Suppression of creep cavitation in precipitation-hardened austenitic stainless steel to enhance creep rupture strength

Extensive creep cavitation in Ti, Nb and Cu containing precipitation hardened austenitic steels was found to limit the usefulness of deformation resistance to increase long-term creep rupture strength. The steels were microalloyed with boron and cerium that resulted in increase in creep rupture strength and ductility of the steels significantly. Grain boundary sliding and creep cavity nucleation and growth in the steels were suppressed greatly on microalloying. Auger spectroscopic analysis revealed the segregation of boron instead of sulfur on cavity surface and the absence of sulfur contamination of grain boundary upon the microalloying. Suppression of creep cavitation through the control of trace elements segregation along with the precipitation hardening increased the creep rupture strength of austenitic stainless steels.     

The viscoplasticity theory applied to the inelastic analysis at elevated temperatures

Monotonic and cyclic loading tests on strain rate changes are conducted on — 1Mo steel at 600°C. The examination of the tensile stress-strain response suggests that the viscosity function which characterizes the rate-dependency in the viscosity theory used previously at room temperature should not only depend on the overstress but also on the strain. A new extended viscosity control function is introduced to represent such strain dependency.The material constants of this modified viscoplasticity model are determined at temperatures of 25°C to 600°C and the model is applied to deformation tests on — 1Mo steel carried out under time-varying temperature conditions and other conditions.The extended viscoplasticity theory is shown to reproduce such various experimentally observed stress-strain behavior at elevated temperatures.     

Effects of filtration through activated carbons on peroxide,thiobarbituric acid and carbonyl values of autoxidized soybean oil

Effects of filtration bleaching on peroxide value (PV), thiobarbituric acid value (TAV) and carbonyl value (CV) of autoxidized soybean oil were investigated by using twenty-three kinds of activated carbon in order to improve oil quality. From the decreases in PV, TAV and CV and from the physical and chemical properties of activated carbons, it was suggested that hydroperoxides, aldehydes and ketones were adsorbed on the acid sites distributed over the surface or within the pores of the activated carbons while the autoxidized soybean oil flowed through the packed column. The residual tocopherols in autoxidized soybean oil and treated soybean oil were determined during storage. The decrease in oxidative stability of treated soybean oil seemed to be caused by elimination ofα-,β-andγ-tocopherols.δ-Tocopherol was chemically more stable thanα-,β- andγ-tocopherols in autoxidized soybean oil.     

Characterization of crystalline low temperature GaAs layers annealed from an amorphous phase

The results from an in-depth characterization of as-grown and annealed low-temperature GaAs layers deposited at less than 260°C are presented. The layers, amorphous as grown, became crystalline after annealing. The crystallization was documented by several characterization techniques including photoreflectance, Raman spectroscopy, photoluminescence, transmission electron microscopy, and double-crystal x-ray diffraction. The n-type conductivity of the annealed films was exploited for the construction of a diode structure.     

Apple polyphenols influence cholesterol metabolism in healthy subjects with relatively high body mass index

We performed a randomized double-blind, placebo-controlled study on moderately obese male and female subjects (71 subjects) with a body mass index ranging from 23 to 30 to evaluate the efficacy of 12-week intake of polyphenols extracted from apples and hop bract (600 mg/day). We confirmed that 12-week ingestion of polyphenol-containing capsules significantly decreased total cholesterol and LDL-cholesterol levels. The effects of the apple polyphenol-containing capsules were more marked than those of the hop bract polyphenol-containing capsules. The visceral fat area and the level of adiponectin in the group administered apple polyphenols improved in comparison with the control group. Blood and physical examinations revealed on clinical problems, and no adverse reactions were observed during the ingestion period. These results demonstrate that apple polyphenols regulate fat metabolism in healthy subjects with relatively high body mass index.     

Evaluation of low-level asbestos exposure by transbronchial lung biopsy with analytical electron microscopy

To improve diagnostic sensitivity for detecting low-level asbestos exposure (AEx) in patients, a new method was developed using an analytical transmission electron microscope (ATEM) for specimens of transbronchial lung biopsy (TBLB). The TBLB specimens from 28 patients were examined and the results were: 1) In cases with long-term AEx, the present method detected a large amount of asbestos fibers (AF) as well as asbestos bodies (AB) showing a good agreement with the results of light microscope (LM) which detected definite amounts of ferruginous bodies (FB). 2) In cases with short-term or suspected AEx, the LM failed to detect FB in some cases, but an appreciable amount of AF was detected using the present method, and AEx was disclosed through a second close interview. 3) Neither AB nor AF were detected in most of the cases without any dust exposure. Although small amounts of chrysotile fibers were observed in some cases, this might simply reflect the exposure level of urban dwellers. These results show that the ATEM applied to the TBLB specimens promises to confirm low-level AEx in such small specimens even if the patients were unaware of their past AEx.     

InAlAs/InGaAs heterojunction bipolar transistors with AlAs etch-stop layer

A seven monolayer AlAs layer was used as an etch stop at the emitter-base heterojunction of an Npn In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As HBT. The etch-stop HBTs displayed higher DC gain and similar microwave performance when compared to devices without the AlAs layer.<>     

Protein engineering of diphtheria-toxin-related interleukin-2 fusion toxins to increase cytotoxic potency for high-affinity IL-2-receptor-bearing target cells

We have used site-directed insertion and point mutagenesis inan attempt to increase the cytotoxic potency and receptor-bindingaffinity of the diphtheria-toxin-related interleukin-2 (IL-2)fusion toxins. Previous studies have demonstrated that boththe DAB₄₈₆-IL-Z and DAB₃₈₉-IL-2 forms of the fusion toxin consistof three functional domains: the N-tenninal fragment-A-assodatedADP-ribosyltransferase, the hydrophobk-membrane-associatingdomains, and the C-terminal receptor-binding domain of humanIL-2. By insertion mutagenesis we have increased the apparentflexibility of the polypeptide chain between the membraneassociatingdomains and the receptor-binding domain of this fusion toxin.In comparison to DAB₄₈₆-IL-2, the cytotoxic potency of the insertionmutants was increased by 17-fold for high-affinity IL-2-receptor-bearingcell lines in vitro. Moreover, competitive displacement experimentsusing [¹²⁵I]rIL-2 demonstrate that the increase in cytotoxicpotency correlates with an increase in receptor-binding affinityfor both the high and intermediate forms of the IL-2 receptor.     

Non-reciprocity and topology in optics: one-way road for light via surface magnon polariton

We show how non-reciprocity and topology are used to construct an optical one-way waveguide in the Voigt geometry. First, we present a traditional approach of the one-way waveguide of light using surface polaritons under a static magnetic field. Second, we explain a recent discovery of a topological approach using photonic crystals with the magneto-optical coupling. Third, we present a combination of the two approaches, toward a broadband one-way waveguide in the microwave range.