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Test methodology for evaluating surface damages of polymers and coatings
원종일 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
A new test methodology based on materials science and mechanics tools for evaluating scratch and mar resistance of polymers has recently been developed and approved as a new ISO standard. This new test method allows for simple, unambiguous quantitative evaluation and ranking of scratch and mar resistance of polymeric materials and coatings. Especially, mar behavior and visibility have also been investigated to correlate between the material parameters and surface damage observed for coatings. The usefulness of the new ISO methodology for fundamental understanding of scratch and mar behaviors of polymers and coatings will be presented. Experimental approaches for how to improve scratch properties will also be discussed.
역사이클하중하에서의 균열길이 측정법에 따른 파괴저항곡선의 평가
원종일,우흥식,석창성 한국산업안전학회 1998 한국안전학회지 Vol.13 No.4
J-R curve tests were performed on 1T compact specimens of SA516 Gr. 70 carbon steels under reverse cyclic loading. A Direct-Current Potential Drop (DCPD) method, one of the nondestructive techniques to detect flaw of structure, is being increasingly used for monitoring crack initiation and stable crack growth in typical fracture mechanics specimens for J-R testing. In many aspects this method is simpler than the unloading compliance method. The objective of this paper is to evaluate the J-R Curve according to the crack length measurement techniques under reverse cyclic loading. In order to prove the reliability and repeatability of the DCPD method, the crack length measured by using DCPD method was compared to one determined from unloading compliance. Consequently, this DCPD method correlated well with J-R curves and crack extension measurements determined from unloading compliance method.
원종일 한국고분자학회 2009 Macromolecular Research Vol.17 No.10
The mechanical and thermal behaviors of polyamide-6/clay nanocomposites were studied using the continuum- based, micromechanical models such as Mori-Tanaka, Halpin-Tsai and shear lag. Mechanic-based model prediction provides a better understanding regarding the dependence of the nanocomposites’ reinforcement efficiency on conventional filler structural parameters such as filler aspect ratio (α), filler orientation (S), filler weight fraction (ψf), and filler/matrix stiffness ratio (Ef /Em). For an intercalated and exfoliated nanocomposite, an effective, filler-based, micromechanical model that includes effective filler structural parameters, the number of platelets per stack (n) and the silicate inter-layer spacing (d001), is proposed to describe the mesoscopic intercalated filler and the nanoscopic exfoliated filler. The proposed model nicely captures the experimental modulus behaviors for both intercalated and exfoliated nanocomposites. In addition, the model prediction of the heat distortion temperature is examined for nanocomposites with different filler aspect ratio. The predicted heat distortion temperature appears to be reasonable compared to the heat distortion temperature obtained by experimental tests. Based on both the experimental results and model prediction, the reinforcement efficiency and heat resistance of the polyamide-6/clay nanocomposites definitely depend on both conventional (α, S, ψf, Ef /Em) and effective (n, d001) filler structural parameters.
Reverse-Conducting IGBT Using MEMS Technology on the Wafer Back Side
원종일,고진근,이태복,오형승,이진호 한국전자통신연구원 2013 ETRI Journal Vol.35 No.4
In this paper, we present a 600-V reverse conducting insulated gate bipolar transistor (RC-IGBT) for soft and hard switching applications, such as general purpose inverters. The newly developed RC-IGBT uses the deep reactive-ion etching trench technology without the thin wafer process technology. Therefore, a freewheeling diode (FWD) is monolithically integrated in an IGBT chip. The proposed RC-IGBT operates as an IGBT in forward conducting mode and as an FWD in reverse conducting mode. Also, to avoid the destructive failure of the gate oxide under the surge current and abnormal conditions, a protective Zener diode is successfully integrated in the gate electrode without compromising the operation performance of the IGBT.
높은 홀딩전압을 갖는 사이리스터 기반 새로운 구조의 ESD 보호소자
원종일,구용서,Won, Jong-Il,Koo, Yong-Seo 한국전기전자학회 2009 전기전자학회논문지 Vol.13 No.1
본 논문에서는 높은 홀딩 전압을 갖는 사이리스터(SCR; Silicon Controlled Rectifier)구조에 기반 한 새로운 구조의 ESD(Electro-Static Discharge) 보호 소자를 제안하였다. 홀딩전압은 애노드단을 감싸고 있는 n-well에 p+ 캐소드를 확장시키고, 캐소드단을 n-well로 추가함으로써 홀딩전압을 증가시킬 수 있다. 제안된 소자는 높은 홀딩전압 특성으로 높은 래치업 면역성을 갖는다. 본 연구에서 제안된 소자의 전기적 특성, 온도특성, ESD 감내특성을 확인하기 위하여 TCAD 시뮬레이션 툴을 이용하여 시뮬레이션을 수행하였다. 시뮬레이션 결과 제안된 소자는 10.5V의 트리거 전압과 3.6V의 홀딩전압을 갖는다. 그리고 추가적인 n-well과 확장된 p+의 사이즈 변화로 4V이상의 홀딩전압을 갖는 것을 확인하였다. The paper introduces a silicon controlled rectifier (SCR)-based device with high holding voltage for ESD power clamp. The holding voltage can be increased by extending a p+ cathode to the first n-well and adding second n-well wrapping around n+ cathode. The increase of the holding voltage above the supply voltage enables latch-up immune normal operation. In this study, the proposed device has been simulated using synopsys TCAD simulator for electrical characteristic, temperature characteristic, and ESD robustness. In the simulation result, the proposed device has holding voltage of 3.6V and trigger voltage of 10.5V. And it is confirmed that the device could have holding voltage of above 4V with the size variation of extended p+ cathode and additional n-well.