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81.
Urata H Sasaki R Morita H Kusumoto M Ogawa Y Mitsuda K Akagi M 《Chemical communications (Cambridge, England)》2005,(20):2578-2580
The hydrolytic stability of the diastereomeric isomers of ApA was compared and the results show that heterochiral ApAs are more rapidly hydrolyzed than homochiral ApAs at low temperatures, suggesting that hydrolytic selection in cold environments in conjunction with selective polymerization may have been effective in enriching the homochirality of RNA. 相似文献
82.
Batch treatment with Chelex-100 resin was investigated for preconcentration of trace metals in sea water followed by determination by inductively-coupled plasma atomic emission spectrometry. The preconcentration conditions such as resin weight, stirring time, and amount of ammonium acetate buffer solution were carefully examined for effective multi-element preconcentration from sea water. The resin weight could be decreased to 0.5 g (dry weight) for 1 l of sea water, which was much less than that required in the column method, and a preconcentration factor of 100 was achieved. Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Mo, Cd and Pb in sea water were measured with good precision. The detection limits ranged from 6 to 180 ng l?1. The time required for one sample by the batch method was only 3 h. 相似文献
83.
The fluorimetric determination of hydrogen peroxide by using the fluorescence reaction between N-(4'-hydroxyphenyl)-N-(4-methylquinolinyl)amine (HPMQ), cobalt(II) and hydrogen peroxide in the presence of trimethylstearylammonium chloride (STAC) as a cationic surfactant was proposed. The calibration graph was linear in the range 0-2500 ng of hydrogen peroxide per 10 ml of solution at an emission wavelength of 522 nm with excitation at 410 nm. The recovery tests in foods were good. 相似文献
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87.
Shiro Kubuki Kenji Akagi Hiroshi Sakka Zoltán Homonnay Katalin Sinkó Ern? Kuzmann Hiroshi Kurimoto Tetsuaki Nishida 《Hyperfine Interactions》2009,192(1-3):31-36
A relationship between the water purifying effect and structure of 0.5xNa2O·0.5xCaO·5Fe2O3·(95–x)SiO2 glass (Na2O/CaO = 1; NCFS glass) with ‘x’ of 20 and 50 were investigated by means of 57Fe-Mössbauer spectroscopy, X-ray diffraction (XRD), induced coupled plasma optical emission spectroscopy (ICP-OES), as well as absorption spectroscopy, pH and oxidation-reduction potential (ORP) measurements. In the case NCFS glass with ‘x’ of 20, dissolved amounts of total Fe, Na?+?, and Ca2?+? were respectively estimated to be 13.6, 39.1 and 36.7 mg/l, after 10 day-leaching test. On the other hand, the dissolved amounts of total Fe, Na?+? and Ca2?+? were determined to be 34.3, 647.6 and 667.6 mg/l, respectively when ‘x’ was 50. The original pH value of 6.0 was increased to 10.0 and 11.6 after leaching test of NCFS glasses with ‘x’ of 20 and 50, respectively. At the same time, the ORP value was decreased from 30.0 to ?195.8 and ?284.7 mV in the glasses with ‘x’ of 20 and 50, respectively. 相似文献
88.
Hideki Shirakawa Kazuo Akagi Shintaro Katayama Kotaro Araya Akio Mukoh Toshikazu Narahara 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5-7):643-654
Highly aligned polyacetylene films are synthesized by three different methods in which nematic liquid crystals are used as an ordered matrix solvent: Method 1, polymerization of acetylene is carried out in a quiescent nematic solution in which a Ti(OBu)4-AlEt3 Ziegler-Natta catalyst is dissolved homogeneously; Method 2, macroscopic alignment is attained by gravity flow of the nematic liquid crystal-catalyst system; and Method 3, the nematic liquid crystal-catalyst solution is aligned under a magnetic field. Characterization of these films is carried out through SEM observation and measurements of polarized visible and infrared absorption spectra. Results indicate that as-prepared films have highly aligned fibrils. Upon doping by I2 and AsF5, these films exhibit high electrical condactivity of the order of 104 S/cm. 相似文献
89.
Takehiko Terao Shiro Maeda Tokio Yamabe Kazuo Akagi Hideki Shirakawa 《Chemical physics letters》1984,103(5):347-351
13C NMR spectra of undoped polyacetylene,(CH)x, have been measured. The existence of 3.4 mol% methylene moieties as defects in the (CH)x chains has been observed in trans-(CH)x. Measurements of partially cis-to-trans isomerized (CH)x suggest the existence of isolated cis regions. 相似文献