Syntheses of DL-threo-Thiamphenicol via Green Oxidation

IntroductionAqueous hydrogen peroxide is considered to be a“green”oxidant with a high oxidation efficiency due toits low molecular weight,cleanness in the oxidationprocess in which only harmless water is produced,lowcost of production and safe transport…     

讨论式教学法在分析化学教学中的具体运用

针对分析化学的知识体系和要求，运用讨论式教学法组织教学，以切实调动每一位学生的学习积极性，加深对知识的理解和运用，提高学生的综合素质和能力。     

Imaging Properties of Planar Microlens Arrays

The planar microlens arrays is a two-dimensional array of optical component which is fabricated monolithically available. Imaging properties of planar microlens arrays are described, which provide both image multiplexer and erect, unit magnification images.     

基于全反射原理的X荧光分析技术及其应用研究

本文简单介绍了一种目前我国应用很少但很有竞争力的新兴元素分析方法——全反射Ｘ荧光（ＴＸＲＦ）分析技术，我们自行研制的分析装置的最低检测限，对于Ｃｕ靶、Ｍｏ靶达到ｐｇ级，其相对检测限达到ｎｇ／ｇ。作为应用范例，还叙述了一种海洋软体动物“牙齿”的定量分析，并给出了相应的Ｘ荧光谱图和分析结果。     

Electrooxidation of CO on Ru（0001） and RuO2（ 100） Electrode Surfaces

The electrooxidation of CO on Ru(0001) and RuO2(100) electrode surfaces were characterized by cyclic voltammetry,AES and RHEED,The CO adlayer was first partially oxidized at 0.8 V, which is controlled by the attack of oxygen species toward the Ru(0001) surface. The remaining CO aldayer oxidation at 0.55 V is related to the combination of CO molecules with oxygen species already located on the surface,In contrast,successive peaks on RuO2(100) at 0.4 V and 0.72 V are observed ,which shows that CO molecules can directly react with two different lattice-oxygen on the surface to carbon dioxide.     

New Subsidiary Interaction Mode of Counteranions with the Periphery Cavity of Calix[4]pyrroles Binding with the Anion Subunits

Calixpyrroles, an easy-to-make class of neutral macrocycles, are effective and selective receptors for anions in the solution and in the solid state1,2. Their anion recognition characteristics have attracted extensive interest. Various functionalized cali…     

$k$-广义拟树的第一个leap Zagreb 指标

图$G$的第一个leap Zagreb指标定义如下: $LM_1(G)=\sum_(v\in v(G)}d_2(v/G)^2$, 其中$d_2(v/G)$是离点$v$的距离为2的顶点. 令$\mathcal{QT}^{(k)}(n)$是有$n$个顶点的$k$-广义拟树的集合.若$G\in \mathcal{QT}^{(k)}(n)$, 本文给出了图$G$的第一个leap Zagreb指标的范围.     

Structure of Oxygen and CO Adsorption on Ru(0001) Electrode

It is important to understand the chemisorption of oxygen and CO on Ru(0001) surface. CO oxidation at oxygen precovered Ru(0001) surface at low oxygen coverages gave an extremely low CO oxidation rate, and it was also observed that, with a nominal oxygen coverage exceeding ca. 3 mL, rather high CO/CO2 conversion probabilities were achieved1. In the case of coadsorption of CO and oxygen on Ru(0001) surface under UHV conditions, a model comprising two CO molecules in an (22)-O unit cel…     

固相萃取-衍生化-气相色谱-质谱联用法同时测定尿液中4种阿片类物质

公安机关用胶体金尿检法对海洛因滥用者的检测常常受到阿片类镇咳药的干扰，使用传统液-液提取法进行实验室检验，操作效率低，灵敏度不高，无法满足公安机关打击涉毒案件的需要。为此，该研究建立了尿液中吗啡、O ⁶ -单乙酰吗啡、可待因和乙酰可待因4种阿片类物质的固相萃取和衍生化技术结合气相色谱-质谱联用（GC-MS）同时检测方法。尿样用磷酸盐缓冲液调节至pH=6后，经MCX固相萃取柱净化，用N -甲基-N -（三甲基硅烷基）三氟乙酰胺（MSTFA）对吗啡、O ⁶ -单乙酰吗啡、可待因进行衍生化，供GC-MS检测。考察了上样和洗脱流速、淋洗液中甲酸体积分数、洗脱液中氨水体积分数、3%（v/v）甲酸甲醇淋洗液体积和固相萃取柱吹干时间对萃取效果的影响。确定上样和洗脱流速1.0 mL/min，淋洗液中甲酸体积分数3%，洗脱液中氨水体积分数5%，3%（v/v）甲酸甲醇淋洗液体积1 mL，吹干时间1 min为最佳条件。在此条件下，4种阿片类物质在0.02~0.8 μg/mL范围内线性关系良好（r ² ≥0.998），检出限（LOD）为0.0016~0.0039 μg/mL，定量限（LOQ）为0.0054~0.0128 μg/mL，当标准添加水平为0.02、0.1、0.2 μg/mL时，回收率为93.0%~110.3%。该方法结合自动化技术，对固相萃取条件精确控制，操作简便、快速、灵敏、准确，适合尿液中吗啡等4种阿片类物质快速测定，可用于海洛因吸食者的大规模监控，并能准确排除因服用含阿片类镇咳药导致的吗啡胶体金尿检假阳性。