液相合成方形PbS纳米晶的光学特性

采用一种简单、温和的液相合成方法制备了PbS纳米晶，利用透射电镜和高分辨透射电镜对PbS纳米晶的形貌与晶型结构进行了表征．研究了PbS纳米晶的光学吸收和光致发光特性，并比较分析了包覆剂聚乙烯吡咯烷酮(PVP)和回流时间对产物光学特性的影响．结果表明：PVP分子链中的O原子与纳米晶表面吸附的游离态Pb原子形成Pb-O配位键，使产物的激子吸收大为减弱，同时引起了表面浅束缚态能量的升高，最终导致了荧光淬灭现象．     

Quantitative study on La~(3+) influx mediated by sodium-calcium exchanger in human lymphocytes

Whether La3+ can enter human peripheral blood lymphocytes by the Na+/Ca2+ exchanger or not and the effect of La3+on the Na+/Ca2+ exchanger activity are examined by fura-2 technique. And that whether La3+ is sequestered by intracellular organelles (mainly endoplasmic reticulum and mitochondria) is studied by this method. La3+uptake is obviously stimulated by pre-treating the cells with ouabain and by removing extracellular Na+, and intracellular La3+concentration ([La3+]i) is directly proportional to its extracellular concentration ([La3+]o). But when [La3+]o exceeds 0.4 mmol/L, the 340/380 nm ratio of fluorescence is no longer varied and the maximum [La3+], is 1.5×10-12 mol · L-1. The higher concentration of La3+ (0.1 mmol/L) increases Na+/Ca2+ exchange-mediated calcium influx, but lower concentration (10 μmol/L) appears to block calcium influx. The results also suggest that cytosolic La3+ is transported by the ATP-dependent Ca2+ pump. Intracellular Ca2+ stores are depleted by ionomycin, and then ion     

环状碳酸酯低聚物的合成及其开环聚合的研究

环状碳酸酯低聚物的合成及其开环聚合的研究陈雨萍魏玮李革（中国科学院化学研究所工程塑料国家重点实验室北京１０００８０）关键词环状碳酸酯低聚物，聚碳酸酯，开环聚合环状单体的开环聚合在合成高聚物方面具有突出的优点，即在聚合过程中没有副产物、热效应低、聚合...     

有机锡聚醚的合成及性质的研究

利用界面缩聚技术,将二烷基二氯化锡、二(β-烷氧羰乙基)二氯化锡与有机二元醇、酚、硫醇反应,制成了一系列新的有机锡大分子化合物.对这些新化合物进行了分子量、红外光谱、TG/DTG测试.对有机锡大分子化合物阻止聚氯乙烯(PVC)热分解性能进行了测定.结果表明,新合成的有机锡聚醚化合物可作为PVC热稳定剂使用.     

Removal of Endotoxin from Human Serum Albumin Solutions by Hydrophobic and Cationic Charged Membrane

Removal of end6toxin from medicine injection is very important, becauseendotoxin withpotential biological activity causes pyrogenic and shock reactions in' mammals-'on...intravenous injection even as law as "an6gram amounts. Endotoxin, a constituent ofpotential contaminant of physiological fluids and aqueous solutions 'and very stable atextreme temperature and PH values. For removing endotoxin from solutions ofbiomolecules, such as HSA, adsorption techniques are usedl.' Many methods forendot…     

四甲基锡在MCM-41分子筛表面的接枝反应及产物性能

研究了真空条件下SnMe4在MCM-41分子筛表面的接枝反应，并用元素分析、ICP、GC-MS、XRD、FTIR、DRS、13C及119Sn MAS NMR、XPS、BET、TPD、TPR等方法对产物的组成、结构和性质进行了表征.结果表明, 两者可以定量地进行化学反应，将确定数目的甲基锡基团接枝在分子筛表面, 形成SnMe3/MCM-41物种；接枝反应发生在分子筛表面上, 不破坏MCM-41分子筛骨架结构；改性分子筛的BET比表面积有所降低，孔体积变小, 表面性质发生变化.四甲基锡在MCM-41上接枝反应的温度为343 K,比它与HY沸石的反应温度(193 K)高得多，并且产物SnMe3/MCM-41的热稳定性也高于SnMe3/HY.     

聚偶氮酯的合成及用于乳液聚合

<正> 偶氮二异丁腈(AIBN)与二元醇反应得到聚偶氮酯(polyazoester),进而可按自由基反应引发单体聚合制备嵌段共聚物,近年来国外已有研究,其所用单体多为1,6-己二醇等低分子二元醇。本实验选用AIBN和PEG 400,用Pinner合成法经改进后制得了聚偶氮酯,分析了该产物的结构和热分解动力学,并使之部分分解引发丙烯酰胺得到了兼具表面活性和引发活性的预聚物。结果表明,这种预聚物用于醋酸乙烯聚合、苯乙烯和     

不同光滑度立方体氧化铁对液晶电光性能的改善

向列相液晶被广泛应用于液晶显示中,但是由于杂质的存在,会导致液晶的驱动电压变大,增加能耗。 为了降低阈值电压和饱和电压,通常向液晶中添加纳米颗粒来提高电光性能。 本文利用水热法制备了表面粗糙和光滑的两种立方体Fe₂O₃纳米颗粒,其形貌均匀,尺寸约550 nm。 将二者分别掺杂到向列相液晶E7中,结果表明,粗糙立方体Fe₂O₃/E7复合体系具有比光滑立方体Fe₂O₃/E7复合体系和向列相液晶E7更优的电光性能,且在掺杂质量分数为0.4%时,其电光性能达到最优,阈值电压和饱和电压分别降低9.9%和11.6%,对比度增大80%,响应时间降低至6.0 ms。 这归因于粗糙立方体Fe₂O₃具有足够的表面积和表面所带电荷更多,所以会更易吸附体系中的杂质离子和减弱杂质离子的屏蔽作用,从而提高了电光性能。     

1，4二环己基取代六元瓜环与Na(Ⅰ)自组装实体的合成与晶体结构

A novel complex of a new 1,4-dicyclohexyl cucurbituril(DCYQ[6]) with sodium(Ⅰ) ion was synthesized, and the crystal structure was determined by X-ray diffraction technique. In this self-assembled entity both the cavity interaction of DCYQ[6] included a nitrate anion and the portal interaction of the dipole carbonyls of DCYQ[6] with sodium cations lead to form self assembled molecular capsules. The crystal structure of the entity shows a packing of the self assembled molecular capsules connected by hydrogen bonds of water molecules. CCDC: 271400.     

亮菌甲素的荧光光度法测定

对亮菌甲素的荧光特性进行了研究 ,发现该物质在四硼酸钠缓冲溶液 (pH 8.8± 0 .0 2 )介质中有很强的荧光性质 ,其激发波长为 2 81nm ,发射波长为 4 62nm ,亮菌甲素浓度在 0 .1～ 4 .5 μg·ml- 1范围内与荧光强度呈线性关系 (F =79.4C +3.4 6,r =0 .9994 )。用荧光法测定片剂中亮菌甲素的含量 ,方法简单、快捷、灵敏度高。