J.S.Lu 1)
,
I.Odneval 2) and C.Leygraf 2) 1) College of Chemical Engineering
,
Zhejiang University of Technology
,
Hangzhou 310032
,
China 2) Department of Material Science and Engineering
,
Royal Institute of Technology
,
Stockholm
,
100 44
,
Sweden
金属学报(英文版)
Atmospheric corrosion of 304 and 316 stainless steels was studied by field exposure test, in which rain water was collected and analyzed by atomic absorption spectroscope (AAS). Emphasis was put on the dissolution of chromium and nickel from the stainless steels by atmospheric corrosion and rain runoff. AAS analyses shows that the amounts of yearly chromium and nickel dissolution were less than 150ng/cm 2 and 50ng/cm 2 respectively for both 304 and 316 stainless steels. XPS analysis reveals the marked Cr enrichment on the 316 stainless steel after one year field exposure. SEM shows the morphology of corrosion pits on the steel surfaces.
关键词:
atmospheric corrosion
,
null
,
null
,
null
吴崇试
,
潘奕
原子核物理评论
doi:10.3969/j.issn.1007-4627.2002.01.001
系统分析了A≈170区正常形变带[521]1/2-中的ΔI=1颤动现象. 根据旋称伙伴带的跃迁能量提取Δ2 Eγ (I)=[Eγ(I)+Eγ(I-2)]/2-Eγ(I-1)值, 表现出旋称相关的规则上下颤动. 其颤动幅度在低自旋端约为50 keV, 而后随自旋而增大或减小, 大体呈抛物线形. 利用改进的ab公式, 提取了相关的脱耦合系数. 运用Nilsson波函数, 探讨了原子核集体哈密顿量中高阶微扰项的可能形式.
关键词:
正常形变带
,
旋称伙伴带
,
ΔI = 1颤动
,
脱耦合效应
,
改进的ab拟合
Physical Review B
We have investigated the electronic structure, chemical bonding, and equations of state of Zr2Al3C5 by means of the ab initio pseudopotential total energy method. The chemical bonding displays layered characteristics and is similar to that of nanolaminate ternary aluminum carbides Ti2AlC and Ti3AlC2. Zr2Al3C5 could be fundamentally described as strong covalent bonding among Al-C-Zr-C-Zr-C-Al atomic chains being interleaved and mirrored by AlC2 blocks. The interplanar cohesion between covalent atomic chains and AlC2 blocks is very weak based on first-principles cohesion energy calculations. Inspired by the structure-property relationship of Ti2AlC and Ti3AlC2, it is expected that Zr2Al3C5 will have easy machinability, damage tolerance, and oxidation resistance besides the merits of refractory ZrC. Zr2Al3C5 has a theoretical bulk modulus of 160 GPa and illustrates elastic anisotropy under pressure below 20 GPa.
关键词:
solids
Journal of Materials Chemistry
We have investigated the electronic structure and chemical bonding properties of Ti3GeC2 by performing ab initio pseudopotential total-energy calculations. Our results show that the crystal structure of Ti3GeC2 is a characteristic zigzag chain of Ti-C-Ti-C-Ti-Ge, running parallel to the c-axis. The chemical bonding in Ti3GeC2 is anisotropic and metallic-covalent-ionic in nature with significant contributions from metallic and covalent bonds, which result in the combination of metallic and ceramic properties in Ti3GeC2.
关键词:
ti3sic2;pseudopotentials;ceramics
杨林燕
,
张舜
,
吕彤
,
张新建
涂料工业
采用自制的具有聚合物结构的端羟基聚醚型3-羟基-2-萘甲酸衍生物作为合成C.I.颜料红57∶1的第二偶合组分,采用共偶合工艺对C.I.颜料红57∶1进行了水性化改性.研究了衍生物在颜料合成中的最佳添加量,着重讨论了改性后的C.I.颜料红57∶1在水介质中的分散性能.结果表明:衍生物的最佳添加量为理论生成颜料质量的5％;与未改性的颜料相比,改性后颜料粒径缩小一半;离心分散100 min后所得水性色浆比吸光度为0.166,色浆黏度下降至102.7 mPa·s,即改性后的颜料分散稳定性得到了明显提高.
关键词:
C.I.颜料红57∶1
,
共偶合工艺
,
改性
,
最佳添加量
,
分散性能
陆景彬
,
刘运祚
,
孙亮
,
杨东
,
梁国栋
,
王守宇
,
马英君
,
赵广义
,
李险峰
,
崔兴柱
,
李明非
,
霍俊德
,
曾国模
,
竺礼华
,
吴晓光
原子核物理评论
doi:10.3969/j.issn.1007-4627.2005.02.003
在稀土区奇奇核πh11/2(×)νi13/2转动带中, 系统地观测到随转动频率或角动量增加, B(M1)/B(E2)曲线表现出所谓parabola-like形状, 即在增加到某一转动频率或自旋后, B(M1)/B(E2)比值快速增强. 基于推转模型和粒子转子模型关于奇奇核二准粒子转动带磁偶极约化跃迁几率的描述, 对稀土区双奇核的这一行为进行了讨论. 指出该现象的发生与νi13/2准中子转动顺排特性密切相关. B(M1)/B(E2)比值在接近第二带交叉(即BC准中子对顺排)的较高频率处的增强效果, 可以理解为主要来源于带交叉引起的波函数中混合四准粒子成分的结果. 通过对B(M1)/B(E2)比值的增强效果发生在较低频率处的分析, 对稀土区奇奇核πh11/2(×)νi13/2带角动量耦合图像有了进一步认识.
关键词:
高自旋态
,
奇奇核
,
电磁跃迁特性
,
顺排
Zhaojun LIN
,
Zhanguo WANG
,
Wei CHEN and Lanying LIN(Lab. of Sendconductor Materials Science
,
Institute of Semiconductors
,
Chinese Academy of Sciences
,
Beijing 100083
,
China)
材料科学技术（英文）
Samples have been prepared at different temperatures by loading I2 molecules into the cages of zeolite 5A, and the measurements of the absorption spectra have been carried out for the prepared samples. It is shown that I2 molecular clusters are formed in the cages of zeolite 5A,and it is also found that moIecuIar clusters which are bonded with intermoIecuIar forces have an important feature, namely, the intermolecular distance in molecular clusters can be changed on different preparing conditions and the blue shift of absorption edges can not be as the criterion of forming molecular clusters.
关键词:
张维光
,
张莉莉
,
蒋正静
,
杨绪杰
,
汪信
,
陆路德
材料导报
通过固相反应法合成了具有光致变色性质的La(2-x)/3(Ag(0)1-2x/3Ag(I)x)TiO3(简称Ag-LST)钙钛矿结构复合氧化物粉体,采用XRD、XPS、ICP和SEM等实验技术对Ag-LST进行了表征.结果表明,Ag-LST具有立方晶相钙钛矿结构,其表面层元素组成为Ag:La:Ti=0.45:0.60:1.00.研究了Ag-LST的光致变色性质,在紫外光(300W汞灯)下照射Ag-LST 1min,样品的颜色从棕黄色转变为蓝紫色;在可见光(500W氙灯)下照射Ag-LST 1h,样品恢复为原来的棕色.Ag-LST的光致变色性质可能与Ag(0)-Ag(I)相互转换有关.
关键词:
光致变色
,
钙钛矿结构
,
掺杂
,
表征
A.A.Hanna
,
A.I.M.Akarish
,
S.M.Ahmed
材料科学技术（英文）
Phosphogypsum (PG) derived from the dissolution of phosphate ore in H2SO4 has been characterized by using chemical and thermogravimetric analyses, X-ray diffraction and infrared spectrum to give an idea about the future utilization of this waste material. The PG under the investigation was free from the radioactive elements and Cd and contained about 141×10-6 rare earth elements in total, which favors the utilization of this material. PG was formed mainly of gypsum, little anhydrite and quartz and rare kaolinite. It exhibited two large endothermic peaks corresponding to the dehydration of the sample and a small one which may be attributed to the liberation of the residual water that may be found in the soluble anhydrite. Also, an exothermic peak was observed which may be related to the transformation of soluble (γ-anhydrite) to insoluble β-anhydrite. PG exhibited the same absorption bands as that observed for chemical CaSO4.2H2O and natural gypsum samples besides the appearance of a weak band at 840 cm-1 which characterizes the vibration of H2PO4- group.
关键词:
Acta Materialia
By use of the linear-combination-of-atomic-orbital (LCAO) method for a cluster model, we study the alloying effect on chemical bonding in TiH2 systems. In order to verify that the cluster model is suitable for describing the crystal behavior. the electronic structures in pure dihydrides. such as ScH2, TiH2, VH2, YH2, ZrH2 and NbH2 are calculated. Good agreement of the variant trend of the metal-hydrogen interaction with that of the enthalpy of formation for each pure dihydride is found, and the ionic and covalent contributions to the metal-hydrogen interaction are evaluated quantitatively as a reference for judging their contributions in the alloyed TiH2. The alloying effect on the ionic interaction of alloyed TiH2 is somewhat weaker than that on the covalent interaction. It is found that hydrogen makes a stronger covalent bond with the weaker hydride forming elements and hydride non-forming elements rather than the stronger hydride forming elements if there exist Ti atoms in the neighborhood in the alloyed TiH2. This trend can be understood by the orbital bonding analysis. The energy interval and orbital overlap contributions to the interaction between metal and hydrogen atoms are discussed qualitatively. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.
关键词:
bonding;ab initio calculation;hydrides;electronic structure;electronic-structure;intermetallic hydride;hydrogen storage;binding-energy;band-structure;zirconium;dihydrides;clusters;niobium;systems
