Reconstruction of reflectance spectra using weighted principal component analysis

The weighted principal component analysis technique is employed for reconstruction of reflectance spectra of surface colors from the related tristimulus values. A dynamic eigenvector subspace based on applying certain weights to reflectance data of Munsell color chips has been formed for each particular sample and the color difference value between the target, and Munsell dataset is chosen as a criterion for determination of weighting factors. Implementation of this method enables one to increase the influence of samples which are closer to target on extracted principal eigenvectors and subsequently diminish the effect of those samples which benefit from higher amount of color difference. The performance of the suggested method is evaluated in spectral reflectance reconstruction of three different collections of colored samples by the use of the first three Munsell bases. The resulting spectra show considerable improvements in terms of root mean square error between the actual and reconstructed reflectance curves as well as CIELAB color difference under illuminant A in comparison to those obtained from the standard PCA method. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 360–371, 2008     

T(x) phase diagram of the Cu2Se-Al2Se3 system

Twenty alloys of various compositions in the Cu₂Se-Al₂Se₃ system were prepared and investigated. The T(x) phase diagram of the Cu₂Se-Al₂Se₃ system was obtained from x-ray diffraction, differential thermal analysis, and microstructure investigation for the first time. The homogeneity region of the CuAlSe₂ semiconducting compound was established. Previous articles by this author were presented with the spelling of his name as B.V. Korzun.     

铸铝激光熔融处理后的组织与性能

应用光学和电子显微镜及显微硬度计研究了铸造Al-Si合金经激光表面熔融处理后的组织和性能。指出,组织分熔化区、过度区和基体三层。在熔化区中树枝状先共晶α相的平均宽度由原始组织的20～40μm细化到2～3μm,同时共晶组织也被大大细化。这些变化使显微硬度值由67.4提高至109～115.     

直接斜率波前复原算法的控制效果分析

建立自适应光学系统功率谱抑制函数的概念，分析了采用直接斜率波前复原算法的自适应当光学系统的控制效果，理论分析与６１单元自适应光学系统上的实验结果表明，直接斜率波前复原算法将导致控制效果下降。     

铸造高性能合金的显微组织及耐腐蚀行为

对铸造高性能合金Lewmet55进行了化学成分设计，确定了该合金中镍、铬、钼、铜和硅的含量。采用金相显微镜和X射线衍射相结合的方法，分析了该合金的显微组织，并采用多种腐蚀试验方法研究其耐腐蚀行为。着重研究了不同热处理制度对铸造高性能合金的均匀腐蚀、晶问腐蚀、点蚀和电化学腐蚀性能的影响。试验结果表明，Lewment55合金经1250℃×1．5h水冷固溶处理后，在高温浓硫酸介质中具有良好的耐蚀性，以及较好的抗晶间腐蚀、点蚀和电化学腐蚀性能。     

Microstructure and creep of eutectic indium/tin on copper and nickel substrates

The behavior during creep in shear of eutectic indium-tin joints on copper and nickel substrates was examined in order to determine the effect of creep deformation on the microstructure of the alloy. Primary creep was absent in all the samples tested. The stress exponent at 20° C was much higher for samples on nickel than for those on copper, indicating a different creep deformation mechanism. Also, the microstructure within the indium-tin joints differed significantly with a change of substrate. Samples with a nickel substrate showed a colony microstructure that was not observed in those with a copper substrate. Thus, eutectic morphology is important in determining deformation mechanism during creep. The microstructure within the joints in tested and untested regions of the samples was effectively the same. This is quite distinct from the behavior of eutectic lead-tin observed in previous work. Lead-tin formed a recrystallized band of material along a region of concentrated shear deformation. While the deformation pattern in the indium-tin samples appeared to be the same as for lead-tin, the microstructural changes did not occur. This implies that the behavior observed in lead-tin is not universal to eutectic alloys.     

Effect of the particle size ratio on the conductivity of conductor-insulator powder composites: Numerical simulation

A theoretical method for determining the percolation limit and effective conductivity of composites based on polydisperse mixtures of insulator and conductor powders is proposed. The effect of the particle size ratio between the insulator and conductor on the percolation limit and effective conductivity is studied. Numerical simulation of the microstructure, effective properties, and percolation limit in composites is discussed. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 1–2(453), pp. 31–40, 2007.     

Combined-Stage Sintering Model

By focusing on the similarities between the three stages of sintering, a single equation is derived that quantifies sintering as a continuous process from beginning to end. The microstructure is characterized by two separate parameters representing geometry and scale. The dimensionless geometry parameter, denoted T, comprises five scaling factors that relate specific microstructural featuers (e.g., surface curvature) to the scale (grain diameter). Calculations of T from experimental data show (a) agreement with computer simulations of initial-stage sintering, (b) the effect of surface diffusion on T, and (c) changes in T with microstructural evolution during sintering. Application of the model to the design of firing schedules and the study of microstructural geometry effects on sintering is discussed.     

添加尖晶石对氧化锌压敏电阻性能的影响

通过添加尖晶石（Ｚｎ７Ｓｂ２Ｏ（１２））改性研制出电位梯度为１００Ｖ／ｍｍ左右，压敏电压在８２～１５０Ｖ，通流容量可达１６００Ａ／ｃｍ２，漏电流＜２μＡ系列压敏电阻器，从而满足了国内电话交换机行业对８２Ｖ、１００Ｖ、１２０Ｖ、１５０Ｖ压敏电阻器的电性能要求。从工艺的角度解释了尖晶石对氧化锌瓷晶粒的作用原理，并分析了尖晶石的微观结构及粒度对瓷片电性能的影响。     

激光辐照40Cr钢组织结构的穆斯堡尔谱分析

４０Ｃｒ钢试样经不同热处理后在空气中用ＣＯ２连续激光束进行辐照，以穆斯堡尔谱学研究试样在辐照后的组织结构变化。试验结果表明，调质预处理后再进行激光辐照的试样，不仅残作产奥氏体含量较低，而且其中碳的含量最低。