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21.
[reaction: see text] A new method for the synthesis of thiocarbamates has been developed. When dialkyl or diaryl disulfides were allowed to react with secondary amines and carbon monoxide in the presence of a catalytic amount of a palladium complex, the thiocarbamates were obtained in moderate to good yields. In contrast to that of secondary amines, in the reaction of a primary amine, no formation of thiocarbamate was confirmed, but urea was formed in good yield. 相似文献
22.
Kazuhiro Watanabe Noboru Akino Tetsuo Aoyagi Noboru Ebisawa Yukio Fujiwara Atsusi Honda Takashi Inoue Takao Itoh Mikito Kawai Minoru Kazawa Junichi Koizumi Masaaki Kuriyama Kenji Miyamoto Naoki Miyamoto Kazuhiko Mogaki Yoshihiro Ohara Tokumichi Ohga Yoshikazu Okumura Hiroshi Oohara Katsumi Ohshima Fujio Satoh Kazuhiko Shimizu Syunji Takahashi Hirotsugu Usami Katsutomi Usui Masahiro Yamamoto Takeshi Yamazaki 《Radiation Physics and Chemistry》1997,49(6):631-639
A negative-ion-based neutral beam injector (N-NBI) has been constructed for JT-60U. The N-NBI is designed to inject 500 keV, 10 MW neutral beams using two ion sources, each producing a 500 keV, 22 A D− ion beam. In the preliminary experiment using one ion source, a D− ion beam of 13.5 A has been successfully accelerated with an energy of 400 keV (5.4 MW) for 0.12 s at an operating pressure of 0.22 Pa. This is the highest D− beam current and power in the world. Co-extracted electron current was effectively suppressed to the ratio of Ie/ID− < 1. The highest energy beam of 460 keV, 2.4 A, 0.44 s has also been obtained. To realize 1 MeV class NBI system for ITER (International Thermonuclear Experimental Reactor), demonstration of ampere class negative ion beam acceleration up to 1 MeV is an important mile stone. To achieve the mile stone, a prototype accelerator and a 1 MV, 1 A test facility called MeV Test Facility (MTF) were constructed. Up to now, an H− ion beam was accelerated up to the energy of 805 keV with an acceleration drain current of 150 mA for 1 s in a five stage electrostatic multi-aperture accelerator. 相似文献
23.
A series of new compounds Ln(Fe3+M2+)O4 [Ln : Y, Er, Tm, Yb, and Lu, M : Mg, Mn, Co, Cu, and Zn] were successfully synthesized and their lattice constants were determined. These compounds have the same crystal structure as YbFe2O4 and Fe3+ and M2+ are both surrounded by five oxygen ions forming a trigonal bipyramid. The synthetic conditions are presented. They are strongly dependent upon the constituent cations of the compound. 相似文献
24.
Noboru Matsumura Motoyuki Kusamiya Hiroo Inoue Masanori Yasui Fujiko Iwasaki 《Journal of heterocyclic chemistry》1995,32(4):1269-1275
1,3-Bis(p-substituted-phenylthiocarbamoyl)-2-imidazolidinethiones 3a-f reacted with bromine to give trithiadiazapentalene derivatives 5a-f , bearing the exocyclic C-N double bonds, in moderate yields. The molecular structure of 5b was elucidated by the X-ray crystallographic analysis. The treatment of 5b-f with hydrochloric acid gave the ring-opening products, 1,3-bis(p-substituted-phenylthiocarbamoyl)-2-imidazo-lidinones 9b-f , accompanied by the production of elemental sulfur. Reduction of 5b , 5d , and 5e with sodium borohydride gave the ring-opening compounds, 1,3-bis(p-substituted-phenylthiocarbamoyl)-2-imidazolidines 13b , 13d , and 13e respectively. 相似文献
25.
Spectroscopic and excited-state properties of tri-9-anthrylborane (TAB), showing unique absorption and fluorescence characteristics originating from p(boron)-pi(anthryl group) orbital interactions, were studied in 12 solvents. Although the absorption maximum energy (nu(a)) of TAB which appeared at around 21 x 10(3) cm(-1) (band I) was almost independent of the solvent polarity parameter, f(X) (f(X) = (D(s) - 1)/(2D(s) + 1) - (n(2) - 1)/(2n(2) + 1) where D(s) and n represent the static dielectric constant and the refractive index of a solvent, respectively), the fluorescence maximum energy (nu(f)) showed a linear correlation with f(X). The f(X) dependence of the value of nu(a) - nu(f) demonstrated that the change in the dipole moment of TAB upon light excitation was approximately 8.0 D, indicating that absorption band I was ascribed to an intramolecular charge-transfer transition in nature. The excited electron of TAB was thus concluded to localize primarily on the p orbital of the boron atom. Furthermore, it was shown that the fluorescence lifetime and quantum yield of TAB varied from 11.8 to 1.1 ns and from 0.41 to 0.02, respectively, with an increase in f(X). The present results indicated that the nonradiative decay rate constant (k(nr)) of TAB was influenced significantly by f(X). Excited-state decay of TAB was understood by intramolecular back-electron (charge) transfer from the p orbital of the boron atom to the pi orbital of the anthryl group, which was discussed in terms of the energy gap dependence of k(nr). Specific solvent interactions of TAB revealed by the present spectroscopic and photophysical studies are also discussed. 相似文献
26.
Noboru Nakanishi 《General Relativity and Gravitation》1995,27(1):65-69
The conventional perturbative approach to quantum gravity is based on the expansion in powers of k, wherek denotes the Einstein gravitational constant. The introduction of a square root is due to the unreasonable postulate that thek0 limit of the gravitational field is ac-number. It is more natural that it is aq-number, which can be determined explicitly by the theory, and then the expansion becomes that in powers ofk but not of k. Thus the nonrenormalizability of Einstein gravity should be completely reconsidered in the light of the new expansion. 相似文献
27.
Kiyoharu Tadanaga Kazuki Iwashita Tsutomu Minami Noboru Tohge 《Journal of Sol-Gel Science and Technology》1996,6(1):107-111
Nylon-6 substrates were coated with SiO2 thin films by the sol-gel method and their water permeability coefficient was evaluated. Methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) were used as starting materials. The addition of MTES to TEOS has enabled the formation of crack-free thin films on the substrates. The thin films strongly adhered to the substrates. The water permeability coefficients of nylon-6 substrates coated with these thin films decreased with the increase in the ratio of TEOS to the total alkoxides. The pretreatment of the nylon-6 substrates with -aminopropyltriethoxysilane was found to be effective to suppress the water permeability. The water permeability was suppressed by about 40% under the optimal condition. 相似文献
28.
29.
CT complexes of 1,2,4,5-tetracyanobenzene were formed in the inner part of neutral micelles and in the surface region of ionic ones. The excitation of the CT absorption band of these complexes gives broad and structureless CT fluorescence spectra, their lifetimes being relatively short (≈10 ns). Micellar effect upon ionic photodissociation was observed, and their quantum yeild is smaller than that obtained in acetonitrile. These results are quite different from those on another typical excited CT system of pyrene and N,N-dimethylaniline. 相似文献
30.