材料期刊网

Mechanical properties of WC-Co coatings with different decarburization levels

Xu Wu , Zhi-Meng Guo , Hai-Bin Wang , Xiao-Yan Song

稀有金属 doi:10.1007/s12598-014-0257-8

关键词:

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

Ion sputter erosion in metallic glass-A response to "Comment on: Homogeneity of Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass" by L-Y. Chen, Y-W. Zeng, Q-P. Cao, B-J. Park, Y-M. Chen, K. Hono, U. Vainio, Z-L. Zhang, U. Kaiser, X-D. Wang, and J-Z Jiang J. Mater. Res. 24, 3116 (2009)

Journal of Materials Research

The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.

关键词: room-temperature

Improved Nonlinear Equation Method for Numerical Prediction of Jominy EndQuench Curves

SONG Yuepeng , LIU Guoquan , LIU Shengxin , LIU Jiantao , FENG Chengming

钢铁研究学报(英文版)

Without considering the effects of alloying interaction on the Jominy endquench curves, the prediction results obtained by YU Baihai′s nonlinear equation method for multialloying steels were different from those experimental ones reported in literature. Some alloying elements have marked influence on Jominy endquench curves of steels. An improved mathematical model for simulating the Jominy endquench curves is proposed by introducing a parameter named alloying interactions equivalent (Le). With the improved model, the Jominy endquench curves of steels so obtained agree very well with the experimental ones.

关键词: Jominy endquench curve;nonlinear equation method;alloying interaction parameter;computer simulation

不同烷基酰亚胺的合成及对镥的萃取

刘峙嵘 , 周利民 , 李传茂 , 江小昌

稀有金属 doi:10.3969/j.issn.0258-7076.2006.03.021

合成了7种同一系列新型酰亚胺类萃取剂,并运用元素分析、核磁共振、红外光谱、紫外光谱等测试手段对其物化指标进行了表征.萃取性能表明,烷基酰亚胺萃取稀土镥的能力与骨架空间结构有关.直链烷基酰亚胺萃取镥的能力大于相应的支链烷基酰亚胺,而且随链长的增长萃取能力不断增强.利用斜率法,采取直线线性回归求得镥(Ⅲ)与萃取剂基本上以1:2交换.相同条件下,7种酰亚胺类萃取剂分配比的大小顺序为DOI＞DDI＞DHI＞HAI＞HIBI＞DBI＞BIBI.

关键词: 烷基酰亚胺 , 合成 , 镥 , 萃取

Effect of interstitial hydrogen on cohesive strength of Al grain boundary with Mg segregation

材料科学技术（英文）

The effect of interstitial hydrogen on the cohesion of the Al Sigma=11(113) grain boundary (GB) is investigated based on the thermodynamic model of Rice-Wang using the first-principles density function calculation. The results indicate that interstitial H behaves as an embrittler from "strengthening energy" analysis. The reduced GB cohesion due to the presence of H at the GB is attributed to the low affinity between H and Al, and the weakened bonding of Al atomic pairs perpendicular to GB plane.

关键词: hydrogen;grain boundary;Al-Mg alloys;pseudopotentials;1st-principles

Effect of Interstitial Hydrogen on Cohesive Strength of Al Grain Boundary with Mg Segregation

Xiaoguang LIU , Xiaowei WANG

材料科学技术（英文）

The effect of interstitial hydrogen on the cohesion of the Al ∑=11(113) grain boundary (GB) is investigated based on the thermodynamic model of Rice-Wang using the first-principles density function calculation. The results indicate that interstitial H behaves as an embrittler from "strengthening energy" analysis. The reduced GB cohesion due to the presence of H at the GB is attributed to the low affinity between H and Al, and the weakened bonding of Al atomic pairs perpendicular to GB plane.

关键词: Hydrogen , null , null

BiNbO_4纳米棒的制备及光催化性能研究

赵洁 , 姚秉华 , 冯逸晨

功能材料

采用共沉淀法制备BiNbO4纳米棒。利用X射线粉末衍射仪（XRD）、透射电镜（TEM）、紫外-可见漫反射光谱（UV-Vis DRS）和热重分析（TG/DTA）对其结构、形貌和性质进行表征,并通过紫外-可见分光光度计分析BiNbO4纳米棒光降解罗丹明B来研究其光催化活性。结果表明以五氧化二铌和五水硝酸铋为原料制备得到正交相结构的BiNbO4纳米棒;BiN-bO4纳米棒具有较高的光催化活性,在紫外光下,pH值=3.05,催化剂用量为2g/L时能够有效地降解罗丹明B,降解率受到光源、催化剂浓度和溶液pH值的影响较大。

关键词: 共沉淀法 , BiNbO4纳米棒 , 光催化

基于稀疏随机投影的SIFT医学图像配准算法

杨飒 , 郑志硕

量子电子学报 doi:10.3969/j.issn.1007-5461.2015.03.005

针对尺度不变特征变换(Scale-invariant feature transform,SIFT)算法在关键点特征描述向量阶段计算复杂并且维数较高的现象,提出了一种基于压缩感知理论的SIFT算法.通过压缩感知理论的稀疏特征表示方法,对SIFT关键点特征向量进行提取,将高维梯度导数向量降到低维稀疏特征向量,降低了关键点描述向量维度.采用欧式距离作为关键点的相似性度量, Best-Bin-First(BBF)数据结构避免穷举,使数据的运算量大为减少.实验结果表明,新算法对存在仿射变换的医学图像配准性能优于传统SIFT算法,与当前改进型的SIFT算法相比,本文算法的实时性明显增强.

关键词: 图像处理 , 图像配准 , 尺度不变特征变换 , 特征提取 , 稀疏随机投影

DTPA及其衍生物与乳酸脱氢酶的酶学研究及光谱测定

李伟国 , 祁超 , 刘立岩 , 赵大庆

应用化学 doi:10.3969/j.issn.1000-0518.2005.11.003

分别研究了二乙三胺五乙酸(DTPA)及2种衍生物二乙三胺五乙酸-双二甲酰胺(DTPA-BDMA)和二乙三胺五乙酸-双(异烟肼)(DTPA-BIN)对乳酸脱氢酶活性及酶促反应动力学的影响.结果表明,它们均可以抑制脱氢酶的活性,其抑制类型为竞争性的抑制作用,抑制常数分别为3.37、7.41、8.52μmol/L.紫外差谱结果表明,DTPA及其衍生物可以和酶分子作用,其羧基部分被包埋到分子内部,在酶分子的结合部位存在芳香族的氨基酸残基.DTPA与脱氢酶作用后使酶分子中的色氨酸荧光强度减弱,对酪氨酸的荧光没有明显影响.

关键词: 二乙三胺五乙酸 , 乳酸脱氢酶 , 酶学动力学 , 紫外差谱 , 荧光光谱