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171.
Takako Nakamura Tsuguyori Ohana Masahiro Suzuki Masatou Ishihara Akihiro Tanaka Yoshinori Koga 《Surface science》2005,580(1-3):101-106
Photolysis of perfluoroazooctane with diamond-like carbon (DLC) films led to the surface modification to introduce perfluorooctyl functional groups, confirmed by means of FT-IR, XPS, Raman and TOF-SIMS measurements. The DLC films modified with fluorine moieties showed reduction of the surface energy evaluated by contact angle to water, as compared with pristine DLC film. The contact angle of chemically modified DLC film is 105°, comparable to that of polytetrafluoroethylene (PTFE). By monitoring with XPS, we found that the results on the value of fluorine/carbon ratio of fluorinated DLC films depending on irradiation time are consistent with those of contact angle. Chemical modification of DLC films with perfluorooctyl functionalities also led to improvement of their frictional properties. The friction coefficient of the modified film is 0.05 under vacuum condition, whereas that of the pristine film shows very high value (>1). 相似文献
172.
Kei-Ichi Kitahara Yuji Noguchi Satoshi Itoh Nobunao Chiba Tasuku Tohyama Kunio Nagashima Takako Hanada Isao Yoshihama Sadao Arai 《Journal of chromatography. A》2009,1216(44):7415-7421
Using an HPLC column packed with monodispersed vinylbenzeneboronic acid–divinylbenzene (V–D) copolymer resins, the elution behaviors of the mono- and disaccharides were studied under different pH mobile phases. The monodispersed V–D copolymer resins were prepared by the copolymerization of 4-vinylbenzeneboronic acid and divinylbenzene in the presence of template silica gel particles (particle size: 5 μm; pore size: 10 nm), followed by dissolution of the template silica gel using a NaOH solution. Similarly, styrene–divinylbenzene (S–D) copolymer resins as the control resins were also synthesized. The transmission electron micrographs of these polymer resins revealed a good monodispersity. The complexation behavior of the saccharides was evaluated by comparison of the peak area eluted through the V–D column for that through the S–D column. Four aldopentoses (d-ribose, d-arabinose, d-xylose, and d-lyxose) and four aldohexoses (d-glucose, d-mannose, d-galactose, and d-talose) were retained completely at pH 11.9. Especially, ribose and talose were totally retained even under acidic and neutral conditions. For the disaccharides, unlike sucrose and maltose, palatinose was completely retained in basic mobile phases. 相似文献
173.
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175.
Masu H Mizutani I Kato T Azumaya I Yamaguchi K Kishikawa K Kohmoto S 《The Journal of organic chemistry》2006,71(21):8037-8044
A circular dichroism (CD) spectral study on chiral aromatic chain imides possessing anthracene and naphthalene moieties with bulky N substituents showed that their helical chirality based on folding remained for a reasonably long time without racemization in solution. Racemization due to conformational equilibration occurred very slowly, requiring over 1 week at ambient temperature. Their CD spectra both in solution and in the solid state gave similar CD signals, suggesting retention of helicity observed in the solid state even after dissolving. As an application of this novel chiral folding of aromatic chain imides, a chiral photochromic system was investigated based on the photo [4 + 4] cycloaddition and its thermal cycloreversion of an anthracene-naphthalene system. The foldamer possessing an anthracene moiety in the center connected with two naphthalene moieties below and above it by iminodicarbonyl linkers was prepared for this purpose. Induced CD was observed for the foldamer with (S)-1-(1-naphthyl)ethyl substituents at the imide nitrogen atoms. Chiral photochromic cycles were monitored by CD spectral measurement. 相似文献
176.
Yoshiaki Yuguchi Takako Kumagai Min Wu Takahiro Hirotsu Jun Hosokawa 《Cellulose (London, England)》2004,11(2):203-208
Xyloglucan has a cellulose backbone with branched (16)--xylose or (12)--galactoxylose as a side chain. Its aqueous solution yields a gel by adding alcohol. The gel structure of xyloglucan ID various kinds of mono- or polyhydric alcohol/water systems was studied by small-angle X-ray scattering (SAXS). The gelation behavior ID strongly dependent on the type of alcohol. The SAXS from gel with monohydric alcohols indicated that the xyloglucan chains caused random aggregation, as expressed with a Debye–Bueche type scattering function. The type of alcohol added was correlated with the size of the inhomogeneity, as evaluated by SAXS results. The gelation with polyhydric alcohols resulted ID less association, which occurred as side-by-side association with a few xyloglucan chains, rather than as random aggregation. 相似文献
177.
178.
Enoki T Tanaka K Watanabe T Oya T Sakiyama T Takeoka Y Ito K Wang G Annaka M Hara K Du R Chuang J Wasserman K Grosberg AYu Masamune S Tanaka T 《Physical review letters》2000,85(23):5000-5003
We report an experimental realization of a gel system in which frustrations exist and can be minimized, thus meeting two crucial criteria predicted to enable memory of conformations in polymers. The gels consist of a thermosensitive major monomer component and two minor components. One minor component is positively charged and will form complexes around negatively charged target molecules placed in solution. The complexes can be imprinted into the gel by then cross-linking the second minor component, which will form cross-links additional to those in the major polymer matrix. The complexes are destroyed and reformed upon swelling and reshrinking of the gels, showing that memorization has been achieved. 相似文献
179.
Masako Nakagawa Takako Maruyama Kazuyuki Hirakoso Tohru Hino 《Tetrahedron letters》1980,21(50):4839-4842
Oxytryptamine was converted to kynurenamine , benzo-oxazinone , and 3-hydroxy derivative b in NaOH-MeOH in the presence of oxygen, whereas undergoes N,N′-transacylation to give the isomeric product in argon atmosphere. 相似文献
180.