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81.
A holographic system has been developed to visualize a three-dimensional fluid flow. The system consists principally of a thermoplastic film, a monochrome video camera, a microcomputer with image-processing capability and a printer. The system makes it possible to measure a slow flow. Two examples of such, the bimodal and mixed-mode convection flows within a Bénard cell, are presented. 相似文献
82.
83.
T Nakagawa K Izawa S Yagi A Shibukawa H Tanaka T Tashima M Imai 《Chemical & pharmaceutical bulletin》1989,37(9):2463-2466
When a 10% aqueous solution of glutaraldehyde (GA) was alkalized to pH 8.5 in borate buffer solution and heated at 60 degrees C, the ultraviolet spectrum of GA solution showed two distinct absorption maxima. The one at 280 nm with a weak absorbance ascribable to the C = O bond in the aldehyde group shifted to near 300 nm after 50 min with a slight increase in its intensity. Another maximum at 235 nm with a strong absorbance was ascribable to the C = C bond of the alpha,beta-unsaturated aldehyde group which was formed by aldol condensation reaction of GA monomer, and its absorbance increased markedly with increasing reaction time. The high performance liquid chromatography (HPLC) analysis with detection at 235 nm indicated that several GA oligomers were formed by the alkali treatment and their concentrations increased. The cross-linking ability of these oligomers was examined by immobilizing enzymes (alcohol dehydrogenase (ADH), glutamate dehydrogenase (GLDH] to an aminated polymer gel matrix by reaction with the treated GA solution. The enzyme activities increased with increasing concentration of GA oligomers. Then, the GA oligomers were isolated and used as the cross-linking agent. The activities of ADH and GLDH were 4-fold and 13-fold higher, respectively, than those obtained by using untreated GA solution, while the total amounts of immobilized enzymes were almost unchanged. These results suggest that GA oligomers may act as cross-linkers in a manner different from the generally accepted Schiff base formation reaction; a possible mechanism may involve addition reaction of an amino group to the double bond in the aldol condensate of GA.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
84.
Keita?Suzuki Jun-ichi?Oku Kenichi?Izawa Hiro-Fumi?OkabayashiEmail author Isao?Noda Charmian?J.?O’Connor 《Colloid and polymer science》2004,283(3):306-316
The two-step polymerization process of two well-defined polymeric silane coupling agents, triethoxysilyl-terminated polystyrene with molecular weights equal to 2400 [TESi-PS (2400)] and 8000 [TESi-PS (8000)], catalyzed by 0.1 mol/kg CH3SO3H, was traced as a function of reaction time using gel-permeation chromatography (GPC). Two sets of GPC traces, collected during the condensation, were then converted to two-dimensional (2D) correlation spectra by using generalized 2D correlation theory. The 2D correlation spectra elucidated details of the aggregate–aggregate correlations [in particular, the difference between the correlations of TESi-PS (2400) and TESi-PS (8000)], thus demonstrating the effect of aggregation on the polymerization. 相似文献
85.
Shigekazu Kumakura Satoshi Shiraishi Masaru Izawa Mitsuyasu Hanamura 《International journal of quantum chemistry》1992,41(6):785-792
Second-order multiconfigurational self-consistent field (MCSCF ) calculation has been programmed on the basis of CNDO /INDO molecular orbital bases, in which the configuration space employed is restricted within pair-excitations. Test calculations have been carried out for 17 small molecules. All the MCSCF ground states of these molecules have been successfully converged to their respective optimal states by employing a simple weighting scheme. This procedure provides a great savings in computer time. The MCSCF calculation on azetidine required only 27 min on a HITAC M-680H. The MCSCF energies of HF, F2, and BH show improved behaviors up to large atomic distances (~7au). 相似文献
86.
Shin-Ichi Takahashi Tetsuya Fujimoto Basu M. Barua Takeaki Miyamoto Hiroshi Inagaki 《Journal of polymer science. Part A, Polymer chemistry》1986,24(11):2981-2993
13C-NMR spectra of trityl cellulose (Tr-Cell), tosyl cellulose (Ts-Cell), cellulose S-methyl xanthate (Cell-M-Xan), and cellulose formate (CF) in dimethylsulfoxide-d6 were analyzed at 50.4 MHz. It was found that the distribution of substituents in the anhydroglucose units of these cellulose derivatives can be estimated from their ring carbon spectra. The results showed that (i) in Tr-Cell having degree of substitution (DS) lower than 1, the hydroxyl groups at C-6 carbon position are selectively tritylated, (ii) in the case of Ts-Cell, the difference in the relative DS value among three different types of hydroxyl groups is not large, although the relative reactivities of hydroxyl groups toward tosylation decrease in the order C-6 > C-2 > C-3, (iii) in Cell-M-Xan, the hydroxyl groups at C-3 carbon position are mainly substituted, and (iv) the ease of formylation is C-6 > C-2 > C-3. The 100.8 MHz 13C-NMR spectra of O-methyl cellulose (MC) revealed that the reactivity order in commercial MC prepared from alkali cellulose is C-6 ? C-2 > C-3. Concerning MC, its water solubility was also discussed in terms of the distribution of substituents along the cellulose chain. 相似文献
87.
88.
Yokoyama T Matsukado Y Uchida A Motomura Y Watanabe K Izawa E 《Journal of colloid and interface science》2001,233(1):112-116
The behavior of AuCl(4)(-) ions during the formation of aluminum hydroxide at pH 6 was examined. With an increase in NaCl concentration, the content of gold taken up by aluminum hydroxide decreased, suggesting that chloro-hydroxy complexes of Au(III) ion were taken up due to the formation of Al-O-Au bonds. It was found unexpectedly that the Au(III) ions taken up were spontaneously reduced to elemental gold without addition of a specific reducing reagent and then colloidal gold particles were formed. The mechanisms for the uptake of Au(III) ions by aluminum hydroxide and for their spontaneous reduction are discussed. Copyright 2001 Academic Press. 相似文献
89.
Toshio Ito Nobuya Tomiyoshi Koki Nakamura Shizuo Azuma Makoto Izawa Fumio Maruyama Mitsutoshi Yanagiya Haruhisa Shirahama Takeshi Matsumoto 《Tetrahedron》1984,40(1):241-255
The total synthesis of dl-coriolin has been achieved in a stereoselective way. The key tricyclic intermediate was synthesized from dicyclopentadiene through a route which involved an SN2 reaction at a neopentylic position. 相似文献
90.
Sequential injection analysis (SIA) was applied to multi-gas monitoring for atmospheric analysis. HONO, NO2 or NO was collected in an individual diffusion scrubber in which the channel array was filled with either HCl or triethanolamine solution. All analytes were collected in the form of nitrite ions in the scrubber, and were transferred via a 12-port selection valve into a 2.5-ml syringe. The reagent, 3-amino-1,5-naphthalenedisulfonic acid (C-acid) solution was subsequently introduced into the syringe, and inter-mixed with the nitrite sample, whereafter the mixed solution was transferred to a heated reactor and held for 3 min at 100 °C. After that, the sample/reagent solution was returned to the syringe and alkalinized. Then, the final solution was analyzed using a homemade fluorescence detector. Atmospheric HONO, NO2 and NO were successfully monitored 3 or 4 times/h. The limits of detection were 0.22, 0.28 and 0.35 ppbv for HONO, NO2 and NO, respectively. It was demonstrated for the first time that SIA is a good tool for multi-gas atmospheric analysis. These nitrogen-oxygen compounds are interconvertible, and the simultaneous measurement of these gases is important. Especially, HONO is a source of OH radicals which contribute greatly to atmospheric pollution, and indeed atmospheric chemistry. This method allows the three gases to be measured using one system. The NO2 and NO data obtained by SIA was compared with those obtained using chemiluminescence instrument. SIA has been successfully applied to atmospheric measurements. Interestingly, it was observed that HONO levels rose toward the end of periods of rain. 相似文献