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 10.18926/14152
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 10.18926/14150
FullText URL Mem_Fac_Eng_39_1_46.pdf
Author Kadono, Keisuke| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract We present a real-space, polynomial-expansion approach to electron dynamics in nanostructured semiconductors. The Chebyshev expansion method is employed for efficient calculation of timeevolution of single-electron wave function. Details of the formulation are described. The method is applied to the electron transport in nanostructured semiconductors such as Si nanowires. The mean-square displacement and diffusivity of electron in Si chains are obtained as functions of length of the chains. The results show clearly ballistic behavior of electron in the pure Si chain.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2005-01
Volume volume39
Issue issue1
Start Page 46
End Page 51
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308231
JaLCDOI 10.18926/14121
FullText URL Mem_Fac_Eng_OU_40_1_40.pdf
Author Takashi, Miyake| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract The electron system of arbitrary degeneracy can be mapped onto a classical system where electrons of the same spin are assigned an additional interaction and the effect of degeneracy is taken into account through an imaginative temperature. We apply this method to electrons in quantum dots modeled as two-dimensional electron liquid confined in a finite domain by a harmonic potential. We analyze distribution functions by molecular dynamics instead of solving integral equations which are not so useful in the case without translational invariance.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2006-01
Volume volume40
Issue issue1
Start Page 40
End Page 43
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308268
JaLCDOI 10.18926/14120
FullText URL Mem_Fac_Eng_OU_40_1_36.pdf
Author Uchida, Atsushi| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract We present a Stochastic-Difference-Equation (SDE) approach to long time-scale molecular dynamics (MD) simulations, which are required for nanosecond-scale phenomena. In this method, the MD trajectory in a fixed time period is obtained as a stationary solution of an action functional based on an error accumulation of the equation of motion along the path, thus reducing the problem to a boundary-value problem, instead of an initial-value problem in the ordinary MD method. We apply the method to formation processes of Cu thin film via nanocluster deposition onto a substrate. The applicability of the SDE algorithm to the problem and the effects of the choice of SDE parameters on the optimization processes of configuration pathway are examined.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2006-01
Volume volume40
Issue issue1
Start Page 36
End Page 39
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308517
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 10.18926/14061
FullText URL Mem_Fac_Eng_OU_42_56.pdf
Author Miyake Takashi| Totsuji, Chieko| Nakanishi Kenta| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract We analyze the ground state of the two-dimensional quantum system of electrons confined in a parabolic potential with the system size around 100. We map the system onto a classical system on the basis of the classical-map hypernetted-chain (CHNC) method which has been proven to work in the integral-equation-based analyses of uniform unbounded systems and then apply classical numerical simulations. We find that the confined system undergoes the transition to the spin polarized state with the decrease of the average density and the corresponding critical value is as low as rs ∼ 0.3 in terms of the usual rs parameter estimated for the average density. As the ground state for given value of the rs parameter, our data give the critical value for the transition around 20 which is consistent with the known possibility. The advantage of our method is a direct applicability to geometrically complex systems which are difficult to analyze by integral equations. The application to the structure like quantum dots reported here is the first example of such applications.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2008-01
Volume volume42
Issue issue1
Start Page 56
End Page 59
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308633
JaLCDOI 10.18926/14059
FullText URL Mem_Fac_Eng_OU_42_48.pdf
Author Totsuji, Chieko| Miyake Takashi| Nakanishi Kenta| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract Based on the mapping introduced by the classical-map hypernetted-chain (CHNC) method, classical numerical simulations, Monte Carlo and molecular dynamics, have been applied to the twodimensional electron fluid and the results are compared with those of quantum Monte Carlo simulations hitherto reported. It is shown that polarization properties of the ground state obtained by the diffusion Monte Carlo method are reproduced within the accuracy of quantum simulations by both of two mapping functions for the quantum temperature which have been proposed within the CHNC method. These results may serve as the basis of numerical simulations based on the CHNC method which are applicable to finite non-periodic systems like quantum dots and systems at finite temperatures.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2008-01
Volume volume42
Issue issue1
Start Page 48
End Page 52
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308425
JaLCDOI 10.18926/14058
FullText URL Mem_Fac_Eng_OU_42_44.pdf
Author Ogawa Takafumi| Tsuruta, Kenji| Totsuji, Chieko| Totsuji, Hiroo| Hiroshi Iyetomi|
Abstract To analyze vibrational properties of Si crystal with a single charge-neutral vacancy, we perform large-scale simulations based on tight-binding molecular-dynamics method. Vibrational modes and frequencies are obtained by diagonalizing dynamical matrix within a harmonic approximation. Results indicate that there exist vibrational modes spatially localized around the vacancy and large frequency shifts associated with the localized modes contribute significantly to reduction of the vibrational free energy.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2008-01
Volume volume42
Issue issue1
Start Page 44
End Page 47
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308412
JaLCDOI 10.18926/17822
FullText URL Mem_Fac_Eng_OU_43_1.pdf
Author Shimizu, Kenichi| Torii, Tashiyuki| Ishida, Koki|
Abstract Using a fatigue testing method by which fatigue cracks can be initiated and propagated in a film adhered to cover an elliptical through-hole in a base plate subjected to push-pull cyclic loads, annealed copper films with the thickness of 100μm and those reduced the thickness from the 100μm to 50μm by an electro-polishing were fatigued under a constant stress amplitude with a stress ratio of zero. The crystal rotation behavior with the fatigue crack propagation was investigated by measuring the crystal orientation around the fatigue crack initiated from the notch root before and after fatigue testing, using EBSD (Electron Back-scatter Diffraction) method. Then, the change of crystal orientation with fatigue testing was evaluated quantitatively from the misorientation between the crystal orientation matrix on the same point obtained before and after fatigue testing. As a result, the angle of the crystal rotation obtained from the region showing the high fatigue crack propagation rate was larger than that obtained from the region showing the low fatigue crack propagation rate for the film with the thickness of 100μm, while the fatigue crack propagated faster in the film with the thickness of 50μm than that with the thickness of 100μm regardless of the small crystal rotation angles with the fatigue testing for the film with the thickness of 50μm.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 1
End Page 7
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308710
JaLCDOI 10.18926/14096
FullText URL Mem_Fac_Eng_OU_40_1_1.pdf
Author Ma, YouLi| Shimizu, Kenichi| Torii, Tashiyuki|
Abstract A testing for bent fatigue crack propagation under mixed-mode conditions was carried out using fatigue and annealed slant precracks with different slant angles, β ,defined as the angle between loading and precrack directions in a rectangular plate. As a result, bent fatigue crack from the fatigue precrack with β =45deg. propagated under mixed-mode conditions with mode II stress intensity factor (K(II))(est) evaluated from the discontinuous displacement measured along the crack. On the other hand, bent fatigue crack from the fatigue precrack with β =60deg. and from the annealed precracks with both slant angles of β =60deg. and β =45deg. propagated under the mode I behavior. This was because the compressive residual stress near the fatigue precrack caused contact to each other between the upper and the lower surfaces of the precrack with the smaller slant angle β . Furthermore, the fatigue crack propagation rates indicated almost the same relationship for all the data, using the mixed-mode effective stress intensity factor (K(M))(est), calculated from the discontinuous displacement measured along the bent fatigue crack.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2006-01
Volume volume40
Issue issue1
Start Page 1
End Page 8
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308402
JaLCDOI 10.18926/14069
FullText URL Mem_Fac_Eng_OU_42_104.pdf
Author Donghui, MA| Torii, Tashiyuki| Shimizu, Kenichi| Matsuba, Akira|
Abstract As model specimens of surface film-bonded materials, pure copper films with a thickness of 100μm were bonded to the surface of steel base with epoxy resin, where the tensile residual stress was measured by an X-ray on the surface copper film. The distribution of initial electric resistance was measured on both copper film and base specimen by a direct current potential drop technique. As a result, there was a good agreement between the measured and theoretical values. From the fatigue testing results, it was shown that the measured electric resistance increased with the fatigue crack length on the copper film, which was almost equal to the theoretical value calculated for a central slit in a plate with finite width. This was probably because the fatigue crack was opened due to the tensile residual stress on the film even under unloading condition. In addition, the internal crack length during fatigue was examined by ultrasonic testing for the film-bonded specimen. As a result, there was a difference in the fatigue crack length between the surface copper film and the inner base.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2008-01
Volume volume42
Issue issue1
Start Page 104
End Page 109
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308537
JaLCDOI 10.18926/14088
FullText URL Mem_Fac_Eng_OU_41_1_93.pdf
Author Tarequl Islam Bhuiyan| Nakanishi, Makoto| Fujii, Tatsuo| Takada, Jun|
Abstract Co-precipitation method has been employed to fabricate neodymium substituted hematite with different compositions from the aqueous solution of their corresponding metal salts. Thermal analysis and X-ray diffraction studies revealed the coexistence of Fe(2)O(3) and Nd(2)O(3) phases up to 1050℃ and formation of solid solution phase among them at 1100℃ and above temperatures, which was evidenced by shifting of the XRD peaks. Unit cell parameters and the cell volumes of the samples were found to increase by adding Nd(3+) ions in the reaction process. FESEM studies showed the suppression of particle growth due to the presence of Nd(3+) ions. Spectroscopic measurement evidenced that neodymium substituted hematite exhibited brighter yellowish red color tone than that of pure α-Fe(2)O(3).
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2007-01
Volume volume41
Issue issue1
Start Page 93
End Page 98
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308163
JaLCDOI 10.18926/19624
FullText URL Mem_Fac_Eng_OU_31_1_11.pdf
Author Zhang Chunxiao| Tanigawa Satoshi| Uchida, Tetsuya| Shimamura, Kaoru|
Abstract Poly[(benzo[1,2-d:5,4-d']bissthiazole-2,6-diyl)-1,4-phenylene](cis-PBZT)with a relatively high molecular weight was prepared by a new synthesis route. Properties of the synthesized polymer, such as thermostability, liquid crystallinity etc. were investigated and compared with those of trans-PBZT. cis-PBZT was crystallized from dilute solution and the electron microscopy showed that the precipitate was a rod-like crystal similar to that of trans form. In spite of rigid nature of the back bone, cis-PBZT showed poor crystallinity.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1996-12-27
Volume volume31
Issue issue1
Start Page 11
End Page 17
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309203
JaLCDOI 10.18926/19622
FullText URL Mem_Fac_Eng_OU_31_1_5.pdf
Author Shimamura, Kaoru| Zhang Chunxiao| Uchida, Tetsuya|
Abstract Rigid polymer poly(p-phenylene benzobisthiazole) was crystallized from dilute solution. Electron microscopy showed that upon quenching, flat fibrils with several nm thick were produced. Subsequent heat treatment in solvent changed the fibril into "shish-kebab". On the other hand, by isothermal crystallization, an aggregate of parallel rod-like crystals was obtained. The molecular chains were accommodated normal to the rod. Based on the observation of crystal morphology, the isothermal crystallization mechanism was proposed. Because of regidity of polymer chains and wide distribution of the molecular length, the chain ends were inevitably included within the crystals resulting in crystal defects such as axial shift, lattice curvature and edge dislocation which were directly observed by lattice imaging.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1996-12-27
Volume volume31
Issue issue1
Start Page 5
End Page 10
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309167
JaLCDOI 10.18926/15352
FullText URL Mem_Fac_Eng_OU_35_35.pdf
Author Shimamura, Kaoru| Uchida, Tetsuya| Inoue, Tomohiro|
Abstract Rigid polymer, poly(p-phenylene benzobisthiazole), formed lamellar crystals where the molecular chains were oriented perpendicular to the lamellae. It was supposed that, because of wide distribution in the chain length, the lamellar surface bristled with the chain cilia among which many voids were included. Crystallographically, this region afforded us a transitional structure from full to deficient packings of chains. The structure was analyzed using the scanning probe microscope. In the course the method for imaging one molecular chain end was developed. From the images it was concluded that an isolated long cilius did not move so violently at room temperature.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 35
End Page 40
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307784
JaLCDOI 10.18926/15350
FullText URL Mem_Fac_Eng_OU_35_29.pdf
Author Shimamura, Kaoru| Munesawa Yuhji| Uchida, Tetsuya|
Abstract Poly (ethylene-block-vinyl alcohol), which consisted of both hydrophobic and hydrophilic blocks, was prepared by using polyethylene single crystals as starting material. Polyethylene single crystals reacted with fuming nitric acid resulting in long methylene chains with functional groups such as COOH and NO(2) at the ends (the chain length were almost same as the lamellar thickness of polyethylene single crystal). The functionalized methylene chains were allowed to react with 4-aminostyrene to give corresponding amides, i.e., methylene chains with vinyl groups at the ends (macromer). The macromers were extended by block-copolymerization with vinyl acetate, then saponified resulting in PE/PVA block co-polymer. The block copolymer was molded into sheets which were subsequently heat-treated in contact with hydrophilic or hydrophobic media. Depending on the media, the sheet surface changed at high temperature reversibly from hydrophilic to hydrophobic and vice versa. The surface property was fixed by quenching because both blocks were able to crystallize. Thus the surface of this material can be tailored for various purposes at high temperature, and then used in stable at room temperature.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 29
End Page 34
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307155
JaLCDOI 10.18926/14136
FullText URL Mem_Fac_Eng_39_1_16.pdf
Author Uchida, Tetsuya| Ishimaru, Sanae| Shimamura, Kaoru| Uji, Akihito| Matsuo, Toshihiko| Ohtsuki, Hiroshi|
Abstract PE film was treated with fuming nitric acid at 80℃ for 20 min, resulting in introduction of COOH moieties on the film surface. The COOH’s were reacted with ethylenediamine, whose amino groups were used for linking with (2-[4-(dibutylamino)phenyl]ethenyl)-3-carboxy-methylbenzo-thiazolium, photoelectric dye (NK-5962), which absorbs visible light and converts the photon energy to electric potentials. The dye molecules were immobilized on the PE film surface and they were able to stimulate chick retinal tissues on incidence of visible light. These facts hopefully lead to development of an artificial retinal prosthesis.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2005-01
Volume volume39
Issue issue1
Start Page 16
End Page 20
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308066
JaLCDOI 10.18926/19692
FullText URL Mem_Fac_Eng_OU_33_2_111.pdf
Author Fujihara Yutaka| Munesawa, Yoshiomi| Osaki, Hirokazu|
Abstract Our country faces a serious problem of the environmental pollution by the production and the large quantity consumption of the industry product. The thoroughness of resources recycling has become necessary to solve these problems. As for the product design and the production control, how productivity should be improved has been discussed with extreme emphasis. But from now, as for the product design, both assemblability and disassemblability must be taken into consideration at the same time. And also in production management, it must be investigated how the products can be recycled in the low cost. Therfore, the facility layout method with two phases in recycling plant, which is composed of both the procedure for the layout of facility group and the procedure for the layout of intermal facility group by the optimal solution method and the suboptimal solution method by neural network is proposed in this paper.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1999-04-27
Volume volume33
Issue issue2
Start Page 111
End Page 119
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309035
JaLCDOI 10.18926/19682
FullText URL Mem_Fac_Eng_OU_33_2_91.pdf
Author Munesawa, Yoshiomi| Osaki, Hirokazu| Kajihara, Yasuhiro|
Abstract In this paper, we propose the method to determine the position of the 2 cameras for the multiviewpoints as the robot is the work place. The optical axit's direction of the 1st camera is determined in the base ot work contents in teleoperation. The multiviewpoints system uses the 2 camera units that aren't installed side by side, so that the direction of the 2nd camera is decided in the base of the angle between the optical axes' direction of 2 cameras. Next, the distance from the camera to the work place is determined according to the distance resolution of image on the monitor, and the camera type of which the point-blank range is not this distance is selected. And the efficacy ot this system is examined with an experiment.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1999-04-27
Volume volume33
Issue issue2
Start Page 91
End Page 96
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309052