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51.
Ayako Tokiwa Masayasu Nagoshi Yasuhiko Syono 《Physica C: Superconductivity and its Applications》1990,170(5-6):437-442
Superconductivity and composition analysis of PbBaSr(Y, Ca)Cu3Oy with fixed ratio of Sr/Ba = 1 were studied. Synthesis condition and superconductivity of Pb(Ba, Sr)2(Y, Ca)Cu3Oy with various ratio of Sr/Ba and Ca/Y were also studied. It was found that Tc increased with increasing Ca concentration, and that Sr-rich specimens allowed to contain more Ca. PbBa0.8Sr1.2Y0.6Ca0.4Cu3O7 showed superconductivity with zero-resistance temperature of 42 K, which was higher than PbBaSrY0.7Ca0.3Cu3O7 with maximum Ca content for Sr/Ba = 1. Decrease in averaged ionic radii of Ba and Sr in Sr-rich compositions would be favorable for the contraction of Cu-O bonds by hole-doping via Ca substitution for Y. 相似文献
52.
Tomohiko Sato Toshihiko Nakaoka Makoto Kudo Yasuhiko Arakawa 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):152
We have investigated magneto-optical properties of GaSb/GaAs self-assemble type II quantum dots by single dot spectroscopy in magnetic field. We have observed clear Zeeman splitting and diamagnetic shift of GaSb/GaAs quantum dots. The diamagnetic coefficient ranges from 5 to 30 μeV/T2. The large coefficient and their large distribution are attributed to the size inhomogeneity and electron localization outside the dot. The g-factor of GaSb/GaAs quantum dots is slightly larger than that of similar type I InGaAs/GaAs quantum dots. In addition, we find almost linear relationship between the diamagnetic coefficient and the g-factor. The linear increase of g-factor with diamagnetic coefficient is due to an increase of spin-orbit interaction with dot size. 相似文献
53.
Makoto Kudo Tomoyoshi Mishima Satoshi Iwamoto Toshihiro Nakaoka Yasuhiko Arakawa 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):275
Self-assembled GaSb quantum dots (QDs) with a photoluminescence wavelength longer than 1.3 μm were successfully grown by suppressing the replacement of As and Sb on the surface of the GaSb QDs. This result means that GaSb can thus join InAs or GaInAs as a suitable material for QD lasers for optical communications. 相似文献
54.
55.
The empirical energy parameters for a calcium ion and its ligands in proteins were determined within a pairwise additive framework. The interaction energies of Ca2+-water, Ca2+-peptide group and Ca2+-carboxyl group systems were calculated using the ab initio molecular orbital method with basis sets of double zeta quality including polarization or diffuse functions. The resulting potential energy surfaces served as references for the determination of the nonbonded parameters in the empirical energy function. The nonadditive corrections for the Ca2+-ligand pair potentials are incorporated implicitly in the nonbonded paremeters by treating three-body (1:2 complex) or seven-body (1:6 complex) systems in reference calculations. Ligand polarizations induced by Ca2+ are estimated from the partial atomic charges of two-body (1:1 complex) systems. The charge sets were determined by scaling so as to reproduce the reference potential energy surfaces. The newly determined parameter set was used in a stochastic boundary molecular dynamics simulation of phospholipase A2. The solvated structure of the Ca2+-binding site obtained from an X-ray crystallographic study is well reproduced by the parameter set. 相似文献
56.
57.
Reversible waves of voltammetry with complex non-unity stoichiometry are studied here based on theory. Numerical simulations
were performed for various stoichiometric systems in which coefficients m and q were independently varied from 1 to 4 in a general reaction scheme, mO + ne− ai qR. The calculation results indicate that the peak current function at complex stoichiometry differs from that at simple unity
stoichiometry. The relation between the half-wave potential and the formal potential has been partially corrected from that
previously reported in the literature. Parameters in the relation between the peak potential and the half-wave potential are
unique for each stoichiometric system. The parameter in the relation between the peak potential and the half-peak potential
is also presented here. 相似文献
58.
Kazuhiko Hosomi Toshihiko Fukamachi Hiroji Yamada Toshio Katsuyama Yasuhiko Arakawa 《Photonics and Nanostructures》2006,4(1):30-34
We demonstrate optical properties of one-dimensional photonic crystals (PC), which are fabricated using high-aspect-ratio etching on a V-grooved silicon wafer. The measured transmission spectrum has an obvious band gap; the suppression is over 30 dB. The quite small insertion loss of 1.9 dB is achieved by induced coupled plasma (ICP) cryogenic etching and direct coupling to the optical fiber aligned in the V-groove. We also successfully observed peaks originating from a localized cavity mode. Such a microcavity enables control of the light, which qualifies photonic crystal as a fundamental structure of optical functional devices. These results lead to achievement of integrated Si-based photonic circuits. 相似文献
59.
We give a birational realization of affine Weyl group of type A
(1)
m–1 × A
(1)
n–1. We apply this representation to construct some discrete integrable systems and discrete Painlevé equations. Our construction has a combinatorial counterpart through the ultra-discretization procedure. 相似文献
60.
This paper deals with a probabilistic formulation of the wave scattering from a periodic random surface. When a plane wave is incident on a random surface described by a periodic stationary stochastic process, it is shown by a group-theoretic consideration that the scattered wave may have a stochastic Floquet form, i.e. a product of a periodic stationary random function and an exponential phase factor. Such a periodic stationary random function is then written by a harmonic series representation similar to a Fourier series, where Fourier coefficients are mutually correlated stationary processes instead of constants. The mutually correlated stationary processes are represented by Wiener - Hermite functional series with unknown coefficient functions called Wiener kernels. In case of a slightly rough surface and TE wave incidence, low-order Wiener kernels are determined from the boundary condition. Several statistical properties of the scattering are calculated and illustrated in figures. 相似文献