• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.210.2-210.2
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• 2016

An inductively coupled plasma source was prepared for the deposition of a-C:H thin film. Properties of the inductively coupled plasma source are investigated by fluid simulation including Navier-Stokes equations and home-made tuned single Langmuir probe. Signal attenuation ratios of the Langmuir probe harmonic frequency were 13.56Mhz and 27.12Mhz. Dependencies of plasma parameters on process parameters were accord with simulation results. Ar/CH4 plasma simulation results shown that hydrocarbon radical densities have their lowest value at the vicinity of gas feeding line due to high flow velocity. For input power density of 0.07W/cm3, CH radical density qualitatively follows electron density distribution. On the other hand, central region of the chamber become deficient in CH3 radical due to high dissociation rate accompanied with high electron density. The result suggest that optimization of discharge power is important for controlling deposition film quality in high density plasma sources.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.143.1-143.1
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• 2015

An inductively coupled plasma source driven by 13.56MHz was prepared for the deposition of a-C:H thin film. Properties of the plasma source are investigated by fluid simulation including Navier-Stokes equations and home-made tuned single Langmuir probe. Signal attenuation ratios of the Langmuir probe at first and second harmonic frequency were 13.56Mhz and 27.12Mhz respectively. Dependencies of plasma parameters on process parameters were agreed with simulation results. Ar/CH4 plasma simulation results shown that hydrocarbon radical densities have their lowest value at the vicinity of gas feeding line due to high flow velocity. For input power density of 0.07W/cm3, CH radical density qualitatively follows electron density distribution. On the other hand, central region of the chamber become deficient in CH3 radical due to high dissociation rate accompanied with high electron density. The result suggest that optimization of discharge power is important for controlling deposition film quality in high density plasma sources.

• 한국환경과학회지
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• 제23권11호
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• pp.1835-1842
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• 2014

The goal of this study was to evaluate micro-bubble concentration ($C_{air}$) in water by air/water ratio (A/W ratio) with a micro-bubble generating pump. The estimation of micro-bubble concentration is based on the balance of inlet/outlet air and water flow rate. On net A/W ratio to be generated micro-bubble, we found that the obtained the $C_{air}$ are shown as a function of discharge pressure ($P_g$) of the micro-bubble generating pump. The correlation of the $C_{air}$ and the $P_g$ ($C_{air}=3.261P_g-1.754$) was adequately described by the least square methods with a high correlation coefficient (r = 0.9459) and calculated values fit the experimental data quite well. The $C_{air}$ was lower than theoretical dissolved air concentration ($C_{aq}$) calculated by Henry's law. The $C_{air}$ for being operated the micro-bubble generating pump was 6.75 - 39.53 mL/L, however, we found that the optimum of the $C_{air}$ to generate micro-bubble was the range from 10 to 12 mL/L.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1533_1534
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• 2009

This paper presents an atmospheric micro glow plasma-jet device. The device consists of four components; a thin Ni anode, a porous alumina insulater, a stainless steel cathode and an aluminum case. The Ni anode is fabricated using micromachining technology. The anode has 10 holes, of which the hole diameter and the depth are $250{\mu}m$ and $60{\mu}m$, respectively. The discharge test is performed in nitrogen gas at atmospheric pressure for 20 kHz AC bias. The breakdown voltage is 3.5 kV at gas flow rate of 4 L/min and the the plasma-jet is blown out to ambient at 5.5 kV. In order to verify the characteristics of plasma, the current and the voltage of device are measured. The maximum temperature of plasma is $37^{\circ}C$. The plasma is well generated and stable at high voltage.

• 한국정밀공학회지
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• 제33권3호
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• pp.207-216
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• 2016

A gerotor is suitable for miniature manufacturing because it has high discharge per 1 cycle and a simple structure, while also being widely used for lubrication oil of engines and as a hydraulic source of automatic transmission. In the automobile industry, improvements in fuel efficiency and noise reduction have recently come to the fore. It has also been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor and port shape design. In this study, to develop an optimal gerotor with a new lobe shape, 2-ellipses-combined, the equation of the lobe shape was derived, and CFD analysis results were compared for 2-ellipses with those of the previous gerotors (3-ellipses and ellipse1-involuteellipse2). A performance test for the oil pump with the optimal rotor (2-ellipses) was carried out and showed good agreement with the results obtained from CFD analysis.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.99-107
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• 2004

Lubrication characteristics between a cylinder block and a valve plate for high speed bent-axis type hydraulic pump play an important role in volumetric efficiency and durability of pump. In this paper, a finite element method is presented for the computation of the pressure distribution between a cylinder block and a valve plate for high speed bent-axis type hydraulic pump. Also, a Runge-Kutta method is applied to simulate the cylinder block dynamics of three-degrees of freedom motion. From the results of computation, we can draw two major conclusions. One is related to the fluid film characteristics between a cylinder block and a valve plate and the other is related to the average leakage that is determined by the pressure gradient and the clearance near the discharge port. The numerical results of cylinder block dynamics were compared with the experimental results using eddy-current type gap sensors those are fixed at a pump housing.

• 한국산학기술학회논문지
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• 제13권6호
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• pp.2479-2483
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• 2012

본 논문은 휴대 및 이동이 가능한 개인용 소형 산소발생기 개발에 관한 것이다. 소형 산소발생기는 소형 진공펌프에 의해 진공흡착방식으로 작동된다. 각 구성품을 소형화와 경량화에 맞춰 구성하였으며 토출펌프 회전속도, 노즐 직경, 3-way 밸브 작동시간을 변화시키면서 산소농도와 유량을 최적화하였다. 노즐 직경 0.5mm에서 발생된 산소농도는 약 37%이며 유량은 $1{\ell}$/min이다. 노즐로부터 30cm 떨어진 위치에서 약 0.5%의 농도증가 효과가 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.183-187
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• 1997

The Thin films were obtained by plasma polymerization of phenyl isothiocyanate. Polymerizations were carried out in rf(13.56 [MHz]) glow discharge generated in an inter-electrode capacitively coupled gas flow system. It was fecund that this monomer produces uniform films with a wide range of thicknesses, from hundreds of nanometers to tens of micrometers. The deposition rate appeared to be dependent on the substrate distance from the monomer inlet. The IR data revealed significant decrease in -NCS groups content in the polymer as compared with the monomer spectrum and indicated for the appearance of new absorption bands corresponding to the -CN and C-H aliphatic groups. The soluble fraction by GC was found to be composed of numerous low molecular-weight compounds.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.103-106
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• 2008

본 연구에서는 발사체 비행 중 가속도의 변화로 발생하는 엔진 입구압력의 변화를 고려하여 엔진의 구성품에 미치는 영향을 고찰하였고 그에 따른 엔진 성능 변화를 예측하였다. 엔진의 입구압은 탱크 내의 추진제 수두와 가압 압력 및 압력 손실 등으로 정의되며 이에 따라 발사체가 비행하면서 추진제 소모와 가속도 변화에 의해 입구압력이 변하게 된다. 입구압이 변할 때 펌프 토출압이 변하고 그에 따른 유량 변화로 가스발생기의 압렵변화가 발생하며, 이는 터빈의 출력변화로 이어져 다시 펌프의 토출압 변화로 나타남을 알 수 있었고, 이는 궁극적으로 주연소실의 연소압 변화를 이끌면서 엔진의 성능이 변화함을 알 수 있었다.

• 한국환경과학회지
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• 제22권3호
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• pp.269-279
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• 2013

In this paper, an environmental assessment was carried out on the whole process of industrial business activities to establish a basic plan for climate change mitigation and energy independency. The whole process was divided into each discharge process in terms of water, air, solid waste, green house gases and refractory organic compounds. The flowcharts and basic unit of process were analysed for three years (2008-2010), being utilized as basic information for the life cycle assessment. It was found that the unit loading for the whole process significantly depends on changes in the operation rate change and highly concentrated wastewater inflow. About 35% of solid waste production was reduced by improving the incineration method with co-combustion in coal boiler, generating about 57% of electricity used for the whole process, and consequently reducing the energy costs. As the eco-efficiency index was found to be more than 1, compared to the previous years, it can be said that improvement in general has taken place.