• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.255-259
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• 2001

The spring constant of a micro coil spring was measured by uniaxial tensile test. The inner diameter of it is $35{\mu}m$ and the pitch size is about $23{\mu}m$. A suing constant measurement system was developed. It consists of control units, load cell units, linear stages and several specially designed jigs and fixtures. Load and displacement are measured using a commercial load cell of 1000g capacity and a magnetic scale of $0.5{\mu}m$ resolution. In this study, a method to measure the spring constant of micro coil spring is presented and the relationship between misalignment of specimen and measurement error is discussed.

• ETRI Journal
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• 제24권5호
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• pp.333-340
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• 2002

We propose a new process technique for fabricating very high-density trench MOSFETs using 3 mask layers with oxide spacers and a self-aligned technique. This technique reduces the device size in trench width, source, and p-body region with a resulting increase in cell density and current driving capability as well as cost-effective production capability. We were able to obtain a higher breakdown voltage with uniform oxide grown along the trench surface. The channel density of the trench DMOSFET with a cell pitch of 2.3-2.4 ${\mu}m$ was 100 Mcell/$in^2$ and a specific on-resistance of 0.41 $m{\Omega}{\cdot}cm^2$ was obtained under a blocking voltage of 43 V.

• Journal of Advanced Marine Engineering and Technology
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• 제23권1호
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• pp.19-24
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• 1999

In this paper the emission characteristic of the ship's diesel engine with CPP(Controllable Pitch Propeller) were investigated under the passage test on the sea. As the results it is confirmed that the NOx.$CO_x$ concentrations increase as the engine speed increases and the torque decreases. but the amount of NOx, COx emissions(g./k Wh) decrease as the torque increase regardless of the engine speed. Also it is compared with the NOx concentra-tions measured by the two method-ECC(Electrochemical Cell)and CLD(Chemiluminescence Detector)for the correct measurement and the ECC indicated higher value than the CLD.

• 한국전기전자재료학회논문지
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• 제16권10호
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• pp.853-858
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• 2003

In this study, a new simplified technology for fabricating high density trench gate DMOSFETs using only three mask layers and TEOS/nitride spacer is proposed. Due to the reduced masking steps and self-aligned process, this technique can afford to fabricate DMOSFETs with high cell density up to 100 Mcell/inch$^2$ and cost-effective production. The resulting unit cell pitch was 2.3∼2.4${\mu}$m. The fabricated device exhibited a excellent specific on-resistance characteristic of 0.36m$\Omega$. cm$^2$ with a breakdown voltage of 42V. Moreover, time to breakdown of gate oxide was remarkably increased by the hydrogen annealing after trench etching.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.854-857
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• 2009

The concept of a microplasma current switch for a device operated in a current mode like organic light-emitting diodes, which features matrix addressability and current switching, is presented as well as its architecture and operational principle. To verify the concept, we have fabricated a 100 mm ${\times}$ 100 mm microplasma current switch panel with a cell pitch of $1080{\mu}m{\times}1080{\mu}m$. Moreover, the current-voltage measurements of the unit cell are performed for three different driving voltage amplitudes. They show the characteristic of an asymmetric floating double probe diagnosing plasmas.

• Carbon letters
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• 제9권1호
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• pp.28-34
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• 2008

Multidirectional reinforcement is aimed primarily at overcoming interlaminar weakness, hence a major interest lies in the mechanical properties of multidirectional carbon/carbon composites. Mechanical properties depend on the type of carbon fiber, the size of the fiber bundle, the spacing of the bundles, the angles of the bundles relative to the axes of the block, and matrix formation. In the present studies, PAN based carbon fiber preforms manufactured different size of unit cell have been prepared. Densification of these used high pressure infiltration and carbonization technique with coal tar pitch as matrix precursor was carried out. Scanning electron microscopy has been used to study the fracture behavior of composites. The size of unit cell of the preforms has considerably affected on the flexural properties as well as microstructure of the carbon/carbon composites.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.433-433
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• 2010

A microplasma current switch (MPCS) for a device operated in a current mode like organic light-emitting diodes (OLEDs), which features matrix addressability and current switching, is presented as well as its architecture and operational principle. The MPCS utilizes the intrinsic memory and conductivity of plasmas to achieve matrix addressability and current switching. We have fabricated a $100\;mm\;{\times}\;100\;mm$ MPCS panel in which its cell pitch is $1080\;{\mu}m\;{\times}\;1080\;{\mu}m$. The matrix addressability and current switching were verified. In addition, the current-voltage (I-V) characteristic of the unit cell was measured when plasmas were ignited. In principle, the scheme of the MPCS is equivalent to that of a double Langmuir probe diagnosing plasma parameters except for their relative dimensions to a plasma volume. Accordingly, the I-V characteristic was analyzed by a double Langmuir probe theory, and the plasma density and electron temperature were estimated from the I-V curve using a collisional double Langmuir probe theory.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.652-655
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• 2009

The bimodal porous carbons were synthesized by using imprinting method with templates of SBA-15 particle and silica sphere and applied as supporting materials for the electro-catalyst of polymer electrolyte fuel cell (PEFC). The silica spheres with diameter size of 100 nm and SBA-15 particle having 200 nm -250 nm diameter and 700 nm -900 nm length were synthesized in this work. The bimodal porous carbons (S100) were prepared by using the silica spheres and SBA-15 as templates and mesophase pitch as a carbon source. The PtRu nanoparticle of ca. 1.9 nm were supported on the bimodal porous carbon support and the resulting PtRu/S100 catalysts was tested by the cyclic voltammetry. The use of bimodal porous carbon showed in comparable electro-catalytic activities with commercial catalyst. Though unclear effects of bimodal porosity of supports could be obtained in the scope of this study, morphological advantage in electrical conductivity can be considered on the electro-catalytic activity.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.123.1-123.1
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• 2017

Hybrid solar cells have intensively studied in recent years due to their advantages such as cost effectiveness and possibility of applications in flexible and transparent devices. It is critical to fabricate individual layer composed of organic and inorganic materials in the hybrid solar cell at low cost. Therefore, it is required to manufacture cheaply and enhance the photon-to-electricity conversion efficiency of each layer in the flexible solar cell industry. In this research, we fabricated pure Cu metal mesh electrode prepared by using electroplating and/or electroless plating on the Ni mold which was manufacture through photolithography, electroforming, and polishing process. Copper mesh was formed on the surface of nickel metal working master when pulsed electrolytic copper deposition were performed at various plating parameters such as plating time, current density, and so on. After electrodeposition at 2ASD for 5~30seconds, the line/pitch/thickness of copper mesh sheet was $1.8{\sim}2.0/298/0.5{\mu}m$.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.112.1-112.1
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• 2011

The back contact solar cell (BCSC) has several advantages compared to the conventional solar cell since it can reduce grid shadowing loss and contact resistance between the electrode and the silicon substrate. This paper presents the effect of the surface texturing of the silicon BCSC by varying the texturing depth or the texturing gap in the commercially available simulation software, ATHENA and ATLAS of the company SILVACO. The texturing depth was varied from $5{\mu}m$ to $150{\mu}m$ and the texturing gap was varied from $1{\mu}m$ to $100{\mu}m$ in the simulation. The resulting efficiency of the silicon BCSC was evaluated depending on the texturing condition. The quantum efficiency and the I-V curve of the designed silicon BCSC was also obtained for the analysis since they are closely related with the solar cell efficiency. Other parameters of the simulated silicon BCSC are as follows. The substrate was an n-type silicon, which was doped with phosphorous at $6{\times}10^{15}cm^{-3}$, and its thickness was $180{\mu}m$, a typical thickness of commercial solar cell substrate thickness. The back surface field (BSF) was $1{\times}10^{20}\;cm^{-3}$ and the doping concentration of a boron doped emitter was $8.5{\times}10^{19}\;cm^{-3}$. The pitch of the silicon BCSC was $1250{\mu}m$ and the anti-reflection coating (ARC) SiN thickness was $0.079{\mu}m$. It was assumed that the texturing was anisotropic etching of crystalline silicon, resulting in texturing angle of 54.7 degrees. The best efficiency was 25.6264% when texturing depth was $50{\mu}m$ with zero texturing gap in case of low texturing depth (< $100{\mu}m$).