• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1038-1041
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• 2003

In the paper, we investigated silicon surface microstructures formed by reactive ion etching in hollow cathode system. Wet anisotropic chemical etching technique use to form random pyramidal structure on <100> silicon wafers usually is not effective in texturing of low-cost multicrystalline silicon wafers because of random orientation nature, but High density hollow cathode plasma system illustrates high deposition rate, better film crystal structure, improved etching characteristics. The etched silicon surface is covered by columnar microstructures with diameters form 50 to 100nm and depth of about 500nm. We used $SF_{6}$ and $O_{2}$ gases in HCP dry etch process. This paper demonstrates very high plasma density of $2{\times}10^{12}$ $cm^{-3}$ at a discharge current of 20 mA. Silicon etch rate of 1.3 ${\mu}s/min$. was achieved with $SF_{6}/O_{2}$ plasma conditions of total gas pressure=50 mTorr, gas flow rate=40 sccm, and rf power=200 W. Our experimental results can be used in various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications. In this paper we directed our study to the silicon etching properties such as high etching rate, large area uniformity, low power with the high density plasma.

• 한국표면공학회지
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• 제51권6호
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• pp.344-353
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• 2018

Plasma electrolytic oxidation of Ti-25Ta-xHf alloy in electrolyte containing Ca and P for dental implants was investigated using various experimental techniques. Ti-25Ta-xHf (x=0 and 15 wt.%) alloys were manufactured in an arc-melting vacuum furnace. Micropores were formed in PEO films on Ti-25Ta-xHf alloys in 0.15 M calcium acetate monohydrate + 0.02 M calcium glycerophosphate at 240 V, 270 V and 300 V for 3 min, respectively. The microstructure of Ti-25Ta-xHf alloys changed from (${\alpha}^{\prime}+{\alpha}^{{\prime}{\prime}}$) phase to (${\alpha}^{{\prime}{\prime}}+{\beta}$) phase by addition of Hf. As the applied potential increased, the number of pore and the area ratio of occupied by micro-pore decreased, whereas the pore size increased. The anatase phase increase as the applied potential increased. Also, the crystallite size of anatase-$TiO_2$ can be controlled by applied voltage.

• 공업화학
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• 제30권6호
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• pp.719-725
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• 2019

본 실험에서는 활성탄소섬유에 산소플라즈마 처리를 실시하여 산소작용기 도입 함량에 따른 유독성 화학작용제의 모사 가스인 dimethyl methylphosphonate (DMMP) 감응특성에 대하여 고찰하였다. 산소플라즈마 처리 유량이 증가할수록 활성탄소섬유 표면에 산소가 6.90%에서 최대 36.6%까지 도입되어 DMMP 가스 감응특성에 영향을 미치는 -OH가 증가하였다. 그러나 유량이 증가할수록 산소플라즈마 처리 시 발생한 산소 활성종으로 인하여 활성탄소섬유 표면에 식각이 발생하여 비표면적은 감소하는 경향을 보였다. DMMP 가스센서의 저항변화율은 산소플라즈마 처리 유량이 증가함에 따라 4.2%에서 최대 25.1%까지 증가하였다. 이는 산소플라즈마 처리로 인하여 활성탄소섬유에 발달된 -OH와 DMMP 가스의 수소결합으로 인한 것이라 여겨진다. 따라서 산소플라즈마 처리는 상온에서 유독성화학작용제 가스를 감지하기 위한 중요한 표면처리 방법 중 하나라고 판단된다.

• 한국재료학회지
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• 제12권10호
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• pp.776-783
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• 2002

Austenitic stainless steel (STS304) has been carburized using glow discharge plasma and its microstructure, wear resistance and corrosion property have been investigated. A repeat boost-diffuse carburizing was used as an effective plasma carburizing method. The effective case depth of the plasma carburized specimens was increased with the carbon concentration at the surface area. The specimens prepared by 3 hours plasma carburizing under $600^{\circ}C$ did not have the standard hardness for the effective case depth, but the specimen prepared by 11 hours plasma carburizing at $500^{\circ}C$ had nearly the same hardness with the specimen plasma carburized for 3 hours at $800^{\circ}C$. The wear resistance increased with temperature but the corrosion properties of the specimens prepared over $600^{\circ}C$ decreased rapidly due to the grain boundary sensitization. However, the specimen plasma carburized for 11 hours at $500^{\circ}C$ had nearly the same wear resistance with the specimen plasma carburized for 3 hours at $800^{\circ}C$ without deterioration of corrosion property. This could be resulted from the fact that the microstructure of the specimen plasma carburized for 11 hours at $500^{\circ}C$ was composed of martensite and austenite, because a partial martensite transformation was occurred only in the specimen plasma carburized for 11 hours at 50$0^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.240-243
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• 2002

Carbon nitride films have been deposited on Si(100) substrate by a high voltage discharge plasma combined with laser ablation in a nitrogen atmosphere. The films were grown both with and without the Presence of an assisting focused Nd:YAG laser ablation. The laser ablation of the graphite target leads to vapor Plume plasma expending into the ambient nitrogen arc discharge area. X-ray photoelectron spectroscopy and Auger electron spectroscopy were used to identify the binding structure and the content of the nitrogen species in the deposited films. The surface morphology of the films was studied using a scanning electron microscopy Data of infrared spectroscopy and x-ray photoelectron spectroscopy indicate the existence of carbon-nitrogen bonds in the films. The x-ray diffraction measurements have also been taken to characterize the crystal properties of the obtain films.

• 대한화상학회지
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• 제22권2호
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• pp.25-29
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• 2019

Purpose: This study was performed to investigate the effect of plasma lactate clearance as predictive factor of major burn patients. Methods: A retrospective review was performed on 119 patients from January 2014 to December 2018, who were admitted as severe burn patients to ICU unit. Plasma lactate was measured upon admission to the hospital and 24hrs after admission. And, hospital day, ICU day, TBSA (Total Body Surface Area) and numbers of surgical intervention were collected after admission. Results: Higher lactate clearance showed negative statistical correlation with survival, hospital day, ICU day & number of surgical interventions. Conclusion: In this study, 24hr lactate clearance might be used as predictor of clinical prognosis following major burn injury.

• 한국진공학회지
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• 제19권1호
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• pp.28-35
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• 2010

플라즈마 디스플레이 패널에서 명실콘트라스트(bright room contrast ratio: BRCR)를 개선하는 방향으로 새로운 전극구조를 설계하였다. 새로운 개념의 전극을 이용하여 블랙매트릭스 패턴의 영역을 넓힐 수 있었으며 이를 통하여 패널면의 반사휘도를 낮출 수 있었다. 제작한 플라즈마 디스플레이 패널에 대하여 방전전압, 방전효율, 휘도 등을 평가하였으며 명실콘트라스트가 크게 개선됨을 확인하였다.

• 한국세라믹학회지
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• 제48권1호
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• pp.1-5
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• 2011

Silicon carbide (SiC) has recently drawn an enormous industrial interest because of its useful mechanical properties such as thermal resistance, abrasion resistance and thermal conductivity at high temperature. RF Thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) has been utilized for synthesis of high purity SiC powder from cheap inorganic solution (Tetraethyl Orthosilicate, TEOS). It is found that the powders by thermal plasma consist of SiC with free carbon and amorphous silica ($SiO_2$) and, by thermal treatment and HF treatment, the impurities are driven off resulting high purity SiC nano-powder. The synthesized SiC powder lies below 30 nm and its properties such microstructure, phase composition, specific surface area and free carbon content have been characterized by X-ay diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric (TG) and Brunauer-Emmett-Teller (BET).

• 한국세라믹학회지
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• 제49권6호
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• pp.523-527
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• 2012

Silicon carbide (SiC) has recently drawn an enormous amount of industrial interest due to its useful mechanical properties, such as its thermal resistance, abrasion resistance and thermal conductivity at high temperatures. In this study, RF thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) was utilized for the synthesis of high-purity SiC powder from an organic precursor (hexamethyldisilazane, vinyltrimethoxysilane). It was found that the SiC powders obtained by the RF thermal plasma treatment included free carbon and amorphous silica ($SiO_2$). The SiC powders were further purified by a thermal treatment and a HF treatment, resulting in high-purity SiC nano-powder. The particle diameter of the synthesized SiC powder was less than 30 nm. Detailed properties of the microstructure, phase composition, and free carbon content were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), a thermogravimetric (TG) analysis, according to the and Brunauer-Emmett-Teller (BET) specific surface area from N2 isotherms at 77 K.

• 한국식품영양학회지
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• 제30권2호
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• pp.290-296
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• 2017

In this study, using the surface dielectric barrier discharge (DBD) produced at atmospheric pressure to improve the physiological activities of quercetin was investigated. Quercetin (at 200 ppm) was treated using air DBD with an input power of 250 W. The tyrosinase inhibition effect and total phenolic content of quercetin increased from 38.96 to 91.58% and from 134.53 to 152.93 ppm, respectively, after 20 min of plasma treatment. The antioxidant activity of quercetin treated for 20 min in the lipid models was higher than that of quercetin treated for 0, 5, and 10 min. Furthermore, plasma-treated quercetin exhibited antimicrobial activity against Listeria monocytogenes, Salmonella Typhimurium, and Staphylococcus aureus, whereas activity was not shown in the control. Structural modifications of the quercetin molecule induced by plasma might be responsible for the improvements in its physiological activity. These results indicate that DBD plasma could be used to enhance the physiological activity of quercetin for various applications in food.