• Title/Summary/Keyword: Interface technique

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Computational Study on the Characteristics of Nonlinear Wave Caused by Breaking Waves of Two-Dimensional Regular Periodic Wave (2차원 진행규칙파열에서의 쇄파현상에 따른 비선형성 파의 특성에 관한 수치적 연구)

  • 박종천;관전수명
    • Journal of Ocean Engineering and Technology
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    • v.10 no.3
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    • pp.50-61
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    • 1996
  • The breaking phenomenon of regular periodic waves generated by a numerical wave maker is simulated by finite-difference method which can cope with strong interface motions. The air and water flows are simultaneously solved in the time-marching solution procedure for the Navier-Stokes equation. A density-function technique is devised for the implemenation of the interface conditions. The accuracy is examined and applied to the simulation of two-dimensional breaking phenomena of periodic gravity waves.

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Characteristics of Welded Zone Using Solar Energy Concentration (태양광선을 이용한 용접부 특성)

  • Prasad, K.D.V.;Kim, I.S.;Sung, B.S.;Kim, B.C.
    • Journal of the Korean Solar Energy Society
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    • v.21 no.2
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    • pp.9-17
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    • 2001
  • In this paper the attempts made by the authors to explore the feasibility of utilising concentrated solar beam radiation for joining engineering thermoplastics such as Acrylonitrilc/Butadiene/Styrene (ABS), Polycarbonate(PC) and Polymethylmethacrylate(PMMA) are presented. In addition, to study the joining of the materials, necessary experimentation with applying primer was performed. Tensile tests were conducted to determine the bond strength achieved at the specimen joint interface. Microscopic examinations of the fractured joints were performed in order to analyse the overall bond quality. Finally, the results in terms of bond strength achieved at the joint interface and energy consumed in the process were compared with those obtained with similar thermoplastic joining technique utilising microwave energy. In conclusion some advantages and limitations were outlined and necessary improvements of the jointing technique were recommended.

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Scattering of Surface Waves in Anisotropic Media for Applications in Wave Barriers and Non-Destructive Evaluation (방진구조물 및 비파괴 응력파 탐상의 응용을 위한 비등방성 재료의 표면파 산란에 관한 연구)

  • 이종세
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.2
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    • pp.77-85
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    • 1998
  • Propagation of elastic surface waves in anisotropic media is considered in this study. An analytical technique is proposed to study the scattering of surface waves at the interface between two anisotropic quarter-spaces. The Green's function technique is used to derive a system of equations which can determine the scattering coefficients at the interface. A numerical study is carried out and the trade-offs between the material anisotropy and inhomogeneity are studied.

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Effect of rapid thermal annealing on interface trap density by using subthreshold slope technique in the FD SOI MOSFETs (완전 결핍 SOI MOSFET의 계면 트랩 밀도에 대한 급속 열처리 효과)

  • Jihun Oh;Cho, Won-ju;Yang, Jong-Heon;Kiju Im;Baek, In-Bok;Ahn, Chang-Geun;Lee, Seongjae
    • Proceedings of the IEEK Conference
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    • 2003.07b
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    • pp.711-714
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    • 2003
  • In this presentation, we investigated the abnormal subthreshold slope of the FD SOI MOSFETs upon the rapid thermal annealing. Based on subthreshold technique and C-V measurement, we deduced that the hump of the subthreshold slope comes from the abnormal D$_{it}$ distribution after RTA. The local kink in the interface trap density distribution by RTA drastically degrades the subthreshold characteristics and mini hump can be eliminated by S-PGA.A.

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THERMAL MODELING TECHNIQUE FOR A SATELLITE IMAGER (인공위성 영상기의 열모델링 방법)

  • Kim, Jung-Hoon;Jun, Hyoung-Yoll;Yu, Myoung-Jong;Kim, Byoung-Soo
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.174-180
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    • 2010
  • Conductive and radiative thermal model configurations of an imager of a geostationary satellite are presented. A two-plane method is introduced for three dimensional conductive coupling which is not able to be treated by thin shell plate thermal modeling technique. Especially the two-plane method is applied to massive matters and PIP(Payload Interface Plate) in the imager model. Some massive matters in the thermal model are modified by adequate correction factors or equivalent thickness in order to obtain the numerical results of thermal modeling to be consistent with the analytic model. More detailed nodal breakdown is specially employed to the object which has the rapid temperature gradient expected by a rule of thumb. This detailed thermal model of the imager is supposed to be used for detailed analyses and test predictions, and be correlated with the thermal vacuum test results before final in-flight predictions.

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Design Technique of Steel Structures using Practical Nonlinear Inelastic Analysis (실용적인 비선형 비탄성해석을 이용한 강구조 설계기술)

  • Kim Seung-Eock;Lee Dong-Ho;Jang Eun-Seok
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.971-976
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    • 2006
  • This paper presents a design technique of steel structures subjected to static and dynamic loadings using practical nonlinear inelastic analysis software. The beam-column approach using the stability functions and the plastic hinge concept enables the software to suitably predict second-order effects and inelastic behavior of beam-columns. For dynamic analysis. the incremental from of the equation of motion is solved by the use of a step-by-step numerical integration procedure in which the assumption of constant acceleration over a small time step is employed. The accuracy of the analysis program is validated using the results of ABAQUS program and experimental tests. A user-friendly graphic interface of the software is developed to facilitate the modeling process and result interpretation of the problem. A design example of large span bridge is presented to detail the direct design process using the practical advanced analysis software.

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The Real-Time Control Technique Over the Environment of Windows Using Virtual Machine Driver (가상머신 드라이브를 이용한 윈도우즈 환경에서의 실시간 제어기법)

  • Chang, Sung-ouk;Lee, Jin-Kul
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.1
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    • pp.1-4
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    • 2002
  • We studied the technique which can control the real system without additional hardware drivers using virtual machine driver operated on the windows operating system. We showed the feasibility of the proposed scheme under the error and the delay of a sampling time on the multi task processing through the load test of the experiment using graphic user interface.

Development of an Automatic Two-Dimensional Mesh Generator using an Inward Offset Boundary Technique

  • Choi, Jin-Woo;Kim, Yohng-Jo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.4
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    • pp.61-66
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    • 2003
  • An excellent mesh construction is of Importance in yielding good results of finite element analysis. The new mesh generation algorithm, which offsets boundaries inward, was developed on the basis of a looping method. An user interface technique and automatic splitting lines which both divide a given domain into subdomains manually or automatically, were used. In addition, the separation method has advantages to prevent the large scale of element size and to control numbers of nodes and elements. This new mesh generation algorithm was proved in practice.

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Hydroxyapatite Precipitation Phenomena on Micro-pore Formed Ti-Nb Alloy by PEO technique

  • Kim, Jeong-Jae;Choe, Han-Cheol
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.11a
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    • pp.137-137
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    • 2015
  • The purposed of this work was to observe hydroxyapatite precipitation phenomena on micro-pore formed Ti-Nb alloy by PEO technique. The Ti-30Nb and Ti-30Ta alloys were remelted at least ten times in order to avoid inhomogeneity, and then cylindrical specimens (diameter 10 mm, thickness 4 mm) were cut by using laser from cast ingots of the Ti alloys. Heat treatment was carried out at $1050^{\circ}C$ for 2 h for homogenization in argon atmosphere. The morphologic change of the alloys were examined by X-ray diffractometer (XRD) and field emission scanning electron microscopy (FE-SEM).

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New Trends in GaAs Epitaxial Techniques (GaAs 에피 성장 기술의 최근 연구 동향)

  • Park, Seong-Ju;Cho, Keong-Ik
    • Electronics and Telecommunications Trends
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    • v.3 no.4
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    • pp.3-12
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    • 1988
  • Epilayer growing process has been recognized as a key technology for successful GaAs based devices and integrations. These may include HEMT, multiple quantum well structures, band gap engineering, and quantum confinement heterostructures. The fabrication of epilayers in these devices must meet very stringent requirements in terms of crystallinity, composition, film thickness and interface quality. In particular, the quality of interfaces is getting more important because the film thickness, and flatness, roughness and stability at interface of ultrathin films cause critical effects on the device performance. This article reviews the current status of modern epitaxial techniques which have been developed in the last few years. First, the new techniques PLE, GI, MEE, TSL based on MBE technique will be reviewed and their technical importance will be stressed. Secondly, MOMBE, GSMBE, CBE which combine the advantages of MBE and MOCVD will also be discussed. Thirdly, the new sophisticated epitaxial technique, ALE, of which mechanism is totally different from others, will also be reviewed. Finally, areas which should be exploited more extensively to accomplish these techniques will be addressed.