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A variety of diffusivities in Ge-Si alloys available in the literature were critically reviewed. On the basis of the critically reviewed literature data, the diffusion parameters for self diffusivities and impurity diffusivities in diamond Ge-Si alloys were determined by considering the diffusion mechanism. A phenomenological treatment of the diffusivities in Ge-Si alloys were conducted. The finally obtained atomic mobilities can reproduce most of the diffusivities in diamond Ge-Si alloys as well as the concentration profiles of Ge-Si binary diffusion couples. In addition, the Manning modification on Darken Equation in diamond structure was also tested by using the presently obtained atomic mobilities.

The Sc-Zn system has been critically reviewed and assessed by means of CALPHAD (CALculation of PHAse Diagram) approach. By means of first-principles calculation, the enthalpies of formation at 0 K for the ScZn, ScZn2, Sc17Zn58, Sc3Zn17 and ScZn12 have been computed with the desire to assist thermodynamic modeling. A set of self-consistent thermodynamic parameters for the Sc-Zn system is then obtained. The calculated phase diagram and thermodynamic properties agree well with the experimental data and first-principles calculations, respectively.

Based on the critical review of all the available experimental data in the literature, 8 key alloys were prepared by arc melting to investigate the phase equilibria in the Zr-Y system, These alloys, which were annealed at 5 different temperatures (800°C, 1000°C, 1100°C, 1120°C, 1160°C), were analyzed by means of X-ray diffraction, differential scanning calorimetry, optical microscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The results showed that a peritectoid reaction (βZr) + (αY) = (αZr) occurs at 886°C ± 5°C, and an eutectic reaction L = (βZr) + (αY) occurs at 1313°C ± 5°C. Taking into account the experimental data obtained both from this work and the literature, the Zr-Y system was thermodynamically modeled. The previously reported temperature for the peritectic reaction of (βY) + L = (αY) at about 1490 °C is supported by our thermodynamic calculation. Comparison between the calculated and measured phase diagrams shows that the thermodynamic calculation can well account for the experimental data.

Background Dyschromatosis symmetrica hereditaria (DSH) is an autosomal dominant pigmentary genodermatosis characterized by hyperpigmented and hypopigmented macules on the extremities, which has recently been mapped to an 11·6-cM interval on chromosome 1q11-21. So far, most cases of DSH have been reported in Japan and dermatologists around the world might think this disorder mainly occurs in Japan. In fact, there are 17 DSH families including 136 cases reported in China since 1980, but most of them are described in Chinese. Objectives To refine the previously mapped region that facilitates the identification of the DSH gene and to delineate the clinical and genetic features of Chinese DSH cases by a literature review of 136 cases reported in China. Methods We performed genotyping and linkage analysis using polymorphic microsatellite markers at 1q11-22 in two Chinese DSH families, and reviewed all of the DSH cases reported in China since 1980. Results A cumulative maximum two-point lod score of 3·68 was produced with marker DIS506 at a recombination frequency of θ = 0·00 in these two families. Haplotype analysis refined the DSH locus to a 9·4-cM interval flanked by D1S2343 and D1S2635. The genetic and clinical features of Chinese cases with DSH were summarized. In some Chinese cases, hyperpigmented and hypopigmented macules were scattered on the neck and chest, but among Japanese patients there were no similar skin lesions to be reported on these sites. Conclusions This study confirms linkage of DSH to a previously mapped region and refines the DSH gene to a 9·4-cM interval at 1q21-22. Likewise, the literature review indicates that DSH is not an uncommon disorder in China and the differences in the distribution of skin lesions could be related to race and environment. [ABSTRACT FROM AUTHOR]