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排序方式: 共有171条查询结果,搜索用时 15 毫秒
11.
Toyoki Kunitake 《Macromolecular Symposia》1995,98(1):45-51
Recent progresses in the self assembly of ultrathin polymer films are described. Bilayer membranes of polymeric hydrogen-bond networks are formed in water. Two-dimensional networks of organic and inorganic polymers are formed in cast films of synthetic bilayer membranes to give stable multilayer films upon removal of the matrices. The monolayer at the air-water interface constitutes suitable templates for 2D polymer networks, and it may be either removed or part of the 2D film. Successive adsorption of polycations and polyanions under carefully controlled conditions produces layered polyion complexes in the stepwise manner. Various polymer chains are epitaxially adsorbed onto graphite. All these results indicate that molecularly defined 2D polymer structures are readily available. 相似文献
12.
Feng DL Damascelli A Shen KM Motoyama N Lu DH Eisaki H Shimizu K Shimoyama Ji JI Kishio K Kaneko N Greven M Gu GD Zhou XJ Kim C Ronning F Armitage NP Shen ZX 《Physical review letters》2002,88(10):107001
The low-energy electronic structure of the nearly optimally doped trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta) is investigated by angle-resolved photoemission spectroscopy. The normal state quasiparticle dispersion and Fermi surface and the superconducting d-wave gap and coherence peak are observed and compared with those of single- and bilayer systems. We find that both the superconducting gap magnitude and the relative coherence-peak intensity scale linearly with T(c) for various optimally doped materials. 相似文献
13.
Toyoki Koga 《Foundations of Physics》1974,4(2):261-266
In a previous paper it was shown that the tunnel effect does not occur in the motion of an undeformable wavelet which we obtained by solving the Schrödinger equation and interpreted as representing a single particle. In the present supplementary paper we solve the same Schrödinger equation while modifying one of the restrictive conditions assumed previously, and obtain wavelets which deform in force fields. Tunnel effects are seen in the motion of these deformable wavelets. An apparent inaccuracy pointed out mathematically in these solutions is shown to be insignificant under conditions which are feasible in the physical sense. 相似文献
14.
Cadmium hydroxide nanostrands with a diameter of 1.9 nm were spontaneously formed by raising the pH of a dilute Cd(NO3)2 solution. The length reaches a few micrometers and the aspect ratio exceeds 1000. The crystallographic structure was successfully elucidated by high-resolution electron microscopy. The surface of the nanostrands was remarkably positively charged and adsorbed an astonishing number of negatively charged dye molecules. 相似文献
15.
Gozar A Blumberg G Littlewood PB Dennis BS Motoyama N Eisaki H Uchida S 《Physical review letters》2003,91(8):087401
Raman measurements in the 1.5-20 cm(-1) energy range were performed on single crystals of Sr14-xCaxCu24O41. A quasielastic scattering peak (QEP) which softens with cooling is observed only in the polarization parallel to the ladder direction for samples with x=0, 8, and 12. The QEP is a Raman fingerprint of pinned collective density wave excitations screened by uncondensed carriers in the ladder structures. Our results suggest that transport in metallic samples, which is similar to transport in underdoped high-T(c) cuprates, is driven by a collective electronic response. 相似文献
16.
Hideo Nagashima Yuichi KuboMitsunobu Kawamura Takashi NishikataYukihiro Motoyama 《Tetrahedron》2011,67(40):7667-7672
A triruthenium cluster, (μ3, η2, η3, η5-acenaphthylene)Ru3(CO)7 effectively catalyzes primary-alkylation reaction of electron-rich aromatic rings using a combination of hydrosilane and ester as a source of the primary-alkyl group. The reaction involves electrophilic substitution of arenes by carbocationic species stabilized by a neighboring alkoxy or siloxy group generated during the reduction of esters giving alkylated arenes after reductive removal of the alkoxy or siloxy group at the benzylic position. 相似文献
17.
Motoyama Y Sakakura T Takemoto T Shimozono K Aoki K Nishiyama H 《Molecules (Basel, Switzerland)》2011,16(7):5387-5401
Bis(oxazolinyl)phenylrhodium(III) aqua complexes, (Phebox)RhX?(H?O) [X = Cl, Br], were found to be efficient Lewis acid catalysts for the enantioselective addition of allyl- and methallyltributyltin reagents to amino aldehydes. The reactions proceed smoothly in the presence of 5-10 mol % of (Phebox)RhX?(H?O) complex at ambient temperature to give the corresponding amino alcohols with modest to good enantioselectivity (up to 94% ee). 相似文献
18.
Y. Muramatsu H. Kouzuki T. Kaneyoshi M. Motoyama A. Agui S. Shin H. Kato J. Kawai 《Applied Physics A: Materials Science & Processing》1997,65(2):191-194
* –B1s-1 transitions were observed in w-BN composed of four-fold boron atoms and in h-BN composed of three-fold boron atoms, when
the photon energy of the incident undulator beams coincided with the B1s–B2pπ* absorption energy. However, no resonance was observed in c-BN composed of four-fold boron atoms. The resonant X-ray emission
reflects the electronic structure of unoccupied molecular orbitals which strongly depend on the conformnations of the boron
atoms. These findings confirm that resonant X-ray emissions can be useful indices for molecular and electronic structure analysis
of boron nitrides.
Accepted: 6 March 1997 相似文献
19.
Irradiation of graphite fluoride with electron beams has been carried out on a electron probe microanalyzer. Radiation-induced decomposition took place predominantly instead of thermal decomposition. The decomposition tended to occur in the following order: powdery (CF)n, white flaky (CF)n, and (CF2F)n. The kinetics of the decomposition reaction induced by electron beams was evaluated by the ZAF correction of the measured intensities of F K- and C K-emission bands. It was found that the kinetic of the decomposition of graphite fluoride was of Avrami-Erofejev type; the rate equations were for (CF)n and -ln(1?α)=kt2 for (C2F)n. An application to the electron microbeam processing of graphite fluoride was suggested in relation to its unique physicochemical properties. 相似文献
20.
Toyoki Matsuyama 《Physics letters. [Part B]》1985,158(3):255-263
Toward the construction of the gauge theory on a lattice without species doubling, we formulate the U(1) gauge-coupled Dirac equation on a finite element in (d + 1)-dimensional space-time. For massless (QED)2, we derive the vector current conservation and the axial anomaly. The reproduction of the axial anomaly indicates the resolution of the doubling problem. 相似文献