Graded evolution of anisotropic microstructure during sintering from crystal-oriented powder compact

Anisotropic sintering, including shrinkage and grain growth, was examined for c-axis-oriented (Sr,Ca)₂NaNb₅O₁₅ (SCNN) ceramics, which were prepared by colloidal processing under a magnetic field. In the c-axis-oriented SCNN powder compact, shrinkage and grain growth along the c-axis were higher than those along the a-axis. The anisotropic microstructural development was clearly associated with anisotropic sintering shrinkage. X-ray diffraction, scanning electron microscopy, and energy back scattering diffraction showed that the grain growth of oriented particles by including random grains contribute to the development of the oriented microstructure. Finally, the highly crystal-oriented SCNN ceramics with a densified microstructure were obtained through anisotropic sintering. These results clearly showed the potential to develop a well-defined anisotropic microstructure during sintering by designing and controlling the particle packing structure in a powder compact.     

Vapor absorption by LiBr aqueous solution in vertical smooth tubes

Heat and mass transfer in a falling film vertical in-tube absorber was studied experimentally with LiBr aqueous solution. The presented results include the effect of solution flow rate, solution subcooling and cooling water temperature on the absorption in a smooth copper tube 16.05 mm I.D. and 400 mm long. The experimental data in the previous report for a 1200-mm-long tube was also re-examined and compared. It was demonstrated by the observation of the flow in the tube that the break down of the liquid film into rivulets leads to deterioration of heat and mass transfer at lower film Reynolds number or in longer tubes. An attempt to evaluate physically acceptable heat and mass transfer coefficients that are defined with estimated temperature and concentration at the vapor–liquid interface was also presented.     

Preparation of pyrochlores. A1−xHxTaO3·nH2O (A=Na,K)

Pyrochlores of A_1?xH_xTaO₃·nH₂O (A=Na,K) were prepared under the hydrothermal conditions. The values of x for these compounds were increased from 0.3 to 0.5 for A=Na and from 0.2 to 0.5 for A=K by treatment with the distilled water. The compounds with x<0.5 were decomposed to a mixture of NaTaO₃ and Na₂Ta₄O₁₁ for A=Na, or to a mixture of KTaO₃ and a tetragonal tungsten bronze phase, and those with x=0.5 to a single phase of A₂Ta₄O₁₁ at elevated temperatures. Below the decomposition temperatures, defect pyrochlores with oxygen vacancies, $\text{A}{}_{\mathrm{<mtext>1?</mtext><mtext>x</mtext>}}\text{TaO}{}_{\mathrm{<mtext>3?</mtext><mtext>x</mtext><mtext>2</mtext>}}$, were produced. They were hygroscopic, and in the case of A=K and x=0.5 the original phase was recovered by leaving in air for several hours.     

Interferon-gamma and interleukin-10 inhibit antigen presentation by Langerhans cells for T helper type 1 cells by suppressing their CD80 (B7-1) expression

CD80(B7-1) and CD86(B7-2) co-stimulatory molecules have been reported to activate Th1/Th2 development pathways differentially. It is well known that Langerhans cells (LC), potent antigen-presenting dendritic cells in the epidermis, express several co-stimulatory molecules and that this expression is modulated by several cytokines. Based on the recently reported effect of interferon (IFN)-gamma and interleukin (IL-)-10 on the expression of CD80 and CD86 by LC, we examined the effects of these cytokines on the expression of CD54 (intercellular adhesion molecule-1) and CD40 in addition to CD80 and CD86 on LC, and correlated the expression of each co-stimulatory molecule with antigen presentation for a Th1 clone by cultured LC (cLC) treated with these cytokines. LC cultured for 72 h significantly up-regulated MHC class II antigen expression and all the co-stimulatory molecules were examined. As previously reported, IL-10 or IFN-gamma inhibited the up-regulation of CD80 expression. Granulocyte/macrophage-colony-stimulating factor (GM-CSF) partially restored the suppression of CD80 expression induced by IFN-gamma on cultured LC, while it had virtually no effect on the inhibition induced by IL-10. Antigen presentation for the myoglobin-specific syngeneic Th1 clone by cLC, which were pre-incubated with these cytokines, correlated well with their CD80 expression. In addition, among the antibodies for CD80, CD86, CD28 or CD40, the suppression of the Th1 clone stimulation by LC was found to occur only with anti-CD80 and anti-CD28 antibodies. Finally, we studied the effects of IFN-gamma and IL-10 on GM-CSF production by epidermal keratinocytes (KC). We could show that only IFN-gamma, but not IL-10, suppressed GM-CSF production by KC. These findings suggest that both IFN-gamma and IL-10 suppress antigen presentation by LC for Th1 cells by suppressing their CD80 expression. The inhibitory effect of IFN-gamma on CD80 expression on LC appears to be partially mediated through the suppression of GM-CSF production by KC.     

One-stage anterior and posterior correction of severe kyphosis of the cervical spine in neurofibromatosis. A case report

A case is presented of a 29-year-old woman with neurofibromatosis, who had a 100 degrees dystrophic kyphosis of the cervical spine and was successfully treated by a one-stage anterior and posterior correction. Anterior distractive and posterior compressive corrections were simultaneously applied keeping the posterior longitudinal ligament intact. The kyphosis was corrected to 42 degrees. Safety and better results of the one-stage correction of kyphosis is based on a concept of shortening the spinal canal.     

66/77-kV C-GIS using composite insulation in SF6 gas

A second-generation model of cubicletype gas-insulated switchgear (C-GIS) with composite insulation incorporating SF₆ gas has been developed. The design does not require a gas process in field assembly; it has high reliability and its installation is more rapid; and a further reduction in size is achieved. The design principles are described in detail.     

FDTD analysis of switching characteristics in magnetooptic functional devices using magnetostatic surface waves

Collinear magnetooptic interaction with magnetostatic surface waves (MSSW) can be used for wavelength‐selective switches, wavelength filters, and frequency shifters in wavelength‐division‐multiplexed (WDM) photonic networks and optical processing systems. The switching efficiency can be improved with a multilayer waveguide structure. To investigate the dynamic switching characteristics, the FDTD method was employed. The mode conversion between TE and TM mode was successfully demonstrated with FDTD simulation. The filtering characteristics were also evaluated. The FDTD results were compared with the result from the coupled mode theory, and good agreement was obtained. Switching of an optical pulse was also demonstrated by the FDTD method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(1): 40–47, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20501