• Corrosion Science and Technology
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• v.18 no.5
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• pp.155-167
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• 2019

In this study, two novel Schiff base compounds including (3-(4-Chlorophenyl isoxazole-5-yl) methanol and (3-(2,4 dichlorophenol isoxazole-5-yl) methanol as corrosion inhibitors for mild steel in 1 M hydrochloric acid solution were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and density functional theory (DFT) computations. The results showed that the corrosion inhibition efficiency (IE) is remarkably enhanced with the growing concentration of the Schiff base inhibitors. The results from Tafel polarization and EIS methods showed that IE decreases with gradual increments of temperature. This process can be attributed to the displacement of the adsorption/desorption balance and hence to the diminution of the level of a surface coating. Also, the adsorption of two inhibitors over mild steel followed the Langmuir adsorption isotherm. Too, the results of the scanning electron microscope (SEM) images showed that the Schiff base inhibitors form an excellent protective film over mild steel and verified the results by electrochemical techniques. Additionally, the results from the experimental and those from DFT computations are in excellent accordance.

• Current Photovoltaic Research
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• v.11 no.1
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• pp.13-17
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• 2023

Functional transparent electrode was achieved by metal oxide-metal-Metal oxide (OMO) structure. Tailoring of metal oxide and metal layers, optically transparent and electrically excellent OMO films were investigated. Silver (Ag) is adopted for the metal layer and Ag oxide (AgO) is reactively formed by flowing O₂ gas during the sputtering process. This spontaneous AgO formation from Ag simultaneously provides the good electrical interface with high transparency. Due to the feature of transparent electrode of OMO, it endows the shielding effect (SE) function of electromagnetic interference. Optically transparent and electrically conductive OMO electrode shows the high transmittance (83.7%) and low sheet resistance (6.5 Ω/☐) with SE of 29.54 dB.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.35-36
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• 2023

Safety management of steel frame members is a very important part to maintain safety and function. However, precise inspection is not possible for steel frame members due to finishing materials and insulation materials, leading to poor inspection. For steel members, an insulating spray coating method is used for high thermal conductivity. The insulation spray method is not only uneconomical, but also has the disadvantage of spoiling the aesthetics. In addition, VOCs are released from paints used in spraying, so a solution is needed. In this study, heating paint was used to improve the disadvantages of the insulation spray coating method and the high thermal conductivity of steel frame members. In addition to this, in order to reduce VOCs generated from the paint, active clay was added to produce a functional exothermic paint, and then the experiment was conducted. As the amount of activated clay increased, the film thickness increased, and the VOCs emission and thermal conductivity decreased.

• Corrosion Science and Technology
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• v.23 no.1
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• pp.20-32
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• 2024

Metal corrosion in acidic environments is a major issue in various industrial applications. This study evaluates the 4-piperonylideneaminoantipyrine (PPDAA) corrosion inhibition efficiency for mild steel in a hydrochloric acid (HCl) solution. The weight loss method was used to determine the corrosion inhibition efficiency at different concentrations and immersion time periods. Results revealed that the highest inhibition efficiency (94.3%) was achieved at 5 mM concentration after 5 hours of immersion time. To inspect the surface morphology of the inhibitor film on the mild steel surface, scanning electron microscopy (SEM) was used before and after immersion in 1.0 M HCl. Density functional theory (DFT) calculations were performed to investigate the molecular structure and electronic properties of the inhibitor molecule to understand the corrosion inhibition mechanism. Theoretical results showed that the inhibitor molecule can adsorb onto the mild steel surface through its nitrogen and oxygen atoms, forming a protective layer that prevents HCl corrosive attack. These findings highlight the potential of PPDAA as an effective corrosion inhibitor for mild steel in HCl solution. Moreover, combining experimental and theoretical approaches provides insights into the mechanism of corrosion inhibition, which is essential for developing effective strategies to prevent metal corrosion in acidic environments.

• Journal of the Korean Electrochemical Society
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• v.23 no.3
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• pp.57-65
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• 2020

It is crucial to investigate the thermal degradation of lithium-ion batteries (LIBs) to understand the possible malfunction at high temperature. Herein, we investigated the effects of surface film formation on the thermal degradation of lithium cobalt oxide (LiCoO₂, LCO) cathode that is one of representative cathode materials. Cycling test at 60℃ exhibited poorer cycleability compared with the cycling at 25℃. Cathodes after the initial 5 cycles at 60℃ (60-LCO) exhibited higher impedance compared to the cathode after initial 5 cycles at 25℃ (25-LCO), resulting in the lower rate capability upon subsequent cycling at 25℃, although the capacity values were similar at the lowest C-rate of 0.1C. In order to understand degradation of the LCO cathode at the high temperature, we analyzed the cathodes surface using X-ray photoelectron spectroscopy (XPS). Among various peaks, intensity of lithium hydroxide (LiOH) increased substantially after the operation at 60℃, and the C-C signal that represents the conductive agent was distinctly lower on 60-LCO compared to 25-LCO. These results pointed to an excessive formation of cathode-electrolyte interphase including LiOH at 60℃, leading to the increase in the resistance and the resultant degradation in the electrochemical performances.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.2
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• pp.71-76
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• 2019

Recently, the demand of labels for product management is increasing, as the automation system becomes more common. the development of functional labels which can be used in various environments has been rapidly proceeded. In the case of a printed circuit board, barcode labels with thermal and chemical stability are generally used due to a high temperature process around $300^{\circ}C$ and chemical cleaning in the manufacturing process. However, the yellowing phenomenon of labels that can lower the resolution of printed barcode image still needs to be prevented. In this study, we prepared a composite coating layer using a silica inorganic binder and a titanium dioxide white pigment, and developed a functional labels with thermal and chemical stability. The silica inorganic binder prepared by sol-gel process was confirmed to show excellent adhesion and abrasion resistance with the polyimide film. The white coating layer could be formed on the polyimide film with mixing the silica inorganic binder and titanium dioxide white pigment. The prepared coating layer showed excellent whiteness and glossiness above $400^{\circ}C$. The excellent chemical stability of the coating layer was also confirmed by the chemical treatment with acidic (pH 1.6) and basic (pH 13.6) cleaners.

• Journal of Distribution Science
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• v.12 no.4
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• pp.73-83
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• 2014

Purpose - This study aims to classify and extend the consumer value of movie theaters into various values such as functional value, emotional value, social value, epistemic value, and conditional value based on the theory of consumption value by Sheth, Newman and Gross (1991). It also aims to verify the path structure of consumption value→customer satisfaction→behavior intention of movie theaters to confirm its generalization. Research design, data, and methodology - This study was conducted by collecting data on Kimpo university students from various areas in Incheon, Northern Seoul, Ilsan, Kyonggi Province, and Kimpo City. The survey was conducted by distributing 280 survey papers from Oct. 5 to 15, 2013 and collecting 238 of them. The final analysis used 208 questionnaires, after excluding 30 invalid responses. The statistical analysis of this study used the SPSS 19.0 statistics package. Results - The results of the survey are as follows: First, consumption values of movie theaters are classified into the following five groups: functional value, emotional value, social value, epistemic value, and conditional value. This study verified that consumption values play a role as a previous variable of customer satisfaction. Second, functional value, emotional value, and epistemic value have positive effects on customer satisfaction. On the other hand, social value and conditional value do not affect customer satisfaction. Finally, customer satisfaction has a positive impact on behavior intention. Theater users have an intention to re-use or recommend the movie theater they used when they are satisfied with a movie theater's physical environment and services. Conclusions - This study can provide academic and practical implications as follows based on the results mentioned above. First, academic implications can be found in that consumption values of movie theater users are classified into five values based on the theory of consumption value by Sheth et al. (1991). In the previous study, the service quality of a movie theater was studied based on the service quality of service encounters and a physical environment→customer satisfaction→behavior intention path structure. However, this study was verified by a consumption value→customer satisfaction→behavior intention path structure to classify consumption value, but not service quality or perceived value of quality, to confirm this generalization. Second, practical implications can be found in that the relative impact of consumption value of movie theaters on consumer satisfaction showed that functional value was followed by epistemic value and emotional value. In the previous study on movie theaters, previous variables of customer satisfaction were separated only by functional service quality including service encounters and physical environment; in some other studies, quality of service encounter had a direct effect on customer satisfaction. Accordingly, a marketing manager of a movie theater should develop various differentiated services by reflecting not only functional value such as service encounters and physical environment but also epistemic value and emotional value.

• Polymer(Korea)
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• v.33 no.1
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• pp.79-83
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• 2009

Thin electric insulation layers were coated on aluminum plates and aluminum condenser cases by plasma polymerization of HMDSO+$O_2$. Electric resistances of the films were higher than 1.0 M$\Omega$ if they are thicker than 0.5 ${\mu}m$ independently of the type of films but their surface morphologies and adhesion strengths were dependent on the process conditions. Deposition rate and adhesion strength of the films were dependent on $O_2$/HMDSO flow ratio and discharge power. The best result was obtained at $O_2$/HMDSO flow ratio of 4 and discharge power of 60 W. Adhesion strength could also be highly improved if aluminum was pre-treated in boiling water for 30 min through the formation of Al-O-Si bonding between the film and the aluminum surface. The coated films showed excellent chemical and thermal resistances.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.84.2-84.2
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• 2010

PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active components in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT, which are printed with functional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manufacturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem: it is difficult to apply toa continuous process as a R2R printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, anelectrostatic atomizer sprays micro-drops from the solution injected into the capillary, with electrostatic force generated by electric potential of about tens of kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and Active layer which consist of the P3HT:PCBM. The result of experiment, organic solar cell using ESD thin film coated method is occurred efficiency of about 1.4%. Also, the case of only used to ESD method in the active layer coating is occurred efficiency of about 1.86% as the applying a spin coating in the PEDOT:PSS layer. We can expect that ESD method is possible for continuous process to manufacture in the organic solar cell or OLED device.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.281.1-281.1
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• 2016

Transition metal dichalcogenides (TMDCs) are promising layered structure materials for next-generation nano electronic devices. Many investigation on the FET device using TMDCs channel material have been performed with some integrated approach. To use TMDCs for channel material of top-gate thin film transistor(TFT), the study on high-k dielectrics on TMDCs is necessary. However, uniform growth of atomic-layer-deposited high-k dielectric film on TMDCs is difficult, owing to the lack of dangling bonds and functional groups on TMDC's basal plane. We demonstrate the effect of remote oxygen plasma pretreatment of large area synthesized few-layer MoSe2 on the growth behavior of Al2O3, which were formed by atomic layer deposition (ALD) using tri-methylaluminum (TMA) metal precursors with water oxidant. We investigated uniformity of Al2O3 by Atomic force microscopy (AFM) and Scanning electron microscopy (SEM). Raman features of MoSe2 with remote plasma pretreatment time were obtained to confirm physical plasma damage. In addition, X-ray photoelectron spectroscopy (XPS) was measured to investigate the reaction between MoSe2 and oxygen atom after the remote O2 plasma pretreatment. Finally, we have uniform Al2O3 thin film on the MoSe2 by remote O2 plasma pretreatment before ALD. This study can provide interfacial engineering process to decrease the leakage current and to improve mobility of top-gate TFT much higher.