• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.52-59
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• 2004

Recently, many researches for fine particles plasma have been focused on the fabrication of the new devices and materials in micro-electronic industry, although reduction or elimination of fine particles was interested in plasma processing until now on. In order to enhance their utilization, it is necessary to control and analyze fine particle behavior. Therefore, we developed simulation model of fine particles in RF Ar plasmas. This model consists of the calculation parts of plasma structure using a two-dimensional fluid model and of fine particle behavior. The motion of fine particles was derived from the charge amount on the fine particles and forces applied to them. In this paper, Ar plasma properties using two-dimensional fluid model without fine particles were calculated at power source voltage 15[V] and pressure 0.5[Torr]. Time-averaged spatial distributions of Ar plasma were shown. The process on the formation of Coulomb crystal of fine particles was investigated and it was explained by combination of ion drag and electrostatic forces. And also analysis on the forces of fine particles was presented.

• KSBB Journal
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• v.17 no.1
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• pp.49-53
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• 2002

The changes in the levels of $\gamma$ -aminobutyric acid (GABA) and some free amino acids were investigated in germinating brown rices. Ungerminated brown rices were germinated for 72 hrs by application of the following solutions: 1) distilled water, 2) 50 ppm lactic acid, 3) 5 mM glutamic acid. The GABA levels were enhanced in all germinated states of brown rices compared with ungerminated ones, highest in the germinated brown rices by 5 mM glutamic acid solution. Alanine levels were also enhanced significantly in the germinated brown rices. The levels of aspartic acid and glutamic acid were decreased significantly in all the germinated states. The levels of serine decreased during germination in the solutions of water and lactic acid were increased by the germination in the glutamic acid solution. The data show that germination of brown rices by the application of the glutamic acid solution can significantly increase the levels of GABA and can restore the serine level.

• Membrane Journal
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• v.27 no.6
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• pp.477-486
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• 2017

Hydrogen is one of energy storage systems, which could be transfer from electric energy to chemical energy or from chemical energy to electric energy, and is as an energy carrier. Water electrolysis is being investigating as one of the hydrogen production methods. Recently, water electrolysis receive attention for the element technology in PTG (power to gas) and PTL (power to liquid) system. In this paper, it was explained the principle and type for the water electrolysis, and recent research review for the alkaline water electrolysis.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.31-42
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• 2014

Purpose: The present study was conducted to investigate the effect of the physical properties of RGP lens induced by lens polishing on the actual wearer's subjective comfort, the tear film break-up time and the blinking rate as a follow-up study that revealed the relationship between the lens physical properties during lens manufacturing and lens wearer's factors. Methods: RGP lenses made from the three different polishing conditions (25, 50 and 100 seconds) were applied on 28 eyes of 17 subjects, aged 20 to 29 years, without any known disease and surgical history in the eyes. While the subjects were asked to wear the RGP lenses longer than a week, the questionnaire for the comfortability was administered everyday. Subjective and objective tear break-up time and blinking rate of the wearers were further measured. Results: The wearer's subjective comfortability showed some difference in the type of discomfort and satisfaction score according to the polishing status when wearing RGP lenses made from different polishing conditions longer than a week, and a bigger difference in satisfaction score induced by polishing condition was especially shown in experienced RGP lens wearer rather than un-experienced wearer. In the case of RGP lens wearer compared with the ones without the wearing experience, as the wearing time increased subjective and objective tear break-up time were increased and the blinking rate was decreased. However, subjective and objective tear break-up time were tended to decrease with even longer wearing time when wearing the RGP lens made from the polishment for 100 seconds. Conclusions: These results confirmed that the optimization of physical properties of the lens may not give the same effect on the wearer's subjective and objective symptoms and other factors when actual wearing. From the results, it can suggest that the success rate of RGP lens wear may be changed by physiological factors such as the stabilization of wearer's tear film, comfortability and lens wearing experience when wearing RGP lens based on 'The manufacturing standard for soft contact lens/hard contact lens' provided by Korea Food and Drug Administration.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.129-133
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• 2020

The concentration of remaining formaldehyde contained in waste liquid emitted from the process of urea-formaldehyde microcapsule synthesis was analyzed by gas chromatography-mass spectrometry (GC-MS). Three factors that can affect on the reaction of formaldehyde were selected including pH, ammonium chloride input and temperature. The effect of these factors on the concentration of remaining formaldehyde was studied. When ammonium chloride input was 0.025g, microcapsules could not be obtained or core substance leaked out because of weak shell, and therefore this reaction condition would be inadequate. It was confirmed that the concentration of remaining formaldehyde could be minimized when the microencapsulation was conducted at 70℃ and pH 2.5 by using a ammonium chloride input of 0.050g. This study can make contribution to UF microencapsulation in safer working environment.

• Journal of Korea Multimedia Society
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• v.14 no.10
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• pp.1262-1274
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• 2011

A fast and stable deformation model is essential for realistic simulation of image morphing. In order to stabilize deformation, we used two internal thin plate mass-spring systems that compute the displacements of the x- and y-components of all nodes on the mesh. The deformation results are globally smoother and more stable due to the direction limitation of thin plate mass-spring systems. One-to-one deformation is one of the important issues in image morphing. We focus on fast removing overlaps in the process of deformation. To rapidly remove overlaps, the external forces are set automatically on four or eight neighboring nodes. The speed of removing overlaps is faster when external forces are set on four or eight neighbouring nodes than when on two neighbouring nodes.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.350-354
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• 2010

In natural world various inorganic crystals are grown with controlled shape and size in hybrid forms with organics. Such natural processes have been attempted much to mimick artificially. One of the example is calcium carbonate which has been examined a lot in the field of biomineralization. In this study, we utilize well-organized surface of polydiacetylene(PDA) films as the crystal-growing template. We devised a novel mini-arrayer device that transfers PDA films at air/water interfaces of each array well and deposit them to hydrophobized glass substrates. This technical improvement will contribute to facilitate better understandings of biomineralization mechanism.

• Journal of the Korean Electrochemical Society
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• v.15 no.4
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• pp.256-263
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• 2012

This study was performed to investigate the separation of cesium cations by using an electrochemical ion exchanger of nickel hexacyanoferrate($KNiFe(CN)_6$) film electrode. Potential, current, and charge passing through the cyclic voltammograms were measured in singular and binary solutions of 1.0M $NaNO_3$ and 1.0M $CsNO_3$. Before and after each experiment, the structural morphology and atomic composition of $KNiFe(CN)_6$ were analyzed by SEM and EDS, respectively. The ion selectivity of $KNiFe(CN)_6$ was also observed by the voltammograms and atomic compositions measured in the solution alternated between sodium and cesium. As the result of this study, it was found that the electrically switched $KNiFe(CN)_6$ ion exchanger had the significant advantage of 40 times or longer durability than conventional organic or inorganic ion exchanger. It was also shown that the $KNiFe(CN)_6$ ion exchanger had high selectivity for cesium over sodium.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.504-508
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• 2010

The development of high voltage Insulated Gate Bipolar Transistor (IGBT) have given new device advantage in the areas where they compete with conventional GTO (Gate Turnoff Thyristor) technology. The IGBT combines the advantages of a power MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) and a bipolar power transistor. The change of electrical characteristics for IGBT is mainly coming from the change of characteristics of MOSFET at the input gate and the PNP transistors at the output. The change of threshold voltage, which is one of the important design parameters, is brought by charge trapping at the gate oxide under the environment that radiation exists. The energy loss will be also studied as the inductance values are changed. In this paper, the electrical characteristics are simulated by SPICE, and compared for variation of inductance and threshold voltage based on IGBT.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.639-644
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• 2015

A cylindrical secondary Li-ion cell is a device in which stored chemical energy is converted to electrical energy via an electrochemical reaction. These cells are widely used for applications that require high capacity and rate power, such as notebooks, power tools, and electric vehicles. The role of a center pin is to retain the channel for gas release, preventing blockage of the hollow of the jelly roll during a charge-discharge cycle, and to prevent an internal short circuit for tearing of separator under mechanical free fall. In this paper, two experiments are conducted with and without the center pin to experimentally verify the importance of the role of the center pin. The first experiment is a 50-cycle charge-discharge cycle test, and the second is a free fall test conducted according to the Underwriters Laboratories (UL) standards. Based on these experiments, we demonstrate that the center pin in a cylindrical cell is a very important component in terms of safety.