• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.466-466
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• 2011

There have been several methods to fabricate carbon nanotube (CNT) emitters, which include as-grown, spraying, screen-printing, electrophoresis and bonding methods. Unfortunately, these techniques generally suffer from two main problems. One is a weak mechanical adhesion between CNTs and the cathode. The as-grown, spraying and electrophoresis methods show a weak mechanical adhesion between CNTs and the cathodes, which induces CNT emitters pulled out under a high electric field. The other is a severe degradation of the CNT tip due to organic binders used in the fabrication process. The screen-printing method which is widely used to fabricate CNT emitters generally shows a critical degradation of CNT emitters caused by the organic binder. Such kinds of problems induce a short lifetime of the CNT field emitters which may limit their practical applications. Therefore, a robust CNT emitter which has the strong mechanical adhesion and no degradation is still a great challenge. Here, we introduce a simple and effective technique for fabrication of CNT field emitter, namely filtration-taping-transfer method. The CNT emitters fabricated by the filtration-taping-transfer method show the low turn-on electric fields, the high emission current, good uniformity and good stability. The enhanced emission performance of the CNT emitters is mainly attributed to high emission sites on the emitter area, and to good ohmic contact and strong mechanical adhesion between the emitters and cathodes. The CNT emitters using a simple and effective fabrication method can be applied for various field emission applications such as field emission displays, lamps, e-beam sources, and x-ray sources. The detail fabrication process will be covered at the poster.

• 한국입자에어로졸학회지
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• 제12권4호
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• pp.145-150
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• 2016

During the chemical mechanical planarization (CMP) process, slurry that comprises abrasive particles can directly affect the CMP performance and quality. Mainly, the large particles in the slurry can generate the defects on the wafer. Thus, many kinds of filters have been used in the CMP process to remove unwanted over-sized particles. Among these filters, the point-of-use (POU) filter is used just before the slurry is supplied onto the CMP pad. In the CMP research field, analysis of the POU filter has been relatively exceptional, and previous studies have not focused on the standardized filtration efficiency (FE) or filter performance. Furthermore, conventional evaluation methods of filter performance are not appropriate for POU filters, as the POU filter is not a membrane type, but is instead a depth type roll filter. In order to accurately evaluate the POU filter, slurry FE according to particle size was measured in this study. Additionally, a CMP experiment was conducted with filtered slurry to demonstrate the effects of filtered slurry on CMP performance. Depending on the flow rate and the filter retention size, the FE according to particle size was different. When the small and large particles have different FEs, the total filtration efficiency (TFE) can still have a similar value. For this reason, there is a need to measure the FE with respect to the particle size to verify the effects of the POU filter on the CMP process.

• 한국어병학회지
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• 제28권3호
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• pp.125-131
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• 2015

본 연구는 기계적 여과 후 자외선 살균처리한 양식장 유입수의 살균효율과 넙치 치어의 질병저감 효과를 평가하였다. 유입해수의 살균효율은 99.27%로 조사되었고, 기계적 여과 및 UV 살균처리 해수로 4개월 동안 사육한 넙치 치어는 대조구에 비하여 20~30%의 폐사율 저감효과가 관찰되었다.

• Composites Research
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• 제29권5호
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• pp.269-275
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• 2016

Multiscale hybrid composites, which consist of polymeric resins, microscale fibers and nanoscale reinforcements, have drawn significant attention in the field of advanced, high-performance materials. Despite their advantages, multiscale hybrid composites show challenges associated with nanomaterial dispersion, viscosity, interfacial bonding and load transfer, and orientation control. In this paper, carbon nanotube(CNT)/carbon fiber(CF)/polycarbonate(PC) multiscale hybrid composite were fabricated by a solution process to overcome the difficulties associated with controlling the melt viscosity of thermoplastic resins. The dependence of CNT loading was studied by varying the method to add CNTs, i.e., impregnation of CF with CNT/PC/solvent solution and impregnation of CNT-coated CF with PC/solvent solution. In addition, hybrid composites were fabricated through surfactant-aided CNT dispersion followed by vacuum filtration. The morphologies of the surfaces of hybrid composites, as analyzed by scanning electron microscopy, revealed the quality of PC impregnation depends on the processing method. Dynamic mechanical analysis was performed to evaluate their mechanical performance. It was analyzed that if the position of the value of tan ${\delta}$ is closer to the ideal line, the adhesion between polymer and carbon fiber is stronger. The effect of mechanical interlocking has a great influence on the dynamic mechanical properties of the composites with CNT-coated CF, which indicates that coating CF with CNTs is a suitable method to fabricate CNT/CF/PC hybrid composites.

• 멤브레인
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• 제13권3호
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• pp.131-142
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• 2003

원통형 회전 역삼투법은 높은 전단력과 유체의 불안정성을 결합시켜 막오염을 감소시키는 동적 여과방법이다. 이 논문은, 회전여과의 물리적 특성, 물질전달과 농도분극 현상, 이론적 및 실험적 해석, 사례연구 등 회전역삼투법에 대한 최근의 연구를 요약해서 보여준다.

• 대한기계학회논문집B
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• 제39권12호
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• pp.921-925
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• 2015

매년마다 신장질환으로 고통 받는 사람들이 증가하는 추세이다. 가장 흔한 치료법 중 하나는 혈액 투석인데, 이 방법은 많은 시간이 걸리고, 비용이 많이 드는 방법이다. 이러한 이유 때문에, 인공신장 연구의 중요성이 대두되고 있다. 혈액에서 크레아티닌을 여과하는 것은 신장의 주요 기능 중 하나이다. 우리는 이 기능에 초점을 맞춘 새로운 2 채널 마이크로 플루이딕 칩을 고안하였다. 두 개의 PDMS 층을 결합하기 위하여, 아크릴을 가공한 하우징 시스템이 개발하였으며, 이 방법은 여과막을 쉽게 바꿀 수 있다는 이점이 있다. 우리는 알루미늄 양극 산화물(AAO)을 여과막으로 사용하였다. 여과된 용액은 자페반응(Jaffe reation)을 이용하여, 크레아티닌 농도별 흡광도 차이를 분석하였다. 크레아티닌의 양에 대한 표준식을 만들어, 측정한 데이터를 보간하여 여과된 용액의 농도를 확인하였다. 실험을 통하여 유량 및 크레아티닌 농도에 따른 여과율을 얻을 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.18.2-18.2
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• 2009

Ceramics have some properties that are unmatched by other kind of materials like metals or polymers. The ability of high thermal and chemical resistance and in case of being superior in specific mechanical properties makes the ceramic materials suitable for arange of applications. The microstructure and morphology of a material arguably permit the use of many advanced application otherwise difficult to achieve.Porous structures have some important applications in biomedical and environmental field. For human hard tissue reconstruction and augmentation procedure suitable biomaterials are used with a desirable porosity. A range of porous bioceramics were fabricated with tailored design to meet the demand of specific applications. Channeled and interconnected porosity was introduced in alumina, zirconia, and hydroxyapatite or tri calcium phosphate ceramics by different methods like multi-pass extrusion process, bubble formation in viscous slurry,slurry dripping in immiscible liquid, sponge replica method etc. The detailed microstructural and morphological investigations were carried out to establish the unique features of each method and the developed systems. For environmental filters the porous structures were also very important. We investigated a range of channeled and randomly porous silicon based ceramic composites to enhance the material stability and filtration efficiency by taking advantage of the material chemistry of the element. Detailed microstructural and mechanical characterizations were carried out for the fabricated porous filtration systems.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.151-158
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• 2007

Filtration studies, using simulated test nanoparticles or diesel nanoparticles, have been performed about Inconel foam filters for DPF combined with electrostatic precipitation. The simulated test particles were synthesized by laser ablation in the nitrogen atmosphere at the standard condition. The diesel particles were exhausted from the diesel engine driven on the condition of idle or load mode. Filtration efficiency of the metal foam filter is very low because most of particles are penetrated through the large pores of filter. However, the efficiency was considerably improved by applying the electric field to the filter and/or charging the nanoparticles. Nevertheless, the pressure drop of filter hardly increased because the filter-pores were not clogged by deposited particles and kept open.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.78-88
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• 2007

In the present study a detailed examination of various porous media models for predicting filtration efficiency and pressure drop of diesel particulate filter (DPF), such as sphere-in-cell and constricted tube models, are attempted. In order for demonstrating their validities of correct estimation on permeability, geometry of property configurations common in commercial cordierite DPFs are correlated to the porous media flow models, and validations of predicted filtration efficiencies due to the use of different unit collectors are made with experiments. The result shows that the porosity, pore size and permeability of cordierite DPF can be successfully correlated by Kuwabara flow field with correction factor of 0.6. The unit collector efficiency predicted by sphere-in-cell model agrees very well with measurements in accumulation mode, whereas that by constricted tube model with significant prediction error.

• 한국산업융합학회 논문집
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• 제20권1호
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• pp.67-73
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• 2017

This study aimed to analyze the fluid inside the ceramic filtration dust collection system which was assumed to be a stationary 3-dimensional turbulence. The fluid dynamics data necessary for performance curves were obtained based on the analysis results. The governing equations used to compute the velocity distribution and pressure inside the catalyst converter were expressed with continuity and momentum equations. Furthermore, the ${\kappa}-{\varepsilon}$ turbulence model, already validated by the industry(coal factory, high temperature dust collector) was used for the study. Of a total of three computational models employed, Model-1 served as the basis for CFD analysis which took measurements in increments of 70mm.