• 센서학회지
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• 제31권4호
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• pp.244-248
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• 2022

Recently, several studies on the development of superhydrophobic surfaces using various nano-sized carbon-based materials have been conducted. The superhydrophobic surfaces developed using carbon soot have advantages such as low processing cost and remarkable physical and chemical properties. However, their durability is low. To address this problem, in this study, a superhydrophobic surface with high durability and a multilayer structure was fabricated using ethanol vapor treatment. Candle soot was deposited on an aluminum substrate coated with paraffin wax, and a micro-nano multilayer structure with a size of several micrometers was fabricated via ethanol vapor treatment. The fabricated superhydrophobic surface was confirmed to have a contact angle of at least 156° and high durability. Finally, it was confirmed that ethanol vapor not only changed the nanostructure of carbon but also affected the durability of the structure.

• Korean Chemical Engineering Research
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• 제60권2호
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• pp.237-242
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• 2022

본 연구에서는 정제된(+)-dihydromyricetin로부터 잔류 용매를 효과적으로 제거할 수 있는 건조 방법을 개발하였다. 에탄올 전 처리를 통한 회전 증발(rotary evaporation)에 의해 잔류 아세톤 농도를 ICH 규정치(5,000 ppm) 이하로 효율적으로 제거하였다. 또한 잔류 에탄올 역시 물 첨가를 통한 회전 증발로 ICH 규정치(5,000 ppm)를 충족시켰으며 잔류 수분 함량은 4% 이내였다. 모든 건조 온도(35, 45, 55 ℃)에서 잔류 용매는 건조 초기에 급격히 제거되었으며 건조 효율은 건조 온도가 높을수록 증가하였다. 건조 메커니즘 조사 결과, 에탄올 전 처리에 의한 잔류 용매 제거는 아세톤-에탄올 혼합물의 높은 증기압과 아세톤-에탄올 간의 수소 결합과 연관됨을 알 수 있었다.

• 한국재료학회지
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• 제30권7호
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• pp.369-375
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• 2020

FDM 3D printing structures have rough surfaces and require post-treatment to improve the properties. Fumigation is a representative technique for removing surface unevenness. Surface treatment by fumigation proceeds by dissolving the surface of the protruding structure using a vaporized solvent. In this study, 3D printed PVB outputs are surface-treated with ethyl-alcohol fumigation. As the fumigation time increases, the surface flattens as ethanol dissolves the mountains on the surface of PVB and the surface valleys are filled with dissolved PVB. Through the fumigation process, the mechanical strength tends to decrease, and deformation rate increases. Ethanol vapor permeates into PVB, widening the distance between chains and resulting in weak bonding strength between chains. In order to confirm the effect of fumigation only, an annealing process is performed at 80 ℃ for 1, 5, 10, 30, and 50 minutes and the results of the fumigation are compared.

• Bulletin of the Korean Chemical Society
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• 제25권5호
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• pp.687-693
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• 2004

Composite membranes with a titania layer were prepared by soaking-rolling method with the titania sol of nanoparticles formed in the sol-gel process and investigated regarding the vapor permeation of various organic mixtures. The support modification was conducted by pressing $SiO_2$ xerogel of 500 nm in particle size under 10 MPa on the surface of a porous stainless steel (SUS) substrate and designed the multi-layered structure by coating the intermediate layer of ${\gamma}-Al_2O_3$. Microstructure of titania membrane was affected by heat-treatment and synthesis conditions of precursor sol, and titania formed at calcination temperature of 300$^{\circ}C$ with sol of [$H^+$]/[TIP]=0.3 possessed surface area of 210 $m^2$/g, average pore size of 1.25 nm. The titania composite membrane showed high $H_2/N_2$ selectivity and water/ethanol selectivity as 25-30 and 50-100, respectively. As a result of vapor permeation for water-alcohol and alcohol-alcohol mixture, titania composite membrane showed water-permselective and molecular-sieve permeation behavior. However, water/methanol selectivity of the membrane was very low because of chemical affinity of permeants for the membrane by similar physicochemical properties of water and methanol.

• 한국응용과학기술학회지
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• 제24권3호
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• pp.264-271
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• 2007

Effect of dispersion methods for Vapor Grown Carbon Fibers (VGCF) in epoxy caused the change in mechanical properties of VGCF/epoxy nanocomposites, such as tensile modulus and tensile strength. The influence of VGCF types - atmospheric plasma treated (APT) VGCF and raw VGCF - and their contents was discussed in detail. Treating VGCF with atmospheric plasma enhanced the surface energy, therefore improved the bonding strength with epoxy matrix. Two different methods used to disperse VGCF were ultrasonic and mechanical homogenizer methods. When using dispersion solutions, the VGCF demonstrated good dispersion in ethanol in both homogenizer and ultrasonic method. The uniform dispersion of VGCF was investigated by scanning electron microscopy (SEM) which showed well-dispersion of VGCF in epoxy matrix. The tensile modulus of raw VGCF/epoxy nanocomposites obtained by ultrasonic method was higher than that of one obtained by homogenizer method. APT VGCF/epoxy nanocomposites showed higher tensile strength than that of raw VGCF/epoxy nanocomposites.

• 한국응용과학기술학회지
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• 제34권4호
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• pp.874-882
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• 2017

국내 외에서 대기오염에 대한 관심이 점점 증가함에 따라 자동차 및 연료관련 분야의 연구자들은 새로운 엔진설계, 향상된 후처리장치, 청정연료 그리고 연료품질향상을 통해 자동차의 배출가스 감소를 위하여 지속적으로 노력해 왔다. 따라서, 본 연구에서는 자동차의 증발가스와 성능, 환경성에 대해 살펴보고자 하였으며, 연료의 옥탄가 향상제로 쓰이는 바이오 에탄올, 바이오 부탄올, 바이오 ETBE (Ethyl Tertia ry Butyl Ether), MTBE (Methyl Tertiary Butyl Ether)가 환경에 미치는 문제점에 대해 살펴보고자 하였다. 주로 휘발유의 옥탄가 향상제로 쓰이는 바이오 에탄올, 바이오 부탄올, 바이오 ETBE, MTBE가 휘발유 연료 특성 중 증발가스에 미치는 영향에 대해 살펴보았으며, 바이오 연료 특성에 대한 가솔린 자동차의 가속 및 동력 성능을 살펴보았다. 실험결과 증발가스는 최대 1.04g/test로 모든 시험 연료가 국내 배출가스 기준에 부합함을 알 수 있었으며, 원료에 대한 증기압 측정 결과 바이오에탄올 15kPa, 바이오 부탄올 1.6k Pa로 E3급 연료 제조 시 바이오 부탄올 함유량을 늘리면 증기압과 증발가스 또한 낮게 나타났다. 또한, 바이오 연료의 종류에 따라 유사한 가속 및 동력 성능을 나타내었으며, 바이오 부탄올과 바이오 에탄올 비교시 가속 성능이 약 3.9%, 출력은 0.8% 개선되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.251-251
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• 2016

For several decades, industrial processes consume a huge amount of raw water for various objects that consequently results in the generation of large amounts of wastewater. Wastewaters are consisting of complex mixture of different inorganic and organic compounds and some of them can be toxic, hazardous and hard to degrade. These effluents are mainly treated by conventional technologies such are aerobic and anaerobic treatment and chemical coagulation. But, these processes are not suitable for eliminating all hazardous chemical compounds form wastewater and generate a large amount of toxic sludge. Therefore, other processes have been studied and applied together with these techniques to enhance purification results. These include photocatalysis, absorption, advanced oxidation processes, and ozonation, but also have their own drawbacks. In recent years, electrochemical techniques have received attention as wastewater treatment process that could be show higher purification results. Among them, boron doped diamond (BDD) attract attention as electrochemical electrode due to good chemical and electrochemical stability, long lifetime and wide potential window that necessary properties for anode electrode. So, there are many researches about high quality BDD on Nb, Ta, W and Si substrates, but, their application in effluents treatment is not suitable due to high cost of metal and low conductivity of Si. To solve these problems, Ti has been candidate as substrate in consideration of cost and property. But there are adhesion issues that must be overcome to apply Ti as BDD substrate. Al, Cu, Ti and Nb thin films were deposited on Ti substrate to improve adhesion between substrate and BDD thin film. In this paper, BDD films were deposited by hot filament chemical vapor deposition (HF-CVD) method. Prior to deposition, cleaning processes were conducted in acetone, ethanol, and isopropyl alcohol (IPA) using sonification machine for 7 min, respectively. And metal layer with the thickness of 200 nm were deposited by DC magnetron sputtering (DCMS). To analyze microstructure X-ray diffraction (XRD, Bruker gads) and field emission scanning electron microscopy (FE-SEM, Hitachi) were used. It is confirmed that metal layer was effective to adhesion property and improved electrode property. Electrochemical measurements were carried out in a three electrode electrochemical cell containing a 0.5 % H2SO4 in deionized water. As a result, it is confirmed that metal inter layer heavily effect on BDD property by improving adhesion property due to suppressing formation of titanium carbide.

• 한국잠사곤충학회지
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• 제37권2호
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• pp.142-153
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• 1995

특이한 분자 구조를 가진 생체 고분자로서 유용한 견 피브로인은 다양하게 성형 가공할 수 있으며 이를 위해서는 견 피브로인 수용액을 필요로 한다. 견 피브로인의 용해 조건이 형성되는 견 피브로인의 분말과 필름에 미치는 영향을 알아보기 위하여 종성염과 산가수분해법으로 견 피브로인을 용해시킨 수용액으로부터 견 피브로인 분말과 필름을 제조하고 이들의 특성을 아미노산 조정 분석, SEM, DSC, IR, X-ray Diffraction 등의 방법을 통하여 조사 분석한 결과는 다음과 같다. 1. 염화칼슘법과 염산법에 의해 피브로이을 용해시켰을 때 처리에 따라 아미노산 조성은 달랐으며 분자량도 차이가 있었다. 2. 분말의 구조 분석 결과, 염화칼슘법에 의한 처리에서 열분해 온도는 대조에 비해 낮게 나타났고 무정형의 분자 구조를 띄고 있음을 알 수 있었다. 염산 처리에 의한 잔유물은 대조보다 높은 온도에서 $\beta$구조에 의한 분해 거동을 보였으며 높은 결정화도를 나타냈다. 한편 염산에 용해된 부분은 열분해 분석 결과 a-helix에 의한 흡열 peak을 나타냈다. 3. 염화칼슘법에 의해 형성된 견 피브로인 필름은 모정형에 가까운 결정 구조를 가지고 있지만 불용화 처리에 의해 결정성이 향상됨에 따라 피브로인 필름의 흡습율은 감소하였으며, 열분해 온도가 증가했다.