• Journal of Powder Materials
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• v.24 no.1
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• pp.46-52
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• 2017

Fecralloy coating layer with large surface area is suitable for use as a filter media for efficient removal of hot gaseous pollutants exhausted from combustion processes. For uniform preparation of a Fecralloy coating layer with large surface area and strong adhesion to substrate, electrospray coating and thermal treatment processes are experimentally optimized in this study. A nano-colloidal solution with 0.05 wt% Fecralloy nanoparticles is successfully prepared. Optimized electrospraying conditions are experimentally discovered to prepare a uniform coating layer of Fecralloy nano-colloidal solution on a substrate. Drying the electrospray coated Fecralloy nano-colloidal solution layer at $120^{\circ}C$ and subsequent heating at $600^{\circ}C$ are the best post-treatment for enhancing the adhesion force and surface roughness of the Fecralloy coating layer on a substrate. An electrospray coating system, consisting of several multi-groove nozzles, is also experimentally confirmed as a reasonable device for uniform coating of Fecralloy nano-colloid on a large area substrate.

• Polymer(Korea)
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• v.33 no.6
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• pp.620-624
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• 2009

Biomedical metal implants have been used clinically for replacement, restoration, or improvement of injury bodies based on high mechanical properties, but it has some risks such as the inflammatory, late thrombosis, or restenosis due to the low biocompatibility and toxicity. In various techniques of surface treatment developed to preserve these drawbacks, this study examined the electrospray coating technology with biodegradable poly (lactic-co-glycoic acid) (PLGA) on metal surface. Based on fundamental examination of electrospraying and solution parameters, the surface morphology of coated film was closely related to the boiling point of solvent, in-flight distance, and droplet size. The thickness of polymer film was linearly proportional to the emerged volume. This result exhibits that the polymeric droplets were continuously deposited on the polymer film. Therefore, the electrospray coating technology might be applied into the fabrication of single/multi-layered polymer film in nano-/micro-thickness and the control of the topology for biomedical metal implants including stents.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.2
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• pp.118-124
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• 2016

In this study, experiments are conducted to improve spray coating uniformity by using second and third electrodes based on the electrospray atomization mechanism. The uniformity of fabricated thin films can be improved by adjusting the design of the second electrode. The implementation of the second electrode with an elongated hole and a bending angle of $90^{\circ}$ results in highly uniform films. In addition, induced area to substrate is increased by lowering the applied voltage using the third electrode with a round rod shape. A linear correlation between applied voltage and induced area is confirmed. Thin film thickness and surface roughness are measured after the fabrication of thin films through the electrospray process. It is confirmed that a thin film is formed having an average thickness of 273.44 nm, a thickness uniformity of less than 10%, and a surface roughness of 3 nm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2223-2228
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• 2009

Dye sensitized solar cells(DSCs) have been very economical and easy method to convert solar energy to electricity. DSC can reach low costs in future outdoor power applications. However, to commercialize the DSC, there are still many shortages to overcome such a low efficiency in a large size DSC. In this study, DSCs were fabricated by an electrospray coating method for the $TiO_2$ thin film. They were compared with DSCs prepared by conventional coating methods. We conducted an experiment to obtain the optimized parameters of voltage, flow rate, incident angle and distance in the electrospray method. After we fabricated $TiO_2$ film using that way, we investigated the characteristics of DSC through I-V Curve, SEM and EIS. This novel method shows stable performance with an energy conversion efficiency of 3.44 % under 1 sun illumination (AM 1, $P_{in}$ of $100\;mW/cm^2$).

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.125-134
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• 2013

Various antimicrobial technologies have been developed to inactivate bioaerosols in indoor environments. In this study, air filter media were treated with a natural antibacterial agent of Sophora flavescens in order to inactivate the bacteria collected on the air filter. Three treatment methods were applied to manufacture the test antibacterial air filter media: electrospray, nebulization and dip-coating methods. In case of electrospray and nebulization processes, the size distribution of aerosolized natural antibacterial agent was measured using a scanning mobility particle sizer. Staphylococcus epidermidis bacteria were aerosolized to test inactivation of the filter media treated with a natural antibacterial agent. The pressure drop and the antibacterial efficiency of the filter media increased with increasing the mass loading of natural antibacterial agent in each treatment method. The antibacterial efficiency per loaded antibacterial agent mass by the electrospray method was the highest and the filter treated by the dip-coating method was the lowest among three treatment methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.381-382
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• 2008

$TiO_2$ colloidal solution was electrosprayed for preparing a conductive thin film with high quality. Electrospray is a technique of liquid dispersion electrically and a good method of manufacturing nanoparticle, nanofiber, porous membrane, film preparation and coating. Water and ethanol were used as solvents and their mixing ratio was varied for studying the influence of solvent volatile on nanoparticle dispersion. Various nozzles to control the thru-put of solutions.were examined. Integrated analytical method and scanning electron microscope were used to analyze integrity and microscopic images.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1423_1424
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• 2009

Dye sensitized solar cells(DSC) have been very economical and easy method to convert solar energy to electricity. DSC can reach low costs in future outdoor power applications. However, to commercialize the DSC, there are still many shortages to overcome such as a low efficiency in a large size DSC. In this study, DSCs were fabricated by an electrospray coating method for the $TiO_2$ thin film. They were compared with DSCs prepared by conventional coating methods. We conducted an experiment to obtain the optimized parameters of voltage, flow rate, incident angle and distance in the electrospray method. After we manufactured $TiO_2$ film using that way, we could analyze the characteristics of DSC through SEM, UV curve, EIS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.407-408
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• 2010

• Korean Journal of Materials Research
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• v.24 no.3
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• pp.145-151
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• 2014

Solution-based Sb-doped $SnO_2$ (ATO) transparent conductive oxides using a low-temperature process were fabricated by an electrospray technique followed by spin coating. We demonstrated their structural, chemical, morphological, electrical, and optical properties by means of X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, Hall effect measurement system, and UV-Vis spectrophotometry. In order to investigate optimum electrical and optical properties at low-temperature annealing, we systemically coated two layer, four layer, and six layers of ATO sol-solution using spin-coating on the electrosprayed ATO thin films. The resistivity and optical transmittance of the ATO thin films decreased as the thickness of ATO sol-layer increased. Then, the ATO thin films with two sol-layers exhibited superb figure of merit compared to the other samples. The performance improvement in a low temperature process ($300^{\circ}C$) can be explained by the effect of enhanced carrier concentration due to the improved densification of the ATO thin films causing the optimum sol-layer coating. Therefore, the solution-based ATO thin films prepared at $300^{\circ}C$C exhibited the superb electrical (${\sim}7.25{\times}10^{-3}{\Omega}{\cdot}cm$) and optical transmittance (~83.1 %) performances.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.367-367
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• 2014

Transparent conductive oxides (TCOs) 박막은 가시광선영역에서의 높은 투과율과 낮은 저항 특성을 동시에 갖고 있어 최근 smart windows, solar cells, liquid crystal displays (LCD), organic light emitting devices (OLED)등과 같은 최첨단 기기에 필수적인 구성요소로 활발히 사용되고 있다. 따라서, 현재까지 FTO ($SnO_2:F$), ITO ($In_2O_3:Sn$), ATO ($SnO_2:Sb$)등과 같은 다양한 TCO들이 많은 연구자들에 의해 연구되고 있다. 그 중 ITO는 우수한 전기적(${\sim}10^{-4}{\Omega}cm$) 및 광학적(~85%) 특성 때문에 현재 상업적으로 활발히 응용되고 있는 대표적인 물질이다. 하지만 ITO의 주된 구성요소인 indium은 제한적인 매장량과 과도한 소비량 때문에 원가가 비싸다는 문제점이 있다. 반면에, ATO는 우수한 전기적(${\sim}10^{-3}{\Omega}cm$) 및 광학적(~80%) 특성뿐만 아니라 구성물질들의 매장량이 풍부하여 ATO의 원가가 저렴하다는 장점을 가지고 있어 현재 ITO을 대체 할 수 물질로 관심 받고 있다 [1]. 지금까지 우수한 특성을 갖는 ATO박막을 합성하는 방법으로 sol-gel spin coating, sputtering, spray pyrolysis, chemical vapor deposition (CVD)등이 알려져 있다. 이 중에서도, sol-gel spin coating과 spray pyrolysis은 solution기반의 합성법으로 분류되며 합성과정이 간단하고 비용이 저렴하다는 장점이 있고 현재까지 많은 연구가 보고되었다. 그러나, 진공기반이 아닌 우수한 특성을 갖는 solution기반의 ATO박막을 합성하기 위해서는 새로운 합성법의 개발이 학문적으로나 산업적으로도 매우 중요한 이슈이다. 따라서, 본 연구에서는 electrospray을 활용하여 solution기반의 ATO박막을 처음으로 합성하였다. 게다가 ATO박막에 열처리온도에 따른 구조, 화학, 전기, 광학적 특성을 확인하기 위하여 X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), Hall Effect Measurement System, UV spectrophotometer를 사용하였다. 이러한 실험 결과들을 바탕으로 electrospray을 통해 합성된 solution기반의 ATO박막에 자세한 특성을 본 학회에서 다루도록 하겠다.