• 한국연소학회:학술대회논문집
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• 한국연소학회 1998년도 제17회 KOSCI SYMPOSIUM 논문집
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• pp.31-36
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• 1998

An experimental study has been performed to characterize fundamental aspects of VOCs removal using non-thermal palsma technique. The removed VOCs in the present study are toluene ($C_6H_5CH_3$), ethene ($C_2H_4$), propene ($C_3H_6$) which are typical air pollutants generated from industry and automobile engines. The non-thermal plasma used in the present experiments has been produced in a wire-cylinder reactor with pulsed corona or a packed-bed reactor filled with ceramic bead. These differently generated non-thermal plasma have been visualized with an intensified CCD. The images of non-thermal plasma have been used for optimal design of a corona reactor used in the present study. The experimental results show that the removal efficiencies of VOCs with non-thermal plasma are dependant on the reactivity of VOCs with OH, O, and $O_3$. The results also show that the removal efficiencies of VOCs decrease significantly when VOCs are treated with NO that is also oxidized in the presence of OH, O, and $O_3$.

• Current Optics and Photonics
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• 제1권5호
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• pp.500-504
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• 2017

In this paper, we developed a temperature measurement system based on an infrared temperature imaging module for thermal safety verification of a plasma skin treatment device (PSTD). We tested a pilot product of the low-temperature PSTD using the system, and the temperature increase of each plasma torch was well-monitored in real-time. Additionally, through the approximation of the temperature increase of the plasma torches, a certain limitation of the plasma treatment time on skin was established with the International Electrotechnical Commission (IEC) guideline. We determined an appropriate plasma treatment time ($T_{Safe}$ < 24 minutes) using the configured temperature measurement system. We believe that the temperature measurement system has a potential to be employed for testing thermal safety and suitability of various medical devices and industrial instruments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.209-211
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• 2002

A simple-structured thermal plasma generator for waste gas treatment has been studied. The thermal plasma technology applied to waste treatment has undoubtedly gained high importance owing to its outstanding properties such as flexibility, compact reactor, and clean treatment. Moreover, the thermal plasma generated by ac power has some additional advantages such as simple electrode system and easy maintenance. A prototype 200kW class plasma generator with specifications of 10-30m/sec gas velocity and 3000-5000K temperature on the center just outside of the nozzle has been designed and tested. Case studies on heat transfer, heat flow, velocity distribution, and temperature distribution using a commercial simulation package show lots of flexibility in design. The experimental results from theprototype generator show that the ac thermal plasma is easily controlled by working gas flow once it is ignited. A stabilization condition is discussed with the data from monitoring arc voltage drops with respect to gas flow rate during the test.

• 한국산업보건학회지
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• 제28권1호
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• pp.61-79
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• 2018

Objectives: The objective of this study was to examine the effect of non-thermal dielectric barrier discharge(DBD) plasma on decontamination of Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) as common pathogens. Methods: This experiment was carried out in a chamber($0.64m^3$)designed by the authors. The plasma was continuously generated by a non-thermal DBD plasma generator(Model TB-300, Shinyoung Air tech, Korea). Suspensions of S. aureus and E. coli of 0.5 McFarland standard($1.5{\times}10^8CFU/mL$) were prepared using a Densi-Check photometer(bio $M{\acute{e}}rieux$, France). The suspensions were diluted1:1000 in sterile PBS solutions(approximately$10^{4-5}CFU/mL$) and inoculated on tryptic soy agar(TSA) in Petri dishes. The Petri dishes(80mm internal diameter)were exposed to the non -thermal DBD plasma in the chamber. Results: The results showed that 95% of S. aureus colonies were killed after a six-hour exposure to the DBD plasma. In the case of E. coli, it took two hours to kill 100% of the colonies. The gram-negative E. coli had a greater reduction than the gram-positive S. aureus. This difference may be due to the structure of their cell membranes. The thickness of gram-positive bacteria is greater than that of gram-negative bacteria. The S. aureus is more resistant to DBD plasma exposures than is E. coli. It should be noted that average concentrations of ozone, a byproduct of the DBD plasma generator, were monitored throughout the experiment and the results were well below the criteria, 50 ppb, recommended by the Korean Ministry of the Environment. Thus, non-thermal DBD plasma is deemed safe for use in hospital and public facilities. Conclusions: There was evidence that non-thermal DBD plasma can effectively kill S. aureus and E. coli. The results indicate that DBD plasma technology can greatly contribute to the control of infections in hospitals and other public and private facilities.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.15-19
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• 2006

The meat consumption produces a lot of bone waste everyday. Dumping bone waste without treatment results into environmental hazards. Conventional treatment by pyrolysis is slow, inefficient and produces hazardous by-products. In the work, an investigation of bone waste incinerated using thermal plasma technology is presented. A high temperature arc plasma torch operated at 33 kW was employed for the experiments. Bone waste was incinerated to remove the infectious organic matter and to vitrify the inorganic matter using plasma torch. Bone waste was reduced its 2/3 weight after the treatment. The process was highly efficient, economical, convenient, and fuel free. This method could be used as an alternative method for disposal of bone waste, small infectious animals, hazardous hospital waste, etc.

• Journal of Welding and Joining
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• 제7권2호
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• pp.25-34
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• 1989

The purpose of this work is to coat ZrO$_{2}$ - 8Y$_{2}$O$_{3}$ ceramic on the Al cast alloy(AC-8A) by using the plasma spray method. Two types of coatings which were composed of two and three layer coating were examined. Each coating powder was analyzed for shape and size distribution and X-ray diffraction pattern. For the coated layers, microstructural analysis and performance estimation which was composed of static thermal test, thermal cyclic test and thermal shock test were conducted.

• The Journal of Advanced Prosthodontics
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• 제10권6호
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• pp.408-414
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• 2018

PURPOSE. This study aimed to assess the effect of non-thermal plasma on the shear bond strength of resin cements to polyetherketoneketone (PEKK) in comparison to other surface treatment methods. MATERIALS AND METHODS. Eighty PEKK discs were subjected to different surface treatments: (1) Untreated (UT); (2) Non-thermal plasma (NTP); (3) Sandblasting with $50{\mu}m$ $Al_2O_3$ particles (SB); and (4) Sandblasting + Non-thermal plasma (SB+NTP). After each surface treatment, the contact angle was measured. Surface conditioning with Visio.Link was applied in all groups after pre-treatment. RelyX Unicem resin cement was bonded onto the PEKK specimens. After fabrication of the specimens, half of each group (n=10) was initially tested, while the other half was subjected to thermocycling ($5^{\circ}C$ to $55^{\circ}C$ at 10,000 cycles). Shear bond strength (SBS) testing was performed using a universal testing machine, and failure modes were assessed using stereomicroscopy. The SBS results were analyzed statistically using one-way ANOVA followed by Tukey's post hoc test. Independent t-test was used to examine the effect of thermocycling (P<.05). RESULTS. The highest SBS values with or without thermocycling were observed with PEKK specimens that were treated with SB+NTP followed by the SB group. The lowest SBS results were observed in the UT groups. CONCLUSION. The shear bond strength between PEKK and resin cements was improved using non-thermal plasma treatment in combination with sandblasting.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1349-1352
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• 2005

This paper is to investigate a defect for thermal barrier coating layers by acoustic emission method in 4-point bending test. The two-layer thermal barrier coating is composed of $150\mu{m}\;CoNiCrAlY\;bond\;coating\;by\;vacuum\;plasma\;spray(VPS)\;process\;and\;250\mu{m}\;ZrO_2-8wt%Y_2O_3$ ceramic coating layer by air plasma spray(APS) process on Inconel-718. The specimen prepared by cyclic thermal test(500, 1000, 2000cycle) at $1050^{\circ}C$ The AE monitoring system is composed of PICO type sensor, a wide band pre-amplifier(40dB), PC and AE DSP(16/32 PAC) board. The AE event, amplitude, Cumulative energy and count of coating specimens is evaluated according to cyclic thermal test.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.450-454
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• 2018

In recent years, thermal insulation coating technology for automotive engine parts has received significant attention as a means of improving the thermal efficiency of automotive engines. One of the characteristics of thermal insulation coatings is their low thermal conductivity, and, materials such as YSZ (Yttria-stabilized zirconia), which have low thermal conductivity, are used for this purpose. This research presents a study of the changes in the microstructure and thermal conductivity of $8YSZ/SiO_2$ multi compositional thermal insulation coating for different compositions, and particle size distributions of suspension, when it is subjected to suspension plasma spraying. To obtain a porous coating structure, the mixing ratio of 8YSZ and $SiO_2$ particles and the particle sizes of the $SiO_2$ were changed. The microstructure, phase formation behavior, porosity and thermal conductivity of the coatings were analyzed. The porosities were found to be 1.2-32.1%, and the thermal conductivities of the coatings were 0.797-0.369 W/mK. The results of the study showed that the microstructures of the coatings were strongly influenced by the particle size distributions, and that the thermal conductivities of the coatings were greatly impacted by the microstructures of the coatings.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권3호
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• pp.29-35
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• 2007

본 연구에서는 산소플라즈마로 티타늄을 산화하고 급속열처리하여 티타니아 광촉매 박막을 제조하고 휴믹산 제거실험을 수행하였다. 플라즈마 화학기상증착장치에서의 산소플라즈마는 티타늄 표면을 산화시킴으로써 광촉매 피막을 생성하게 된다. 증착조건에서 RF power는 최대 500 W 이하에서 100 W, 150 W, 300 W, 처리시간은 5분, 10분에서 조절되었다. 박막의 특성은 XPS와 XRD로 측정하였다. 실험으로서 우리는 박막이 높은 성능을 나타내는 최적을 조건을 찾았다. 또한 제조된 박막의 경우 기존 Thermal spray Titania film에 비해 2배정도 우수하였고 분말만큼 광촉매 성능을 갖는다.