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11.
Yasutada Suzuki Masatoshi Endo Jiye Jin Kenji Iwase Masaaki Iwatsuki 《Analytical sciences》2006,22(3):411-414
Tristimulus colorimetry using a digital still camera (DSC) as a colorimeter has been developed. A photograph of a sample and standard solutions was taken simultaneously with the DSC, and it was transferred to a PC. On the PC, the colors of the sample and of the standard solutions were analyzed and L* (brightness), a* (red-green component), and b* (yellow-blue component) values were determined with laboratory-made software. A dedicated light-box containing white-color LEDs as light source was made of white acrylic to make constant exposure at each photograph. Various settings of the DSC, such as exposure mode, white balance, and so on, that affect analytical figures, were studied with determination of iron with 1,10-phenanthroline. This method was successfully applied to the determinations of iron in a river water sample and of residual chlorine in tap water samples with N,N-diethylphenylenediamine (DPD). 相似文献
12.
Separation of fulvic acid from soil extracts based on ion-pair formation with a cationic surfactant.
Masami Fukushima Atsunori Kikuchi Kenji Tatsumi Fumiko Tanaka 《Analytical sciences》2006,22(2):229-233
A novel method for separating fulvic acid (FA) from soil extracts is proposed. The FA, defined as the acid-soluble fraction of an alkaline extract of soil, was separated based on the precipitation of an ion-pair with a cationic surfactant, such as domiphen bromide. The precipitate was dissolved in aqueous HCl to produce H+ -type FA and a surfactant chloride (SUR-Cl). SUR-Cl, in the aqueous solution, was removed by extraction with CHCl3. After the aqueous phase was passed through a cation-exchanger (H+ -type), H+ -type FA (FA-SUR) was obtained as a powder by lyophylization. The chemical characteristics of FA-SUR were compared with an FA sample separated according to the method of the International Humic Substances Society using a DAX-8 resin (FA-DAX). The oxygen content, O/C atomic ratio and total acidity of the FA-SUR were significantly larger than the corresponding values for FA-DAX. The solid-state CPMS 13C NMR spectra indicated that the higher oxygen content of the FA-SUR could be due to alcoholic hydroxyl groups and polysaccharides as well as carboxylic groups. These results show that FA-SUR is more polar and hydrophilic than FA-DAX. 相似文献
13.
Dedicated to Professor John C. Sheehan on the occasion of his sixty-fifth birthday. Chemical and biological modifications of bleomycin, an antitumor glycopeptide antibiotic, have been achieved by three procedures analogous to the modifications of penicillin. 相似文献
14.
Kenji Yokota Hideo Tomioka Teruyuki Ono Fumimasa Kuno 《Journal of polymer science. Part A, Polymer chemistry》1972,10(5):1335-1343
The sensitization effect of tertiary amines on the photopolymerization of methyl methacrylate was studied. N,N-Dimethylbenzylamine, triethylamine, and N,N-dimethylaniline increased the rate of polymerization in this order, but pyridine did not show any effect. A free-radical mechanism was confirmed by the tacticity of polymer, the retarding effect of hydroquinone, and the copolymer composition with styrene. On the basis of the detailed kinetics of the sensitized polymerization and the ultraviolet spectra of the reaction mixtures, a sensitization mechanism is proposed, in which the excited monomer and the amine form a complex and generate an initiating radical. 相似文献
15.
By the self-immolative asymmetric synthesis, optically pure key intermediate β-piperonyl-γ-lactone (R)-(+)- was found to be prepared in reasonable yield from the easily available chiral γ-lactone synthon () which had been also reported to give an antipode (S)-(-)-. The optically pure (R)-(+)- was shown to be converted successfully into several optically pure natural lignan lactones. 相似文献
16.
(+)-Steganacin was synthesized in a new and highly specific asymmetric pathway based on the novel application of chiral γ-lactone as a chiral synthon. By this synthesis the absolute stereochemistry of natural (?)-steganacin could be determined in unequivocal way. 相似文献
17.
Yoshinori Kadoma Takashi Toida Kenji Takeda Keikichi Uno Yoshio Iwakura 《Journal of polymer science. Part A, Polymer chemistry》1975,13(3):707-716
The polymerization of picryl (PMA), 2,4-dinitrophenyl (2,4-DNMA),2,6-dinitrophenyl (2,6-DNMA), 2-methyl-4,6-dinitrophenyl (MDNMA), and 2,6-dimethylphenyl methacrylates (DMMA) was carried out in benzene at 60°C. PMA, 2,6-DNMA, and MDNMA did not undergo radical homopolymerization, while 2,4-DNMA and DMMA did. The results suggest that the growing radical readily attacks the oxygen atom of the nitro group at the 2 position of the terminal phenyl group due to the steric effect of the substituent at the 6 position, resulting in chain termination. PMA formed a charge-transfer complex with 2-naphthyl methacrylate (NMA). The stoichiometric composition of this complex was shown to be 1:1 molar complex. PMA was readily copolymerized with NMA. The amount of solvent affected the composition of the copolymer obtained at a given same mole fraction in feed. The results suggest that charge-transfer interaction between the ester groups affects the copolymerization mechanism. 相似文献
18.
Toshiko Kido Katsumi Hashizume Kenji Soda Kozi Asada ‡ 《Photochemistry and photobiology》1978,28(4-5):729-732
Abstract— 2-Nitropropane dioxygenase (EC 1. 13. 11) of the yeast Hansenula mrakii catalyzes the oxygenative denitrification of 2-nitropropane as follows:
The enzyme is significantly inhibited by superoxide dismutase and various scavengers for superoxide such as cytochrome c , epinephrine, thiols and polyhydric phenols. The scavengers added to the reaction mixture were oxidized or reduced. The addition of superoxide dismutase and the omission of 2-nitropropane or oxygen prevented the oxidation and the reduction of the scavengers. The enzyme catalyzes the formation of nitrite from 2-nitropropane by KO2 added anaerobically.
One mole of NADH is bound per mole of the enzyme and predominantly the pro-R hydrogen of bound NADH is transferred to superoxide formed enzymatically or provided externally. The enzyme shows incomplete stereospecificity for hydrogen transfer from NADH. 相似文献
The enzyme is significantly inhibited by superoxide dismutase and various scavengers for superoxide such as cytochrome c , epinephrine, thiols and polyhydric phenols. The scavengers added to the reaction mixture were oxidized or reduced. The addition of superoxide dismutase and the omission of 2-nitropropane or oxygen prevented the oxidation and the reduction of the scavengers. The enzyme catalyzes the formation of nitrite from 2-nitropropane by KO
One mole of NADH is bound per mole of the enzyme and predominantly the pro-R hydrogen of bound NADH is transferred to superoxide formed enzymatically or provided externally. The enzyme shows incomplete stereospecificity for hydrogen transfer from NADH. 相似文献
19.
Koichiro Nakanishi Susumu Okazaki Kenji Ikari Hidekazu Touhara 《Chemical physics letters》1981,84(3):428-432
Monte Carlo calculations have been carried out for pure water and an infinitely dilute aqueous solution of methanol at 298.15 K at ordinary density by the Metropolis method in NTV ensemble. The hydration structure around methanol revealed by a graphic display technique indicates a structure-forming effect near the hydrophobic group. 相似文献
20.
Isao Watanabe Kusuo Nishiyama Kanetada Nagamine Kenji Kawano Ken-ichi Kumagai 《Hyperfine Interactions》1994,86(1):603-608
Zero field positive muon spin rotation method (
+SR) is applied on La2–x
Sr
x
CuO4 around forx=0.12 at which the high-T
c
superconductivity (SC) is suppressed. The magnetically ordered state of Cu-moments, which is not a spin glass state but an antiferromagnetic like state, appears below 15 K for 0.105x0.120. The magnetic phase boundary is very similar to the one of the La2–x
Ba
x
CuO4 in which the structural transition from the low temperature orthorhombic (LTO) phase to the low temperature tetragonal (LTT) phase is observed aroundx=0.12. The present study suggests that there is no big difference of the electronic state of the CuO2 plane between the La-Ba system and the La-Sr system and that the magnetic ordering of Cu-moments plays an important role for the suppression of the high-T
c
SC aroundx=0.12 in both of the systems, although the LTO-LTT structural transition has not been observed yet in the La-Sr system. 相似文献