• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.63-68
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• 2015

Recently, 3D printer technologies have been used in many research efforts for high precision manufacturing. In particular, the rapid prototyping technology has been developing rapidly, because it can be manufactured in a short time with a 3D designed shape. This paper relates to the production characteristics of the straight bevel gear designed using a 3D print using the PolyJet method. The characteristics of a 3D printed straight bevel gear were compared with a machined straight bevel gear. The accuracy of the produced straight bevel gear was evaluated by backlash, meshing pattern, face angle, root angle, and surface roughness.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1501-1502
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• 2011

In this paper, an investigation of the 8" process for Trench Power MOSFET Application and Trench MOSFETs and its impact on device performance is presented. Layout dimensions of trench power MOSFETs have been continuously reduced in order to decrease the specific on-resistance, maintaining equal vertical dimensions. We discuss experimental results for devices with a pitch size down fabricated with an unconventional gate trench topology and a simplified manufacturing scheme. The fabricated Trench MOSFETs are observed the trench gate oxidation by SEM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2230-2234
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• 2010

This paper deals with the change of surface potential decay, surface resistivity, contact angle and XPS of ultraviolet-treated PET films. From the experimental results on the surface potential decay of UV degraded-samples, it was found that the accumulation of charge is decreased and the surface potential decay time is shortened. Also, from the result of XPS, it was found that the changes affected by the surface degradation of PET film were caused by the generation of carboxyl groups through the chain decomposition and recombination with oxygen molecules in the air.

• Polymer(Korea)
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• v.34 no.6
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• pp.553-559
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• 2010

The paper describes the preparation and characterization of conductive polyaniline-modified polymers by growing of aniline onto functionalized poly(styrene-co-p-methylstyrene) [P(St-co-MSt)]. For this purpose, P(St-co-MSt) was synthesized via nitroxide mediated radical polymerization (NMRP) and then N-boromosuccinimide was used for introduction of bromine to the benzylic positions of copolymer. Afterwards, 1,4-phenylenediamine was linked to the brominated P(St-co-MSt) and functionalized copolymer $[P(St-co-MSt)-NH_2]$ was prepared. The graft copolymerization of aniline monomers onto functionalized P(St-co-MSt) was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-toluenesulfonic acid-doped PANI was chemically grafted onto P(St-co-MSt) via oxidation polymerization. The obtained terpolymer was studied by FTIR and UV-Vis spectroscopy and its thermal behaviour were examined by DSC and TGA analyses. The conductivity of terpolymer was measured by four-point probe method and electroactivity was measured by cyclic voltammetry (CV). The solubility of P(St-co-MSt)-g-PANI was examined in common organic solvents.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.89-92
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• 2009

In this paper, We observed degradation of general poly-cristalline silicon solar cell by light and heat. This is very important to define solar cell's characteristics. So we test eight cells that made of poly-cristalline silicon. We expect to the result of this experiment is useful for researching and measuring solar cell's characteristics.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.75-80
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• 2000

This paper deals with the precision cutting characteristics of mono-crystal diamonds poly-crystal diamonds and tungsten carbide tool on ductile material. The cutting tests were carried out under various uncut chip areas and 20${\mu}{\textrm}{m}$ depth of engagement. The machinability in precision machining was discussed from the viewpoints of the normal cutting forces and the surface roughness of the workpiece. As the feed rate decreases the normal force difference for cutting edge radii appears to large. In various cutting edge radii the surface roughness difference when cut the copper which is ductile material than the aluminium alloy is large. As the same cutting condition the hardness value on cut surface with the diamond tool appears to be smaller than that of the tungsten carbide tool.

• Structural Monitoring and Maintenance
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• v.4 no.2
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• pp.107-113
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• 2017

In this paper, we present a strain-sensitive composite skin-like film made up of piezoresistive zinc oxide (ZnO) nanorods embedded in a flexible poly(dimethylsiloxane) substrate, with added reduced graphene oxide (rGO) to facilitate connections between the nanorod clusters and increase strain sensitivity. Preparation of the composite is described in detail. Cyclic strain sensing tests are conducted. Experiments indicate that the resulting ZnO-PDMS/rGO composite film is strain-sensitive and thus capable of sensing cycling strain accurately. As such, it has the potential to be molded on to a structure (civil, mechanical, aerospace, or biological) in order to provide a strain sensing skin.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.1001-1003
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• 1998

In this paper, $Ar^+$ ion laser etching process of single/poly crystalline silicon with $CCl_{2}F_{2}$ gas is studied for MEMS applications. To investigate the effects of process parameters, laser power, gas pressure, scanning speed were varied and multiple scanning was carried out to obtain high aspect ratio. In addition, scanning width was varied to observe the trench profile etched in repeating scanning cycle. From the etching of $2.6{\mu}m$ thick polycrystalline Si deposited on insulator, trench with flat bottom and vertical side wall was obtained and it is possible to apply this results for MEMS applications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.251-257
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• 2010

In this paper, we propose modified algorithm of motion vector detection for the pixel of image in the optical sensor. It is designed to reduce the amount of operation and have more accuracy in the motion detection than previous block matching algorithm. The proposed algorithm is implemented with Cyclone and fabricated using SEC 0.35um CMOS 1-poly-4-metal technology. The result of test with CARTESIAN ROBOT meets the desired performance.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.529-532
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• 2010

Multi-carrier demultiplexer/demodulator (MCDD) in an on-board processing (OBP) satellite used for digital multimedia services has two typical architectures according to the channel demultiplexing procedure: Multistage multi-carrier demultiplexer (M-MCD) or poly-phase fast Fourier transform (PPF). During the channel demultiplexing, phase and quantization errors influence the performance of MCDD; those errors affect the bit error rate (BER) performance of M-MCD and PPF differently. In this paper, we derive the phase error variances that satisfy the condition that M-MCD and PPF have the same signal to noise ratio according to quantization bits, and then, with these results, analyze the BER performances of M-MCD and PPF. The results provided here may be a useful reference for the selection of M-MCD or PPF in designing the MCDD in an OBP satellite communications system.