JaLCDOI 10.18926/19589
FullText URL Mem_Fac_Eng_OU_31_2_11.pdf
Author Ishii Kouta| Takemoto, Yoshito| Hida, Moritaka|
Abstract 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.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1997-03-28
Volume volume31
Issue issue2
Start Page 11
End Page 20
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309004
JaLCDOI 10.18926/19634
FullText URL Mem_Fac_Eng_OU_32_15.pdf
Author Mori, Masahiro| Oka, Hisao|
Abstract In a stiffness estimation of living body, an internal structure under the skin influences the measured results. Because a different stiffness of body caused by bones and muscles is obtained. In this paper, by using a measurement system of mechanical impedance, the relations between a viscoelasticity and a distance from the surface of silicone-gel model is calculated. This relation is applied to silicone-gel tumor model and a shape and a viscoelasticity of semi-sphere silicone-gel tumous are estimated. The obtained results are expressed as a reconstructed 3-D image of shape / viscoelasticity. The revised curve-fitting of mechanical impedance and the cancellation of peripheral vibration influence are proposed in order to increase an estimation acccuracy.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1998-04-20
Volume volume32
Issue issue1-2
Start Page 15
End Page 22
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309047
JaLCDOI 10.18926/15394
FullText URL Mem_Fac_Eng_OU_27_1_55.pdf
Author Totsuji, Hiroo| Tachibana Hiroyuki| Hashimoto Seiji| Nara, Shigetoshi|
Abstract 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.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1992-11-25
Volume volume27
Issue issue1
Start Page 55
End Page 64
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307892
JaLCDOI 10.18926/14152
FullText URL Mem_Fac_Eng_39_1_52.pdf
Author Kanamori, Katsuya| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract Thermal behavior of Coulomb clusters in a three dimensional confining potential is investigated by molecular dynamics simulations for system sizes of 1,000 to 20,288 ions. The specific heat of the system of shell-structured 20,000 ions is peaked almost at the same temperature as the system of bcc-structured 20,288 ions with much sharper structure for the latter. The diffusion coefficient and the peak to valley ratio of the two-dimensional pair distribution function on the outermost shell are obtained both as a function of temperature. The rotational movement of each shell in the system of 104 ions is observed.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2005-01
Volume volume39
Issue issue1
Start Page 52
End Page 55
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308445
JaLCDOI 10.18926/15348
FullText URL Mem_Fac_Eng_OU_35_21.pdf
Author S.kovalenko, Volodymyr| Uno, Yoshiyuki| Okamoto, Yasuhiro| Anyakin, M.| Lutay, A.| Shubul, Khaled Al.|
Abstract In electric power industry, there is a problem of achieving stable joint in different components using high productive and efficient technologies. One type of these components is packages of slices for magnetic circuit of electric motors, transformers etc., which need reliable means for their fixing. Laser welding is proposed to solve this problem as an alternative for existing technologies. The development of the laser welding process is presented based on process simulation, study of heat history and comparison with experimental results. Laser beam additional scanning technique is proposed to improve the quality and efficiency of the joining operation.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 21
End Page 28
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307424
JaLCDOI 10.18926/49322
FullText URL mfe_047_025_032.pdf
Author Nekado, Kenta| Takai, Yusuke| Nogami, Yasuyuki|
Abstract Pairing–based cryptosystems are well implemented with Ate–type pairing over Barreto–Naehrig (BN) curve. Then, for instance, their securities depend on the difficulty of Discrete Logarithm Problem (DLP) on the so–denoted G3 over BN curve. This paper, in order to faster solve the DLP, first proposes to utilize Gauss period Normal Basis (GNB) for Pollard’s rho method, and then considers to accelerate the solving by an adoption of lazy random walk, namely tag tracing technique proposed by Cheon et al.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2013-01
Volume volume47
Start Page 25
End Page 32
ISSN 1349-6115
language 英語
Copyright Holders Copyright © by the authors
File Version publisher
NAID 120005232374
JaLCDOI 10.18926/15408
FullText URL Mem_Fac_Eng_OU_29_2_1.pdf
Author Sakakibara, Akira| Nakagawa, Keiyu| Kanadani, Teruto|
Abstract Effect of addition of a small amount of copper to Al- 12mass % Zn binary alloy on the process of low temperature aging is studied by hardness test and transmission electron microscopy. Age hardening rate after quenching from various temperatures is slowed down by addition of 0.5mass % copper to the binary alloy. The hardness obtained after long aging, however, is increased a little by the addition of copper. The extent of soft surface layer formed by aging in the copper-added alloy is nearly equal to that obtained in the binary alloy.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1995-03-27
Volume volume29
Issue issue2
Start Page 1
End Page 4
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307763
JaLCDOI 10.18926/15502
FullText URL Mem_Fac_Eng_OU_24_2_79.pdf
Author Sato, Yoichiro|
Abstract In asynchronous arbiters, failures may happen, caused by metastable operations. The purpose of this study is to derive a formula to estimate such failures in a ring arbiter as mean time between failures (MTBF), under the condition that incidences of requests issued in all devices are different from each other. The operation of the arbiter is formularized by a markov chain. This chain is used to decide the probability at which each of possible failures contributes to MTBF. The sum of such probabilities gives the MTBF which can be represented as a sum of a finite number of terms. As an example, MTBF of a ring arbiter composed of 3 cells is shown.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-03-29
Volume volume24
Issue issue2
Start Page 79
End Page 87
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307486
JaLCDOI 10.18926/19666
FullText URL Mem_Fac_Eng_OU_33_2_45.pdf
Author Yamada Nobuya| Oka, Hisao|
Abstract It is difficult to evaluate a biomechanical properties quantitatively. The authors developed the measurement system of biomechanical properties formerly but it is on a large scale because of the use of personal computer. In this study, the portable measurement system of biomechanical impedance/mobility is developed. To establish a rapid measurement, a random vibration is adopted in input signal. The system consists of the measuring probe, amplifier, and a note-typed personal computer. The measurement probe is developed newly, and has an overall length of 9 ㎝ (without a handle) and a total weight of about 500 g. The measurement program is also developed and is available to any computer which is worked under MS DOS compatible in Windows 95/98 operating system. The biomechanical spectra of thigh, temple and forehead are obtained and they show three typical spectrum patterns.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1999-04-27
Volume volume33
Issue issue2
Start Page 45
End Page 50
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309193
JaLCDOI 10.18926/15446
FullText URL Mem_Fac_Eng_OU_22_1.pdf
Author Oka, Hisao| Yamamoto, Tatsuma|
Abstract Biomechanical impedance is relatively small compared to industrial mechanical impedance. Thus it is difficult to measure it precisely. A biomechanical impedance measuring system was developed for portable use by means of random excitation. This system doesn't require a fixed body and vibrator supporting apparatus. In order to obtain an impedance spectrum, the FFT processing is performed using a personal computer. The spectra of the biomechanical impedance which is measured on body surfaces depend on body positions and can be roughly classified into three spectra patterns : soft, stiff and intermediate. During the measurement, the measuring conditions (preload, diameter of the vibrating tip etc.) influence the results. However, it became clear that the linearity of the biomechanical impedance was satisfied in the limited measuring conditions. Accordingly it is possible to standardize the impedance and to compare it with the results under different measuring conditions.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1988-03-31
Volume volume22
Start Page 1
End Page 14
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307480
JaLCDOI 10.18926/15476
FullText URL Mem_Fac_Eng_OU_24_1_63.pdf
Author Yamamoto, Yoshitake| Isshiki Hiromi| Oka, Hisao| Yamamoto, Tatsuma|
Abstract There is no doubt that many people feel the peace of mind or the pleasures of senses in appreciating music. But the estimation of the effect is very difficult and the objective estimation can be hardly done. This study proposed the objective estimating method of human emotion utilizing galvanic skin reflex (GSR) which reflects a human psychological activity. In this method, not by individual response, but by the series of response and pattern of appearance of GSR, the emotional response under appreciating music was investigated. In the case of appreciation of the same classic music to several subjects, the individual GSR responses are random and remarkable characteristic could not be find on the results. However, on the patterns of appearance of GSR, the patterns obtaining from the same generation are much similar each other and the patterns obtaining from different generation are less similar. It was cleared that the same music gave different effect on different generations.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1989-11-29
Volume volume24
Issue issue1
Start Page 63
End Page 72
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307670
JaLCDOI 10.18926/15392
FullText URL Mem_Fac_Eng_OU_27_1_45.pdf
Author Kagawa, Naoki| Wada, Osami| Hai, Xu| Koga, Ryuji| Sano, Hiroya| Inubushi, Kazuyuki|
Abstract A prototype device based on the tunable diode laser absorption spectrometry was constructed and the atmospheric methane concentration near the terrain in a rice paddy field was measured. An open optical path of 50 m length was employed along with a PbSnTe diode laser. Diurnal change of methane density with 30 seconds temporal resolution was recorded associated with meteorological parameters. A feasibility was proven for a practical application for in situ study of atmospheric methane.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1992-11-25
Volume volume27
Issue issue1
Start Page 45
End Page 53
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307877
JaLCDOI 10.18926/15479
FullText URL Mem_Fac_Eng_OU_24_1_73.pdf
Author Oka, Hisao| Isayama Yoshiharu| Yamamoto, Yoshitake| Yamamoto, Tatsuma|
Abstract There is a small vibration which goes undetected by the naked eyes. It is called a microvibration (MV) or a minor tremor (MT). The MV on the body surface is expected to apply to a clinical examination of the autonomic nervous system. It is not cleared why and how the MV occurs, but there are many papers about its occurrence and clinical application. In this study, MV measuring system, its estimation and basic characteristics are examined. The difference between head MV and thenar MV, individual MV and diurnal and seasonal change are discussed. The power spectrum of MV is obtained using an autoregressive model.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1989-11-29
Volume volume24
Issue issue1
Start Page 73
End Page 80
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307633
JaLCDOI 10.18926/19608
FullText URL Mem_Fac_Eng_OU_33_1_19.pdf
Author Washio, Seiichi| Takahashi, Satoshi| Imoto, Chikashi| Yoshida, Atsumasa|
Abstract 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).
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1998-11-30
Volume volume33
Issue issue1
Start Page 19
End Page 30
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309030
JaLCDOI 10.18926/15500
FullText URL Mem_Fac_Eng_OU_25_2_1.pdf
Author Okada, Hiroyuki| Hida, Moritaka| Sakakibara, Akira| Takemoto, Yoshito|
Abstract Tensile strength and elongation of cast magnesium reinforced with titanium fiber were measured by tensile test. The pull-out test of a titanium rod partially embedded in a magnesium matrix was performed to evaluate interfacial bonding strength between magnesium and titanium. It was found that when the fiber volume fraction was changed from 1% to 14%, the tensile strength was improved with increase of volume fraction, while the improvement of elongation tended to be restrained beyond the volume fraction of 10%. The interfacial strength was revealed to be strong, and this was substantiated by the scanning electron microscopy showing an excellent wettability between the titanium fiber and the magnesium matrix.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 1
End Page 8
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307559
JaLCDOI 10.18926/14119
FullText URL Mem_Fac_Eng_OU_40_1_31.pdf
Author Ogawa, Takafumi| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract We analyze the melting of spherical Yukawa clusters by Monte Carlo simulations. Spherical clusters are expected to be found in dusty plasmas in an isotropic environment such as microgravity and serve as a model for classical clusters. We obtain the specific heat through fluctuations of the potential energy and identify its peak as the transition temperature. Melting temperatures are compared with those of bulk Yukawa systems and it is confirmed that the melting temperature increases and approaches the bulk value with the increase of the system size.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2006-01
Volume volume40
Issue issue1
Start Page 31
End Page 35
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308329
JaLCDOI 10.18926/15443
FullText URL Mem_Fac_Eng_OU_26_2_111.pdf
Author Nara, Shigetoshi| Banzhaf Wolfgag|
Abstract 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.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1992-03-28
Volume volume26
Issue issue2
Start Page 111
End Page 128
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307718
JaLCDOI 10.18926/15517
FullText URL Mem_Fac_Eng_OU_25_2_123.pdf
Author Taniguchi, Takeo| Ohta, Chikashi|
Abstract The aim of this investigation is the proposal of 3D mesh generation method based on the Delaunay triangulation. The method is valid for the finite element modelling of any convex 3D domain into tetrahedra with optimum geometrical configuration. This paper includes the mathematical background of the mesh generation method, its detail, proposal of some efficient tools for faster and more rigorous computations, and some examples of the mesh generation.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 123
End Page 133
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307904
JaLCDOI 10.18926/14081
FullText URL Mem_Fac_Eng_OU_41_1_20.pdf
Author Imamura, Takuji| Konishi, Masami| Imai, Jun|
Abstract In this paper, we propose a simultaneous optimization method for inventory control and production planning problem for a chemical batch plant. The plant consists of blending process, intermediate storage tanks and filling process. In the proposed method, the original problem is decomposed into production planning sub-problem and inventory control sub-problem. Then the decision variables are optimized by alternately solving each sub-problem. The solution of the proposed method is compared with that of centralized optimization method. The effectiveness of the proposed method is investigated from numerical computational results.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2007-01
Volume volume41
Issue issue1
Start Page 20
End Page 30
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308626
JaLCDOI 10.18926/15368
FullText URL Mem_Fac_Eng_OU_35_155.pdf
Author Takahashi Hiromitsu| Munesawa, Yoshiomi| Kajihara, Yasuhiro| Osaki, Hirokazu| Wada Yatarou|
Abstract This paper proposes a concept of a mobile type maintenance robot (MMR in shortly) that is controlled by the tele-operation for assuring the safety and health improvement of work forces. The main components of this system are the industrial robot, an image processing unit, vehicle and computers for tele-operation. Our focus is paid on a method that determine a pathway to move every places where troubles would occur. This method makes it possible that the MMR could arrive any place in the factory with three times of turns at most. Additionally, turning radius of the vehicle is considered for correcting the pathway near the corners to make it possible that it arrives to the place accurately.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 155
End Page 161
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307844