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101.
Jae-Yeol Jeon Ryo Matsumoto Hiroshi Utsunomiya 《Journal of Materials Processing Technology》2014,214(11):2514-2521
Die quenching of AA2024 aluminum alloy billets was carried out on a servo press with ram-motion control of WC-20 mass%Co dies directly after solution heat treatment (SHT). To clarify the dependence on billet size for die quenching, two billets with a height of h0 = 8 mm or 16 mm and with the same diameter of 16 mm were prepared. The cylindrical billets were heated in an electric furnace at 823 K and transferred to the press. Then the billets were uniaxially compressed with a reduction in height (Δh/h0) of 2% or 5%, and further held between the dies. The sandwiching duration by dies (td.q.) was varied from 0 to 8 s. Based a measured temperature change, hardness and TG–DTA analysis, it is found that die quenching is successfully carried out without precipitation hardening only in the case of the billet with a height of 8 mm and td.q. > 6 s. The reduction in height is limited less than 5% by intergranular fracture on side surface of billet during the die quenching process. 相似文献
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105.
Motoyasu Tanaka Kazuyuki Kon Mizuki Nakajima Nobutaka Matsumoto Shinnosuke Fukumura Kosuke Fukui 《Advanced Robotics》2020,34(2):70-88
AbstractIn this work, we develop an articulated mobile robot that can move in narrow spaces, climb stairs, gather information, and operate valves for plant disaster prevention. The robot can adopt a tall position using a folding arm and gather information using sensors mounted on the arm. In addition, this paper presents a stair climbing method using a single backward wave. This method enables the robot to climb stairs that have a short tread. The developed robot system is tested in a field test at the World Robot Summit 2018, and the lessons learned in the field test are discussed. 相似文献
106.
Kengo Matsumoto 《Dynamical Systems: An International Journal》2017,32(3):423-459
λ-Graph systems are labelled Bratteli diagrams with shift operations. They present subshifts. Their matrix presentations are called symbolic matrix systems. We define skew products of λ-graph systems and study extensions of subshifts by finite groups. We prove that two canonical symbolic matrix systems are G-strong shift equivalent if and only if their presented subshifts are G-conjugate. 相似文献
107.
Takahiro Matsumoto Tetsuro Nose Yasuaki Nagata Katsuhiro Kawashima Tastuya Yamada Hidetoshi Nakano Satoshi Nagai 《Journal of the American Ceramic Society》2001,84(7):1521-1525
Young's modulus and Poisson's ratio of SiC ceramics at temperatures >1400°C were obtained using a laser ultrasonics method that included a Fabry-Pérot interferometer (LUFP). At temperatures <1000°C, Young's modulus and Poisson's ratio measured using the LUFP method agreed well with those measured using standard contact methods, such as the resonance method and the ultrasonic pulse method. These results showed that the LUFP method is a powerful tool for measuring high-temperature elastic properties of advanced ceramics in a noncontact manner. 相似文献
108.
Hirobumi Shibata Tomoaki Morita Taku Ogura Keishi Nishio Hideki Sakai Masahiko Abe Mutsuyoshi Matsumoto 《Journal of Materials Science》2009,44(10):2541-2547
Mesostructured zirconia particles having monoclinic-type crystalline walls were prepared using a low-temperature crystallization
technique. Crystalline zirconia particles with highly-ordered mesostructures were obtained through the sol–gel process of
zirconium sulfate tetrahydrate at 333 K in the presence of molecular self-assemblies of cetyltrimethylammonium bromide (CTAB)
or mixtures of CTAB and anionic molecules such as sodium dodecyl sulfate and sodium p-toluenesulfonate. Variations in the molar ratios of CTAB and the chemical species of anionic molecules led to the variations
in the periods of highly-ordered zirconia having crystalline walls. Calcination of the mesostructured zirconia particles prepared
using templates consisting solely of CTAB yielded crystalline mesoporous zirconia particles. 相似文献
109.
Cationic polymerization behavior of β‐methylglycidyl ether derivatives and physical properties of their cationically cured materials
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β‐Methylglycidyl ethers have been applied to Electrical and Electronic adhesives. However, there is no report about the detailed polymerization behavior and physical properties of their cured products. Hence, we investigated cationic polymerization behavior of bisphenol A di(β‐methylglycidyl) ether (Me‐BADGE) and physical properties of the cured products containing Me‐BADGE. DSC analysis suggested that Me‐BADGE could be cured completely at lower temperature than bisphenol A diglycidyl ether (BADGE). Physical properties were analyzed by dynamic viscoelastic analysis. Glass transition temperature (Tg) of BADGE homopolymer was 194°C. In contrast, the copolymer of BADGE (50 wt %) with Me‐BADGE (50 wt %) showed Tg at 124°C. According to the data of E’ and tan δ, crosslink density of the cured products decreased with increasing the Me‐BADGE content. The analysis of cationic polymerization of monofunctional β‐methylglycidyl ether suggested that the cationic polymerization proceeded not only through oxonium cation but also through carbocation formed by ring‐opening reaction of oxonium cation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42377. 相似文献
110.
Ryuta Shigefuku Hideaki Takahashi Hiroyasu Nakano Tsunamasa Watanabe Kotaro Matsunaga Nobuyuki Matsumoto Masaki Kato Ryo Morita Yousuke Michikawa Tomohiro Tamura Tetsuya Hiraishi Nobuhiro Hattori Yohei Noguchi Kazunari Nakahara Hiroki Ikeda Toshiya Ishii Chiaki Okuse Shigeru Sase Fumio Itoh Michihiro Suzuki 《International journal of molecular sciences》2016,17(9)
The progression of chronic liver disease differs by etiology. The aim of this study was to elucidate the difference in disease progression between chronic hepatitis C (CHC) and nonalcoholic fatty liver disease (NAFLD) by means of fibrosis markers, liver function, and hepatic tissue blood flow (TBF). Xenon computed tomography (Xe-CT) was performed in 139 patients with NAFLD and 152 patients with CHC (including liver cirrhosis (LC)). The cutoff values for fibrosis markers were compared between NAFLD and CHC, and correlations between hepatic TBF and liver function tests were examined at each fibrosis stage. The cutoff values for detection of the advanced fibrosis stage were lower in NAFLD than in CHC. Although portal venous TBF (PVTBF) correlated with liver function tests, PVTBF in initial LC caused by nonalcoholic steatohepatitis (NASH-LC) was significantly lower than that in hepatitis C virus (C-LC) (p = 0.014). Conversely, the liver function tests in NASH-LC were higher than those in C-LC (p < 0.05). It is important to recognize the difference between NAFLD and CHC. We concluded that changes in hepatic blood flow occurred during the earliest stage of hepatic fibrosis in patients with NAFLD; therefore, patients with NAFLD need to be followed carefully. 相似文献