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261.
Kiyoshi Koyama Masato Nishimura Isao Hashida 《Journal of polymer science. Part A, Polymer chemistry》1971,9(9):2439-2449
The polymerization of methyl methacrylate initiated with a peracid-type resin was studied. The peracid-type resin was prepared by the oxidation of cation-exchange resin (Amberlite IRC-50) with 60 wt-% aqueous hydrogen peroxide in the presence of p-toluenesulfonic acid. It was found that the peracid-type resin was effective as an initiator for polymerization of methyl methacrylate. The kinetic investigation indicated that this polymerization proceeded by a radical mechanism, and the overall activation energy of polymerization was 15.8 kcal/mole. No effect of macromolecular catalyst on steric structure of the resulting polymer was observed. Some graft polymer was formed in bulk polymerization. On the other hand, only a homopolymer was obtained in solution polymerization. From the results obtained, a possible mechanism of initiation with the peracid-type resin is proposed and discussed. 相似文献
262.
Palladium-catalyzed oxidative alkynylation of alkenes using tert-propargylic alcohols as alkynylation reagents via C-C bond cleavage under an oxygen atmosphere affords the corresponding ene-yne compounds. 相似文献
263.
Hiroyoshi Kanai Tatsuya Yoshikawa Tadahide Sone Yasuo Nishimura 《Reaction Kinetics and Catalysis Letters》2002,75(2):213-224
Highly dispersed V2O5/SiO2(CVD catalyst) was prepared by the reaction of vaporized VO(OPri)3 with silica at 293 K, whose process was followed by an IR technique. The rate of propylene photooxidation increased with an increase in V2O5 loading for CVD catalysts, but leveled off for impregnated ones. The CVD catalysts were characterized by XAFS and photoluminescence spectroscopy. 相似文献
264.
M Yasuoka Y Nishimura T Nagaoka K Watari 《Journal of Thermal Analysis and Calorimetry》2006,83(2):407-410
The ceramic industry uses enormous amounts of energy
to produce products at high temperatures. Energy-saving measures based on
sintering process improvements are examined.
Oxide ceramics were irradiated by two different methods
during microwave sintering: intermittent use of the same high power levels
(time-control method) and continuous use of lower, increasing levels of power
(power-control method). We found that: 1) the power consumption and efficiency
of the time-control method were lower than those of the power-control method;
2) the power-control method gave more precise control of temperature under
our experimental conditions; 3) sample densification did not differ greatly
between the two methods; and 4) grain growth did not differ greatly between
the two methods. 相似文献
265.
Asymmetric epoxidation reaction of α,β-unsaturated carbonyl compounds with alkylperoxide was catalyzed by an external chiral tridentate aminodiether-lithium peroxide giving epoxides with good enantiomeric excess. Slow addition of alkylhydroperoxide was beneficial for a catalytic asymmetric reaction. Lone pair electron-differentiating coordination of a carbonyl oxygen to lithium is another critical factor for high enantioselectivity. 相似文献
266.
Hirokazu Nishimura 《International Journal of Theoretical Physics》1993,32(3):443-488
It is well known that the real and complex numbers in the Scott-Solovay universeV
(B) of ZFC based on a complete Boolean algebraB are represented by the real-valued and complex-valued Borel functions on the Stonean space ofB. The main purpose of this paper is to show that the separable complex Hilbert spaces and the von Neumann algebras acting on them inV
(B) can be represented by reasonable classes of families of complex Hilbert spaces and of von Neumann algebras over. This could be regarded as the duality between Boolean-valued analysis developed by Ozawa, Takeuti, and others and the traditional reduction theory based not on measure spaces but on Stonean spaces. With due regard to Ozawa, this duality could pass for a sort of reduction theory forAW
*-modules over commutativeAW
*-algebras and embeddableAW
*-algebras. Under the duality we establish several fundamental correspondence theorems, including the type correspondence theorems of factors. 相似文献
267.
268.
A. Ishii T. Itoh Y. Kodera A. Matsushima M. Hiroto H. Nishimura Y. Inada 《Research on Chemical Intermediates》1997,23(8):683-689
Chlorophyll a was adsorbed onto freeze-dried bentonite to form chlorophyll-bentonite conjugate, which was photostable against light illumination [1]. Physiological function of chlorophyll-bentonite conjugate is explored; increasing the amount of chlorophyll adsorbed onto bentonite leads to enhancement of the photostability accompanied with shifting the absorbance maximum to longer wavelength. Furthermore, the conjugate exhibits a high photoreduction ability of nitro blue tetrazolium, NBT, through the formation of superoxide anion without any loss of photosensitive activity even after 50 hr illumination. 相似文献
269.
270.