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71.
Yoshiaki Hidaka Takuji Nakamura Aya Miyauchi Toshihiko Shiraishi Hiroyuki Kawano 《国际化学动力学杂志》1989,21(8):643-666
Propyne (p-C3H4) or allene (a-C3H4) mixtures, highly diluted with Ar, were heated to the temperature range 1200–1570 K at pressures of 1.7–2.6 atm behind reflected shock waves. The thermal decompositions of propyne and allene were studied by both measuring the profiles of the IR emission at 3.48 μm or 5.18 μm and analyzing the concentrations of reacted gas mixtures. The mechanism and the rate constant expressions were discussed from both the profiles and the concentrations of reactant and products obtained. The rate constant expressions for reactions, (1) p-C3H4 → a-C3H4, (?1) a-C3H4 → p-C3H4, and (5) p-C3H4 + H → CH3 + C2H2 were evaluated. 相似文献
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74.
A newly FDA-approved heart failure therapy (LCZ696, supramolecular complex of sacubitril (SAC) and valsartan (VAL), Entresto?) is analyzed with a stability indicating HPLC–DAD method. For the newly introduced drug, SAC, there is no sufficient information about its stability under various stress conditions. The proposed chromatographic method was applied to the kinetic investigation of the acidic, alkaline, and oxidative degradation of SAC with the estimation of its activation energy and half-life at room temperature by the aid of Arrhenius plots. Kinetic investigation was conducted using either different strengths of HCl, NaOH, and H2O2 at one selected temperature or different temperature degrees at one selected reagent strength, for the acidic, alkaline, and oxidative stress conditions. It was found that the pseudo-first-order kinetics was followed at each case. The half-lives at room temperature using 0.1?M HCl, 0.01?M NaOH, and 15% H2O2 were found to be 20.50, 2.76, and 51.58?hr. The chromatographic method was achieved using Zorbax Eclipse plus-C18 (4.6?×?250?mm, 5?µm) with isocratic elution of mobile phase composed of acetonitrile and 0.025?M phosphate buffer (pH3) in a ratio of 60:40 (v/v). 相似文献
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[reaction: see text] A synthesis of a C4-epi-C1-C6 fragment of the antitumor agent FR901464 is reported. The advanced intermediate prepared in this study contains two of the three correct stereocenters found in the C1-C6 moiety of FR901464. For the preparation of this intermediate, we have developed a highly diastereoselective bromolactolization of a delta-alkenyl ketone. 相似文献
77.
Radiocesium concentrations in cow's milk from two producing districts in Japan were measured monthly for three years following the Chernobyl accident. The Chernobyl contribution in137Cs concentration was evaluated from the134Cs concentration and the137Cs/134Cs ratio. The highest137Cs concentration of 0.6 Bq l–1 was observed in May 1986 and the Chernobyl contribution has decreased during three years to levels corresponding to the contribution from past nuclear weapons fallout. Annual values of child internal dose through milk consumption were estimated at 0.6, 0.3 and 0.1 Sv for the first, the second and the third year following the accident, respectively. 相似文献
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79.
Kunihiko Yokoi Toyomi Tomisaki Tsutomu Koide Constant M. G. Berg 《Fresenius' Journal of Analytical Chemistry》1995,352(6):547-549
The effectivity of UV irradiation with low and high pressure mercury (L-Hg and H-Hg) lamps on the decomposition of organic compounds in aqueous solutions, as pretreatment for the voltammetric determination of trace metals, is compared. The photolytic decomposition with the L-Hg lamp was much faster than with the H-Hg lamp. The higher efficiency of the L-Hg lamp is caused by its greater light intensity at short wavelengths. Interferences of organic compounds on the voltammetric determination of nickel and indium were eliminated successfully by 90 min irradiation with the L-Hg lamp. Humic acid and organic interference with the voltammetric determination of nickel in natural river water were successfully eliminated. The decomposition using the L-Hg lamp can be carried out without added oxidizing reagents and at room temperature, thus eliminating loss of water samples by evaporation at higher temperature. 相似文献
80.
Yasuo Koma Naoyuki Koide Akira Tanaka Kazuyoshi Iimura Masatami Takeda 《Journal of polymer science. Part A, Polymer chemistry》1979,17(2):465-471
The complex of acrylonitrile (AN) with trimethylaluminum (AlMe3) was successfully isolated as a white needlelike crystal with a melting point of 42.5°C. In this article the preparation of the complex is described in detail. Cryoscopic and spectral investigations indicated that the complex is formed by an equimolar ratio of AN and AlMe3. From the measurement of the x-ray diffraction photograph of the crystal the repeat period was determined to be 9.47 ± 0.05 Å. 相似文献