• Toxicological Research
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• 제17권
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• pp.329-333
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• 2001

Apoptosis is the normal physiological process of cell death essential for the maintenance of homeostasis. The function of nicotinamide adenine dinucleotide (NAD) and adenine diphosphate (ADP) ribosylation (transfer of ADP-ribose to proteins) reactions in modifying apoptosis have recently been of great interest. Recently. CD38. a type 2 transmembrane glycoprotein expressed in hematopoietic and non hematopoietic cell lines. has been reported to possess NAD glycohydrolase activity (Han. 1999) and PC-1 and CD38 NADase regulates T cells by inhibition of phosphodiesterase/pyrophosphatase activity of PC-1 by its association with glycosaminoglycan (Hozada et al., 1999). Sindhuphak et al. (2000) has reported that cervical cancer cells can be differentiated from normal cells by using FTIR (Fourier-Transformed Infrared) technique. which has characterized shifts to be due to the phosphodiester bond in nucleic acid. protein amide I&II. carbohydrate and glycogen bands. Mechanisms how phosphodiester bond shift in cervical cancer cells as compared to control cells remain to be elucidated. Suramana et al. (2000) as well as Lohitnavy and Sinhaseni (1998) have studied methomyl and colchicine effects in rat splenocytes. Lactate Dehydroge-nase Isozymes 3 (LDH3) and LDH4 were observed to increase transiently and subsided in plasma of rats exposed to 6~8 mg/kg methomyl after 48 hours. Phosphodiester bond shift of nucleic acid. detected by FTIR. was also reported (Suramana et al., 2000). We report here, after analysis of bond shift patterns. a similar bond shifts detected by FTIR spectrum observed in human cervical cells and splenocytes of rats exposed orally to 2~8 mg/kg methomyl as well as rats exposed to colchicine 2~6 mg/kg orally.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.140-141
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• 2021

Arc thermal spray process is widely used to protect the steel from corrosion and abrasion. In the present study, two different coatings i.e. Al and Al-5%Mg were used to compare their corrosion resistance performance and the effect of 5% Mg addition in the properties of deposited coating. The SEM results showed the more compact and less porous morphology of Al-5%Mg coating compared to Al. The corrosion resistance performance of both deposited coatings was studied in artificial ocean water with exposure periods and results are compared. The total impedance values of Al-5%Mg at 0.01 Hz exhibited highest with exposure periods might be attributed to the coating and corrosion products nature and morphology compared to Al coating.

• 대한치과기공학회지
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• 제34권2호
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• pp.67-73
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• 2012

연구 목적: 임플란트의 하부구조를 상부 구조와 연결하는 레진시멘트의 접착강도를 높이기 위한 기계적 화학적인 표면처리 방법들이 연구 되고 있다. 이 연구에서 다양한 크기의 $Al_2O_3$ sandblasting과 Silano Pen으로 표면처리한 티타늄과 레진 시멘트의 접착강도를 알아보고자 한다. 연구 방법: 12개의 티타늄(Ti-6A1-4V)시편을 디스크 형태로 제작하여 자가중합 수지에 매립하였다. 이들을 각각 6개의 군으로 나누어 $50{\mu}m$, $90{\mu}m$, $110{\mu}m$ 등 3가지 크기의 $Al_2O_3$로 sandblasting 하는 조건과 $Al_2O_3$로 sandblasting한 후 Silano Pen(Bredent, bredent GmbH &Co.KG, Senden, Germany)을 사용한 군으로 나누었다. 표면처리 한 티타늄 표면에 레진시멘트(Duolink dual syringe, Bisco, USA)으로 접착하였다. 그 후 증류수($37^{\circ}C$)에 24시간 보관 후 접착강도 실험을 시행하였고, SEM을 사용하여 표면처리 한 표면과 접착강도 실험 후 파절양상을 관찰하였다. 결과: 통계학적 분석에 따르면 Silano Pen을 사용하여 표면처리한 군들의 접착강도가 높았다(P<0.05). 결론: Silano Pen을 사용하는 것이 티타늄과 레진시멘트의 접착강도를 증가 시킨다.

• Transactions on Electrical and Electronic Materials
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• 제15권4호
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• pp.221-225
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• 2014

Although gold wire bonding techniques have already matured in semiconductor manufacturing, weakly bonded wires in semiconductor chip assembly can jeopardize the reliability of the final product. In this paper, weakly bonded or failed aluminum bonding pads are analyzed using X-ray photoelectron spectroscopy (XPS), Auger electron Spectroscopy (AES), and energy dispersive X-ray analysis (EDX) to investigate potential contaminants on the bond pad. We found the source of contaminants is related to the dry etching process in the previous manufacturing step, and fluorocarbon plasma etching of a passivation layer showed meaningful evidence of the formation of fluorinated by-products of $AlF_x$ on the bond pads. Surface analysis of the contaminated aluminum layer revealed the presence of fluorinated compounds $AlOF_x$, $Al(OF)_x$, $Al(OH)_x$, and $CF_x$.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.45-47
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• 2006

The rotating components in the hot sections of land-based gas turbine are exposed to severe environments during several tens thousand operation hours at above $1100^{\circ}C$ operation temperature. To protect such components from high temperature oxidation, an intermediate bond coat is applied, typical of a MCrAlY-type metal alloy. This study is concerned with the thermal cyclic behavior of thermal barrier coatings. The MCrAlY bond coatings are deposited by HVOF (High Velocity Oxygen Fuel) method on a nickel-based superalloy (GTD-111). Thermal cyclic tests at $1100^{\circ}C$ in ambient air for various periods of time were used to evaluate the thermal cyclic resistance of the TBC coating. The microstructure and morphology of as-sprayed and of thermal cycled coatings were characterized by scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.180-181
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• 2022

The higher the addition rate, the less difference in kneading was found. This is because most of the cases are mixed with vinyl gloves by hand when immediately mixed in the field, so there is no problem of mixing dough according to the amount of addition. The mean increase temperature for 20 minutes was 31.6℃ for Plain, 38.1℃ for Al, 33.7℃ for Cu, and 5~7℃ for Al 20% added sample, 38.1℃ for Al 20% added sample, but 36.6℃ for Al 5% added sample. This suggests that it is possible to improve its own heat transferability by adding metal powder to epoxy adhesives.

• Structural Engineering and Mechanics
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• 제16권4호
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• pp.469-478
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• 2003

The primary aim of this study was to investigate the bond strength between reinforcement and concrete. Large sized nine beams, which were produced from concrete with approximately ${f_c}^{\prime}=30$ MPa, were tested. Each beam was designed to include two bars in tension, spliced at the center of the span. The splice length was selected so that bars would fail in bond, splitting the concrete cover in the splice region, before reaching the yield point. In all experiments, the variable used was the reinforcing bar diameter. In the experiments, beam specimens were loaded in positive bending with the splice in a constant moment region. In consequence, as the bar diameter increased, bond strength and ductility reduced but, however, the stiffnesses of the beams (resistance to deflection) increased. Morever, a empirical equation was obtained to calculate the bond strength of reinforcement and this equation was compared with Orangun et al. (1977) and Esfahani and Rangan (1998). There was a good agreement between the values computed from the predictive equation and those computed from equations of Orangun et al. (1977) and Esfahani and Rangan (1998).

• 소성∙가공
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• 제27권5호
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• pp.267-275
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• 2018

The clad sheet material is produced by a roll-bonding process of one or more materials with different properties. Good formability of clad sheet material is an essential property in to deform a clad metal sheet into a part or component. Performance of the clad sheet material largely depends on interfacial bond strength between different materials. In this study, interfacial bond strength of STS/Al clad sheet was analyzed by varying experimental parameters using a blanking process. Experimental parameters are the punching speed, clearance, and stacking order of plate materials. In addition, blanking test results were compared with bond strengths measured by the T-peel test, that analyzes interface bonding strength of the standard clad sheet. The blanking process was analyzed by the finite element method under the sticking condition of interface of different materials, and experimental results and analysis results were compared.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1997년도 특별강연 및 추계학술발표 개요집
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• pp.125-127
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• 1997

• 대한기계학회논문집A
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• 제26권11호
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• pp.2374-2382
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• 2002

Aluminum alloy/aramid fiber reinforced plastic(Al/AFRP) laminates consists of high strength metal(A15052) and laminated aramid fiber with structural adhesive bond. The mixture ratio effect of epoxy resin curing agent accelerator on the tensile strength and T-peel strength characteristic in Al AFRP laminates were investigated in this study. The epoxy. diglycidylether of bisphenol A(DCEBA), It'as cured by methylene dianiline(MDA) with or without an accelerator(K-54). Eight different kinds of resin mixture ratios were selected for the test , five kinds of Al/AFRP laminates were named as Al/AFRP(1) and three others of Al/AFRP laminates were named as Al/AFRP(2). The comparison of tensile strength and T-peel strength with variation of resin mixture ratio were studied. Respectively. Al/AFRP(1) and Al/AFRP(2) indicated approximately 6.0 times and 7.0 times more improved maximum tensile strength in comparison with those of monolithic A15052. Al/AFRP(2) indicated approximately 1.5 times more impoved maximum T-peel strengths in comparison with those of Al/AFRP(1). As results. Al/AFRP(2) turned out to have more effective characteristics on the tensile strength and T-peel strength than those of Al/AFRP(1).