• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.245-246
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• 2008

고밀도 트렌치 공정을 위해 HBr 가스를 주로하고 $CF_4$, $SiF_4$, $NF_3$, He-$O_2$ 등을 첨가 가스로 이용하여 트렌치 공정을 하였다. 트렌치 공정시 첨가가스 비에 따라 트렌치 형상이 다양하게 되었다. 이러한 형상은 트렌치 소자 제조시 트렌치 내부를 채울 경우 여러 가지 어려움이 발생되는데, 특히 트렌치 내부가 잘 채워지지 않고 void가 생길 경우 소자의 신뢰성에 많은 영향을 미칠 수 있다. 본 연구에서는 고밀도 트렌치를 병렬로 형성한 후 형성된 트렌치 내부를 잘 채울수 있는 고밀도 트렌치 공정을 연구하였다. 트렌치 형성시 HBr을 주가스로 하고, $NF_3$, $CF_4$, $SiF_4$ 를 비율을 각각 59:27:7:7로 했을 때 수십만 트렌치 형성 각도가 약 $89^{\circ}$로 매우 좋은 형상을 얻었다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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• pp.126-131
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• 2011

Cyclone, a type of particle collector widely used in the field of ambient sampling and industrial particulate control, is the principal type of gas-solids separator that uses a centrifugal force. The goal of this study is to design and evaluate the cyclone that can be used for the household vacuum cleaners. A multi cyclone with a 1st cyclone and several 2nd cyclones is designed to improve dust collection efficiency. The dust collection efficiency and the suction power of 1st cyclone are evaluated. And the dust collection efficiency and the suction power of multi cyclone are evaluated according to various sizes of inlet and vortex finder. As a result, a cone shape porous filter has better dust collection efficiency than a cylinder shape porous filter. The dust collection efficiency of a multi cyclone is 3.5% greater than that of a single cyclone.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2214-2216
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• 2005

This paper is researched discharge and ozone generation characteristics of ozonizer using $Al_2O_3$ Ceramic dielectric. The discharge characteristics with variation of the discharge electrode area is studied. The characteristics of ozone concentration. ozone generation and ozone yield were measured to discharge power, discharge electrode area and supplied gas flux for oxygen and air. The solubility of ozone for water concentrations and ozone generations proportional to discharge power and discharge electrode area. Ozone yield has slowly increase with Increasing discharge power at high flow-rate. As the result, the maximum values of ozone characteristics ozone generation and ozone yield, can be obtained 5817[ppm] and 36[g/kWh]. We make enough the ozone concentration as the air in the home. An electric discharge electrode area is apt to shrink gradually into a miniaturization trend of the ozonizer but the enlargement of the occurrence flight of the electric discharge area gives the characteristic enhance the aid in the identity condition through the structure improvement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.408-411
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• 2003

Al doped Zinc Oxide(ZnO:Al) films, which is widely used as a transparent conductor in optoelectronic devices such as solar cell, liquid crystal display, plasma display panel, thermal heater, and other sensors, were prepared by using the capacitively coupled DC magnetron sputtering method. The influence of the substrate temperature, working gas pressure, discharge power and doping amounts of Al on the electrical, optical and morphological properties were investigated experimentally. The effect of bias voltage on the electrical properties of ZnO thin film were also studied. Films with lowest resistivity of $5.4{\times}10^{-4}\;{\Omega}-cm$ have been achieved in case of films deposited at 1mtorr, $400^{\circ}C$ with a substrate bias of +10V for 840nm in film thickness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.356-357
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• 2006

Tin oxide thin films have been prepared on display glass from mixtures of dibutyl tin diacetate as a tin source, oxygen as an oxidant by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. The relationships between the properties of tin oxide thin films and various reaction parameters such as the deposition temperature, deposition time and the oxygen gas flow rate were studied. As the deposition temperature increased, the texture plane of $SnO_2$ changed from (200) plane to denser (211) and (110) planes. Lower deposition temperature and thinner thickness of deposited film led to decreasing grain size, surface roughness and electrical resistivity of the formed thin films at $325{\sim}425^{\circ}C$. The properties of fabricated $SnO_2$ films are highly changed with variations of substrate temperature and deposition time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.169-170
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• 2007

In this paper we report upon an investigation into the effect of sputter pressure and RF power on the electrical properties of Gallium doped zinc oxide (GZO) film. GZO films were deposited on glass substrate without substrate temperature by RF magnetron sputtering from a ZnO target mixed with 5 wt% $Ga_2O_3$. Argon gas pressure and RF power were in the range of 1~11 mTorr, and 50~100 W, respectively. However, the resistivity of the film was strongly influenced by the sputter pressure and RF power. We were able to achieve as low as $1.5{\times}10^{-3}\;{\Omega}cm$, without substrate temperature.

• Journal of the Korean Vacuum Society
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• v.12 no.4
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• pp.228-234
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• 2003

The velocity of gadolinium(Gd) atomic vapor vaporized by an electron beam was measured by a microbalance. The velocity of about 900 ㎧ was obtained at an evaporation surface temperature of 2400-2500 K. The measured value was approximately 100 ㎧ faster than the maximum velocity of an ideal monatomic gas in an adiabatic expansion. This phenomenon can be explained that the internal energy of Gd atoms populated in higher excited levels at the high temperature should be convened to kinetic energy during adiabatic expansion. The calculated velocity agrees with the measured one when 100 excited energy levels are included in an enthalpy term for the velocity calculation. The characteristics of vapor flow as a function of heated surface temperature are also reported.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.794-799
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• 2008

The effect of ultrasonication on the sulforaphane analysis in cruciferous vegetables was investigated by GC/MS. The ultrasonication of the analysis samples was carried out in dichloromethane as a solvent, which was followed by concentration in nitrogen gas, and the analysis of sulforaphane was performed using selective ion monitoring (SIM) at m/z 72, 160, 55 and 114. The content of sulforaphane was the highest in the extract of broccoli (149 ppm), and followed by cabbage (67.9 ppm) and radish (35.4 ppm). When the vegetable samples were shaked after ultrasonication, the extraction efficiency of sulforaphane was 2.7-fold enhanced, compared to the extraction by shaking. The result suggested that pretreatment including sonication can be used fer improving the extraction efficiency of sulforaphane.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.4
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• pp.16-24
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• 2013

The analysis of performance and internal flow according to various numerical models for interior ballistics has been conducted. The initial flow has been mainly affected by the drag model of propellants and their drag degradation reduces oscillations of differential pressure between the breech and the shot base. Models of Nusselt number haven't influenced the major performance of interior ballistics. The negative differential pressure isn't generated in the case without the heat transfer of propellants.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.105-113
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• 2013

A numerical model of the igniter for the interior ballistics has been developed by combining lumped parameter model with the theoretical equation of orifice. With the developed model of the igniter, the numerical study on characteristics of the interior ballistics has been conducted according to the igniter configuration in terms of igniter length, side hole diameter, and distribution of side holes. As results of the calculation of the pressure difference between the breech and shot base, the low-cycle oscillations have been influenced by the igniter length, while the high-cycle oscillations have been affected by the side hole diameter and the distribution of side holes.