• 대한조선학회논문집
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• 제45권6호
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• pp.637-645
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• 2008

It is very hard to control the quality of coating work in shipbuilding process, because it is highly affected by several parameters such as space between object and nozzle tip, spray velocity, pressure, tip size, etc.. Even so a coating work in shipbuilding is done by workers' experience and skill as yet. It causes not only an excessive use of paints but also a decrease of productivity. In order to solve this problem, we developed a formula that predicts the film thickness and determined the proper coating pattern. Also we had done a series of experiments to verify the results of this study.

• 한국기계가공학회지
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• 제10권2호
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• pp.61-66
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• 2011

The purpose of this paper is to design a hydraulic actuator to operate under high pressure conditions. The flow characteristics under design conditions of hydraulic actuator were numerically conducted by commercial fluid dynamic code(ANSYS CFX V11). The numerical analysis was performed by transient technique according to the variation of stroke times, which was changed from 0 to 1 second by interval of 0.01. Turbulence model, $k-\omega$ SST was selected to secure more accurate prediction of hydraulic oil flow. The ICEM-CFD 11 and CFXMesher, reliable grid generation software was also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate which was supplied to the hydraulic actuator was 30.4l/min. These results are in good agreement with design results within 3.5% error.

• 한국기계가공학회지
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• 제10권1호
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• pp.47-53
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• 2011

From recent research, it has revealed that Electroacitve polymer(EAP) has a physical limitation. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. In this paper, we suggest the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. Using mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we disperse Single-walled carbon nanotubes(SWCNT). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. In the result, we fabricated a disperse SWCNT/Nafion composite uniformly.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.538-541
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• 1996

The flow of the molten drop in the GMAW was observed to explain the mechanism of its formation and break-up process. Fluid flew analysis was made with the assumption that the electrode wire acts like fluid, and it is shown how the convection of the drop inside affects its flow, from the formation to the break-up of the drop. In later part, the process of the spray mode development at high current is shown, as well as the one of the globular mode, by the fluid flow analysis.

• Journal of Information Display
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• 제6권4호
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• pp.40-44
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• 2005

Nanometer-sized bismuth oxide with a diameter of about 80 nm was used as a new electron reflection material in a 29" Real Flat CPT. This bismuth oxide was well dispersed over pH8 in slurry. Spray coating was performed clearly and uniformly and was ensured that there was no clogging of shadow mask hole. Coating thickness was expressed to the brightness of chromaticity for the sprayed layer and was also well controlled during the spraying process. Doming was improved by about 10% in spite of the similar coating weight in comparison with the average 3.5 ${\mu}m$ of the conventional bismuth oxide.

• 분석과학
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• 제19권6호
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• pp.519-528
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• 2006

본 연구에서는 뇨시료를 고체상 추출법으로 추출한 후 HPLC/DAD/ESI-MS(high-performance liquid chromatograph/diode array detector/electro-spray ionitation mass spectrometry)를 사용하여 분석하였다. 7종의 thyroid hormones의 HPLC 분리조건은 Hypersil ODS(octadecylsilica) 컬럼(4.6mm I.D., 100 mm length, particle size $5{\mu}m$)을 사용하고 ammonium formate buffer와 acetonitrile을 이동상으로 하여 기울기 용리한 결과 완전 분리가 가능하였으며, UV spectra 및 질량스펙트럼을 확인할 수 있었다. 고체상 추출법에 의한 전처리 최적 조건을 조사한 결과 시료를 pH 3으로 한 후 C18 고체상을 사용하여 4 mL의 methanol/ammonium hydroxide(9:1) 혼합용액으로 용리할 경우 회수율이 89.0-113.1%로 나타났다. HPLC/DAD를 이용하여 10-1000 ng/mL범위에서 검량선을 작성한 결과 $r^2$값은 0.992-0.998 으로 나타났으며 검출한계는 2-4 ng/mL(3.8-13.0 pmol/mL)로 계산되었다.

• 자원리싸이클링
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• 제17권6호
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• pp.79-88
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• 2008

본 연구는 폐 주석의 리싸이클링을 통한 고기능성 주석 산화물 나노 분말의 대량제조 기술개발을 위한 전 단계 연구로서 주석 염화물 용액을 원료로 하여 분무열분해 반응에 의하여 평균입도 50nm 이하의 주석 산화물 분말을 제조하였으며 반응온도의 변화에 따른 생성 입자들의 특성 변화를 파악하였다. 열분해 반응온도가 $800^{\circ}C$로부터 $850^{\circ}C$로 증가함에 따라 형성된 입자들의 평균입도는 20 nm로부터 30 nm로 증가하였다. 또한 XRD 피크의 강도도 증가하였으며 비표면적은 1/2 정도로 크게 감소하였다. 반응온도 $900^{\circ}C$의 경우에는 액적 형태는 평균입도 30 nm 정도의 나노 입자들로 구성되어 있는 반면 독립된 입자들의 경우에는 평균입도가 $80{\sim}100\;nm$로 현저하게 증가 하였으며 입자 표면이 더욱 치밀화되어 있었다. 또한 XRD 피크 강도도 현저히 증가하였으며 비표면적은 현저하게 감소하였다. 반응온도 $950^{\circ}C$의 경우에는 액적 형태의 비율 및 크기가 현저히 감소하였으며 대부분의 입자들은 독립된 형태를 유지하고 있었으며 평균입도는 약 70 nm로 $900^{\circ}C$의 경우보다 오히려 감소하였다. 또한 XRD 피크의 강도도 $900^{\circ}C$의 경우에 비하여 현저히 감소하였으며 비표면적은 2배 정도 크게 증가하였다.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.335-342
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• 2013

In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

• 청정기술
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• 제8권2호
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• pp.101-110
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• 2002

회전형 도장기기의 개발을 위한 설계, 해석, 기초실험 및 성능시험 체계를 정립하였다. 도장기기의 설계 요구조건으로부터 도장기기 구성 요소들의 설계사양을 결정하는 개념설계 모델을 제안하였고, 이를 이용하여 각각의 도장기기 구성 요소를 설계, 해석하는 과정을 제시하였다. 설계된 도장기기의 무화특성 및 도장성능을 관찰하기 위한 실험 및 시험 방법을 기술하였고, 측정절차 및 측정변수의 평가기준을 확립하였다. 본 연구의 도장기기 개발체계를 이용한 실제 도장기기 개발 적용 사례를 제시함으로서, 본 방법의 신뢰성을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1891-1896
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• 2004

The present article proposes a new droplet collision model including the stretching separation regime and the formation of satellite droplets. The new model consists of a several equations to calculate the post-collision characteristics of colliding droplets and satellite droplets. These equations are derived from the energy balance of droplets between before and after collision. For binary collision of water droplets, the new model shows good agreement with experimental data for the number of satellite droplets. Nevertheless, it is thought that, in order to guarantee the generality of the new model, the improvements should be performed to consider the effects of the bouncing and the reflexive separation, which is essential process in the collision of hydrocarbon droplets.