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41.
Naomi Warashina Masahiro Tsuchiya Kaori Ishimaru Takakazu Kojima 《Journal of Thermal Analysis and Calorimetry》2011,105(2):473-477
Imbalance condensation of diaminophenylbenzimidazole, DAPBI, with terephthaloyl chloride, TPC was conducted for the purpose
of synthesis of macromonomers, expected to be used in syntheses of aromatic polyamides with structural regularities. The products
are soluble in dimethylsulfoxide—d6, and their 1H NMR spectra indicate that all the products are carboxyl-terminated. The
signal of carboxyphenyl linked to chain ends is different from that of terephthaloyl in the 1H NMR spectra. By use of the
ratio of the signal intensity of the former to that of the latter, the number-average degree of polymerization, DP
NMR is determined. With the mole ratio in feed, DP
NMR of the product increases. The TG thermograms of the products are a multistage one. Each stage is classified by temperature
and mass loss at an inflection point. Mass loss of each stage classified by temperature at an inflection point corresponds
to mass fraction of an aromatic amide with a characteristic degree of polymerization, DP, and that is, the DP distribution of the products is roughly estimated from the TG thermograms. The DP distribution of macromonomers influences performance of aromatic polyamides with structural regularities, derived from the
macromonomers. The convenient estimation method of DP distribution by TG is useful in industries of high-performance polymers. To the knowledge, such convenient technique has
never reported. 相似文献
42.
43.
Formation of Superhydrophobic Alumina Coating Films with High Transparency on Polymer Substrates by the Sol-Gel Method 总被引:6,自引:0,他引:6
Kiyoharu Tadanaga Kaori Kitamuro Atsunori Matsuda Tsutomu Minami 《Journal of Sol-Gel Science and Technology》2003,26(1-3):705-708
Transparent, superhydrophobic coating films have been prepared on polymer substrates at low temperatures through the sol-gel method. Al2O3 gel films were prepared on poly(ethylene terephthalate) substrates from Al(O-sec-C4H9)3 chemically modified with ethyl acetoacetate. A small roughness of about 20–50 nm was found to form on the surface of the Al2O3 gel films dried at room temperature and then immersed in hot water at 60°C. The electron diffraction measurements have shown that this roughened surface consists of pseudoboehmite nanocrystals. The coating of hydrolyzed fluoroalkyltrimethoxysilane on the Al2O3 gel films with the small roughness produced transparent, superhydrophobic films with contact angle for water larger than 150°. 相似文献
44.
Fluorescence resonance energy transfer by quencher adsorption into hydrogels containing fluorophores
Kaori Okawa Takashi Miyata Tadashi Uragami 《Journal of Polymer Science.Polymer Physics》2006,44(22):3245-3252
We synthesized anionic hydrogels containing fluorophores and investigated the adsorption of a cationic quencher having an amino group into hydrogels by fluorescence resonance energy transfer (FRET). FRET from the fluorophore to the quencher in hydrogels was examined by fluorescence intensity and fluorescence decay using a fluorescence spectrophotometer and femtosecond laser spectroscopy. The fluorescence intensity of the fluorophore‐containing hydrogels decreased rapidly with increasing amounts of adsorbed cationic quencher. The fluorescence emission of the fluorophore in the quencher‐adsorbed hydrogels containing fluorophores decayed more rapidly than that of the original hydrogels. The aforementioned result indicates that the fluorescence of the fluorophore‐containing hydrogels is quenched due to FRET from the fluorophore to the quencher as the cationic quenchers can approach the fluorophores in hydrogels by electrostatic interactions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3245–3252, 2006 相似文献
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48.
Masashi Wakamatsu 《Nuclear Physics A》1979,329(3):381-406
The effects of the Δ(3-3) resonance components on the binding energy of 4He are studied within the framework of reaction matrix theory. In this approach, the Δ -configurations in 4He are introduced in terms of the NΔ transition potential by solving the reaction matrix equation and thus it goes beyond perturbation theory with the NΔ transition potential. Not only the two-body cluster energy but also the three-body cluster energy containing Δ-configurations are calculated. 相似文献
49.
Ijima Y Matoishi K Terao Y Doi N Yanagawa H Ohta H 《Chemical communications (Cambridge, England)》2005,(7):877-879
The introduction of two mutations (G74C/C188S) based on the estimated reaction mechanism resulted in the inversion of enantioselectivity of arylmalonate decarboxylase, which catalyses the asymmetric decarboxylation of arylmethylmalonate to give optically active arylpropionate. 相似文献
50.
With a particular view to gaining a real understanding of the quark degrees of freedom in nuclei, we propose a simple model for nucleon-nucleon interactions within the framework of the quark cluster theory, which simultaneously incorporates the quark- and gluon-exchange mechanism at short distance and the meson-exchange mechanism at long and intermediate distances. It is shown to reproduce the experimental NN phase shifts and the deuteron properties fairly well. The model is then applied to a study of the electromagnetic properties of the two-baryon system, by putting particular emphasis upon the relation with conventional nuclear theory. The present study shows how the quark degrees of freedom, which should manifest themselves at high momentum transfer, are concealed in the conventional treatment of the two-nucleon problem as long as we observe low momentum transfer phenomena only. 相似文献