Y. L. Zhang1) and G. Spinks2) 1) Departmentof Mechanical Engineering
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Ngee Ann Polytechnic
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535 Clementi Road
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Singapore5994892) Intelligent Polymer Research Institute
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University of Wollongong
,
Northfields Ave
,
Wollongong
,
NSW
,
Australia
,
2522
金属学报(英文版)
Arolled mild steel wascoated byconductive polymers( polyaniline/ MMPand polyaniline/HCSA) andthenim mersedin hot water(50 ℃) fordifferenttimesforstudytheadhesion ofcoatings.It wasfound thatthe adhesion tendsto decrease over time. Thestudyshown that onebrittle and porous Fe3 O4 layer formed between conductive polymercoating and steelsub stratein a moistenvironmentand, asa result, decreased thecoating adhesions.
关键词:
conductive polymercoating
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null
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null
G.Y. Sha
金属学报(英文版)
An experimental-numerical method for measuring dynamic crack propagating veloc-ities under stress wave loading is established in this paper. The experiments of thethree-point bend specimen are done on the improved Hopkinson bar. Deflection ofloading point, dynamic load and instantaneous crack length ave measured, then crackpropagating velocities are calculated. Experiments on 40Cr steel show that the resultsgiven by this method have a good agreement with that obtained by the resistance frac-ture gage method. Therefore this method is feasible for measuring crack propagatingvelocities under high loading rate and will have wide application.
关键词:
stress wave loading
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null
Z.M.Yu
金属学报(英文版)
The surface free energy (SFE) of (1× 1)-surfaces of crystals, without reconstructionand adsorption, is calculated using a bond-broken mode. In the mode, the potentialenergy of the crystals is treated as a sum of the energies of the bonds connectingpair-wise atoms (u-bonds). The SFE is calculated based on the bond energy and thearea density of dangling bonds which depends on the structure of the surface. Theresults provide a general expression for the SFE in terms of the bond energy (E)and the bond length (do) of the crystal and Miller indices hkl. The anisotropy ofthe SFE is therefore completely determined with the expression. As the examples,considering the nearest-neighboring bonding, the SFEs of sc, fcc, bcc and cth (cubictetrahedral) crystals are discussed, respectively. Wulff plots of bcc and fcc crystalsare then obtained. The equilibrium forms (EFs) of these crystals ave consequentlygot from their Wulff plots, respectively. It is found that the EFs of bcc and fcc arerespectively the rhombic dodecahedron and the truncated-octahedron that are their firstBrillouin zones, respectively.
关键词:
surface free energy
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null
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null
G.H. Yu
金属学报(英文版)
Ta/NiO/NiFe/Ta multilayers were prepared by rf reactive and dc magnetron sputter-ing. The exchange coupling field (Hex) between NiO and NiFe reached 120Oe. Thecomposition and chemical states at the interface region of NiO/NiFe were studied us-ing the x-ray photoelectron spectroscopy (XPS) and peak decomposition technique. Theresults show that there are two thermodynamically favorable reactions at NiO/NiFeinterface: NiO+Fe = Ni+FeO and 3NiO+2Fe 3Ni+Fe2 O3. The thickness of thechemical reaction as estimated by angle-resolved XPS was about 1-1.5nm. These in-terrace reaction products are magnetic defects, and we believe that the Hex and thecoereivity (He) of NiO/NiFe ave affected by these defects. Moreover, the results alsoshow that there is an "intermixing layer" at the Ta/NiO (and NiO/Ta) interface dueto a thermodynamically favorable reaction: 2Ta+5NiO＝5Ni+Ta2O5. This interfacereaction has an effect on the exchange coupling as well. The thickness of the "inter-mixing layer" as estimated by XPS depth-profiles was about 8-10nm.
关键词:
spin-valve multilayer
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null
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null
陈瑞
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许庆彦
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柳百成
中国有色金属学报
通过Al-7Si-0.36Mg合金定向凝固实验和元胞自动机模型，开展定向凝固枝晶形貌演化和一次枝晶臂间距选择过程的实验和模拟。结果表明：在给定的凝固条件下，一次枝晶臂间距范围是一个连续的变化区间。在恒定温度梯度和不同凝固速度条件下，测得Al-7Si-0.36Mg合金一次枝晶臂间距上限值(λmax)、下限值(λmin)和平均值(λave)以及生长速率之间的关系，且上限值和下限值的比值接近3。模拟结果与实验结果的吻合程度明显优于Hunt?Lu等解析模型的预测结果，表明CA模型在枝晶定向凝固过程枝晶形貌演化模拟和枝晶臂间距预测等方面的准确性。结合模拟研究和文献调研分析影响定向凝固一次枝晶臂选择的因素，包括抽拉速度v、温度梯度G、界面能大小、溶质扩散系数DL、枝晶生长取向与热流方向的偏离角度θ等。
关键词:
定向凝固
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枝晶臂间距
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生长速度
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元胞自动机
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数值模拟
郭颖
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莫韬
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程素华
硅酸盐通报
通过翡翠绿色的色差计算,分析明度差DL、彩度差DC、色调差DH对综合色差DE的贡献.采用CIE L*a*b*均匀色空间中CIE LAB色差公式的计算结果显示,肉眼下66粒质地细腻、绿色均匀的优质翡翠戒面的明度值L*∈(38.50,61.80),属中等偏低的明亮程度;彩度范围C*∈(11.49,44.99),也属中等偏低;色调范围h0∈(134.32,152.96),属略带黄色调的鲜艳绿色.翡翠绿色的平均色差DELAB-AVE=6.10达肉眼可识别级别,平均饱和度差-0.22与平均色调角差0.06均很低,对总色差贡献不大,而明度差DL则表现出了与总色差很高的一致性.得出结论,对中低明度的翡翠绿色色差的最直接贡献者为其明度差,依此建议采用首先以彩度和色调的二元体系作为翡翠绿色定量分级体系,进而依据三维均匀色空间模型CIE L*a*b*,构建以色差为基本单位,明度为Z轴、彩度为X轴和色调为Y轴的三元质量分级体系.
关键词:
色差公式
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翡翠
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绿色
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明度差
