• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5758-5762
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• 2014

Electrostatically-actuated Micro device have been used widely in a variety of integrated sensors and actuators. Electrostatically-actuated micro devices with a gap of several micrometers or less between the electrodes have shown failure problems by electrostatic adhesion. To improve this adhesion phenomenon, micro devices of varying lengths and widths in electrodes were fabricated, and an alumina coating was then deposited using atomic layer deposition technology. The effects of improving adhesion phenomenon were compared by measuring the pull-in voltage before and after the coating process. The pull-in voltage increased with increasing length of the upper electrode after the coating. An increase in the electrode area results in an increase in the pull-in voltage after coating. The alumina coating method applied to improve the adhesion on an electrostatically-actuated micro device was observed as an effective method.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.95-102
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• 2022

Since the organic light-emitting diodes (OLEDs) have been widely investigated as next-generation displays, it has been successfully commercialized as a flexible and rollable display. However, there is still wide room and demand to improve the device characteristics such as power efficiency and lifetime. To solve this issue, there has been a wide research effort, and among them, the internal and the external light extraction techniques have been attracted in this research field by its fascinating characteristic of material independence. In this study, a micro-nano composite structured external light extraction layer was demonstrated. A reactive ion etching (RIE) process was performed on the surfaces of hexagonally packed hemisphere micro-lens array (MLA) and randomly distributed sphere diffusing films to form micro-nano composite structures. Random nanostructures of different sizes were fabricated by controlling the processing time of the O₂ / CHF₃ plasma. The fabricated device using a micro-nano composite external light extraction layer showed 1.38X improved external quantum efficiency compared to the reference device. The results prove that the external light extraction efficiency is improved by applying the micro-nano composite structure on conventional MLA fabricated through a simple process.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.219-229
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• 2022

In this study, we propose a miniaturized micro-ceramic heater device. After screen-printing a silver paste between pre-sintered two aluminum oxide plates to integrate a heating circuit, the device was fabricated through a low-temperature sintering process. In order to configure the optimal heating circuit integration condition, the output current evaluation and heating test were performed according to the number of screen prints of the silver paste at various voltages. A silver paste-based heating circuit printed with a line width of 200 ㎛ and a thickness of 60 ㎛ was successfully integrated on a pre-sintered alumina substrate through a low-temperature sintering process. In the case of the 5 times printed device, the thermal response showed a response rate of 18.19 ℃/sec. To demonstrate feasibility of the proposed device in the medical field, such as bio-tissue suturing and hemostasis, a voltage was applied to pig tissue in the device to test tissue change due to heat generated from the device. These results show the possibility that the proposed small ceramic heater could be used in the medical field based on its excellent temperature response.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.138-143
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• 2010

This paper presents the analysis, the fabrication and the test results of a micro passive gas pressure regulator to keep the outlet pressure costant even for a widely-varying inlet pressure. This device is to regulate the outlet pressure according to the applied reference pressure based on the pressure balancing mechanism of the structure including a membrane and a valve. This regulator consists of four layers; a bulk-micromachined silicon substrate, a sandblasted glass substrate, a PDMS valve seat layer and a glass valve layer. The device size is $10\times13\times1.7 mm3$. The device was fabricated by micromachining. The characteristic of the device was analyzed and tested. The characteristic of the fabricated pressure regulator is similar to that obtained from the analysis. The pressure regulator of this paper is feasible for portable systems and miniature drug delivery systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2249-2254
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• 2008

A non-thermal micron size plasma needle is applicable for medical treatment because it includes radicals, charged particles, ultraviolet emission, and strong electric fields. The electric fields around the plasma needle device driven by a radio frequency wave are investigated in order to calculate the power delivered to the cell. A commercial multi-physics code, CFD-ACE, was utilized for the calculation of electric fields for the optimization of the needle structure. The electric field and energy absorption profiles are presented with the variation of the device structure and the distance between the needle and tissues. The living tissues effectively absorb the radio frequency power from the plasma needle device with the covered pyrex structure.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.385-386
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1202-1205
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• 2005

Micro hole is one of basic elements for micro device or micro parts. By micro ECM, micro holes less than $50\mu{m}$ in diameter can be machined easily. Machining characteristics of micro ECM were investigated according to machining conditions such as electrolyte concentration and pulse conditions. From the investigation, optimal machining conditions were suggested for micro ECM of stainless steel. For the micro machining with high resolution, the change of machining gap should be predicted. By using electrochemical principle equations, the change of machining gap was simulated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.663-664
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• 2006

In the electronic, medical, aerospace and automobile industries, many products and parts are manufactured by joining. Recently, as these get smaller, micro joining is becoming more and more important. In this study, micro wire-to-micro wire parallel joining was performed using single mode fiber laser. Maximum power of the fiber laser is 100 W. The CCD(Charge- Coupled Device, CCD) camera to observe the specimen was made up. The objective was applied to micro joining system to make a small spot size of laser beam. In order to control the target position, micro-multi-axis-stage was set up. This paper presents results for the single mode fiber laser joining of micro wires.

• The Magazine of the IEIE
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• v.24 no.10
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• pp.63-72
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• 1997

Application of MEMS to biologic system mainly categorized into bio-electronics and micro-medical systems, Bio-electronics concerns on the biocompatible electronic device, in-vivo sensors, the sensors based on biological materials, biological materials for electronics and optics, the concepts and materials Inspired by biology and useful for electronics, the algorithm inspired by biology, artificial sense, and the biologic-inorganic hybrids. Micro-medical systems are utilited into the drug delivery systems, micro patient monitoring systems, micro prosthesis and artificial organs, cardiology related prothesis, analysis systems, and the minimal invasive surgery tools based on the m icrom achining technology.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.312-312
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• 2011

All ship's ballast water should be inspected by administration after enter into force IMO BWM Convention. The purpose of the sampling device is to concentrate large amount of samples and to improve return rate of samples. It is composed of Concentration and Rinsing Part and optimized by the variety of tests. it is fully automated and therefore efficiently operated in ships.