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排序方式: 共有166条查询结果,搜索用时 31 毫秒
1.
It is theoretically predicted that the Nernst coefficient is strongly suppressed and the thermal conductance is quantized in the quantum Hall regime of the two-dimensional electron gas. The Nernst effect is the induction of a thermomagnetic electromotive force in the y-direction under a temperature bias in the x-direction and a magnetic field in the z-direction. The quantum nature of the Nernst effect is analyzed with the use of a circulating edge current and is demonstrated numerically. The present system is a physical realization of the non-equilibrium steady state. 相似文献
2.
Okihiro Sugihara Tomoyuki Hirama Hisashi Fujimura Naomichi Okamoto 《Optical Review》1996,3(3):150-152
Thin film waveguides of germanosilicate glass are fabricated byrf-sputtering. Second-order nonlinearity ofd 33=3.2 pm/V is obtained from electrically poled film, and the lifetime of the nonlinearity is found to be310 years. The poled channel-waveguide is prepared and the Cerenkov-type phase-matched frequency doubling is successfully observed. 相似文献
3.
The effect of added substances was studied on the yield of glutamic acid produced by gamma-ray irradiation of 2-oxoglutaric acid and ammonia in aqueous solution. The contents of amino acids in the irradiated solutions were determined with amino acids analyzer. Sodium nitrate, allyl alcohol or sodium formate was used as an added substance. The yield of glutamic acid significantly decreased by the addition of nitrate, and it was little affected by the addition of allyl alcohol. In the presence of formate the yield increased from G = 0.4 (2-oxoglutaric acid 0.05M and ammonium hydroxide 2M) to G = 1.1. As a result, it was found that hydrated electron contributes on the formation of glutamic acid, but hydroxyl radical does not. The yield showed a maximum at ca. 0.1 M ammonium hydroxide concentration. These facts indicate that NH2 radical does not contribute to the formation of glutamic acid. As a reaction mechanism, it can be explained that 2-oxoglutaric acid which had been reduced by hydrated electron reacts with ammonia. 相似文献
4.
Akita M Miyaji T Muroga N Mock-Knoblauch C Adam W Hikichi S Moro-oka Y 《Inorganic chemistry》2000,39(10):2096-2102
Mono- and dinuclear hydroxopalladium complexes (kappa 2-TpiPr2,X)(py)Pd-OH (1; X = H, Br) and (mu-OH)2[Pd(kappa 2-TpiPr2)(H2O)]2 (2) are prepared by base hydrolysis of the corresponding chloride complexes (kappa 2-TpiPr2,X)(py)Pd-Cl (3) and (mu-Cl)2[Pd(kappa 3-TpiPr2)]2 (4), respectively. Functionalization of the OH part in 1 is effected via dehydrative condensation with protic substrates (H-A) to give a series of substituted products, (kappa 2-TpiPr)(py)Pd-A (5), and treatment of the dinuclear complex 2 with excess acetic acid affords the mononuclear diacetato complex 6, (kappa 2-TpiPr2-H)Pd(OAc)2(HOAc). Complexes 1-4 and 6 have been characterized crystallographically, and it is revealed that complexes 2 and 6 involve cyclic hydrogen-bonding interaction among the nitrogen atom of the pendent noncoordinated pyrazolyl group, the hydrogen atom in the protic part of the ligand (OH, AcOH), and, in the case of 2, an external water molecule. 相似文献
5.
Uehara K Hikichi S Inagaki A Akita M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(9):2788-2809
A series of dinuclear complexes, [Tp(R)M--M'L(n)] [Tp(iPr(2) )M--Co(CO)(4) (1; M=Ni, Co, Fe, Mn); Tp(#)M--Co(CO)(4) (1'; M=Ni, Co); Tp(#)Ni--RuCp(CO)(2) (3')] (Tp(iPr(2) )=hydrotris(3,5-diisopropylpyrazolyl)borato; Tp(#) (Tp(Me(2),4-Br))=hydrotris(3,5-dimethyl-4-bromopyrazolyl)borato), has been prepared by treatment of the cationic complexes [Tp(iPr(2) )M(NCMe)(3)]PF(6) or the halo complexes [Tp(#)M--X] with the appropriate metalates. Spectroscopic and crystallographic characterization of 1-3' reveals that the tetrahedral, high-spin Tp(R)M fragment and the coordinatively saturated carbonyl-metal fragment (M'L(n)) are connected only by a metal-metal interaction and, thus, the dinuclear complexes belong to a unique class of xenophilic complexes. The metal-metal interaction in the xenophilic complexes is polarized, as revealed by their nu(CO) vibrations and structural features, which fall between those of reference complexes: covalently bonded species [R--M'L(n)] and ionic species [M'L(n)](-). Unrestricted DFT calculations for the model complexes [Tp(H(2) )Ni--Co(CO)(4)], [Tp(H(2) )Ni--Co(CO)(3)(PH(3))], and [Tp(H(2) )Ni--RuCp(CO)(2)] prove that the two metal centers are held together not by covalent interactions, but by electrostatic attractions. In other words, the obtained xenophilic complexes can be regarded as carbonylmetalates, in which the cationic counterpart interacts with the metal center rather than the oxygen atom of the carbonyl ligand. The xenophilic complexes show divergent reactivity dependent on the properties of donor molecules. Hard (N and O donors) and soft donors (P and C donors) attack the Tp(R)M part and the ML(n) moiety, respectively. The selectivity has been interpreted in terms of the hard-soft theory, and the reactions of the high-spin species 1-3' with singlet donor molecules should involve a spin-crossover process. 相似文献
6.
7.
Naomichi Furukawa Mitsuo Fukumura Takehiko Nishio Shigeru Oae 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):231-237
Abstract Various N-acyldiphenylsulfilimines (1a-k) were found to undergo photolysis in argon atmosphere, to afford the corresponding isocyanates, diphenyl sulfide and diphenyl disulfide. Attempts to trap intramolecularly the acylnitrene with olefinic linkage or sulfide afforded small amounts of the trapped products, whereas photolysis of N-mesitoyldiphenyl-sulfilimine (Ia) afforded a C–H inserted product of the nitrene in a substantial yield together with the isocyanate. Benzophenone-sensitized photolysis of Ia indicates that the nitrene generated is a singlet species. 相似文献
8.
Akio Urushima Dr. Daisuke Taura Makoto Tanaka Naomichi Horimoto Dr. Junki Tanabe Dr. Naoki Ousaka Prof. Tadashi Mori Prof. Eiji Yashima 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(19):7548-7556
A novel 2,6-anthrylene-linked bis(m-terphenylcarboxylic acid) strand ( 1 ) self-associates into a racemic double-helix. In the presence of chiral mono- and diamines, either a right- or left-handed double-helix was predominantly induced by chiral amines sandwiched between the carboxylic acid strands with accompanying stacking of the two prochiral anthracene linker units in an enantiotopic face-selective way, as revealed by circular dichroism and NMR spectral analyses. The photoirradiation of the optically active double helices complexed with chiral amines proceeded in a diastereo- (anti or syn) and enantiodifferentiating way to afford the chiral anti-photodimer with up to 98 % enantiomeric excess when (R)-phenylethylamine was used as a chiral double-helix inducer. The resulting optically active anti-photodimer can recognize the chirality of amines and diastereoselectively complex with chiral amines. 相似文献
9.
Akio Urushima Daisuke Taura Makoto Tanaka Naomichi Horimoto Junki Tanabe Naoki Ousaka Tadashi Mori Eiji Yashima 《Angewandte Chemie (International ed. in English)》2020,59(19):7478-7486
A novel 2,6‐anthrylene‐linked bis(m‐terphenylcarboxylic acid) strand ( 1 ) self‐associates into a racemic double‐helix. In the presence of chiral mono‐ and diamines, either a right‐ or left‐handed double‐helix was predominantly induced by chiral amines sandwiched between the carboxylic acid strands with accompanying stacking of the two prochiral anthracene linker units in an enantiotopic face‐selective way, as revealed by circular dichroism and NMR spectral analyses. The photoirradiation of the optically active double helices complexed with chiral amines proceeded in a diastereo‐ (anti or syn) and enantiodifferentiating way to afford the chiral anti‐photodimer with up to 98 % enantiomeric excess when (R)‐phenylethylamine was used as a chiral double‐helix inducer. The resulting optically active anti‐photodimer can recognize the chirality of amines and diastereoselectively complex with chiral amines. 相似文献