XAFS Analysis for Niobium Carbide Particle Growth on Silica Support During Preparation Process

SiO₂-supported NbC catalysts were prepared by using temperature-programmed reactions (TPR). XAFS analysis confirmed that Nb₂O₅ was reduced to NbO₂ in the first TPR stage and converted into NbC in the second TPR stage. Nb particles grew only in the second TPR stage. Formation of highly dispersed NbC particles on SiO₂ surfaces was achieved.     

Improvement of ageing properties of rubber films prepared from radiation-vulcanized natural rubber latex

Radiation-vulcanization of natural rubber latex (NRL) with n-butyl acrylate gives a higher tensile strength for films obtained after casting. The ageing properties of radiation-vulcanized natural rubber in the presence of various antioxidants have been investigated. In order to find out suitable antioxidants for radiation-vulcanized natural rubber latex (RVNRL) films, extraction of the gel fraction was carried out in xylene with 1 wt.-% antioxidant and air bubbling. Antioxidants which give less reduction in gel fraction due to oxidative degradation during extraction are effective for ageing tests of RVNRL films. It was found that tris(nonylated phenyl) phosphite (Nonflex TNP) and 2,5-di-tert-amylhydroquinone (Antage DAH), among 12 different antioxidants tested, were the most effective antioxidants for RVNRL films.     

Conditions for growth of AlN single crystals in Al–Sn flux

In this study, we investigated the Al–Sn flux system and its growth conditions to obtain AlN single crystals. AlN single crystals of a size of 50 μm were successfully grown using an Al–Sn melt under nitrogen gas pressure. The growable region of the AlN crystals was established using a pressure‐temperature diagram. The required nitrogen gas pressure for the growth of the AlN crystals was found to decrease with increasing temperature, and AlN was grown at 0.1 MPa nitrogen pressure above 1300°C. By investigating the AlN yield with various Al concentrations, we confirmed that the Al component in the Al–Sn melt facilitated nitrogen dissolution. Finally, scanning electron microscopy analysis showed that the obtained AlN particles showed good morphology.     

An improved method of phosphorus analysis in sea water

A reagent for the determination of phosphorus in sea water which contains Mo(VI) plus Mo(V) may be easily prepared by the reduction of Mo(VI) with metallic zinc in acid medium. This reagent is stable in the air for several months, and the development of the molybdenum blue colour is complete in 20 min at about 100°C; the colour is stable for at least a few months. The salt error is approximately 5 per cent with sea water of chlorinity 19 per milli. The interference due to either arsenate or silicate at their concentrations in sea water is negligible.     

沉积软岩强度和变形特征的研究综述

The strength and deformation characteristics of sedimentary soft rock evaluated in relation to several large-scale researc and construction projects in Japan are reviewed.The elastic stiffiness at small non-linearity due to strain and pressure level,and viscous properties are described.The elastic stiffness from triaxial tests using high-quality core samples while measuring stresses and strains accurately is basically the same as the corresponding value from field shear wave velocity.It is necessary to take into account the dependency or stiffness on shear and pressure level,which could be evaluated by relevant laboratory stress-strain tests while referring to results trom relevant field loading tests.Loading rate effects due to the material viscous properties could be simulated by a non-linear three-component model.     

Variant Selection in Grain Boundary Nucleation of Upper Bainite

The crystallography of bainitic ferrite nucleated at austenite grain boundaries was studied in an Fe-9Ni-0.15C (mass pct) alloy. The relationship between bainitic ferrite orientations (variants) and grain boundary characters, i.e., misorientation and boundary orientation, was examined by electron backscatter diffraction analysis in scanning electron microscopy and serial sectioning observation. Bainitic ferrite holds nearly the Kurdjumov–Sachs (K-S) orientation relationship with respect to the austenite grain into which it grows. At the beginning of transformation, the variants of bainitic ferrite are severely restricted by the following two rules, both advantageous in terms of interfacial energy: (1) smaller misorientation from the K-S relationship with respect to the opposite austenite grain and (2) elimination of the larger grain boundary area by the nucleation of bainitic ferrite. As the transformation proceeds, variant selection establishing plastic accommodation of transformation strain to a larger extent becomes important. Those kinds of variant selection result in formation of coarse blocks for small undercooling. This article is based on a presentation given in the symposium entitled “Solid-State Nucleation and Critical Nuclei during First Order Diffusional Phase Transformations,” which occurred October 15–19, 2006 during the MS&T meeting in Cincinnati, Ohio under the auspices of the TMS/ASMI Phase Transformations Committee.

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Integration of multianalyte sensing functions on a capillary-assembled microchip: simultaneous determination of ion concentrations and enzymatic activities by a "drop-and-sip" technique

A general and simple implementation of simultaneous multiparametric sensing in a single microchip is presented by using a capillary-assembled microchip (CAs-CHIP) integrated with the plural different reagent-release capillaries (RRCs), acting as various biochemical sensors. A novel "drop-and-sip" technique of fluid handling is performed with a microliter droplet of a model sample solution containing proteases (trypsin, chymotrypsin, thrombin, elastase) and divalent cations (Ca2+, Zn2+, Mg2+) that passes through the microchannel with the aid of a micropipette as a vacuum pump, concurrently filling each RRC via capillary force. To avert the evaporation of the nanoliter sample volume in each capillary, PDMS oil is dropped on the outlet hole of the CAs-CHIP exploiting the capillary force that results in spontaneous sealing of all the RRCs. In addition, this high-speed sample introduction alleviates the possibility of protein adsorption and capillary cross-contamination, allowing a reliable and multianalyte determination of a sample containing many different proteases and divalent cations by using the fluorescence image analysis. Presented results suggested the possible application of this microchip in the field of drug discovery and systems biology.     

Phase Equilibria and Phase Transition of the Ni–Fe–Ga Ferromagnetic Shape Memory Alloy System

Phase equilibria and martensitic and magnetic transitions of the β (B2 and L2₁) phase in the Ni–Fe–Ga system were investigated. The b phase was found to be in equilibrium with the γ (A1 structure) or γ′ (L1₂ structure) phase. The Curie temperature, T _c , equilibrium temperature, T _o 5 (Ms + Af)/2, martensitic transition starting temperature, M _s , and reverse transition finishing temperature, Af , of the β single–phase alloys were sensitive to the Fe and Ga compositions. The Fe substitution for Ni decreased and increased the T _o and T _c , respectively. The Ga substitution for Ni or Fe decreased both the T _o and T _c . The entropy change accompanying the reverse martensitic transition showed compositional dependence due to the magnetic contribution. The saturation magnetization I _s of the Ni–Fe–Ga system showed a strong dependence on the magnetic valence Z _M . The Is values of the Ni–Fe–Ga alloys annealed at 1023 K showed the same Z _m dependence as other ferromagnetic shape memory alloy (FSMA) systems. This article is based on a presentation made in the symposium entitled "Phase Transformations in Magnetic Materials," which occurred during the TMS Annual Meeting, March 12-16, 2006, in San Antonio, Texas, under the auspices of the Joint TMS–MPMD and ASMI–MSCTS Phase Transformations Committee.     

Osteoblast behavior on TiO2 microgrooves prepared by soft-lithography and sol–gel methods

This study focused on the effects of microgrooved TiO₂ surfaces on osteoblast behavior. Microgrooved TiO₂ surfaces with different widths (12 μm and 40 μm) and flat surfaces were fabricated on glass substrates based on the combination of a sol–gel technique and soft-lithography. Osteoblasts (MC3T3-E1) were cultured on the as-prepared microgrooved and flat TiO₂ surfaces. Optical microscopy and scanning electron microscopy were used to analyze the adherent cell behavior by examining the cell morphology. Orientation angle analysis indicated that the cells tended to align along the microgrooves. This tendency was stronger on the microgrooves with smaller widths and became weak with increasing width. Alamar Blue assay indicated that the microgrooves restricted cell proliferation and the alkaline phosphatase assay revealed that the microgrooves limited the differentiation rate. This restriction increased with decreasing microgroove width. The surface energy of the TiO₂ surfaces was size-dependent and followed the order γ _12 μm < γ _40 μm < γ _{flat surfaces}. Osteoblast proliferation and differentiation on the surface with high surface energy exhibited high proliferation and differentiation rates. These results indicated that surface energy appeared to be a dominant factor for cell activity. Thus, surface energy would be a valuable index for the cell compatibility of a micropatterned surface.     

多乙烯基单体对溴化丁基胶电子束交联的敏化效应

观察到溴化丁基胶(BIIR)在加速器产生的电子束辐照下可发生交联反应,测得其凝胶化剂量为12 kGy。在剂量较低时辐照产物的凝胶含量与交联密度均随剂量增加而提高,但在80 kGy后则随剂量增加而呈下降趋势。试验了5种多乙烯基单体以敏化BIIR的交联反应,从而避免高剂量下的降解现象。结果表明TMPT(三甲基丙烯酸三羟甲基丙烷酯)是有效的敏化剂,配有TMPT的BIIR交联产物其拉伸强度随TMPT用量增大而明显提高。