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21.
Yan Yin Otoo Yamada Shunsuke Hayashi Kazuhiro Tanaka Hidetoshi Kita Ken‐Ichi Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2006,44(12):3751-3762
A series of branched/crosslinked sulfonated polyimide (B/C‐SPI) membranes were prepared and evaluated as proton‐conducting ionomers based on the new concept of in situ crosslinking from sulfonated polyimide (SPI) oligomers and triamine monomers. Chemical branching and crosslinking in SPI oligomers with 1,3,5‐tris(4‐aminophenoxy)benzene as a crosslinker gave the polymer membranes very good water stability and mechanical properties under an accelerated aging treatment in water at 130 °C, despite their high ion‐exchange capacity (2.2–2.6 mequiv g?1). The resulting polymer electrolytes displayed high proton conductivities of 0.2–0.3 S cm?1 at 120 °C in water and reasonably high conductivities of 0.02–0.03 S cm?1 at 50% relative humidity. In a single H2/O2 fuel‐cell system at 90 °C, they exhibited high fuel‐cell performances comparable to those of Nafion 112. The B/C‐SPI membranes also displayed good performances in a direct methanol fuel cell with methanol concentrations as high as 50 wt % that were superior to those of Nafion 112. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3751–3762, 2006 相似文献
22.
V. N. Manuilov T. Idehara M. Kamada T. Hayashi La Agusu T. Kanemaki K. Yatsui Wiehua Jiang 《International Journal of Infrared and Millimeter Waves》2006,27(9):1183-1193
High power Large Orbit Gyrotron (LOG) [1] is now under development at FIR FU. First version of this device was recently manufactured
and then assembled with power supply ETIGO-IV [2]. Results of preliminary tests of electron-optic system are presented. The
conditions when stableflat form of current pulse realized are discussed. Analytical estimations of cathode-anode distance
to achieve small influence of cathode plasma during high voltage (HV) pulse are performed.
Two new electron gun versions with decreased influence of the cathode plasma on its impedance and pulse form are suggested
and optimized. New optimal magnetic field distributions are found. First gun has quiasi-flat cathode configuration near the
anode diaphragm and provides operating current about 60 A. Second one uses blade cathode with operating current about 30 A.
Beam quality for both guns is suitable for LOG operation. 相似文献
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Spin-lattice relaxation mechanisms in kaolinite have been reinvestigated by magic-angle spinning (MAS) of the sample. MAS is useful to distinguish between relaxation mechanisms: the direct relaxation rate caused by the dipole-dipole interaction with electron spins is not affected by spinning while the spin diffusion-assisted relaxation rate is. Spin diffusion plays a dominant role in 1H relaxation. MAS causes only a slight change in the relaxation behavior, because the dipolar coupling between 1H spins is strong. 29Si relaxes directly through the dipole-dipole interaction with electron spins under spinning conditions higher than 2 kHz. A spin diffusion effect has been clearly observed in the 29Si relaxation of relatively pure samples under static and slow-spinning conditions. 27Al relaxes through three mechanisms: phonon-coupled quadrupole interaction, spin diffusion and dipole-dipole interaction with electron spins. The first mechanism is dominant, while the last is negligibly small. Spin diffusion between 27Al spins is suppressed completely at a spinning rate of 2.5 kHz. We have analyzed the relaxation behavior theoretically and discussed quantitatively. Concentrations of paramagnetic impurities, electron spin-lattice relaxation times and spin diffusion rates have been estimated. 相似文献
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By means of exponential laws we show a Bianchi Type I model of the universe where we define overall deceleration and Hubble's parameters that have constant values. We employ a convenient relation for defining the radius of the universe. Pressure and density have constant values, too. 相似文献
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Hanaoka T Hayashi H Tago T Kishida M Wakabayashi K 《Journal of colloid and interface science》2001,235(2):235-240
We investigated the in situ immobilization of ultrafine particles synthesized in a water/oil (w/o) microemulsion to silica for its possible application to supported metal catalysts. ZnS particles immobilized to silica by the ME method were consistent with those synthesized in a w/o microemulsion. Therefore, ZnS particles in a w/o microemulsion could be immobilized to silica without aggregation by this method. The relationship between the method of synthesizing Rh ultrafine particles in a w/o microemulsion and the diameter and diameter distribution of Rh particles immobilized to silica was studied. Rh-SiO(2) catalysts with a sharp diameter distribution could be prepared by immobilizing Rh-hydrazine complex particles because these complex particles would be very stable in a w/o microemulsion. The Rh particle diameters of Rh-SiO(2) catalysts prepared by changing the amount of silica produced were almost identical. Accordingly, the Rh particle diameter of Rh-SiO(2) catalysts could be controlled independently of Rh content by the ME method. Copyright 2001 Academic Press. 相似文献
30.
Shizuko Eguchi Mitsuru Nakayama Shûichi Hayashi 《Journal of mass spectrometry : JMS》1976,11(6):574-581
The doubly charged ion mass spectra of anhydropisatin, 4-methoxyanhydropisatin, 3, 8, 9-trimethoxypterocarpen and 3, 4, 8, 9-tetramethoxypterocarpen were determined, and the fragmentation was explained by assuming that the paired electrons were partially localized in the fragmentations and by comparing the spectra with that of 3-(CD3)-anhydropisatin. Conventional mass spectra of these compounds were very simple, but the doubly charged ion spectra were sufficiently characteristic for the reliable identification. 相似文献