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171.
The copper NMR in a two-dimensional Heisenberg antiferromagnet Cu(HCOO)2 ·4H2O (TN = 17 K) was observed using a standard spin- echo method at liquid He temperatures. The field-dependence of the 63Cu NMR frequency was measured for H0 (? 56 kOe) | b-axis. The result was interpreted by taking into account a zero-point spin reduction of about 35% in addition to the rotation of the antiferromagnetic spin axis. The amount of the observed spin reduction is in good agreement with the prediction of spin-wave theory. 相似文献
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Junichi Goto Nobhuharu Goto Atsuko Hikichi Tomoko Nishimaki Toshio Nambara 《Analytica chimica acta》1980
Two highly sensitive, chiral derivatization reagents, D- and L-1-aminoethyl-4-dimethyl-aminonaphthalene, were synthesized from 1-dimethylaminonaphthalene. Condensation of carboxylic acids with the chiral reagent was readily effected in the presence of a watersoluble carbodiimide. The diastereoisomeric amides formed from N-acetylamino acid and α-arylpropionic acid enantiomers were efficiently resolved by normal phase chromatography (μPorasil column) -with hexane/ethyl acetate or hexane/tetrahydrofuran as a mobile phase. With a fluorescence detector (excitation 320 nm, emission 395 nm), the detection limit was 0.1 ng. 相似文献
175.
Various types of α-cyanoallylic acetates were undergone the palladium-catalyzed rearrangement to give the γ-acetoxy-α,β-unsaturated nitriles in high yields. These rearranged acetates were conveniently transformed into the furan derivatives often encountered in natural products by the reduction using diisobutylaluminum hydride. 相似文献
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Bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt(III) is proposed for the extraction and spectrophotometric determination of sulphated and sulphonated surfactants. The complex and the surfactants form ion-pairs which are extracted into benzene from O.1M hydrochloric acid. The absorbance of the benzene phase is measured at 560 nm against a reagent blank. Less than 25 mug of sodium di-(2-ethylhexyl) sulphosuccinate in 50-200 ml of sample solution is determined reproducibly by the proposed method. When applied to river water samples, the proposed method gives results which agree very well with those obtained by the standard Methylene Blue method. However, the proposed method is simpler and more sensitive than the Methylene Blue method. 相似文献
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Eijiro Kamata Ryozo Nakashima Kazuo Goto Masamichi Furukawa Shozo Shibata 《Analytica chimica acta》1982
After removal of lipid and acid digestion of bone samples, cadmium is separated from the matrix by two extractions with dithizone in carbon tetrachloride. The first extraction at pH 3–3.5 removes cadmium from the matrix; the second extraction, at pH 8.5 in the presence of 2-hydroxyethylethylenediaminetriacetic acid, is needed to prevent suppression of the cadmium signal by zinc. Cadmium is finally measured in the back-extract into 0.24 M hydrochloric acid. Less than 10 ng g-1 cadmium in fresh bone can be determined within a relative standard deviation of 10%. 相似文献