• 한국표면공학회지
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• 제54권6호
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• pp.365-370
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• 2021

In this research, we proceeded with research on plasma resistance of the cleaning process of APS(Atmospheric Plasma Spray)-Y₂O₃ coated parts used for semiconductor and display plasma process equipment. CF₄, O₂, and Ar mixed gas were used for the plasma environment, and respective alconox, surfactant, and piranha solution was used for the cleaning process. After APS-Y₂O₃ was exposed to CF₄ plasma, the surface changed from Y₂O₃ to YF₃ and a large amount of carbon was deposited. For this reason, the plasma corrosion resistance was lowered and contamination particles were generated. We performed a cleaning process to remove the defect-inducing surface YF₃ layer and carbon layer. Among three cleaning solutions, the piranha cleaning process had the highest detergency and the alconox cleaning process had the lowest detergency. Such results could be confirmed through the etching amount, morphology, composition, and accumulated contamination particle analysis results. Piranha cleaning process showed the highest detergency, but due to the very large thickness reduction, the base metal was exposed and a large number of contaminated particles were generated. In contrast, the surfactant cleaning process exhibit excellent properties in terms of surface detergency, etching amount, and accumulated contamination particle analysis.

• 전기화학회지
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• 제17권1호
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• pp.57-64
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• 2014

다공성의 활성탄소와 상대적으로 입자크기가 더 작은 carbon black을 여러 비율로 혼합하여 다양한 적층배열 구조를 갖는 축전식 탈염용 전극을 제조하였고 활성탄소만 존재하는 전극과 비교 분석하였다. 연구 결과 carbon black의 양이 증가할수록 탄소체의 배열 구조가 조밀해지는 것을 관찰하였고, mesopore가 약 10% 증가하는 것으로 나타났다. 순환전압전류법을 이용하여 축전용량을 살펴보았을 때 carbon black만으로는 이온흡착에 대한 영향이 거의 없지만 활성탄소체와 혼합하여 carbon black의 양이 증가할수록 비축전용량 역시 증가하는 것을 관찰하였다. 최종적으로 셀에 전극을 채용하여 탈염실험을 수행한 결과, carbon black의 양이 가장 많이 함유된 전극의 탈염 성능이 가장 우수하였고, pH의 변화의 폭이 가장 좁았다. 또한, 축전된 전하의 분석을 통해 비페러데이 전류의 비율이 증가하는 것으로 나타나 페러데이 반응에 대한 영향이 감소하는 것을 관찰하였다. 이는 carbon black의 첨가로 전극의 적층배열 구조가 변형함으로써 mesopore의 비율이 증가해 페러데이 반응에 의한 영향이 감소하였고, 탈염 성능 역시 증가하는 것을 알 수 있었다.

• 한국대기환경학회지
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• 제24권5호
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• pp.594-603
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• 2008

A single particle analytical technique, named low-Z particle electron probe X-ray microanalysis, was applied to characterize four samples collected at an underground shopping area connected to Dongdeamun subway station, in January and May 2006. Based on the analysis of their chemical compositions of the samples, many distinctive particle types are identified and the major chemical species are observed to be soil-derived particles, iron-containing particles. sulfates. nitrates, and carbonaceous particles. which are encountered both in coarse and fine fractions. Carbonaceous particles exist in carbon-rich and organic. Soil derived particles such as aluminosilicates, AlSi/C, $CaCO_3\;and\;SiO_2$ are more frequently encountered in spring samples than winter samples. Nitrate- and sulfate-con taming particles are more frequently encountered in winter samples, and those nitrate- and sulfate-containing particles mostly exist in the chemical forms of $Ca(CO_3,\;NO_3),\;Ca(NO_3,\;SO_4),\;(Na,\;Mg)NO_3\;and\;(Mg,\;Na)(NO_3,\;SO_4)$. Fe-containing particles which came from nearby subway platform are in the range of about 10% relative abundances for all the samples. It is observed that nitrate- and sulfate-containing particles and carbonaceous particles are much more frequently encountered in indoor aerosol samples than in outdoor aerosols, implying that $NO_x,\;SO_x$, and VOCs at the underground shopping area were more partitioned into aerosol phase.

• 한국입자에어로졸학회지
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• 제8권4호
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• pp.173-180
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• 2012

SiC particles, 8.3 ${\mu}m$ in volume average diameter, were chlorinated in an alumina tubular reactor, 2.4 cm in diameter and 32 cm in length, with reactor temperature varied from 100 to $1200^{\circ}C$. The flow rate of the gas admitted to the reactor was held constant at 300 cc/min, the mole fraction of chlorine in the gas at 0.1 and the reaction time at 4 h. The chlorination was negligibly small up to the temperature of $500^{\circ}C$. Thereafter, the degree of chlorination increased remarkably with increasing temperature until $900^{\circ}C$. As the temperature was increased further from 900 to $1200^{\circ}C$, the increments in chlorination degree were rather small. At $1200^{\circ}C$, the chlorination has nearly been completed. The surface area of the residual carbon varied with chlorination temperature in a manner similar to that with the variation of chlorination degree with temperature. The surface area at $1200^{\circ}C$ was 912 $m^{2}/g$. A simple model was developed to predict the conversion of a SiC under various conditions. A Langmuir-Hinshelwood type rate law with two rate constants was employed in the model. Assuming that the two rate constants, $k_{1}$ and $k_{2}$, can be expressed as $A_{1e}^{-E_{1}/RT}$ and $A_{2e}^{-E_{2}/RT}$, the four parameters, $A_{1}$, $E_{1}$, $A_{2}$, and $E_{2}$ were determined to be 32.0 m/min, 103,071 J/mol, 2.24 $m^{3}/mol$ and 39,526 J/mol, respectively, through regression to best fit experimental data.

• 에너지공학
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• 제14권4호
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• pp.268-276
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• 2005

액체연료(중유)공급량 기준 20kg/hr규모의 반응로에서 증기분무 내부 혼합식 노즐을 이용하여 잔사유의 연소실험을 수행하였다. 본 실험에서 사용한 감압 잔사유는 점도가 높고 황함량, 잔류탄소와 금속성분의 함량도 높았다. 잔사유의 착화를 위해서는 반응로를 일정온도까지 예열하여야 했으며 이는 LPG를 이용하였다. 잔사유 공급량을 변화시키면서 축방향 및 반경방향의 로내 가스 온도, 주요 가스농도 및 채집된 고체 입자를 분석하였다. 잔사유의 주반응영역은 버너 팁으로부터 약 1 m 근방에서 형성되었으며 이는 축방향 가스 온도, 농도 분포 및 입자의 크기로부터 확인할 수 있었고, 반응로의 하류에서는 완전 확립된 온도분포를 보여주고 있었다. 고체 입자의 SEM 분석으로부터 잔류 탄소입자는 기공이 많은 형태를 띠고 있었다.

• 폴리머
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• 제34권6호
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• pp.534-539
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• 2010

라텍스 블렌딩 기법을 이용하여 폴리스티렌(PS)/다중벽 탄소나노튜브(MWCNT) 나노복합재료를 제조하여 나노튜브 길이에 따른 나노복합재료의 유변학적 특성을 고찰하였다. 나노복합재료 제조에 사용된 단분산 PS 입자는 무유화제 유화중합으로 제조하였고, MWCNT는 불순물 제거와 분산성 향상을 위해 표면개질 과정을 거친 후 사용하였다. 최종적인 나노복합재료는 단분산 PS 입자와 개질한 MWCNT를 초음파 교반조에서 분산시킨 후 동결건조 과정을 거쳐 제조하였다. 나노복합재료의 MWCNT 함량과 나노튜브 길이에 따른 유변학적 특성은 소진폭 진동 전단유동을 부과시켜 평가하였다. 본 연구에서 고찰한 PS/MWCNT 나노복합재료는 MWCNT의 함량이 증가할수록, 나노튜브 길이가 길수록 유변물성 향상 효과가 뚜렷하였다. 이는 MWCNT 함량이 증가할수록 나노복합재료의 유변학적 특성이 액체적 특성에서 점차 고체적 특성으로 변화하기 때문이며, 나노튜브 길이가 길수록 네트워크 구조를 달성하는 임계 농도가 작아지기 때문인 것으로 판단된다.

• 한국입자에어로졸학회지
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• 제9권3호
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• pp.187-197
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• 2013

To understand the characteristics of organic aerosol(OA) at the background atmosphere of Korea, an observation of atmospheric PM10 was conducted at a Global Atmospheric Watch(GAW) station operated by the Korean Meteorological Administration at Anmyon Island during 2010. Various organic compounds were analyzed from 26 samples by using a gas chromatography-mass spectrometer. Water soluble organic carbon(WSOC) was also analyzed by using a total organic carbon(TOC) analyzer. Among 6 classes with 68 target compounds detected, the classes of n-alkanoic and alkenoic acids ($326.67{\pm}75.40ngm^{-3}$) and dicarboxylic acids ($323.74{\pm}361.89ngm^{-3}$) were found to be major compound classes in the atmosphere of Anmyon Island. Compared to the previous results reported for 2005 spring samples at Gosan site, the concentrations of organic compounds at Anmyon Island were 3-10 times higher than Gosan site due to the difference of location and sampling period. The concentrations of organic compounds were varied with the atmospheric conditions. Significant increase of the concentrations of dicarboxylic and carboxylic acids in the smog episode indicated that secondary oxidation of organic compounds was major factor to increase OA concentration during smog episode in the Anmyon Island. It was found that the compositions of the OA measured at Anmyon Island were dependent on the air parcel trajectories.

• 한국수소및신에너지학회논문집
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• 제14권1호
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• pp.24-34
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• 2003

For gaseous fuel combustion with inherent $CO_2$ capture and low NOx emission, chemical-looping combustion may yield great advantages for the savings of energy to $CO_2$ separation and suppressing the effect on environment, In chemical-looping combustor, fuel is oxidized by metal oxide medium in a reduction reactor. Reduced particles are transported to oxidation reactor and oxidized by air and recycled to reduction reactor. The fuel and the air are never mixed, and the gases from reduction reactor, $CO_2$ and $H_2O$, leave the system as separate stream. The $H_2O$ can be easily separated by condensation and pure $CO_2$ is obtained without any loss of energy for separation. In this study, five oxygen carrier particles such as NiO/bentonite, NiO/YSZ, $(NiO+Fe_2O_3)VYSZ$, $NiO/NiAl_2O_4$, and $Co_{\chi}O_y/CoAl_2O_4$ were examined &om the viewpoints of reaction kinetics, oxygen transfer capacity, and carbon deposition characteristics. Among five oxygen particles, NiO/YSZ particle is superior in reaction rate, oxygen carrier capacity, and carbon deposition to other particles. However, at high temperature ($>900^{\circ}C$), NiO/bentonite particle also shows enough reactivity and oxygen carrier capacity to be applied in a practical system.

• 반도체디스플레이기술학회지
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• 제9권1호
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• pp.5-10
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• 2010

Among a variety of cleaning processes, the cryogenic carbon dioxide ($CO_2$) cleaning has merits because it is highly efficient in removing very fine particles, innoxious to humans and does not produce residuals after the cleaning, which enables us to extend its area of coverage in the semi-conductor fabrication society. However, the cryogenic carbon dioxide cleaning method has some technical research issues in aspect to particles' adhesion and removal. To resolve these issues, performing an analysis for the identification of particle adhesion mechanism is needed. In this study, a research was performed by a theoretical approach. To this end, we extended the G-T (Greenwood-Tripp) model by applying the JKR (Johnson-Kendall-Roberts) and Lennard-Jones potential theories and the statistical characteristics of rough surface to investigate and identify the contact, adhesion and deformation mechanisms of soft or hard particles on the rough substrate. The statistical characteristics of the rough surface were taken into account through the employment of the normal probability distribution function of the asperity peaks on the substrate surface. The effects of surface roughness on the pull-off force for these particles were examined and discussed.

• Korean Chemical Engineering Research
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• 제47권3호
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• pp.321-326
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• 2009

간단한 기체농도 측정장치를 제안하여, 혼합기체를 분리하는 흡착공정에서 성능을 실험적으로 조사하였다. 측정센서는 수정진동자의 전극에 고체의 흡착제를 도포하여 유효성분을 선택적으로 분리하게 하여 농도를 측정하였다. 센서용 흡착제는 마이크로 입자의 카본 크라이오젤(Micro-Particle Carbon(MCC))을 사용하였고, 공기와 i-부탄의 혼합기체를 대상으로 대나무 활성탄을 채운 칼럼에서 분리하는 공정을 사용하였다. 칼럼의 입구와 출구에 측정시스템을 각각 장치하고 i-부탄의 농도를 측정하였다. 입구와 출구의 실제농도를 GC로 측정한 결과와 측정한 수정진동자의 공진주파수를 비교하여 제안한 측정시스템이 유용하게 농도를 측정할 수 있음을 보였다. 실험을 통하여 제안하는 시스템이 비교적 간단한 장치로, 실시간 인라인 측정이 가능함을 입증하여 실제공정에 유용하게 활용할 수 있음을 보였다.