• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.890-896
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• 2009

Li(Ni, Co, Mn)$O_2$ has been known as one of the most promising cathode materials for lithium secondary batteries. However, it has some problems to overcome for commercialization such as inferior rate capability and unstable thermal stability. In order to address these problems, surface modification of cathode materials by coating has been investigated. In the coating techniques, selection of coating material is a key factor of obtaining enhanced properties of cathode materials. In this work, we introduced solid electrolyte (Li-La-Ti-O) as a coating material on the surface of $Li[Ni_{0.3}Co_{0.4}Mn_{0.3}]O_2$ cathode. Specially, we focused on a rate performance of Li-La-Ti-O coated $Li[Ni_{0.3}Co_{0.4}Mn_{0.3}]O_2$ cathode. Both bare and Li-La-Ti-O 2 wt.% coated sample showed similar discharge capacity at 0.5C rate. However, as the increase of charge-discharge rate to 3C, the coated samples displayed better discharge capacity and cyclic performance than those of bare sample.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.607-612
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• 2021

Silicon (Si) is one of the promising active materials to replace the widely used graphite because of its low electrochemical potential and high theoretical capacity. However, Si anodes still face in problems with the huge volume expansion and continuous decomposition of the electrolyte during repeated charge and discharge processes. To address these issues, a cross-linkable waterborne polyurethane (CWPU) based on a bio-oil, castor oil, was prepared and reacted with Tris(2,3-epoxypropyl) isocyanurate (TGIC) linkers, resulting in the formation of a mechanically robust 3D network structure. Si anodes fabricated with the CWPU-TGIC exhibited stable cycling performances and excellent discharge capacities. The results revealed that the CWPU-TGIC binder efficiently accommodates the large volume change for Si anode during charge and discharge cycles. Overall, the eco-friendly binder shows great promise in improving the electrochemical performances of Si anodes.

• Korean Journal of Materials Research
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• v.33 no.7
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• pp.315-322
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• 2023

In the present work, we address the new route for the green synthesis of manganese dioxide (MnO₂) by an innovative method named the solution plasma process (SPP). The reaction mechanism of both colloidal and nanostructured MnO₂ was investigated. Firstly, colloidal MnO₂ was synthesized by plasma discharging in KMnO₄ aqueous solution without any additives such as reducing agents, acids, or base chemicals. As a function of the discharge time, the purple color solution of MnO₄^- (oxidation state +7) was changed to the brown color of MnO₂ (oxidation state +4) and then light yellow of Mn²⁺ (oxidation state +2). Based on the UV-vis analysis we found the optimal discharging time for the synthesis of stable colloidal MnO₂ and also reaction mechanism was verified by optical emission spectroscopy (OES) analysis. Secondly, MnO₂ nanoparticles were synthesized by SPP with a small amount of reducing sugar. The precipitation of brown color was observed after 8 min of plasma discharge and then completely separated into colorless solution and precipitation. It was confirmed layered type of nanoporous birnessite-MnO₂ by X-ray powder diffraction (XRD), fourier-transform infrared spectroscopy (FT-IR), and electron microscopes. The most important merits of this approach are environmentally friendly process within a short time compared to the conventional method. Moreover, the morphology and the microstructure could be controllable by discharge conditions for the appropriate potential applications, such as secondary batteries, supercapacitors, adsorbents, and catalysts.

• Journal of the Korean Society of Safety
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• v.39 no.1
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• pp.9-15
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• 2024

Hydrogen-based electricity and transportation systems are widely recognized as sustainable power sources. However, the low ignition energy of hydrogen, only 1/10th that of conventional fossil fuels, poses a safety concern involving the risk of ignition due to electrostatic discharge from facility workers. Therefore, anti-static systems are imperative for hydrogen-based electricity facilities. To address this, we propose a reliable conductive rubber mat (CRM) to ensure the safety of these facilities. Unlike conventional anti-static floors that utilize conductive paint (CP), the CRM features a uniform distribution of conductive components in chemically and mechanically stable rubber. As a result, the CRM is unyielding to polar solvents (such as ethanol and hydrosulfuric acid) and non-polar solvents (like mineral oil) without increasing its resistance. Moreover, the CRM can withstand mechanical stress. Consequently, the human-body voltage of workers on the CRM would be sufficiently low enough to protect them from hydrogen explosions, thereby enhancing overall safety.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.9-11
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• 2003

Image sticking, the phenomenon that the previously displayed pattern still remains after the image is changed into different image, is one of the most serious problem in realizing high picture quality. There are various methods decreasing the image sticking phenomenon. In this paper, we have tried to decrease boundary image sticking by reducing the discharge concentration phenomenon in the boundary of pattern using the new driving method that is applied to bias in the address electrode.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.586-590
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• 2009

Recently, an AC Plasma Display Panels(PDP) with the metal sustain electrodes have been reported in order to reduce the manufacturing cost of the AC PDP. However, the luminance and efficacy of the AC PDP with metal electrodes are worse than those of the AC PDP with ITO electrodes. In this paper, various ${\prod}$type metal electrodes are suggested, in order to improve the electro-optical characteristics of the AC PDP with metal electrodes. Among the suggested electrode types, luminance of Hump electrode structure is higher by $40\;cd/m^2$ and discharge current of Asymmetry electrode structure is lower by 5% than those of Pi electrode structure, respectively. Moreover, $T_1$ of Hump electrode structure is reduced to 10% as compared with Pi electrode structure in address period for ADS driving scheme. In all aspects, the characteristics of Hump and Asymmetry electrode structure show best performance.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.965-969
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• 2008

MgO thin film is widely used in PDP panel for protecting the dielectric layer and making firing voltage low. In this paper, the MgO thin film and discharge characteristics was analyzed as hydrogen flow rate increasing. Using hydrogen in deposition chamber makes add delay time of PDP module longer or shorter. It is the reason why thin film surface layer thickness on the MgO surface changes.

• Journal of Power Electronics
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• v.13 no.5
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• pp.779-786
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• 2013

A highly efficient sustaining driver is proposed for plasma display panels (PDPs). When the PDP is charged and discharged, the proposed sustaining driver employs an address voltage source used in an addressing period. A voltage source is used for fully charging the panel to the sustaining voltage, and an initial inductor current helps the panel discharge to 0 V. The resonance between the panel and an inductor is made by shifting the voltage and current bias level when charging and discharging the panel. As a result, the proposed circuit can reduce power consumption, switching loss, heat dissipation, and production cost. Experimental results of a 42-inch PDP are provided to verify the operation and features of the proposed circuit.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.325-328
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• 2003

We have proposed a new reset discharge method for AC PDP, which is composed of fast Ramp biased Multiple Short Pulses (RMSP). By using this method, we achieved stable reset discharges with reduced reset time. At the same time, it resulted in lower background luminance as well as stable and higher address margin using the tail effect.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.239-244
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• 2008

In order to improve cost and efficacy of AC PDP with metal discharge electrodes, a new II-type metal electrodes are suggested. The suggested asymmetrical II-type metal electrode is improved in the luminance, power and efficacy than the conventional metal electrode by 7.5%, 6%, and 14%, respectively. The efficacy of the suggested asymmetrical II-type metal electrode is almost the same with the conventional ITO electrode. Moreover, the address time of the II-type metal electrode is shorter than the conventional ITO electrode.