材料期刊网

EFFECT OF SnO_2 ADDITION ON THE SERVICE LIFE AND ELECTROCHEMICAL PROPERTIES OF Ti/IrO_2,+Ta_2O_5 ANODES IN PHENOLSULFONIC ACID SOLUTION

J.M. Hu , H.M. Meng , D.B. Sun , S.J. Zhang , J.X. Wu and D.J. Yang Beijing Corrosion and Protection Center , Open Laboratory of Corrosion , Erosion and Surface Technology , University of Science and Technology Beijing , Beijing 100083 , China

金属学报(英文版)

Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted by addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.

关键词: metal oxide anode , null , null , null , null

Mean-field theory on mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D

Physics Letters A

The magnetic properties of the mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D, in which A, B, C and D are four different magnetic ions and form four different sublattices, are studied by using the Ising model. And the Ising model was dealt with standard mean-field approximation. The regions of concentration in which two compensation points or one compensation point exit are given in c-a, b-c and a-b planes. The phase diagrams of the transition temperature T-c and compensation temperature T-comp are obtained. The temperature dependences of the magnetization are also investigated. Some of the result can be used to explain the experimental work of the molecule-based ferro-ferrimagnet ((NiaMnbFecII)-Mn-II-Fe-II)(1.5) [Cr-III (CN)6] - zH(2)O. (C) 2003 Elsevier B.V. All rights reserved.

关键词: mixed ferro-ferrimagnet;Ising model;four sublattices;phase diagram;transition temperature;compensation temperature;magnetic-properties;prussian blue;alloy

INVESTIGATION OF THE INTRINSIC PARAMETER ((B)OVER-BAR(2)(R(0))) FOR 3D(5) IONS IN THE CASE OF CHARGE MISFITTING SUBSTITUTION

Radiation Effects and Defects in Solids

The empirical superposition model has been applied to study the zero-field splitting and its stress; dependence for 3d(5) ions in some crystals. In the calculations, the reasonable local lattice relaxation and local compressibility changes have been taken into account in the case of charge misfitting substitution. The calculated intrinsic parameters (b) over bar(2)(R(0)) show good agreement with the normal (b) over bar(2)(R(0)) which is obtained from the 3d(5) ions in many crystals. So, the disparity between the parameter (b) over bar(2)(R(0)) obtained in the case of isocharge substitution and that in the case of charge misfitting substitution shown in the previous literature can be removed and the superposition model is applicable to the case of charge misfitting substitution.

关键词: superposition model;electron paramagnetic resonance;local lattice;relaxation;local compressibility;mn2+;fe3+;zero-field splittings;superposition-model;spinel crystals;mn2+

热压浸渍裂解法制备3D-B Cf/SiC复合材料性能的研究

所俊 , 郑文伟 , 肖加余 , 陈朝辉

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2002.02.010

本文通过先热压后先驱体浸渍裂解工艺制备3D-B Cf/SiC陶瓷基复合材料,以期达到缩短材料制备周期的目的.着重对热压温度、压力、时间等因素进行了研究,得到了可优化材料性能的工艺参数.

关键词: 热压 , 先驱体浸渍裂解 , 陶瓷基复合材料

固溶处理对AM60B+XRE及AZ91D+XRE 镁合金性能的影响

彭立明 , 曾小勤 , 朱燕萍 , 丁文江

材料研究学报 doi:10.3321/j.issn:1005-3093.2003.01.018

研究了添加少量富铈混合稀土的AM60B+xRE及AZ91D+xRE合金(x=0.4、0.8、1.2、1.6和2.0%,质量分数)固溶处理后的显微组织与机械性能.结果表明,添加混合稀土能显著提高合金的抗拉强度σb和屈服强度σ0.2,固溶处理明显提高AZ91D+xRE合金的强度;AM60B+xRE及AZ91D+xRE合金的铸态组织由α(Mg)固溶体、杆状Al11RE3相、颗粒状Al10Ce2Mn7相以及网状Mg17Al12相组成,经过固溶处理后,网状Mg17Al12相完全溶解,只剩下热稳定性较高的Al11RE3相和Al10Ce2Mn7相,随固溶时间的延长,其形态略有改变.AM60B+xRE合金拉伸试样断口呈带局部韧窝的准解理断裂形式,而AZ91D+xRE合金则呈现沿晶断裂+解理断裂的混合断口形态.

关键词: 金属材料 , 镁合金 , 稀土合金化 , 固溶处理

Superposition model parameters (b)over-bar(2) and t(2) for d(5) ion Cr+ in sulfides

Physica B-Condensed Matter

The superposition model has been applied to the studies of the zero-field splitting b(2)(0) for AgGaS2: Cr+ crystal and the uniaxial stress EPR data for ZnS: Cr+ crystal. These studies show that for [CrS4](7-) groups in crystals, the intrinsic parameter (b)over-bar(2)(R-0) approximate to -0.035(8)cm(-1) with the reference distance R-0 approximate to 2.378(20) Angstrom and the power-law exponent t(2) approximate to 14(4). To our knowledge, this is the first time that the superposition model parameters (b)over-bar(2) and t(2) are given for Cr+-S2- combination (or other Crc-X combinations). (C) 1999 Published by Elsevier Science B.V. All rights reserved.

关键词: electron paramagnetic resonance;superposition model;Cr+ ion;AgGaS2;ZnS;zero-field splittings;crystals;transition;mn-2+;fe-3+

稳定同位素标记D₄-罗丹明B的合成及表征

王浩然 , 杨维成 , 涂亚辉 , 杨超 , 方超 , 李美华 , 罗勇 , 吴范宏

应用化学 doi:10.11944/j.issn.1000-0518.2016.08.150374

以全氘代邻二甲苯为同位素标记前体，经氧化得到的D₄-邻苯二甲酸与3-羟基-N,N-二乙基苯胺反应生成稳定同位素标记的D₄-罗丹明B，总收率36.9%。目标产物的结构经质谱（MS）、核磁（NMR）等技术手段表征确认，通过高效液相色谱确定化学纯度高于98.0%，同位素氘丰度大于98.0%。将其作为同位素内标试剂用于果汁中罗丹明B的残留检测，在0.05~50 mg/L范围内呈良好的线性关系，其检出限为5 μg/kg，回收率为96.4%~103.4%，相对标准偏差（RSD）为1.0%~1.2%，具有很高的灵敏度和准确性。为食品安全领域违禁色素的检测提供了一种可靠实用的方法。

关键词: 稳定同位素标记 , D₄-罗丹明B , 合成 , 内标 , 食品安全

稳定同位素标记D4-罗丹明B的合成及表征

王浩然 , 杨维成 , 涂亚辉 , 杨超 , 方超 , 李美华 , 罗勇 , 吴范宏

应用化学 doi:10.11944/j.issn.1000-0518.2016.08.150374

以全氘代邻二甲苯为同位素标记前体,经氧化得到的D4-邻苯二甲酸与3-羟基-N,Ⅳ-二乙基苯胺反应生成稳定同位素标记的D4-罗丹明B,总收率36.9％.目标产物的结构经质谱(MS)、核磁(NMR)等技术手段表征确认,通过高效液相色谱确定化学纯度高于98.0％,同位素氘丰度大于98.0％.将其作为同位素内标试剂用于果汁中罗丹明B的残留检测,在0.05～50 mg/L范围内呈良好的线性关系,其检出限为5μg/kg,回收率为96.4％～103.4％,相对标准偏差(RSD)为1.0％ ～ 1.2％,具有很高的灵敏度和准确性.为食品安全领域违禁色素的检测提供了一种可靠实用的方法.

关键词: 稳定同位素标记 , D4-罗丹明B , 合成 , 内标 , 食品安全

Si-B-C陶瓷涂敷2D C/SiC复合材料的抗氧化性能

左新章 , 张立同 , 刘永胜 , 成来飞 , 龚慧灵

复合材料学报

利用化学气相沉积(CVD)法制备了Si-B-C陶瓷涂敷改性的2D C/SiC复合材料,研究了其在700～1200℃氧化10 h性能和结构的演变规律以及自愈合机制,同时获得了Si-B-C涂层在不同温度氧化后的形貌、组分和物相转变规律.结果表明:涂敷在复合材料表面的Si-B-C陶瓷随温度的升高氧化加快,但氧化程度较低,不深于7μm;随温度的升高,氧化形成的硅硼玻璃黏度降低,挥发增强；当温度达到1200℃时,硅硼玻璃析出SiO2晶体；Si-B-C陶瓷涂敷改性的C/SiC具有优良的抗氧化性能,随氧化温度的升高,复合材料失重率增加,但在1200℃氧化10h后失重率仅为0.47％;此外材料在1000℃氧化后的强度保持率最高,达到91.6％,Si-B-C陶瓷氧化形成的硅硼玻璃可以有效封填裂纹,这是材料具有优良抗氧化性能的主要机制.

关键词: C/SiC , Si-B-C陶瓷 , 涂层 , 氧化 , 形貌 , 自愈合

R_2Fe_(14)B的3d磁性的穆斯堡尔谱学研究

俞祥游 , 曾训一

材料研究学报

根据布居数和铁的磁矩μ~[3],求得250K 以及其它温度下铁的亚点阵的~(57)Fe 穆斯堡尔参数。通过确立的超精细场Hn 和μ的关系,得到约化坐标的μ(T)。表明不同铁晶位其对应态不同。实验点落在布里渊曲线之下。交换积分偏差参数△与Fe-Fe 原子间距的标准偏差S 呈线性关系,表明近邻原子自旋间的交换作用的静电性质。认为交换积分的起伏导致R_2Fe_(14)B 的低T(?)。

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