• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.86-89
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• 2004

One most feasible way to measure the concentration field in the micro-channel is using micro-LIF(Laser Induced Fluorescence) method. However, an accurate concentration field at a given cross plane in a micro-channel has not been successfully achieved so far due to various limitations in the light illumination and fluorescence signal detection. The present study demonstrates a novel method to provide an ultra thin laser sheet beam having five(5) microns thickness by use of a micro focus laser line generator. The laser sheet beam illuminates an exact plane of concentration measurement field to increase the signal to noise ratio and considerably reduce the depth uncertainty. Nile Blue A was used as fluorescent dye for the present LIF measurement. The enhancement of the fluorescent intensity signals was performed by a solvent mixture of water $(95\%)$ and ethanol (EtOH)/methanol (MeOH) $(5\%)$ mixture. To reduce the rms errors resulted from the CCD electronic noise and other sources, an expansion of grid size was attempted from $1\times1$ to 3(3 or 5(5 pixel data windows and the pertinent signal-to-noise level has been noticeably increased accordingly.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1540-1545
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• 2004

Measurement of concentration fields in a micro-channel is the crucial technology in the area of Lab-on-a-chip to be used for various bio-chemical applications. It is wel-known that the only possible way to measure the concentration field in the micro-channel is using micro-LIF(Laser Induced Fluorescence) method. However, an accurate concentration field at a given cross plane in a micro-channel has not been made so far due to the limit of light illumination. The present study demonstrates a novel method to provide an ultra thin laser sheet beam having 5 microns thickness by a micro focus laser line generator. Nile Blue A was used as fluorescent dye for LIF measurement. The laser sheet beam illuminates an exact plane of concentration measurement in the micro-channel to increase the signal to noise ratio and reduce the depth uncertainty considerably.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.383-386
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• 1997

Electrostatic suspension is a method to levitate an object by using electrostatic forces. Its main advantage is to levitate objects without any mechanical contact which fulfills the requirement of an object handling in ultra clean environment. In this paper, the electrostatic suspension system for film-like thin plate such as aluminum sheet, is designed and controlled. In contrast with the conventional electrostatic suspension system which requires the costly and bulky high-voltage amplifiers, it is suggested to use the switching voltage control method in consideration of real industrial application for the handling of such flexible bodies. Some experimental results show that the developed electrostatic suspension system shows good performances to levitate flexible film-like thin plate.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.383-386
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• 2008

Magnesium alloy sheets have been extending their field of applications to automotive and electronic industries taking advantage of their excellent light weight property. In addition to their excellent light property, magnesium alloys have several other advantages: high specific strength, good welding capability and corrosion resistance. Taking advantage of these benefits, magnesium alloys have also been substituting the polymeric materials in the electronic devices industries. In sheet metal forming application with magnesium alloys, the lower formability and high springback due to the lower elastic property (Young's modulus=45 GPa) at room temperature are major hurdles by which magnesium alloys have limited applications. In this study, commercial notebook case was adopted as the benchmark model, and then design parameters and process conditions are analyzed by the finite element simulation and physical try-outs.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.287-291
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• 2001

In this study, we designed and constructed a multi-forming progressive die with a bending, embossing on the multi-stage and performed through the try out. Out of the characteristics of this paper that nothing might be ever seen before such as this type of research method on the all of processes of thin and high precision production part.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.95-97
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• 2004

We studied a low temperature ion doping process for poly-Si Thin Film Transistor (TFT) on plastic substrates. The ion doping process was performed using an ion shower system, and subsequently, excimer laser annealing (ELA) was done for the activation. We have studied the crystallinity of Si surface at each step using UV-reflectance spectroscopy and the sheet resistance using 4-point probe. We found that the temperature has increased during ion shower doping for a-Si film and the activation has not been fulfilled stably because of the thermal damage against the plastic substrate. By trying newly a pulsed ion shower doping, the ion was efficiently incorporated into the a-Si film on plastic substrate. The sheet resistance decreased with the increase of the pulsed doping time, which was corresponded to the incorporated dose. Also we confirmed a relationship between the crystallinity and the sheet resistance. A sheet resistance of 300 ${\Omega}$/sq for the Si film of 50nm thickness was obtained with a good reproducibility. The ion shower technique is a promising doping technique for ultra low temperature poly-Si TFTs on plastic substrates as well as those on glass substrates.

• Corrosion Science and Technology
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• v.23 no.4
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• pp.302-309
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• 2024

The purpose of this study was to elucidate effects of a thin (tens to hundreds of nanometers) Ni-flash coating layer on hydrogen embrittlement (HE) and liquid metal embrittlement (LME) in ultra-high-strength electrogalvanized steel with a tensile strength of more than 1 GPa. Various experimental and analytical methods, including thermal desorption spectroscopy, slow strain rate testing, resistance spot welding, X-ray diffraction, and metallographic observation, were employed. Results showed that an increase in Ni target amount for flash coating resulted in a decrease in diffusible hydrogen content during electrogalvanizing, resulting in a significant decrease in HE sensitivity. Moreover, a Ni target amount of more than 1000 mg/m² drastically reduced the occurring frequency and average depth of LME. This reduction could be primarily attributed to formation of Zn-Ni intermetallic phases during the welding process that could inhibit liquefaction of intermetallic phases in the heat-affected zone. This study provides a desirable Ni target amount for Ni-flash coating on ultra-high-strength steels conducted in a continuous galvanizing line or a high-speed batch line to achieve high resistance to both HE and LME.

• Journal of the Korean institute of surface engineering
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• v.38 no.1
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• pp.28-36
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• 2005

In this study, the reflow characteristics of copper thin films which is expected to be used as interconnection materials in the next generation semiconductor devices were investigated. Cu thin films were deposited on the TaN diffusion barrier by metal organic chemical vapor deposition (MOCVD) and annealed at the temperature between 250℃ and 550℃ in various ambient gases. When the Cu thin films were annealed in the hydrogen ambience compared with oxygen ambience, sheet resistance of Cu thin films decreased and the breakdown of TaN diffusion barrier was not occurred and a stable Cu/TaN/Si structure was formed at the annealing temperature of 450℃. In addition, reflow properties of Cu thin films could be enhanced in H₂ ambient. With Cu reflow process, we could fill the trench patterns of 0.16～0.24 11m with aspect ratio of 4.17～6.25 at the annealing temperature of 450℃ in hydrogen ambience. It is expected that Cu reflow process will be applied to fill the deep pattern with ultra fine structure in metallization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.207-209
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• 2004

Currently, for satisfying the needs of scaled MOSFET's a high quality thin oxide dielectric is desired because the properties of conventional $SiO_2$ film are not acceptable for these very small sized transistors. As an alternative gate dielectric have drawn considerable alternation due to their superior performance and reliability properties over conventional $SiO_2$, to obtain the superior characteristics of ultra thin dielectric films, $N_2O$ grown thin oxynitride has been proposed as a dielectric growtuanneal ambient. In this study the authors observed process characteristics of $N_2O$ grown thin dielectric. In view points of the process characteristics of MOS capacitor, the sheet resistance of 4.07$[\Omega/sq.]$, the film stress of $1.009e^{10}[dyne/cm^2]$, the threshold voltage$(V_t)$ of 0.39[V], the breakdown voltage(BV[V]) of 11.45[V] was measured in PMOS. I could achieve improved electrical characteristics and reliability for deep submicron MOSFET devices with $N_2O$ thin oxide.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1112-1115
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• 2005

In this study, we performed excimer laser activation on Phosphorus or Boron doped a-Si (amorphous silicon) film. We've got a very low sheet resistance (Rs), Rs was 60 ohm/sq. with phosphorus doping and was 65 ohm/sq. with boron doping at each optimized laser irradiation condition. We've found Rs on activated thin film showed an unprecedented behavior in both cases, because Rs had a strong dependency on the crystallinity of the activated Si film.