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11.
The high frequency oscillator provides an excellent means of detecting the end-points of titrations performed with ethylenediaminetetraacetic acid or its salts. The determination of various divalent metals is reported, based on both direct and indirect titrations. Because of the great sensitivity of the method it is possible to determine cobalt, nickel, copper (II), zinc, cadmium, lead and manganese (II) in concentration ranges of 1/1000 to 1/6000M. 相似文献
12.
Mitsuo Ishikawa Takamasa Fuchikami Makoto Kumada 《Journal of organometallic chemistry》1978,162(2):223-238
Photolysis of phenylpentamethyldisilane, 1,1-diphenyltetramethyldisilane and 1-isopropyl-1-phenyltetramethyldisilane in the presence of a wide variety of olefins has been studied. All reactions investigated, with the exception of those with 1-methylcyclohexene and tetramethylethylene, afforded the corresponding 1/1 addition products. Yields of the adducts depended highly on the structure of the olefins used. In the photolysis of phenylpentamethyldisilane in the presence of an equimolar mixture of 1,1- and 1,2-bis(trimethylsilyl)ethene under competitive reaction conditions, the main product was the one arising from the 1,1-isomer. A possible mechanism for the process of addition of olefin to the photochemically generated silicon-carbon double-bonded intermediate (A) is discussed. 相似文献
13.
Makoto Kumada Koji Sumitani Yoshihisa Kiso Kohei Tamao 《Journal of organometallic chemistry》1973,50(1):319-326
The hydrosilylation of olefins catalyzed by nickel(II) chloride complexed with 1,2-bis(dimethylphosphino)-1,2-dicarba-closo-dodecaborane produces terminal and internal adducts in comparable amounts. This unusual feature of the reaction is explained in terms of the electron-accepting nature of the carboranyl group. 相似文献
14.
Toshikazu Kurosaki Osamu Takahashi Makoto Okawara 《Journal of polymer science. Part A, Polymer chemistry》1974,12(7):1407-1420
Polymers having stable pendant . radicals were synthesized through their precursor polymers by oxidizing them in air or by H2O2–Na2WO4. Hydrochlorides and sulfates of 4-methacryloylamino- and 4-methacryloyloxy-1-hydroxy-2,2,6,6-tetramethylpiperidines were synthesized as precursor monomers and polymerized by using α,α′-azobisisobutyronitrile under appropriate conditions to precursor polymers of high molecular weight: poly-4-methacryloylamino-/oxy-1-hydroxy-2,2,6,6-tetramethylpiperidinehydrochlorides and sulfates. The precursor polymers were converted to polymers having nitroxyl stable radicals, i.e., poly-4-methacryloylamino-/oxy-2,2,6,6-tetramethylpiperidine-1-oxyls, by oxidation in air or with H2O2–Na2WO4 without any main-chain scission. The structure of the resultant stable radical polymers was determined by infrared, ultraviolet, and ESR spectroscopy. Based on the results of spectroscopic analysis and Kjeldahl analysis, the transformation from precursors to nitroxyl stable radical polymers was found to be quantitative. Investigations on the applicability of polymeric nitroxyl radicals to oxidation-reduction reactions were attempted by means of polarography; the reduction half-wave potential was found to be ?1.16 V for the mercury pool. 相似文献
15.
The polymerization of isobutyl vinyl ether was studied in a heterogeneous system using iron (II) sulfate calcined in air at various temperatures as a catalyst. The maximum activity was shown by the catalyst calcined at 700°C, which effected the polymerization at room temperature in a few seconds, while the sulfate treated at 750°C was totally inactive. Poly(vinyl ethyl ether) was also obtained by the FeSO4 (700°C) catalyst at room temperature. This catalyst formed the crystalline polymer (melting temperature 135–138°C) when the reaction was performed in toluene as solvent at room temperature. Poisoning experiments with Hammett indicators were carried out with the FeSO4 (700°C) catalyst. The treatment with n-butylamine rendered it inactive in the reaction of isobutyl vinyl ether, while its catalytic activity was little affected by dicinnamalacetone. On the basis of the observed results, the nature of active sites of catalyst is discussed. 相似文献
16.
Post-biotinylation of the alkyl azide derivative of trifluoromethyl phenyldiazirine (TPD) was elucidated to apply a photoaffinity biotinylation technique. A photo-modified polyvinilidene difluoride (PVDF) membrane was used as a photolabeled component and we introduced biotin by Staudinger-Bertozzi ligation. The 15 pmol amount of biotinylated reagent was still effective for the visualization of cross-linked product on the matrix. The results show the potential utility of alkyl azide carrying TPD derivatives in the application of photoaffinity biotinylation, which could be useful for the ligands with tight structural requirements. 相似文献
17.
18.
Numerical Algorithms - In this paper, we propose an infeasible arc-search interior-point algorithm for solving nonlinear programming problems. Most algorithms based on interior-point methods are... 相似文献
19.
Tadayuki Hara Jitsuro Sugie 《NoDEA : Nonlinear Differential Equations and Applications》1995,2(4):527-551
In this paper we study the problem whether all trajectories of the system
=y–F(x) and
=–g(x) cross the vertical isocline which is very important for the existence of periodic solutions and oscillation theory. The problem has not been solved for the critical case:
相似文献
20.
A novel electron spin echo method employing detection of FID and transient echo shape following selective hole burning in the EPR spectrum has been applied to study γ-irradiated malonic acid. The dipolar lineshapes of stabilized free radicals are separated into bulk and pairwise contributions; both of them have proved to be Lorentzian. 相似文献
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