• 한국환경보건학회지
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• 제27권1호
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• pp.1-7
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• 2001

Ammonia is used in the manufacture of fertilizers, refrigerants, stabilizers and many household cleaning agents. These wide applications resulted in ammonia contamination in water. Ammonia can be removed from water by physical, biological, and chemical methods. Ozonation is effictive in the treatment of water with low concentration of ammonia. This study is undertaken to provide kinetic data for the ozonation of ammonia with or without hydrogen peroxide. The results were as follows; The destruction rate of ammonia increased gradually with the influent hydrogen peroxide concentration up to 0.23 mM and inhibited in the range of 0.23~11.4mM, and the maximum removal rate of ammonia achieved at 0.23mM of hydrogen peroxide, and the overall kinetics was first order. The combination effect of hydrogen and ozone to oxide ammonia in aqueous solution was better than ozone alone. The reacted ammonia was converted completely to nitrate ion.

• 환경위생공학
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• 제17권2호
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• pp.1-10
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• 2002

Ammonia is used in the manufacture of fertilizers, refrigerants, stabilizers and many household cleaning agents. The wide applications result in ammonia contamination in water. Ammonia can be removed from water by physical, biological, and chemical methods. Especially ozonation is effective in the treatment of water with low concentration of ammonia. Therefore, this study is undertaken to provide kinetic data for the ozonation of ammonia with bromide. The results were as follows; Ammonia oxidized by ozone with bromide catalysis. The denitrification rate of the ammonia increased proportionally to the concentration of bromide, and the overall reaction order was zero. It was also found that the effect of bromide ion concentration on the denitrification can be expressed by Monod type equation and there was no more effect above a proper bromide ion concentration. The reacted ammonia was converted completely to nitrate ion without bromide, but the denitrification of ammonia by ozone was conducted in the presence of bromide.

• 동력기계공학회지
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• 제17권6호
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• pp.142-148
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• 2013

High-power ultrasonic promotes a chemical reaction by its own energy, thus it has been used for sonochemistry applications. For example, it has been mostly used for mixing, reaction catalyst, dispersion and disintegration. High-power ultrasonic transducer is made with structure based on a Bolt-clamped Langevin type Transducer (BLT), But it has difficulty in the development because degradation of piezoelectric ceramic by the heat generation of BLT. In this study, for a development of the transducer of 25 kHz and 1000 W used in sonochemistry and industrial cleaning, BLT with a hole in its center and tubular type waveguide of the transducer were designed based on finite element method (FEM). The transducer was fabricated based on the design parameter, and the impedance characteristics are measured experimentally and compared with the numerical results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.139-140
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• 2006

PZT박막은 비휘발성 재료로 유전율이 높고 항전력이 작으면서 잔류 분극랑이 크기 때문에 적합한 특성을 가지고 FeRAM에 매력적인 물질이다. CMP(chemical mechanical polishing)는 기존의 회생막의 전면 식각 공정과는 달리 특정 부위의 제거 속도를 조절함으로써 평탄화 하는 기술로 wafer 전면을 회전하는 탄성 패드 사이에 액상의 Slurry를 투입하여 연마하는 기술이다. 본 논문에서는 CMP 공정으로 제조한 PZT박막 캐패시터에서 CMP 후처리공정(세척)의 유무 및 종류에 따라 피로특성에 대하여 연구하였다, PZT 박막의 캐패시터의 피로 특성을 연구한 결과 CMP 후처리공정 SC-l용액을 사용하여 세정공정을 하였을때 가장 향상된 PZT 캐패시터의 피로특성이 나타났다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1992년도 추계학술발표강연 및 논문개요집
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• pp.6-6
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• 1992

Ionized cluster beam deposition (ICBD) technique has been employed to fabricate high-purity crystalline polyimide (PI) film. The pyromellitic dianhydride (PMDA) and oxydianiline (ODA) were deposited using dual ICB sources, Fourier trans forminfraredspectroscopy (FT-IR), X-ray photoemission spectroscopy (XPS), and Transmission electron microscopy (TEM)study show that the bulk and surface chemical properties and the crystalline structure are very sensitive to the ICBD conditions such as cluster ion acceleration voltage and ionization voltage, At optimum ICBD conditions, the PI films have a maximum imidization, negligible impurities(∼1% isoimide), and a good crystalline structure probably due to the high surface migration energy and surface cleaning effect. These characteristics are superior to those of films deposited by other techniques such as colvent cast, vapowr deposition, or sputtering techniques.

• 원자력산업
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• 제30권3호
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• pp.52-56
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• 2010

증기발생기 2차측 상태는 발전소 운영에 있어 중요한 역할을 수행한다. 기기, 배관 및 열교환기에서 발생되는 침적물은 증기발생기 튜브의 부식 원인이 될 수 있으며, 튜브와 튜브 지지판 사이의 공간을 차단한다. 2차측 침적물에 의한 튜브 파손으로 인해 일부 발전소에서는 강제적으로 발전을 정지하는 사례가 발생하였다. 또한 튜브 지지판의 침적물 축적으로 인해 정상 운전 동안 전력 생산을 감소하게 되는 결과를 초래한 발전소도 있었다. 따라서 증기발생기 2차측 상태 감시와 더불어 증기발생기 부품의 청결 유지는 필수 항목이라 할 수 있다. 웨스팅하우스에서는 증기발생기를 초기 제작 상태로 복구하고 2차측 침적물을 제거하기 위해 EPRI SGOG 증기발생기 화학 세정을 수 년간 이용하고 있다. 본고는 35개 이상의 발전소에서 성공적으로 이용하고 있는 화학 세정 프로세스 개요 및 프로세스를 적용하면서 취득한 경험을 요약한 것이다.

• 한국세라믹학회지
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• 제28권7호
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• pp.517-524
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• 1991

The CVD process of BPSG (BoroPhosphoSilicate Glass) and its thin film properties were studied. B2H6, PH3, SiH4 and O2 gases were reacted in a AP (Atmospheric Pressure) CVD system in the temperature range of 300℃ and 460℃. The interaction of B2H6 and PH3 was studied from the deposition rate and dopant incorporation change point of view. The dependency of BPSG step coverage on the temperature was changed with different O2/(B2H6+PH3+SiH4) ratio. Finally, the boundary which distinguishes the stable BPSG's from the ones that react with Di (Deionized) water or cleaning chemicals such as H2SO4, HCl, H2O2, NH4OH etc could be defined.

• Transactions on Electrical and Electronic Materials
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• 제1권1호
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• pp.6-11
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• 2000

The hydrogen plasma treatment of silicon wafers in the reactive ion-etching mode was studied for the application to silicon-on-insulator wafers which were prepared using the wafer bonding technique. The chemical reactions of hydrogen plasma with surface were used for both surface activation and removal of surface contaminants. As a result of exposure of silicon wafers to the plasma, an active oxide layer was found on the surface. This layer was rendered hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposing time and power. In addition, the surface became smoother with the shorter plasma exposing time and power. The value of initial surface energy estimated by the crack propagation method was 506 mJ/㎡, which was up to about three times higher as compared to the case of conventional direct using the wet RCA cleaning method.

• 한국의상디자인학회지
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• 제5권3호
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• pp.15-23
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• 2003

Chestnut trees have been used as a dyeing material, which are grow naturally, are cultivated all the area of Korea. So, there is abundant amount of the materials and they have better colorfastness than other natural dyeing materials. But chestnut husk extract is good at silk and wool fabrics, not cotton fabrics. That's why many methods using chestnut extraction for dyeing are being studied. But most of them depend on treatment method with chemical material which doesn't fit with the aim, using natural materials. Therefore in this research, we used protein pre-treatment method which is dyeing chestnut husk extract after treating at cotton fabrics with bean sap. And we studied the effect of dyeability of chestnut husk extract to cotton fabrics. As a result of pre-treatment of bean sap at cotton fabrics, dyeability was increased. Besides laundering fastness, dry cleaning fastness, perspiration fastness and light fastness were almost increased.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.73-78
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• 2006

The occurrence of detrimental substances in the paper machine leads to reduced economic performance of paper mills through reduced capacities due to increased paper breaks and cleaning times. In this article the latest generation of BASF's laser optical pitch particle counter is employed in the examination of a paper mill operating two paper machines and using a mixture of thermo-mechanical pulp and recycled fibres. The potential of the new instrument to differentiate between particles on the basis of size and chemical composition is discussed. In addition, direct evidence of the periodic and locational variation of detrimental substances in the paper machine is given. Finally, an example of the application of BASF's laser optical pitch particle counter in the selection of a suitable fixative system for a complex furnish is presented.