JaLCDOI 10.18926/15436
フルテキストURL Mem_Fac_Eng_OU_26_2_69.pdf
著者 Fujii, Tatsuo| Sakata Naoki| Nanba, Tokuro| Osaka, Akiyoshi| Miura, Yoshinari| Takada, Jun|
抄録 (001)-oriented Ti(2)O(3) films were epitaxially grown on a(001)-face of sapphire single-crystalline substrate by an activated reactive evaporation method. The formation ranges of stoichiometric and nonstoichiometric Ti(2)O(3) films were determined as a function of the substrate temperature (Ts), the oxygen pressure (Po(2)) and the deposition rate. Stoichiometric Ti(2)O(3) films were grown at Ts≧673K under Po(2)≧1.0×10(-4)Torr, which showed the metal-insulator transition with a sharp change in electrical resistivity from 3.5×10(-2) to 2.6×10(-3)Ωcm at 361K. Nonstoichiometric films prepared under less oxidized conditions did not exhibit the transition. The nonstoichiometry of the Ti(2)O(3)films was discussed in terms of excess Ti ions.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1992-03-28
26巻
2号
開始ページ 69
終了ページ 75
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307639
JaLCDOI 10.18926/19608
フルテキストURL Mem_Fac_Eng_OU_33_1_19.pdf
著者 鷲尾 誠一| 高橋 智| 井元 智可至| 吉田 篤正|
抄録 The present paper deals with measurements of the diffusion coefficients as well as the saturated solubilities of single component gases such as N(2), O(2) and CO(2) to a mineral oil. The method to determine the diffusivity is based upon measuring the pressure changes caused by the one-dimensional diffusion between the gas and the oil enclosed in an airtight container. For N(2) and O(2) the profiles of the measured pressure changes agree well with those predicted by diffusion theory, whereas that is not the case with CO(2). Although the reason why CO(2) does not seem to obey diffusion theory has yet to be studied, it may suggest the possibility that the diffusion coefficient varies with the pressure, considering that the range of pressure change in the diffusivity measurement was much obtained by this method fell within ±30% around the average. Moreover the solubility measurements have made clear that Henry's law holds true between the three pure gases and the oils tested, and that O(2) and CO(2) dissolve into the oil approximately two and ten times more, respectively, than N(2).
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1998-11-30
33巻
1号
開始ページ 19
終了ページ 30
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002309030
JaLCDOI 10.18926/20011
フルテキストURL Mem_Fac_Eng_OU_29_1_7.pdf
著者 Hiroyuki Tachibana| 東辻 浩夫| 奈良 重俊| 東辻 千枝子|
抄録 Effects of interface fluctuations on the electronic states in semiconductor quantum dots are analyzed on the basis of numerical solutions for ground state wave functions and energy eigenvalues. It is shown that the effective volume of confinement becomes smaller than the real volume of quantum dots due to fluctuation. This effect comes from the fact that the wave functions with larger characteristic wavelength are not able to deform themselves following the fluctuation of interfaces exactly.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1994-11-30
29巻
1号
開始ページ 7
終了ページ 14
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002310741
JaLCDOI 10.18926/15460
フルテキストURL Mem_Fac_Eng_OU_28_2_45.pdf
著者 東辻 浩夫| 橋本 成仁| 奈良 重俊|
抄録 Difficulties in simulating systems composed of classical and quantum particles lie in the treatment of the many-body interactions between quantum particles and the geometrical variety of configurations of classical particles. In order to overcome these difficulties, we have developed some numerical methods and applied them to simple cases. As for stationary states, the finite element method provides us with sufficient geometrical freedom. Combined with the Kohn-Sham equation based on the density functional theory, this method virtually satisfies our requirement. In order to investigate time-dependent phenomena, we apply the time-dependent Kohn-Sham equation. Adopting the finite difference method, we are able to follow the development of quantum many-body system. As an example, we estimate the effects of the potential height, the electric field, and many-body interactions in some transition processes in quantum wells coupled by a tunneling barrier. This example is important in itself in relation to semiconductor superlattices and also serves as a benchmark for quantum simulations, variety of geometry corresponding to that of classical particles.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1994-03-15
28巻
2号
開始ページ 45
終了ページ 52
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307158
JaLCDOI 10.18926/15443
フルテキストURL Mem_Fac_Eng_OU_26_2_111.pdf
著者 奈良 重俊| Banzhaf Wolfgag|
抄録 An information processing task which generates combinatorial explosion and program complexity when it is treated by a serial algorithm is investigated using both Genetic Algorithms (GA) and a neural network model (NN). The task in question is to find a target memory from a set of stored entries in the form of "attractors" in a high dimensional state space. The representation of entries in the memory is distributed ("an auto associative neural network" in this paper), and the problem is to find an attractor under a given access information where the uniqueness or even existence of a solution is not always guaranteed ( an ill-posed problem ). The GA is used as an algorithm for generating a search orbit to search effectively for a state which satisfies the access condition and belongs to the target attractor basin in state space. The NN is used to retrieve the corresponding entry from the network. The results of our computer simulation indicate that the present method is superior to a search method which uses random walk in state space. Our technique may prove useful in the realization of flexible and adaptive information processing, since pattern search in high dimensional state spaces is common in various kinds of parallel information processing.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1992-03-28
26巻
2号
開始ページ 111
終了ページ 128
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307718
JaLCDOI 10.18926/15434
フルテキストURL Mem_Fac_Eng_OU_28_1_27.pdf
著者 東辻 浩夫| Tachibana Hiroyuki| Fujimura Hidenori| 奈良 重俊|
抄録 The ground states of interacting electrons in coupled quantum wires are analyzed on the basis of the density functional theory. The exchange-correlation potential is calculated from 'exact' results given by the Green's function Monte Carlo method in two and three dimensions. It is shown that the critical density signifying the change from symmetrical to asymmetrical ground state is weakly dependent on the details of the exchange-correlation potential. These critical values are compared with the result of the three-dimensional analysis for a single wire.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1993-11-30
28巻
1号
開始ページ 27
終了ページ 38
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307565
JaLCDOI 10.18926/15432
フルテキストURL Mem_Fac_Eng_OU_28_1_1.pdf
著者 奈良 重俊| Miho Shigeru| 東辻 浩夫|
抄録 The structural stabilities of bulk Si, Ge, and GaAs are discussed based on the total energy evaluated by the summation of the band structure energy and the short-range repulsive potential between ions. The band structure energy is calculated by means of the simple tight-binding method. The tight-binding parameters are determined so as to fit to the results of a pseude potential calculation and Harrison's model is employed to include the influence of lattice deformation. The short-range-force is assumed to be of the exponential form and parameters are determined so as to reproduce an experimental value of bulk modulus. This treatment qualitatively well describes structural properties in spite of the simple computational procedure and roughly gives the known variation of the total energy for a <100> uniaxial strain. This method is able to be applied to an investigation of the structural stabilities of superlattices, for example, a strained layer superlattice consisting of hetero-semiconductors.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1993-11-30
28巻
1号
開始ページ 1
終了ページ 25
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307238
JaLCDOI 10.18926/15418
フルテキストURL Mem_Fac_Eng_OU_26_1_51.pdf
著者 東辻 浩夫| Shirokoshi Hideki| 奈良 重俊|
抄録 Variable shape molecular dynamics is formulated for the one-component plasma and the structural transition from the fcc lattice to the bcc lattice has been observed. It is emphasized that the condition of constant volume should be imposed when deformations of periodic boundary conditions are taken into account.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1991-11-30
26巻
1号
開始ページ 51
終了ページ 59
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307555
JaLCDOI 10.18926/15403
フルテキストURL Mem_Fac_Eng_OU_27_2_19.pdf
著者 奈良 重俊| 東辻 浩夫|
抄録 Numerical simulations of a single layer recurrent neural network model in which the synaptic connection matrix is formed by summing cyclic products of succesive patterns show that complex dynamics can occur with the reduction of a connectivity parameter which is the number of connection between neurons. The structure in these dynamics is discussed from the viewpoint of realizing complex function using complex dynamics.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1993-03-25
27巻
2号
開始ページ 19
終了ページ 40
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307451
JaLCDOI 10.18926/15395
フルテキストURL Mem_Fac_Eng_OU_27_1_65.pdf
著者 奈良 重俊| Hara Yuji| 東辻 浩夫|
抄録 Quantum mechnical electron wave transfer between two quantum wires which are weakly coupled via a thin potential barrier is considered. The total electronic states are calculated with both analytical ( no field case ) and numerical methods ( under applied electric fields ). The transfer efficiency is evaluated for several specified cases of geometrical structures, potential barrier heights and the externally applied electric field. Estimated trasfer time is of the order of one picosecond in typical mesoscopic structures. The model in this paper can be used to determine important structure parameters for experiments on electron directional coupler controled by external elctric field.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1992-11-25
27巻
1号
開始ページ 65
終了ページ 79
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307405
JaLCDOI 10.18926/15394
フルテキストURL Mem_Fac_Eng_OU_27_1_55.pdf
著者 東辻 浩夫| Tachibana Hiroyuki| Hashimoto Seiji| 奈良 重俊|
抄録 The ground state of a system of electrons accumulated in a pair of coupled symmetric quantum wires is analyzed on the basis of density functional theory. It is shown that, in a domain of physical parameters, electrons are localized in either of wires. The main contribution to the total energy of this system comes from the Hartree energy, or the electrostatic energy, and the exchange-correlation energy between electrons. The ground state is determined by a competition between these contributions: We have symmetric electron distributions when the Hartree energy dominates and asymmetric (localized) states are realized in the opposite case. This kind of simple system with bistable electronic states may be applied to semiconductor memory devices.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1992-11-25
27巻
1号
開始ページ 55
終了ページ 64
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307892
JaLCDOI 10.18926/15381
フルテキストURL Mem_Fac_Eng_OU_30_1_75.pdf
著者 東辻 浩夫| 井上 嘉彦| 岸本 篤也| 東辻 千枝子| 奈良 重俊|
抄録 Molecular dynamics of the Yukawa system, the system of particles interacting via the Yukawa or the screened Coulomb potential, are formulated for various statistical ensembles and external conditions. The Yukawa potential smoothly interpolates the long-range Coulomb and the short-range interactions by adjusting a single parameter, the screening length. In order to reduce the effect of boundaries, the periodic boundary conditions are imposed and the deformations of the fundamental vectors of periodicity are taken into account. Ewald-type expressions for interaction energy, force, and kinematic pressure are given explicitly.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1995-12-28
30巻
1号
開始ページ 75
終了ページ 87
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307479
JaLCDOI 10.18926/19648
フルテキストURL Mem_Fac_Eng_OU_33_2_1.pdf
著者 Omura, Yasuhiro| 飛田 守孝| 榊原 精| 竹元 嘉利|
抄録 Molecular dynamics simulation of nickel crystal under uniaxial tensile and compressive deformation was performed for single nenocrystal model and twinned nanocrystal model composed of 1550 atoms using EAM (embedded atom method) potential with the object of investigating deformation induced phase tranformation (especially twin deformation). In the case of single nanocrystal model, the evolution and development of twin deformation, (111)[11(2)], is observed under compressive loading in [001] direction, whereas either slip or twin deformation is not recognized under tensile loading. In the case of twinned nanocrystal model, twin, (111)[11(2)], decreases and disappears under tensile loading, and develops under compressive loading, It is suggested from the difference of results between single nanocrystal model and twinned nanocrystal model that it is easy for twin to induce local deformation.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1999-04-27
33巻
2号
開始ページ 1
終了ページ 8
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002309020
JaLCDOI 10.18926/19589
フルテキストURL Mem_Fac_Eng_OU_31_2_11.pdf
著者 Ishii Kouta| 竹元 嘉利| 飛田 守孝|
抄録 Fine particles of Ti-V alloy were prepared by means of arc method and were investigated on internal structure and phase transformation using HR-TEM and EDS. Martensite phase was observed in a particle containing comparatively low concentration of V, and ω phase was also found to exist in a nearly 15% V particle. The structure of the ω phase in the fine particle is remarkably expanded in comparison with the bulk sample, and the ω phase is unstable, so that it has disappeared in a few seconds during TEM observation.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1997-03-28
31巻
2号
開始ページ 11
終了ページ 20
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002309004
JaLCDOI 10.18926/19588
フルテキストURL Mem_Fac_Eng_OU_31_2_1.pdf
著者 Arisawa Hideaki| Song Zhi-Yi| 竹元 嘉利| 飛田 守孝|
抄録 The microstructure of oxidizing magnesium at elevated temperatures has been studied using HR-TEM, SEM and EDS. Two kinds of thin magnesium specimen for TEM observation were prepared. One was oxidized after preparing TEM foil of magnesium, the other was prepared from an oxidized bulk magnesium for observing the cross-section of oxide/Mg interfacial region. In the former, several oxides(MgO) morphologies were observed depending on the temperature and time of the oxidization. The growth of needle-like oxides formed at 573K and mottled oxides formed at 773K were recognized as a remarkable phenomenon belonging to the local oxidization. These oxides were composed of poly-crystal. The thin uniform oxidization layer was also observed in all conditions. In the cross-sectional observation, the local oxide layer, nearly 300nm in thickness, on the matrix(Mg) were observed. The thin uniform oxidized layer of bulk samples was identified as a kind of modified layer (~40nm in thickness) in which the formation of HR-TEM lattice fringes were prevented by the strain due to the slight oxidization.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1997-03-28
31巻
2号
開始ページ 1
終了ページ 10
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002309082
JaLCDOI 10.18926/15505
フルテキストURL Mem_Fac_Eng_OU_24_2_89.pdf
著者 横平 徳美|
抄録 This paper considers a test set for an ALU with look ahead carry generators(LCGs). The ALU is logically partitioned into two groups of blocks, the group of one-bit operation units and LCG group. Each group is tested in parallel and exhaustively, independent of the other. And an easily testable design is applied to several blocks for decreasing the number of the input combinations of them. Under the easily testable design, a minimum test set for each group is generated, and the upper and lower bounds for a minimum test for the ALU are derived. The difference of the lower and upper bounds is not large, and a test set whose number of test vectors is equal to the upper bound can be easily obtained as the union of minimum test sets for two groups. Hence, the union can be used as a complete and practical test set for the ALU.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1990-03-29
24巻
2号
開始ページ 89
終了ページ 98
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307212
JaLCDOI 10.18926/15489
フルテキストURL Mem_Fac_Eng_OU_24_2_1.pdf
著者 Umemoto, Masayuki| 竹元 嘉利| 榊原 精| 飛田 守孝|
抄録 Fine particles of Ti-Mo alloy were prepared by evaporation. When Ti-40at % Mo alloy was evaporated on tungsten filament, fine particles of Ti contaminated with W were obtained. These particles were polyhedron in shape and 10~250nm in diameter. Average diameter and size distribution increased with pressure of argon gas (100~600 Torr). When pure Ti was placed on the Mo filament and evaporated from melt down of heated Mo filament in helium gas, fine particles of pure Ti and of Ti-Mo alloy were obtained. In this case, Ti particles were of indeterminate form and of several tens nm in diameter, and their diffraction pattern was of common α-Ti. On the other hand, composition of the Ti-Mo particles was determined to be 18at % Mo by an analysis of EDX. Structure of Ti-Mo particles could not be determined because their diameters were more than 600nm. The temperature of Mo filament, for the most part, was about 1800℃, and there pure Ti particles were produced. The temperature of the fused part of the filament was locally higher than 2600℃, and there Ti-Mo particles were produced. Fine structures of contact region among some Ti particles were observed with HRTEM.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1990-03-29
24巻
2号
開始ページ 1
終了ページ 9
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307765
JaLCDOI 10.18926/15453
フルテキストURL Mem_Fac_Eng_OU_28_2_13.pdf
著者 Kusumoto, Hisao| 飛田 守孝| 榊原 精| Nishida, Norihide| 竹元 嘉利| 山田 益男|
抄録 The strain in Si substrate induced by locally ion-plated thin film of TiN was observed by X-ray topograph (Lang technique). Circular TiN film was deposited on one side of the Si surface. In all topographs the highest blackness attributed to kinematical diffraction effect occurred at the film edge. Rosette pattern with four-lobes was observed around the film. Blackness as a whole increased with the film thickness. Strain was observed in the depth direction of substrate by limited projection method. When the slit width was narrowed, the kinematical images disappeared, and white images appeared at the film edge. All the contrast disappeared when the TiN film was completely removed in boiling HNO(3). The strain induced by the film deposition was proved to be elastic.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1994-03-15
28巻
2号
開始ページ 13
終了ページ 20
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307150
JaLCDOI 10.18926/15448
フルテキストURL Mem_Fac_Eng_OU_28_2_1.pdf
著者 竹元 嘉利| 榊原 精| 飛田 守孝|
抄録 Fine particles of Ti-Mo alloy have been prepared by means of arc method, and investigated on internal structure and phase transformation using HR-TEM and EDS. Martensite phase was observed in a particle containing comparatively low concentration of Mo, and ω phase was also found to exist in a nearly 14 % M0 particle. The structure of the ω phase in the fine particle is expanded and remarkably unstable in comparison with the bulk sample, so that it has disappeared in a few seconds during TEM observation. Moreover, the β structure of Ti-Mo particles has changed to the unusual fcc phase with irradiation of a strong electron beam.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1994-03-15
28巻
2号
開始ページ 1
終了ページ 7
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307644
JaLCDOI 10.18926/15397
フルテキストURL Mem_Fac_Eng_OU_30_2_1.pdf
著者 竹元 嘉利| 飛田 守孝| 榊原 精|
抄録 The mechanism of brittle fracture in Ti-14mass % Mo alloy aged for 1x10(6)s at 623K was studied using transmission electron microscopy (TEM) and dynamic hardness test (DHT) on the structure deformed by means of tensile elongation at elevated temperature or cold rolling. Many band products were observed by TEM in either deformed specimens. These band products were identified to neither slips nor twinning bands, moreover, they were different from α , α ' and α " phases. The band product consisted of β phase and granular unknown phase which was transformed by deformation from ω phase. The newly discovered phase, named β" phase, in the band products had a body-centered triclinic structure. The β" was similar to the ω zone with respect to the morphology and the concentration of Mo, but it resembled β in structure. The result of DHT on the band products and the matrix showed that the band products were softer than the matrix. It is suggested that the band products are easily deformed because of the disappearance of obstacles such as ω phase, and consequently behave like paths to lead cracks preferentially.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1996-03-29
30巻
2号
開始ページ 1
終了ページ 7
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307225