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搅拌铸造工艺参数对AA6061/TiC 铝基复合材料抗拉强度影响的预测

J.JEBEEN MOSES , I.DINAHARAN , S.JOSEPH SEKHAR

中国有色金属学报(英文版) doi:10.1016/S1003-6326(16)64256-5

采用搅拌铸造工艺制备 AA6061/15%TiC (质量分数)铝基复合材料。构建一个经验公式用于预测搅拌铸造工艺参数对 AA6061/TiC 铝基复合材料极限抗拉强度的影响。采用有4因素、5水平组成的中心旋转组合设计方案来减少搅拌铸造实验次数。实验因素包括搅拌速率、搅拌时间、搅拌叶片角度和铸造温度。采用所建立的经验公式和显微组织观察分析这些因素对 AA6061/TiC 铝基复合材料极限抗拉强度的影响。分析结果表明:上述各因素均显著影响复合材料的极限抗拉强度。复合材料极限抗拉强度的变化归因于孔隙率、团簇的形成、TiC 颗粒在晶界的偏析及其在铝基体中的均匀分布。

关键词: 铝基复合材料 , 搅拌铸造 , TiC , 抗拉强度

Preparation of I_2 Clusters and Their Absorption Spectra

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:

Galvanostatic electrodeposition and microstructure of copper (I) oxide film

Materials Research Innovations

Polycrystalline copper (I) oxide films were deposited on stainless steel substrate by galvanostatic electrodeposition method and were characterized by Xray diffraction and scanning electron microscopy. The effect of bath temperature, bath pH and current density on the compositon, grain size, surface texture and surface morphology of the electrodeposited films were investigated. The films deposited at low bath pH (less than or equal to 7) consisted of copper (I) oxide and metallic copper; while the films deposited at bath pH between 8 and 12 and bath temperature of 60 degrees C were pure copper (I) oxide. The preferred orientation of the copper (I) oxide films depended on the relative growth rate of (111) and (200) faces and could be controlled by adjusting the bath pH and/or the cathodic current density. (100)-oriented copper (1) oxide films could be deposited at pH=9 and current densities in the range of 0.25-1 mA/cm(2) while (111)-oriented films could be prepared at pH=12 or at pH=9 using the current densities between 1.5-2.5 mA/cm(2). Computer simulated crystallite shapes showed that the crystal shape changed from octahedral for (100)-oriented film to trucated pyramids and cubs for (111)-oriented film. And they were approved by scanning electron microscopy.

关键词: copper(I) oxide;electrochemical deposition;thin films;microstructure;electrochemical synthesis;thin-films

Mode I and mixed mode I/II fatigue cracking in Ni3Al(CrB) single crystals

Fatigue & Fracture of Engineering Materials & Structures

Nominal mode I and mixed mode I/II fatigue tests were carried out using the intermetallic compound Ni3Al(CrB) in the form of single crystal specimens. The effects of crystal orientation and load mode on fatigue crack initiation and growth were studied. The fracture surfaces of the single crystals were characterized by a cleavage-like appearance and cracking occurred either on a single {111} plane or on multiple {111} planes irrespective of whether mode I or mixed mode I/II loadings were applied. It was found that the crack initiation and growth behaviour are dependent on both crystal orientation and applied loading mode. The cracking behaviour predicted by three mixed mode fracture criteria (MTS, SED and G criteria) in polycrystalline materials under mixed mode loading can be understood from the present results on single crystals.

关键词: fatigue cracking;mixed mode loading;crystallographic orientation;resolved shear stress;Ni3Al(CrB) single crystals;growth;alloy

正常形变带[521]1/2的ΔI=1颤动

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

采用UF法精制I+G产品

张国俊 , 许赵辉 , 刘忠洲

膜科学与技术 doi:10.3969/j.issn.1007-8924.2002.02.010

采用截留分子量(MWCO)1万的卷式超滤膜和截留分子量(MWCO)6 000的中空纤维超滤膜,去除I+G粗品液中影响I+G产品透光的色素、大分子蛋白及可溶性胶体蛋白,不需加碳、压滤等工序,产品透光合格率达100%,产品透光的合格稳定性较现有生产工艺大大提高,该工艺不仅可以省去加碳压滤等工序,而且可以保证产品一次性达到合格产品.

关键词: 肌苷酸 , 鸟苷酸 , 超滤 , 透光

ZnO纳米陶瓷的I-V特性

秦秀娟 , 邵光杰 , 刘日平 , 王文魁

兵器材料科学与工程 doi:10.3969/j.issn.1004-244X.2006.01.012

采用连续成型工艺压制纳米ZnO素坯,常压烧结制备了高密度纳米ZnO陶瓷.场发射扫描电镜显示,纳米ZnO陶瓷体微观组织紧密、晶粒尺寸和密度分布均匀.在小电流区测定了纳米ZnO陶瓷的I-V曲线.结果表明,高密度纳米ZnO陶瓷具有良好的非线性伏安特性,其非线性系数高于传统的ZnO陶瓷.

关键词: ZnO , 纳米陶瓷 , 非线性伏安特性

胰岛素样生长因子-I分析方法的新进展

潘琼 , 赵美萍 , 李元宗

色谱

介绍了检测胰岛素样生长因子-I(IGF-I)的各种样品前处理手段、IGF-I的标记方法,以及通过免疫分析、色谱以及色谱-质谱联用技术、表面等离子体共振(SPR)传感器等方法定量检测IGF-I的最新进展.

关键词: 胰岛素样生长因子 , 分析方法 , 综述

355 nm激光作用下CH3I分子的多光子电离解离

李丽 , 孔祥和 , 张树东 , 刘存海 , 孙志青 , 刘建苹 , 张良芳 , 乔光

量子电子学报 doi:10.3969/j.issn.1007-5461.2007.04.009

利用飞行时间质谱仪在超声射流冷却条件下研究了CH3I分子在355 nm激光作用下的多光子电离解离机制.得到了分子的飞行时间质谱,质谱中有较强的H+、CH+3和I+信号,较弱的C+,CH+、CH+2和母体离子CH3I+信号,CH3I+的出现表明CH3I分子的多光子电离解离(MPID)属母体离子阶梯模式:CH3I分子由双光子共振激发到里德堡C态,处于该激发态的母体分子继续吸收光子上泵浦至电离态形成母体离子CH3I+,碎片离子可由母体离子解离形成.同时结合母体离子及碎片离子的出现势对CH3I分子的多光子电离解离通道进行分析,提出了可能的解离电离通道.

关键词: 光谱学 , 多光子电离解离 , 碘甲烷 , 飞行时间质谱

碘代烷烃分子的C-I断键机理研究

王骏 , 张蓉蓉 , 刘玉柱 , 张冰

量子电子学报 doi:10.3969/j.issn.1007-5461.2009.03.001

利用离子速度成像方法对碘代直链烷烃和环烷烃分子在267 nm下的光解断键机理进行了研究.实验分析了激发态I*(5p2P1/2)和基态I(5p2P3/2)的离子影像,得到其对应速度、角度分布的各向异性参数β值和相对量子产率Φ(I)和Φ(I*).实验发现碘代直链烷烃和环烷烃分子在吸收一个267nm的光子后,都发生快速的C-I断键,直接解离生成激发态I*和基态I原子.与碘代直链烷烃相比,碘代环烷烃分子具有明显不同的角度分布特征,碘代环烷烃分子基态的β值大于激发态.并且随着α碳原子上所取代的烷基变重,Φ(I*)有变小的趋势.

关键词: 光解动力学 , 碘代烷烃 , 离子速度成像 , 共振增强多光子电离 , 相对量子产率

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