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81.
CuO nanowires have been synthesized by heating a Cu foil in an ambient condition. The diameters of nanowires can be controlled by changing the annealing temperature. The morphology, composition, and structure were analyzed by using X-ray diffraction (XRD) and scanning electron microscope (SEM). To investigate the detailed layering structure of the substrates after oxidation, the cross-sectional analysis was also performed by using field emission-SEM and energy dispersive X-ray spectroscopy (EDX). The EDX measurements indicated that the CuO nanowires were grown on the CuO/Cu2O layer, which was formed on the surface of Cu foil. 相似文献
82.
An integral representation of the Meixner–Pollaczek polynomials is presented in terms of a multidimensional generalization of the Barnes type integral. Motivation consists in the study of the Barnes type integrals from the viewpoint of a finite-difference version of the de Rham theory. 相似文献
83.
Katsuhisa Ohta 《International journal of quantum chemistry》2013,113(2):161-170
In this work, we consider two conditions required for the nonsingularity of constraints in the time‐dependent variational principle (TDVP) for parametrized wave functions. One is the regularity condition which assures the static nonsingularity of the constraint surface. The other condition is the second‐class condition of constraints which assures the dynamic nonsingularity of the constraint surface with a symplectic metric. For analytic wave functions for complex TDVP‐parameters, the regularity and the second‐class conditions become equivalent. The second‐class condition for expectation values is reduced to the noncommutability of the corresponding quantum operators. The symplectic singularity of the equation of motion of TDVP is also shown to be a local breakdown of the second‐class condition in an extended canonical phase‐space. © 2012 Wiley Periodicals, Inc. 相似文献
84.
85.
Satoshi Suzuki Katsuhisa Furuta Shoshiro Hatakeyama 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(4):371-395
Passive walking emerges autonomously on a slight slope without an external input of energy. It is known that the walking motion on a steep slope evolves into a chaotic motion. In this paper a biped model for walking and running is presented, and a strategy is proposed to expand the range of stable passive walking by using a chaos-control technique based on the Ott?–?Grebogi?–?Yorke method. The resultant controller is a discrete type so that the input value changes at every step, and the generated walking motion is kept non-chaotic. Fast walking on a steep slope is achieved, and pseudorunning has also been realized in simulations. By adding an input to the biped model, in which the input corresponds to the effect of the artificial gravity field, it has been verified that pseudorunning can be realized on level ground. 相似文献
86.
It is well known that the extended binary Golay [24,12,8] code yields 5-designs. In particular, the supports of all the weight 8 codewords in the code form a Steiner system S(5,8,24). In this paper, we give a construction of mutually disjoint Steiner systems S(5,8,24) by constructing isomorphic Golay codes. As a consequence, we show that there exists at least 22 mutually disjoint Steiner systems S(5,8,24). Finally, we prove that there exists at least 46 mutually disjoint 5-(48,12,8) designs from the extended binary quadratic residue [48,24,12] code. 相似文献
87.
Pradip Ghosh M. Subramanian M. Zamri T. Jimbo M. Tanemura 《Applied Surface Science》2009,255(8):4611-4615
Nitrogen-doped Y-junction bamboo-shaped carbon nanotubes were synthesized by chemical vapor deposition of monoethanolamine/ferrocene mixture on GaAs substrate at 950 °C. The use of monoethanolamine as the C/N feedstock simplifies the experimental arrangement by producing ammonia during the growth process. The structure, morphology and graphitization of as-grown nitrogen-doped carbon nanotubes (CNx) were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy analysis. TEM analysis indicates that nanotubes have a bamboo-like structure. The nitrogen concentration on as-grown CNx nanotube was found to be 7.8 at.% by X-ray photoelectron spectroscopy (XPS) analysis. XPS analysis also indicated that there are two different types of nitrogen atoms (pyridinic and graphitic) in these materials. The possible growth mechanism of formation of Y-junction CNx nanotubes was briefly discussed. Field emission measurement suggested that as-grown CNx nanotubes are excellent emitters with turn-on and threshold fields of 1.6 and 2.63 V/μm, respectively. The result indicated that monoethanolamine proves to be an advantageous precursor to synthesize Y-junction nitrogen-doped carbon nanotubes and such nanotubes might be an effective material to fabricate various field emission devices. 相似文献
88.
Katsuhisa Tanaka Koji Fujita Hajime Hojo 《Journal of magnetism and magnetic materials》2009,321(7):818-821
We have synthesized thin films of disordered zinc ferrite (ZnFe2O4) and ilmenite-hematite (FeTiO3-Fe2O3) solid solution, the former and the latter of which are interesting from the viewpoints of magnetooptics and spintronics, respectively, by utilizing sputtering and pulsed laser deposition methods, and have explored their magnetic, magnetooptical, and electrical properties. Although ZnFe2O4 possesses a normal spinel structure as its stable phase, some of the Fe3+ ions occupy the tetrahedral as well as the octahedral sites in ZnFe2O4 of which the sputtered thin film is composed. Consequently, the as-deposited thin film manifests large magnetization even at room temperature although the magnetic phase transition temperature of the stable phase of ZnFe2O4 is as low as 10 K. Also, the thin film exhibits a cluster spin glass transition at a temperature as high as 325 K. Furthermore, the ZnFe2O4 thin films exhibit large Faraday effects at a wavelength of 400 nm or so. The ilmenite-hematite solid solution is one of the ferrimagnetic semiconductors. Most of the compositions possess Curie temperatures higher than room temperature, and the type of carrier can be tuned only by changing the composition. We have succeeded in synthesizing solid-solution thin films of various compositions grown epitaxially on sapphire substrates with a (0 0 0 1) plane, and have shown that the thin films are ferrimagnetic semiconductors. 相似文献
89.
Koichi Nakade Masamitsu Ohnishf Toshihide Ibaraki Katsuhisa Ohno 《Queueing Systems》1992,11(3):241-254
We consider a parallel queueing system with identical exponential servers. Customers arrive according to a renewal process and upon arrival are immediately assigned to those queues. The problem is to find an optimal assignment policy minimizing the longrun average expected cost, without information about the current queue lengths, but with the initial queue-length distributions and information about the past arrival process and assignment of customers. In this paper, it is shown that the so-called circular assignment policy is optimal under mild conditions on the initial queue-length distributions and the holding cost. 相似文献
90.
Masakazu Jimbo 《Aequationes Mathematicae》1983,26(1):184-190
A Steiner 2-design S(2,k, v) is said to be 1-rotational if it admits an automorphism whose cycle structure is a (v ? 1)-cycle and a fixed point. In this paper, a recursive construction of 1-rotational Steiner 2-designs is given. 相似文献