A Novel Oxidative N-Demethylation of 12-Membered Macrolide with Lead Tetraacetate

Erythromycin has been extensively used in the treatment of bacterial infections for over 50 years1. In addition to the antimicrobial effect, the quite unique antiinflammatory activity of the erythromycin derivatives has attracted much attention as new the…     

STUDY ON AB-CROSSLINKED POLYMERS Ⅰ. THE SYNTHESIS AND MECHANICAL PROPERTIES OF AB-CROSSLINKED POLYMERS BASED. ON PU/PS

The AB-crosslinked polymers (i.e. ABCP) with polystyrene as chain A and vinyl group blocked prepolymers of polyurethanes (PU) as chain B were synthesized and studied. The results of dynamic mechanical spectrometry (DMS) show that the compatibility between the components A and B can be improved greatly through chemical crosslinking during the formation of ABCPs. This effect is especially pronounced when short chain prepolymers is chosen as one of the components. It is apparent that the degree of crosslinking between the two components plays a major role in determining their compatibility. Copolymerizafion of styrene with maleic anhydride in chain A can improve the compatibility and broaden the damping temperature range. Mechanical properties of the sythesized ABCPs were also studied.     

酞侧基聚芳醚砜和聚芳醚酮共混物的高温流变行为

用锥板粘度计测试了酞侧基聚芳醚砜（ＰＥＳ－Ｃ）和酞侧基聚芳醚酮（ＰＥＫ－Ｃ）及其共混物的熔体流变行为．试样的流动活化能分别为１４５、１３３和１１２ＫＪ／ｍｏｌ．共混物的熔体粘度显著低于ＰＥＳ－Ｃ和ＰＥＫ－Ｃ粘度的对数加和值．并证明试样的熔体流动性和加工稳定性都已达到注射成型工艺的要求．     

DFT方法理论研究星际分子C3S+结构和光谱

在B3LYP／6—31lG(d)水平上对可能的星际分子C3S^ 的各种异构体进行了理论计算研究，得到其几何构型、红外光谱和精确能量以利于实验室和星际观测，讨论了其星际含义，并与其中性分子C3S做了比较．结果表明：C3S^ 有3个稳定的异构体，包括线形、三元环和四元环几何构型．按热力学稳定的异构体依次是直线型具有C∞v对称性的CCCS^ (1)，其次是具有CC桥键四元环构型的cC3S^ (2)，能量最高是三元环构型具有CC环外键的C—cCCS^ (3)。     

The Intelligent Properties of Micro－reactors for Preparating Nanoparticles

TiO2 nanoparticles were synthesized by using micro-reactors. The shape and size of the nanoparticles produced from the original micro-reactors and the five times recycled micro-reactorsmother liquor were investigated on transmission electron microscopy (TEM) by using the original sample, freeze prepared sample, and dyeing treated sample, respectively. UV-VIS spectrometry was used to study the growth process of TiO2 nanoparticles in main reactors. The results showed that micro-reactors with nanometer magnitude had spherical or oval structures, and could restore to their original structure after they were destroyed. The products prepared in the original micro-reactors were similar to that in the micro-reactors recycled for many times, suggesting that the micro-reactors had memory function.     

Al掺杂对尖晶石型Li[Mn(Al)]2O4结构的影响

采用共沉淀法按不同Al掺杂比例x[x=n(Al)∶n(Mn+Al)=0, 0.025, 0.050, 0.100, 0.150, 0.200]制得了Al(OH)3和Mn3O4混合物, 将其与LiNO3按一定比例混合, 在空气中于700 ℃烧结得Li[Mn(Al)]2O4样品. X射线衍射和Raman光谱结果表明, 在0≤x≤0.20范围内均得到了单相的尖晶石型样品, 随着x的增加, 晶胞参数减小, 晶格振动能量增加, Mn(Al)-O的结合增强, 结构稳定性增强.     

CdS/SiO2复合材料的低频Raman散射研究

对用溶胶凝胶法制备的ＣｄＳ／ＳｉＯ２复合材料进行低频Ｒａｍａｎ散射研究，结果表明可从其低频Ｒａｍａｎ散射峰位计算出ＣｄＳ微晶的粒径，两种不同的低频振动模式由激发光的两种偏振方向加以区分，低频Ｒａｍａｎ散射射的二级散射峰根据实验结果加以指认，所得平均粒径结果与透射电镜观察结果有较好的对应关系，复合材料吸收光谱吸收边蓝移与ＣｄＳ纳米子粒径之间存在着密切的关系，实验证明，样品吸收边能量与ＣｄＳ平均粒径的     

偶氮胂-DBS用于光度法测定牛血清白蛋白

在室温下,于pH 2.5的Britton-Robinson缓冲溶液中及非离子表面活性剂OP存在下,牛血清白蛋白(BSA)与偶氮胂-DBS的复合物的最大吸收在514 nm波长处,但显色复合物与试剂空白吸光度之差在370 nm处最大,选择在370 nm处测定,反应迅速完成。非离子表面活性剂OP可提高反应灵敏度及复合物稳定性。乙醇可提高体系灵敏度。BSA的质量范围在0~60.0 mg.L-1范围内符合比耳定律,方法表观摩尔吸光率3ε70 nm=8.58×105L.mol-1.cm-1。方法用于测定血清样品中蛋白质的总量,5次测定值的RSD为0.60%,回收率为98.0%。     

用石英晶体微天平研究表面活性剂在银固态表面上的动态吸附

吸附是表面活性剂的一个重要特征.迄今用于原位监测表面活性剂在固体表面上吸附重量变化的方法尚不多见.近年来压电石英晶体作为一种高灵敏的质量传感器(石英晶体微天平)已被用于大气和溶液中多种微量成分的监测.用石英晶体微天平研究I~-、Br~-和表面活性剂在金电极上的吸附行为亦有报道.本文研究了十六烷基三甲基溴化铵(CTAB)、十二烷基磺酸钠(SDSO)、十二烷基硫酸钠(SDS)在银固态表面上的吸附平衡动力学特性及其吸附机制.     

一阶导数吸光光度法测定碘酸钾碘盐中碘

采用一阶导数吸光光度法测定碘酸钾碘盐中碘 ,线性范围为 0～ 12 μg·ml-1,检出限为1.6μg·ml-1,对盐样进行重复测定 ,相对标准偏差≤ 1.9% ,对样品进行加标回收试验 ,回收率在 97.0 %～ 10 2 .5 % ,结果良好