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31.
Haksung Kim Cheol Ho Pyeon Yoshinori Sakurai Tsuyoshi Misawa 《Annals of Nuclear Energy》2011,38(11):2541-2549
Significant axial variation of radial uniformity is observed in Si-ingot neutron transmutation doping in the flux screening method, and leads to non-uniform resistivity distribution for a certain part of Si-ingot. This axial variation of radial uniformity is caused by the installation of a partial neutron screen which decreases the reaction rates differently in the center and surface at the region not surrounded by the partial neutron screen. For the improvement of the specific distribution of radial uniformity in the axial direction, a new concept of axial reflector is introduced to partly change the reaction rate at a certain region of Si-ingot, and neutron irradiation experiments are carried out at the heavy water neutron irradiation facility in the Kyoto University Research Reactor. Based on the experimental and numerical results, the new axial reflector is proved to be effective for improving the axial variation of radial uniformity. 相似文献
32.
Parametric analyses in drying processes of molded ceramics are performed to investigate the influence of heating modes on the formation of drying-induced strain-stress as well as the drying characteristic. The transient three-dimensional problem of strain-stress and heat and moisture transfer in a slab is solved simultaneously by the finite element method. Three modes of hot air, intermittent and internal heating are compared by modeling in the normalized parameters. The tensile and compressive stresses fluctuate, and fall remarkably during the low Biot number period when the slab is heated intermittently. In the internal heating mode, the drying rate is the fastest but stress formation is maintained at the lowest level among the three modes. This effectiveness of the internal heating is investigated experimentally by employing the microwave heating as well. 相似文献
33.
Qiang Dong Nobuhiro Kumada Yoshinori Yonesaki Takahiro Takei Nobukazu Kinomura Dan Wang 《Journal of Materials Science》2010,45(20):5685-5691
Hollow hematite (α-Fe2O3) microspheres with an average diameter of 3-4 μm and a shell thickness of approximate 150 nm was synthesized by a simple
hydrothermal route using FeCl3·6H2O solution and acetic acid without using any templates. The hollow microspheres were composed of α-Fe2O3 nanoparticles with the diameter range from 20 to 40 nm. The effects of reaction parameters such as reaction time, temperature,
concentration of FeCl3·6H2O solution, and initial pH on the morphology of the final products were investigated. A possible formation mechanism of hollow
α-Fe2O3 microspheres was also proposed, where the acetic acid played a role of etching in the formation of hollow structure. 相似文献
34.
Ryuichi Tayama Katsumi Hayashi a Ryo Iwasaki Masana Sasaki Yoshinori Etoh Hiroshi Sakurai 《Nuclear Engineering and Design》2001,210(1-3):239-248
A neutron-scanning device was developed for measuring accurate neutron densities of BWR high burn-up fuels up to 65 GWd tU−1. Characteristic test of this device was done with a 252Cf source and adopted to measure axial distributions of neutron densities of BWR spent fuels with various enrichments (2.0–3.4%), which had been irradiated up to 60 GWd tU−1 at Fukushima Daini Nuclear Power Station Unit 2(2F-2). We found the measured neutron densities were proportional to about fourth power of the corresponding burn-up values. The neutron densities calculated by the ORIGEN2.1 code and various cross section libraries showed good agreements with the measured ones in profile and absolute value except for BWR-UE file mainly based on ENDF/B-IV. The BS240J32 library based on JENDL3.2 was the best among the investigated libraries. 相似文献
35.
36.
Yoshinori Suzuki Takashi Uchida Masataka Wakihara Masao Taniguchi 《Materials Research Bulletin》1981,16(9):1085-1090
Changing the partial pressure of sulfur Ps2 at temperatures of 750° and 950°C, phase equilibria on the Mo-S system by solid-gas reaction were investigated. Hexagonal 2H-MoS2 and monoclinic Mo2S3 phases were identified from the x-ray powder diffraction pattern. The 2H-MoS2 had a slight homogeneity range, i.e. MoS1.978 to MoS2.0 at 950°C, MoS1.983 to MoS2.0 at 750°C. No remarkable variation of lattice parameters for the MoS2 was observed. The composition of the Mo2S3 phase was not stoichiometric MoS1.5 but MoS1.457 at 950°C. At 750°C the composition of the Mo2S3 phase could not be determined since it was quite difficult to establish the equilibrium state between the gas and the condensed phases. This finding agreed well with the result of Morimoto and Kullerud. 相似文献
37.
DNA-DNA hybridization is known as the superior method in the elucidation of relationships between closely related taxa, such as species and strain. For species determination we propose a new DNA-DNA hybridization method: the DNA microarray-based comparative genomic hybridization (CGH) method, using a yeast DNA microarray with approximately 6000 genes. The genome from a yeast strain as a sample strain (Sample) was labelled with Cy3-dye and hybridized to a single DNA microarray, together with the Cy5-labelled genome of S. cerevisiae S288C as a reference strain (Reference). The log2 ratio values [log2[Cy3(Sample)/Cy5(Reference)]: Ratio] of signal intensities of all the gene spots were estimated and divided into the following groups: Ratio < or = -1; -1 < Ratio < 1; 1 < or = Ratio. The hybridization profiles of the genomes of type strains belonging to the genus Saccharomyces were significantly different from that of S. cerevisiae S288C. The Ratio-based grouping allowed us to discriminate between some species from S. cerevisiae more clearly. Furthermore, cluster analysis discriminated between closely related species and strains. Using this method, we were able to not only perform species determination but also to obtain information on alternation in gene copy number of such gene amplifications and deletions with single-gene resolution. These observations indicated that DNA microarray-based CGH is a powerful system for species determination and comparative genome analysis. 相似文献
38.
A new beta-agarase was purified from an agarolytic bacterium, Bacillus sp. MK03. The enzyme was purified 129-fold from the culture supernatant by ammonium sulfate precipitation, anion exchange and gel filtration column chromatographic methods. The purified enzyme appeared as a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Estimation of the molecular mass by SDS-PAGE and gel filtration gave values of 92 kDa and 113 kDa, respectively. The N-terminal amino acid sequence of the enzyme showed no homology to those of other known agarases. The optimum pH and temperature for this enzyme were 7.6 and 40 degrees C, respectively. The predominant hydrolysis product of agarose by this enzyme was neoagarotetraose, indicating the cleavage of beta-1,4 linkage. This enzyme could hydrolyze neoagarohexaose to produce neoagarotetraose and neoagarobiose; it could not hydrolyze these products. The enzyme digested agarose by endo-type hydrolysis. 相似文献
39.
A laser-induced breakdown spectroscopy (LIBS) technique has been applied for detection of unburned carbon in fly ash, and an automated LIBS unit has been developed and applied in a 1000-MW pulverized-coal-fired power plant for real-time measurement, specifically of unburned carbon in fly ash. Good agreement was found between measurement results from the LIBS method and those from the conventional method (Japanese Industrial Standard 8815), with a standard deviation of 0.27%. This result confirms that the measurement of unburned carbon in fly ash by use of LIBS is sufficiently accurate for boiler control. Measurements taken by this apparatus were also integrated into a boiler-control system with the objective of achieving optimal and stable combustion. By control of the rotating speed of a mill rotary separator relative to measured unburned-carbon content, it has been demonstrated that boiler control is possible in an optimized manner by use of the value of the unburned-carbon content of fly ash. 相似文献
40.
Oikawa D Nakanishi T Nakamura Y Takahashi Y Yamamoto T Shiba N Tobisa M Takagi T Iwamoto H Tachibana T Furuse M 《Lipids》2003,38(6):609-614
This study investigated the influence of PUFA on the properties of mouse skin. Mice (3 wk old) were given free access to oils
high in linoleic acid, CLA, or DHA for 4 wk. At the end of the experiment, their skins were compared by both biochemical and
histological methods. No significant differences in lipid and collagen contents were detected among treatments, although the
FA composition in the skin was altered depending upon the FA composition of the supplemented oils. Electron microscopy revealed
that the subcutaneous tissue layers in the CLA and DHA groups were significantly thinner than that in the high linoleic acid
group, whereas no differences in the thickness of dermis layers were observed among the three groups. These results suggest
that skin properties in mice are readily modified by dietary FA sources within 4 wk of dietary oil supplementation. 相似文献