液相色谱测定土壤中4种硝基苯胺类化合物

建立了索氏提取-液相色谱-紫外检测器(SE-HPLC-UV vis)测定土壤中4种硝基苯胺同系物的方法。在以Hypersil BDS C18为色谱柱,55%甲醇为流动相,流速1 mL/min,检测波长230 nm时,4种物质可以在10 min内实现良好分离。对于索氏提取,本研究指出,采用二氯甲烷作为提取剂,能极大地消除HPLC-UV vis检测中的背景干扰。在单因素实验的基础上,得出最佳的提取条件如下:温度55℃,时间8h,提取剂用量60 mL。方法回收率>90%,RSD在1.9%～4.1%之间。     

Synthesis and Crystallization of a Cyclic Decapeptide GG-110824

A highly hydrophobic cyclic peptide GG-110824,cyclo（Gly-Leu-Val-Leu-LeuVal-Pro-Ile-Gly-Leu）（C49H86N10O10）,has been synthesized by a strategy combined with solid-phase synthesis（SPPS） of linear peptide and cyclization in solution.The structure including the absolute configuration of synthesized GG-110824 was confirmed by CuK radiation X-ray crystallography in the monoclinic system,space group P21 with a = 11.4966（10）,b = 18.5286（2）,c = 13.3943（10）,= 95.03o,V = 2842.20（4）3,F（000） = 1080 and Z = 2.     

PAR螯合树脂相光度法测定钯

树脂相光度法是一种灵敏、快速、简单的分离富集与测定同时进行的新型方法[1 ,2 ] 。该方法以离子交换树脂作载体 ,直接对显色树脂进行光度测定 ,避免了洗脱、分离等复杂过程 ,使灵敏度得到了很大提高 ,迄今为众多研究者关注[3] 。铂族金属钯的光度分析法报道较多[4] ,但迄今少见用树脂相光度法测定钯的报道。星野仁等[5 ,6] 指出在ＥＤＴＡ ＮａＯＨ 硼砂介质中 ,ＰＡＲ Ｐｄ(Ⅱ )配合物与十四烷基二甲基苄基氯化铵形成离子缔合物 ,该缔合物能被ＣＨＣｌ3定量萃取 ,其摩尔吸光系数为 3.2 9× 1 0 4 ,方国桢等[7] 确定了在ＥＤ ＴＡ ＮａＯ…     

金属镍配合物的合成及其在烯烃异构化反应中的应用*

设计了一个无机化学教学实验,内容包括:(1)催化剂前体Ni[P(OEt)3]4的合成;(2)无水无氧条件下原位生成催化剂HNiL+3[L=P(OEt)3]及2-丙烯基苯的异构化反应。实验中使用高效液相色谱仪检测烯烃异构化反应的结果,并推测了异构化反应可能的机理。根据学生的实验数据,深入地分析了影响合成催化剂前体产率和烯烃异构化反应转化率的因素。该实验能够使学生在无水无氧操作、低温反应、微量反应的控制等方面得到训练,并且能够掌握高效液相色谱仪的使用原理和测试方法。     

教学管理中的数学模型

针对教学管理的需要 ,在总体服从正态分布的假设下 ,通过控制总体的某项指标 (均值 y或及格率 r) ,分别给出了相应的加分数学模型 .该模型具有合理性、普适性、保序性以及实用性 .通过对模型的检验表明 ,效果相当令人满意 .     

Metastable Phase Separation and Concomitant Solute Redistribution of Liquid Fe-Cu-Sn Ternary Alloy

Liquid Fe-Cu-Sn ternary alloys with lower Sn contents are usually assumed to display a peritectic-type solidification process under equilibrium condition. Here we show that liquid Fe47.5Cu47.5Sn5 ternary alloy exhibits a metastable immiscibility gap in the undercooling range of 51-329 K （0.19TL）. Macroscopic phase separation occurs once undercooling exceeds 196 K and causes the formation of a floating Fe-rich zone and a descending Cu-rich zone. Solute redistribution induces the depletion of Sn concentration in the Fe-rich zone and its enrichment in the Cu-rich zone. The primary Fe phase grows dendritically and its growth velocity increases with undercooling until the appearance of notable macrosegregation, but will decrease if undercooling further increases beyond 236 K. The microsegregation degrees of both solutes in Fe and Cu phases vary only slightly with undercooling.     

固相萃取分离-气相色谱-质谱法测定尿中18种邻苯二甲酸酯类增塑剂

在尿样中加入混合同位素内标(D4-DBP和D4-DEHP)后,使之通过自制的SPE柱(取LC-C18填料,Envi-carb填料和PSA填料装入于玻璃柱中,用旋涡混合器使之混匀)对尿样中存在的邻苯二甲酯类化合物(PTA′s)进行SPE。SPE柱用正己烷-乙酸乙酯(1+1)混合液洗脱。用DB-5MS毛细管柱进行色谱分离,质谱分析中采用EI离子源和SIM模式进行测定,所测18种PTA′s在一定质量浓度范围内与峰面积呈线性关系,检出限(3S/N)在0.002 5~0.005mg·kg-1之间。加标回收率在80.0%~120%之间,测定值的相对标准偏差(n=6)在2.5%~14%之间。     

Effects of BaF2 on Preparing Mullite with Sludge from the Aluminum Profile Factory and Pyrophyllite

In this study, sludge from the aluminum profile factory and pyrophyllite were used as major raw materials to prepare mullite. Through determining optimum formula, the optimum calcination temperature and optimum temperature retention time as well as the effects of BaF2 mineralizer on the crystal structure, microstructure and properties of mullite were studied and the optimum BaF2 mineralizer dosage was determined. With XRD and SEM methods, the crystal structure and microstructure of each sample were characterized. With Rietveld Quantification method, crystal phase content in each sample was determined and properties of each sample were tested. Based on the comprehensive analysis result, it was determined that optimum BaF2 dosage was 0.5%, the fairly good calcination temperature was 1550 ℃, and the corresponding mullite solid solution content was 95.8%.     

H2Se(X1A1)分子的解析势能函数

使用密度泛函B3LYP方法和 6-311++G**基组,在优化H2Se(X1A1)基态结构,确定其正确离解极限,计算所有两体项和三体项参数基础上,建立了H2Se(X1A1)的多体项展式解析势能函数。其中对处于激发态两体项HSe(A2∑+)的计算,则使用SAC-CI方法。H2Se(X1A1)的等值势能图准确地表现了其结构和势能面的特征。     

轴辐式同城快递网络模式研究

随着快递网点密度的稠密化,网络结构设计优劣直接关系到快递公司的运营成本和服务水平。针对快递公司的同城快递市场,在不改变现有网点规模选址的基础上改变网点的从属,结合轴辐式网络结构模式设计来提升其时效并优化成本和资源投入。以运输成本最小为目标,建立了带分支流向约束的枢纽选址模型,设计了高效的禁忌搜索算法对问题求解并验证了算法的有效性。最后提供相应的集散点选址分配解决方案,有利于整合资源形成规模效应,同时提供了同城快递分区管理依据,避免因网络结构复杂引起管理和运营混乱;从长远来看,有利于节约运营成本,增加其快递网络的柔性,降低运作管理的难度。