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무가압침투법에 의한 전자패키징 재료용 Al / SiCp 복합재료의 제조
최일동,김성준,박익민 ( Il Dong Choi,Sung Joon Kim,Ik Min Park ) 한국주조공학회 1996 한국주조공학회지 Vol.16 No.1
N/A Infiltration behavior of Al-Mg alloys in SiC_p powder bed using pressureless infiltration technique have been studied. The manufacturing of Al/SiC_p composites by pressureless infiltration was successful when Mg was added over 8% in Al alloy matrix. Processing time and temperature to complete Infiltration through SiC_p bed was decreased with increasing Mg content in Al alloy. When Mg powder was added in SiC_p bed, processing temperature for successful infiltration was decreased. Volume fraction of SiC_p in composites was increased with increasing the mixing ratio of coarse SiC particles.
SI가솔린 기관에서 흡기조성에 따른 연소 및 배기특성에 관한 실험적 연구
최일동(Il-Dong Choi),김치원(Chi-Won Kim),윤창식(Chang-Sik Yoon),김기복(Gi-Bok Kim),이병호(Byung-Ho Lee) 한국산업융합학회 2017 한국산업융합학회 논문집 Vol.20 No.1
In this experimental study, it is designed and used the test engine bed which is installed with the exhaust gas recirculation, and in addition to equipped using by oxygen adder. It has been tested and analyzed the combustion and emission characteristics, cycle variability and engine performance by controlling the oxygen volume fraction, EGR rate, engine speed and equivalence ratio.
스파크 점화기관에서 흡입 공기 중 산소체적분율의 변화가 연소 및 배기가스 조성에 미치는 영향에 관한 연구
최일동(il Dong Choi),김치원(Chi Won Kim),이병호(Byung Ho Lee) 한국자동차공학회 2016 한국자동차공학회 지부 학술대회 논문집 Vol.2016 No.10
The change in the oxygen volume fraction of the inlet air of the spark ignition engine configuration an experimental apparatus to interpret the effects of combustion and the exhaust gas composition and was experiments using a suitable measuring instrument, in this chapter discusses the experimental apparatus and method. When the volume fraction of oxygen in the intake air increases as described above, the combustion pressure was measured as a way to ensure that the combustion temperature rises, and increase the combustion speed. And the stability of combustion and analyzed using the apparatus for continuously acquired by the average number of cycles than the pressure of the pressure cycle. Depending on the combustion chamber geometry of the spark ignition engine is the ignition position, the flow in the cylinder, the ignition characteristics that are affected. But allows the case that the oxygen volume fraction as in the study change in factors related to the engine and the factor associated with the flow are able to determine the characteristics of the combustion, and analysis using the pressure change of the engine when the fraction of oxygen volume change since the same condition
스파크점화 기관에서 흡기 조성 중 연소 및 배기 특성에 관한 연구
최일동(il Dong Choi),김치원(Chi Won Kim),이병호(Byung Ho Lee) 한국자동차공학회 2016 한국자동차공학회 학술대회 및 전시회 Vol.2016 No.11
The multi-point fuel injection in a spark ignition engine is applied is guided through the inlet valve into the cylinder is mixed with fuel and the air before the intake valve, the piston rises and compresses the mixture through the crankshaft rotational motion. It is generated by the discharge in the spark plug in the compression top dead center electrode spark nuclear propagates in the compressed mixture. Thus, very important because the damage to the living organisms or environmental contaminants in the exhaust gas generated when the mixture is burned. While maintaining good fuel economy from the stoichiometric operation, it reduces both carbon monoxide and nitrogen oxide emissions, combustion instability or unstable behavior due to a misfire by the operating parameters are generating lots of exhaust substances that pollute the earth. And the engine constitute a damage.
반응용탕단조법에 의한 (Al2O3+Si)/Mg 하이브리드 금속복합재료의 제조 및 특성평가
오동현 ( Dong Hyun Oh ),전상혁 ( Sang Hyuk Jeon ),박익민 ( Ik Min Park ),조경목 ( Kyung Mox Cho ),최일동 ( Il Dong Choi ) 한국주조공학회 2000 한국주조공학회지 Vol.20 No.1
In the present study, (10%Al2O3+5%Si)/AZ91 Mg hybrid composite was fabricated using the squeeze casting method. During squeeze casting, molten Mg was infiltrated into the preform of 10%Al2O3+5%Si and reaction product of Mg2Si intermetallic compound was formed by the reaction between molten Mg and Si powder. Microstmcture has been observed and mechanical properties were evaluated for the reaction squeeze cast (RSC) hybrid composite. It was found that Si powder totally reacted with molten Mg to form Mg2Si. Reinforcement (Al2O3) and the reaction product (Mg2Si) are fairly uniformly distributed in Mg matrix for the squeeze cast hybrid composite. Mechanical properties were improved with hybridization of reinforcements, namely higher hardness and enhanced wear resistance comparing squeeze cast (l5%A2lO3)/AZ91 Mg composite.
용융아연도금 강판 저항 점 용접 시 정전류 및 적응제어 적용에 따른 연속타점 특성 평가 및 고찰
서정철,최일동,손홍래,지창욱,김치호,서성부,서진석,박영도,Seo, Jeong-Chul,Choi, Il-Dong,Son, Hong-Rea,Ji, Changwook,Kim, Chiho,Suh, Sung-Bu,Seo, Jinseok,Park, Yeong-Do 대한용접접합학회 2015 대한용접·접합학회지 Vol.33 No.2
With using adaptive control of the resistance spot welding machine, the advantage on electrode life time for galvanized steels has been addressed. This study was aimed to evaluate the electrode life time of galvanized steels with applying the constant current control and the adaptive control resistance spot welding process for a comparison purpose. The growth in diameter of electrode face was similar for both the constant current and the adaptive control up to 2000 welds. The button diameter was decreased with weld numbers, however, sudden increase in button diameter with use of the adaptive control after 1500 welds was observed. The peak load was continuously decreased with increasing number of welds for both the constant current and the adaptive control. The current compensation during a weld was observed with using the adaptive control after 1800 welds since the ${\beta}$-peak on dynamic resistance curve was detected at later weld time. The current compensation with adaptive control during resistance spot welding enhanced the nugget diameter at the faying interface of steel sheets and improved the penetration to thinner steel sheet.
변형구배 결정소성 유한요소해석법을 이용한 니켈기 다결정 합금의 Hall-Petch 관계 모델링
최윤석,조경목,남대근,최일동,Choi, Yoon Suk,Cho, Kyung-Mox,Nam, Dae-Geun,Choi, Il-Dong 한국재료학회 2015 한국재료학회지 Vol.25 No.2
A strain-gradient crystal plasticity constitutive model was developed in order to predict the Hall-Petch behavior of a Ni-base polycrystalline superalloy. The constitutive model involves statistically stored dislocation and geometrically necessary dislocation densities, which were incorporated into the Bailey-Hirsch type flow stress equation with six strength interaction coefficients. A strain-gradient term (called slip-system lattice incompatibility) developed by Acharya was used to calculate the geometrically necessary dislocation density. The description of Kocks-Argon-Ashby type thermally activated strain rate was also used to represent the shear rate of an individual slip system. The constitutive model was implemented in a user material subroutine for crystal plasticity finite element method simulations. The grain size dependence of the flow stress (viz., the Hall-Petch behavior) was predicted for a Ni-base polycrystalline superalloy NIMONIC PE16. Simulation results showed that the present constitutive model fairly reasonably predicts 0.2%-offset yield stresses in a limited range of the grain size.
Al-Si 도금된 핫스탬핑 보론강의 저항 점용접시 도금층 용융거동 및 너겟 성장에 관한 연구
지창욱 ( Chang Wook Ji ),최일동 ( Il Dong Choi ),김양도 ( Yang Do Kim ),박영도 ( Yeong Do Park ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.11
The effect of coating melting behavior on nugget growth during resistance spot welding of hot- stamped boron steels was evaluated. A comparative analysis of the dynamic resistance for bare hot stamped and Al-Si coated hot stamped boron steels was carried out. The dynamic resistance curve of Al-Si coated hot stamped boron steel was higher than bare hot stamped boron steel during the whole stages of weld time. Higher α-peak and β-peak for Al-Si coated hot stamped boron steel resulted in larger nugget size at higher than 4.0 kA weld current owing to non-linear layer structure of alloyed coating, which appears to restrict the current passage through the faying interface. In the case of Al-Si coated hot-stamped boron steel, most of the Al-Fe intermetallic coatings are expected to be pushed away while in the liquid state at the faying interface. The pressure build up during the early stage of weld pushes the liquid Al-Fe intermetallic coating towards the edge of the faying interface. The continuous liquid state of Al-Fe intermetallic through the faying interface ensures the large contact area for the current passage to enlarge the nugget diameter. (Received June 1, 2014)
결정성 SiO2 충진 EMC ( Epoxy Molding Compounds ) 봉지재의 성형조건 및 물성에 관한 연구
김원호,배종우,강호영,이무정,최일동 ( Wonho Kim,Jong Woo Bae,Ho young Kang,Moo Jung Lee,Il Dong Choi ) 한국공업화학회 1997 공업화학 Vol.8 No.3
회로 설계의 고속화, 고성능화 경향으로 인해 반도체 봉지제의 유전특성은 회로실행과 신뢰성에 지대한 영향을 미친다. 또한 칩이 고집적화됨에 따라 신뢰성에 영향을 주는 방열성이 주요 인자가 되고 있다. 결과적으로 선진적인 반도체 봉지재 제조에 있어 4가지 주요한 특성은 낮은 유전상수 값, 높은 열전도도, 상대적으로 낮은 열팽창계수, 낮은 제조원가 등이다. 본 연구에서는 에폭시 봉지제의 고성능화를 위해 에폭시 모제의 충진제로서 결정성 실리카를 사용하였다. 그 결과 실리카 부피량 60∼70%일 때, 보다 뛰어난 물성을 갖는 반도체 봉지재를 제조할 수 있음을 확인하였다. 또한 이 실험 과정에서 반도체 봉지제의 성형조건도 설정할 수 있었다. Due to the trends of faster and denser circuit design, dielectric properties of packaging materials for semiconductor will give a greater influence on performance and reliability. Also as chip becomes more densified, thermal dissipation becomes a critical reliability issue. Consequently, four important properties for manufacturing semiconductor packaging materials are low values of dielectric constant, high values of thermal conductivity, relatively low values of thermal expansion coefficient and low cost. Thus, in this study, to achieve increased performance of EMC, crystalline silica was selected as the filler for epoxy matrix. As a result, when the volume percent of crystal silica was 60-70%, good properties as packaging materials for semiconductor were achieved. In addition, overall molding condition of EMC in this experiment was established.