• 한국레이저가공학회지
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• 제6권3호
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• pp.29-35
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• 2003

In semiconductor processing, there are two types of particle contaminated onto the wafer, i.e. dry and wet state particles. In order to evaluate the cleaning performance of laser shock wave cleaning method, the removal of 1 m sized alumina particle at different particle conditions from silicon wafer has been carried out by laser-induced shock waves. It was found that the removal efficiency by laser shock cleaning was strongly dependent on the particle condition, i.e. the removal efficiency of dry alumina particle from silicon wafer was around 97％ while the efficiencies of wet alumina particle in DI water and IPA are 35％ and 55％ respectively. From the analysis of adhesion forces between the particle and the silicon substrate, the adhesion force of the wet particle where capillary force is dominant is much larger than that of the dry particle where Van der Waals force is dominant. As a result, it is seen that the particle in wet condition is much more difficult to remove from silicon wafer than the particle in dry condition by using physical cleaning method such as laser shock cleaning.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권10호
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• pp.710-715
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• 1999

The purpose of this work is to develop a high-efficiency air cleaning system for air pollutants such as particulate and gaseous state in indoor environments. In order to enhance a removal efficiency of gaseous state pollutants, we suggested that pulsed discharge plasma be combined with $TiO_2$ photocatalyst (photocatalytic plasma air cleaning unit). We investigated experimentally the basic characteristics of photocatalytic plasma air cleaning unit and measured air pollutants removal efficiency. The wavelength of light radiated from pulsed discharge plasma under the atmospheric condition was 310~380nm. Its energy is enough to excite the $TiO_2$ photocatalyst and it makes a photochemical reaction in the surface of $TiO_2$ photocatalyst. The removal quantity of trimethylamine$((CH_3)_3N)\; was\; 130mg/m^34 which is twice quantity of pulsed discharge plasma without $TiO_2$ phtocatalyst unit. From the result of gas analysis using FT-IR, nitric oxide was not detected and trimethylamine was decomposed to $H_2O\; and \;CO_2$. And trimethylamine removal efficiency was 95%. These experimental results indicate that photocatalytic plasma air cleaning unit is a potential method in removing the pollutants.

• 한국산학기술학회논문지
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• 제11권3호
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• pp.1016-1022
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• 2010

액상 중유 연료를 사용하는 고용량 증기 보일러에서 발생되어 연소기기 내부에 침적되는 슈트, 슬래그, 크랭커, 회분, 산화물의 on-line 세정을 위한 세정제 제조에 대한 연구를 수행하였다. 액상 중유 연료를 사용하는 보일러 및 가열로에 생성되는 슈트, 슬래그, 크랭커, 회분, 산화물을 제거하는 기존 기술은 보일러 및 가열로의 가동 중단 후 작업자들에 의한 기계적인 처리를 통하여 침적물을 제거하는 기술을 사용하고 있다. 기존 기술을 대치할 수 있고 보일러의 중단이 없는 상태에서 침적물을 세정할 수 있는 세정제의 최적 조성을 도출하였다. 질산암모늄과 질산마그네슘의 혼합물이 주 세정제로 도출되었으며, 각종 전이금속 화합물에 의한 영향을 영향을 연구하여, 세정에 의한 부식을 방지할 수 있으며, 연소효율의 증대를 얻을 수 있는 전이금속화합불 첨가제를 도출하였다.

• 상하수도학회지
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• 제31권2호
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• pp.169-175
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• 2017

This study applied microbubbles to reduce membrane fouling in wastewater reuse membrane processes, evaluated and compared the transmembrane pressure with or without the application of microbubbles and the cleaning efficiency with the application of aeration and microbubbles. In addition, this study analyzed foulants removed from the membrane surface. Changes in the transmembrane pressure of membranes with the presence or absence of microbubbles were observed. As a result, transmembrane pressure (TMP) increasing rate decreased twofold when applying microbubbles to realize stable operations. This study compared and evaluated cleaning efficiency applying aeration and microbubbles. As a result, the cleaning efficiency was 5% higher on average when applying microbubbles. In turbidity and total organic carbon (TOC), foulants were discharged when applying microbubbles twice as much as applying aeration. It is thought that particulate foulants precipitated on the membrane surface were more likely to desorb because the adhesion between the membrane surface and particle was weakened by microbubbles. Therefore, it is considered possible to effectively control membrane fouling because of the increase in cleaning efficiency when applying microbubbles to wastewater reuse membrane processes.

• 한국분무공학회지
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• 제12권4호
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• pp.185-190
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• 2007

There is a growing interest to develop a new cleaning technology to overcome the disadvantages of wet cleaning technologies such as environmental pollution and the cleaning difficulty of contaminants on integrated circuits. Laser cleaning is a potential technology to remove various pollutants on a wafer surface. However, there is no fundamental data about cleaning efficiencies and cleaning mechanisms of contaminants on a wafer surface using a laser cleaning technology. Therefore, the cleaning characteristics of a wafer surface using an excimer laser were investigated in this study. Fingerprint consisting of inorganic and organic materials was chosen as a representative of pollutants and the effectiveness of a laser irradiation on a wafer cleaning has been investigated qualitatively and quantitatively. The results have shown that cleaning degree is proportional to the laser irradiation time and repetition rate, and quantitative analysis conducted by an image processing method also have shown the same trend. Furthermore, the cleaning efficiency of a wafer contaminated by fingerprint strongly depended on a photothermal cleaning mechanism and the species were removed in order of hydrophilic and hydrophobic contaminants by laser irradiation.

• Membrane and Water Treatment
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• 제8권2호
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• pp.149-160
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• 2017

This study investigated effects of NaOH cleaning on the intrinsic permeability of polyvinylidene fluoride (PVDF) membranes and flux recoveries and membrane resistances under various conditions encountered during ultrafiltration in water treatment plants. The NaOH cleaning using 10,000 mg/L NaOH led to discoloration of PVDF membranes and had little effect on water flux. The NaOH cleaning was efficient in removing the fouling layer caused by humic water. However, long filtration induced a fouling layer that was not removed easily by NaOH cleaning. The lower temperature during filtration yielded rapid increases in transmembrane pressure and decreases in NaOH cleaning efficiency. The alkaline cleaning of PVDF changed the membrane properties such as the hydrophobicity and morphology. Foulant properties, operational conditions such as temperature, and chemical agents should be considered for cleaning strategies for PVDF applied in water treatment.

• Korean Chemical Engineering Research
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• 제48권3호
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• pp.401-404
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• 2010

본 연구에서는 PCB의 먼지 제거용 세정제로 사용되는 스프레이형 세정제를 선정하였다. 전자 반도체 부품의 세정에서 분무 세정의 원리를 적용시킨 제품의 분사력을 평가하기 위해 기판(IPC-A-36)을 사용하여 세정제를 분사하여 분사시간에 따라 그 이동거리를 비교하였다. 철가루와 먼지를 오염물, 기판(IPC-A-36)을 시편으로 하여 일반시험 평가법의 방법 중 가장 보편적으로 쓰이는 중량법으로 오염물에 따른 세정성능을 측정하여 비교하였다. 기판의 이동거리는 분사 시간이 늘어남에 따라 증가하였다. 1회 세정 시(3초간 분사) 먼지와 철가루는 오염물의 양이 증가함에 따라 세정효율이 감소하였고 특히 먼지 오염물은 매우 급격한 세정효율의 감소를 보였다.

• Journal of Biosystems Engineering
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• 제33권4호
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• pp.230-238
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• 2008

Mechanization such as machine harvesting, precleaning, drying and cleaning for rapeseed harvested with high moisture content should be accomplished for biodiesel production. In addition, machine drying and cleaning is inevitable in the mechanization of work, just because rice should be transplanted right after harvesting rapeseed in Korea. Particularly, early harvested rapeseed with the combine have high moisture content and undesirable materials such as stalks and stones which make drying-process difficult and lower the efficiency of drying. Therefore, this study was conducted to develop precleaner and cleaner which could remove foreign substances from harvested rapeseeds. The precleaner consists of throw-in hopper, conveyor, feeding hopper, two precleaning sieves and discharging sections. Precleaning capacity was 1,505 kg/hr in shaking frequency of 370 cpm (cycles per minute) and tilt angles of between $5^{\circ}$ and $7^{\circ}$. The efficiency of precleaning was between 90.9% and 91.5%. The cleaner consists of feeding, shaking, blowing, cleaning and discharging sections. Cleaning performance was 435.4kg/hr in the number of rocking motions of 475 cpm and tilt angle of $10^{\circ}$. The ratios of cleaning, foreign substances and loss were 96.5%, 3.5% and 0.2%, respectively.

• 청정기술
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• 제16권3호
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• pp.162-171
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• 2010

본 연구에서는 유기산, 무기산, 여러 첨가제들을 이용하여 옥내급수관의 스케일 제거에 적합한 환경친화적인 세정제를 개발하고자 연구를 수행하였다. 여러 유기산 중에서 oxalic acid, citric acid, malic acid 등의 경우 산화철 제거에 비교적 좋은 효율을 보였다. 이들 유기산들을 주축으로 하여 보조제를 첨가하여 옥내급수관 스케일의 주성분인 산화철 제거 평가실험을 하였다. 여러 첨가제 중에 비이온 계면활성제가 산화철 제거력 향상에 매우 뛰어남을 확인할 수 있었다. 그리고 산화철에 대해 높은 용해력을 보인 두 종류의 배합세정제 $F_1$과 $F_2$를 제조하였는데 배합세정제 $F_1$의 경우 유기산과 첨가제로만 이루어져 있어 기존의 화학세척제에 비하여 안전하고 환경친화적이지만 비교적 산화철 용해력이 조금 떨어졌고, $F_2$의 경우는 $F_1$에 무기산을 소량 첨가함으로 산화철 용해력을 보완해 줌으로써 보다 높은 산화철 세정력을 필요로 할 때 사용하는 것이 좋을 것으로 판단된다. 따라서 옥내급수관 세정 시 스케일의 정도에 따라 배합후보 세정제를 선택하는 것이 바람직하다고 판단된다.

• 한국표면공학회지
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• 제28권1호
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• pp.23-33
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• 1995

AISI 304 stainless steel has high resistance to corrosion due to the presence of a self-healing chromium oxide film on the surface, which also accounts for the difficulty in plating. Surface cleaning of this alloy is of fundamental importance in gold plating since its effectiveness puts an upper limit on the quality of the final coating. The cleaning of AISI 304 stainless steel was investigated with elimination of artificial passive oxide film and degreasing of remaining buffing wax as stearic acid. The familiar cleaning methods i.e. ultrasonic cleaning, electro-cleaning and activation treatment were fabricated in this study. Activation treatment showed best cleaning efficiency for elimination of passive oxide film among these methods, which was also confirmed by AES (Auger electron spectrometer) analysis. However, the best condition of cleaning was obtained by combining these methods. Electrocleaning time, for degreasing the stearic acid layer, was decreased with increasing amount of added KCN.