Effects of Die Geometry on Variation of the Deformation Rate in Equal Channel Angular Pressing

한준현,장현준,지광구,오규환 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.3

The deformation behavior within the deformation zone of a workpiece during equal channel angular pressing (ECAP) was investigated using the finite element method. The effects of die geometry on the variations of normal and shear deformations were studied with a deformation rate tensor (D). The zero dilatation line, at which the normal components (D11 and D22) of the deformation rate tensor (D) are zero, in the die coincided with the line of intersection of the two die channels irrespective of die geometry such as curvature angle (Ψ) and oblique angle (Φ), while the maximum shear line, at which the shear components (D12 and D21) of the deformation rate tensor (D) have maximum value, is dependant on the die geometry The deformation behavior within the deformation zone of a workpiece during equal channel angular pressing (ECAP) was investigated using the finite element method. The effects of die geometry on the variations of normal and shear deformations were studied with a deformation rate tensor (D). The zero dilatation line, at which the normal components (D11 and D22) of the deformation rate tensor (D) are zero, in the die coincided with the line of intersection of the two die channels irrespective of die geometry such as curvature angle (Ψ) and oblique angle (Φ), while the maximum shear line, at which the shear components (D12 and D21) of the deformation rate tensor (D) have maximum value, is dependant on the die geometry

영상 분석과 Pan-Tilt 카메라 자동 조정에 의한 실시간 이동물체 추적

한준현,이병선,이은주 한밭대학교 2006 한밭대학교 논문집 Vol.4 No.1

본 논문에서는 실시간 영상 분석과 Pan-Tilt카메라 자동 조정을 통하여 이동물체를 검출하고 추적 하는 시스템을 저l 안한다. 본 시스템은 입력 영상의 정보를 유지하면서 치라할 데이터륜 줄이기 위해 먼저 입력 영상을 그레이 영상으로 변환하고, 소벨 에지 기법에 의하여 에지 영상을 추출한다 그리고 이전 에 지 영상과 현재 에지 영상간의 차영상과 이진변환밀도값을 이용하여 이동 물체의 영역을 걸정한다. 그 후, 현재 영상파 이전 영상에서의 검출된 물제의 무게 중심의 거리를 근거하여, 이동 물제를 추적한다. 그리고 이동 물체의 화면 내 위치에 따라서 카메라의 방향을 자동으로 조정하여 이동 물제를 연속적으로 추적한 다. 제안한 시스템은 Pan-Tilt카메라를 이용하여 실시간으로 이동물체를 검출하고 추적할 수 있음을 보였 다. In this Paper. we propose a surveillance system that detects and tracks moving object using automatic Pan-Tilt camera control and real time image analysis. Proposed system converts source image to gray scale, and extracts edge using Sobel-edge method so that we can reduce the size of data and keep the information of image. And proposed system uses difference image between previous and current edge images, accumulation of binary conversion densify of difference image to specify area of moving area. Then proposcd systcm tracks moving object according to the distance between centroids of previous and current detected objects. And proposed system adjusts the direction of Pan-Tilt camera so that we can track object continuously. As experimcnt rcsults, proposed system can detect and track moving object by real time using Pan-Tilt camera.

EBSD에 의한 A1050 압연판재의 결정립 구조 분석

한준현,신명철,Han, Jun-Hyun,Shin, Myung-Chul 한국분석과학회 2001 분석과학 Vol.14 No.1

압연판재의 결정립 미세화를 위해 새롭게 도입된 극저온 강압연법을 극저온 압연법, 상온 강압연법과 비교 분석하였다. EBSD를 이용하여 결정립 구조를 분석하였으며, 결정립 크기를 측정하였다. 극저온 압연법과 상온 강압연법은 각각 39%와 87%의 결정립 크기 감소효과를 보였으며, 극저온 강압연법은 상온 강압연법과 비슷한 결정립 감소효과를 갖고 있었다. 따라서 강압연법이 극저온 압연법보다 결정립 미세화에 훨씬 더 효과적임을 알 수 있었다. The effect of cryogenic heavy rolling method on grain refinement has been studied and compared with those obtained by previous methods of cryogenic rolling and heavy rolling developed separately. Both grain structure and grain size were analyzed using electron back scattered diffraction (EBSD), which can distinguish grains each other by means of crystallographic misorientations between them. The cryogenic rolling and heavy rolling exhibit reduction in grain size of 39% and 87%, respectively, and the cryogenic heavy rolling shows reduced grain size similar to that observed in the heavy rolling. The heavy rolling was proved more effective in grain size refinement than the cryogenic rolling.

폭발접합에 의해 제조된 AA5083/AA1050/SS41 삼중판재의 전단병형거동

한준현,안재평,오규환,신명철 대한금속·재료학회 2003 대한금속·재료학회지 Vol.41 No.4

탄소나노섬유 표면 구리 무전해 도금에 미치는 분산제와 도금 전처리의 영향

한준현,석현광,이상수,지광구,Han, Jun-Hyun,Seok, Hyun-Kwang,Lee, Sang-Soo,Jee, Kwang-Koo 한국분말야금학회 2009 한국분말재료학회지 (KPMI) Vol.16 No.2

This paper deals with the effects of the surfactant and preplate process (sensitization and activation) on electroless copper plating on carbon nano-fiber (CNF). Ultrasonic irradiation was applied both during dispersion of CNF and during electroless plating containing preplate process. The dispersion of CNF and flatness of the plated copper film were discussed based on the changes in surfactant concentration and preplate process time. It was clearly shown that high concentration of surfactant and long time of preplate process could promote the agglomeration of CNF and uneven copper plating on CNF.

냉간 단조된 5083 알루미늄 합금에서의 집합조직 발달과 소성변형 비

한준현,지광구,오규환 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.6

5083 aluminum alloys were cold-forged to study the possibility of enhancing the formability and reducing the planar anisotropy. Texture evolution during cold forging was discussed with pole figure and orientation distribution function (ODF). The formability and planar anisotropy in forged 5083 aluminum alloys were evaluated in terms of the r-value (plastic strain ratio or Lankford parameter) which was not only calculated from the measured pole figures but also measured in direct by tensile tests. The (110) <uvw> fiber texture was developed during cold forging, by which the 5083 aluminum alloy having high formability and low planar anisotropy could be produced. (Received March 18, 2004)

1050 Al 합금의 구속전단 연속가공 시 집합조직 발달에 미치는 초기 집합조직의 영향

한준현,오규환,신명철,이재철 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.11

Studies on effects of the initial textures prior to equal channel angular pressing(ECAP) on the texture evolution in the 1050 Al alloy sheets, fabricated by the continuous confined strip shearing (C2S2) process, were conducted. The four different specimens having various initial textures, i.e. the cold rolled, the heat treated, the warm rolled, and the as-cast 1050 Al alloy sheets, were prepared using various thermomechanical processes. Effect of the texture evolution due to ECAP on deep drawbility and planar anisotropy was analyzed in terms of the γ-values and the Δγ-values determined based on the measured pole figures. A feasibility for producing the 1050 Al alloy sheets having high deep drawbility and low planar anisotropy was demonstrated.

High adhesive and long-life Cu/PET flexible substrate

한준현,박상진,문명운,윤주일 한국표면공학회 2015 한국표면공학회 학술발표회 초록집 Vol.2015 No.11

실시간 영상 분석을 이용한 실용적 감시 장치 구현

한준현,이은주 한밭대학교 정보통신전문대학원 2005 정보통신전문대학원 논문집 Vol.3 No.1

본 논문에서는 보안 감시를 위한 간편하고 실용적인 감시 장치 구현에 관하여 논한다. 본 장치는 실시간 영상 분석을 이용하여 움직이는 물체의 영역을 검출하고 움직임을 추적한다. 움직이는 물체검출은 에지추출, 움직임 추출, 최대이동영역결정으로 이루어진다. 여기서, 에지추출에서는 입력 영상의 정보를 유지하면서 처리할 데이터를 줄이기 위하여 영상의 그레이 변환과 소벨에지 적용으로 수행되고, 움직임추출은 에지영상에 대한 차영상, 이진화와, 미디언 필터링에 의하여 수행된다. 최대이동영역결정은 검출된 움직임 영역에 대한 이진변환 밀도 누적값에 의하여 수행된다. 이동 물체에 대한 움직임 추적은 결정된 최대이동물체영역의 무게중심 추적으로 수행된다. 실험 결과, 제안한 시스템은 일반 개인용 컴퓨터와 USB 카메라를 사용하여 실시간으로 물체를 검출하고 추적할 수 있었다. In this paper, we discuss the implementation of handy and practical monitoring system for security guard. This system detects and tracks moving object using real time image analysis. Detection of moving is performed by edge extraction, moving detection, and decision of maximum moving area. In edge extraction, we convert source image to gray scale, and extract edge using Sobel-edge method so that we can reduce the size of data and keep the information of image. And we use difference image, binarization and median-filtering to detect moving. Then decision of maximum moving area is specified by using accumulation of binary conversion density. And we track the moving object by tracking the centroid of decided maximum moving area. As experiment results, proposed system can detect and track moving object by real time in USB camera and usual PC.

Development of Magnetic Shape Memory Alloy Thin Films for Bio-actuators (초)

한준현,안현태,지광구,임상호,( Joost J. Vlassak ) 대한금속재료학회 ( 구 대한금속학회 ) 2008 대한금속재료학회 학술대회 개요집 Vol.2008 No.1