• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.147-150
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• 2002

The electron field emission properties of amorphous carbon (a-C) films deposited using a RF magnetron sputtering system have been improved by introducing a simple method of argon plasma treatment at room temperature. Surface morphologies and structural properties of the a-C films were investigated by scanning electron microscopy and Raman spectroscope, respectively. Structural properties and surface morphologies of the a-C films were changed by argon plasma treatment. The emission properties improved with the plasma treatment.

• Asian Journal of Atmospheric Environment
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• v.7 no.4
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• pp.199-208
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• 2013

Mercury exchange fluxes between atmosphere and soil surface were measured in two different types of soils; lawn soil (LS) and forest soil (FS). Average Hg emission from LS was higher than from FS although the soil Hg content was more than 2 times higher in forest soil. In LS, Hg emissions were much greater in warm season than in cold season; however, deposition was dominant in FS during warm season because of leafy trees blocking the solar radiation reaching on the soil surface. In both LS and FS, Hg fluxes showed significantly positive correlations with UV radiation and soil surface temperature during cold season. In addition, it was observed that emission showed positive correlation with UV radiation and soil temperature while there was negative relationship between deposition and UV radiation.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.286-289
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• 1987

The measurements of prebreakdown currents and breakdown voltages have been made for smooth rough, protrusion plane parallel stainless steel electrodes in vacuum ($10^{-5}$ torr), as a function of electrode separation, in the range $0.4{\sim}2.4mm$ using DC source($0{\sim}200KV$). Thee prebreakdwon currents of a each condition are found to be consistent with the Fouler-Nondheim field emission theory. The effect of the electrode surface condition on the local field enhancement factors, prebreakdown currents, and on the breakdown voltages are shown. The breakdown mechanism of a small vacuum gap was ascertained as the field emission corresponding the F-N theory. Therefore, these results suggest that the field emission currents following the electrode surface condition play a major role for initiation of DC breakdown.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.344-349
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• 2001

This paper was to investigate of a adhesiveness for the plasma sprayed coating materials did salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4,5wt.%Al and titanium dioxide powder Ti02. These powders were coated on a carbon steel S45C by plasma spray method. The salt solution was a 5% NaCl and the salt spray times were 2, 5 and 10 hours respectively. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spay. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increased.

• Asian Journal of Atmospheric Environment
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• v.11 no.3
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• pp.153-164
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• 2017

Odor dispersion around a cubic building from rooftop odor emissions was investigated using computational fluid dynamics (CFD). The Shear Stress Transport (here after SST) $k-{\omega}$ model in FLUENT CFD code was used to simulate the flow and odor dispersion around a cubic building. The CFD simulations were performed for three different configurations of cubic buildings comprised of one building, two buildings or three buildings. Five test emission rates were assumed as 1000 OU/s, 2000 OU/s, 3000 OU/s, 4000 OU/s and 5000 OU/s, respectively. Experimental data from wind tunnels obtained by previous studies are used to validate the numerical result of an isolated cubic building. The simulated flow and concentration results of neutral stability condition were compared with the wind tunnel experiments. The profile of streamline velocity and concentration simulation results show a reasonable level of agreement with wind tunnel data. In case of a two-building configuration, the result of emission rate 1000 OU/s illustrates the same plume behavior as a one-building configuration. However, the plume tends to the cover rooftop surface and windward facet of a downstream building as the emission rate increases. In case of a three-building configuration, low emission rates (<4000 OU/s) form a similar plume zone to that of a two-building configuration. However, the addition of a third building, with an emission rate of 5000 OU/s, creates a much greater odorous plume zone on the surface of second building in comparison with a two-building configuration.

• Journal of Information Display
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• v.6 no.4
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• pp.45-48
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• 2005

By applying a critical field treatment instead of the conventional surface treatments such as soft rubber roller, ion beam irradiation, adhesive taping, and laser irradiation, electron emission properties of screen-printed carbon nanotubes (CNTs) were enhanced and investigated based on the emission current-voltage characteristics through scanning electron microscopy. After nanotube emitters were activated at the applied electric-field of 2.5 V/um, the electron emission current density with good uniform emission sites reached the value of 2.13 mA/$cm^2$ , which is 400 times higher than that of the untreated sample, and the turn-on voltage decreased markedly from 700 to 460 V. In addition, enhancement of the alignment of CNTs to the vertical direction was observed.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.385-388
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• 1999

Electron field emission properties from various CVD diamond films were studied. Diamond films were synthesized by microwave plasma CVD at 1173K and at 673K substrates temperature and pulse microwave plasma CVD at 1173K. B-doped diamond film was synthesized by microwave plasma CVD at 1173K also. Estimation by SEM, both the non-doped diamond film and B-doped diamond film which were synthesized at 1173K substrate temperature were $2~3\mu\textrm{m}$ in diameter and nucleation densities were $10^{8}{\;}numbers/\textrm{cm}^2$ order. The diamond film synthesized at 673K was $0.2\mu\textrm{m}$ in diameter and nucleation densities was 109 numbers/cm2 order. The diamond film synthesized by pulse microwave plasma CVD at 1173K was $0.2\mu\textrm{m}$ in diameter and nucleation density was $10^{9}{\;}numbers/\textrm{cm}^2$ order either. From the result of electron field emission measurement, electron field emission at $20V/\mu\textrm{m}$ from CVD diamond film synthesized by pulse microwave plasma CVD was $37.3\mu\textrm{A}/\textrm{cm}^2$ and the diamond film showed the best field emission property comparison with other CVD diamond.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.448-454
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• 2001

Low field electron emission from novel carbon based cold cathodes is reported. The cathodes consisted of a layer of nanoseeded diamond and an over layer of nanocluster carbon films. The nanoseeded diamond was first coated on to thesubstrate. The nanocluster carbon films were then deposited on the nanocrystalline diamond coated substrates using the cathodic arc process at room temperature. The heterostructured microcathodes were observed to exhibit electron emission currents of 1 $\mu$A/cm$^2$ at fields as low as 1.5 to 2V/$\mu$m. The effect of the nanoseeded diamond size and concentration and the properties of different nanocluster carbon films on emission characteristics is presented.

• Journal of Korean Vacuum Science & Technology
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• v.5 no.1
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• pp.1-6
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• 2001

We measured the simultaneous, time-resolved spectra of photon emission, electron emission, and frictional force during the abrasion single crystal MgO with a diamond stylus in vacuum. phE and EE signal can be detected with millisecond resolution during the wear of a single crystal MgO substrate with a diamond stylus. The emissions and wear behavior are strong function of surface condition, load and stylus velocity. Measurement on annealed vs as-received material show that the luminescence is primarily due to deformation, and the electron emission is primarily due to fracture. These emissions provide insight into the processes responsible for catastrophic failure of ceramics in wear applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.483-483
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• 2012

Recently, nonthermal bioplasma has been attracted by researchers due to their potentials to modulate cellular functions resulting in changes of biomolecular electron band structures as well as cell morphologies. We have investigated the secondary electron emission characteristics from the surface of the erythrocyte, i.e., red blood cell (RBC) with and without the nonthermal bioplasma treatment in morphological and biomolecular aspects. The morphologies have been controlled by osmotic pressure and biomolecular structures were changed by well known reactive oxygen species. Ion-induced secondary electron emission coefficient have been measured by using gamma-focused ion beam (${\gamma}$-FIB) system, based on the quantum mechanical Auger neutralization theory. Our result suggests that the nonthermal bioplasma treatment on biological cells could result in change of the secondary electron emission coefficient characterizing the biomolecular valence band electron energy structures caused by the cell morphologies as well as its surface charge distributions.