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81.
Ken-Ichi Okamoto Nozomu Tanihara Hitoshi Watanabe Kazuhiro Tanaka Hidetoshi Kita Asumaru Nakamura Yoshihiro Kusuki Kanji Nakagawa 《Journal of Polymer Science.Polymer Physics》1992,30(11):1223-1231
Sorption and diffusion of water vapor are investigated gravimetrically for polyimide films. The activity dependence of the solubility and diffusion coefficients, S and D, respectively, is classified under four types: (1) constant S and D type, (2) dual-mode sorption and transport type, (3) dual-mode type followed by a deviation due to a plasticization effect at high vapor activity, and (4) constant S and D type followed by a deviation due to water cluster formation at high activity. For the dual-mode type, the Henry's law component is much larger than the Langmuir component except at low activity, and therefore deviation in behavior from the first type is small. S is larger for polyimides with higher content of polar groups such as carbonyl, carboxyl, and sulfonyl. D is larger for polyimides with a higher fraction of free space, with some exceptions. The polyimide from 3,3′,4,4′-biphenyltetracarboxylic dianhydride and dimethyl-3,7-diaminodibenzothiophene-5, 5-dioxide belongs to the third type and displays both large S and large D. The polyimide from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 4,4′-oxydianiline belongs to the fourth type, and has the largest D but rather small S because of the hydrophobic C(CF3)2 groups. © 1992 John Wiley & Sons, Inc. 相似文献
82.
Keiichi Moriya Shigekazu Nakagawa Shinichi Yano Meisetsu Kajiwara 《Liquid crystals》1995,18(6):919-921
(S)-Hexakis(4-(4'-(6-methyl)octyloxy)biphenoxy)cyclotriphosphazene (SMOCP) was synthesized in a search for new ferroelectric liquid crystalline compounds. We found an enantiotropic ferroelectric smectic C* phase between 419 and 441 K in SMOCP by using polarizing microscopy and DSC measurements. The spontaneous polarization was estimated to be -130.5 μCm-2 at 437.6 K, several times larger than that of DOBAMBC ((S)-2-methylbutyl 4-(4'-decyloxybenzylidene)aminocinnamate. 相似文献
83.
Kazuhisa Hiratani Isao Nozawa Tsutomu Nakagawa Sumio Yamada 《Journal of membrane science》1982,12(2):207-215
The effects of acid and cation concentration on the uphill transport rates of cations and selectivities through chloroform liquid membrane by noncyclic polyether ionophores, which are pentaethylene glycol derivatives containing both 8-quinolyt and o-carboxylphenyl terminal groups, have been demonstrated. Using sulfuric, oxalic, or polyphosphoric acid in aqueous solution, the initial transport rates and the amount of cation transported by the ionophores after two days were larger than those using hydrochloric or nitric acid. Using picric acid, the amount of cation transported decreased greatly. It was confirmed that it decreased where an acid could easily be counter-transported by the ionophore through liquid membranes. On the other hand, it was found that the rates, amounts of cation transported, and selectivities, change with the changing of the cation concentration in the aqueous solutions. When the cation concentration in both aqueous solutions is high enough compared with the pH gradient between the two aqueous solutions, the rate, amount, and selectivity of the ionophore for potassium ion increases compared with when the cation concentration is low. 相似文献
84.
Synthesis of naphtho-tri-t-butyltrisdehydro[16]annulene containing a hexapentaene and an acetylene units has been described. It was found that the [16]annulene is less stable and the paratropicity is much stronger as compared with previously reported isomeric naphtho[16]-annulene containing a diacetylene and a butatriene linkage. 相似文献
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89.
H. Hiroyoshi H. Yamauchi Y. Yamaguchi H. Yamamoto Y. Nakagawa M. Sagawa 《Solid State Communications》1985,54(1):41-43
Magnetization measurements have been made on a Sm2Fe14B single crystal in magnetic fields up to 140 kOe. The easy direction of the magnetization lies along [100] in the tetragonal structure P42/mnm. Magnetic anisotropy energies at 290K along [110] and [001] have been estimated to be 5.8×106 and 1.1×108 erg/cm3, respectively, both becoming much larger at lower temperature. No evidence of the spin canting of Nd2Fe14B type is observed even at 4.2K. 相似文献
90.
Jun Nakagawa Richard F. Wormsbecher David O. Harris 《Journal of Molecular Spectroscopy》1983,97(1):37-64
Single-mode cw dye laser excitation spectra of the (0, 00, 0)-(0, 00, 0), (1, 00, 0)-(1, 00, 0), (0, 11, 0)-(0, 11, 0) bands of the 611- to 607-nm system of SrOH and SrOD were observed and assigned. The spectrum is consistent with a 2Σ-2Σ system where the molecule is linear in both electronic states. The rotational analysis is obtained by measuring P-R separations in the excitation spectrum. A technique which greatly aided in the spectral assignment that utilizes a monochromator as a bandpass filter in obtaining excitation spectra is described. A new spin-rotation constant, γ(+) - γ(?), was found necessary to fit the l-type doubling of the (0, 11, 0) mode in B2Σ+ of SrOH. This new constant is assumed to arise from two vibronic states, split by Renner-Teller interaction, of the (0, 11, 0) mode of A2Π. From a perturbation treatment of this electronic interaction, ?ω2 of the (0, 11, 0) mode of A2Π was found to be 14 cm?1. The linear structure of SrOH and SrOD in both electronic states is consistent with the model, in the one-electron approximation, in that the transition involves the promotion of the unpaired 5s to the 5p orbital localized on the strontium. 相似文献