JaLCDOI 10.18926/15357
フルテキストURL Mem_Fac_Eng_OU_35_53.pdf
著者 Kim Tae Yong| 加川 幸雄|
抄録 Fresnel zone plate lens (FZPL) has widely been used in electromagnetic antenna applications. Most analysis method based on the potential (scalar) wave approximation has been applied to a few very limited and simplified cases. The present paper analyzes the FZPL in more general form including the diffraction and transmission using the method of moments (MoM). The focusing gain characteristics in the oblique incidence as well as in the normal incidence are considered. The MoM solution using the three-dimensional vectorial formulation requires a large memory space for the FZPL as it is operated at a short wavelength. This is simply overcome by using an iterative conjugate gradient method for the numerical evaluation. The MoM solutions are compared with the other solutions.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2001-03-27
35巻
1-2号
開始ページ 53
終了ページ 61
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307849
JaLCDOI 10.18926/15477
フルテキストURL Mem_Fac_Eng_OU_23_2_33.pdf
著者 Ishihara Yuji| 山本 恭二|
抄録 This paper deals with the low Mach numbers flow of a rarefied vapour past a liquid sphere accompanied with condensation and evaporation at its surface. The linearized Bhatnager-Gross-Krook(B-G-K} equation is used for the analysis, and from it the integral equations of the density, temperature and flow velocities are derived. These integral equations are solved numerically over a wide range of the Knudsen number covering from the slip flow to the nearly free molecular flow. The drag on the sphere is also calculated and is compared with that of previous work.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1989-03-30
23巻
2号
開始ページ 33
終了ページ 44
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307401
JaLCDOI 10.18926/15374
フルテキストURL Mem_Fac_Eng_OU_30_1_35.pdf
著者 Mahmood Zaheed| 加川 幸雄|
抄録 Divergence-free shape functions are proposed for the finite elements, with which inhomogeneously-loaded and arbitrarily-shaped waveguides are analysed. The method is based on vectorial finite element formulation employing edge elements. The shape functions used for the approximation of the fields are shown analytically to be divergence-free and as an evidence, the non-physical solutions that appeared in the longitudinal component finite element formulation have been shown to be absent. To show the validity of the elements, application is made for the analysis of rectangular waveguides loaded with dielectric slab and a waveguide with curved structure. The solutions obtained are compared with the analytical ones or the solutions reported elsewhere. The degree of accuracy has been found satisfactory.
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 35
終了ページ 46
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307293
JaLCDOI 10.18926/15379
フルテキストURL Mem_Fac_Eng_OU_30_1_63.pdf
著者 Koshimoto Marcos| Mahmood Zaheed| 加川 幸雄|
抄録 Optical fibers or integrated optical waveguides have arbitrary cross-sectional index or refraction distribution. An efficient finite element method for analyzing the propagation characteristics of dielectric / optical waveguides with open boundary is presented. The propagation modes are hybrid, for which a variational expression is formulated in terms of the longitudinal electric and magnetic field components. Infinite elements are introduced to consider open boundary or to extend the region to infinity. Several specific examples are given and the results are compared with those obtained by other approximate methods. Very close agreements have been found.
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 63
終了ページ 73
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307545
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 10.18926/15493
フルテキストURL Mem_Fac_Eng_OU_24_2_17.pdf
著者 小西 忠孝| 馬場 充|
抄録 Pressure distribution has been measured and analyzed to clarify the fundamental characteristics of "continuous oil-film" formed in a transparent journal bearing, into which oil in general use is supplied. Measured pressure mostly shows quasi-Sommerfeld distribution, which is characterized by downstream shift of pressure profile and underdevelopment of pressure trough compared with Sommerfeld distribution for perfect oil-film. Sommerfeld distribution is approximately observed only under limited conditions : low eccentricity and low speed. Quasi-Sommerfeld state is rather common in "continuous oil-film", unruptured film formed by using practical lubricants, than Sommerfeld state. Continuous oil-film is accompanied by fine bubbles and is controlled by the growing up or down of the bubbles.
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 17
終了ページ 30
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307431
JaLCDOI 10.18926/46948
フルテキストURL mfe_38_1-2_015_027.pdf
著者 Torigoe, Takashi| Konishi, Masami| Imai, Jun| Nishi, Tatsushi|
抄録 In these days, mechanical systems are becoming more complex and highly automated. So, there exist wide variety of demands for reliable diagnostic technology. A reliable data analysis and quantitative diagnosis method of mechanical system is necessary for the purpose. In this paper a quantitative diagnosis method for looper height control system has been developed based on neural network technologies. The wavelet transformation is used for pre-processing to analyze characteristics of looper height control system. And, self organizing map neural network is used for the purpose of classification based on the pre-processed data. After that, the classified results are used for quantitative diagnosis in hierarchical neural network.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2004-03
38巻
1-2号
開始ページ 15
終了ページ 27
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 80016785934
JaLCDOI 10.18926/15506
フルテキストURL Mem_Fac_Eng_OU_25_2_17.pdf
著者 榊原 精| Kanadani, Teruto| Kaneeda, Toshiaki| Hosokawa, Norio|
抄録 Effect of the soft surface layer that was formed on low temperature aging of Al-Zn alloy on fatigue strength was studied under repeated tensile loading. Vickers microhardness test revealed that there existed less hardened region in the vicinity of grain boundary and surface, and that the region extends 50 to 100μm from the surface inward. From the plot of the stress amplitude against the number of cycles to failure, it is concluded that the presence of less hardened surface layer strengthens fatigue resistance of the age hardened Al-Zn alloys containing 8 to 16mass % Zn under the repeated tensile loading.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1991-03-28
25巻
2号
開始ページ 17
終了ページ 23
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307685
JaLCDOI 10.18926/14069
フルテキストURL Mem_Fac_Eng_OU_42_104.pdf
著者 Donghui, MA| Torii, Tashiyuki| Shimizu, Kenichi| Matsuba, Akira|
抄録 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.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2008-01
42巻
1号
開始ページ 104
終了ページ 109
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002308537
JaLCDOI 10.18926/14096
フルテキストURL Mem_Fac_Eng_OU_40_1_1.pdf
著者 馬 有理| 清水 憲一| 鳥居 太始之|
抄録 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.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2006-01
40巻
1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 120002308402
JaLCDOI 10.18926/14057
フルテキストURL Mem_Fac_Eng_OU_42_36.pdf
著者 Kato, Hidehiro| Nekado, Kenta| Nogami, Yasuyuki| Morikawa, Yoshitaka|
抄録 This paper proposes an exponentiation method with Frobenius mappings. Our method is closely related to so-called interleaving exponentiation. Different from the interleaving exponentiation methods, our method can carry out several exponentiations using same base at the same time. The efficiency to use Frobenius mappings for an exponentiation in extension field is well introduced by Avanzi and Mihailescu. This exponentiation method is based on so-called simultaneous exponentiation and uses many Frobenius mappings. Their method more decreased the number of multiplications; however, the number of Frobenius mappings inversely increased. Compared to their method , the number of multiplications needed for the proposed method becomes about 20% larger; however, that of Frobenius mappings becomes small enough.
キーワード exponentiation Frobenius mapping extension field
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2008-01
42巻
1号
開始ページ 36
終了ページ 43
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002308105
JaLCDOI 10.18926/15354
フルテキストURL Mem_Fac_Eng_OU_34_1.pdf
著者 Song Baoyin| 稲葉 英男| 堀部 明彦| Takahashi Takashi|
抄録 The experiment for investigating the falling snow melting characteristics of warm water flowing along sheet channels spread on a roof was performed in Tookamachi city, Nigata prefecture from February 6 to February 7, 1995. The sheet surface temperatures at 11 positions in 3 channels were measured. A physical model for a gas-water-snow system was constructed to compare the predicted results with the measured ones. A fully spread uniform water film in the sheet channel was observed in the experiments. The experimental results elucidated that it was feasible to use warm water flowing along sheet channels for melting falling snow on roofs. The temperature drop in the sheet channel mainly depended on the snowfall intensity, atmospheric temperature and wind speed. Under the influence of the roof edge, the temperature drop in the channel next to the side edge was much larger than that in middle channels. A water-snow two phase flow or a snow covered frozen water was experienced temporarily in the lower reaches of the water flowing channel. These suggest that a larger water flow rate is needed for the channel next to the roof edge, and a higher inlet temperature or a greater water flow rate is required for a severe weather condition. There was reasonably good agreement between the measured and predicted water temperatures.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2000-03-27
34巻
1-2号
開始ページ 1
終了ページ 12
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307686
JaLCDOI 10.18926/46953
フルテキストURL mfe_38_1-2_061_071.pdf
著者 Kanatani, Kenichi| Sugaya, Yasuyuki|
抄録 The Tomasi-Kanade factorization for reconstructing the 3-D shape of the feature points tracked through a video stream is widely regarded as based on factorization of a matrix by SVD (singular value decomposition). This paper points out that the core principle is the affine camera approximation to the imaging geometry and that SVD is merely one means of numerical computation. We first describe the geometric structure of the problem and then give a complete programming scheme for 3-D reconstruction.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2004-03
38巻
1-2号
開始ページ 61
終了ページ 71
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 80016889443
JaLCDOI 10.18926/19618
フルテキストURL Mem_Fac_Eng_OU_33_1_59.pdf
著者 Fujihara Yutaka| 大崎 紘一|
抄録 In this paper, we propose a method to solve simultaneously facility layout problem and scheduling problem. About a initial random layout planning, the production scheduling and the transportation scheduling of AGV are obtained by using priority rules. From the obtained transportation scheduling, the critical transportation and the closeness rating are obtained. Facility layout is renewed by the combined procedure of genetic algorithm and tabu search in order to reduce the material handling cost. By using this renewed facility layout, the production scheduling and the transportation scheduling of AGV are also revised until no further improvement is possible.
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 59
終了ページ 64
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002308989
JaLCDOI 10.18926/15412
フルテキストURL Mem_Fac_Eng_OU_26_1_21.pdf
著者 野津 滋| 稲葉 英男|
抄録 A numerical study is performed for the facilitated diffusion of carbon-dioxide in an ultrapure water film flowing downward along a vertical surface. The model adopted for the present work includes the effects of the reaction rate for the hydration of CO(2)in a liquid. Comparison of the total concentration of CO(2) for different film thickness indicates that the effects of the hydration is more remarkable for the thinner liquid film.
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 21
終了ページ 26
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307958
JaLCDOI 10.18926/17829
フルテキストURL Mem_Fac_Eng_OU_43_16.pdf
著者 Kurose Tomoyuki| 鶴田 健二| 東辻 千枝子| 東辻 浩夫|
抄録 The finite-difference time-domain (FDTD) method has been applied to the calculation of the phonon band structure of two-dimensional (2D) phononic crystals, consisting of metal cylinders placed periodically in liquid. By comparing several combinations of materials for metal cylinder and liquid, we analyze the dependence of the band structures on sound speed and density of liquid media. Moreover, the negative refraction of the acoustic waves is observed at the interfaces between phononic crystal slab and the liquid. We find that an acoustic“lens effect”with the slab appears due to the negative refractions. The relationship between the focal intensity in the lens effect and the band structure is discussed.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2009-01
43巻
開始ページ 16
終了ページ 21
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002308928
JaLCDOI 10.18926/19953
フルテキストURL Mem_Fac_Eng_OU_44_1.pdf
著者 Nagai Shinji| Umeda Ryosuke| 鶴田 健二|
抄録 In this paper, we investigate a light-confinement phenomenon in the structure which has triangular latice composed of Double NeGative Metamaterial (DNGM). In geometrical optics consideration, this structure is expected to confine lights completely by sequential refractions in the structure. We demonstrate it by using the two dimensional finite-difference time-domain simulations. We introduce Drude-Lorentz model for dielectric and magnetic dispersion of the material at optical frequencies. We analyze quantitatively the effects of energy loss in the DNGM on the light-confinement efficiency.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2010-01
44巻
開始ページ 1
終了ページ 6
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002309117
JaLCDOI 10.18926/14153
フルテキストURL Mem_Fac_Eng_39_1_56.pdf
著者 菅谷 保之| 金谷 健一|
抄録 We present a new method for extracting objects moving independently of the background from a video sequence taken by a moving camera. We first extract and track feature points through the sequence and select the trajectories of background points by exploiting geometric constraints based on the affine camera model. Then, we generate a panoramic image of the background and compare it with the individual frames. We describe our image processing and thresholding techniques.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2005-01
39巻
1号
開始ページ 56
終了ページ 62
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002308594
JaLCDOI 10.18926/17851
フルテキストURL Mem_Fac_Eng_OU_43_108.pdf
著者 Nekado, Kenta| Kato, Hidehiro| Nogami, Yasuyuki| Morikawa, Yoshitaka|
抄録 Recently, pairing-based cryptographies such as ID-based cryptography and group signature have been studied. For fast pairing calculation, not only pairing algorithms but also arithmetic operations in extension field must be efficiently carried out. The authors show efficient arithmetic operations of extension field for Xate pairing especially with Freeman curve.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2009-01
43巻
開始ページ 108
終了ページ 112
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002308904
JaLCDOI 10.18926/15414
フルテキストURL Mem_Fac_Eng_OU_26_1_27.pdf
著者 冨田 栄二| Nsunge Felix Chintu| 浜本 嘉輔|
抄録 Distributions of hydrogen gas concentration in a suddenly started, single shot hydrogen gas jet issuing from a 1 mm diameter injector into still air were measured using laser interferometry method. This unsteady, turbulent free jet flow has also been calculated using the two-equation, high Reynolds number version of k-ε turbulence model and hybrid scheme for treating combined diffusion and convection in the SIMPLE algorithm. The injection pressure was 0.5 MPa for which predicted and measured temporal jet tip penetration distributions indicate that the jet discharged into still air at Mach 0.25. The level of agreement between present prediction and measurement is good in some regions and poor in others.
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 27
終了ページ 41
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307648