• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 International Symposium
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• pp.183-199
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• 2002

Reliability.The reliability strongly depended on the CTE of underfill resin..The fractured portion was identical with the maximum plastic equivalent strain..1 % or less value of the maximum plastic equivalent strain certified more than 1000 cycle of TCT life. UFB.Bonding accuracy was confirmed within2$2{\mu}{\textrm}{m}$..The fundamental bondability of UFB was confirmed with no damage around aluminum pads. Some dislocations and vacancies were observed at the interface, however, the atomic level bonding was confirmed. CBB.Dry process was applied to UBM removal.

• 한국생산제조학회지
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• 제8권1호
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• pp.112-118
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• 1999

Aluminum alloy, which is advantageous to machining and injection, makes a great contribution to shortening in delivery time, infection cycle time and reducing expense. This study presents machining conditions for mild materials and describes the difference between theoretical and practical machined surface roughnesses affected by various machining conditions. Machining results have been evaluated and analyzed under varying machining conditions. Special properties of the mild materials have been presented by the quantitative analysis and the optimal machining condition has been proposed for the mild materials.

• 대한기계학회논문집A
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• 제37권2호
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• pp.279-285
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• 2013

소형 복합재료 프로펠러를 제작하기 위한 기존의 알루미늄 몰드를 복합재료 몰드로 대체하기 위한 타당성 연구를 수행하였다. 소형 알루미늄 프로펠러의 세 날개는 복합재료 몰드를 만들기 위해 플러그로서 사용되었다. GRPG 복합재료 몰드와 프로펠러는 실내온도에서 압축과 진공법을 이용하여 불포화된 폴리에스테르 수지, Epovia 겔코트, 우븐과 매트 유리 섬유 등으로 만들어졌다. 표면의 경도와 거칠기, 압축과 흡입 몰드에 의한 강도와 변형은 실험에 의해 결정되었다. 결과는 ISO 484/2 규격과 몇몇의 알루미늄 합금과 비교되었다. 결과로부터 몰드의 변형은 날개 두께에 관한 공차를 만족하는 것을 알 수 있었다. GRPG 복합재료 몰드의 몇 가지 특징은 알루미늄 합금 몰드보다 좋았으며(표면의 매끈함, 중량, 작동 능력과 비용), 다른 몇 가지 특징들은 비슷하였다(분리 능력과 라이프 사이클). 결과적으로 복합재료 몰드는 소형 복합재료 선박 프로펠러를 만들기에 적합한 것을 알 수 있었다.

• 방사성폐기물학회지
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• 제3권2호
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• pp.95-104
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• 2005

TRIGA 연구로의 해체 시 발생하는 금속성 폐기물의 용융기술을 확립하기 위한 기초연구로 전기로 내에서 방사성 핵종(Co, Cs, Sr)을 포함한 알루미늄의 용융 시 용융온도, 용융시간 및 플럭스(flux)의 종류가 핵종의 분배 거동에 미치는 영향을 조사하였다. 플럭스의 종류에 따라 다소 차이는 있으나, 플럭스의 첨가로 알루미늄 용융체의 유동성이 증가됨을 확인할 수 있었다 용융 후주괴(ingot) 및 슬래그(slag) 시료의 XRD분석을 통해 핵종이 주괴에서 슬래그 상으로 이동하고 슬래그를 구성하고 있는 산화알루미늄과 결합하여 안정한 화합물을 형성함을 알 수 있었다. 슬래그의 발생량은 용융온도와 용융시간이 증가할수록 증가하는 경향을 보였으며, 증가속도는 플럭스의 종류에 따라 차이를 보였다. 핵종 중 Co는 용융온도가 증가함에 따라 주괴 내 에서는 감소하였으나 슬래그 상에서는 증가하는 경향을 보였으며, 실험조건에 따라 최대 90$\%$까지 주괴에서 슬래그로 이동하였다. 휘발성이 강한 Cs과 Sr은 대부분이 슬래그와 분진으로 이동하여 매우 높은 제염계수를 얻을 수 있었다.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.243-248
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• 2007

The durability of a cylinder head is influenced by the thermal and mechanical history during the manufacturing process, as well as engine operation. In order to improve the durability of cylinder head, both load from engine operation and the preload conditions from the manufacturing process must be considered. The aluminum cylinder head used for a HSDI diesel engine is investigated to reduce the possibility of high cycle fatigue crack in this study. FE analysis is performed to elucidate the mechanism of high cycle fatigue crack in the HSDI diesel cylinder head. Two separate approaches to increase the durability of the cylinder head are discussed: reducing load from engine operation and re-arranging preload conditions from the manufacturing process at the critical location of the cylinder head. Local design changes of the cylinder head and modification of pretension load in the cylinder head bolt were investigated using FE analysis to relieve load at the critical location during engine operation. Residual stress formed at the critical location during the manufacturing process is measured and heat treatment parameters are changed to re-arrange the distribution of residual stress. Results of FE analysis and experiments showed that thorough consideration of the manufacturing process is necessary to enhance the durability of the cylinder head.

• 한국생산제조학회지
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• 제22권1호
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• pp.173-177
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• 2013

The purpose of this paper is to investigate the influences on mechanical properties of two-stroke cycle motor pistons manufactured by casting, conventional forging and powder forging, through the comparison of characteristics, merits and disadvantages of each forming technology. For each forming technology, the optimal process parameters were determined through the experiments for several conditions, and microstructure, hardness, tensile strength and elongation of pistons are compared and analyzed. In conventional forging process, material temperature was $460^{\circ}C$ and the die temperature was $210^{\circ}C$ for the Al 4032. The optimal condition was found as solution treatment under $520^{\circ}C$ for 5 hours, quenching with $23^{\circ}C$ water, and aging under $190^{\circ}C$ for 5 hours. In powder forging process, the proper composition of material was determined and optimal sintering conditions were examined. From the experiment, 1.5% of Si contents on the total weight, $580^{\circ}C$ of sintering temperature, and 25 minutes of sintering time were determined as the optimal process condition. For the optimal condition, the pistons had 76.4~78.3 [HRB] of hardness, and 500 [MPa] of tensile strength after T6 heat treatment.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.13-14
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• 2008

$Al_2O_3$ thin films were deposited on GaN (0001) by remote plasma atomic layer deposition (RPALD) technique using trimethylaluminum (TMA) precursor and oxygen radicals in the temperature range of 25 ~ $500^{\circ}C$. Growth rate per cycle was varied with substrate temperature from 1.8 $\breve{A}$/ cycle at $25^{\circ}C$ to 0.8 $\breve{A}$/cycle at $500^{\circ}C$. The chemical structure of the $Al_2O_3$ thin films was studied using X-ray photo electron spectroscopy (XPS). Excellent electrical properties of $Al_2O_3$/GaN MIS capacitor were grown at $300^{\circ}C$ process temperature.

• Nuclear Engineering and Technology
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• 제26권4호
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• pp.526-535
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• 1994

KMRR(다목적 연구용원자로) 핵연료의 알루미늄 피복재의 부식거동을 평가하기 위해, 부식 예측치와 노내 부식 실측치의 비교를 통해 유도된 열속인자를 도입한 수정된 Griess 경험식을 유도하였다. KMRR 핵연료의 건전성이 유지되는 부식의 설계기준으로써는 산화층의 박리 방지가 보수적으로 설정되었으며, 산화층의 박리는 산화층에서의 온도차이가 114$^{\circ}C$ 이상에서 일어난다고 보수적으로 가정하였다. KMRR 핵연료의 출력이력을 첫 주기부터 평형주기까지 분석하여, 한계출력이력을 결정하였다. 한계출력이력을 가진 KMRR 핵연료의 부식량 예측계산 결과, 최대 산화층의 두께는 50$\mu\textrm{m}$ 이하였으며, 산화층 박리의 설계기준은 2배의 여유도를 가지고 만족하였다. 따라서, KMRR 핵연료는 피복재의 부식으로 인해 손상되지 않을 것으로 판단된다. 그러나, 수정된 Griess 부식경험식의 KMRR에의 적용 타당성은 KMRR 핵연료의 부식 감시를 통해 추가로 검증될 필요성이 있다.

• 한국재료학회지
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• 제27권6호
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• pp.295-300
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• 2017

Aluminum-oxide($Al_2O_3$) thin films were deposited by electron cyclotron resonance plasma-enhanced atomic layer deposition at room temperature using trimethylaluminum(TMA) as the Al source and $O_2$ plasma as the oxidant. In order to compare our results with those obtained using the conventional thermal ALD method, $Al_2O_3$ films were also deposited with TMA and $H_2O$ as reactants at $280^{\circ}C$. The chemical composition and microstructure of the as-deposited $Al_2O_3$ films were characterized by X-ray diffraction(XRD), X-ray photo-electric spectroscopy(XPS), atomic force microscopy(AFM) and transmission electron microscopy(TEM). Optical properties of the $Al_2O_3$ films were characterized using UV-vis and ellipsometry measurements. Electrical properties were characterized by capacitance-frequency and current-voltage measurements. Using the ECR method, a growth rate of 0.18 nm/cycle was achieved, which is much higher than the growth rate of 0.14 nm/cycle obtained using thermal ALD. Excellent dielectric and insulating properties were demonstrated for both $Al_2O_3$ films.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.350-352
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• 2009

The effect of porosity on the high-cycle fatigue properties of Al-Si-Mg casting aluminum alloys was investigated in this study. Microstructure examination, tensile and high-cycle fatigue test were conducted on both Al-Si-Mg casted (F) and heat-treated (T6) conditions. Porosity characteristics on the fracture surfaces of fatigue-tested samples were examined using SEM and image analysis. The microstructure observation results showed that eutectic Si particles were homogeneously dispersed in the matrix of the Al-Si-Mg casting alloys, but there were porosities formed as cast defects. The high-cycle fatigue results indicated that the fatigue strength of the 356-T6 alloy was higher than that of the 356-F alloys because of the significant reduction in volume fraction of pores by heat treatment. The SEM fractography results showed that porosity affected detrimental effect on the fatigue life: 80% of all tested samples fractured as a result of porosity which acted as the main crack initiation site. It was found that fatigue life decreased as the size of the surface pore increased. A comparison was made between surface pore and inner pore fur its effect on the fatigue behavior. The results showed that the fatigue strength with the inner pores was higher than that of the surface pore.