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Mg 합금 저항 점 용접의 연속 타점 수명에 미치는 전극 형상의 영향
최동순(Dongsoon Choi),강문진(Moonjin Kang),류재욱(Jaewook Ryu),김동철(Dongcheol Kim) 한국자동차공학회 2014 한국 자동차공학회논문집 Vol.22 No.4
According to weight lightning trend of automobile body, necessity of resistance spot welding (RSW) of Mg alloy on automobile industry is increasing rapidly because of the highest specific strength among commercial metals. Mg alloy has low electric resistance and high thermal conductivity like as Al alloy, so that needs applying high current in short time when welding. Thick oxide film of Mg alloy pollutes the electrodes and makes partial current carrying paths when on welding. Partial current carrying paths signify excessive concentration of current. There can initiate expulsion easily and reduces electrode life rapidly. Generating partial current carrying paths and expulsions are influenced by shapes of electrode. Therefore, electrode life also influenced by shape. In this study, we perform life test of RSW electrode of radius type. Measure tensile shear load and nugget size every spot alternately. As a result, radius type electrode can extend life over twice as dome type electrode.
돔형 전극을 사용한 마그네슘 합금 저항 점용접의 전극 수명 평가
최동순,황인성,김동철,강문진,Choi, Dong-Soon,Hwang, In-Sung,Kim, Dong-Cheol,Kang, Moon-Jin 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.6
Magnesium alloy is used on parts of aircraft and electronic equipment because of the highest specific strength among the common metal materials. Recently, studies about appling magnesium alloy sheet to automotive bodies are on the increase rapidly. For application to automotive bodies, researches about characteristics of resistance spot welding of magnesium alloy sheet are essential. Magnesium alloy has low boiling point, so getting sound bead shape is difficult when appling varies welding processes. Resistance spot welding is also particular about setting optimum welding conditions because of spatter generation, pores and cracks occurrence in nugget. And life of electrodes is very short because of alloying with copper that main material of electrodes. This requires frequent dressing and replacement of electrodes and decrease in productivity of resistance spot welding on magnesium alloy. Therefore in this study, for effective analysis of changes in tensile shear load and nugget size during electrode life test, evaluate detail characteristics of resistance spot welding on magnesium alloy sheet using dome type electrode.
Process Tape를 사용한 마그네슘 합금의 저항 점 용접 특성
최동순,김동철,강문진,Choi, Dong-Soon,Kim, Dong-Cheol,Kang, Moon-Jin 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.3
Recently, studies about application of magnesium alloy sheet to automotive bodies are on the increase. For application to automotive bodies, researches about characteristics of resistance spot welding of magnesium alloy sheet are essential. Electrode life of resistance spot welding of magnesium alloy is very short due to sticking of magnesium alloy to copper alloy electrode. To increase electrode life, most effective method is inserting cover plate between electrode and magnesium sheet. But application of cover plate to actual process is difficult and decreases welding productivity. Process tape supplied automatically as cover plate can minimize lose of productivity and increase welding quality. In this study, resistance spot welding of magnesium alloy is carried out with applying process tape. Acceptable welding current region according to electrode force and welding time is determined.
김용혁(Yong-Hyuk Kim) 대한전기학회 2016 전기학회논문지 P Vol.65 No.3
The transient characteristics of the Mg/Air fuel cell were ascribed to the load current, electrolyte concentrations, air electrode area and electrode distance. It was found that transient phenomena occurred in the load current, which is due to activate of the oxidation and reduction reaction process. The transient time increase with the load current increase. The transient characteristics were investigated with regard to internal resistance. The maximum power output analysis was employed in order to explain the delayed action under various experimental conditions. The internal resistances had a significant effect on the transient characteristics. The transient curves thus obtained were in almost agreement with internal resistance characteristics.
Park, J.H.,Eom, J.H.,Park, B.J.,Park, K.T.,Lee, S.Y.,Kim, K.S.,Yoon, S.G. Elsevier 2015 CURRENT APPLIED PHYSICS Vol.15 No.11
Thin-film multi-layer ceramic capacitors (MLCCs) were prepared using high-dielectric constant Bi<SUB>2</SUB>Mg<SUB>2/3</SUB>Nb<SUB>4/3</SUB>O<SUB>7</SUB> thin-films deposited at room temperature via radio-frequency magnetron sputtering. The multi-layer capacitors, in sizes 0402, 0603 and 1005, were well equipped with both inner and outer Cu electrodes. The capacitances of the bi-layer capacitors were twice that of the single-layer version in sizes 0402, 0603, and 1005. The 200 nm-thick Bi<SUB>2</SUB>Mg<SUB>2/3</SUB>Nb<SUB>4/3</SUB>O<SUB>7</SUB> thin-films would be suitable for thin-film multi-layer capacitor applications.
박지현,엄지호,박병주,박기태,이수열,김경수,윤순길 한국물리학회 2015 Current Applied Physics Vol.15 No.11
Thin-film multi-layer ceramic capacitors (MLCCs) were prepared using high-dielectric constant Bi2Mg2/ 3Nb4/3O7 thin-films deposited at room temperature via radio-frequency magnetron sputtering. The multi-layer capacitors, in sizes 0402, 0603 and 1005, were well equipped with both inner and outer Cu electrodes. The capacitances of the bi-layer capacitors were twice that of the single-layer version in sizes 0402, 0603, and 1005. The 200 nm-thick Bi2Mg2/3Nb4/3O7 thin-films would be suitable for thin-film multi-layer capacitor applications.
PPV-copolymer 합성 및 고분자 유기EL 소자 제조
김은옥 수원대학교 기능성생명소재연구소 2002 자연과학연구논문집 Vol.1 No.-
Copolymer derived from poly(p-phenylenevinylene) (PPV) which contains blue light-emitting part and soluble alkyl group in polymer chain was synthesized through Wittig reaction. The resulting copolymer, poly(octanedioxy-co-dMPPV), was soluble in common organic solvents and spin-coated on the ITO electrode. Light emitting diodes(LEDs) were fabricated by sandwitching the emissive copolymer between ITO and Al electrode. Operation voltage of polymer LEDs were lowered by interposing a LiF or Mg layer between Al electrode and copolymer layer.