• 환경위생공학
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• 제23권3호
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• pp.1-8
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• 2008

Currently, medical waste stoker incinerator is widely used in the emission control technology of health-care risk waste and miscellaneous contaminated waste. In the past, wet type control technology was used to remove the major harmful gaseous contaminants of medical waste such as HCl, $NO_x,\;SO_2$, CO, DUST, Dioxin. However, the treatment cost for wastewater was high and it has a disadvantage for frozen system during winter season. Therefore, in order to obtain effective treatment, the dry type control technology was developed and widely used to remove the gaseous contaminants. In this study, pre-coated bag filter using hydrated lime, ($Ca(OH)_2$), was applied to the dry type control system and the optimum dose of hydrated lime was investigated. The treatment results showed that the dust collection rate was approximately 26.7%. Moreover, the HCl removal rate using pre-coated bag filter ($50mg/sm^3\;Ca(OH)_2$) was 13.52%, which was significantly higher than 3.26% obtained from conventional bag filter.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.759-762
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• 2003

The epitaxially grown Mg-doped GaN thin film was prepared by MOCVD (Metal Organic Chemical Vapor Deposition) for a SAW(Surface Acoustic Wave) filter. Mg-doped GaN thin film had enough properties for a SAW filter which include crystallinity and morphology. The surface morphology and crystalline of the Mg-doped GaN thin films were characterized using AFM and an X-ray rocking curve. The SAW filter, which was fabricated by lift-off process and frequency response, was measured by HP 8753C network analyzer. Center frequency was 96.687 MHz and SAW velocity was 5801 m/s when wavelength(λ) was 60${\mu}{\textrm}{m}$. Insertion loss was over -10 dB, Q was factor over 200, and side lobe attenuation was over 22 dB which was suitable for use as a SAW filter. Electro-mechanical coupling coefficient (k$^2$) was calculated from the measured data. k$^2$ was from 1 % to 1.44 %. The fabricated SAW filter using Mg-doped GaN/sapphire structure has good qualities as a filter and will be used as a SAW filter for operating RF frequency.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.581-587
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• 2021

In recent years, contamination of drinking water sources has emerged as a serious social problem, such as a large number of impurities in tap water or groundwater or the supply of suitable water due to rust of pipes. Although the government and public institutions are implementing various measures to protect water sources, they cannot improve water quality in a short period of time because of the enormous cost involved. Therefore, in recent years, preference has been given to a device that converts tap water, which is hard water, into soft water by installing a separate water softener at the faucet from which tap water is discharged. However, the existing filtration device has a problem that filtration performance is gradually lowered when impurities accumulate in the filter, requiring continuous filter replacement. In this study, the optimal design of the filter housing was performed to develop a water softener that can be washed when impurities accumulate on the filter inside the water softener connected to the faucet. For optimal design of the filter housing, fluid and fluid-structural interaction analysis were performed on the design pressure to determine the shape and thickness of the housing, and design review was performed through prototype.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.185-188
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• 2001

Chemical mechanical polishing(CMP) process is widely used for global planarization of inter-metal dielectric (IMD) layer and inter-layer dielectric (ILD) for deep sub-micron technology. However, as the IMD and ILD layer gets thinner, defects such as micro-scratch lead to severe circuit failure, which affect yield. In this paper, for the improvement of CMP process, deionized water (DIW) pressure, purified $N_2 \; (PN_2)$ gas, slurry filter and high spray bar were installed. Our experimental results show that DIW pressure and $PN_2$ gas factors were not related with removal rate, but edge hot-spot of patterned wafer had a serious relation. Also, the filter installation in CMP polisher could reduce defects after CMP process, it is shown that slurry filter plays an important role in determining consumable pad lifetime. The filter lifetime is dominated by the defects. However, the slurry filter is impossible to prevent defect-causing particles perfectly. Thus, we suggest that it is necessary to install the high spray bar of de-ionized water (DIW) with high pressure, to overcome the weak-point of slurry filter. Finally, we could expect the improvements of throughput, yield and stability in the ULSI fabrication process.

• Korean Chemical Engineering Research
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• 제43권6호
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• pp.691-695
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• 2005

종이 필터, 면섬유, 유리섬유 필터 등과 같은 지지체 위에 이차성장 수열합성법에 의하여 제올라이트 박막을 제조하였다. 먼저, 제올라이트 종자로 사용하기 위하여 제올라이트 NaA(${\approx}0.5{\mu}m$)와 silicalite-1(${\approx}0.2{\mu}m$) 결정들을 합성하였고, 이 결정들을 지지체의 표면에 화학결합을 이용하여 부착시켰다. 종자 결정으로 덮힌 지지체 위에 NaA나 silicalite-1 제올라이트 박막이 생성되었으며, 제조된 박막은 주사형 전자현미경으로 관찰하였고, X-ray 회절로 분석하였다.

• Macromolecular Research
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• 제16권1호
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• pp.31-35
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• 2008

Photoreactive polymers as a color filter resist containing both photoreactive acrylate and cinnamate double bonds were synthesized usin two step reactions. The chemical structures of the synthesized polymers were confirmed by $^1H$-NMR and FT-IR spectroscopy. The photoreactive polymers were quite soluble in most common organic solvents and produced excellent quality thin films by spin-coating. The photocuring kinetics of the acrylate and cinnamate double bonds were examined by FT-IR and UV- Vis spectroscopy, which confirmed the excellent photoreactivity of both the acrylate and cinnamate double bonds in the polymers. Upon UV irradiation, photocuring was almost completed within approximately 5 min, irrespective of the type of the prepolymers. The polymers also exhibited superior thermal stability, showing little change in transmittance in the visible region even after heating to $250^{\circ}C$ for one hour. Photolithographic micropatterns could be obtained with a resolution of a few microns.

• 공업화학
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• 제24권4호
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• pp.357-362
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• 2013

High efficiency particulate air (HEPA) 필터를 시험하기 위하여 단분산 polystyrene latex spheres (PLS) 및 PS-MPS/실리카복합 나노구체가 이용되었다. 사용된 모든 나노구체들은 필터시험 전에 평균입경과 변동계수 값을 측정하여 시험용 인조먼지로서 적정함을 평가하였다. PLS 및 복합 나노구체의 입경은 유화중합 중 반응온도와 안정제의 양을 조절하여 100~300 nm 범위에서 잘 조절되었으며, 변동계수의 경우도 단분산 입자분포로 판단되는 15%보다 낮은 3~7% 범위이었다. 한편 HEPA 필터시험 결과는 사용된 모든 나노구체들이 공기필터의 시험을 위한 시험용 인조먼지로서 아주 적절함을 보여주었다.

• 한국물환경학회지
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• 제18권4호
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• pp.387-394
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• 2002

본 연구는 $TiO_2$ 광촉매 및 응집-여과-중화공정을 거친 아크릴폐수를 UF(tubular)/RO(spiral wound)공정에 적용하여 적용압력과 온도변화에 따른 성능변화를 고찰하였다. 한외여과 관형모듈에서 광촉매 전처리수와 응집-여과-중화 전처리수의 COD, T-N은 온도 및 압력변화에 크게 영향을 받지 않고, 제거효율도 낮은 것으로 확인할 수 있었다. TDS 및 turbidity의 경우 한외여과 관형 모듈에서 광촉매 전처리수가 응집-여과-중화공정의 처리수에 비해 처리효율이 우수함을 확인하였다. T-N, TDS는 역삼투막 공정에서 우수한 제거효율을 나타내었다.

• Environmental Engineering Research
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• 제20권2호
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• pp.199-204
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• 2015

In this study, a novel phosphorus removal filter made of brass scrubber with higher porosity of over 96% was fabricated and evaluated. The brass scrubber was surface-modified to form copper hydroxide on the surface of the brass, which could be a phosphate removal filter for advanced wastewater treatment because the phosphates could be removed by the ion exchange with hydroxyl ions of copper hydroxide. The evaluation of phosphate removal was performed under the conditions of the batch type in wastewater and continuous type through filters. Filter recycling was also evaluated with retreatment of the surface modification process. The phosphate was rapidly removed within a very shorter contact time by the surface-modified brass scrubber filter, and the phosphate mass of 1.57 mg was removed per gram of the filter. The possibility of this surface-modified brass scrubber filter for phosphorus removal was shown without undesirable sludge production of existing chemical phosphorus removal techniques, and we feel that it would be very meaningful as a new wastewater treatment.

• Elastomers and Composites
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• 제38권3호
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• pp.243-250
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• 2003

국내에서 폴리우레탄 방수 코팅은 노후된 건축물의 지붕 수리와 다양한 스포츠시설의 시공으로 인하여 수요가 증가되고 있다. 본 연구에서는 일반적으로 많이 사용되고 있는 탄산칼슘 충진제의 일부를 비산재로 대체하여 폴리우레탄 코팅을 제조하였다. Cyclone과 Bag filter에서 수집된 비산재가 대체할 수 있는 탄산칼슘의 최대량은 각각 20%와 10%로 결정되었다. 폴리우레탄의 경화속도는 Pb-octoate 촉매를 사용하여 조절할 수 있었다. 코팅의 제조에 사용되는 성분들의 상대적인 양을 조절하면, 비산재를 함유하는 폴리우레탄 코팅의 인장강도, 인열강도 및 신장율 등이 폴리우레탄 코팅의 표준 값들과 유사하게 되었다. 그러나 bag filter에서 수집된 비산재를 사용할 경우에는, 제조된 폴리우레탄 코팅으로부터 카드뮴(Cd), 수은(Hg) 및 납(Pb)이 허용 수치보다 높게 용출되었다. 한편, cyclone으로부터 수집된 비산재를 사용해서 제조한 폴리우레탄 코팅은 더 우수한 기계적 특성을 보였으며 중금속의 용출양도 심각하지 않았다. 결론적으로, 적당한 비산재를 선정하여 사용한다면, 비산재 함유 폴리우레탄 코팅도 현장에서 활용될 수 있을 것이다.