• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.225-225
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• 2003

실리카글라스를 기초로 하는 PLC소자는 가격, 광 손실 성질과 광섬유와의 결합효율이 좋아 광통신에 응용되어지고 있으며 Ge 도핑된 실리카 글라스는 PLC소자의 코어물질로 널리 사용되고 있다. 소작제작을 위해서는 높은 식각률과 깨끗하고 적은 표면손상을 얻어야 하므로 유도결합플라즈마를 이용한 건식식각공정개발이 이루어 져야 한다. 본 연구에서는 Ge 도핑된 실리카글라스의 식각특성을 연구하기 위해 $C_2$F/6 와 NF$_3$가스를 사용하였고 ICP power, bias power, 압력, 플라즈마와 샘플간의 거리를 변화시키면서 식각속도, 표면거칠기, 메사수직도, 마스크선택도등 기본공정 조건을 연구하고 첨가가스(CH$_4$, $O_2$), 마스크 물질(Ni, Cr, PR) 도핑농도(0.3, 0.45, 0.7%)등을 변화시키면서 식각특성을 연구하였다. 그 결과 300nm/min, 정도의 식각속도를 가지고 수직한 메사각도(~89$^{\circ}$)와 미려한 표면(표면거 칠기 1.5nm 이하)를 갖는 결과를 얻었다.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.8
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• pp.1194-1201
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• 2015

This study investigated the effect of oxidized soybean oil in the diet of young chickens on growth performance and intestinal oxidative stress, and indices of intestinal immune function. Corn-soybean-based diets containing 2% mixtures of fresh and oxidized soybean oil provided 6 levels (0.15, 1.01, 3.14, 4.95, 7.05, and $8.97meqO_2/kg$) of peroxide value (POV) in the diets. Each dietary treatment, fed for 22 d, had 6 replicates, each containing 30 birds (n = 1,080). Increasing POV levels reduced average daily feed intake (ADFI) of the broilers during d 1 to 10, body weight and average daily gain at d 22 but did not affect overall ADFI. Concentrations of malondialdehyde (MDA) increased in plasma and jejunum as POV increased but total antioxidative capacity (T-AOC) declined in plasma and jejunum. Catalase (CAT) activity declined in plasma and jejunum as did plasma glutathione S-transferase (GST). Effects were apparent at POV exceeding $3.14meqO_2/kg$ for early ADFI and MDA in jejunum, and POV exceeding $1.01meqO_2/kg$ for CAT in plasma and jejunum, GST in plasma and T-AOC in jejunum. Relative jejunal abundance of nuclear factor kappa B ($NF-{\kappa}B$) P50 and $NF-{\kappa}B$ P65 increased as dietary POV increased. Increasing POV levels reduced the jejunal concentrations of secretory immunoglobulin A and cluster of differentiation (CD) 4 and CD8 molecules with differences from controls apparent at dietary POV of 3.14 to $4.95meqO_2/kg$. These findings indicated that growth performance, feed intake, and the local immune system of the small intestine were compromised by oxidative stress when young broilers were fed moderately oxidized soybean oil.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.1
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• pp.17-23
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• 2008

In this study, plasma processing of metal surface is experimentally investigated to enhance the surface decontamination efficiency and to find out the reaction mechanism. Cobalt, the major contaminant in the nuclear facilities, and three fluorine-containing gases, $CF_4/O_2$, $SF_6/O_2$, and $NF_3$ are chosen for the investigation. Thin metallic disk specimens are prepared and their surface etching reactions with the three plasma gases are examined. Results show that the maximum etching rate of $17.2\;{\mu}m/min.$ is obtained with NF3 gas at $420^{\circ}C$, while with $CF_4/O_2$, $SF_6/O_2$ gas plasmas those of $2.56\;{\mu}m/min.$ and $1.14\;{\mu}m/min.$ are obtained, respectively. Along with etching experiments, constituent elements of the reaction products are identified to be cobalt, oxygen, and fluorine by AES (Auger Electron Spectroscopy) analysis. It turns out that the oxygen atoms are physically adsorbed ones to the surface from the ambient not participation ones during the analysis after reaction, which supports that the surface reaction of cobalt is mainly to be a fluorination reaction.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05a
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• pp.59-60
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• 1992

• ETRI Journal
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• v.16 no.1
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• pp.45-57
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• 1994

The effects of reactive ion etching (RIE) of $SiO_2$ layer in $CHF_3/C_2F_6$ on the underlying Si surface have been studied by X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometer, Rutherford backscattering spectroscopy, and high resolution transmission electron microscopy. We found that two distinguishable modified layers are formed by RIE : (i) a uniform residue surface layer of 4 nm thickness composed entirely of carbon, fluorine, oxygen, and hydrogen with 9 different kinds of chemical bonds and (ii) a contaminated silicon layer of about 50 nm thickness with carbon and fluorine atoms without any observable crystalline defects. To search the removal condition of the silicon surface residue, we monitored the changes of surface compositions for the etched silicon after various post treatments as rapid thermal anneal, $O_2$, $NF_3$, $SF_6$, and $Cl_2$ plasma treatments. XPS analysis revealed that $NF_3$ treatment is most effective. With 10 seconds exposure to $NF_3$ plasma, the fluorocarbon residue film decomposes. The remained fluorine completely disappears after the following wet cleaning.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2153-2155
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• 2005

SF6 &NF3 chemistry를 사용하여 W bitline process 조건에서 plasma confinement 및 gas & radical의 flow에 영향을 미치는 focus ring 재질과 두께변경을 하여 Rnit non uniformity 평가한다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1354-1355
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• 2008

교류 펄스전압을 이용한 글라이딩 아크 플라즈마를 이용하여 PFCs(Perfluoro compounds) 가스의 일종인 $CF_4$ $SF_6$, $NF_3$를 가스분해하는 연구를 실시하였다. 반응기 양전극 사이에 인가되는 전압은 10kV로 고정하고 각각의 가스의 유량을 조절하여 분해한후 FT-IR을 통해 각각의 가스의 분해율과 분해후 가스내 성분을 스펙트럼을 이용하여 분석하였다. 유량이 낮아질수록 분해율은 좋아졌고 $SF_6$와 $NF_3$의 경우 99%이상의 높은 분해율에 도달하였을 뿐 아니라 대표적인 난분해 가스로 손꼽히는 $CF_4$의 경우 82%이상의 분해율을 확인하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.95-95
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• 2009

대기압 플라즈마 발생장치를 이용한 식각장비 개발은 낮은 공정단가, 저온 공정, 다양한 표면처리 응용 효과와 같은 이점을 가지고 있어 현재, 많은 분야에서 연구되고 있다. 본 연구에서는, dielectric barrier discharge(DBD) 방식을 이용한 대기압 발생장치를 통해 평판형 디스플레이 제작에 응용이 가능한 $SiO_2$ 층의 식각에 대한 연구를 하였다. $N_2/NF_3$ gas 조합에 $CF_4$ 또는 $C_{4}F_{8}$ gas를 부가적으로 첨가하였다. 이때 N2 60 slm / NF3 600 sccm/CF4 7 slm/Ar 200 sccm의 gas composition에서 최대 260 nm/min의 식각 속도를 얻을 수 있었다.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1096-1106
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• 2018

Purpose: Alzheimer's disease (AD) is the sixth most common cause of death in the United States. MicroRNAs have been identified as vital players in neurodegenerative diseases, including AD. microRNA-128 (miR-128) has been shown to be dysregulated in AD. This study aimed to explore the roles and molecular mechanisms of miR-128 in AD progression. Materials and Methods: Expression patterns of miR-128 and peroxisome proliferator-activated receptor gamma ($PPAR-{\gamma}$) messenger RNA in clinical samples and cells were measured using RT-qPCR assay. $PPAR-{\gamma}$ protein levels were determined by Western blot assay. Cell viability was determined by MTT assay. Cell apoptotic rate was detected by flow cytometry via double-staining of Annexin V-FITC/PI. Caspase 3 and $NF-{\kappa}B$ activity was determined by a Caspase 3 Activity Assay Kit or $NF-{\kappa}B$ p65 Transcription Factor Assay Kit, respectively. Bioinformatics prediction and luciferase reporter assay were used to investigate interactions between miR-128 and $PPAR-{\gamma}$ 3'UTR. Results: MiR-128 expression was upregulated and $PPAR-{\gamma}$ expression was downregulated in plasma from AD patients and $amyloid-{\beta}$ $(A{\beta})-treated$ primary mouse cortical neurons (MCN) and Neuro2a (N2a) cells. Inhibition of miR-128 decreased $A{\beta}-mediated$ cytotoxicity through inactivation of $NF-{\kappa}B$ in MCN and N2a cells. Moreover, $PPAR-{\gamma}$ was a target of miR-128. $PPAR-{\gamma}$ upregulation attenuated $A{\beta}-mediated$ cytotoxicity by inactivating $NF-{\kappa}B$ in MCN and N2a cells. Furthermore, $PPAR-{\gamma}$ downregulation was able to abolish the effect of anti-miR-128 on cytotoxicity and $NF-{\kappa}B$ activity in MCN and N2a cells. Conclusion: MiR-128 inhibitor decreased $A{\beta}-mediated$ cytotoxicity by upregulating $PPAR-{\gamma}$ via inactivation of $NF-{\kappa}B$ in MCN and N2a cells, providing a new potential target in AD treatment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.1-5
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• 2005

A new model of plasma etch process was constructed by using a radial basis function network (RBFN). This technique was applied to an etching of silicon carbide films in a NF$_3$ inductively coupled plasma. Experimental data to train RBFN were systematically collected by means of a 2$^4$ full factorial experiment. Appropriateness of prediction models was tested with test data consisted of 16 experiments not pertaining to the training data. Prediction performance was optimized with variations in three training factors, the number of pattern units, width of radial basis function, and initial weight distribution between the pattern and output layers. The etch responses to model were an etch rate and a surface roughness measured by atomic force microscopy. Optimized models had the root mean-squared errors of 26.1 nm/min and 0.103 nm for the etch rate and surface roughness, respectively. Compared to statistical regression models, RBFN models demonstrated an improvement of more than 20 % and 50 % for the etch rate and surface roughness, respectively. It is therefore expected that RBFN can be effectively used to construct prediction models of plasma processes.