• Journal of Digital Convergence
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• v.16 no.9
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• pp.39-49
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• 2018

The research investigates the changes of current government policy for Micro-enterprises with respect to the government policy fund, start-up, management education and the relevant consulting services. The examination is used for providing the improving directions of Micro-enterprise government policy reflecting on the current Micro-enterprises. While Micro-enterprise belongs to the class of Small enterprise, the impact of the government policies in Micro-enterprise is much bigger than the other. For this reason, the fundamental investigation considering Micro-enterprise is crucial. In order to provide the improving directions, this research examines the incumbent government policies. Then, the analyses provides the changing agenda for Micro-enterprise. The suggestions contributes to the improving criteria for right paradigm of Micro-enterprise.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1059-1064
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• 2001

This study Investigates the effect of the wave form of pulse energization on the collection characteristics of a wide plate spacing electrostatic precipitator. For the semi-pulse energization, the peak current and voltage of the energization increases with increase of the pulse period, and the corona current increases, as pulse ratio decreases. For the micro-pulse energization, the corona current increases with increase of the pulse voltage. The collection efficiency of semi-pulse and micro-pulse energization is larger than that of DC charge.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.225-228
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• 2007

Micro solid propellant thruster is the most feasible for development with current MEMS. Basic components of micro solid propellant thruster are diverging nozzle, micro igniter, combustion chamber, and solid propellant. Micro nozzles and micro chambers were fabricated using photosensitive glass by anisotropic wet etching technique. Micro Pt heaters on glass membrane which ignited solid propellant were developed. Components of thruster were integrated. Successful ignition was observed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1148-1153
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• 2006

This paper deals with the effect of the direct heating method(DHM) for straightening the micro wire. Straightened micro wires have been widely used in the fields of the medicine and the semi-conductor. We have developed a micro wire straightening system by using the direct wire heating method. To controling the tension of the micro wire during the heating and straightening process, a precision tension sensor was set up. In order to avoid the surface oxidation during the heating process, the argon inert gas was supplied to the vicinity of the wire. And, this paper shows the correlation between the tension and the current when arson gas supplied to the tungsten wire. Through several experiments, the optimal tension and current were found. Also, higher straightness $({\approx}1{\mu}m/1000{\mu}m)$ and roundness$(<{\Phi}{\pm}2{\mu}m/100{\mu}m)$ founded when $500{\mu}600gf$ tension and 1.5 ampere.

• Korean Journal of Materials Research
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• v.21 no.11
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• pp.581-586
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• 2011

This study describes a hydrogen embrittlement evaluation of the subsurface zone in 590DP steel by micro-Vickers hardness measurement. The 590DP steel was designed to use in high-strength thin steel sheets as automotive materials. The test specimens were fabricated to 5 series varying the chemical composition through the process of casting and rolling. Electrochemical hydrogen charging was conducted on each specimen with varying current densities and charging times. The relationship between the embrittlement and hydrogen charging conditions was established by investigating the metallography. The micro-Vickers hardness was measured to evaluate the hydrogen embrittlement of the subsurface zone in addition to the microscopic investigation. The micro-Vickers hardness increased with the charging time at the surface. However, the changing ratio and maximum variation of hardness with depth were nearly the same value for each test specimen under the current density of 150 mA/$cm^2$ and charging time of 50 hours. Consequently, it appears that hydrogen embrittlement in 590DP steel can be evaluated by micro-Vickers hardness measurement.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1459-1462
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• 2007

In general a thermoelectric cooler (TEC) consists of a series of P type and N type thermoelectric materials sandwiched between two wafers. When a DC current passes through these materials, three different effects take place; Peltier effect, Joule heating effect and heat transfer by conduction due to temperature difference between hot and cold plates. In this study we have developed a micro TEC using $Bi_2Te_3$ (N type) and $Bi_{0.5}Sb_{1.5}Te_3$ (P type) thin films. In order to improve that performance of a micro TEC, we made 10 um height TE legs using special PR only for lift-off. We measured COP (coefficient of performance) and temperature difference between hot and cold connectors with current.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.451-454
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• 2002

In this paper, studied on the one-chip design of low cost for the micro-stepping drive having 5-phase Pentagon Type winding. Micro-stepping method in order to eliminate effectively the resonant phenomena and to Increase the positional resolution. This paper proposed trapezoidal current wave- form for current control and provided design- method by using only one-chip of low cost. Therefore the drive will be simple and small size. Also the drive will have a lot of advantage at commercial business. Finally the above study has been implemented on the VHDL. Simulation has been performed to verify the PWM for micro-stepping drive.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.43-51
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• 2010

Speed, accuracy and smoothness are the important properties of pan-tilt camera. In the case of a high ratio zoom lens system, low vibration characteristic is a crucial point in driving pan-tilt mechanism. In this paper, a novel micro-stepping controller with a function of reducing vibration was designed using field programmable gate arrays (FPGA) technology for high zoom ratio pan-tilt camera. The proposed variable reference current (VRC) control scheme reduces vibration decently and optimizing coil current in order to prevent the step motor from occurring missing steps. By employing VRC control scheme, the vibration in low speed could be significantly minimized. The proposed controller can also make very high speed of 378kpps micro-step driving, and increase maximum acceleration in motion profiles.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.83-88
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• 2004

Micro wires manufactured by the straightening progress are widely used in bio-medical and semi-conductor fields. In this study, we have developed a novel straightener which uses the direct heating method for straightening. In order to avoid the surface oxidization, during the heating process, we supplied the inert gas(Ar) and examined the effect of the gas flow rate. The effect of the tension and the current applied to the tungsten micro wires were thoroughly studied. From various experiments, it was found that when the tension is $500{\sim}600gf$ and the current is about 1.5A, we obtained higher straightness(${\approx}1{\mu}m/1000{\mu}m$) and roundness ($<{\pm}2{\mu}m/100{\mu}m$).

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.58-63
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• 2006

FIB equipment can perform sputtering and chemical vapor deposition simultaneously. It is very advantageously used to fabricate a micro structure part having 3D shape because the minimum beam size of ${\Phi}10nm$ and smaller is available. Since general FIB uses very short wavelength and extremely high energy, it can directly make a micro structure less than $1{\mu}m$. As a result, FIB has been probability in manufacturing high performance micro devices and high precision micro structures. Until now, FIB has been commonly used as a very powerful tool in the semiconductor industry. It is mainly used for mask repair, device correction, failure analysis, IC error correction, etc. In this paper FIB-Sputtering and FIB-CVD characteristic analysis were carried out according to $Ga^+$ ion beam current that is very important parameter for minimizing the pattern size and maximizing the yield. Also, for FIB-Sputtering burr caused by redeposition of the substrate characteristic analysis was carried out.