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21.
Wataru Sugimoto 《Electrochimica acta》2004,49(2):313-320
The pseudocapacitance of nanocrystalline RuO2 with BET surface area of 42 m2 g−1 was evaluated using a RuO2 modified Glassy Carbon (RuO2/GC) thin film electrode. The charge storage behavior of the RuO2/GC thin film electrode was studied from fast to slow scan cyclic voltammetry between various potential windows. The utilization of the thin film electrode method for nanocrystalline RuO2 with known specific surface area allowed a semi-quantitative understanding of the electric double-layer capacitance (Cdl), adsorption related charge (Cad), and the irreversible redox related charge (Cirr) per unit mass and surface area of RuO2. Comparison of the cyclic voltammograms between different voltage windows revealed that the contribution from Cirr is especially dominant below 0.4 V (versus RHE) at slow scan rates. 相似文献
22.
Ionic conductivity of polymer gels deriving from alkali metal ionic liquids and negatively charged polyelectrolytes 总被引:1,自引:0,他引:1
We have prepared polymer gel electrolytes with alkali metal ionic liquids (AMILs) that inherently contain alkali metal ions. The AMIL consisted of sulfate anion, imidazolium cation, and alkali metal cation. AMILs were mixed directly with poly(3-sulfopropyl acrylate) lithium salt or poly(2-acrylamido-2-methylpropanesulfonic acid) lithium salt to form polymer gels. The ionic conductivity of these gels decreased with increasing polymer fraction, as in general ionic liquid/polymer mixed systems. At low polymer concentrations, these gels displayed excellent ionic conductivity of 10−4 to 10−3 S cm−1 at room temperature. Gelation was found to cause little change in the diffusion coefficient of the ionic liquid, as measured by pulse-field-gradient NMR. These data strongly suggest that the lithium cation migrates in successive pathways provided by the ionic liquids. 相似文献
23.
Wataru Kanematsu Tatsuya Miyajima Mutsuo Sando 《Journal of the American Ceramic Society》2001,84(10):2427-2429
A visualizing technique for indentation damage of ceramics was developed. Plasma etching was used to enhance the view of cracks and the subsurface microcracking crush zone following Knoop indentation of hot pressed Si3 N4 . The microcracking zone was readily identified from the surface view of the indented surface as a grain-falling-off region (GFOR), defined as a region in which grains were removed by preferential etching using CF4 gas, followed by ultrasonic cleaning. A fissure-like opening corresponding to the indentation cracks was also observed. It is inferred that the formation of the GFOR region and the fissure-like opening were caused by the etching/cleaning treatment. Meanwhile, the etching on a section which included diagonals of the impression provided a section view of the microcracking zone. 相似文献
24.
Phase Relations and Volume Changes of Hafnia under High Pressure and High Temperature 总被引:1,自引:0,他引:1
Osamu Ohtaka Hiroshi Fukui Taichi Kunisada Tomoyuki Fujisawa Kenichi Funakoshi Wataru Utsumi Tetsuo Irifune Koji Kuroda Takumi Kikegawa 《Journal of the American Ceramic Society》2001,84(6):1369-1373
Using multi-anvil high-pressure devices and synchrotron radiation, X-ray in situ observations of HfO2 under high pressure and high temperature have been performed to investigate its phase relations and compression behavior. An orthorhombic phase (orthoI) is stable from 4 to 14.5 GPa below 1250°–1400°C and transforms to a tetragonal phase, which is one of the high-temperature forms of HfO2 , above these temperatures. Another orthorhombic phase (orthoII) with a cotunnite-type structure appears above 14.5 GPa. OrthoII is stable up to 1800°C at 21 GPa. OrthoII is quenchable to ambient conditions. The orthoI-to-orthoII transition is accompanied by ∼8 vol% decrease. The bulk moduli of orthoI and orthoII at room temperature are 220 and 312 GPa, respectively. This low compressibility of orthoII indicates that it is a potential candidate for very hard materials. 相似文献
25.
Kouji Banno Yuya Nogami Iori Kisu Megumi Yanokura Kiyoko Umene Kenta Masuda Yusuke Kobayashi Wataru Yamagami Nobuyuki Susumu Daisuke Aoki 《International journal of molecular sciences》2013,14(6):12123-12137
The recent increase in the frequency of endometrial cancer has emphasized the need for accurate diagnosis and improved treatment. The current diagnosis is still based on conventional pathological indicators, such as clinical stage, tumor differentiation, invasion depth and vascular invasion. However, the genetic mechanisms underlying endometrial cancer have gradually been determined, due to developments in molecular biology, leading to the possibility of new methods of diagnosis and treatment planning. New candidate biomarkers for endometrial cancer include those for molecular epigenetic mutations, such as microRNAs. These biomarkers may permit earlier detection of endometrial cancer and prediction of outcomes and are likely to contribute to future personalized therapy for endometrial cancer. 相似文献
26.
Kenta Arai Wataru Shibagaki Reina Shinozaki Michio Iwaoka 《International journal of molecular sciences》2013,14(7):13194-13212
It has been well established that in the oxidative folding of hen egg white lysozyme (HEL), which has four SS linkages in the native state (N), three des intermediates, i.e., des[76–94], des[64–80], and des [6–127], are populated at 20 °C and N is dominantly formed by the oxidation of des[64–80] and des[6–127]. To elucidate the temperature effects, the oxidative folding pathways of HEL were reinvestigated at 5–45 °C in the presence of 2 M urea at pH 8.0 by using a selenoxide reagent, DHSox. When reduced HEL was reacted with 1–4 equivalents of DHSox, 1S, 2S, 3S, and 4S intermediate ensembles with 1–4 SS linkages, respectively, were produced within 1 min. After the oxidation, 3S was slowly converted to the des intermediates with formation of the native structures through SS rearrangement. At 5 °C, des[76–94] was populated in the largest amount, but the oxidation to N was slower than that of des[64–80] and des[6–127]. At 35 °C, on the other hand, des[64–80] and des[6–127] were no longer stable, and only des[76–94] was populated. The results suggested that the major folding pathways of HEL can be switched from one to the other by temperature control. 相似文献
27.
Wataru Muramatsu Hirofumi Yoshimatsu 《Advanced Synthesis \u0026amp; Catalysis》2013,355(13):2518-2524
The catalytic regio‐ and stereoselective monoglycosylation of carbohydrates using organotin catalysts is demonstrated. The one‐step reaction affords various oligosaccharides linked at the secondary hydroxy group in high chemical yield and good regio‐ and stereoselectivities. The regioselectivity of the glycosylation is shown to depend on the spatial arrangement of the hydroxy groups in the carbohydrates.
28.
Reduction of flash generated in a gas vent is of great concern for manufacturers of electronic parts. The present study proposes a theoretical model for flash generation through consideration of flow characteristics in a gas vent. The model predicts the factors controlling flash, i.e., material parameters such as zero‐shear viscosity, crystallization temperature, thermal conductivity, and heat capacity, and process parameters such as injection and mold wall temperatures, packing pressure, and the clearance of a gas vent. On the other hand, we measure the amount of flash generated in the molding of poly(phenylene sulfide) (PPS) composites containing glass fiber and spherical fillers (CaCO3 or Al2O3). Flash reduces with decreasing size of spherical fillers. These experimental data are successfully interpreted using the flash model. Polym. Eng. Sci., 45:198–206, 2005. © 2005 Society of Plastics Engineers 相似文献
29.
Proton conductive inorganic–organic hybrid membranes were synthesized from styrene derivatives of alkoxysilane and ethyl 2-[3-(dihydroxyphosphonyl)-2-oxopropyl] acrylate (EPA) through copolymerization followed by sol–gel reaction. Self-standing, homogeneous and transparent hybrid membranes with chemically bound phosphonic acid groups were synthesized. FT-IR analysis exhibited the hybrid membranes included phosphonic acid groups. 13C and 29Si NMR studies indicated that alkoxysilyl functionalized styrene derivatives were not only copolymerized with EPA but also condensed yielding Si–O–Si linkages by sol–gel reaction. TG–DTA analysis revealed that these membranes were thermally stable up to 200 °C in dry O2. The proton conductivities of the hybrid membranes increased with phosphonic acid content and temperature. The P/Si ratio of the membrane was dependent on the number of alkoxy group in the starting alkoxysilane. The hybrid membrane from (dimethylmethoxysilylmethyl)styrene (DMMSMS(M))/EPA = 1/6 revealed proton conductivities of 6.3 × 10−3 and 2.4 × 10−4 S cm−1 at 68.0% relative humidity and 18.8% relative humidity, respectively, at 140 °C. 相似文献
30.
Kyuya Nakagawa Wataru Murakami Julien Andrieu Sverine Vessot 《Chemical Engineering Research and Design》2009,87(8):1017-1027
Freeze-dried samples were prepared from D-mannitol solution by selected freezing conditions. Crystalline structures of prepared samples were determined by XRD analysis, and distributions of the various crystal structures of mannitol were obtained for each sample. It was found that the amount of each polymorph was quite well correlated to the freezing conditions, namely the ice crystal nucleation temperature and the cooling rate. In case of samples prepared at fast cooling rates, the samples where the ice crystals nucleated at higher temperature contained much more stable form than the samples nucleated at lower temperature. Besides, the samples prepared at slow cooling rates predominantly contained stable crystalline forms despite of the variation of nucleation temperatures. Moreover, the experimental results also indicated that the various polymorphs were also distributed vertically through the sample along the direction of the heat flux during freezing. The tendency of the polymorph distribution through the freeze-dried cake was also elucidated by using the simulated temperature profiles during freezing. Thus, the profiles of mannitol polymorphs after the freezing derived from the temperature distributions could predict the global tendency of polymorphism behaviour, and, consequently, would be useful to achieve quality control of freeze-dried formulations. 相似文献