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381.
Methane and fluoromethanes (CHnF4−n, 1 ≤ n ≤ 3) were subjected to an rf glow discharge plasma. All the fluoromethanes (including methane) polymerized in the plasma and formed thin films. The deposition rate of the fluoromethanes depended on their monomer structure: CH2F2, of which the F/H ratio is unity, showed the greatest deposition rate. The elimination of H and F atoms as H—F was found to be a key factor for the polymerization of fluoromethanes. The chemical composition of the polymerized film, measured with X-ray photoelectron spectroscopy and glow discharge emission spectroscopy, was also found to be strongly dependent on monomer structure. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2043–2050, 1998 相似文献
382.
Kazuo Suwa Yoshihiro Wada Yoshihiro Kikunaga Keitaro Morishita Akio Kishida Mitsuru Akashi 《Journal of polymer science. Part A, Polymer chemistry》1997,35(9):1763-1768
Pyrolysis of (N-α-isopropoxyethyl)isobutyramide, which was obtained by the reaction of isobutyramide, 2-propanol, and acetaldehyde in the presence of conc. sulfuric acid, produced N-vinylisobutyramide (NVIBA). The free radical polymerization of NVIBA was carried out in various solvents in the presence of a radical initiator. It was found that the polymerizability of NVIBA is similar to that of N-vinylacetamide. The resulting polyNVIBA showed a lower critical solution temperature (LCST) sharply at 39°C. Thermosensitive properties of polyNVIBA were investigated in comparison with poly(N-isopropylacrylamide). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1763–1768, 1997 相似文献
383.
Nobuyuki Sakamoto Tomoko Shioya Akio Kishida Mitsuru Akashi 《Macromolecular Symposia》1997,120(1):159-167
Poly(GEMA) or poly(GEMA)-sulfate grafted surfaces were prepared for the purpose of developing biomaterials with anticoagulant surfaces. Their functionalities were investigated as anticoagulant activity, proteins and cells adhesion activity, and complement activation activity. These results revealed that the adhesion of blood cells onto a GEMA-sulfate grafted surface was due to protein adsorption and that complement activation onto a GEMA-sulfate grafted surface was larger than that on a GEMA grafted surface. A GEMA-sulfate grafted surface, however, exhibited good anticoagulant activity. These functions seemed to be due to the specific functionality of the SO3 groups in a GEMA-sulfate. 相似文献
384.
Ming-Qing Chen Akio Kishida Mitsuru Akashi 《Journal of polymer science. Part A, Polymer chemistry》1996,34(11):2213-2220
Thermosensitive microspheres with 0.4–1.2 μm diameter consisting of a polystyrene core and poly(N-isopropylacrylamide) (polyNIPAAm) branches on their surfaces were prepared by the free radical polymerization of a polyNIPAAm macromonomer and styrene in ethanol. Electron spectroscopy for chemical analysis (ESCA) of the microsphere surface suggested that polyNIPAAm chains were favorably located on the surface of the microspheres. The morphology of the microspheres was observed by transmission electron micrograph (TEM) and the particle size of was estimated by submicron particle analyzer. The molecular weight of the polyNIPAAm macromonomer, the ratio of the macromonomer and styrene, and the polymerization temperature affected the particle size. Thermosensitive properties of polyNIPAAm-coated polystyrene microspheres were evaluated by the turbidity of their dispersion solutions and the hydrodynamic size of the miocrospheres. The transmittance in dispersion solutions changed clearly, similar to oligoNIPAAm and polyNIPAAm macromonomers. In addition, the particle size of microspheres decreased with rising temperature. These results were explained by the thermosensitivity of polyNIPAAm branches on the microsphere surface. © 1996 John Wiley & Sons, Inc. 相似文献
385.
Mariko Hagita 《Graphs and Combinatorics》1999,15(2):187-193
In this paper, we show that under some conditions the existence of a difference set in G implies the existence of another difference set with the same parameters in G′, where G and G′ are abelian groups of the same order. This explains why there are more difference sets in abelian groups of low exponent
and high rank than in those of high exponent and low rank.
Received: September 1, 1997 / Revised: March 24, 1998 相似文献
386.
Application of partial least square on quantitative analysis of L-, D-, and DL-tartaric acid by terahertz absorption spectra 总被引:1,自引:0,他引:1
Nishikiori R Yamaguchi M Takano K Enatsu T Tani M de Silva UC Kawashita N Takagi T Morimoto S Hangyo M Kawase M 《Chemical & pharmaceutical bulletin》2008,56(3):305-307
Absorption spectra of polycrystalline L-, D-, and DL-tartaric acid have been measured by terahertz time domain spectroscopy (THz-TDS). Different absorption bands are observed for DL-tartaric acid and its enantiomers (L- and D-tartaric acid). This result shows that the THz-TDS can be used for distinguishing between DL-tartaric acid and enantiomers (L- and D-tartaric acid). Moreover, partial least square (PLS) can be found to improve the quantitation of L-tartaric acid in L- and DL-tartaric acid mixture by THz-TDS. 相似文献
387.
Masako Nakagawa Manabu Ito Yuko Hasegawa Satoko Akashi Tohru Hino 《Tetrahedron letters》1984,25(35):3865-3868
We report the first total synthesis of (+)-tryptoquivaline 1a and of a key precursor, 2,3-dialkylquinazolinone 13b. 相似文献
388.
389.
Tsutomu Ishiwatari Satoshi Yoshida Mariko Morita Ikuko Seki Masaru Mitsuishi 《Journal of Polymer Science.Polymer Physics》1987,25(2):263-277
Association constants K for the complexation between various alkylviologens (methyl, propyl, butyl, pentyl, and hexyl) and indole derivatives (acetate and butyrate) have been determined. The order of K values indicates the important role of hydrophobic interactions in aiding the formation of charge transfer complexes. Influences of two kinds of polyelectrolytes; i.e., potassium polystyrenesulfonate (KPSS, anionic) and 3,3-ionene (cationic) on the K values were also examined. KPSS decreased the K value but, interestingly, yielded a minimum, and the K value increased at high KPSS concentrations. The influence of the type of alkylviologen on the K versus [KPSS] plots was successfully understood by a theory of substrate partitioning between bulk water and the environment of the polymer. 相似文献
390.
M. Katada H. Akashi T. Shibahara H. Sano 《Journal of Radioanalytical and Nuclear Chemistry》1990,145(2):143-149
Mixed-metal cubane-type clusters of [Mo3FeS4(NH3)9(H2O)Cl4 and [Mo3FeS4(H2O)10](pts)4.7H2O have been characterized by means of57Fe-Mössbauer spectroscopy. The Mössbauer parameters indicate that the oxidation states of iron in the cluster compounds are ascribed to +2.54 and +2.39, respectively. 相似文献