（S／C）对光学收率的影响．结果表明，在S／C=100，15℃，1．0MPa的甲醇溶液中，反应24h，[Rh（（S）-TIAMPP）（COD）]BF。对N-苯甲酰基脱氢肉桂酸甲酯加氢的光学收率可达到96％．     

支撑液膜在线萃取流动注射光度法测定水中挥发酚

酚类污染物是一类重要的污染物，对很多水生生物有毒，并且可通过食物链进行生物富集，因此，挥发酚的检测对环境污染控制和环境保护具有重要意义。苯酚是中国环境优先监测物中6种酚类物质之一。酚类物质的测定方法主要有气相色谱法、液相色谱法、光度法等。4-氨基安替比林（4-AAP）分光光度法是目前国际上普遍采用的标准方法，但该方法操作繁琐。如将此法应用于流动注射自动分析，虽然可以省去繁琐的操作，但废水中其它离子的干扰严重，必须进行预蒸馏才能进行测定，且检测限高，不能满足低浓度分析检测的需要。     

Effect of reaction media on the growth and photoluminescence of colloidal CdSe nanocrystals

Using cadium oxide (CdO) as the Cd precursor and tri-n-octylphosphine selenide (TOPSe) as the Se source, TOP-capped and TOP/tri-n-octylphosphine oxide (TOPO)-capped CdSe nanocrystals were synthesized without the use of an acid. The synthetic approach involved the addition of a TOPSe/TOP solution into a CdO/TOP solution with or without TOPO at one temperature and subsequent growth at a lower temperature. The temporal evolution of the optical properties, namely, absorption and luminescence, of the growing nanocrystals was monitored in detail. A comprehensive examination on the control of the photoluminescence (PL) properties was performed by systematically varying the TOP/TOPO weight ratio of the reaction media. Surprisingly, a rational choice of 100% TOP or 80% TOP was found to produce "quality" nanocrystals when monitored under the present experimental conditions and growth-time scale. The term "quality" is mainly based on the sharp features and rich substructure exhibited in the absorption spectra of the growing nanocrystals, as well as the sharp features in the emission spectra with narrow full width at half-maximum (fwhm). There are two distinguishable stages of growth: an early stage (<5 min) and a later stage. TOP plays a major role in the control of a slow growth rate in the early stage, while TOPO controls slow growth in the later stage. The optical sensitivity of the growing nanocrystals when dispersed in nonpolar or polar solvents was studied, including two size-dependent parameters, namely, the solvent sensitivity (PL intensity) and nonresonant Stokes shift (NRSS). The insights gained from the present study enable a synthetic approach in which high-quality CdSe nanocrystals are achieved with high synthetic reproducibility.     

THE NATURE AND SOURCE OF ESR SIGNAL IN BILIRUBIN

The ESR signals of bilirubin-IXα were studied including the samples treated with free radical generating and inhibiting systems, i.e.X-X0., Fe/EDTA, SOD, mannitol/ascorbate, DTPA, KCN et al.These stable signals all comprise those originated from a semiquinone radical(g=2.0012)and superoxide radical(g₁₁=2.041, g_⊥=2.0040).The latter is shown to be bound with metal ionsespecially iron, chelated by bilirubin.The iron probably comes from bilirubin precursor---hemootobin.Active oxygen free radical scavengers may destroy these radicals.Kinetic curves of regeneration of the bilirubin radicals have been determined.Bilirubin is discussed as"active oxygen trap"in mammatians.