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101.
Atsushi Nakagawa Dominik Fenn Andreas Koschella Thomas Heinze Hiroshi Kamitakahara 《Journal of polymer science. Part A, Polymer chemistry》2011,49(23):4964-4976
This article describes a new synthesis strategy to prepare diblock copolymers as model compounds for industrially produced cellulose ethers exemplified with methylcellulose (MC). To elucidate a key structure for thermoreversible gelation of MC, five regioselectively methylated celluloses 1 – 5 (236, 23, 26, 3, and 6 MC), five corresponding methyl‐β‐D‐glucopyranosyl‐(1→4)‐cellulosides 6 – 10 , and five equiv methyl‐β‐D‐glucopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→4)‐cellulosides 11 – 15 were synthesized for the first time via combination of the glycosyl trichloroacetimidate method and the acid‐catalyzed methanolysis method. The structure of compounds 1 – 15 was confirmed by means of NMR spectroscopy and MALDI‐TOF MS. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
102.
We investigated the details of sucrose and L-α-alanine radicals produced by heavy-ion irradiation with various linear energy
transfer (LET) values. The impact of the heavy ions on samples produced stable free radicals, which were analyzed by electron
paramagnetic resonance (EPR). The spectral patterns obtained were similar among those for the irradiation of carbon (C), neon
(Ne), silicon (Si), and argon (Ar) ions. The radical production of irradiated sucrose and alanine samples showed a linear
relation with the absorbed dose. The total spin concentration obtained by heavy-ion irradiation decreases as logarithmic function
of the LET. Quantitative EPR analysis showed that the production of sucrose and alanine radicals depended on both the ion
species and the LET values under the same dose. Moreover, the radical-production cross sections for sucrose and alanine irradiated
with C ions (290 MeV/u) were about 1.3 · 10−8 and about 3.0 · 10−9 μm2, respectively. The results of the cross section suggest that each molecule becomes a stable radical with the interaction
of several particles.
Authors' address: Kouichi Nakagawa, Radioisotope Research Center, Fukushima Medical University, 1 Hikari-gaoka, Fukushima
960-1295, Japan 相似文献
103.
104.
Y. Takeuchi F. Yamamoto T. Konaka K. Nakagawa 《Journal of Polymer Science.Polymer Physics》1986,24(5):1067-1077
In the production of ultrahigh-modulus (45–60 GPa) polyoxymethylene (POM) by microwave heating drawing, ultradrawing to draw ratios over 20 causes formation of numerous voids and radicals. The volume fraction of the internal voids is proportional to the drawing-induced radical concentration. On the basis of the idea that the rupture of taut tie-molecules (TTM) is responsible for void and radical formation, the relationship between the fraction of tiemolecules that are taut and the fraction that are ruptured is discussed by assuming both a Takayanagi structure model and the normal distribution of the tie-molecule lengths. The results indicate that longer tie-molecules are successively converted to TTM's followed by ruptures of shorter TTM's in the ultradrawing process; a small variance in the tie-molecule length distribution is effective for increasing TTM's without void formation. The maximum value of the volume fraction of taut tie-molecules for highly oriented POM tubes is estimated to be about 0.5. 相似文献
105.
L. Gillo S. E. Golbreich T. Nagoshi I. Nakagawa C. S. Piper W. C. Campbell Marion I. Hanna L. Palfray C. Rocchi R. del Monte R. Lechner M. Roß L. A. Ynalvez H. Lecoq Th. A. G. Haanappel Thérèse Jullig J. Barbière A. Lecco L. Lilic und P. M. Heertjes 《Fresenius' Journal of Analytical Chemistry》1943,125(3-4):133-137
Ohne Zusammenfassung 相似文献
106.
107.
108.
M Uchida S Morita M Chihiro T Kanbe K Yamasaki Y Yabuuchi K Nakagawa 《Chemical & pharmaceutical bulletin》1989,37(6):1517-1523
Many 8-[(2-benzimidazolyl)sulfinyl]-5,6,7,8-tetrahydroquinolines were synthesized and examined for their (H+ + K+) adenosine triphosphatase ATPase-inhibitory and antisecretory activities. These sulfinyl compounds could be considered to be rigid analogues of the 2-[(2-pyridyl)methylsulfinyl]benzimidazole class of antisecretory agents. All the compounds tested were potent inhibitors of (H+ + K+)ATPase. Most of the compounds also inhibited histamine-induced gastric acid secretion in rats. Among them, 8-[(5-fluoro-2-benzimidazolyl)sulfinyl]-3-methyl-5,6,7,8-tetrahydroqu inoline (XIVm) was found to have the most potent activity. The structure-activity relationships are discussed. 相似文献
109.