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21.
Takeshi Takeda Kazuhiko Kunitomi Minoru Ohkubo Toshiji Saito 《Nuclear Engineering and Design》1998,185(2-3)
Experimental study was made to confirm the validity of new designs of the auxiliary cooling system for the high temperature engineering test reactor (HTTR). First, it is necessary to vent residence air in outlet side of water chamber of the auxiliary heat exchanger for the HTTR. Accordingly, we have proposed to mount a proper bend duct in the outlet side of the water chamber. Air vent is done by difference between pressures at both ends of the bend duct caused by the forced water circulation using the water pumps. From flow tests, it was confirmed that it is capable of venting the air through the bend duct by circulating the water in maximum capacity of the water pumps. Second, it is essential to prevent seizure and excessive wear of the liner slides of the auxiliary concentric hot gas duct for the HTTR at a service temperature of 950°C. Therefore, we have put forward to coat titanium nitride (TiN) on the surface of the liner slides made of nickel-based superalloy Hastelloy XR using the thermochemical vapor deposition method. As a result of seizure and wear tests, it was confirmed that the TiN coating film of 3 μm on the surface of Hastelloy XR is sufficient. 相似文献
22.
Boron removal by titanium addition in solidification refining of silicon with Si-Al melt 总被引:4,自引:0,他引:4
Takeshi Yoshikawa Kentaro Arimura Kazuki Morita 《Metallurgical and Materials Transactions B》2005,36(6):837-842
In order to effectively remove B from Si for its use in solar cells, a process involving B removal by solidification refining
of Si using a Si-Al melt with Ti addition was investigated. For clarifying the effect of Ti addition on B removal from the
Si-Al melt, TiB2 solubilities in Si-64.6 at. pct Al melt at 1173 K and Si-60.0 at. pct Al melt at 1273 K were determined by measuring the
equilibrium concentrations of B and Ti in the presence of TiB2 precipitates. The small solubilities of TiB2 in the Si-Al melt indicate the effective removal of B from the Si-Al melt by Ti addition. Further, solidification experiments
of Si-Al alloys containing B by Ti addition were performed, and the effect of Ti addition on the solidification refining of
Si with the Si-Al melt was successfully confirmed. 相似文献
23.
The gamma-ray-induced crosslinking of polyacrylamide was carried out under various conditions. The molecular weight of the polymer before inrradiation was found to be the most important factor for crosslinking. When polymers have low molecular weights such as 80,000, the intensity of radiation, the external pressure applied, and the water content of the polymer powder became important for crosslinking. Although the polycrylamide hydrogel can be obtained directly by irradiating the monomer, it was obtained more conveniently by the irradiation of monomer—polymer mixtures. The hydrogels obtained by the radiation with a dose of over 50 kgray, absorb water by 1000–1500 wt %. 相似文献
24.
Hideaki Katayama Tsutomu Tawa Shinzaburo Ito Masahide Yamamoto Yoshio Wada 《Polymer Bulletin》1992,29(3-4):365-367
Summary The effect of side chain length on intramolecular triplet energy migration of naphthalene containing polymers was investigated by a delayed fluorescence (DF) spectroscopy for the solid solution of the polymers. The degree of triplet energy migration depends strongly on whether the chromophores are directly attached to the main chain or not. 相似文献
25.
An attempt was made to deposit carbon films by electrolysis of a water-ethylene glycol solution. Carbon plate and an n-type silicon substrate were dipped in the solution and a high d.c. potential was negatively applied on the silicon substrate. Some deposits were observed in the region between the boiling point curve and the line approximately 50 °C below and parallel to the boiling point, when electrolysis was carried out at 1 kV for 6 h. For higher potentials of 1.4–2.0 kV and longer electrolysis of 12 h, some samples showed a broad X-ray diffraction peak and Raman peaks, corresponding to graphitic carbon. 相似文献
26.
Satohiro Yoshida Tsunehiro Tanaka Tomoko Hanada Takeshi Hiraiwa Hiroyoshi Kanai Takuzo Funabiki 《Catalysis Letters》1992,12(1-3):277-285
XANES of vanadium and niobium oxide on silica or alumina have been analyzed quantitatively by a deconvolution technique. Based on the results for reference compounds, local structures of supported vanadium and niobium species were identified. The composition was estimated from difference spectra for the samples which consisted of two kinds of species. 相似文献
27.
A Wada Y Masuda M Fukayama T Hatakeyama Y Yanagawa H Watanabe T Inamatsu 《Canadian Metallurgical Quarterly》1996,40(10):767-771
Zinc is an important trace element for immune function. Here, we show that zinc addition in a serum- and lipopolysaccharide-free cell culture system leads to significantly enhanced levels of interleukin 1 beta (IL-1 beta) and tumour necrosis factor alpha (TNF-alpha) and to expression of the corresponding mRNA in human peripheral blood mononuclear cells (PBMC). Structurally related divalent cations like cobalt, nickel, and mercury also partially increase monokine secretion but to a much lower and thus insignificant extent. They fail to induce mRNA of TNF-alpha after 3 h of culture. Therefore, monokine induction is a zinc-specific effect influenced by the physicochemical properties of the ion. Confirmation of the unique significance of zinc for immune function provides a better understanding of the mechanisms of specific zinc-mediated immune modulation. 相似文献
28.
29.
Eiichi Haginomori Kenji Yoshimura Shunichi Kobayashi Sadanori Kaneko Takeshi Yokota Masayuki Ishikawa 《Electrical Engineering in Japan》1994,114(4):50-61
To cope with the high rate of increase of power demand in the main industrialized districts in Japan, 550-kV transmission systems covering the districts have been reinforced, with most of the main power plants connected directly to these systems. Through 550-/300-kV substations, the majority of power to the districts is supplied by 300-kV systems. To limit the excess short-circuit capacity in the 300-kV systems, they tend to be reconstructed as so-called radial networks. In radial networks with high short-circuit capacity and relatively small number of transmission lines connected to the substation busbars, the rate of rise of TRV can be far higher than standard value. This paper analyzes the transient recovery voltages (TRV) in such extra-high-voltage radial networks in Japan, together with the relevant stresses to circuit-breakers during fault clearings. Future system conditions have also been introduced. As the typical rate of rise of the TRV values, more than twice that of today's standard ones are probable. 相似文献
30.
This study was undertaken to compare the calcium-independent phospholipase A2 (PLA2) activities in the cytosols of twelve rat tissues and to determine whether their activities were distinct. 1-O-Alk-1′-enyl-2-[14C]-oleoyl-sn-glycero-3-phosphocho-line (PlsC) and 1-O-Alk-1′-enyl-2-[14C]oleoyl-sn-glycero-3-phosphethanolamine (PlsE) were synthesized and used as substrates, instead of phosphatidyl compounds, to exclude
hydrolysis by cytosolic PLA1 activity that could be present in some of the cytosolic preparations. For each tissue, we examined substrate specificity,
pH optimum, and effect of adenosine triphosphate (ATP) and ATP analogues. PLA2 activity was detected in eleven out of the twelve issues examined. Based on substrate specificity and pH optimum, cytosolic
calcium-independent PLA2 were classified in three groups. The first group, which included PLA2 from small intestine, stomach and spleen, had the highest specific activity with PlsC as substrate (1253, 309 and 75 nmol/mg
protein/hour, respectively) and an optimal pH at 6.5. Activity with PlsE as substrate was much lower (20–37%) than with PlsC.
The second group of PLA2 activities included the cytosolic activities from thymus, lung, liver and pancreas that showed lower specific activities
for both substrates (14–23 nmol/mg protein/hour with PlsC) and had a broader optimal pH range of 6.1 to 7.5. The cytosols
from brain, kidney, heart and muscle comprised the third PLA2 group that was found to have a higher specific activity with PlsE (5–20 nmol/mg protein/hour) than PlsC and an optimal pH
range from 7.4 to 7.9. Since the highest specific activity was found in the cytosol from small intestine, this PLA2 was examined further. PLA2 activity was found to be equally distributed in the cytosol of the submucosal portion of duodenum, jejunum and ileum with
an optimal pH of 6.1 and a 5-fold higher activity with PlsC than PlsE as substrate. Moreover, this PLA2 activity was inhibited by treatment with detergents. These results indicate the presence in the submucosal portion of the
intestine of a calcium-independent cytosolic PLA2 with a high specific activity toward PlsC and properties distinct from those described for the PLA2 found in the intestinal brush-border. 相似文献