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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.
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.
Surface Characterization and Morphology in Ar-Plasma-Treated Polypropylene Blend
원종일,최길영 한국고분자학회 2009 Macromolecular Research Vol.17 No.11
Surface modifications using a radio frequency Ar-plasma treatment were performed on a polypropylene (PP) blend used for automotive bumper fascia. The surface characterization and morphology were examined. With increasing aging time, there was an increase in wettability, oxygen containing polar functional groups (i.e., C-O, C=O and O-C=O) due to oxidation, the amount of talc, and bearing depth and roughness on the PP surface, while there was a decrease in the number of hydrocarbon groups (i.e., C-C and C-H). AFM indicated that the Ar-plasmatreatment on a PP blend surface transforms the wholly annular surface into a locally dimpled surface, leading to an improvement in wettability. SEM showed that the PP layer observed in the non-plasma-treated sample was removed after the Ar-plasma treatment and the rubber particles were exposed to the surface. The observed surface characterization and morphologies are responsible for the improved wettability and interfacial adhesion between the PP blend substrate and bumper coating layers.
원종일,석창성,김수용,김동중,안하늘,박은수 한국산업안전학회 1999 한국안전학회지 Vol.14 No.4
In this study, theoretical stress field analysis near the crack tip under tension-compression loading was performed. The results of the theoretical stress analysis were compared to the results of Finite Element Method(FEM). From this study, generation of tensile residual stress at crack tip was proved after 1-cycle of tension-compression loading, and the fracture toughness and the fracture load of a structure can be decreased by the residual stress.
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.