• 마이크로전자및패키징학회지
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• 제25권1호
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• pp.35-40
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• 2018

Nd:YAG Laser를 이용하여 polyimide film에 탄화(carbonization)를 진행하여 Carbon을 생성하여 저가의 센서를 간단한 제조과정으로 만들었다. 이를 통하여 유연한 저가형 압저항 센서의 특성에 관한 연구를 수행하였다. 기존에 많은 연구들이 Polyimide에 $10.6{\mu}m$의 파장을 가지는 $CO_2$ laser를 이용하여 carbonization을 하여 센서를 제작하였다. 본 논문에서는 polyimide film에 $1.064{\mu}m$의 파장을 가지는Nd:YAG laser를 이용하여 carbonization(탄화공정)을 진행하였다. 또한 Nd:YAG laser를 사용하여 polyimide film위에 직접 탄화시키며 carbon을 생성하는 최적의 전력밀도($W/cm^2$)과 속도(scan rate) 조건 조합을 찾아 해상도를 높였다. $CO_2$ laser를 사용하였던 기존의 선행연구에서는 carbon생성의 최소 선폭이 $140{\sim}220{\mu}m$의 길이를 가졌지만, 본 연구에서는 카본의 생성되는 선폭이 $35{\sim}40{\mu}m$으로 축소시켰다. 이번 연구에서 제작된 센서의 초기 면저항은 $100{\sim}300{\Omega}/{\square}$ 이였다. 곡률 반경 21 R 로 인장을 하였을 때 저항이 30% 줄어들었고, 이를 통하여 계산된 게이지 팩터는 56.6이였다. 본 연구는 압저항 센서를 제조하기 위한 단순하고, 매우 유연하고 저렴한 공정을 제공한다.

• 스마트미디어저널
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• 제12권5호
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• pp.36-45
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• 2023

최근 디지털 농업에 있어서 IoT를 기반으로 한 온실의 종류 및 활용이 확산되고 있으며, 온실의 현대화, 대형화와 스마트 기술을 활용한 공장화까지 진행되고 있다. 그러나 스마트 온실에서의 데이터 수집을 위한 장비와 온실의 크기나 모양과 같은 형태에 따른 구체적 규격화 방안이 제시되지 못하고 있다. 즉, 온실의 규모에 따른 센서와 장비의 종류 및 개수, 작물 및 탄소 중립에 부합하는 온실 시공 필름 종류와 자재 등 시설 설비를 위한 표준 자료가 부족한 실정이다. 따라서 본 연구에서는 데이터 수집을 위한 IoT 장비의 구현, 설치 및 수량의 적합성에대하여 시험하였으며, 데이터 수집과 통신 방식의 구현을 통해 일부 표준기술을 제시하였다. 또한, 기존 온실의 90% 정도를 차지하고 있는 PE, PVC, EVA에 대한 충격강도, 인장, 인열, 신장율, 광투과성 및 수명 문제를 제시하였고, 필름으로 만들어지는 온실의 형태나 규모, 환경적 문제점을 본문에 제시하였다. 본 연구 논문에서는 온실 규모나 농가작물의 형태, 온실 수명 및 필름의 환경적 문제의 해결책으로 나노 소재 필름을 활용한 규격화된 탄소중립 모듈형 스마트 온실을 구현하고 기존 온실과의 성능을 분석·제시하였다. 이를 통해 온실의 규모나 농가작물의 형태에 구분이 없고, 수명이 연장되고 규격화되어 확장 및 축소가 자유로운 묘듈화된 온실을 제안한다. 최종적으로 기존PE, PVC, EVA 필름을 사용한 온실의 평균적 특성과 새로운 탄소중립형 나노 소재를 사용한 온실의 특성을 비교 검토하고, 탄소중립을 지원하는 확장 가능형 IoT 온실의 구현 방안을 제시하고자 한다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.173-179
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• 2000

The friction and wear characteristics of brake friction materials reinforced with aramid fiber, carbon fiber, glass fiber, and potassium titanate whiskers were investigated using a pad-on-disk type friction tester. In particular, the morphology of rubbing surfaces was carefully investigated to correlate the friction performance and properties of transfer films. The aramid fiber reinforced specimen showed severe oscillation of friction coefficient at low speed and low applied pressure. The carbon fiber reinforced specimen showing better friction stability exhibited uniform and stable transfer film than any other specimens. The glass fiber reinforced specimen showed unstable friction changes at high speed and high-applied pressure and the non-uniform transfer film was observed in both friction material and rotor surface. The potassium titanate whiskers reinforced specimen showed stable coherent transfer film. The wear test exhibited the potassium titanate whiskers reinforced specimen was lowest in wear amount and glass fiber reinforced specimen showed the severe wear.

• 한국재료학회지
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• 제19권9호
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• pp.488-493
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• 2009

Thin films of single-wall carbon nanotubes (SWNT) with various thicknesses were fabricated, and their optical and electrical properties were investigated. The SWNTs of various thicknesses were directly coated in the arc-discharge chamber during the synthesis and then thermally and chemically purified. The crystalline quality of the SWNTs was improved by the purification processes as determined by Raman spectroscopy measurements. The resistance of the film is the lowest for the chemically purified SWNTs. The resistance vs. thickness measurements reveal the percolation thickness of the SWNT film to be $\sim$50 nm. Optical absorption coefficient due to Beer-Lambert is estimated to be $7.1{\times}10^{-2}nm^{-1}$. The film thickness for 80% transparency is about 32 nm, and the sheet resistance is 242$\Omega$/sq. The authors also confirmed the relation between electrical conductance and optical conductance with very good reliability by measuring the resistance and transparency measurements.

• 공업화학
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• 제8권1호
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• pp.84-91
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• 1997

대기압하에서 수소를 첨가한 연소염장치를 이용하여 몰리브덴 기판 위에 다이아몬드 필름을 증착시켰다. 기판 온도의 증가에 따라 핵생성밀도가 증가하였으며, $1000^{\circ}C$ 이상에서는 흑연화되고 이것이 수소 원자에 의해 에칭되었다. $C_2H_2/O_2$ 유량비를 증가시킬수록 핵생성밀도는 증가하였지만 결정형태가 구형화되며 비정질카본이 많이 증착되었다. $H_2$를 첨가하면, 표면 활성도가 향상되어 다이아몬드 핵생성밀도가 증가되었으며, 비정질카본을 에칭시켜 우수한 결정성의 다이아몬드 필름을 얻을 수 있었다. 증착시간을 증가시키면 다이아몬드 필름의 두께가 증가하였다.

• 열처리공학회지
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• 제23권2호
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• pp.83-89
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• 2010

Diamond-like carbon (DLC) coating was studied to be a good tribological problem-solver due to its low friction characteristics and high hardness. However, generally hydrogenated DLC film has shown a weak thermal stability above $300^{\circ}C$. However, the silicon doping DLC process by DC pulse plasma enhanced chemical vapor deposition (PECVD) for the new DLC coating which has a good characterization with thermal stability at high temperature itself has been observed. And we were discussed a process for optimizing silicon content to promote a good thermal stability using various tetramethylsilane (TMS) and methane gas at high-temperature. The chemical compositions of silicon-containing DLC film was analyzed using X-ray photoelectron spectroscopy (XPS) before and after heat treatment. Raman spectrum analysis showed the changed structure on the surface after the high-temperature exposure testing. In particular, the hardness of silicon-containing DLC film showed different values before and after the annealing treatment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.93-94
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• 2006

In this research, the enhancement of electron-transfer activity of hemoglobin (Hb) in dodecanoic acid film was investigated for the first time. This type of composite film was made on glassy carbon electrode by casting method. Cyclic voltammetric result of the modified electrode displays a well defined redox peaks which was attributed to the direct electrochemical response of Rb. Our results illustrate that Rb exchange electrons directly with electrode and exhibits the characteristics of peroxidase. When we apply this modified electrode as a biosensor, it gives excellent performances in the electrocatalytic reduction of hydrogen peroxide ($H_{2}O_{2}$). Through the optimal conditions, the proposed biosensor shows the linear range for H2O2 determination was from $1{\times}10^{-5}$ to $1.25{\times}10^{-4}mol/L$ with a detection limit of $1{\times}10^{-7}mol/L$. The biosensor retained more than 90% of the initial response after 14 days.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.469-472
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• 2003

The nematic liquid crystal (NLC) aligning capabilities using a-C:H thin film deposited at the three kinds of rf bias condition were investigated. A high pretilt angle of about $11^{\circ}$ by the ion beam alignment method was observed on the a-C:H thin film (polymer-like carbon) deposited at 1W rf bias condition, and the low pretilt angle of the NLC was observed on the a-C:H thin film(diamond-like carbon) deposited at rf 30W and 60W bias condition. Consequently, the high NLC pretilt angle and the good aligning capabilities of LC alignment by the IB alignment method on the a-C:H thin film deposited at 1W rf bisa condition can be achieved.

• Corrosion Science and Technology
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• 제4권3호
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• pp.75-80
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• 2005

This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 $^{\circ}C$ and 2000~10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperaturewhilethe corrosionrate increasedwith boronconcentration. The experimental resultsobtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightlysolubleboric acid phase.Moreoverthe galvaniccorrosionrate calculatedusing initialgalvaniccoupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor.

• Journal of Information Display
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• 제7권2호
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• pp.22-25
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• 2006

This paper presents heating process for obtaining standing carbon nanotube emitters to improve field-emission properties from the screen-printed multiwalled carbon nanotube (MWCNT) films. In an atmosphere with optimum combination of nitrogen and air for heat treatment of CNT films, the CNT emitters can be made to protrude from the surface. This allows for high emission current and the formation of very uniform emission sites without special surface treatment. The morphological change of the CNT film by this technique has eliminated additional processing steps, such as surface treatment which may result in secondary contamination and damage to the film. Despite its simplicity the process provides high reproducibility in emission current density which makes the films suitable for practical applications.