Hydrophobic Surface Treatment of Carbon Black Nanoparticles in Isopropyl Alcohol Solution Using He/SF₆ Atmospheric Plasma Jet

Mun, μ Kyeom,Ho, Lee Won,Park, Jin Woo,San Kim, Doo,Yeom, Geun Young,Kim, Dong Woo American Scientific Publishers 2017 Journal of nanoscience and nanotechnology Vol.17 No.11

<P>Nanoparticles in a solution can be modified by various methods including wet treatment, UV light treatment, and plasma treatment for the functionalization of the nanoparticles. Especially, for the plasma treatment of nanoparticles in a solution, hydrophilic treatment is generally carried out by forming -OH in the solution while the plasma treatment system is located at the outside of the nanoparticle solution. In this study, using a He/SF6 atmospheric plasma jet (APPJ) sources located outside and inserted in the IPA solution with carbon black nanoparticles, carbon black nanoparticles were modified to improve hydrophobic properties. By inserting the plasma jet tip in the solution, the carbon black nanoparticles were more easily modified compared the plasma jet located outside of the solution. After the He/SF6 plasma treatment of carbon black nanoparticles with the APPJ in the solution, the contact angle of the sprayed-coated carbon black was increased from similar to 30 to similar to 140 degrees while no significant change of contact angle was observed for the carbon black nanoparticles treated by the APPJ located outside of the solution. After the He/SF6 plasma treatment, fluorine percentage of similar to 7.97% in the carbon black was observed without noticeable thickness change of carbon black nanoparticles. It is believed that, the fluorine radicals dissolved in the solution form C-F (x) bonding on the carbon black surface and increase the hydrophobicity significantly. This technique can be applied in modifying the surface properties of various other particles in solution.</P>

A New Approach to Short-term Price Forecast Strategy with an Artificial Neural Network Approach

Mun-Kyeom Kim 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

In new deregulated electricity market, short-term price forecasting is key information for all market players. A better forecast of market-clearing price (MCP) helps market participants to strategically set up their bidding strategies for energy markets in the short-term. This paper presents a new prediction strategy to improve the need for more accurate short-term price forecasting tool at spot market using an artificial neural networks (ANNs). To build the forecasting ANN model, a threelayered feedforward neural network trained by the improved Levenberg-marquardt (LM) algorithm is used to forecast the locational marginal prices (LMPs). To accurately predict LMPs, actual power generation and load are considered as the input sets, and then the difference is used to predict price differences in the spot market. The proposed ANN model generalizes the relationship between the LMP in each area and the unconstrained MCP during the same period of time. The LMP calculation is iterated so that the capacity between the areas is maximized and the mechanism itself helps to relieve grid congestion. The addition of flow between the areas gives the LMPs a new equilibrium point, which is balanced when taking the transfer capacity into account, LMP forecasting is then possible. The proposed forecasting strategy is tested on the spot market of the Nord Pool. The validity, the efficiency, and effectiveness of the proposed approach are shown by comparing with time-series models

Plasma press for improved adhesion between flexible polymer substrate and inorganic material

Mun, Mu Kyeom,Kim, Doo San,Kim, Dong Woo,Yeom, Geun Young Butterworth-Heinemann Ltd. 2019 International journal of adhesion & adhesives Vol.89 No.-

<P><B>Abstract</B></P> <P>A novel adhesion process called “plasma press” has been investigated for achieving stronger bonding between two different materials. It was first developed to be applied in multilayer flexible printed circuit boards for next generation flexible mobile electronics. The plasma process is a hot pressing method employing plasma between the two materials in order to activate the material surfaces. Compared to the conventional hot-pressed sample, the plasma-pressed sample exhibited up to 130% higher adhesion strength. The stronger bond strength achieved in the plasma-pressed sample is attributed to the formation of active carboxyl functional groups and dangling bonds on the material surfaces by the presence of the plasma during the hot pressing process for bonding.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two different materials can be strongly bonded when they are glued together while the plasma between the two materials is on. </LI> <LI> Due to the unsaturated bonding that exists on the surfaces of the materials when the plasma between the materials is on, strong atomic bonding can be achieved. </LI> <LI> In addition, when the plasma is on, due to the active species between the two materials during the bonding process, stronger bonding between the two materials is possible. </LI> <LI> Lower surface contamination of the materials during the bonding process is also achievable, compared to during the bonding process conducted without plasma or after the plasma process. </LI> <LI> Lower temperature press bonding is possible during the hot press bonding, which makes it possible to use low temperature substrates as bonding materials. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Nanoparticles Synthesis and Modification using Solution Plasma Process

Mun, Mu Kyeom,Lee, Won Oh,Park, Jin Woo,Kim, Doo San,Yeom, Geun Young,Kim, Dong Woo The Korean Vacuum Society 2017 Applied Science and Convergence Technology Vol.26 No.6

Across the most industry, the demand for nanoparticles is increasing. Therefore, many studies have been carried out to synthesize nanoparticles using various methods. The aim of this paper is to introduce an industry-applicable as well as financially and environmentally effective solution plasma process. The solution plasma process involves fewer chemicals than the traditional kit, and can be used to replace many of the chemical agents employed in previous synthesis of nanoparticles into plasma. In this study, this process is compared to the wet-reaction process that has thus far been widely used in the most industry. Furthermore, the solution plasma process has been classified into four different types (in-solution, out of solution, direct type, and remote type), according to its plasma occurrence position and plasma types. Thus, the source of radicals, nanoparticle synthesis, and modification methods are explained for each design. Lastly, unlike nanoparticles with hydrophilic functional groups that are made inside the solution, a nanoparticle synthesis and modification method to create a hydrophobic functional group is also proposed.

Roughening of Polyimide Surface for Inkjet Printing by Plasma Etching Using the Polyimide Masked with Polystyrene Nanosphere Array

Mun, μ Kyeom,Park, Jin Woo,Ahn, Jin Ho,Kim, Ki Kang,Yeom, Geun Young American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.10

Self-selective fine metal line coating using surface energy differences

Mun, Mu Kyeom,Kim, Doo San,Yeom, Geun Young,Kim, Dong Woo Elsevier 2018 MICROELECTRONIC ENGINEERING Vol.187 No.-

<P><B>Abstract</B></P> <P>Self-selective coating is a new coating process that utilizes surface energy differences for metal ink coating. Hydrophobic and hydrophilic areas are defined on carbon black coated Polyimide (PI) substrate surface using atmospheric plasmas. At this state, when Ag ink is sprayed on PI, metal line is self-formed on hydrophilic surface due to its surface energy differences. As a result, an Ag ink line width of less than 6μm could be formed on the PI surface after removing the carbon black. Due to the formation of the Ag line on the hydrophilic PI surface, the adhesion force of the Ag ink formed on the PI surface was ~64% higher than that of the Ag ink formed on the hydrophobic PI surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Metal line in flexible device was made using new direct patterning method. </LI> <LI> Surface energy differences were used for direct patterning. </LI> <LI> Line width narrower than 6um was acquired by coating Ag ink on hydrophilic surface. </LI> <LI> Adhesion forces between the substrate were enhanced by 64% compared to that of hydrophobic substrate. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Two-Stage Model for Security Network-Constrained Market Auction in Pool-Based Electricity Market

Mun-Kyeom Kim 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.6

This paper presents a two-stage market auction model in a pool-based electricity market, which explicitly takes into account the system network security. The security network-constrained market auction model considers the use of corrective control to yield economically efficient actions in the post-contingency state, while ensuring a certain security level. Under this framework, the proposed model shows not only for quantifying the correlation between secure system operation and efficient market operation, but also for providing transparent information on the pricing system security for market participants. The two-stage market auction procedure is formulated using Benders decomposition (BD). In the first stage, the market participants bid in the market for maximizing their profit, and the independent system operator (ISO) clears the market based on social welfare maximization. System network constraints incorporating post-contingency control actions are described in the second stage of the market auction procedure. The market solutions, along with the BD, yield nodal spot prices (NSPs) and nodal congestion prices (NCPs) as byproducts of the proposed two-stage market auction model. Two benchmark systems are used to test and demonstrate the effectiveness of the proposed model.

A New Approach to Short-term Price Forecast Strategy with an Artificial Neural Network Approach: Application to the Nord Pool

Kim, Mun-Kyeom The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

In new deregulated electricity market, short-term price forecasting is key information for all market players. A better forecast of market-clearing price (MCP) helps market participants to strategically set up their bidding strategies for energy markets in the short-term. This paper presents a new prediction strategy to improve the need for more accurate short-term price forecasting tool at spot market using an artificial neural networks (ANNs). To build the forecasting ANN model, a three-layered feedforward neural network trained by the improved Levenberg-marquardt (LM) algorithm is used to forecast the locational marginal prices (LMPs). To accurately predict LMPs, actual power generation and load are considered as the input sets, and then the difference is used to predict price differences in the spot market. The proposed ANN model generalizes the relationship between the LMP in each area and the unconstrained MCP during the same period of time. The LMP calculation is iterated so that the capacity between the areas is maximized and the mechanism itself helps to relieve grid congestion. The addition of flow between the areas gives the LMPs a new equilibrium point, which is balanced when taking the transfer capacity into account, LMP forecasting is then possible. The proposed forecasting strategy is tested on the spot market of the Nord Pool. The validity, the efficiency, and effectiveness of the proposed approach are shown by comparing with time-series models

Nkjet System 적용을 위한 유연 필름의 대기압 플라즈마 표면 처리 연구

Mu Kyeom Mun,Geun Young Yeom 한국진공학회 2014 한국진공학회 학술발표회초록집 Vol.2014 No.2

Two-Stage Model for Security Network-Constrained Market Auction in Pool-Based Electricity Market

Kim, Mun-Kyeom The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.6

This paper presents a two-stage market auction model in a pool-based electricity market, which explicitly takes into account the system network security. The security network-constrained market auction model considers the use of corrective control to yield economically efficient actions in the post-contingency state, while ensuring a certain security level. Under this framework, the proposed model shows not only for quantifying the correlation between secure system operation and efficient market operation, but also for providing transparent information on the pricing system security for market participants. The two-stage market auction procedure is formulated using Benders decomposition (BD). In the first stage, the market participants bid in the market for maximizing their profit, and the independent system operator (ISO) clears the market based on social welfare maximization. System network constraints incorporating post-contingency control actions are described in the second stage of the market auction procedure. The market solutions, along with the BD, yield nodal spot prices (NSPs) and nodal congestion prices (NCPs) as byproducts of the proposed two-stage market auction model. Two benchmark systems are used to test and demonstrate the effectiveness of the proposed model.