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111.
Syntheses of 3-substituted indazoles and benzoisoxazoles were efficiently accomplished with the aid of Pd-catalyzed intramolecular carbon-nitrogen and carbon-oxygen bond formations. The catalyst system described herein allows the cyclization to proceed under very mild conditions and thus could be applied to a wide range of substrates with acid- or base-sensitive functional groups. A total synthesis for the indazole ring-containing natural product nigellicine is also described. 相似文献
112.
Ki Chul Park Masatsugu Fujishige Susumu Arai Morinobu Endo 《Journal of Physics and Chemistry of Solids》2008,69(10):2481-2486
High-speed agitation by a mixing blade has efficiently achieved the cutting of a large diameter (100-150 nm) of multi-walled carbon nanotubes. The cutting process is caused by an inter-collision of the nanotubes with high transfer energy. The collision-induced cutting allows for the shortening of the nanotubes without serious damage of the original graphitic layers due to the cutting effect being limited to the collision points. Furthermore, the operation under ambient atmosphere introduces oxygen-containing functional groups to the cut nanotubes. The estimated length distribution has indicated that high-speed agitation achieves a large cutting effect during a short duration of several minutes. 相似文献
113.
Large-scale silicon isotope separation based on the IRMPD of natural Si2F6 has been carried out using a commercially available high power CO2 TEA laser and a flow reaction system. The decomposition product SiF4 containing 19–33% of 30Si was obtained at a production rate of 1.5×10–2–2.6×10–2 mol·h–1, depending on experimental parameters such as laser wavelength, laser fluence, pressure, and flow rate. SiF4 containing 12% of 29Si was obtained under slightly different conditions, i.e., at a shorter wavelength than that for 30Si. When 39% of Si2F6 was decomposed at a slow flow rate, residual Si2F6 was found to have 99.7% of 28Si. The production rate was 4.2×10–2 mol·h–1. 相似文献
114.
115.
Asao Arai 《Journal of Geometry and Physics》1993,11(1-4):465-490
Infinite dimensional analysis is developed on an abstract Boson-Fermion Fock space. A general class of Dirac operators acting there is introduced and properties of them are investigated. An index theorem for the Dirac operators is established in terms of a path integral on a loop space. It is shown that the abstract formalism presented here gives a mathematical unification for some models of supersymmetric quantum field theory. 相似文献
116.
S. Arai M. Kawai H. Morimoto K. Tanaka H. Seyama M. Soma 《Applied physics. B, Lasers and optics》1988,47(3):243-245
The IRMPD of Si2F6 by a CO2 TEA laser was applied to isotopically selective CVD of silicon. A white film, probably consisting of polymers of SiF2, was deposited on a metal foil during the irradiation of natural Si2F6 with the laser radiation at 951.19 cm–1 and about 1.5 J cm–2. Upon heating, the film became dark brown, evolving SiF4. The30Si content was found to be as high as about 20%. 相似文献
117.
Junji Furukawa Yoshihiro Arai Eiichi Kobayashi 《Journal of polymer science. Part A, Polymer chemistry》1976,14(9):2243-2250
A kinetic investigation of the alternating copolymerization of butadiene and methyl methacrylate with the use of a system of ethylaluminum dichloride and vanadyl chloride as a catalyst was undertaken. The relation between the polymer yield and the molar fraction of methyl methacrylate in the feed was examined by continuous variation of butadiene and methyl methacrylate, the concentrations of total monomer, ethylaluminum dichloride, and vanadyl chloride being kept constant. This continuous variation method revealed that the polymer yield attains its maximum value with a monomer feed containing less than the 0.5 molar fraction of methyl methacrylate. This value of the molar fraction of methyl methacrylate affording the maximum polymer yield decreased on increasing the total monomer concentration but was not changed on varying the concentration of ethylaluminum dichloride. The number of active species estimated from the relation between yield and molecular weight of the polymer was almost constant, regardless of the molar fraction of methyl methacrylate in the feed. Consequently, it can be said that the maximum polymer yield depends mainly on the propagation reaction, not on the initiation reaction or the termination reaction. Three types of the mechanism have been discussed for this alternating copolymerization: polymerization via alternating addition of butadiene and methyl methacrylate complexed with ethylaluminum dichloride by the Lewis-Mayo scheme; polymerization via the ternary intermediate of butadiene, methyl methacrylate, and ethylaluminum dichloride; polymerization via the complex formation of butadiene and methyl methacrylate complexed with ethylaluminum dichloride occurring only at the growing polymer radical. From the kinetic results obtained, it was shown that the first and third schemes are excluded, and polymerization by way of the ternary intermediate is compatible with the data. 相似文献
118.
Ribbon-form Sendust was prepared by a roll quenching method. The size of the ribbon was 20∼110 μm thick, 2∼8 mm wide and 5∼10
m long. The normal direction of the ribbon plane was parallel to the [100] as well as the [110] axes, and no preferential
directions exist within the ribbon plane. Vickers hardnessH
v
of the as-prepared ribbon was 563±7, decreased with increasing the annealing time and became almost constant. The minimum
bending diameter of the as-prepared ribbon was 8 mm and increased gradually with increase of the annealing time. Initial permeability
of the 84.80 Fe·9.50 Si·5.70 Al ribbon was about 34,000 in the frequency range from 1 to 3kHz and decreased to be 10,000 at
85 kHz. The permeability of the molded core in a resin was about 21,000 in the frequency range from 1 to 3 kHz. 相似文献
119.
The properness of the efficient solution of the optimal problem with multicriteria has been independently defined by Kuhn and Tucker, Geoffrion, and Klinger. A theorem of Geoffrion describes the relation between Geoffrion's and Kuhn and Tucker's properness. In this paper, the dual part of the theorem is given, and some geometric approach is applied to derive the optimal conditions of proper efficient solutions and improper efficient solutions. 相似文献
120.
Changes in Si(111) 7 × 7 pattern with air exposure are studied by RHEED. The relation between exposure time and air-oxidized film thickness is obtained using an ellipsometer. As a result, it is found that the 7 × 7 surface after air exposure (760 Torr, 20 h) still exhibits several 7 × 7 spots near normal ones in the RHEED pattern. The air-oxidized film thickness corresponding to this exposure is about 13 Å. The fact that the 7 × 7 spots do not disappear with HF etching of the oxide film indicates that the superstructure remains not at the oxide surface but at the substrate selvedge. The 7 × 7 spots gradually disappear after longer exposure time and no 7 × 7 spots can be observed after 40 h (about 15 Å in oxide thickness). For a sample exposed longer than 40 h, no 7 × 7 spots reappear, even if the oxide is removed by HF. Therefore, it is concluded that the structure of the substrate selvedge changes with exposure time. 相似文献