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71.
H. Matsushima T. Nishida Y. Konishi Y. Fukunaka Y. Ito K. Kuribayashi 《Electrochimica acta》2003,48(28):2446-4125
Water electrolysis was conducted in both alkaline (25 wt.% KOH, 2 wt.% KOH) and acid (0.1N H2SO4) solutions for 8 s under microgravity environment realized in a drop shaft. The gas bubble formation of hydrogen and oxygen on platinum electrodes was observed by CCD camera. In alkaline solutions, a bubble froth layer grew on the electrode surface. Hydrogen bubble size was smaller than that of oxygen. The current density at constant potential decreased continually with time. In spite of the growth of a bubble froth layer on the electrode, the electrolysis never stopped, apparently because fresh electrolyte is supplied to the electrode surface by microconvection induced by the gas bubble evolution. In acid solution, hydrogen gas bubbles frequently coalesced on the cathode surface, yielding a larger average bubble than that of oxygen. The current density did not vary at constant potentials from –0.4 to −0.8 V versus reversible hydrogen electrode (RHE), because the effective electrode surface area was significantly reduced by the larger bubble size compared to alkaline electrolyte. The present experiments indicate that, especially in a microgravity environment, the bubble evolution behavior and the resultant current–potential curves are significantly influenced by the wettability of the electrode in contact with the electrolyte. 相似文献
72.
Sudip Adhikari Sunil Adhikary Ashraf M.M. Omer Mohamad Rusop Hideo Uchida Tetsuo Soga Masayoshi Umeno 《Diamond and Related Materials》2005,14(11-12):1824
Nitrogenated diamond-like (DLC:N) carbon thin films have been deposited by microwave surface wave plasma chemical vapor deposition on silicon and quartz substrates, using argon gas, camphor dissolved in ethyl alcohol composition and nitrogen as plasma source. The deposited DLC:N films were characterized for their chemical, optical, structural and electrical properties through X-ray photoelectron spectroscopy, UV/VIS/NIR spectroscopy, Raman spectroscopy, atomic force microscope and current–voltage characteristics. Optical band gap decreased (2.7 to 2.4 eV) with increasing Ar gas flow rate. The photovoltaic measurements of DLC:N / p-Si structure show that the open-circuit voltage (Voc) of 168.8 mV and a short-circuit current density (Jsc) of 8.4 μA/cm2 under light illumination (AM 1.5 100 mW/cm2). The energy conversion efficiency and fill factor were found to be 3.4 × 10− 4% and 0.238 respectively. 相似文献
73.
Shigenobu Kobayashi Tomiji Wakida Shouhua Niu Satoshi Hazama Taisuke Ito Yoshiyuki Sasaki 《Coloration Technology》1995,111(3):72-76
Three kinds of aramid fabrics, Technora (modified p-aramid), Conex (m-aramid) and Kevlar (p-aramid), were subjected to sputter etching and argon low-temperature plasma treatments after dyeing in black with disperse dyes. The depth of shade increased considerably on Technora and Kevlar with the sputter etching treatment, but not on Conex fabrics. Argon low-temperature plasma treatment had virtually no effect on the depth of shade on the aramid fabrics. 相似文献
74.
Takashi Yamashiki Toshihiko Matsui Keisuke Kowsaka Masayoshi Saitoh Kunihiko Okajima Kenji Kamide 《应用聚合物科学杂志》1992,44(4):691-698
A novel cellulose solution, prepared by dissolving an alkali-soluble cellulose, which was obtained by the steam explosion treatment on almost pure natural cellulose (soft wood pulp), into the aqueous sodium hydroxide solution with specific concentration (9.1 wt %) was employed for the first time to prepare a new class of multifilament-type cellulose fiber. For this purpose a wet spinning system with acid coagulation bath was applied. The mechanical properties and structural characteristics of the resulting cellulose fibers were compared with those of regenerated cellulose fibers such as viscose rayon and cuprammonium rayon commercially available. X-ray analysis shows that the new cellulose fiber is crystallographically cellulose II, and its crystallinity is higher but its crystalline orientation is slightly lower than those of other commercial regenerated fibers. The degree of breakdown of intramolecular hydrogen bond at C3[Xam(C3)] of the cellulose fiber, as determined by solid-state cross-polarization magic-angle sample spinning (CP/MAS) 13C NMR, is much lower than other, and the NMR spectra of its dry and wet state were significantly different from each other, indicating that cellulose molecules in the new cellulose fiber are quite mobile when wet. This phenomenon has not been reported for so-called regenerated cellulose fibers. 相似文献
75.
Masayoshi Ohashi Shoji Kawakami Yoshiyuki Yokogawa Gao-Chao Lai 《Journal of the American Ceramic Society》2005,88(9):2615-2618
It is necessary for encapsulants to have not only a suitable coefficient of thermal expansion (CTE) compatible to IC devices and a low dielectric constant to reduce the device propagation delay, but also a high thermal conductivity to dissipate large amounts of heat from power-hungry, high-speed IC and high-density packages. Fillers such as silica have been mixed with polymers to improve their properties. Aluminum nitride (AlN) is considered as an alternative one, because it has a higher theoretical thermal conductivity of ∼320 W/mK1 , a compatible CTE with silicon chips and a low dielectric constant. Commercial AlN fillers are angular in shape, because they are prepared via grinding coarse AlN powders synthesized by direct nitridation of aluminum metal and classification. The angular AlN are not expected to have high fluidity when mixed with polymers and hence low packing density. Recently, we successfully obtained single-crystalline spherical AlN fillers. Furthermore, polymer composites filled with the spherical AlN showed excellent thermal conductivity (>8 W/mK) as encapsulants for dissipating the heat generated in electronic devices. 相似文献
76.
Electrocodeposition of Sm and Co on a Cu substrate was investigated in a molten LiCl-KCl-SmCl3 (0.5 mol.%)-CoCl2 (0.1 mol.%) system at 723 K. Phase of the deposited Sm-Co alloys could be controlled by electrolysis potential. SmCo3 was formed on a Cu substrate by potentiostatic electrolysis in the potential range of 0.20-0.90 V (vs. Li+/Li). Sm2Co17 was obtained in the potential range of 0.90-1.50 V. 相似文献
77.
Koichiro Fukuda Iwao Maki Suketoshi Ito 《Journal of the American Ceramic Society》1997,80(6):1595-1598
Crystals of β-Ca2 SiO4 (space group P 121 / n 1) were examined by high-temperature powder X-ray diffractometry to determine the change in unit-cell dimensions with temperature up to 645°C. The temperature dependence of the principal expansion coefficients (αi ) found from the matrix algebra analysis was as follows: α1 = 20.492 × 10−6 + 16.490 × 10−9 ( T - 25)°C−1 , α2 = 7.494 × 10−6 + 5.168 × 10−9 ( T - 25)°C−1 , α3 =−0.842 × 10−6 − 1.497 × 10−9 ( T - 25)°C−1 . The expansion coefficient α1 , nearly along [302] was approximately 3 times α2 along the b -axis. Very small contraction (α3 ) occurred nearly along [ 01]. The volume changes upon martensitic transformations of β↔αL ' were very small, and the strain accommodation would be almost complete. This is consistent with the thermoelasticity. 相似文献
78.
Masanori Hirano Keisuke Ota Takaharu Ito 《Journal of the American Ceramic Society》2005,88(12):3303-3310
Anatase-type TiO2 powder containing sulfur with absorption in the visible region was directly formed as particles with crystallite in the range 15–88 nm by thermal hydrolysis of titanium(III) sulfate (Ti2 (SO4 )3 ) solution at 100°–240°C. Because of the presence of ammonium peroxodisulfate ((NH4 )2 S2 O8 ), the yield of anatase-type TiO2 from Ti2 (SO4 )3 solution was accelerated, and anatase with fine crystallite was formed. Anatase-type TiO2 doped with ZrO2 up to 9.8 mol% was directly precipitated as nanometer-sized particles from the acidic precursor solutions of Ti2 (SO4 )3 and zirconium sulfate in the presence and the absence of (NH4 )2 S2 O8 by simultaneous hydrolysis under hydrothermal conditions at 200°C. By doping ZrO2 into TiO2 and with increasing ZrO2 content, the crystallite size of anatase was decreased, and the anatase-to-rutile phase transformation was retarded as much as 200°C. The anatase-type structure of ZrO2 -doped TiO2 was maintained after heating at 1000°C for 1 h. The favorable effect of doping ZrO2 to anatase-type TiO2 on the photocatalytic activity was observed. 相似文献
79.
80.
S. Nakashima Y. Ikeda S. Hirose H. Nakamura T. Ito 《Journal of Materials Engineering and Performance》1992,1(2):211-218
Kawasaki Steel Corporation and Kawatetsu Mining Co., Ltd. have developed a new refining process to extract iron oxide from
iron ore to meet the increase in demand for iron oxide for high- grade hard ferrites. This article discusses the quality of
iron oxides and the characteristics of the hard ferrite magnets produced from them. 相似文献