CoNiZ系列合金的结构和马氏体相变性质

利用X射线衍射研究了CoNiZ(Z=Si,Sb,Sn,Ga等)合金在不同热处理条件下的相组成.当Z元素为Sn,Sb时,材料是完全的B2结构;但Z为Si时,材料变成面心立方的γ相.形成B2还是γ相由电子浓度和原子尺寸效应两种因素共同决定.而CoNiGa的研究结果表明,在合金中除了形成B2结构的同时还容易形成γ相,常表现出两相共存的特性.对材料进行不同方式的热处理可以使合金中两相的含量有所消长,γ相含量的多少对CoNiGa合金的马氏体相变有很大的影响.分析指出,两相共存及其所带来的物性变化是CoNiGa铁磁性形状记忆合金非常有利用价值的物理性质.     

气相色谱-质谱联用法测定维生素C泡腾片中的甜蜜素

采用气相色谱-质谱(GC-MS)选择离子监测法(SIM),建立了准确可靠、灵敏度高、快速简便的测定维生素C泡腾片中甜蜜素含量的新方法.样品中的甜蜜素衍生后用有机试剂提取,在选择离子模式下进行测定,以保留时间和特征离子比例进行定性,单离子定量.甜蜜素的线性范围为0.05-10mg/L,检出限为0.6mg/kg,回收率为90.5%-96.9%,相对标准偏差小于4.4%.方法分析所用时间短,结果准确可靠,选择性好,适用于维生素C泡腾片中甜蜜素含量的检验.     

A copper‐based reverse atom‐transfer radical polymerization process for the living radical polymerization of polyacrylonitrile

The reverse atom‐transfer radical polymerization (RATRP) technique using CuCl₂/2,2′‐bipyridine (bipy) complex as a catalyst was applied to the living radical polymerization of acrylonitrile (AN). A hexasubstituted ethane thermal iniferter, diethyl 2,3‐dicyano‐2,3‐diphenylsuccinate (DCDPS), was firstly used as the initiator in this copper‐based RATRP initiation system. A CuCl₂ to bipy ratio of 0.5 not only gives the best control of molecular weight and its distribution, but also provides rather rapid reaction rate. The rate of polymerization increases with increasing the polymerization temperature, and the apparent activation energy was calculated to be 57.4 kJ mol^?1. Because the polymers obtained were end‐functionalized by chlorine atoms, they were used as macroinitiators to proceed the chain extension polymerization in the presence of CuCl/bipy catalyst system via a conventional ATRP process. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 226–231, 2006     

Synthesis of polyacrylonitrile via reverse atom transfer radical polymerization catalyzed by FeCl3/isophthalic acid

FeCl₃ coordinated by isophthalic acid was first used as a catalyst in the azobisisobutyronitrile‐initiated reverse atom transfer radical polymerization of acrylonitrile. N,N‐Dimethylformamide was used as a solvent to improve the solubility of the ligand. An FeCl₃‐to‐isophthalic acid ratio of 0.5 not only gave the best control of the molecular weight and its distribution but also provided rather a rapid reaction rate. The effects of different solvents on the polymerization of acrylonitrile were also investigated. The rate of the polymerization in N,N‐dimethylformamide was faster than that in propylene carbonate and toluene. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in N,N‐dimethylformamide. The rate of polymerization increased with increasing polymerization temperature, and the apparent activation energy was calculated to be 59.9 kJ mol^?1. Reverse atom transfer radical polymerization was first used to successfully synthesize acrylonitrile polymers with a molecular weight higher than 80,000 and a narrow polydispersity as low as 1.22. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 219–225, 2006     

锥形模圆柱体超塑性挤压非局部摩擦分析

为了考虑金属材料表面微凸结构对模具与工件接触区域上的非局部摩擦效应,在锥形模圆柱体超塑性挤压加工分析中,采用Oden等提出的非局部摩擦定律代替经典的库仑摩擦定律,利用主应力法或工程法建立了相应问题的积微分形式的力平衡方程.在简化的情况下,采用摄动法求得所论问题的近似解,并分析了影响应力的非局部效应的相关因素.     

低密度聚乙烯光引发交联机理——Ⅱ.BNB自旋捕捉ESR研究

在光引发剂二苯甲酮(BP)存在下,紫外光辐照低密度聚乙烯(LDPE)所形成的自由基中间体已被自旋捕捉剂2,4,6-三特丁基亚硝基苯(BNB)所捕捉,其自旋加合物自由基已为电子自旋共振(ESR)所特征。现已检测和鉴定到二种自旋加合物:一种是叔碳自由基;另一种是仲碳自由基。它们分别是由BP的激发三重态从LDPE链的支化点和亚甲基团上夺氢所形成的自由基中间体同自旋捕捉剂BNB反应生成的。上述的证据表明:LDPE的光引发交联点主要发生在叔碳和仲碳原子上,且H-型交联点占主导地位。     

液相色谱法测定地质样品中的芳香化合物

发展了用液相色谱法检测地质样品中芳香化合物的方法。对观察到的色谱峰进行了定性分析，了该法对油气地球化学勘探的意义。     

Studies on Solid State Reactions of Coordination Compounds（LXXI）──Solid State Reactions of o－Aminobenzoic Acid with Copper（Ⅱ） Acetate and Formate at Room Temperature

ＳｔｕｄｉｅｓｏｎＳｏｌｉｄＳｔａｔｅＲｅａｃｔｉｏｎｓｏｆＣｏｏｒｄｉｎａｔｉｏｎＣｏｍｐｏｕｎｄｓ（ＬＸＸＩ）──ＳｏｌｉｄＳｔａｔｅＲｅａｃｔｉｏｎｓｏｆｏ－ＡｍｉｎｏｂｅｎｚｏｉｃＡｃｉｄｗｉｔｈＣｏｐｐｅｒ（Ⅱ）ＡｃｅｔａｔｅａｎｄＦｏｒｍ...     

无纺布上的偕胺肟基团鳌合物的氧化还原反应的研究

 采用各种分析方法系统研究了含偕胺肟基因维尼无纺布与Ａｎ³⁺进行氧化还原反应时的化学结构变化、氧化还原与鳌合吸附的关系以及还原产物的结晶结构和形态．结果表明，含偕胺肟基无纺布与Ａｕ³⁺反应时，开始主要是偕胺肟基被氧化成为酰胺基．此外，有部分偕胺基因被氧化成为羧基．Ａｎ³⁺被还原的同时生成约相等当量的氢离子．反应后期或反应温度高时，氢离子生成量增大．实验结果还表明，在反应起始阶段，Ａｕ³⁺与偕胺肟基因会发生鳌合作用．还原生咸的单质Ａｎ形成“玫瑰花”状的小晶粒粘附于无纺布纤维表面．     

还原温度对超细K－Co－Mo催化剂合成低碳醇性能的影响

 用溶胶－凝胶法合成了K－Co－Mo催化剂．样品经不同温度还原后，用于低碳醇的合成．XRD和HRTEM结果表明，样品是超细粒子，粒子尺寸为2～5nm．考察了催化剂的还原温度和反应条件对催化剂性能的影响．实验结果表明，还原温度对催化剂的活性有较大的影响，最佳还原温度为500℃．最佳反应温度范围为310～330℃．升高压力和空速可以提高醇的收率和选择性．在空速14400h－1，压力6．0MPa和温度310℃的条件下，醇的选择性为55．8％，收率为520．0g／（kg·h），MeOH／C2＋OH为0．27．催化剂稳定性良好，在200h的寿命实验中，活性基本不变．与文献中催化剂相比，超细K－Co－Mo催化剂对合成醇具有较高的活性和选择性，尤其是对C2＋OH的合成明显高于其他合成醇催化剂体系．