• 방사성폐기물학회지
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• 제17권1호
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• pp.15-28
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• 2019

고리 1호기는 원전해체 계획에 따라 영구정지 이후 가능한 한 빠른 시일 내에 원자로냉각재계통의 화학제염을 수행할 계획으로, 계통제염 기술 확보를 위해 한수원에서는 2014년부터 '원전 해체설계를 위한 냉각재계통 및 기기제염 상용기술개발' 연구과제를 통해 화학제염기술을 개발하고 있다. 본 연구를 위해 Lab. 규모 계통제염 공정장치를 제작하였으며, 계통제염 대상의 주요재료인 STS304, 316, 410, Alloy600, SA508을 사용하여 화학제염 공정실험을 수행하였다. 화학제염 공정실험의 목적은 산화-환원공정의 최적시간, 최적제염제 및 공정횟수를 도출하기 위함이다. 화학제염 공정실험은 과망간산-옥살산 기반의 단위공정 및 연속공정 실험, 과망간산+질산-옥살산 기반의 연속공정 실험으로 나누어 수행하였다. 그 결과 단위공정실험을 통해 최적공정 시간인 산화공정 5시간, 환원공정 4시간을 도출하였으며, 연속공정실험을 통해 최적제염제와 공정횟수를 도출하였다. 최적제염제는 산화제의 경우 $200mg{\cdot}L^{-1}$ 과망간산 + $200mg{\cdot}L^{-1}$ 질산이고, 환원제는 $2000mg{\cdot}L^{-1}$ 옥살산이며, 공정횟수는 STS304와 SA508의 경우 2 cycle, Alloy600의 경우 3 cycle 이상 수행하는 것이 적절할 것으로 평가되었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.19.2-19.2
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• 2010

Printed electronics using printing process has broadened in all respects such as electrics (lighting, batteries, solar cells etc) as well as electronics (OLED, LCD, E-paper, transistor etc). Copper is considered to be a promising alternative to silver for printed electronics, due to very high conductivity at a low price. However, Copper is easily oxidized, and its oxide is non-conductive. This is the highest hurdle for making copper inks, since the heat and humidity that occurs during ink making and printing simply accelerates the oxidation process. A variety of chemical treatments including organic capping agents and metallic coating have been used to slow this oxidation. We have established synthetic conditions of copper nanoparticles (CuNPs) which are resistant to oxidation and average diameter of 20 to 50nm. Specific resistivity should be less than $4\;{\mu}{\Omega}{\cdot}cm$ when sintered at lower temperature than $250^{\circ}C$ to be able to apply to conductive patterns of FPCBs using ink-jet printing. Through this study, the parameters to control average diameter of CuNPs were found to be the introduction of additive agent, the feeding rate of reducing agent, and reaction temperature. The CuNPs with various average diameters (58, 40, 26, 20nm) could be synthesized by controlling these parameters. The dispersed solution of CuNPs with an average size of 20 nm was made with nonpolar solvent containing 3 wt% of binder, and then coated onto glass substrate. After sintering the coated substrates at $250^{\circ}C$ for 30 minutes in nitrogen atmosphere, metallic copper film resulted in a specific resistivity of $4.2\;{\mu}{\Omega}{\cdot}cm$.

• Korean Chemical Engineering Research
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• 제62권2호
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• pp.142-146
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• 2024

전세계적으로 천연화장품에 대한 관심과 수요가 크게 늘어나고 있다. 따라서 기존 화학합성 기능성화장품소재를 대체하기 위한 노력의 일환으로서 천연물에서 기능성화장품소재를 발굴하고자 하였다. 모자반은 우리나라의 해안 전지역에서 쉽게 볼 수 있는 갈조류의 일종으로서 식용으로도 이용되는 만큼 안전성이 확보되어있는 해조류이다. 본 연구에서는 큰잎 모자반(Sargassum coreanum). 짝잎 모자반(Sargassum hemiphyllum), 쌍발이 모자반(Sargassum patens)의 3가지 종류의 모자반으로부터 열수를 이용하여 유효성분을 추출하였으며, 항산화효과, 미백효과, 주름개선효과, 자외선흡수효과 및 항염증효과를 측정하여 기능성 화장품 소재로서의 응용 가능성을 살펴보고자 하였다. 모자반추출물은 세포독성시험결과 안전성이 매우 우수하였고, DPPH radical scavenging activity를 이용한 항산화능 측정결과 우수한 항산화능을 보여주었으며 tyrosinase inhibition을 이용한 미백효과시험에서는 큰잎 모자반(Sargassum coreanum)의 미백효과가 상당히 우수하였다. 그러나 주름개선효과, 자외선흡수효과와 항염증효과는 비교적 낮았다. 결론적으로 큰잎 모자반(Sargassum coreanum)은 세포독성이 적었고, 항산화효과와 미백효과가 우수하여 미백 기능성화장품소재로서 응용가능성이 높음을 알 수 있었다.

• 공업화학
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• 제19권2호
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• pp.242-248
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• 2008

철이 혼입된 FeMCM-41을 제조할 때 철의 전구체를 투입하는 시기에 따라 FeMCM-41의 특성이 다르게 나타났다. 철의 전구체를 주형물질 용액에 넣거나 주형물질과 규산나트륨 수용액의 혼합 후 투입하는 것보다는 pH의 조절 중에 투입하는 것이 철 전구물질의 투입에 가장 효과적인 방법으로 판단되었다. 규소로만 된 MCM-41을 만들고 여기에서 주형물질을 용매 추출해 낸 다음 철을 투입하는 경우에는 철이 혼입되는 양도 적고 혼입되더라도 대부분 골격 외부, 즉 세공 표면에 그대로 존재하는 것으로 판단되었다. 또한 각 시기별로는 철의 투입량이 증가함에 따라 철이 메조포어의 격자 내로 혼입되는 양에는 한계량이 존재하였다. FeMCM-41 촉매는 프로필렌의 산화반응에 활성을 보였으며, 철의 전구체를 투입하는 시기에 따라 제조한 것들 간의 반응성의 차이는 거의 발견되지 않았다.

• 소성∙가공
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• 제15권8호
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• pp.615-620
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• 2006

The reduction behavior of $TiO_{2}$ in Al and Al/CaSi containing self-reducing $TiO_{2}$ briquettes(SRTB) was investigated. The maximum yield of Ti was expected with the slag composition of 45-55%CaO in the $CaO-Al_{2}O_{3}$ system. When $CaCO_{3}$ was used as a flux, the oxidation loss of reducing agent by $CO_{2}$ should be compensated, and therefore it leads to excessive requirement of the reducing agent. By using Al and CaSi mixture as a reducing agent of $TiO_{2}$, the reaction products both oxide and metal could be liquefied, and separated effectively with each other. As a result, the yield of Ti increases remarkably. The optimum mixing ratio of CaSi to Al is 78%CaSi-22%Al.

• 한국환경과학회지
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• 제21권10호
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• pp.1187-1193
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• 2012

The aim of this research is to enhance the bottom environment of Geoje fish farm that has been severely contaminated. Treatment of microbial agent and/or calcium oxide significantly changed that environment: in ignition loss, either treatment (25% or 21%) showed better than mixed treatment (13.2%). In COD, the oxygen releasing agent or mixed treatment reduced the index by more than 20%. In T-P and T-N, the effects of $CaO_2$ on them were overwhelming (50% or more) meanwhile that of the microbial agent on them was less than 20%. Also, $CaO_2$ influenced on the microbial flora: Desulfobvibrio thermophilus, a sulfate reducing bacterium decreased in number, considering the increase of pH and rise of redox potential. In contrast, Pseudomonas sp., Pseudoalteromonas sp., Pseudomonas aeruginosa were remarkably dominant over other species with mixed treatment as a PCA analysis confirmed it.

• 한국분말재료학회지
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• 제28권1호
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• pp.25-30
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• 2021

The surface of silicon dummy wafers is contaminated with metallic impurities owing to the reaction with and adhesion of chemicals during the oxidation process. These metallic impurities negatively affect the device performance, reliability, and yield. To solve this problem, a wafer-cleaning process that removes metallic impurities is essential. RCA (Radio Corporation of America) cleaning is commonly used, but there are problems such as increased surface roughness and formation of metal hydroxides. Herein, we attempt to use a chelating agent (EDTA) to reduce the surface roughness, improve the stability of cleaning solutions, and prevent the re-adsorption of impurities. The bonding between the cleaning solution and metal powder is analyzed by referring to the Pourbaix diagram. The changes in the ionic conductivity, H2O2 decomposition behavior, and degree of dissolution are checked with a conductivity meter, and the changes in the absorbance and particle size before and after the reaction are confirmed by ultraviolet-visible spectroscopy (UV-vis) and dynamic light scattering (DLS) analyses. Thus, the addition of a chelating agent prevents the decomposition of H2O2 and improves the life of the silicon wafer cleaning solution, allowing it to react smoothly with metallic impurities.

• 한국염색가공학회지
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• 제21권1호
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• pp.38-45
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• 2009

First of all, the properties imparted to PET fabrics are resistance to and recovery from creasing or wrinkling when wet or dry; high resistance to stretch in the filament yarns but not in the staple; high abrasion resistance; good texture and appearance; resistance to heat ageing; good chemical resistance and good resistance, behind glass, to sunlight. But, the low moisture regain of PET fabric conduces to static troubles in textile processing. Furthermore, garments made from PET may, during wear, develop electric charges which attract to the fabric particles of soil(dirt, swarf, dust) flying in the air, so that the cuffs of shirts, for example, become soiled quickly and are not easily laundered clean. The sericin constitutes 25$\sim$30％ of silk protein and surrounds the fibroin fiber with sticky layer that supports the formation of a cocoon. The useful biochemical properties of sericin protein are oxidation resistant, antibacterial, UV resistant, hydrophilic property, and good affinity with hydrophobic material. These properties can be used as an improving reagent or a coating agent for natural and synthetic fibers, fabrics, and other intermediate products. The sericin is also applied to cross-link, and can be blended with other materials. In this study, we modified the surface of PET fabric by mixture of sericin finishing agent; sericin, polyuretane binder and 1,2,3,4-butanetetracarboxylic acid (BTCA) cross-link agent. Also, we investigated the finshing effect; moisture regain, stiffness, handle, drape and electrostatic. The moisture regain of PET fabric treated with sericin finishing agent was higher than that of untreated PET fabric. As a result of evaluating influence about handle of PET fabrics treated with sericin finishing agent, it was confirmed that the sericin finishing agent could be use as a linen like finishing agent.

• 한국재료학회지
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• 제21권8호
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• pp.419-424
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• 2011

Pt nanoparticle catalysts incorporated on $RuO_2$ nanowire support were successfully synthesized and their electrochemical properties, such as methanol electro-oxidation and electrochemically active surface (EAS) area, were demonstrated for direct methanol fuel cells (DMFCs). After fabricating $RuO_2$ nanowire support via an electrospinning method, two different types of incorporated Pt nanoparticle electrocatalysts were prepared using a precipitation method via the reaction with $NaBH_4$ as a reducing agent. One electrocatalyst was 20 wt% Pt/$RuO_2$, and the other was 40 wt% Pt/$RuO_2$. The structural and electrochemical properties of the Pt nanoparticle electrocatalysts incorporated on electrospun $RuO_2$ nanowire support were investigated using a bright field transmission electron microscopy (bright field TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. The bright field TEM, XRD, and XPS results indicate that Pt nanoparticle electrocatalysts with sizes of approximately 2-4 nm were well incorporated on the electrospun $RuO_2$ nanowire support with a diameter of approximately 50 nm. The cyclic voltammetry results showed that the Pt nanoparticle catalysts incorporated on the electrospun $RuO_2$ nanowire support give superior catalytic activity in the methanol electro-oxidation and a higher electrochemically active surface (EAS) area when compared with the electrospun Pt nanowire electrocatalysts without the $RuO_2$ nanowire support. Therefore, the Pt nanoparticle catalysts incorporated on the electrospun $RuO_2$ nanowire support could be a promising electrode for direct methanol fuel cells (DMFCs).

• 대한환경공학회지
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• 제22권1호
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• pp.73-81
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• 2000

지하수 내의 철분 제거를 위해 일반적으로 포기법과 화학적 산화제를 이용한 산화법이 이용된다. 특히 오염수 포기에 이은 고-액 여과 분리 공정은 가장 널리 이용되는 물리 화학적 처리법이다. 이 방법은 주로 pH 6.5 이상의 경우 산화 제1철의 불용화에 매우 효과적인 것으로 알려져 있다. 본 연구에서는 석회석을 일정한 포기 하에 오염수와 접촉시켜 pH를 6.5 이상으로 유지하였다. 회분식 실험에서 석회석 입도 크기, 초기 철분 농도, pH, 온도 및 이온 세기 등에 의한 산화 제1철의 산화속도 변화를 고찰하였다. 석회석의 입도가 감소할수록 pH의 증가가 두드러지며 철분 산화 또한 급격히 증가함을 알 수 있었다. 산화 제1철의 산화속도는 초기 철분 농도, 온도 및 이온세기에 비례하는 것으로 나타났다.