• Nuclear Engineering and Technology
• /
• 제55권11호
• /
• pp.4032-4038
• /
• 2023

Cu, which exhibits excellent corrosion resistance in underground environments, has been investigated as a canister material for use in the deep geological disposal of spent nuclear fuels. In this study, the technical viability of atmospheric plasma spraying for producing Cu-coated canisters was investigated. A high-purity Cu film (millimeter scale) was deposited onto a stainless-steel substrate using a plasma gun with a shroud structure. Potentiodynamic polarization studies revealed that the Cu film exhibited a sufficiently low corrosion rate in the groundwater electrolyte. In addition, no pitting corrosion was observed on the Cu film surface after accelerated corrosion studies. A prototype cylindrical Cu film was fabricated on a 1/20 scale on a stainless-steel tube to demonstrate the scalability of atmospheric plasma spraying in producing Cu-coated canisters.

• 한국대기환경학회지
• /
• 제16권4호
• /
• pp.373-380
• /
• 2000

A new type of photocatalyst plasma air purification filter for decomposition of some VOCs has been developed. The photocatalyst plasma air purification filter employs the pulsed discharge plasma as an energy source of TiO2. photocatalyst instead of UV light. In closed room(2m3) test removal efficiency of some VOCs was 80∼100% in 15∼24 hours. In the initial step of phptocatalyst plasma reaction. Acetone and Nitromethane etc were detected. But they were completely oxidized to CO2 and H2O.

• Transactions on Electrical and Electronic Materials
• /
• 제10권3호
• /
• pp.71-74
• /
• 2009

Electroplated Cu is a cost efficient metallization method in microelectronic packaging applications. Typically in 3-D chip staking technology, utilizing through silicon via (TSV), electroplated Cu metallization is inevitable for the throughput as well as reducing the cost of ownership (COO).To achieve a comparable film quality to sputtering or CVD, a pre-cleaning process as well as plating process is crucial. In this research, atmospheric plasma is employed to reduce the usage of chemicals, such as trichloroethylene (TCE) and sodium hydroxide (NaHO), by substituting the chemical assisted organic cleaning process with plasma surface treatment for Cu electroplating. By employing atmospheric plasma treatment, marginally acceptable electroplating and cleaning results are achieved without the use of hazardous chemicals. The experimental results show that the substitution of the chemical process with plasma treatment is plausible from an environmentally friendly aspect. In addition, plasma treatment on immersion Sn/Cu was also performed to find out the solderability of plasma treated Sn/Cu for practical industrial applications.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.254.1-254.1
• /
• 2014

Atmospheric plasma's electron temperature is less than thermal plasma, so it is useful at bio experiment. We have investigated the optical emission spectroscopy (OES) lines by spectrometer during Atmospheric plasma bombardment onto the PBS surface by using an Ar gas flow. Also we have measured the OH radical density inside the solution induced by the Atmospheric plasma bombardment. OH radical species are appeared at 308 nm and 309 nm. Densities of OH radical species has been found to be significantly decreased versus depth of the solution from 2 mm to 6 mm. OH radical density inside the PBS is measured to be about $1.87{\times}1016cm-3$ downstream at 2 mm from the surface under optimized Ar gas flow of 200 sccm in Atmospheric plasma. Also we have investigated cell viability of lung cancer and normal cell after Atmospheric plasma treatment for fixed exposure time in 60 seconds, but different depths. We used SEM, we observed change of cell morphorogy, did experiment about FDA & PI Staining method. It is found that there is selectivity between the lung cancer and lung normal cell, in which cancer cell definitely has higher cell death ratio more than normal cell. We have investigated change of bond structure in FT-IR spectroscopy, the following peaks were observed: and intense O-H peak at 3422 cm-1 and at 2925 cm-1 corresponds to C-H stretch vibrations of methylene group.

• Korean Chemical Engineering Research
• /
• 제57권3호
• /
• pp.432-437
• /
• 2019

유연전극 기반의 대기압 부유전극 유전체 장벽 방전 (floating electrode-dielectric barrier discharge, FE-DBD) 시스템을 개발하여 플라즈마 특성을 분석하였다. 유연한 파워전극(powered electrode)을 구성하는 유연유전체로 polytetrafluoroethylene (PTFE), polydiemethylsiloxane (PDMS), polyethylene terephthalate (PET)를 사용하여 플라즈마를 발생하였을 때 플라즈마의 광학적 세기와 전자온도는 파워전극에 인가하는 전압이 증가할수록 증가하였고, 전압이 일정할 때는 PTFE < PDMS < PET 순으로 증가하였다. 이는 유전체의 종류와 전압에 따른 축전용량의 변화로 설명할 수 있었고, 유연전극 기반의 대기압 FE-DBD 플라즈마의 특성은 유연한 파워전극을 구성하는 유전체와 파워전극에 인가되는 전압을 변화함으로써 조절될 수 있음을 의미한다. 유연전극 대기압 FE-DBD 시스템은 피부 곡면을 따라 플라즈마가 발생될 수 있으므로 플라즈마 메디신(plasma medicine)에 유용할 것으로 기대한다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.195.1-195.1
• /
• 2016

Currently, as Plasma application is expanded to the industrial and medical industrial, low temperature plasma applications became important. Especially in medical and biology, many researchers have studied about generated radical species in atmospheric pressure low temperature plasma directly adapted to human body. Therefore, so measurement their plasma parameter is very important work and is widely studied all around world. One of the plasma parameters is electron density and it is closely relative to radical production through the plasma source. some kinds of method to measuring the electron density are Thomson scattering spectroscopy and Millimeter-wave transmission measurement. But most methods have very expensive cost and complex configuration to composed of experiment system. We selected Michelson interferometer system which is very cheap and simple to setting up, so we tried to measuring electron density by laser interferometer with laser beam chopping module for measurement of temporal phase difference in plasma jet. To measuring electron density at atmospheric pressure Ar plasma jet, we obtained the temporal phase shift signal of interferometer. Phase difference of interferometer can occur because of change by refractive index of electron density in plasma jet. The electron density was able to estimate with this phase difference values by using physical formula about refractive index change of external electromagnetic wave in plasma. Our guiding laser used Helium-Neon laser of the centered wavelength of 632 nm. We installed chopper module which can make a 4kHz pulse laser signal at the laser front side. In this experiment, we obtained more exact synchronized phase difference between with and without plasma jet than reported data at last year. Especially, we found the phase difference between time range of discharge current. Electron density is changed from Townsend discharge's electron bombardment, so we observed the phase difference phenomenon and calculated the temporal electron density by using phase shift. In our result, we suggest that the electron density have approximately range between 1014~ 1015 cm-3 in atmospheric pressure Ar plasma jet.

• Applied Science and Convergence Technology
• /
• 제24권1호
• /
• pp.16-21
• /
• 2015

The characteristics of an atmospheric pressure plasma jet (APPJ) in He discharge are measured with electrical and optical diagnostics methods. The discharge phenomenon in one cycle of the APPJ was diagnosed using intensified charge coupled device (ICCD) imaging. The gate mode images show that the propagation of plasma bullets happens only when the applied voltage on the inner conductor is positive. Moreover, the Schlieren image of the plasma jet shows that the laminar flow is changed into a turbulent flow when the plasma jet is turned on, especially when the gas flow rate increases.

• 대한기계학회논문집A
• /
• 제32권4호
• /
• pp.354-361
• /
• 2008

Cold rolled steel sheet for automotive was treated by Ar/$O_2$ atmospheric pressure plasma to improve the adhesive bonding strength. Through the contact angle test and calculation of surface free energy for cold rolled steel sheet, the changes of surface properties were investigated before and after plasma treatment. The contact angle was decreased and surface free energy was increased after plasma treatment. And the change of surface roughness and morphology were observed by AFM(Atomic Force Microscope). The surface roughness of steel sheet was slightly changed. Based on Taguchi method, single lap shear test was performed to investigate the effect of experimental parameter such as plasma power, treatment time and flow rate of $O_2$ gas. Results shows that the bonding strength of steel sheet treated in Ar/$O_2$ atmospheric pressure plasma was improved about 20% compared with untreated sheet.

• International Journal of Oral Biology
• /
• 제43권2호
• /
• pp.83-91
• /
• 2018

Nonthermal atmospheric plasma has been studied for its many biomedical effects, such as tooth bleaching, wound healing, and coagulation. In this study, the effects of dentinal tubules occlusion were investigated using fluoride-carboxymethyl cellulose (F-CMC) gel, nano-sized hydroxyapatite (n-HA), and nonthermal atmospheric plasma. Human dentin specimens were divided to 5 groups (group C, HA, HAF, HAP, and HAFP). Group HA was treated with n-HA, group HAF was treated with n-HA after a F-CMC gel application, group HAP was treated with n-HA after a plasma treatment and group HAFP was treated with n-HA after a plasma and F-CMC gel treatment. The occlusion of dentinal tubules was investigated using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), which shows Ca/P ratio. In the EDS results, a higher Ca/P ratio was shown in the groups including n-HA than in the control group. The specimens of group HAP and HAFP had a higher Ca/P ratio in retentivity. In the SEM results, there was not a significant difference in the amount of times applied. Therefore, this study suggests F-CMC gel and n-HA treatment using nonthermal atmospheric plasma will be a new treatment method for decreasing hypersensitivity.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2003년도 춘계학술발표회 초록집
• /
• pp.54-54
• /
• 2003

MgO layer는 POP 패빌 내 유전증을 이온의 스퍼터링으로부터 보호하여 주며, 또한 높은 이차 전자 밤출 계수의 특성을 가지고 있어 구동 및 유지 전압을 낮춰 주는 역할을 한다. 그러나. MgO layer는 $H_20,{\;}CO_2,{\;}N_2,{\;}0_2$ 그리고 $H_2$와 같은 불순물 들을 쉽게 를착하는 단점이 있어, PDP의 특성 및 수명 단축에 영향을 줄 수 있다. 따라서, 본 연구에서는 atmospheric pressure plasma cleaning 과 low pressure i inductively coupled plasma (ICP) cleaning 처리에 의하여, 보호층으로 사용이 되는 MgO layer의 outgassing 특성을 조사하고자 한다. plasma cleaning에 의한 MgO layer 표면의 roughness와 불순물의 변화를 알아보기 위 하여 atomic force microscopy(AFM)과 x-ray p photoelectron spectroscopy(XPS)를 이용하여 측정 하였다. 또한, outgassing의 특성을 분석하기 위하여 MgO layer를 $400^{\circ}C$ 까지 온도를 가하여 온도에 따른 outgassing의 특성을 quadrupole mass spectrometer(QMS)를 이용하여 알아보았다. atmospheric pressure plasma cleaning 에서는 $He/O_2/Ar/N_2$의 gas를 사용하였으며, low pressure ICP cleaning 에 서는 Ar의 gas를 사용하였다. atmospheric pressure plasma cleaning는 low pressure ICP C cleaning과 비교해 더 낮은 outgassing을 관잘 할 수 있었으나. MgO 표면의 roughness는 low pressure ICP cleaning 후 더 낮은 것을 알 수 있었다. 또한 $He/O_2/Ar/N_2$의 gas를 사용 한 atmospheric pressure plasma cleaning 과 $Ar/O_2$의 gas를 사용한 ICP cleaning에서 이 차전자방출계수(SEEC)가 약 1.5~2.5배 증가된 것을 알 수 있었다.