• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3108-3113
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• 2008

This paper investigated the behaviors of combustion characteristics at part load condition with various intake charge motions induced by the port masking schemes in the CVVT (Continuously Variable valve Timing) engine. Time resolved in-cylinder and exhaust emissions were measured by the fast response HC and NOx analyzers to examine their formation mechanisms and behavior characteristics. As a result, in-cylinder HC decreased with the advanced intake valve timings but HC at the exhaust port increased due to the worse combustion stabilities. However HC reduction could be achieved by the application of the port maskings with a enhancement of the engine stability. NOx also decreased with early intake timings by internal EGR but increased with the charge motion controls which enhance the combustion behavior.

• 한국전기전자재료학회논문지
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• 제15권1호
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• pp.7-14
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• 2002

In this paper, neutral networks are used to build models of oxide film etched In CHF$_3$/CF$_4$ with a magnetically enhanced reactive ion etcher(MERIE). A statistical 2$\^$4-1/ experimental design plus one center point was used to characterize relationships between process factors and etch responses. The factors that were varied include radio frequence(rf) power, pressure, CHF$_3$ and CF$_4$ flow rates. Resultant 9 experiments were used to train neural networks and trained networks were subsequently tested on its appropriateness using additionally conducted 8 experiments. A total of 17 experiments were thus conducted for this modeling. The etch responses modeled are dc bias voltage, etch rate and etch uniformity A qualitative, good agreement was obtained between predicted and observed behaviors.

• Journal of Photoscience
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• 제9권3호
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• pp.57-63
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• 2002

A homopolymer containing anthracene groups, poly[6-(9-anthryloxy)hexyl methacrylate] (PAn) was prepared and the effect of oxygen on its photochemical reaction was studied by UV and IR absorption spectroscopy in order to understand its photochemical behavior. Photochemical reaction of the PAn in THF solution under an atmosphere of air resulted in the formation of endoperoxide at the beginning stage of reaction followed by photodimerization reaction after all the oxygen was consumed, whereas photodimerization and endoperoxide formation took place concomitantly in the film state. The photoreversible reaction of the anthracene photodimer groups in the polymer by photolysis with 254 nm UV light was not efficient. The IR absorption spectral changes of the PAn film upon irradiation indicate that various photooxidation products were produced in the atmosphere of air.

• Bulletin of the Korean Chemical Society
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• 제15권12호
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• pp.1050-1054
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• 1994

Eu(Ⅲ) exhibits one electron-transfer reduction at E$_{1/2}$ =-0.617 V vs. Ag/AgCl and the hypersensitive peak at 618 nm corresponding to $^5D_0$ ${\leftrightarro}$ $^7F_2$ transition in 0.10 M LiClO$_4$ aqueous solutions. Upon the addition of carboxylate or sulfonate anions to the Eu(Ⅲ) aqueous solutions, the reduction potential shifts negatively and the reduction current decreases because of the complex formation between Eu(Ⅲ) ions and the anions. However, for the case of carboxylate anion (acetate or propionate) the shift of reduction peak potential and the emission intensity at 618 nm are greater. The results are interpreted in terms of the differences in the formation constants and the hypersensitivity.

• Archives of Metallurgy and Materials
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• 제64권3호
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• pp.913-916
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• 2019

For the reliable applications of silver nanowires, AgNW, which is used as a conductive transparent film in electronic devices, the isothermal degradation behaviors of AgNW films with and without overcoating were investigated. Accelerated isothermal degradation was performed as a function of temperature, time, and atmosphere. Electrical resistance and optical transmittance were measured and correlated with the microstructural damages, such as formation of oxide particles and fragmentations of AgNW, which were quantitatively determined from the scanning electron micrographs. The overcoating retarded the formation of oxide particles and subsequent fragmentations as well as resulting degradation in electrical resistance without affecting the optical transmittance.

• 전기전자학회논문지
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• 제28권3호
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• pp.360-364
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• 2024

Npn heterostructures with GaN collectors were fabricated using nanomembrane (NM) stacking. N- and p-Si NMs were transfer-printed onto the n-GaN substrates, resulting in the formation of vertical n-Si/p-Si/n-GaN heterostructures. Electrical measurements of Si/Si and Si/GaN pn heterostructures exhibited rectifying properties, indicating that the formation of bipolar junctions was feasible through NM stacking. The energy band diagram of stacking-enabled npn heterostructure was analyzed to explain the rectifying behaviors of base-emitter and collector-base junctions, as well as to suggest potential applications for bipolar junction transistors with a GaN subcollector.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.137-138
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• 2002

The benefits of using DLC coatings on steel in dry sliding are well known. The present study has investigated the effects of using the same materials but in a boundary lubricated environment. Tribological tests were performed using a load-scanning device and a lubricant with an extreme-pressure (EP) additive. XPS and grazing incidence XRD are used for chemical analysis. The chemical composition of the resulting tribofilm is correlated to different friction behaviors and contact loads, and indicates that high loads are beneficial for formation of low friction tribofilm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.93.6-93
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• 2002

Many livings form groups that we consider as collective systems. Their collective behaviors are good model for the development of useful distributed systems. In this paper, We discussed the group of motile elements that is described by simple model. The dynamics of each element is described by simple kinematics, but the group shows various types of motions. In addition, we found out the formation of the group changes by modifying rc which is an optimum distance between each element. This modification shows us to observe close-packed structure, face-centered lattice, sim pie lattice and double file.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1257-1258
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• 2006

Biomimetic apatite deposition behaviors and mechanical performance for as-rolled and annealed Ni-Ti plates were investigated . A good biomimetic apatite formation and excellent mechanical performance of Ni-Ti suggests that Ni-Ti can be an excellent candidate material as orthopedic implants.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
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• pp.129.2-129
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• 2003