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排序方式: 共有961条查询结果,搜索用时 31 毫秒
71.
Tomohiro Yamaguchi Teruyoshi Yoshimura Tomohiko Yamakami Seiichi Taruta Kunio Kitajima 《Microporous and mesoporous materials》2008,111(1-3):285-291
New porous solids from alumina-pillared fluorine micas (APMs), which were obtained from synthetic Na-tetrasilicic fluorine mica [NaMg2.5Si4O10F2], were prepared by sulfuric acid-treatment under mild conditions at 25 °C. The products were investigated by XRD, ICP, SEM, TEM and N2 adsorption–desorption isotherm at 77 K. XRD measurements indicated that the interlayer pillared structure having a large basal spacing collapsed during the early stages of the acid-treatment. ICP analyses indicated that Al3+ and Mg2+ ions were leached out from the pillared micas during the acid-treatment. The pore properties of the leached products were found to differ from those of the mother pillared micas: the acid leaching of the pillared micas leads to the formation of mesopores around 3.2 nm in diameter. The correlation between the change in pore properties and cation elution behavior suggests that the mesopore formation results from the leaching of Mg2+ ions from the octahedral sheet of the pillared micas. The leached products thus obtained retained the flaky morphology of the mother pillared micas. These results show that the mild acid-treatment using APMs provides a novel route for obtaining unique mesopore solids having the large particle sizes of the mother micas. 相似文献
72.
Izumi Kita Tomohiro Shibata Yuki Kamiya Daishi Kato Kazuo Kunieda Keiji Yamada Kazushi Ikeda 《Artificial Life and Robotics》2009,14(3):375-378
To increase the productivity of knowledge workers, it is necessary to manage their organization so that they are motivated
to collaborate with each other for their synergy. However, it is difficult for managers to grasp the explicit interactions
of workers in the organization all the time. Owing to advanced communications technology, and the reduced size and improved
capabilities of computers, we are able to record group behaviors as logging data in the office. The aim of this study is to
extract features of group behavior from long-range office-logging data. We apply principal component analysis to the data
matrix whose element is the mean travel velocity calculated from an individual’s trajectory per day. The results demonstrate
the feasibility of our approach, since nontrivial informative group features can be extracted. 相似文献
73.
Hiroaki Inoue Yuji Arai Tsunao Kishida Ryu Terauchi Kuniaki Honjo Shuji Nakagawa Shinji Tsuchida Tomohiro Matsuki Keiichirou Ueshima Hiroyoshi Fujiwara Osam Mazda Toshikazu Kubo 《International journal of molecular sciences》2015,16(1):1043-1050
Hypoxia-inducible factor (HIF)-2α is considered to play a major role in the progression of osteoarthritis. Recently, it was reported that pressure amplitude influences HIF-2α expression in murine endothelial cells. We examined whether hydrostatic pressure is involved in expression of HIF-2α in articular chondrocytes. Chondrocytes were cultured and stimulated by inflammation or hydrostatic pressure of 0, 5, 10, or 50 MPa. After stimulation, heat shock protein (HSP) 70, HIF-2α, nuclear factor kappa B (NF-κB), matrix metalloproteinase (MMP)-13, MMP-3, and vascular endothelial growth factor (VEGF) gene expression were evaluated. The levels of all gene expression were increased by inflammatory stress. When chondrocytes were exposed to a hydrostatic pressure of 5 MPa, HIF-2α, MMP-13, and MMP-3 gene expression increased significantly although those of HSP70 and NF-κB were not significantly different from the control group. In contrast, HIF-2α gene expression did not increase under a hydrostatic pressure of 50 MPa although HSP70 and NF-κB expression increased significantly compared to control. We considered that hydrostatic pressure of 5 MPa could regulate HIF-2α independent of NF-κB, because the level of HIF-2α gene expression increased significantly without upregulation of NF-κB expression at 5 MPa. Hydrostatic pressure may influence cartilage degeneration, inducing MMP-13 and MMP-3 expression through HIF-2α. 相似文献
74.
Ultrasonic welding of mild steel sheet (SPCC) and aluminium alloy sheet (A5052) was conducted using two different weld tips of a knurled tip (K-tip) and a curved shape tip without knurled edges (C-tip). Behaviours of the weld tip and the welded materials during the weld process were analysed using a high-speed camera observation and an image correlation. The C-tip welding shows a completely different displacement behaviour from the K-tip welding; a relative motion between the tool tip and A5052 in contact with the tip predominantly occurs in the C-tip in contrast to a relative motion between A5052 and SPCC observed in the K-tip. The joint strength using the C-tip was higher than that using the K-tip under the weld conditions in this study. It is demonstrated that the relative motion behaviour in the C-tip causes a macroscopic deformation of A5052 in the vibration direction. This phenomenon promotes growth of a bonded region, resulting in the increase of joint strength. It is surmised that Fe–Al intermetallic layer forms at the weld interface, and the joint strength consequently decreases for the longer weld time condition. 相似文献
75.
Sheng Zhang Hirotomo Nakano Yonglin Xiong Tomohiro Nishimura Feng Zhang 《岩石力学与岩土工程学报(英文版)》2010,2(3):255-261
In deep geological disposal of high-level nuclear waste,one of the most important subjects is to estimate long-term stability and strength of host rock under high temperature conditions caused by radioactive decay of the waste.In this paper,some experimental researches on the thermo-mechanical characteristics of soft sedimentary rock have been presented.For this reason,a new temperature-controlled triaxial compression and creep test device,operated automatically by a computer-controlled system,whose control software has been developed by the authors,was developed to conduct the thermo-mechanical tests in different thermal loading paths,including an isothermal path.The new device is proved to be able to conduct typical thermo-mechanical element tests for soft rock.The test device and the related testing method were introduced in detail.Finally,some test results have been simulated with a thermo-elasto-viscoplastic model that was also developed by the authors. 相似文献
76.
Development and characterization of micro-dispersed lacquer 总被引:1,自引:1,他引:0
本文利用一种特制的搅拌装置来制备微分散生漆。研究了在不同的搅拌速率和搅拌时间下所获得的生漆微粒子的直径和性能的关系。粒度分布测定表明,经过60分钟且每分钟240转搅拌处理的生漆,其粒子直径分布最窄,平均为0.194微米。凝胶色谱(GPC)分析显示生漆中的寡聚体增加的同时单体的百分含量减少了,意味着在搅拌的过程中发生了聚合反应。另外,微分散生漆的粘度、干燥成膜时间、膜亮度、膜颜色、膜光泽以及耐紫外线等特性也作了深入的探讨。 相似文献
77.
In this study, we used the minute gas–liquid interfaces around CO2/NH3 microbubbles as new reaction fields where the crystal nucleation progresses and developed a crystallization technique to control the polymorphism of calcium carbonate (CaCO3). In the regions around the gas–liquid interfaces of CO2/NH3 microbubbles, Ca2+ and CO32− ion concentrations can be adjusted because of the characteristic of the electric charge on the bubble surface and the decrease in CO2 concentration based on unit bubble caused by minimization of bubble size, and because of the pH difference between local pH at the gas–liquid interface and overall pH in the bulk liquid caused by mixing of NH3 with CO2; hence, the polymorph change of CaCO3 is expected to occur. CaCO3 was crystallized at 298 K by a semi-batch type reaction in which CO2/NH3/N2 bubbles were continuously supplied to an aqueous Ca(NO3)2 solution using a self-supporting bubble generator. The solution pH during crystallization was maintained at a constant level of 6.9–12.0 by adding HNO3 and NH4OH solution. The average bubble size (dbbl) was varied in the range of 40–1000 μm by controlling the N2 flow rate, and the molar ratio of CO2/NH3 (αCO2/NH3) was set at a specified value of 0.20–1.00 at a constant CO2 flow rate. The following results were obtained by varying solution pH, dbbl, and αCO2/NH3: at a constant dbbl of 40 μm and αCO2/NH3 of 0.20, vaterite and calcite were major products at a solution pH lower than 9.0 and at a solution pH greater than 11.0, respectively, while aragonite was crystallized predominantly in the solution pH range of 9.7–10.5; at a constant solution pH of 9.7 the crystallization of aragonite was accelerated remarkably with a decrease in αCO2/NH3 and dbbl. 相似文献
78.
Miwa N Nishio T Arita Y Kawamori F Masuda T Akiyama M 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2003,44(6):289-293
Vibrio parahaemolyticus densities in spiked and naturally contaminated seafood samples were enumerated by the MPN method combined with a PCR procedure (MPN-PCR method) targeting the species-specific thermolabile hemolysin gene (tlh), and by the MPN method using subcultivation of alkaline-peptone-water (APW) enrichment culture on thiosulfate-citrate-bile-sucrose (TCBS) agar (MPN-TCBS method). In the samples spiked with both V. parahaemolyticus and V. alginolyticus, the numbers of V. parahaemolyticus enumerated by the MPN-PCR method were similar to, or higher than the numbers of spiked cells, whereas those enumerated by the MPN-TCBS method were below the numbers of spiked cells. In naturally contaminated seafood samples, the numbers of V. parahaemolyticus enumerated by the MPN-PCR method were higher than those by the MPN-TCBS method. In the case of the MPN-TCBS method, isolation of V. parahaemolyticus from some APW cultures was difficult because of the overgrowth of many colonies other than V. parahaemolyticus (e.g., V. alginolyticus) on TCBS agar. In contrast, the PCR technique could detect tlh from APW culture without isolation of V. parahaemolyticus, so the possibility of failing to obtain a positive result in APW culture by the MPN-PCR method was considered to be lower than that by the MPN-TCBS method. Furthermore, utilization of the PCR technique reduces the time and labor required for the biochemical identification tests used in the MPN-TCBS method. For the detection and enumeration of V. parahaemolyticus in seafood, especially for samples that show many colonies other than V. parahaemolyticus on TCBS agar, the MPN-PCR method may be more convenient and reliable than the MPN-TCBS method. 相似文献
79.
Tomohiro Itoh Kenji Ohguchi Chizuru Nakajima Masayoshi Oyama Munekazu Iinuma Yoshinori Nozawa Yukihiro Akao Masafumi Ito 《Food chemistry》2011
We found that two distinct flavonoid glycosides isolated from the peel of Japanese persimmon (Diospyros kaki Fuyu), isoquercitrin (Isq) and hyperin (Hyp), are capable of inhibiting antigen-stimulated degranulation in rat basophilic leukaemia RBL-2H3 cells. In order to elucidate the underlying mechanisms, we examined effects of Isq and Hyp on cellular responses induced by antigen stimulation. Treatment with both Isq and Hyp markedly inhibited antigen-stimulated elevation of intracellular free Ca2+ concentration and reactive oxygen species (ROS). Isq and Hyp did not affect NADPH oxidase (NOX) activity, but they possessed DPPH radical-scavenging activity similar to that of epigallocatechin gallate, a potent anti-oxidant, Finally, Isq and Hyp showed little or no effects on Ag-stimulated Syk activation or phosphorylation of signalling molecules. These results indicate that inhibition of antigen-stimulated degranulation by Isq and Hyp is mainly due to suppression of intracellular Ca2+ elevation, which is caused by direct scavenging of ROS that are generated by NOX. Our findings suggest that Isq and Hyp, isolated from the peel of persimmon, would be beneficial for alleviating symptoms of type I allergy. 相似文献
80.
Yosuke Higo Fusao Oka Tomohiro Sato Yoshiki Matsushima Sayuri Kimoto 《Soils and Foundations》2013,53(2):181-198
In this paper, localized deformation in partially saturated sand was investigated quantitatively using microfocus X-ray computed tomography (CT) and an image analysis of the CT images. Triaxial compression tests on a partially saturated dense Toyoura sand specimen were carried out under a low confining pressure and under drained conditions for both air and water. The development of localized deformation was observed macroscopically using microfocus X-ray CT, and the displacement field over the entire specimen was quantified by an image analysis of the CT images with the digital image correlation (DIC) technique. The progressive development of shear bands is discussed with reference to these images. In addition, the region of localization was observed microscopically by partial CT scanning on a micron scale with high spatial resolution. Changes in the particulate structures are also discussed herein. The DIC image analysis of the partial CT images provided a microscopic displacement field and indicated that very fine localized shear deformation developed before the shear bands had become visible in the macroscopic investigation. 相似文献