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991.
Synthesis of cobalt nitrides has been tried in a supercritical nitrogen fluid at high pressure (about 10 GPa) and high temperature (about 1800 K) using diamond anvil cell and YAG laser heating system. We have succeeded to synthesize a single phase of the CFe2-type Co2N easily in a short time. This is the first synthesis by a simple reaction between the pure cobalt and pure nitrogen (supercritical fluid nitrogen). The cell parameters of the synthesized Co2N are a=4.662(9) Å, b=4.332(5) Å and c=2.749(9) Å, respectively. 相似文献
992.
Ryojun Sekine Nobuhiro Sato Tomochika Matsuyama Satoshi Akasaka Hirokazu Hasegawa 《Journal of polymer science. Part A, Polymer chemistry》2007,45(24):5916-5922
Polymer nanoporous materials with periodic cylindrical holes were fabricated from microphase‐separated structure of diblock copolymers consisting of a radiation‐crosslinking polymer and a radiation‐degrading polymer through simultaneous crosslinking and degradation by γ‐irradiation. A polybutadiene‐block‐poly(methyl methacrylate) (PB‐b‐PMMA) diblock copolymer film that self‐assembles into hexagonally packed poly(methyl methacrylate) cylinders in polybutadiene matrix was irradiated with γ‐rays. Solubility test, IR spectroscopy, and TEM and SEM observations for this copolymer film in comparison with a polystyrene‐block‐poly(methyl methacrylate) diblock copolymer film revealed that poly(methyl methacrylate) domains were removed by γ‐irradiation and succeeding solvent washing to form cylindrical holes within polybutadiene matrix, which was rigidified by radiation crosslinking. Thus, it was demonstrated that nanoporous materials can be prepared by γ‐irradiation, maintaining the original structure of PB‐b‐PMMA diblock copolymer film. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5916–5922, 2007 相似文献
993.
Hideto Tanoue Shinichiro Oke Hirofumi Takikawa Yushi Hasegawa Masao Kumagai Takeshi Ishikawa 《Applied Surface Science》2009,255(17):7780-7785
A new technique to etch a substrate as a pre-treatment prior to functional film deposition was developed using a filtered vacuum arc plasma. An Ar-dominated plasma beam was generated from filtered carbon arc plasma by introducing appropriate flow rate of Ar gas in a T-shape filtered arc deposition (T-FAD) system. The radiation spectra emitted from the filtered plasma beam in front of a substrate table were measured. The substrate was etched by the Ar-dominated plasma beam. The principal results are summarized as follows. At a high flow rate of Ar gas (50 ml/min), when the bias was applied to the substrate, the plasma was attracted toward the substrate table and the substrate was well etched without film formation on the substrate. Super hard alloy (WC), bearing steel (SUJ2), and Si wafer were etched by the Ar-dominated plasma beam. The etching rate was dependent on the kind of substrate. The roughness of the substrate increased, when the etching rate was high. A pulse bias etched the substrate without roughening the substrate surface excessively. 相似文献
994.
We here developed and evaluated a laser frequency control system which synchronizes the laser frequency to the resonance of target Ca + isotope ion whose having more than 8 GHz of isotope shift based on the Fringe Offset Lock method for simple operation of ICPMS-ILECS (Inductively Coupled Plasma Mass Spectrometry - Ion trap Laser Cooling Spectroscopy) The system fulfilled the minimum requirements of four slave lasers stability for Doppler cooling of Ca + ions. A performance of the system was evaluated by cooling 40Ca + ions with the stabilized slave lasers. All the stable even Ca + isotope ions were trapped and their fluorescence was observed by switching laser frequencies using the system. An odd calcium isotope 43Ca +cooling was also succeeded by the control system. 相似文献
995.
N. A. Inogamov V. V. Zhakhovsky N. Hasegawa M. Nishikino M. Yamagiwa M. Ishino M. B. Agranat S. I. Ashitkov A. Ya. Faenov V. A. Khokhlov D. K. Ilnitsky Yu. V. Petrov K. P. Migdal T. A. Pikuz S. Takayoshi T. Eyama N. Kakimoto T. Tomita M. Baba Y. Minami T. Suemoto T. Kawachi 《Applied physics. B, Lasers and optics》2015,119(3):413-419
996.
Abstract 2-Deoxy-d-arabino-hexose (1), 2-acetamido-2-deoxy-d-glucose (2), and 2-deoxy-2-trifluoroacetamido-d-glucose (3) were each treated with 1,1-dimethoxycyclohexane or 1,1-dibenzyloxycyclohexane in 1,4-dioxane in the presence of p-toluenesulfonic acid. The major products were the 1,1-dimethyl or 1,1-dibenzyl acetals (4-9) of 3,4:5,6-di-O-cyclohexylidene-2-deoxy-aldehydo-d-arabino-hexose, and of 2- (acylamino)-3,4:5,6-di-O-cyclohexylidene-2-deoxy-aldehydo-D-glucose. The dibenzyl acetal derivatives were converted, by hydro-genolysis, into the corresponding, acyclic aldehydes (10-12) in good yields. 相似文献
997.
Akira Hasegawa Eiji Seki Yushun Fujishima Koji Kigawa Makoto Kiso Hideharu Ishida 《Journal of carbohydrate chemistry》2013,32(3):371-385
Chemical coupling of biologically active derivatives of N-acetyl-muramoyl dipeptide with a derivative related to the nonreducing sub-unit of lipid A was carried out using acyl groups as a spacer. The products exhibited efficient antitumor activity, as well as strong, immunoadjuvant activity. 相似文献
998.
Akira Hasegawa Masayuki Ogawa Hideharu Ishida Makoto Kiso 《Journal of carbohydrate chemistry》2013,32(4):393-414
ABSTRACT Coupling of the primary hydroxyl group in the suitably protected 2-(trimethylsilyl)ethyl glycosides of D-glucopyranose (3), N-acetyl-D-glucosamine (7), N-acetyl-D-galactosamine (9), D-lactose (10), and N-acetylneuraminic acid (11), with methyl (methyl 5-acetamido-4, 7,8, 9-tetra-O-acetyl-3, 5-dideoxy-2-thio-D-glycero-α-D-galacto-2-nonulopyranosid)onate (12) as the glycosyl donor in acetonitrile in the presence of dimethyl(methylthio)sulfonium triflate (DMTST) as a glycosyl promoter and molecular sieves 3A, gave predominantly the corresponding α-glycosides 13, 15, 17, 25, and 29 of N-acetylneuraminic acid in 43-71% yields, respectively, together with the ß-glycosides (13-24%). 相似文献
999.
Akira Hasegawa Yuichi Hioki Makoto Kiso Hiroyuki Okumura Ichiro Azuma 《Journal of carbohydrate chemistry》2013,32(3):317-323
Abstract In the course of an investigation2 on the relationship between the immunoadjuvant activity and the structure of the carbohydrate moiety in N-acetylmuramoyl-L-alanyl-D-isoglutamine (MDP), which is the minimal, immunoadjuvant-active component of bacterial cell-wall peptidoglycan, we demonstrated that not only is restricted configuration of the sugar moiety important for the activity2 but also that chemical modifications3–5 of the functional groups in the carbohydrate moiety produce various, important effects on the manifestation of activity. It has been shown that lipophilic derivatives6–8 of MDP bearing the lipid moiety at C-6 of the sugar skeleton, or at the end of the peptide chain, have strong antitumor and anti-infection activities that are not for MDP itself. In addition, we have also observed that introduction3b,9,10 of lipophilic character at C-2 in muramoyl-L-alanyl-D-isoglutamine, or at C-6 in N-acetyl-6-amino-6-deoxy-muramoyl-L-alanyl-D-isoglutamine, causes potent antitumor activity based on the immune reaction, as well as strong, immunoadjuvant activities. 相似文献
1000.
Masayuki Hasegawa Takaaki Ito Mitsuyoshi Murata Ryo Yamauchi Koji Kato 《Journal of carbohydrate chemistry》2013,32(4-5):669-672
Abstract Isopropylidene acetals of carbohydrates are important as intermediates for the synthesis of other sugar derivatives. The isopropylidenation reaction is generally applied to only low molecular weight carbohydrates. However in 1982, we applied the reaction to a polysaccharide2 and demonstrated that (1→3)-β-D-glucan was isopropylidenated at the 4- and 6-hydroxyl groups of the D-glucose units. These results suggested that some chemical modification at the unprotected 2-hydroxyl groups might be possible. Consequently, (1→3)-β-D-glucomannan3,4 was derived from (1→3)-β-D-glucan through inversion of the 2-hydroxyl groups. 相似文献