• Transactions of the Korean hydrogen and new energy society
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• v.34 no.1
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• pp.8-16
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• 2023

In this work, we report basic performance test results of a lab-scale three phase alternative current (AC) arc plasma torch system for plasma gas reforming applications. The suggested system primarily consists of three graphite electrodes inclined at 12.5° to the central axis, a 𝞥 150 mm cylindrical gas path and a three phase-60 Hz AC power supply. At air flow rate of 50 Lpm and arc currents of 100-175 A, test results revealed that plasma resistances were decreasing from 1.08 Ω to 0.53 Ω with the increase of plasma power from 9.3 kW to 13.8 kW, causing the decrease of power factor and increase of the line voltages. However, the injected air can be heated quickly up to the temperatures of >1,200℃ when injecting AC arc plasma powers of >10 kW.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.248-254
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• 2002

The most controversial topics in plasma sprayed ceramic coating system are recently mechanical properties such as bond strength, cohesive strength, toughness and so on. Determination of bond strength of coatings is one of the most important problems. In the industry, the bond strength of coating system has been estimated by Pull-off test(ASTM standard C633-79). But, without a fixed jig and specimen, it is impossible to obtain the bond strength. Therefore, it is necessary to study the critical fracture load on interface of the coating by indentation test. Because the critical fracture load plays an important role in evaluating the bond strength for plasma sprayed ceramic coating system. So, we have estimated critical fracture load in plasma sprayed ceramic coating system, and it was shown that inverse relationship between the cross-section hardness of coating and the critical fracture load(Pc). In case of the high load(1kgf, 2kgf) in $Al_{2}O_{3}+13%TiO_{2}$, it was found that the critical point(Pco), which the coating was broken on.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.373-380
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• 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 of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.93-99
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• 2008

To improve the performance of plasma-DeNOx catalyst, a research on active system was performed experimentally. Two hydrocarbons, propane and diesel, were used as a reductant in this study. First, using propane, basic performances of plasma-DeNOx catalyst such as the effects of plasma and C/N ratio were measured at the various engine operating conditions. NOx conversion of catalyst was improved as plasma power or C/N ratio was increased. Next, diesel was injected in the exhaust gas flow as a reductant. The first test using diesel as a reductant is spray visualization in a high temperature flow and spray images were utilized for analysis of posterior test results. To evaluate the effect of an injection direction, it was compared with 6 installation methods of diesel injector due to THC concentrations at the inlet of plasma. From the results, injector was installed toward downstream direction below the pipe. Then, basic performances of plasma-DeNOx catalyst with various injection quantities were measured. As an injection quantity was increased, $NO_2$ conversion of plasma reactor was increased but NOx conversion of catalyst was nearly zero. This was because NOx conversion of catalyst had slowed as time goes by due to black particles which had been adhered to the catalyst.

• Corrosion Science and Technology
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• v.19 no.2
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• pp.51-56
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• 2020

The objective of this study was to improve properties of plasma sprayed HAp layer to titanium substrate by introducing an intermediate layer with two different methods. Before applying Zn doped HAp coating on titanium substrate, an intermediate layer was introduced by titanium plasma spray or titanium anodization. Heat treatments were conducted for some samples after titanium intermediate layer was formed. Zn doped HAp top layer was applied by plasma spraying. Three-point bending test and pull-off adhesion test were performed to determine the adhesion of Zn doped HAp coatings to substrates. Long-term credibility of Zn doped HAp plasma sprayed coatings on titanium was assessed by electrochemical impedance measurements in Hanks' solution. It was found that both titanium plasma sprayed and titanium anodized intermediate layer had excellent credibility. Strong adhesion to the titanium substrate was confirmed after 12 weeks of immersion for coating samples with titanium plasma sprayed intermediate layer. Samples with titanium anodized intermediate layer showed good bending strength. However, they showed relatively poor resistance against pulling off. The thickness of titanium anodized intermediate layer can be controlled much more precisely than that of plasma sprayed one, which is important for practical application.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.546-551
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• 2024

As an effective methods of plasma heating, neutral beam injection (NBI) systems based on negative hydrogen ion sources will be utilized in future magnetic-confinement nuclear fusion experiments. Because of the collisions between the fast negative ions and the neutral background gas, the positive ions are inevitable created in the acceleration region in the negative NBI system. These positive ions are accelerated back into the ion source and become high energy backstreaming ions. In order to explore the characters of backstreaming ions, the track and power deposition of backstreaming H⁺ beam is estimated using the experimental and simulation methods at NNBI test facility. Results show that the flux of backstreaming positive ions is 1.93 % of that of negative ion extraction from ion source, and the magnet filed in the beam source has an effect on the backstreaming positive ions propagation.

• Journal of Welding and Joining
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• v.7 no.2
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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.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.6
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• pp.57-63
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• 2017

In this study, the fundamental test for drag reduction is carried out by using a plasma generator. Fundamental test setup is constructed of visualization and drag measurement system. The schlieren technique is used to visualize the plasma counterflow in supersonic flow. The penetration of the plasma jet and the change of the flow structure are observed through visualization results. Load cell is used to confirm possibility of drag reduction. Results show that drag was reduced by 6.2% using plasma jet in supersonic flow.

• Women's Health Nursing
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• v.7 no.1
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• pp.67-79
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• 2001

This study was designed to verify the effect of Doula-type-delivery nursing care on plasma $\beta$-endorphin, serum cortisol, related to delivery stress during labor, and postpartum anxiety of primipara by a quasi experiment(nonequivalent control group pretest-posttest design), from December, 1999 to August, 2000. The subjects of this experiment consisted of sixty eight primipara, with single gestation, full term, uncomplicated pregnancies, thirty three for the experimental group and thirty five for the control group. Their mean age was 26.1 years for the experimental group and 25.5 years for the control group. Their mean gestation period was 39.7 weeks for the experimental group and 40.1 weeks for the control group. As treatment, Doula-type-delivery nursing care was given for the experimental group. Data assessed plasma $\beta$-endorphin, serum cortisol during labor, and anxiety during postpartum. Plasma $\beta$-endorphin, serum cortisol were measured in the latent phase before treatment(pre-test) and the transition phase after treatment(posttest). Also, anxiety was measured in the latent phase before treatment(pre-test) and 24 hours postpartum after treatment(posttest). Data was analyzed by t-test, $x^2$-test, Repeated measures ANOVA with SAS Program. The results of this study were as follows; 1. Plasma $\beta$-endorphin was significantly elevated in the experimental group who were cared for with Doula-type-delivery nursing care during labor(P=.0463). 2. No significant group effects were found, but significant time effects were found for serum cortisol. 3. The postpartum anxiety of the experimental group was significantly lower than the control group(P=.0110). In conclusion, these findings indicate that Doula-type-delivery nursing care during labor could be effective in increasing maternal plasma $\beta$-endorphin and decreasing postpartum anxiety. Doula-type-delivery nursing care during labor could be applied as an effective nursing treatment for primipara.

• CELLMED
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• v.10 no.4
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• pp.30.1-30.4
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• 2020

Background: Tiryaq-e-arba is a polyherbal Unani antidote/antivenom formulation used in the management of poisoning due to snake bite, scorpion bite as well as in cold poisons since time immemorial. Objectives: Tiryaq-e-arba was not evaluated scientifically before this study carried out, therefore it was studied for antivenom activity by testing on plasma fibrinogen level in Russell's Viper envenomation in rabbits. Material &Methods: The anti-venom activity of the test drug was studied by observing its effect on plasma fibrinogen level in Russell's Viper envenomation in rabbits by the method of Netelson. Results: The plasma fibrinogen level was found to be 171±665.04 mg/100 ml of blood, 36.18±1.12 mg/100 ml of blood, 33.14±0.52 mg/100 ml of blood and 17.9±1.65 mg/100 ml of blood at 0, 1, 3 and 6 hours respectively in control animals while in the test animal it was found to be 157.13±3.44 mg/100 ml of blood, 41.13±2.69 mg/100 ml of blood, 62.09±1.65 mg/100 ml of blood and 54.39±0.73 mg/100 ml of blood respectively. The test showed that though the plasma fibrinogen level in the test lower at 0 hour but it was greater in the control animals at 1, 3 and 6 hours. The increase in plasma fibrinogen level in the test animals at 3 and 6 hours was statistically significant (P<0.001). Conclusions: The finding of the present study was that Tiryaq-e-arba possesses antivenom activity which scientifically support the Unani claim that it is Dafe-Sumoom-al-Hevan (Antivenom or Antidote) and the use of this preparation in corresponding diseases.