• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1535-1537
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• 2009

High performance resistive type touch panel was fabricated on flexible polyethylene terephthalate (PET) substrates coated with Al- and Ga-codoped ZnO (AGZO) films. The AGZO films were deposited by roll-to-roll direct current magnetron sputter at room temperature. The AGZO thin films on PET substrates showed high transparency (> 85 % at 550 nm) and low sheet resistance (450 ${\Omega}$/sq.). These values were similar to those of commercial ITO films used for resistive type touch panel.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.213-213
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• 2010

We investigated the RF sputtering conditions for the deposition of AZO (Al doped ZnO) transparent conducting film on PET using the roll to roll vacuum coater. AZO thin films, sputtered at the various RF powers and working pressures, were studied for their structural, electrical and optical properties.. From the X-Ray diffraction patterns, we calculated the lattice stress using the Bragg equation. The compressive stress tends to decrease with the increase in film thickness. AZO thin film with the thickness of 152nm (1400W, 0.4Pa) exhibit the resistivity of $3.92*10-3{\Omega}/cm$ and the transmittance of 96.9% at 550nm.

• 한국해양공학회지
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• 제37권1호
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• pp.1-7
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• 2023

The motion of small fishing vessels is significantly affected by small waves, leading to accidents, such as capsizing or sinking. This paper presents the results of two types of basin tests. The first test analyzed the characteristics of roll and pitch motions among regular waves with the same wave steepness using the drifting state of three (3G/T, 7G/T, 10G/T) small fishing vessels. The second test analyzed the motion characteristics of the 7G/T fishing vessel under different wave steepness. The first test showed that heave and roll motions are significant in the beam sea, while pitch motion is significant in the bow and stern seas. The second test shows that wave steepness has a linear relationship with roll and pitch motions in the bow and stern seas.

• 융합신호처리학회논문지
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• 제4권2호
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• pp.53-60
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• 2003

무게중심이 높은 차량은 코너링 시에 전복되는 위험을 방지하기 위해 서스펜션 롤 강성이 매우 커야 한다. 어떤 경우에는 효과적인 롤 강성이 주로 타이어 컴플라이언스에 의해 결정되는데, 그러한 경우에는 히브(heave) 진동의 감쇠를 위해 사용되는 쇽업쇼바는 롤 진동을 억제하는 데에는 별다른 효과가 없다. 따라서, 차량의 측면에 돌풍이 불거나 차량이 불규칙한 도로면을 통과하게 될 경우 차량이 좌우로 심하게 흔들리게 된다. 본 연구에서는 무게중심이 높은 차량의 안정성을 향상시키기 위해서 롤 모드 상에서 댐핑을 증가시킬 수 있는 제어기법이 제안되었다. 롤 운동의 댐핑을 제공하기 위해 요구되는 궤환신호로 앞 또는 뒤 또는 앞 뒤 바퀴의 조향각이 사용되었다. 그 이유는 그 신호들이 롤 운동과 매우 밀접하게 관련이 있기 때문이다. 제안된 제어기법은 중고속에서 매우 효과적이고 쇽업쇼바와는 달리 외적 입력에 대해 외란 모멘트를 생성하지 않고 롤 모드를 안정화시키는 것이 가능하다. 이론적으로 제시된 제어기법에 대한 타당성을 컴퓨터 시뮬레이션으로 확인하였다.

• 한국정밀공학회지
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• 제29권12호
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• pp.1368-1375
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• 2012

In this paper, a method for prediction of spread is proposed to design proper roll profile taking into account spread in shape rolling of angle bar. The effect of the process variables on spread, such as draught ratio, bending angle and aspect ratio, is analyzed by FE-analysis and response surface method (RSM). Roll profiles for equal angle bar are designed with the spread predicted by the regression equation. Effectiveness of the designed roll profiles are verified by FE-analysis in which the flange length, strain distribution, mean strain and roll torque are compared with those by Geuze. Finally, the proposed method is applied to the design of roll profile for unequal angle bar. As a result, the final product can be obtained within the allowable tolerance of ${\pm}0.5mm$ in length. Therefore, it is found that the prediction of spread can improve the efficiency of design roll profile in shape rolling of angle bar.

• 소성∙가공
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• 제24권3호
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• pp.212-217
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• 2015

SmartCrown is a system to control the plate crown by shifting the sine-shaped work rolls in the axial direction. The control range of the plate crown depends on a depth of sine-shaped roll profile because the roll radius varies continuously along the axial direction. When the roll profile is changed to improve the control range, the contact stress between the work roll and the back-up roll also changes. In the current study, the contact stress for various profiles and rolling conditions were analyzed using the finite element method and compared with results from Hertzian contact theory. A submodel method is used to increase the accuracy of the finite element analysis. The analysis results showed that the maximum increase in the contact stress was only 53MPa, so it is anticipated that no back-up roll spalling will occur.

• 한국산업융합학회 논문집
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• 제26권1호
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• pp.79-86
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• 2023

This study was investigated the effect of carbon on the micro-structure and hardness of ductile cast iron roll with internal curing capacity. Spheroidal graphite existed at roll body with rapid cooling, but granular graphite existed at roll neck with slow cooling. The volume fraction of graphite increased at roll body with rapid cooling, That of roll neck with slow cooling decreased, but graphite size increased. The volume fraction of cementite decreased, but volume fraction increased. The cementite size was larger at roll neck than roll body. The hardness was decreased at roll body and roll neck due to volume fraction of cementite. The hardness of roll body was higher than roll neck.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 2부
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• pp.937-940
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• 2010

본 연구는 fine blanking 프레스로부터 기능면으로 사용되는 100% clean cut 전단면을 얻는 fine blanking 공정에서 die roll을 최소화하기 위한 목적으로 성형 해석 및 실험적 방법을 통해 die chamfer 형상에 따라 성형되는 제품의 die roll size 변화를 검토한 것이다. fine blanking 과정을 묘사하기 위하여 deform 2D를 이용하여 성형 해석을 수행하여 die roll size를 예측하였으며, 실제 die chamfer가 다른 die insert를 제작하여 fine blanking 실험을 실시하여 die chamfer 형상에 따른 die roll size에 대한 해석 data와 실험 data를 비교 분석하여 die roll 길이 방향 size의 경향을 파악할 수 있었다. 이 연구 결과는 fine blanking 판재 성형에서 die roll을 최소화하기 위한 die chamfer 설계에 유용하게 적용될 것으로 판단된다.

• 한국정밀공학회지
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• 제21권9호
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• pp.95-102
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• 2004

A flexible incremental roll forming process has been developed by adopting the advantages of the incremental forming process and the roll forming process: i.e., inherent flexibility of the incremental forming process and continuous bending deformation of the roll forming process. It has an adjustable roll set as a forming tool composed of one upper center roll and two pairs of lower support rolls, which plays a key role during forming process. Through the experiments based on the various combinations of process parameters, it is shown that the incremental roll forming process is so effective as to manufacture various doubly curved sheet metals including concave-convex combination shapes in which there exists a line of inflection. The proposed relationship of the experimental parameters and the radius of curvature of the formed sheet boundary is found to be useful in prediction and control of the final shape.

• 대한기계학회논문집A
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• 제20권1호
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• pp.189-205
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• 1996

The twin-roll type strip continuous casting process(or direct rolling process) of steel materials is characterized by two rotating water cooled rolls receiving a steady supply of molten metal which solidifies onto the rolls. A solidification analysis of molten metal considering phase transformation and thermofluid is performed using finite diffefence method with curvilinear coordinate to reduce computing time and molten region analysis with arbitrary shape. An enthalpy-specific heat method is used to determine the temperatures inthe roll and the steel. The temperature distribution of cooling roll is calculated using two dimensional finite element method, because of complex roll shape due to cooling hole in rolls and improvemnt accuracy of calculation result. The energy equaiton of cooling roll is solved simultanuously with the conservation equaiton of molten metal in order to consider heat transfer through the cooling roll. The calculated roll temperature is compared to experimental results and the heat transfer coefficient between cooling roll surface and rolling material(steel) is also determined from comparison of measured roll temperature and calculated temperature.