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221.
Tadahiro Nakamoto Motomi Katada Satoshi Kawata Susumu Kitagawa Hirotoshi Sano Michiko Konno 《Hyperfine Interactions》1994,93(1):1567-1572
Mixed-valence trinuclear iron propionates [Fe
2
III
FeIIO(C2H5CO2)6(py)3]npy, wheren=0, 1.5, were synthesized and the structure of the pyridine-solvated complex was determined by single-crystal X-ray diffraction. Mössbauer spectra of the solvated propionate complex showed a temperature-dependent mixed-valence state related to phase transitions, reaching an almost delocalized valence state at room temperature. On the other hand, the non-solvated propionate showed a remarkable change of the spectral shape related to a phase transition, remaining in a localized valence state at higher temperatures up to room temperature. 相似文献
222.
223.
Proliferation of human leukemia cells, HL60, was synergistically inhibited by a combination of human interferons and azidothymidine in vitro. Combination of interferon-gamma (3000 U/ml) and azidothymidine (30 microM) inhibited cell growth by 76%, whereas interferon-gamma alone suppressed growth by 23% and azidothymidine alone by 33%. Interferon-alpha-2a and interferon-beta also exerted synergistic effects with azidothymidine, but the potentiation was weaker than that by the combination of interferon-gamma and aziodthymidine. 相似文献
224.
225.
Shigeharu Onogi Tadahiro Asada Akira Tanaka 《Journal of Polymer Science.Polymer Physics》1969,7(1):171-182
To clarify the deformation mechanism in polyblends of polypropylene with ethylene–propylene rubber having different compositions, simultaneous measurements of the infrared dichroism with stress and strain under a constant rate of strain of 1.64%/min have been carried out. The orientation function of the crystallographic c axis of polypropylene in the blends has been obtained as a function of strain ranging from 0 to 20% and of polypropylene content ranging from 0.3 to 1.0. These results have been compared with the temperature dependences of the dynamic Young's modulus and of the loss modulus, as well as of stress–strain curves for the same blends. The modulus data analyzed by Kerner's equation reveal the occurrence of phase inversion at polypropylene contents higher than about 0.5, and this is supported by the infrared dichroism data. The strong effect of quenching on crystalline structure and mechanical properties of pure polypropylene has also been elucidated. 相似文献
226.
227.
Jun'ichi Katakawa Tadahiro Tetsumi Tadamasa Terai Masaaki Katai Ken-ichi Sakaguchi Mamoru Sato 《Journal of chemical crystallography》2000,30(9):573-576
The crystal and molecular structure of a grayanotoxin VII is presented. The crystal is monoclinic, space group P21, with a = 7.647(1) Å, b = 11.7591(7) Å, c = 10.0873(6) Å, = 91.143(8)°, V = 906.9(1) Å3, Z = 2. The structure was solved by direct methods and refined by full-matrix least-squares methods to a final R = 0.057 for 1494 independent reflections. The molecule has a tetracyclic structure consisting of two five-membered, one six-membered, and one seven-membered rings. 相似文献
228.
Emi Minamitani Noriaki Takagi Ryuichi Arafune Thomas Frederiksen Tadahiro Komeda Hiromu Ueba Satoshi Watanabe 《Progress in Surface Science》2018,93(4):131-145
Inelastic electron tunneling spectroscopy (IETS) combined with scanning tunneling microscopy (STM) allows the acquisition of vibrational signals at surfaces. In STM-IETS, a tunneling electron may excite a vibration, and opens an inelastic channel in parallel with the elastic one, giving rise to a change in conductivity of the STM junction. Until recently, the application of STM-IETS was limited to the localized vibrations of single atoms and molecules adsorbed on surfaces. The theory of the STM-IETS spectrum in such cases has been established. For the collective lattice dynamics, i.e., phonons, however, features of STM-IETS spectrum have not been understood well, though in principle STM-IETS should also be capable of detecting phonons. In this review, we present STM-IETS investigations for surface and interface phonons and provide a theoretical analysis. We take surface phonons on Cu(1?1?0) and interfacial phonons relevant to graphene on SiC substrate as illustrative examples. In the former, we provide a theoretical formalism about the inelastic phonon excitations by tunneling electrons based on the nonequilibrium Green’s function (NEGF) technique applied to a model Hamiltonian constructed in momentum space for both electrons and phonons. In the latter case, we discuss the experimentally observed spatial dependence of the STM-IETS spectrum and link it to local excitations of interfacial phonons based on ab-initio STM-IETS simulation. 相似文献
229.
Tadao Uyehara Yasuhiro Kabasawa Tadahiro Kato Toshiaki Furuta 《Tetrahedron letters》1985,26(19):2343-2346
The total synthesis of (±)-pinguisone and (±)-deoxopinguisone, the unusual [5–6], fused-ring sesquiterpenes, was accomplished by the photochemical transformation of the bicyclo [3.2.2]non-6-en-2-one into the bicyclo [4.3.0]non-4-en-7-one. 相似文献
230.
The property of hole capture of quantum wells is important in the static properties of lasers above threshold, such as the differential efficiency and light output power. We investigate experimentally the hole capture rate and its influence on the carrier overflow in the optical confinement layers for compressive-strained, tensile-strained and unstrained GaInAs/GaInAsP/InP quantum-well lasers emitting at 1.5 m by measuring the spontaneous emission from the optical confinement layers above threshold. The carrier density in the optical confinement layers increases with current owing to finite hole capture rates. This increase is dependent on well thickness and barrier height determined by the strain. This increase is comparable in the tensile-strained and unstrained lasers with relatively low threshold, while in the compressive-strained laser it is about double that in the other two types. The dependence of this increase on threshold carrier density is also observed, that is the carrier density in the optical confinement layers increases rapidly in high-threshold samples, in particular, in the tensile-strained laser with large hole barrier height. From these results, laser operation with high output power and high efficiency is expected by reducing threshold carrier density in the tensile-strained laser and by increasing well numbers in the compressive-strained laser as long as the inhomogeneous injection between wells is not severe. By fitting measurements with theory, the hole capture time is estimated as 0.1 to 0.25 ps in these strained and unstrained lasers. 相似文献