• Journal of Advanced Marine Engineering and Technology
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• 제35권2호
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• pp.252-257
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• 2011

본 연구에서는 초경량성 마그네슘 재료를 엔진 블록, 실린더 헤드커버 등과 같은 박용기관에 적용하기 위한 환경 친화적 표면처리의 개발에 대하여 고찰하였다. 또한 이온플레이팅법에 의해 마그네슘 박막을 제작하고, 그 제작조건에 따라 변화하는 막의 결정배향성과 몰포로지가 경도특성에 미치는 영향을 해명하고자 하였다. 마그네슘 박막의 경도측정 결과, 아르곤 가스압의 증가에 따라 그 경도값이 상승하였 는데, 그 원인은 결정립계에 의한 강화와 성분 외 가스입자의 흡장효과에 의한 것으로 사료된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.234.2-234.2
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• 2014

Organic light emitting diode (OLED) is considered as the next generation flat panel displays due to its advantages of low power consumption, fast response time, broad viewing angle and flexibility. For the flexible application, it is essential to develop thin film encapsulation (TFE) to protect oxidation of organic materials from oxidative species such as oxygen and water vapor [1]. In many TFE research, the inorganic film by atomic layer deposition (ALD) process demonstrated a good barrier property. However, extremely low throughput of ALD process is considered as a major weakness for industrial application. Recently, there has been developed a high throughput ALD, called 'spatial ALD' [2]. In spatial ALD, the precursors and reactant gases are supplied continuously in same chamber, but they are separated physically using a purge gas streams to prevent mixing of the precursors and reactant gases. In this study, the $Al_2O_3$ thin film was deposited by spatial ALD process. We characterized various process variables in the spatial ALD such as temperature, scanning speed, and chemical compositions. Water vapor transmission rate (WVTR) was determined by calcium resistance test and less than $10-^3g/m^2{\cdot}day$ was achieved. The samples were analyzed by x-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.324-324
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• 2008

Piezoelectric ceramics is an active element that makes stator to vibrate to generate rotational force in ultrasonic motors. In drive of ultrasonic motors, many factors that affect to the resonance characteristics of piezoelectric ceramics exist. For example, those factors are bonding condition with elastic body, the magnitude of electric field, the normal force for frictional drive and the emission of heat due to vibration and friction and so on. Therefore, it is important to research the inclination of property variation of piezoelectric ceramics in circumstance that has complex elements. In this paper, we focused and analyzed the resonance characteristics of ultrasonic motor due to the magnitude of the driving voltage and normal force.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1919-1924
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• 2012

Poly(anthranilic acid) was synthesized by rapid mixing method using 5-sulphosalicylic acid as a dopant. The synthesized polymer was characterized by various techniques like FT-IR, UV-Visible, and X-ray diffraction $etc.$, The FT-IR studies reveal that the 5-sulphosalicylic acid is well doped within the polymer. The morphological property was characterized by field emission scanning electron microscopic technique. The electrochemical properties of the polymer were studied by cyclic voltammetric method. The synthesized polymer was used to modify glassy carbon electrode (GCE) and the modified electrode was found to exhibit electrocatalytic activity for the oxidation of uric acid (UA).

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.55.2-55.2
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• 2009

A polymer electrolyte membrane (PEM) fuel cell has been getting large interest as a typical issue in useful applications. The PEMFC is composed of a membrane, catalyst and the bipolar plate. SnOx:F films on SUS316 stainless steel were prepared as a function of substrate with using electron cyclotron resonance-metal organic chemical vapor deposition (ECR-MOCVD) in order to achieve the corrosion-resistant and low contact resistance bipolar plates for PEM fuel cells. The SnOx:F films coated on SUS316 substrate at surface plasma treatment for excellent stability, before/after heat treatment for good crystalline structure and microwave power for were characterized by X-ray diffraction (XRD), auger electron microscopy (AES) and field emission-scanning electron microscopy (FE-SEM). The SnOx:F film coated on SUS316 substrate with various process parameters were able to observe optimum interfacial contact resistance (ICR) and corrosion resistance. It can be concluded that fluorine-doping content plays an important function in electrical property and characteristic of corrosion-protective film.

• 폴리머
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• 제38권6호
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• pp.744-751
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• 2014

Electrospinning was used to load curcumin (a natural compound that has antiinflammatory properties) into zein nanofibers. An emulsifier, Tween 80, was combined with curcumin in the zein nanofibers. The morphology of the curcumin-loaded zein nanofibers (CLZNFs) was observed using field emission scanning electron microscopy. Investigation of curcumin released from the zein nanofibers into phosphate buffer saline at pH 7 indicated that the Tween 80 had increased the amount of curcumin released from the CLZNFs. The antibacterial activity of the CLZNFs against Staphylococcus aureus (S. aureus) was determined by measuring the optical density of bacterial solutions containing CLZNFs. The zein nanofibers fabricated with 10 wt% surfactant and 1.6 wt% curcumin showed high (i.e., 83%) efficiency in inhibiting the growth of S. aureus in the solution incubated for 21 h. These results suggest that the electrospun CLZNFs show potential application as antibacterial nonwoven mats.

• 대한치과기공학회지
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• 제35권4호
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• pp.343-352
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• 2013

Purpose: The purpose of this study was to investigate to effect of the ZrN coated on corrosion resistance and physical property of dental Co-Cr alloys using various instruments. Methods: The specimens were used, respectively, for experiment, Arc Ion plating was carried out for dental casting alloys using ZrN coated materials with nitrogen gas. ZrN coated surface of each specimen was observed with field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), vickers hardness tester, and electrochemical tester. Results: The current density of ZrN coated specimen was smaller than that of non-coated specimen in 0.9% NaCl solution. Pit nucleated at scratch of specimen. The pitting corrosion resistant |$E_{max}-E_{rep}$| increased in order of ZrN coated (110 mV), and non-coated wire (100 mV). Conclusion: The corrosion potential of the ZrN coated specimen was comparatively high. the surface of ZrN coated specimen was more smooth than that of other kinds of non-coated specimen. ZrN coated surface showed higher hardness than that of non-coated surface.

• 한국재료학회지
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• 제22권10호
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• pp.526-530
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• 2012

Silica-based ceramic-matrix composites have shown promise as advanced materials for many applications such as chemical catalysts, ceramics, pharmaceuticals, and electronics. $SiO_2$-CuO-$CeO_2$ multi-component powders and their thin film, using an oxalic acid template as a chelating agent, have larger surface areas and more uniform pore size distribution than those of inorganic acid catalysts. $SiO_2$-CuO-$CeO_2$ composite powders were synthesized using tetraethylorthosilicate, copper (II) nitrate hemi (pentahydrate), and cerium (III) nitrate hexahydrate with oxalic acid as template or pore-forming agent. The process of thermal evolution, the phase composition, and the surface morphology of these powders were monitored by thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffractometry (XRD), field-emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectrometry (EDXS). The mesoporous property of the powders was observed by Brunner-Emmett-Teller surface (BET) analysis. The improved surface area of this powder template with oxalic acid was $371.4m^2/g$. This multi-component thin film on stainless-steel was prepared by sol-gel dip coating with no cracks.

• 방사선산업학회지
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• 제8권1호
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• pp.17-22
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• 2014

In this study, we prepared CdTe/CdS solar cells using a thermal vacuum evaporation method. In particular, $CdCl_2$ treatment was attempted using this same method at $400^{\circ}C$ for 30 min. The prepared CdTe/CdS solar cells were investigated using Fouier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FE-SEM), and a solar simulator system including light absorption properties, morphological properties, and power conversion efficiency (PCE). In addition, we investigated the gamma-irradiation treatment at dose rates of 0 Gy, 500 Gy, 1 kGy, 10 kGy, and 30 kGy. The characteristics of gamma-irradiation treatment were studied based on the same method described above. In particular, it showed increased values as 0.826% higher than the non-irradiation of 0.448% from PCE analysis.

• 폴리머
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• 제32권5호
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• pp.497-500
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• 2008

폴리스틸렌발포체(스티로폼)를 비롯한 소수성 폴리머의 재활용과 친수성 표면개질의 한 방편으로 산소플라즈마 고정화와 그래프팅법을 이용하여 친수성인 아크릴산과 아크릴아미드단량체를 스티로폼 표면에 도입하였다. 플라즈마 처리에 의한 표면개질의 증거는 ESCA스펙트럼의 O/C와 N/C ratio의 증가, 전계방사현미경의 사진으로부터 박막생성 및 접촉각의 현저한 감소 현상의 관찰로부터 확인하였다. 접촉각은 $84^{\circ}$에서 $18{\sim}19^{\circ}$로 대폭 감소하였으며, 이는 아크릴산보다 아크릴아미드가 결정적 요인이 됨을 알 수 있었다.