• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.187-189
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• 2006

Transient finite element method for analysis of moving coil needs many number of elements and much time to make calculation. Therefore, induction heating process for moving coil was simulated by traveling the position of the heating planes in this paper. In the magnetic and thermal analyses, temperature-dependent magnetic and thermal material properties were considered. Finite element program was developed and finite element results were compared with the experimental results.

• 전자공학회논문지
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• 제52권5호
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• pp.197-205
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• 2015

함정용 전자광학추적장비 열영상센서부 전면창의 신뢰성 및 성능 개선을 위해 플라즈마 화학기상증착법을 통해 제작되는 DLC 박막을 제안하였다. DLC 박막은 현재 사용되고 있는 실리콘 박막과 비교하여 뛰어난 강도와 낮은 마찰, 화학적 안정성이 우수하며 이로 인해 해상 환경에서 필연적으로 발생하는 열영상센서 전면창의 표면 박리를 최소화할 수 있는 장점이 있다. 본 실험을 통해, DLC 박막이 갖는 물리적 특성을 바탕으로 다양한 전자광학장비에 적용이 가능함을 확인하였다.

• 한국자동차공학회논문집
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• 제19권4호
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• pp.107-113
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• 2011

Coolant rubber hoses for automotive radiators under thermal and mechanical loadings can be degraded and thus failed due to the influences of the locally formed electricity. In this study, an advanced test method was developed to simulate the failure problem of the rubber hose. For carbon black filled EPDM (ethylene-propylene dine monomer) rubber used as a radiator hose material the ageing behaviors by the electro-chemical stresses combined with a tensile strain were analyzed. As the tensile strain increased, the current of the rubber specimen reduced indicating an increase of the internal defects and electrical resistance of the rubber specimen. Elongation at break and IRHD hardness rapidly decreased with increasing the ageing time. Both electro-chemical stress and mechanical tensile stress clearly accelerated the degradation of EPDM rubber.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.59-66
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• 2011

This work treat the modeling and simulation of non-linear dynamic behavior of a web winding process during traction. We designate by a winding process any system applying the cycles of unwinding, transport, treatment, and winding to various flat products. This system knows several constraints, such as the thermal effects caused by the frictions, and the mechanical effects provoked by metal elongation, that generates dysfunctions due to the influence of the process conditions. Several controllers are considered, including Proportional-integral (PI) and Backstepping control. This paper presents the study of Backstepping controls strategy of the winding system. Our winding system is simulated in MATLAB SIMULINK environment, the results obtained illustrate the efficiency of the proposed control with no overshoot, and the rising time is improved with good disturbances rejections comparing with the classical control law.

• 한국정밀공학회지
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• 제30권2호
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• pp.241-246
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• 2013

This paper reports fabrication and characterization of cellulose Electro-Active Paper (EAPap) with increased thickness. Usual thickness of cellulose EAPap was $15{\mu}m$. This thickness needs to be increased to enhance the mechanical force output of EAPap. To fabricate thick cellulose EAPap, the fabrication process parameters including casting and drying processes should be investigated. In this paper, the casting thickness is increased from $800{\mu}m$ to $1500{\mu}m$, and heating times on a hot plate before and after curing process are introduced at 40 and $60^{\circ}C$ for 30 and 60 minutes, respectively. Thickness measurement, Thermal Gravitational Analysis (TGA), UV-transmittance, Young's modulus, and piezoelectric charge constant are measured. Heated EAPaps with increased thickness have similar TGA result, higher transmittance, higher Young's modulus and lower piezoelectric charge constant.

• 한국세라믹학회지
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• 제46권2호
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• pp.211-218
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• 2009

For the Y5V characteristic MLCC which is very prone to crack, it is important to to find out the basic cause of the crack. After finding out the crack origin, the materials and processes should be developed to remove the crack. The microstructures of the cracks were investigated using the fractographic method for the various types of cracks such as an exterior crack, a cyclic thermal shock crack, and an piezo-electric crack. It was found out that the crack origin was the pore at the end of the Ni inner electrode after bake-out. Even though the three dimensional crack shapes were different, the crack origins were seemed to be similar. The exterior crack could grow from the origin with the aids of residual and applied stress. FEM (finite element method) analysis was used to calculate the stress distribution of residual and applied stress. And the concept of fracture mechanics was applied for the explanation of the crack initiation and propagation from the stresses concentration.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.723-724
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• 2006

In this study, superconducting coil arrangements and cryostat concept design were conducted for the development of 13.2kV/630A bifilar winding type high temperature superconducting(HTS) fault current limiter(FCL) with YBCO coated conductor(CC) wire. The coil consists of several layers with unique non-inductive solenoid winding method. Six types of HTS coil arrangements were investigated for the optimal insulation design of HTS FCL. And, conceptual design of cryostat was conducted for the decrement of thermal invasion and the prevention of low voltage insulation breakdown in the LHe which is used as pressurization gas in sub-cooling condition of liquid nitrogen(LN2). As the results, it was found that the modified suspended type cryostat with horizontal coil arrangement is beneficial to the insulation design of 13.2kV level bifilar winding type HTS FCL.

• 한국광학회지
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• 제9권4호
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• pp.215-220
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• 1998

전기광학 폴리머(electro-optic polymer)의 다양한 전기광학 특성을 동시에 측정하기 위한 실험장치와 기법을 제안하였다. 제안된 실험장치를 이용하여 폴링(poling)전 측쇄(side-chain)결합형 전기광학 폴리머 필름에 강한 de 및 ac 전기장을 인가시 발생하는 전기광학 효과와 복굴절을 관측하였다. 다양한 폴링조건에 따른 전기광학 계수의 의존성을 실시간으로 측정하였다. 폴링후의 폴리머 필름의 열적 안정성을 평가하기 위하여 전기광학 효과의 이완현상을 측정하여 잘 알려진 전기광학 폴리머와 특성을 비교하였다. 이 실험장치는 실험과정과 시간을 줄일 수 있다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 추계학술발표대회
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• pp.5-7
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• 2019

열화상 시스템은 물체로부터 발산되는 적외선을 영상화하여 물체를 탐지하는 장점으로 인해 군사 분야는 물론 현재 민수 분야(자동차, Security 시스템)에 활용분야가 넓어지고 있다. 기존에는 대부분 FPGA 기반으로 열화상 열상 모듈을 개발하였지만 민수 분야에 다양한 요구사항 및 범용성에 유연한 대처가 힘든 실정이다. 따라서 다양한 요구사항과 범용성을 만족하기 위한 시스템의 필요성이 대두되었다. 본 논문에서는 상용 이미지 프로세서를 이용한 열화상 영상 처리 시스템을 제안한다. 제안된 시스템은 기존 FPGA 기반 시스템이 아닌 상용 이미지 프로세서를 사용함으로써 범용 영상 입·출력 인터페이스 및 각종 디바이스를 지원함에 따라 다양한 요구사항과 범용성을 만족한다. 따라서 시스템이 구축이 되면 뛰어난 접근성으로 인하여 시스템 추가/변경 시 기존의 시스템에 비해 개발 비용 및 기간을 단축할 수 있으며 그로 인하여 다양한 고객 요구사항 만족, 개발 비용 및 시간 단축, 제품 출시일 등 다양한 이점을 얻을 것으로 예상한다.

• 대한치과기공학회지
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• 제30권2호
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• pp.17-22
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• 2008

The purpose of this study was to observe the thermal expansion of the inlay waxes at temperature. Inlay pattern wax shows not only a high coefficient of expansion but also a tendency to warp or distort when allowed to stand unrestrained. The thermal expansion of inlay waxes was tested according to the treatment conditions for 10 minutes at $40^{\circ}C$ The thermal expansion of inlay waxes at various temperatures was measured with an electro dial gauge. The results were as fellows: 1. It is shown that the rate of thermal expansion of wax A is 0.2%, wax B is 0.29%, wax C is 0.38%, and wax D is 0.22% at $40^{\circ}C$ 2. It is shown that the coefficient of thermal expansion of wax A is $106{\times}10^{-6}/^{\circ}C$, wax B is $152{\times}10^{-6}/^{\circ}C$, wax C is $199{\times}10^{-6}/^{\circ}C$, and wax D is $116{\times}10^{-6}/^{\circ}C$ at $40^{\circ}C$ 3. The thermal expansion of the inlay waxes at $40^{\circ}C$ was shown to increase in the order of wax C, B, D, A.