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51.
A. Satsuma K. Yamada K. Sato K. Shimizu T. Hattori Y. Murakami 《Catalysis Letters》1997,45(3-4):267-269
Partially protonated alkaline mordenites showed higher activity per acid amount below 573 K than acidic zeolites for the selective
reduction of NO with C3H6 in the presence of O2, which can be related to a high concentration of NO3
- species in the zeolite channels.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
52.
Isotactic polypropylene and ethylene-1-hexene copolymers containing 32 and 57 mol% of 1-hexene copolymers blends (i-PP/EH32 and i-PP/EH57) were prepared by solution blending, precipitating followed by drying and hot pressing. The two blends were subject to investigation on structure and mechanical properties of these blends under uniaxial drawing. The i-PP/EH32 and i-PP/EH57 represented the immiscible and miscible blends, respectively. The tensile stresses and strains at breaking point of i-PP/EH57 were remarkably higher than those of i-PP/EH32 at room temperature. From wide-angle X-ray diffraction (WAXD) measurement, it was observed that the orientation of crystallites occurred early and then propagated gradually up to about drawing ratio 8 because chains of EH57 copolymer were incorporated into the amorphous regions between lamellae of i-PP. In the WAXD patterns of i-PP/EH57, the oriented spot reflections coexsisted with unoriented ring reflections up to draw ratio higher than in pure i-PP. On the other hand, the two-phase structure was observed from TEM and AFM in i-PP/EH32, and on the drawing, separation at the interface between two-phase was observed in i-PP/EH32 even at the low strain. 相似文献
53.
Glow discharge polymerizations of tetramethoxysilane (TMOS), tetramethylsilane/oxygen mixture (½ molar ratio) (TMS/O2), hexamethyldisiloxane (HMDSO), and tetramethyldisiloxane (TMDSO) were carried out for the preparation of thin, polymeric films with siloxane structures. The chemical composition of the formed polymers was examined by elemental analysis, infrared spectroscopy, and electron spectroscopy for chemical analysis (ESCA) in connection with polymerization conditions, especially, a level of the radiofrequency (rf) input power per mass of the monomers (W/FM value). The polymers prepared from HMDSO at fairly low W/FM values resembled in chemical composition the conventionally polymerized polydimethylsiloxane. The surface properties of the formed polymers also were evaluated by the measurement of surface energy. 相似文献
54.
Yasushi Murakami Taki Matsumoto Kiyochika Yahikozawa Yoshio Takasu 《Catalysis Today》1995,23(4):383-389
The sol-gel process for the hydrolysis and polycondensation of tin tetra-n-butoxide in butanol was followed by viscosity measurements. The precipitation of tin-containing ultrafine particles was observed without any variation in the solution viscosity in the absence of diethylene glycols, while the viscosity increase was made without any precipitation by the addition of diethylene glycol. The induction period and the rate of the viscosity increase after the induction period was independent of the diethylene glycol content but depended upon the water content. The Monte Carlo simulation data were consistent with data for the viscosity experiment. The simulation was based on a kinetic model of the slow hydrolysis of tin tetra-n-butoxide, the reverse reaction of hydrolysis, and the polycondensation of the hydroxy derivatives. 相似文献
55.
T. Sato T. Murakami T. Endo M. Shimada K. Komeya T. Kameda M. Komatsu 《Journal of Materials Science》1991,26(7):1749-1754
Corrosion behaviour of Si3N4 ceramics containing Y2O3, Al2O3 and AIN as sintering aids was investigated under hydrothermal conditions at 200–300 C and saturated vapour pressures of water for 1–10 days. Hydrothermal corrosion resulted in the dissolution of the Si3N4 matrix and the formation of a product layer consisting of the original grain-boundary phases and hydrated silica. The dissolution rate of Si3N4 ceramics decreased with decreasing crystallinity of the grain-boundary phase. The dissolution rate could be adequately described by a parabolic plot in the initial stage of the reaction. The apparent activation energies were 83.5–108 kJ mol–1, and the bending strength of the corroded samples decreased from 600 to 400 MPa in the initial stage of the reaction upto a weight loss of 0.004 g cm–2, and then was almost constant up to a weight loss of 0.012 g cm–2. 相似文献
56.
Hiroki Matsuo Tatsuya Murakami Junichiro Otomo 《Journal of the American Ceramic Society》2021,104(11):5740-5749
In proton-conducting oxides, analyses for their electronic structure contribute to the understanding of interactions between defects in them. In this study, electronic band alignment of (1−x)BaZr0.8Y0.2O3−δ(BZY)–xSrZr0.95Y0.05O3−δ(SZY) proton-conducting solid-solution system (BSZY) which has high defect concentration and the deep valence band is experimentally investigated. By using thin-film specimens for optical absorption measurements, absorption edges derived from electron transition from the valence band to the conduction band which was insensitive to the proton incorporation were clearly observed in spite of the high defect concentration. The obtained optical band gap energy increased from 5.61 to 5.89 eV with increasing x, which was consistent with a composition dependence of Zr(Y)O6 octahedral tilting. Ultraviolet photon-yield spectroscopy (UV-PYS) measurements under vacuum condition revealed that BZY and SZY had ionization energy of 6.98 and 7.31 eV, respectively, and thus the absolute energy levels of the valence band maximum and the conduction band minimum of BSZY were experimentally clarified. We propose that the combination of the optical absorption measurements using thin-film specimens and the UV-PYS measurements under vacuum condition is effective in evaluating fundamental electronic structures of proton-conducting oxides. 相似文献
57.
ABSTRACT Preparation of poly(thiophene-alt-pyrrole bearing mesogen) was carried out with Migita–Kosugi–Stille coupling type polycondensation with an aid of Pd(0) complex catalyst. The resultant polymer shows lyotropic liquid crystallinity with good film-forming property. The smectic fan-shaped texture is maintained after completion of evaporation of solvent from the polymer solution. The cast film having liquid crystal (LC) order shows light emission function upon irradiation of excitation light at 460 nm. The polymer shows LC domain emission. Mechanical orientation allows to yield LC domain aligned film with band structure. Chiral mesogenic side chain induces π-conjugated main chain helicity from distance in molecular level. 相似文献
58.
HiroyukiHoshino HiromitsuMurakami HideoYokota SatoshiSuda HidekiTsuge KoichiTerasaka ToshiakiWakabayashi 《材料热处理学报》2004,25(5):475-479
In quenching, the cooling uniformity is most important to diminish distortion occurring on work pieces. As a trial to accomplish uniform cooling, therefore, there exist various mixing methods of a quenchant and the quenchant circulation with an external pump has so far been the well accepted mixing method. However, this study proposes an advanced oscillation mixing method that can improve more the cooling uniformity in quenching. The proposed method includes a stirrer in oscillating motion, so that the simultaneous oscillating and mixing movements of the stirrer are considered to provide efecfively the uniform cooling characteristics for the quenchant. In comparison with the case of the circulation pump mixing, the investigation using the oscillation mixing method has demonstrated the following two experimental facts:(1) the short vapor blanket stage caused by the quick breakage of the oil vapor blanket and (2) the reduced variation of the quenching distortion. 相似文献
59.
60.
A. Ohmori Z. Zhou K. Inoue K. Murakami T. Sasaki 《Journal of Thermal Spray Technology》1996,5(2):134-138
The penetration phenomena of liquid manganese (Mn) alloy into porous ZrO2 (8 vvt % Y2O3) coating plasma sprayed on SS400 steel substrate was studied by heating in a vacuum atmosphere. The improvement in mechanical
properties of the coating by heat treatment with liquid Mn alloys was examined. Liquid Mn alloys, such as Mn-Cu, Mn-Sn, and
Mn-In, rapidly penetrated the coating and formed a chemical bond between the coating and the substrate. The densification
of the ZrO2 coating occurred when ZrO2 particles were sintered with liquid Mn alloys that penetrated the porous coating. The dense coating was free of porosity,
and its hardness increased after heat treatment with Mn alloys, compared with assprayed ZrO2 coating. Moreover, the fracture toughness of the coating reached the same levels as those of sintered yttria-stabilized PSZ. 相似文献