Scanning electron microscopic structure of the prismatic layer in the Bivalvia

The shell structure of the Bivalvia has been observed with the use of optical and electron microscopes since the early 1900’s. The prismatic structure is one of the more attractive shell structures in bivalved mollusks. This structure is composed of the aggregation of polygonal prisms arranged densely. Each prism is made of small calcite crystallites arranged perpendicular to a growth shell surface. Organic materials, named organic sheaths, accumulate around prisms and stain well with heamatoxylin-eosin.The Bivalvia, which make prismatic structures, are divided into two groups. One group has the inner shell layer made up of a nacreous structure, and the other has the inner shell layer made up of a foliated structure. The aragonite prismatic layer and the prismatic layer are closely related to each other, as is the aragonite prismatic layer to the composite prismatic one.     

Enthalpy of Denaturation and Surface Functional Properties of Heated Egg White Proteins in the Dry State

The enthalpy of denaturation (ΔH) and surface properties of proteins were related to elucidate the mechanisms of foaming and emulsifying properties by using various heated egg white proteins in the dry state. Foaming and emulsifying properties of all sample proteins were greatly increased with a decrease in the enthalpy of denaturation as determined by differential scanning calorimetry analysis. In plots, foaming and emulsifying properties correlated linearly with ΔH values for various dry-heated egg white proteins. Thus, the enthalpy of denaturation of proteins seemed to be a significant structural factor governing surface functional properties.     

Electronic structure analysis of magnetic properties of Fe16N2

Summary The magnetic properties of Fe₁₆N₂, bcc iron and bct iron were studied using the linear muffin tin orbital method in combination with the atomic sphere approximation (LMTO-ASA). The following results were obtained: The magnetovolume effect is the most important for the large magnetic moment of Fe₁₆N₂. The magnetic moment of iron increases with the distance from the nitrogen. The nitrogen atom plays a role in expanding the lattice. The effect of local lattice relaxation of the iron atoms that are first- and second-nearest neighbors to a nitrogen atom was examined.     

Growth of whiskered ZrO2 crystals by hydrothermal decomposition of zirconium oxide sulphate pseudo-crystals

Several kinds of metastable compounds, pseudo zirconium oxide sulphates (PZOS) with a chemical composition of Zr₃O₅SO₄·nH₂O, were previously synthesized by the thermal hydrolysis of solutions containing zirconium sulphate at 200 or 240°C. The obtained PZOS samples were again hydrothermally treated in different sulphuric acid solutions (<1.0 mol l^-1) at 240°C, and their hydrothermal decomposition behaviour was investigated by TEM observation. The PZOS samples mostly crystallized to plate-like zirconium oxide sulphate (ZOS) in the concentrated sulphuric acid solution (>0.5 mol l^-1), but long-whiskered monoclinic ZrO₂ crystals grew with decomposition of the PZOS samples obtained from the starting mixtures with added Zr(OH)₄ when rapidly heated to the hydrothermal treatment temperatures. It was found that many ultrafine monoclinic ZrO2 crystals were simultaneously formed during the hydrothermal preparation of the PZOS samples, and during the following hydrothermal decomposition of the PZOS samples, the whiskered crystals of monoclinic ZrO2 grew with the consumption of PZOS from the coexisting ultrafine monoclinic ZrO2 particles which act as seed crystals. This revised version was published online in November 2006 with corrections to the Cover Date.     

Characterization of Cu(InxGa1−x)2Se3.5 thin films prepared by rf sputtering

Cu(In_xGa_1−x)₂Se_3.5 thin films were fabricated by rf sputtering from CuIn_xGa_1−xSe₂ and Na mixture target by controlling the mixture ratio. X-ray diffraction analyses show that the structure of Cu(In_xGa_1−x)₂Se_3.5, thin films is different from chalcopyrite structure: especially, CuIn₂Se_3.5 thin films have a defect chalcopyrite structure. The lattice parameters for Cu(In_xGa_1−x)₂Se_3.5 thin film are slightly smaller than those for CuIn_xGa_1−xSe₂ thin film and linearly decreased with increasing Ga content. The optical absorption coefficients for Cu(In_xGa_1−x)₂Se_3.5, thin films exceed 2 × 10⁴ cm⁻¹ in energy region above the fundamental band edge. The band gap for Cu(In_xGa_1−x)₂Se_3.5 thin films is larger than that for CuIn.Ga_1−x2Se₂ with the same Ga content and increased with increasing Ga content.     

Synchrotron X-Ray Study of the Crystal Structure and Hydrothermal Degradation of Yttria-Stabilized Tetragonal Zirconia Polycrystal

Structural study with synchrotron X-ray diffractometry was made on phase separation phenomena in 2, 3, and 4 mol% Y₂O₃-stabilized tetragonal ZrO₂ polycrystal (abbreviated as 2, 3, and 4Y-TZP, respectively). The sintered body of 3Y and 4Y-TZP underwent phase separation into high and low yttrium regions as sintering temperature increased, and the tetragonal phase was assigned to both regions. The sintering body is less separated, and a large monoclinic phase was detected in 2Y-TZP. Analysis of aging kinetics of tetragonal- to monoclinic-phase transition showed that the fraction of the transformable phase agreed with that of the low yttrium region.     

Optimized Logarithmic Roller Crowning Design of Cylindrical Roller Bearings and Its Experimental Demonstration

A logarithmic profile is essentially an optimal geometry for rolling machine elements such as bearing rollers and raceways. Under most conditions of loading, it yields lower stresses to give longer endurance. Lundberg first suggested the basic profile, and some researchers followed him by modifying it to satisfy engineering requirements. In this article, the authors propose a mathematical optimization method for logarithmic profiles in roller bearing applications. Moreover, rolling contact fatigue life tests are carried out to make a comparison among logarithmically crowned, standard partially crowned, and modified partially crowned rollers. Results show that the logarithmically crowned rollers are beyond the modified partially crowned rollers in fatigue life, especially in poor lubrication conditions, although the logarithmic rollers require less workload to process the crowning.     

3D晶体取向测试技术在铝合金晶粒变形分析中的应用

非均匀变形在材料工程领域是一个有趣的问题。同步辐射成像技术通过跟踪多晶体铝合金的显微组织的特性,提供了局部应变的3D分布图。为了更加深入地分析非均匀的过程,开发了三维X射线衍射分析技术。它利用跟踪晶界获得的信息（GBT）,描述了三维空间中新的晶体取向测试技术。     

EXTRACTION OF PALLADIUM(II) AND PLATINUM(IV) AS CHLOROCOMPLEX ACIDS INTO BASIC ORGANIC SOLVENTS

Solvent extraction of platinum(IV) and palladium(II) with tri-n-octylamine(TOA) in o-xylene from 4.0M (Na,H)(Cl, HSO₄) has been investigated at 298K in order to compare with similar extraction by trioctylphosphine oxide(TOPO). The dependence of the distribution ratio of platinum(IV) and pal 1adium(II) on TOA, hydrogen ion and chloride ion concentrations suggests the dominant extracted species of these metals would be 2:1 for proto-nated amine : chlorocomplex anion and the extraction should be essentially anion exchange reaction. The extraction constants (Kex = D[H⁺(T0A)C1 ] ²[C1 ]²), were evaluated as 10^6-3 and 10^5.8 for platinum(IV) and pal ladium(II), respectively. The anion exchange with protonated TOPO salt represented by H(T0P0)₂ ⁺C1  is less than that with protonated TOA salt by a factor of one order.