材料期刊网

THE SYNTHESIS AND MAGNETOSTRICTION OF P rx Ce 1 x Fe 2 COMPOUNDS

Y.X.Li , G.Z.Xu , J.P.Qu , F.G.Liu and B.W.Wang Hebei University of Technology , Tianjin 300130 , China C.C.Tang.G.H.Wu and W.S.Zhan State Key Laboratory for Magnetism , Institute of Physics , CAS , Beijing 100080 , China C.Zhao Tianjin University , Tianjin 300072 , China S.X.Gao Hebei Normal University , Shijiazhuang 050091 , China

金属学报(英文版)

The synthesis and magnetic properties of Pr xCe 1 x Fe 2 have been investigated. The forma tion of Pr xCe 1 x Fe 2 is found to depend strongly on annealing temperature. Pure single phase compound can be synthesized at ambient pressure when x≤0 5. The main phase of the Laves structure can still be observed up to x=0 8. Magnetostriction increases with in creasing x and a largest saturation magnetostriction 200 ppm is observed for x=0.5.

关键词: magnetostriction , null , null

C-S-H 凝胶及其研究方法

杨南如

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2003.02.011

在分析C-S-H凝胶的复杂性和特征的基础上,就测定它的化学组成、C-S-H凝胶中[SiO4]4-四面体的聚合度及其结构的化学和物理的方法作了简要介绍.现代各种测试方法的出现和使用,对C-S-H凝胶的组成和集中[SiO4]4-四面体的聚合结构有了较为完整的概念.

关键词: C-S-H凝胶 , 化学组成 , 凝胶结构 , 测定方法

C-S-H凝胶对Pb(Ⅱ)的吸附固化作用

王昕 , 刘晶 , 汪澜 , 考宏涛

硅酸盐通报

以分析纯Ca(NO3)2·4H2O、Na2SiO3·9H2O、Pb(NO3)2为原料,通过溶液反应法,制备纯净的C-S-H凝胶和掺杂Pb的C-S-H凝胶,研究了C-S-H凝胶在形成过程中对Pb的吸附固化作用及掺杂Pb后C-S-H凝胶的结构变化.结果表明,可溶铅盐由2％增至6％时,C-S-H凝胶对Pb均有良好的吸附固化作用,俘获Pb总量增大.XRD图谱发现掺杂Pb的C-S-H凝胶,其主峰位置发生偏移,出现明显的Ca(OH)2衍射峰.红外测试表明含Pb C-S-H凝胶硅氧四面体的链接方式发生变化,Q2伸缩振动峰向低波数方向偏移,Q1伸缩振动峰吸收强度增加.

关键词: C-S-H凝胶 , Pb(Ⅱ) , 吸附固化

C和W注入H13钢纳米结构和抗腐蚀特性

张通和 , 吴瑜光 , 易仲珍 , 张旭 , 梁宏 , 马芙蓉 , 王晓妍

材料热处理学报 doi:10.3969/j.issn.1009-6264.2001.03.015

用多次扫描电位法研究了C和W单独及双注入H13钢对抗腐蚀特性的影响、抗腐蚀相生成的条件及其对抗腐蚀特性的作用,对改性机理进行了讨论.实验结果表明,碳、钨单独和双注入H13钢钨和碳可在注入层超饱和分布,特征为类高斯分布.双注入可在注入层中形成弥散的碳化钨WC和W2C、中间相Fe2W、铁钨碳化物FeW3C、Fe6 W6C和铁的碳化物Fe5C3,Fe3C,Fe2C等.其形状为丝状纳米相,丝状相沿样品法线生长.这种结构使注入层强化,增强了表面抗腐蚀特性;钨和碳双注入同时具有钨和碳单注入的优势,能更有效地提高H13钢的抗腐蚀性,随着W和C注入剂量的增加,抗腐蚀特性逐步增强;样品W5C5的Jp经55个周期腐蚀后,约为H13钢Jp的1/30.

关键词: C和W注入 , 钢 , 抗腐蚀特性 , 电化学测量

First-principles study on the electronic structure and magnetic properties of metallic antiferromagnet C7H3S2N2

Journal of Magnetism and Magnetic Materials

First-principles full potential linearized augmented plane wave (FPLAPW) calculations have been performed to study the electronic structure and the magnetic properties of 3-Cyanobenzo-1,3,2-dithiazolyl,C7H3S2N2. The density of states (DOS), the total energy of the cell, and the spontaneous magnetic moment of C7H3S2N2 were all calculated. The calculations reveal that the low-temperature phase of the compound C7H3S2N2 has a stable metal-antiferromagnetic ground state, and there exists an antiferromagnetically coupled interactions between the dithiazolyl radical(1), which is in good agreement with experiment. (C) 2006 Elsevier B.V. All rights reserved.

关键词: first-principles;antiferromagnetic states;hybridization;organic;magnets;charge-transfer salts;temperature

配合物[Sm(C7H5O3)2(C4H6NO2S)]·2H2O的热化学研究

杨德俊 , 李旭 , 李强国 , 肖圣雄 , 张应军 , 黄熠

中国稀土学报

将六水氯化钐,水杨酸与硫代脯氨酸3种物质一起反应,制得了一种新的稀土三元固体配合物[Sm(C7H5O3)2(C4H6NO2S)]·2H2O(s).通过红外光谱、热重差热分析、元素分析等手段确定了其结构与组成.在常压、298.15 K下,分别测定了六水氯化钐、水杨酸、硫代脯氨酸和该配合物在混合溶剂(二甲亚砜:乙醇:3 mol·L-1HCI=1:1:1)中的溶解焓,并根据热化学原理得出了298.15 K时配合物[Sm(C7H5O3)2(C4H6NO2S)]·2H2O(s)的标准摩尔生成焓△fHθm=(-2913.73±3.10)kJ·moL-1.

关键词: 稀土配合物 , 六水氯化钐 , 硫代脯氨酸 , 水杨酸 , 热化学

纳米无定形C-S-H凝胶颗粒及其结构表征

崔素萍 , 郭红霞 , 王辰 , 王子明

硅酸盐通报

以无水氯化钙( CaCl2)和水玻璃为原料,通过室温沉淀反应制备了水化硅酸钙(C-S-H)凝胶颗粒.采用SEM、FTIR、XRD、XRF、TEM等对不同C/S和pH值条件下制备的C-S-H凝胶颗粒的形貌和结构进行了表征.结果表明,较低pH值条件下制备的C-S-H凝胶颗粒间呈现不同程度的团聚,-Si-O键之间显示一定的聚合度,其平均粒径在15 ～25nm之间,且呈无定形结构；在pH值较高时,该凝胶颗粒呈半结晶结构.

关键词: 水化硅酸钙(C-S-H) , 凝胶颗粒 , 钙硅比(C/S)

Correlation between the surface state and optical properties of S(6) site and C(2) site in nanocrystalline Eu(3+):Y(2)O(3)

Journal of Alloys and Compounds

Eu(3+) doped Y(2)O(3) nanocrystals are synthesized via precipitation and hydrothermal methods. With the increase of hydrothermal temperature, the number of surface states decreases when nanorods are formed. The decrease of surface states induces the increase in the ratio of S(6) site to C(2) site, and meanwhile results in the spectral red-shift of charge transfer band as well as the enhancement of red emission. The results indicate that the surface states and optical properties have close correlations. (C) 2010 Elsevier By. All rights reserved.

关键词: Luminescence;Hydrothermal method;Nanocrystals;Optical properties;luminescence properties;hydrothermal synthesis;size;eu3+;y2o3;photoluminescence;nanopowders;symmetry;ceramics;phosphor

固体核磁共振技术在C-S-H中的研究进展

孙倩 , 管学茂 , 勾密峰 , 朱建平

硅酸盐通报

C-S-H是水泥水化的主要胶凝材料,其结构直接影响混凝土工程性,由于其结晶度较低,中短程有序,采用固体核磁(NMR)可作为分析其结构的方法之一.本文从C-S-H的模型,NMR中特征参数,平均分子链长(MCL)和聚合度三个角度,对水化龄期、掺合料、钙硅比三个方面进行了综述,并展望了固体核磁技术在C-S-H中的发展趋势.

关键词: C-S-H , 聚合度 , MCL , 核磁共振

Corrosion behaviour of carbon steel in different concentrations of HCl solutions containing H(2)S at 90 degrees C

Corrosion Science

The corrosion behavior of SAE-1020 carbon steel in H(2)S-containing solutions with different concentration of HCl at 90 degrees C was investigated by weight loss, electrochemical measurements, SEM and XRD analysis. The results showed that the corrosion rate of carbon steel increased with increasing HCl concentration. Uniform corrosion was found on the carbon steel surface in H(2)S + HCl solutions, while corrosion cavities were observed in the solution only containing H(2)S. The ratio of Faradaic process of total corrosion process increased with the increase of HCl concentration. The corrosion products were solely composed of mackinawite in the H(2)S-containing solutions with or without HCl. (c) 2011 Elsevier Ltd. All rights reserved.

关键词: Steel;Weight loss;EIS;SEM;XRD;Acid corrosion;acidic chloride solutions;hydrogen-sulfide;aqueous-solution;iron;sulfides;electrochemical-behavior;media;dissolution;impedance;polarization;environments