• 한국재료학회지
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• 제2권1호
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• pp.76-82
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• 1992

$TEOS-O_3$ 산화막은 깔개층 물질에 따라 증착속도가 변하는 특성을 나타낸다. 본 논문에서는 $TEOS-O_3$ 산화막의 깔개층 물질 의존성 이외에도 배선 밀도, 배선 간격에 따라 증착속도가 달라지는 패턴 의존성에 대하여 조사하였다. 또한 $TEOS-O_3$ 산화막의 깔개층 물질 의존성 및 패턴 의존성을 줄이기 위해 다층 배선에서 1차 배선후에 깔개층, 즉 TEOS-base 프라즈마 산화막 및 $SiH_4-base$ 프라즈마 산화막을 증착했을 때 $TEOS-O_3$ 산화막의 증착 특성을 조사하였다. 그리고 그 깔개층 물질에 $N_2$ 프라즈마 처리를 했을 때 $TEOS-O_3$ 산화막의 증착 특성에 대해 조사하였다. 그 결과 $TEOS-O_3$ 산화막에서 기판 위에 배선 밀도와 배선 간격에 따른 의존성은 깔개층물질이 $SiH_4-base$ 일때보다 TEOS-base 프라즈마 산화막인 경우 $N_2$ 프라즈마 처리를 하면 깔개층 물질 표면이 O-Si-N화 되므로써 의존성이 사라지게 된다.

• 폴리머
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• 제29권2호
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• pp.151-155
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• 2005

카본블랙의 산-염기 표면처리에 따른 카본블랙/고무 복합재료의 기계적 물성에 대해 고찰하였다. 산-염기 표면처리에 의한 카본블랙 표면특성은 pH,표면 산${\cdot}$염기도와 표면자유에너지를 통해 알아보았으며, 카본블랙/고무 복합재료의 기계적 물성은 가교밀도$(V_e)$와 인열에너지(T) 등을 통해 살펴보았다. 카본블랙을 산성용액으로 처리한 경우는 표면자유에너지의 극성 요소$({\gamma}s^{sp})$증가로, 카본블랙/고무 복합재료의 기계적 물성이 감소하였다. 반면에, 염기성 용액으로 처리한 경우는 산성 용액으로 처리한 경우 또는 표면처리를 시행하지 않은 경우보다 표면자유에너지의 비극성 요소$({\gamma}s^L)$ 증가와 충전제-고무의 상호작용 증가로 인하여 카본블랙/EPDM 복합재료의 가교밀도와 기계적 물성이 증가하였다. 이를 통해 산-염기 표면처리에 의한 카본블랙의 표면특성이 고무 매트릭스 복합재료의 물리적 거동에 중요한 인자로 작용함을 확인하였다.

• Composites Research
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• 제30권1호
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• pp.41-45
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• 2017

Magnetite nanoparticles were synthesized by adding an ammonium hydroxide to a mixed solution of iron (II) and (III) chlorides. A silicon surfactant of ${\alpha},{\omega}$-(3-aminopropyl)polydimethylsiloxane was adsorbed on the particles as dispersant and a polydimethylsiloxane polymer was used to prepare ferrofluids of silicone oil base. Fluorinated surfactants of anionic ammoniated perfluoroalkyl sulfonamide and nonionic fluoroaliphatic polymeric esters were applied to the particles and a perfluoropolyether was used to prepare ferrofluids of fluorine oil base. The experimental conditions were used for preparing the ferrofluids with concentrations of 200, 300 and 400 mg/mL, and density, magnetization and viscosity of the products were characterized. The density values increased in proportion to the concentration, indicating 1.11-1.27 g/mL for silicone-oil-based fluids and 1.95-2.10 g/mL for fluorine-oil-based fluids in the range of 200-400 mg/mL. The saturation magnetization of the silicone-oil-based and fluorine-oil-based fluids indicated 14.7, 24.4, and 30.7 mT and 15.8, 23.3, and 33.7 mT for 200, 300, and 400 mg/mL, respectively, depending on the content of magnetic particles in the fluid. The viscosity of the silicone-oil-based ferrofluids was highly stable compared to that of the fluorine-oil-based with increasing temperatures. The ferrofluids are usually applied to seals and speakers with the silicone base and to seals with the fluorine base.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.51-54
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• 2003

Three kinds of experiments were conducted to test existing methods and develop an effective methodology for the remediation of DNAPL trapped in vertical dead-end fractures. A water-flushing method failed to remove TCE from vertical dead-end fractures where no fluid flow occurs. A water-flushing experiment implies that existing remediation methods, utilizing water-based remedial fluid such as surfactant-enhanced method, have difficulty in removing DNAPL trapped from the vertical downward dead-end fractures, because of no water flow through dead-end fractures, capillary, and gravity forces. Fluid denser than TCE was injected into the fracture network, but did not displace TCE from the vertical dead-end fractures. Base(B on the analysis of the experiments, the increase in the density of the dense fluid and the addition of surfactant to the dense fluid were suggested, and this composite dense fluid with surfactant effectively removed TCE from the vertical dead-end fractures.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2286-2291
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• 2008

Some electronics component, which is adopted as components of antenna for radar or satellite system and used for amplifying signals to transmit, is accompanied by very significant heat dissipation levels because of the inefficiencies inherent in radio frequency wave generation. So, proper cooling performance for that system is base requirement for thermal design. On this paper, we applied heat spreading structures to reduce thermal density and find the optimum values of heat sink design factors through theoretically, numerically and evaluated by product test. As the results, the performance of the cooling system shows the propriety of cooling high density heat dissipation electronics components.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.799-800
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• 2006

Wrought Si-steels are generally used for electromagnetic valves, which are needed good response. To date, Hitachi Powdered Metals Co., Ltd. have produced Fe-Si base sintered magnetic material, EU-52, which shows a magnetic flux density of more than 1.25T at 2000A/m and a maximum permeability of more than 3500. However these magnetic properties are lower than that of wrought Si-steels. Because EU-52 has a low density of $7.2Mg/m^3$. For improving the magnetic properties, it is necessary to increase the density of sintered cores. To increase density, a new mixing method of coating fine Si powders on atomized iron powders was developed, for avoiding the Kirkendall effect. As the result, developed P/M Fe-Si magnetic cores shows higher density of $7.38Mg/m^3$, higher magnetic flux density of 1.48T at 2000A/m and higher maximum permeability of 6800.

• Corrosion Science and Technology
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• 제21권1호
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• pp.32-40
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• 2022

The o-Vanillin - Glutamine Schiff base [2-Hydroxy-3-Methoxy BenzylidineCarbomyl) -2-Butanoic Acid] was examined for low carbon steel corrosion inhibition in acid media. Weight loss studies were carried out at three different temperatures to determine the inhibition efficiency (IE). Electrochemical impedance spectroscopy revealed that the charge transfer resistance controlled the corrosion reaction and Tafel polarization indicated that the Schiff base acts as mixed mode of inhibitor. SEM images were recorded for the surface morphology of the low carbon steel surface. DFT studies revealed corrosion control mechanisms using quantum chemical parameters such as E_HOMO, E_LUMO, energy gap (∆E), chemical Hardness (η), chemical Softness (σ), Electronegativity (χ), and the fraction of electron transferred (∆N), which is calculated using Gaussian software 09. The gas-phase geometry was fully optimized in the Density Functional Theory (DFT/B3LYP-6-31G (d)).The DFT results are in good agreement with the experimental results. All the results proved that the Schiff Base (2-Hydroxy-3-Metoxy BenzylidineCarbomyl) -2-Butanoic is a suitable alternative for corrosion inhibition of low carbon steel in acid media.

• 한국농공학회논문집
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• 제60권6호
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• pp.111-119
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• 2018

The air-void is known to be one of the influencing factors for estimating long-term performance of asphalt concrete. Most of all, confirming air void or density of pavement layer is important for quality control of field compaction level of asphalt concrete pavement. In this study, a non-nuclear type non-destructive density gage (NDDG) was used to estimate compacted air-voids of asphalt pavement as a non-destructive test method. Asphalt concrete slab specimens were prepared using 6 types of asphalt mixes in laboratory (lab) for lab NDDG test. Four different base structure materials were used to find out if there were any differences due to the type of base structure materials. The actual air-voids and NDDG air-voids were measured from 6 asphalt concrete slabs. Four sections of field asphalt pavements were tested using the NDDG, and actual air voids were also measured from field cores taken from the site where the NDDG air-void was measured. From lab and field experimental tests, it was found that the air-voids obtained by NDDG were not the same as the actual air-voids measured from the asphalt concrete specimen. However, it was possible to estimate air voids based on the relationship obtained from regression analysis between actual and NDDG air voids. The predicted air-voids based on the NDDG air-voids obtained from 50mm depth were found to be reliable levels with $R^2{\fallingdotseq}0.9$. Therefore, it was concluded that the air-voids obtained from NDDG could be used to estimate actual air-voids in the field asphalt pavement with a relatively high coefficient of determination.

• 한국산학기술학회논문지
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• 제14권10호
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• pp.4747-4752
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• 2013

MR 유체의 물리적 특성은 자기장에 의해 영향을 받으며, 베이스 오일에 마이크로 크기의 자성 파우더가 분산되어 있다. 그러므로 오일과 파우더의 밀도 차이로 MR 댐퍼에 사용되는 MR 유체의 분산 안정성은 중요한 문제이다. 본 실험연구에서는 MR 댐퍼에 사용되는 MR 유체의 화학적 조성에 따른 물리적 특성을 규명해보고자 MR 유체를 제조하여 분산 안정성과 물리적 특성을 조사하였다. 216종의 MR 유체는 자성파우더(2종), 계면활성제(2종), 베이스오일(2종), 특성첨가제(3종), 밀도(3종), 점도(3종)을 이용하여 제조되었다. 실험결과로부터 SEM, 자속밀도, MR 유체의 상등액과 침강층의 분산 자료를 확보하였다.

• 펄프종이기술
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• 제37권5호통권113호
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• pp.70-77
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• 2005

The development of printable Hanji is regarded as an important work to create a new demand of Hanji in information-oriented era. Hanji has rougher surface, huger absorption of ink and lower optical properties and printabilities than common printing papers. Improving those shortcomings of Hanji is required to be printable Hanji. Sizing and calendering have known as a way to make properties of paper good. Accordingly, this research was performed to find out useful sizing agents for reforming its drawbacks. Four sizing agents (CMC, com starch, PVA, AKD) were used in this research. The optical properties and the printabilities of sized Hanji were tested. The obtained results were as follows. Based on concentration, each sizing agent was prepared. These were CMC(0.5, 1, $1.5\%$), corn starch(1, 2, $3\%$), PVA(1, 5, $10\%$), AKD(0.5, 0.1, $0.15\%$) respectively. After sizing, we performed calendering treatment with pressure of 0.5, $1\;kgf/cm^2$. All the sizing agents and calendering treatment improved the properties of Hanji to some extent. Particularly, com starch was good for gloss. In case of printability, $1\%$ AKD with $1\;kgf/cm^2$ was recommendable for typography ink density, $3\%$ com starch with $0.5\;kgf/cm^2$, inkjet ink density, $2\%$ com starch with $0.5\;kgf/cm^2$, inkjet ink girth. PVA and AKD without calendering were counter-effective agents for inkjet ink density. Printable Hanji is required to have not only better surface strength enough to appear non-picking, higher ink density and lower show-through than base paper but also the lowest ink girth in comparison with base paper. When referring to them, efficient sizing agents were regarded as $0.1\%$ AKD with $1\;kgf/cm^2$, calender pressure, for typography printing and $2\%$ com starch with $0.5\;kgf/cm^2$, calender pressure, for inkjet printing.