高效液相色谱-串联质谱法测定染发剂中11种苯胺和苯酚类染料

1引言在众多染发剂产品中,人工合成的氧化型染发剂由于染色效果好、色调丰富、颜色持久等优点,应用极为广泛。但这类染发剂多以芳香胺和/或酚类组分为有效成分,易引起人体过敏等不良反应,长期使用甚至可能导致"三致"。鉴于氧化型染发剂的安全性问题,我国《化妆品卫生规范》明确规定了其禁用和暂时允许使用组分的类别及限制条件,并推荐     

同步辐射计算机断层技术光源误差机理分析

基于同步辐射X射线的优越特性及计算机断层重建技术对材料无损检测等优点,同步辐射计算机断层重建技术被广泛应用于很多领域.本文对光源非均匀、过饱和以及过穿透的三种情形所引起同步辐射计算机断层技术重建误差的形成机理进行了分析研究,给出了三种情形所引起误差的基本形式.在此基础上,对这三种误差进行了数值模拟,模拟结果证实了分析的正确性. 关键词： 同步辐射 计算机断层 光源 误差     

镍氢电池的循环性能与活性物质微结构的研究

与循环试验大致同步, 用静态(初态和终态)或准动态(增加若干个中间态)的模式对MH/H电池循环性能、电极(包括负极和正极)材料的微结构进行了X射线衍射(XRD)研究, 发现循环性能衰减与正极材料β-Ni(OH)₂的点阵参数、平均晶粒尺度、微应变和总的层错几率均随循环周期增加而减小以及负极材料中腐蚀产物A(OH)₃和B相出现和增加有一定的对应关系, 发现MH/Ni 电池循环性能的衰减是正极材料和负极材料的结构和微结构随着循环次数的增加发生明显变化, 恶化了正负极材料的电化学性能, 同时消耗和恶化了电解液的综合结果. 为了提高电池的循环性能, 采用不同正极材料的添加剂. 结果表明, CaF₂和Lu₂O₃有明显的效果, 其中CaF₂效果最好, 并有广泛的实用性.     

Nonclassical Properties of Multiple-Photon-Added Two-Mode Squeezed Coherent States

We investigate how the photon addition operation affects the nonclassical properties of the non-Gaussian squeezed state generated by adding photons to each mode of the two-mode squeezed coherent state (TMSCS). By the generating function of two-variable Hermite polynomials, the compact expression of normalization factor is derived. We show that the fields in such states exhibit remarkable sub-Poissonian photon statistics. The photon addition operation can enhance the cross-correlation for appropriate combinations of several parameters involved in the TMSCS. Compared with that of TMSCS, the Wigner function of the photon–added TMSCS (PA-TMSCS) is modulated by a factor which is also related with two-variable Hermite polynomials. Such Wigner functions have some negativity regions and show a strong quantum mechanical interference. In addition, the normalization factor, Mandel’s Q parameter, cross-correlation function and Wigner functions are all sensitive to the compound phase involved in TMSCS.     

钛宝石激光抽运的被动锁模Tm:YAG陶瓷激光实验研究

本文采用连续钛宝石激光作抽运,掺杂浓度为6 at.%、长度为2.7 mm的Tm:YAG陶瓷作增益介质,通过引入半导体饱和吸收体获得了稳定的被动锁模运转.实验中获得的激光锁模功率为116.5 mW,中心波长为2007 nm,重复频率为109 MHz,通过自行搭建的腔外非共线强度自相关测量得到的脉冲宽度是55 ps.     

分离X射线衍射线多重宽化效应的新方法和计算程序

在近似函数的基础上，提出并建立分离微晶与微应力、微晶与堆垛层错、微应力与堆垛层错二重宽化效应的最小二乘法和微晶-微应力-堆垛层错三重宽化效应的最小二乘法，同时编制了相关的计算机求解系列程序.这些方法适用于密堆六方(cph)、面心立方(fcc)和体心立方(bcc)结构.还给出和讨论了几个应用实例. 关键词： 最小二乘法 微结构 X射线衍射 计算程序     

Spectral and laser properties of Yb and Ho co-doped（YLa）2O3 transparent ceramic

Highly transparent Yb,Ho doped(YLa)2O3 ceramic was fabricated by conventional ceramic processing with nanopowders.The absorption and emission spectra of the ceramic was investigated.The energy transfer mechanism between Yb3+ and Ho3+ was also discussed.The strong emission band around 2 μm indicated that the Yb-Ho:(Y 0.90 La 0.10)2O3 transparent ceramic is a promising gain medium for the generation of 2 μm laser emissions.The laser operation of Yb-Ho co-doped(YLa)2O3 ceramic at 2.1 μm is first reported.     

微波辅助萃取-气相色谱测定纺织品中多溴联苯(醚)类阻燃剂

建立了微波辅助萃取-气相色谱-微电子捕获检测纺织品中8种多溴联苯及多溴联苯醚类阻燃剂的方法.通过萃取剂选择实验和正交实验,确定了以25 mL正己烷: 二氯甲烷混合溶剂(2:3, V/V)为萃取剂,萃取温度60℃, 仪器功率400 W,萃取10 min的微波萃取条件,并用流速梯度和柱温程序结合的方法优化了气相色谱分析条件.方法的检出限为0.12～0.99 μg/kg;标准加入回收率为75.5%～112.9%;精密度1.3%～11.8%(n=6),适用于纺织品中痕量多溴联苯(醚)类阻燃剂的监测分析.     

新课改视野下基于加德纳多元智能特征理论的化学教学反思

以加德纳多元智能理论作为教学反思框架构建的理论基础,新课程改革三维目标理论作为教学反思框架构建的应用基础,以案例分析为依托,力求为新一代的化学教师提供一个教学反思的理论框架。     

Enantioselective and solvent-controlled diastereoselective Mannich reaction of isatin imines with hydroxyacetone: synthesis of 3-substituted 3-aminooxindoles

The diastereoselectively switchable enantioselective Mannich reaction of isatin imines with hydroxyacetone is reported. The chiral primary amino acid catalyzed this Mannich reaction to afford both anti- and syn-Mannich adducts in high yields, good diastereoselectivities, and enantioselectivities. The reason for the solvent control of the diastereoselectivity phenomenon was investigated.