• 한국표면공학회지
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• 제54권6호
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• pp.340-347
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• 2021

Among various metal oxide semiconductors, ZnO has an excellent electrical, optical properties with a wide bandgap of 3.3 eV. It can be applied as a photocatalytic material due to its high absorption rate along with physical and chemical stability to UV light. In addition, it is important to control the morphology of ZnO because the size and shape of the ZnO make difference in physical properties. In this paper, we demonstrate synthesis of size-controlled ZnO tetrapods using an atmospheric pressure plasma system. A micro-sized Zn spherical powder was continuously introduced in the plume of the atmospheric plasma jet ignited with mixture of oxygen and nitrogen. The effect of plasma power and collection sites on ZnO nanostructure was investigated. After the plasma discharge for 10 min, the produced materials deposited inside the 60-cm-long quartz tube were obtained with respect to the distance from the plume. According to the SEM analysis, all the synthesized nanoparticles were found to be ZnO tetrapods ranging from 100 to 600-nm-diameter depending on both applied power and collection site. The photocatalytic efficiency was evaluated by color change of methylene blue solution using UV-Vis spectroscopy. The photocatalytic activity increased with the increase of (101) and (100) plane in ZnO tetrapods, which is caused by enhanced chemical effects of plasma process.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.95-102
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• 2022

Since the organic light-emitting diodes (OLEDs) have been widely investigated as next-generation displays, it has been successfully commercialized as a flexible and rollable display. However, there is still wide room and demand to improve the device characteristics such as power efficiency and lifetime. To solve this issue, there has been a wide research effort, and among them, the internal and the external light extraction techniques have been attracted in this research field by its fascinating characteristic of material independence. In this study, a micro-nano composite structured external light extraction layer was demonstrated. A reactive ion etching (RIE) process was performed on the surfaces of hexagonally packed hemisphere micro-lens array (MLA) and randomly distributed sphere diffusing films to form micro-nano composite structures. Random nanostructures of different sizes were fabricated by controlling the processing time of the O₂ / CHF₃ plasma. The fabricated device using a micro-nano composite external light extraction layer showed 1.38X improved external quantum efficiency compared to the reference device. The results prove that the external light extraction efficiency is improved by applying the micro-nano composite structure on conventional MLA fabricated through a simple process.

• 농촌의학ㆍ지역보건
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• 제8권1호
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• pp.19-27
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• 1983

살충제(殺蟲劑)의 주종(主宗)을 이루는 유기인제(有機憐劑)에 의한 만성중독(慢性中毒)의 예방(豫防)을 위(爲)한 기초자료(基礎資料)를 얻고, 또한 농업종사자(農業從事者)의 혈장(血漿) cholinesterase의 정상치(正常植)를 추정(推定)하고저 전라북도(全羅北道) 정읍군(井邑郡)의 일부(一部) 농업종사자(農業從事者)에 대(對)한 혈장(血漿) cholinesterase 치(植)를 Takahashi의 Micro- method로 측정분석(測定分析)한바 다음과 같이 요약(要約)된다. 1) 농약살포전군(農藥澈布前群)의 혈장(血漿) cholinesterase 치(植)는 $7.60{\pm}1.74{\mu}M/20{\mu}{\ell}$/hr.였고, 살포후군(撒布後群)에서는 $6.23{\pm}1.59{\mu}/20{\mu}{\ell}$/hr.로서 살포전군(澈布前群)보다 $1.37{\mu}M/20{\mu}{\ell}$/hr.가 낮게 나타났다 (P < 0.01). 2) 농업종사자(農業從事者)의 정상(正常) 혈장(血漿) cholinesterase 치(植)의 95% 신뢰구간(信賴區間)은 $7.30-7.90{\mu}M/20{\mu}{\ell}$/hr.이었다.

• Tuberculosis and Respiratory Diseases
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• 제71권1호
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• pp.8-14
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• 2011

Background: MicroRNAs (miRNAs) have demonstrated their potential as biomarkers for lung cancer diagnosis. In recent years, miRNAs have been found in body fluids such as serum, plasma, urine and saliva. Circulating miRNAs are highly stable and resistant to RNase activity along with, extreme pH and temperatures in serum and plasma. In this study, we investigated serum miRNA profiles that can be used as a diagnostic biomarker of non-small cell lung cancer (NSCLC). Methods: We compared the expression profile of miRNAs in the plasma of patients diagnosed with lung cancer using an miRNA microarray. The data from this assay were validated by quantitative real-time PCR (qRT-PCR). Results: Six miRNAs were overexpressed and three miRNAs were underexpressed in both tissue and serum from squamous cell carcinoma (SCC) patients. Sixteen miRNAs were overexpressed and twenty two miRNAs were underexpressed in both tissue and serum from adenocarcinoma (AC) patients. Of the four miRNAs chosen for qRT-PCR analysis, the expression of miR-23a was consistent with microarray results from AC patients. Receiver operating characteristic (ROC) curve analyses were done and revealed that the level of serum miR-23a was a potential marker for discriminating AC patients from chronic obstructive pulmonary disease (COPD) patients. Conclusion: Although a small number of patients were examined, the results from our study suggest that serum miR-23a can be used in the diagnosis of AC.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권5호
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• pp.215-219
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• 2004

The effects of ambient temperature on the discharge characteristics of Ne-Xe based micro discharge cells for ac-PDP (plasma display panel) have been studied. In ramp voltage driving, which is generally used as a reset method of PDP, two dissimilar modes of strong and weak discharge were found. As the interval between the former sustaining discharge and ramp voltage discharge becomes greater, the probability of a strong discharge increases. This suggests that a sufficient number of priming particles is necessary for initiating weak mode (Townsend discharge). It was discovered that under higher ambient temperatures, weak discharge occurs more frequently. The discharge time lag observed in square pulse driving of single cells becomes surprisingly smaller under higher ambient temperatures for the constant gas number density condition.

• E2M - 전기 전자와 첨단 소재
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• 제9권5호
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• pp.470-475
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• 1996

Fiber-textured diamond films have been deposited on scratched silicon(100) substrate by micro wave .plasma enhanced chemical vapor deposition at the condition of micro wave power : 950 W, pressure : 60 torr, H$_{2}$ gas flow rate : 50 sccm, CH$_{4}$ gas flow rate : 1.5 sccm, substrate temperature : about 900.deg. C and deposition time : 20 hours. The films were characterized by mean of scanning electron microscopy, Raman spectroscopy and X-ray analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.917-920
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• 2006

In an attempt to reduce processing cost and to improve resolution of PDPs, micro mold transfer processing route for barrier ribs of plasma display panel was developed. In this study, the parameters that may cause defects during the process were identified, which include the shrinkage during UV curing process, stress due to evaporation of organic components, and sintering shrinkage. Considering such parameters, UV curable paste was developed and barrier ribs of PDPs were successfully processed via the process. In addition, the process was successfully applied for the processing of barrier ribs with embedded counter electrodes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1991-1993
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• 2002

This paper presents the PDMS surface characteristic change after the plasma process and the electroosmotic flow control technique for the two-dimensional focusing in the micro channels made of PDMS and glass. The channels are fabricated by plastic molding and micromachining technique. To observe the surface characteristic change as time elapses, we measure the contact angle of water on the surface and the velocity of the electroosmotic flow in a channel. The electric field adequate for focusing of a core flow in a confluence channel is obtained by the experiment. The computer simulation is performed to obtain the width and the depth of the core flow for several junction angles of the confluence channel.

• Journal of Microbiology and Biotechnology
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• 제17권9호
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• pp.1573-1578
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• 2007

An increasing number of applications is being developed for the use of nanoparticles in various fields. We investigated possible toxicities of nanoparticles in cell culture and in mice. Nanoparticles tested were Zn (300 nm), Fe (100 nm), and Si (10-20, 40-50, and 90-110 nm). The cell lines used were brain, liver, stomach, and lung from humans. In the presence of nanopaticles, mitochodrial activity decreased zero to 15%. DNA contents decreased zero to 20%, and glutathione production increased zero to 15%. None of them showed a dose dependency. Plasma membrane permeability was not altered by nanoparticles. In the case of Si, different sizes of the nanoparticles did not affect cytotoxicity. The cytotoxicity was also shown to be similar in the presence of micro-sized ($45\;{\mu}m$) Si particles. Organs from mice fed with nanoparticles showed nonspecific hemorrhage, lymphocytic infiltration, and medullary congestion. A treatment with the micro-sized particle showed similar results, suggesting that the acute in vivo toxicity was not altered by nano-sized particles.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.490-490
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• 2012

Ballast capacitor에 저장된 에너지로 방전 에너지를 조절할 수 있는 방전장치를 개발하였다. 본 연구에서는 ballast capacitor의 용량을 조절하여 micro-size의 아크 플라즈마를 발생시켰으며, 용량변화에 따른 플라즈마의 온도를 측정하였다. 또한 ICCD camera를 이용하여 ballast capacitor의 용량변화에 따른 cathode의 변화를 관찰하였다. Optical Emission Spectroscopy를 통하여 플라즈마의 광학적 특성을 분석하였다. 마이크로 아크 방전의 주파수를 높이기 위하여 switching device를 병렬로 연결하여 아크 플라즈마를 구동시켰으며, 발생된 마이크로 아크 플라즈마는 정밀방전 가공에 응용되었다. 본 연구는 2011년도 지식경제부의 재원으로 한국에너지 기술평가원(KETEP)의 지원을 받아 수행한 연구 과제입니다(No. 20104010100670).