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排序方式: 共有1422条查询结果,搜索用时 15 毫秒
41.
Heat and mass transfer with electrochemical reaction in an anode-supported flat-tube solid oxide fuel cell (FT-SOFC) is studied by means of three-dimensional numerical simulation. The distributions of the reaction fields in the anode-supported FT-SOFC are found to be similar to those in the planar SOFC with co-flow arrangement. However, in comparison with the latter, the concentration and activation overpotentials of the former can be reduced by additional reactant diffusion through the porous rib of the fuel channel. Parametric survey reveals that, for a fixed activation overpotential model, the output voltage can be improved by increasing the pore size of anode, while the cross-sectional geometry has smaller effect on the cell performance. Based on the results of three-dimensional simulation, we also develop a simplified numerical model of anode-supported FT-SOFC, which takes into account the concentration gradients in the thick anode of complex cross-sectional geometry. The simplified model can sufficiently predict the output voltage as well as the distributions of temperature and current density with very low computational cost. Thus, it can be used as a powerful tool for surveying wide range of anode-supported FT-SOFC design parameters. 相似文献
42.
Corrosion characteristics of reduced activation ferritic steel, JLF-1 (8.92Cr–2W) in molten salts Flibe and Flinak 总被引:1,自引:0,他引:1
Masatoshi Kondo Takuya Nagasaka Qi Xu Takeo Muroga Akio Sagara Nobuaki Noda Daisuke Ninomiya Masaru Nagura Akihiro Suzuki Takayuki Terai Naoki Fujii 《Fusion Engineering and Design》2009,84(7-11):1081-1085
Static corrosion tests were performed in molten salts, LiF–BeF2 (Flibe) and LiF–NaF–KF (Flinak), at 500 °C and 600 °C for 1000 h. The purpose is to investigate the corrosion characteristics of reduced activation ferritic steels, JLF-1 (8.92Cr–2W) in the fluids. The concentration of hydrogen fluoride (HF) in the fluids was measured by slurry pH titration method before and after the exposure. The HF concentration determined the fluoridation potential. The corrosion was mainly caused by dissolution of Fe and Cr into the fluids due to fluoridation and/or electrochemical corrosion. Carbon on the surface might be dissolved into the fluids due to the corrosion, and this resulted to the decrease of carbide on the surface. The corrosion depth of the JLF-1 specimen, which was obtained from the weight losses, was 0.637 μm in Flibe at 600 °C and 6.73 μm in Flinak at 600 °C. 相似文献
43.
Naoki Motomura Yuto Yamazaki Daiki Koga Shogo Harashima Xin Gao Yuta Tezuka Kei Omata Yoshikiyo Ono Ryo Morimoto Fumitoshi Satoh Yasuhiro Nakamura Go Eun Kwon Man Ho Choi Akihiro Ito Hironobu Sasano 《International journal of molecular sciences》2022,23(4)
Cortisol-producing adenoma (CPA) is composed of clear and compact cells. Clear cells are lipid abundant, and compact ones lipid poor but associated with higher production of steroid hormones. PRKACA mutation (PRKACA mt) in CPA patients was reported to be associated with more pronounced clinical manifestation of Cushing’s syndrome. In this study, we examined the association of histological features and genotypes with cholesterol uptake receptors and synthetic enzymes in 40 CPA cases, and with the quantitative results obtained by gas chromatography-mass spectrometry (GC-MS) analysis in 33 cases to explore their biological and clinical significance. Both cholesterol uptake receptors and synthetic enzymes were more abundant in compact cells. GC-MS analysis demonstrated that the percentage of compact cells was inversely correlated with the concentrations of cholesterol and cholesterol esters, and positively with the activity of cholesterol biosynthesis from cholesterol esters. In addition, hormone-sensitive lipase (HSL), which catalyzes cholesterol biosynthesis from cholesterol esters, tended to be more abundant in compact cells of PRKACA mt CPAs. These results demonstrated that both cholesterol uptake and biosynthesis were more pronounced in compact cells in CPA. In addition, more pronounced HSL expression in compact cells of PRKACA mt CPA could contribute to their more pronounced clinical manifestation. 相似文献
44.
Kyoungkeun Yoo Soo-kyung Kim Jae-chun Lee Mayumi Ito Masami Tsunekawa Naoki Hiroyoshi 《Minerals Engineering》2010,23(6):471-477
The effect of chloride on chalcopyrite leaching has been investigated by performing batch leaching tests with three kinds of leaching solutions and using Hiroyoshi’s model, which suggests that a zone of rapid leaching exists between the critical potential (Ec, equilibrium redox potential for the reduction of CuFeS2 to Cu2S) and the oxidation potential (Eox, equilibrium redox potential for the oxidation of Cu2S). The results of the leaching tests show that the leaching rate in hydrochloric acid solution is the fastest and that the relationship between the Cu leaching rate and oxidation–reduction potential (ORP) follows Hiroyoshi’s model. Thermodynamic calculations indicate that, with an increase in the chloride concentration, the concentration of cuprous ions increases as the chlorocuprate(I) complex ions are formed and the contribution of cuprous ions to the critical potential is greater than that of cupric ions, even though the concentration of cuprous ions is lower than that of cupric ions. This fact suggests that the formation of chlorocuprate(I) ions in a chloride solution may improve the chalcopyrite leaching rate by increasing the critical potential. 相似文献
45.
Masaru Ishii Mikihisa Saito Fumiyuki Fujii Michihiro Matsui Naoki Itamoto 《Electrical Engineering in Japan》2010,170(1):8-15
Lightning electric‐field waveforms related to power line faults in winter have been identified. Most of those waveforms appear to be associated with upward lightning discharges with absolute peak currents of over 100 kA. They are quite different from common return‐stroke waveforms, and the lightning discharges which produce these characteristic waveforms are called GC (Ground to Cloud) flashes. These high‐current lightning discharges are distributed around the coastline in different ways depending on their polarities. The spatial distributions of high‐current lightning discharges around Japan are also investigated. It is revealed that the region of Honshu Island along the coastline of the Sea of Japan belongs to the area in which the density of high‐current lightning flashes is the highest in Japan through the year. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(1): 8–15, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20874 相似文献
46.
47.
Naoki Izawa Tomoko Hanamizu Toshiro Sone Katsuyoshi Chiba 《Journal of Bioscience and Bioengineering》2010,109(4):356-360
To increase the hyaluronic acid (HA) yield from Streptococcus thermophilus YIT 2084, fermentation conditions (pH, temperature, agitation, aeration) were optimized in milk-based medium, and the effects of supplemental soybean peptides, which have different molecular weight distributions, were determined. HA production was enhanced to approximately 100 mg/l at pH 6.8 and 33–40 °C. Agitation speed and aeration rate slightly affected HA production. Soybean peptides including those of high molecular weight (approximately 27 to 130 kDa) further increased HA production to 208 mg/l under the optimal condition (pH 6.8, 35 °C, 100 rpm), which was 20-fold greater than non-optimal condition. HA production was no longer related to the specific growth rate. The HA produced under the optimal condition included a large amount of high-molecular-weight fraction of 100 to 2000 kDa, compared with under the basal condition without optimization. 相似文献
48.
Keiichiro Sugimoto Sayaka Sakamoto Kazuya Nakagawa Shuichi Hayashi Naoki Harada Ryoichi Yamaji Yoshihisa Nakano Hiroshi Inui 《Food chemistry》2011
Eucalyptus leaf extract (ELE) is rich in hydrolyzable tannins. We examined the effects of ELE and its constituents on lipopolysaccharide (LPS)-induced liver injury in mice. Mice fed a diet supplemented with 1% ELE were intraperitoneally administered LPS. Six hours later, the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were significantly lower in the ELE-supplemented mice than in the controls; LPS-induced hepatic inducible nitric oxide synthase (iNOS) expression was also suppressed. ELE lowered LPS-stimulated iNOS expression in cultured RAW 264.7 macrophages. Furthermore, the aglycones of hydrolyzable tannins, gallic acid (GA) and ellagic acid (EA), inhibited iNOS induction to a greater extent than did ELE (15-fold higher). When mice were fed a 1% GA or EA diet, the increase in the serum ALT and AST activities and hepatic iNOS expression in response to the LPS challenge were significantly attenuated. Thus, hydrolyzable tannins in ELE ameliorate LPS-induced liver injury. 相似文献
49.
Hiroyuki Kamata Shun-ichiro Ueno Naoki Sato Toshiyuki Naito 《Fuel Processing Technology》2009,90(7-8):947-951
Mercury oxidation by hydrochloric acid over the metal oxides supported by anatase type TiO2 catalysts, 1 wt.% MOx/TiO2 where M = V, Cr, Mn, Fe, Ni, Cu, and Mo, was investigated by the Hg0 oxidation and the NO reduction measurements both in the presence and absence of NH3. The catalysts were characterized by BET surface area measurement and Raman spectroscopy. The metal oxides added to the catalyst were observed to disperse well on the TiO2 surface. For all catalysts studied, the Hg0 oxidation by hydrochloric acid was confirmed to proceed. The activity of the catalysts was found to follow the trend MoO3 ~ V2O5 > Cr2O3 > Mn2O3 > Fe2O3 > CuO > NiO. The Hg0 oxidation activity of all catalysts was depressed considerably by adding NH3 to the reactant stream. This suggests that the metal oxide catalysts undergo the inhibition effect by NH3. The activity trend of the Hg0 oxidation in the presence of NH3 was different from that observed in its absence. A good correlation was found between the NO reduction and the Hg0 oxidation activities in the NH3 present condition. The catalyst having high NO reduction activity such as V2O5/TiO2 showed high Hg0 oxidation activity. The result obtained in this study suggests that the oxidation of Hg0 proceeds through the reaction mechanism, in which HCl competes for the active catalyst sites against NH3. NH3 adsorption may predominate over the adsorption of HCl in the presence of NH3. 相似文献
50.
Masahiro Kotani Yusuke Yasufuku Naoki Inoue Ken Kurihara Hiroyuki Kawada 《Mechanics of Time-Dependent Materials》2013,17(2):261-274
This study aims to investigate the effects of a hydrothermal environment on the creep behavior of woven glass fiber reinforced plastics (GFRPs) and to propose a method for predicting their lifetime. Toward this end, experiments were carried out in air and deionized water at 40, 60, 80 and 95 °C. Static tensile tests of woven GFRP were conducted in air and in deionized water to evaluate its mechanical properties and to determine suitable experimental conditions for subsequent constant tensile load tests. The mechanical properties of the woven GFRP decreased with an increase in temperature and with water immersion. Constant tensile load tests were also conducted in air and in deionized water to investigate the creep behavior and fracture time. The fracture time decreased with an increase in stress and water temperature and demonstrated the possibility of a threshold stress for fracturing. In addition, the fracture time during each constant tensile load test was predicted using a modified Reiner–Weissenberg (R-W) criterion, which is a failure criterion for linear viscoelastic materials based on the accumulation of dissolved energy within the GFRP. In this study, the R-W criterion was modified to consider the effects of degradation and its acceleration, which are due to the applied stress and immersion in a solution. The predicted results were in good agreement with the experimental data when considering the effects of hydrothermal aging. 相似文献