• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.369-369
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• 2011

In the current work, we demonstrate the gas phase plasma synthesis of ultrafine boron nanoparticles by decomposing boron trichloride (BCl3) gas in an argon-hydrogen thermal plasma and quenching the hot plasma by expansion through a ceramic nozzle, driving the homogeneous nucleation of nanoparticles. It is shown that ultrafine nanoparticles can be produced from the experiments. We also show the characterization results regarding the oxidation of boron nanoparticles at room temperature using X-ray Photoelectron Spectroscopy (XPS) and the combined Scanning Transmission Electron Microscope (STEM) and Electron Energy Loss Spectroscopy (EELS).

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.278-282
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• 1987

Computational and theoritical investigations of an arc plasma have been made for the design of a circuit breaker. Modeling of an arc plasma used to be very involved and difficult because of the many variables and factors, In this paper, the dynamic behavior of an arc plasma is investigated by solving the MHD equations. Comparing an $SF_6$-blast arc with a non-blast arc, it has been found that the effect of gas-blast has a great influence on density rather than temperature.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.415-425
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• 1996

This study presents an analytical method of solving the behaviors of arc plasma in a nozzle constricting transferred-type torch and purposes to obtain the basic data for the design of a plasma torch, which can be obtained from the temperature, pressure, velocities and voltage distributions. We have to solve some conservation equations simultaneously and need to know the exact thermal gas properties in order to obtain the correct behaviors of arc plasma. It is also necessary to give the relevant physical or geometric boundary conditions. For the simplicity of analysis, we assumed that (a) the plasma flow is laminar, (b)the local thermodynamic equilibrium, i.e. LTE, prevails over the entire arc column region. The electrode sheath effects were neglected and the nozzle area was excluded from the analysis by assuming that the current flow into the nozzle is zero. We solved the momentum transfer equation including the self-magnetic pinch effect, and obtained the temperature distribution from the energy conservation equation. From this temperature, we could get arc voltage distribution. (author). refs., figs., tabs.

• Carbon letters
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• v.5 no.3
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• pp.103-107
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• 2004

The atmospheric pressure plasma treatments ($Ar/O_2$ and $Ar/N_2$) of activated carbon fibers (ACFs) were carried out to introduce hydrophilic functional groups on carbon surfaces in order to enhance the hydrogen chloride gas (HCl) adsorption. Surface properties of the ACFs were determined by XPS and SEM. $N_2$/77 K adsorption isotherms were investigated by BET and D-R (Dubinin-Radushkevich) plot methods. The HCl removal efficiency was confirmed by HCl detecting tubes (range:1~40 or 40~1000 ppm). As experimental results, it was found that all plasma-treated ACFs showed the decrease in the pore volume, but the HCl removal efficiency showed higher level than that of the untreated ACFs. This result indicated that the plasma treatments led to the conformation of hydrophilic functional groups on the carbon surfaces, resulting in the increase of the interaction between the ACFs and HCl gas.

• Journal of the Korean institute of surface engineering
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• v.23 no.4
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• pp.218-224
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• 1990

Silicon nitride thin(SiNx) is deposited onto 3 inch silicon wafor using ECR plasma apparatus. For the two different plasma extraction windows size, the thin films which were deposited by changing the SiH4/N2 gas fole at at 1.5mTorr without substrate heating are analyzed through the XPS and wlliposometer measurements. The very uniform and good quality silicon nitride thin film were obtained with the analyzed results of the deposited films, and particularly, ion temperature perpendicular to the magnetic filed was nearly same as the neutral gas temperature. The large amount of plasma loss in the transport process following magnetic field lines could be seen from the plasma emission intensity measurements.

• Textile Coloration and Finishing
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• v.2 no.3
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• pp.8-13
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• 1990

In order to study the modification of wettability, tactility, and bathochromicity of the poly (ethylene Terephthalate) (PET) fabrics, low-temperature plasma$(O_2)$ has been irradiated on the PET fabrics in various conditions. The results obtained from this study were as follows; 1) The weight loss rate of plasma-treated PET fabrics is proportional to irradiation time and internal gas temperature of treating chamber. Also, the effect of weight loss is remarkable at gas pressure ranging from 3 torr to 5 torr. 2) The bathochromic effect of PET fabrics treated with low-temperature plasma$(O_2)$ was improved.

• Bulletin of the Korean Chemical Society
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• v.19 no.5
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• pp.524-526
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• 1998

A sensitive and specific method is described for the determination of midazolam in human plasma. The drug was extracted from 1 mL of carbonate buffered plasma (pH 9.6) with 8 mL of diethyl ether. Famprofazone was used as internal standard. The organic phase was evaporated to dryness. The residue was dissolved in methanol for the direct analysis by gas chromatograph-nitrogen phosphorus detector system. In the concentration range of 1-5000 ng/mL, the calibration curve was linear. The coefficients of variation from the precision test were <6% at the range of the concentration of 0.10-2.00 μg/mL and the detection limit for midazolam in 1 mL of plasma was o.5 ng. This assay is more sensitive, selective, simple and rapid than earlier methods. Plasma midazolam concentrations were determined by this method after administration of midazolam.

• Bulletin of the Korean Chemical Society
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• v.14 no.2
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• pp.275-281
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• 1993

The new high temperature plasma source for spectrochemical analysis has been developed and characterized. In the development of new high temperature plasma sources for atomic emission spectrocopy, optimization of experimental variables is necessary to achieve the best analytical results. By means of a modified sequential simplex optimization method, six experimental variables were optimized. The line-to-background (L/B) ratio for Ca(II) at 393.37 nm was used as measure of the response function. The optimal experimental conditions were found to be at a current of 27.8 A, a plasma length of 28.8 mm, a sample uptake rate of 1.3 ml/min, a sample carrier gas flow rate of 0.7 ml/min, a plasma gas flow rate of 4.9 l/min, and an observation height of 6.4 mm above the top quartz tube.

• Resources Recycling
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• v.13 no.1
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• pp.59-67
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• 2004

A universal plasma-chemical module (PChM) for the industrial processing of different hydrocarbon raw material pyrolysis was designed and tested. Laboratory investigations for the plasma-chemical method of acetylene production from natural gas and different coals were made. Similar laboratory tests on the industrial production of acetylene as a raw material for organic syn-thesis were developed using the PChM. A comparison of the suggested plasma-chemical method with the traditional process of acetylene production were carried out. The outlook of the plasma-chemical method was shown.

• Journal of Korea Foundry Society
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• v.15 no.2
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• pp.175-183
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• 1995

It is difficult to remove such interstitial impurities as sulfur, oxygen, hydrogen and carbon in Fe-Ni alloys. Thermodynamic and kinetic studies were carried out on the behavior of hydrogen gas, oxygen gas, Si, Al and slag, and the reaction time by the $Ar/Ar-H_2$ plasma and electron beam melting. After the addition of Al, Si, they were melted by Ar plasma with reaction time changed. 80%Ni-Fe alloys showed a better deoxidation than 36%Ni-Fe alloys. At $Ar-H_2$ plasma melting, the deoxidation was significant. In the case of the electron beam melting, the residual oxygen was higher than in Ar plasma melting because electron beam melting temperature was lower than that of Ar plasma. For the decaburization, it was melted by $Ar-O_2$ plasma melting, which could remove effectively carbon by activated oxygen in plasma. We added slag to Fe-Ni alloys for the desulfurization. As the result of this experiments, the amount of residual sulfur was not changed according to the slag ratio and reaction time.