• 공업화학
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• 제29권1호
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• pp.103-111
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• 2018

본 연구에서는 온도가 큰 폭으로 변화하는 배기가스에 대응하기 위하여 플라즈마 촉매 공정을 이용하여 넓은 온도범위($150{\sim}500^{\circ}C$)에서 질소산화물($NO_x$)의 전환효율을 향상시키고자 하였다. 촉매 자체의 활성이 높은 고온에서는 $NO_x$저감이 효과적으로 일어나므로 고온 영역에서는 플라즈마 발생을 중지한 채 운전하고, 저온영역에서는 촉매상에 플라즈마를 발생시켜 $NO_x$ 전환효율을 증가시켰다. 촉매의 종류, 반응온도, 환원제(n-헵테인)의 농도 및 에너지 밀도의 변화가 $NO_x$ 전환효율에 미치는 영향을 조사하였다. 다양한 촉매를 비교분석한 결과, 고온에서 촉매에 의한 $NO_x$ 전환효율은 $Ag-Zn/{\gamma}-Al_2O_3$ 촉매의 경우가 90% 이상으로 가장 우수하였다. 저온 영역에서는 탄화수소 선택적 환원 공정에 의해 $NO_x$가 거의 제거되지 않았으나, 플라즈마를 촉매상에서 발생시킬 경우 약 90%의 높은 $NO_x$ 전환효율을 나타내었다. 배기가스의 온도변화에 대응하여 플라즈마를 촉매상에 생성시켜 운전할 경우 $150{\sim}500^{\circ}C$에서 $NO_x$ 전환효율을 높게 유지할 수 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.180-180
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• 2010

The design and implementation of high rate deposition process and anti-scratch property of silicon oxide film by PECVD with UHF power were investigated according to the effect of UHF input power with HF bias. New regime of high rate deposition of SiOx films by hybrid plasma process was investigated. The dissociation of OMCTS (C8H24Si4O4) precursor was controlled by plasma processes. SiOx films were deposited on polyethylene terephthalate (PET) and polycarbonate substrate by plasma enhanced chemical vapor deposition (PECVD) using OMCTS with oxygen carrier gas. As the input energy increased, the deposition rate of SiOx film increased. The plasma diagnostics were performed by optical emission spectrometry. The deposition rate was characterized by alpha-step. The mechanical properties of the coatings were examined by nano-indenter and pencil hardness, respectively. The deposition rate of the SiOx films could be controlled by the appropriate intensity of excited neutrals, ionized atoms and UHF input power with HF bias at room temperature, as well as the dissociation of OMCTS.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.179-179
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• 2016

A radio-frequency (RF) Inductively Coupled Plasma (ICP) torch system was used for boron-nitride nano-tube (BNNT) synthesis. Because of electrodeless plasma generation, no electrode pollution and effective heating transfer during nano-material synthesis can be realized. For stable plasma generation, argon and nitrogen gases were injected with 60 kW grid power in the difference pressure from 200 Torr to 630 Torr. Varying hydrogen gas flow rate from 0 to 20 slpm, the electrical and optical plasma properties were investigated. Through the spectroscopic analysis of atomic argon line, hydrogen line and nitrogen molecular band, we investigated the plasma electron excitation temperature, gas temperature and electron density. Based on the plasma characterization, we performed the synthesis of BNNT by inserting 0.5~1 um hexagonal-boron nitride (h-BN) powder into the plasma. We analysis the structure characterization of BNNT by SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy), also grasp the ingredient of BNNT by EELS (Electron Energy Loss Spectroscopy) and Raman spectroscopy. We treated bundles of BNNT with the atmospheric pressure plasma, so that we grow the surface morphology in the water attachment of BNNT. We reduce the advancing contact angle to purity bundles of BNNT.

• 한국분말재료학회지
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• 제16권6호
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• pp.403-409
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• 2009

Plasma spray forming is recently explored as a near-net-shape fabrication route for ultra-high temperature metals and ceramics. In this study, monolithic tungsten has been produced using an atmospheric plasma spray forming and subsequent high temperature sintering. The spray-formed tungsten preform from different processing parameters has been evaluated in terms of metallurgical aspects, such as density, oxygen content and hardness. A well-defined lamellae structure was formed in the as-sprayed deposit by spreading of completely molten droplets, with incorporating small amounts of unmelted/partially-melted particles. Plasma sprayed tungsten deposit had 84-87% theoretical density and 0.2-0.3 wt.% oxygen content. Subsequent sintering at 2500$^{\circ}C$ promoted the formation of equiaxed grain structure and the production of dense preform up to 98% theoretical density.

• Applied Science and Convergence Technology
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• 제24권5호
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• pp.142-150
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• 2015

A failure analysis of tungsten filaments used in quadrupole mass spectrometer for plasma process monitoring was carried by using SEM and EDS. Failed at high temperature, filaments showed two kinds of failure modes. The one is that diameter of filament became thinner gradually and finally snapped. The other is that filament abruptly snapped almost at a right angle. The EDS analysis showed Fe and C, including W and Fe, on the surface of failed filament. when failed filaments were treated with plasma in mixture of Ar and $CF_4$, the amount of Fe and C decreased. The failure analysis of filament showed that the cause of filament failure is thermal evaporation and grain growth of tungsten at high temperature.

• 한국전기전자재료학회논문지
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• 제18권8호
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• pp.696-701
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• 2005

This paper was investigated the changes of surface properties of high-temperature-vulcanized (HTV) semiconductive silicone rubber due to oxygen plasma discharge. The modifications produced on the silicone rubber surface by oxygen plasma were accessed using Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), contact angle and Surface Roughness Tester. The results of the chemical analysis Showed that C-H bonds were broken due to plasma discharge and Silica-like bonds (SiOx, x=$3\~4$) increased. It is thought that the above changes lead to the increase of surface energy of high-temperature-vulcanized (HTV) semiconductive silicone rubber also, Surface roughness was increased with cleavage of side-chains and oxidation process, it confirmed change as the SEM. The micromorphology of surface and hydrophobicity due to plasma discharge based on our results were discussed.

• 한국표면공학회지
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• 제31권6호
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• pp.325-333
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• 1998

A duplex surface treatment process of simultaneous aluminizing-chromizing process followed by plasma nitriding was performed on AISI HI3 steel and STS 403 steel. The properties of these duplex-treated steels were investigated and were compared with those of steels treated by single process of either simultaneous aluminizing-chromizing or plasma nilriding, in terms of microstructure, microhardness and high temperature wear resistance. Sim~dtaneous alumizing-chromizing process was done using a 2-step coating cycle and plasma nitriding process was done at $530^{\circ}C$ for 1.5 hour. AISI HI3 steel and STS 403 steel showed a FeA1 compound layer of approximately 350$\mu\textrm{m}$ thickness on the surface after simultaneous diffusion coating and nitrided layer of approximately 70-80$\mu\textrm{m}$ formed after the subsequent plasma nitriding process. The microhardness was improved much more by the duplex surface heatment than only by plasma nitriding. In addition the duplex treated specimens showed an improved high temperature wear resistance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집
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• pp.25-28
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• 2005

This paper was investigated the changes of surface properties of high-temperature-vulcanized(HTV) semiconductive silicone rubber due to oxygen plasma discharge. The modifications produced on the silicone surface by oxygen plasma were accessed using x-ray photoelectron spectroscopy(XPS), contact angle and Scanning Electron Microscope(SEM). The results of the chemical analysis showed that C-H bonds were broken due to plasma discharge and Silica-like bonds (SiOx. x=3~4) increased. It is thought that the above changes lead to the increase of surface energy of high-temperature-vulcanized(HTV) semiconductive silicone rubber. The micromorphology of surface and hydrophobicity due to plasma discharge based on our results were discussed.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2003년도 춘계학술대회 발표 논문집
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• pp.12-17
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• 2003

본 연구에서는 MICP Etching system 을 이용한 Via contact 및 Deep contact hole etch process 특성을 연구하였다. Langmuir probe 를 이용한 MICP source 의 Plasma density & electron temperature 측정하였고 탄소와 플로우르를 포함하는 혼합 Plasma 를 형성하여 RF frequency, wall temperature, chamber gap, gas chemistry 등의 변화에 따른 식각 특성을 조사하였다. Plasma density 는 1000w 에서 $10^{11}$/$cm^3$ 이상의 high density plasma와 uniform plasma 형성을 확인하였고 $CH_{2}F_{2}$와 CO의 적절한 혼합비를 이용하여 Oxide to PR 선택비가 10 이상인 고선택비 조건을 확보하였다. 고선택비 형성에 따라 Polymer 형성이 많이 되었고 이를 개선하기 위하여 반응 챔버의 온도 조절을 통하여 Polymer 증착 방지에 효과적인 것을 확인하였다. MICP source를 이용하여 탄소와 플로우르의 혼합 가스와 식각 챔버의 온도 조절에 의한 선택비 증가를 확보하여 High Aspect Ratio Contact Hole Etch 가능성을 확보하였다.

• Fisheries and Aquatic Sciences
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• 제26권2호
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• pp.117-132
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• 2023

Chum salmon (Oncorhynchus keta) is a species of anadromous salmonid inhabiting coastal rivers in the North Pacific and the Arctic in the Bering and is the most widely distributed among Pacific salmon species. It is an important fish species in Korea as the salmon releasing project is being actively carried out. This study was conducted to investigate changes in the physiological activity of O. keta according to water temperature. Three experiments were conducted according to the water temperature and period, and the plasma concentrations of cortisol and glucose were analyzed from the blood samples of the experimental groups. Experiment I is a short-term water temperature experiment, in which water temperature stimulation was given for 4 hours at water temperatures of 12℃, 16℃ (control), 20℃, and 24℃, and a recovery period was given for 4 hours. Experiment II is an experiment in which water temperature stimulation was given for 24 hours, 48 hours, and 72 hours at a high temperature of 24℃, and a recovery period was given for 12 hours, respectively. Experiment III is a long-term water temperature experiment, in which the water temperature was 12℃, 16℃ (control), 20℃, and 24℃ for 8 weeks. As a result of the experiment, in Experiment I, there was no significant difference in the survival rate between the experimental groups, but the concentration of cortisol and glucose in the plasma according to the set water temperature showed a significant difference. In Experiment II, there was no significant trend according to the maintenance time of the high-temperature state, but as the temperature increased, the plasma cortisol and glucose levels significantly increased compared to the control group. In Experiment III, all of the experimental group C (24℃) died in the 1st week, and there was no significant difference in the plasma glucose at the 1st and 8th weeks among the remaining experimental groups.