• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.28-31
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• 2018

In display and semi-conductor manufacturing process, there are numerous unstable factors such as particle concentration, minimal vibration, changes in magnetic field, or electrostatic that becomes an issue to be managed and controlled. In the recent, X-ray ionization is widely used that is neutralized by separating air or gas molecules in the area where the static must be resolved. The mono-type of X-ray ionizer was not capable to be used in $8^{th}$ generation panels manufacturing plant due to its insufficient ionizing coverage since the panel itself is approximately in $2m{\times}3m$. To resolve the current problem, the development of new type called, "Multi-type X-ray ionizer" has resulted in covering enough ionizing space in $8^{th}$ generation panels industry. Comparing mono and multi types with MCNPX code simulation, the multi one indicates more X-ray flux, efficiency, and ionization performance in comparison with either a mono-type or multi-type in array format. In addition, the ionizing efficiency of overlapping area with multi-type showed 30% higher effectiveness rate as to the ordinary mono-type.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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• pp.650-657
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• 2007

This paper had mentioned about CCP light source application for increasing the efficiency of Xe lamp the mercury-free lamp. In order to increase the efficiency of Xe EEFL, we designed and manufactured the lamp used by mixture gas of Xe, Ne and He. Also, we have analyzed the electrical and optical properties with the firing voltage, sustain voltage, paschen's curve, wall charge, and capacitance. As a result, the firing voltage decreased by increasing the ration of mixture gas. and, It is owing to include the gas with high ionization energy. The firing voltage decreased in condition happening the penning effect, Because the ion of metastable state created from penning effect, Which can encourage the ionization phenomena. Also, the wavelength of 467.12 is increase. because of the energy transition in the wavelength of 147 nm. therefore, we can know about the affection of phosphor with UV emission properties. Through an experiment, Xe 100 % and Xe 75 % confirmed same spectrum properties by each mixture gas ratio. In the case of Xe 50 %, spectrum properties appeared Xe discharge and Ne-He discharge. That analyzed an electrical and optical properties. Therefore, confirmed that is excellent because properties of firing voltage, wall charge, capacitance in Xe 50 %, Ne : He = 9 : 1. We offered parameter in inverter manufacture and lamp manufacture by electrical and optical properties.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.367-377
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• 2001

Plasma is generated by electrical discharge. Most plasma generation has been carried out at low-pressure gas typically less than one millionth of atmospheric pressure. Plasmas are in general generated from impact ionization of neutral gas molecules by accelerated electrons. The energy gain of electrons accelerated in an electrical field is proportional to the mean free path. Electrons gain more energy at low-pressure gas and generate plasma easily by ionization of neutrals, because the mean free path is longer. For this reason conventional plasma generation is carried out at low pressures. However, many practical applications require plasmas at high-pressure. In order to avoid the requirement for vacuum pumps, researchers in Korea start to develop plasmas in high-pressure chambers where the pressure is 1 atmosphere or greater. Material processing, environmental protection/restoration and improved energy production efficiency using plasmas are only possible for inexpensive bulk plasmas. We thus generate plasmas by new methods and plan to set foundations for new plasma technologies for $21^{st}$ / century industries. This technological research will play a central role in material processing, environmental and energy production industries.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.927-931
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• 2010

Recently, high luminance and high efficiency were realized in OLED with multilayer structure including emitting materials such as metal-chelate complexes. We synthesized a new luminescent material, namely, [2-(2-hydroxyphenyl)quinoline] (Zn(HPB)q) which has low molecular compound and emitted in yellowish green region. The ionization potential(IP) and electron affinity(EA) of Zn(HPB)q were measured by cyclic-voltammetry(CV). As a result, IP and EA of Zn(HPB)q were calculated 6.8 eV and 3.5 eV, respectively. We fabricated the devices and observed the possibility of Zn(HPB)q as electron transporting layer. We have obtained an improvement of luminance and decrease of turn-on voltage using Zn(HPB)q as electron transporting layer.

• Journal of Korean Society on Water Environment
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• v.30 no.2
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• pp.175-183
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• 2014

The influence of temperature on the treatment efficiency of chlorinated organic substances contained in groundwater by permeable reactive barrier which is composed of $Fe^{\circ}$ has been investigated by constructing the Pourbaix diagrams for Fe-$H_2O$ system at different temperatures based on thermodynamic estimation. In aerobic condition, the equilibrium potentials for $Fe^{\circ}/Fe^{2+}$ and $Fe^{2+}/Fe^{3+}$ were observed to increase, therefore, the dechlorination reaction for organic pollutants by $Fe^{\circ}$ was considered to decline with temperature due to the diminished oxidation of reactive barrier. The result for the variations of the ionization fraction of $Fe^{2+}$ and $Fe^{3+}$ ion in the pH range of 0 ~ 2.5 obtained by employing Visual MINTEQ program showed that the ionization fraction of $Fe^{2+}$ increased with pH, however, that of $Fe^{3+}$ decreased symmetrically and the extent of the variation of ionization fraction for both ions was raised as temperature rises. The equilibrium pH for $Fe^{3+}/Fe(OH)_3$ was examined to decrease with temperature so that the treatment efficiency of chlorinated organic substance was expected to decrease with temperature due to the enhanced formation of passivating film in aerobic condition. The change of the reactivity of a specific chemical species with temperature was defined quantitatively based on the area of its stable region in Pourbaix diagram and depending on this the reactivity of $Fe^{3+}$ was shown to decrease with temperature, however, that of $Fe(OH)_3$ was decreased monotonously as temperature is raised for $Fe^{3+}/Fe(OH)_3$ equilibrium system. In anaerobic condition, the equilibrium potential for $Fe^{\circ}/Fe^{2+}$ was observed to rise and the equilibrium pH for $Fe^{2+}/Fe(OH)_2$ were examined to decrease as temperature increases, therefore, similar to that for aerobic condition the efficiency of the dechlorination reaction for organic substances was considered to be diminished when temperature rises because of the reduced oxidation of $Fe^{\circ}$ and increased formation of $Fe(OH)_2$ passivating film.

• Journal of the Korean Graphic Arts Communication Society
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• v.11 no.1
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• pp.103-122
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• 1993

A cause and counterplan of the increase in dark decay rate of$\varepsilon$-CuPc/PVCz photoreceptor which is consist of the carrier generation layer (CGL) of$\varepsilon$type copper phthalocyanine ($\varepsilon$-CuPc) thin film by an aqueous coating method and the carrier transport layer (CTL) of polyvinylcarbazol (PVCz) by spin coating, are studied in this paper. Electrochemical deposition of CGL was accompanied by an increase in work function of the aluminium substrate during the processes and the enhanced work function 5.3 eV rose above the ionization potential 5.16 eV of $\varepsilon$-CuPc. This resulted in the increased injection of holes from substrate into CGL and a fast dark decay rate. Improved photoreceptor, an electron-transport $\varepsilon$-CuPc/TNF photoreceptor, led to lowing of dark decay rate and increasing of photosensitivity. The carrier generation efficiency (ηg), carrier injection efficiency (ηi) and xerographic gain (G) of the $\varepsilon$-CuPc/TNF photoreceptor were obtained by XTOF method and PIDC.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.71-76
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• 2001

An electret filter is composed of permanently charged electet fibers and is widely used in applications requiring high collection efficiency and low-pressure drop. In this work, the collection efficiency of the filter media used in manufacturing cabin air filters was investigated by using poly-disperse particles when submicron particles are loaded. Long-term experiments were conducted by applying different charging states, which are spray electrification and charge equilibrium by bipolar ionization. In order to investigate on the effect of particle loading in filter media, NaCl particles were generated from 0.1% and 1% solutions by an atomizer. In NaCl 0.1%, the collection efficiency of electret filter decreased and then did not change in equilibrium state. In the case of relative larger particles of NaCl 1%, collection efficiency for the equilibrium charged particles increases due to the particle loading on the filter fibers. Particles charged by spray electrification are small in collection efficiency after equilibrium state and increase of filter media's pressure drop was very low in comparison of the equilibrium charged particles.

• Analytical Science and Technology
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• v.23 no.5
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• pp.498-504
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• 2010

It is very difficult to get stable ion peak intensity of ruthenium by thermal ionization mass spectrometry because of its high ionization potential and high volatility of its oxides which causes to lose much of ruthenium ions, so the intensity of the signal decrease quickly. Accordingly, a study was performed in oder to increase the ionization efficiency and to prevent sample losses due to volatilization and to check with isobaric effect by impurities in filament for the measurement of ruthenium isotopes. Both single filament and double filament were tested. The former was proved to be more efficient for the stable and strong intensity of signal and revealed less isobaric effect from the molybdenum (Mo) as a filament impurity. Also, when the temperature of filament increased too high, the isobaric effect from Mo greatly appeared. That is, Mo impurity from filament gave a serious effect for measuring the ruthenium isotopes. It was proved to be of importance that filament current should be slowly increased with time interval. Finally, ruthenium isotopes were accurately measured by correction with measuring $^{94}Mo/^{99}Ru$.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.121-126
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• 1999

Cu thin film was deposited by a self-ion assisted beam source (SIAB) and the assessment of the Cu films was given. Some characteristics of the source and the experimental procedure are described at various conditions such as total power, ionization efficiency, and ion current vs. deposition rate. The dependence of crystalline structure, impurity concentration, and resistivity of the Cu films deposited by SIAB on acceleration voltage are discussed.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.670-699
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• 2016

In this study, 16 antibiotics were selected from among the top 30 veterinary antibiotics sold in South Korea in 2014, as well as from among the pharmaceuticals targeted by EPA method 1694, in order to review analytical methods for the detection of trace levels of antibiotics in environmental samples: surface water, soils, animal origin foods, and manures. LC-MS/MS was heavily used. In the chromatography for the detection of the selected antibiotics, the $C_{18}$ column was mostly used at the temperature of $30{\sim}40^{\circ}C$. Water and methanol/acetonitrile were commonly chosen as a nonpolar and a polar mobile phase, respectively. Gradient elution was applied to separate multiclass antibiotics. Volatile additives, such as formic acid, acetic acid, and ammonium acetate were mixed with the mobile phase to improve the ionization efficiency of analytes and the sensitivity in MS detection. Electrospray ionization (ESI) was widely used in the LC-MS/MS and positive ionization was preferred to determine the selected antibiotics. A protonated $[M+H]^+$ molecule was selected as a precursor ion, and its two transitions were analyzed, one for quantitative measurement and the other for confirmation. This study reviewed linearity of the calibration curve, recovery, repeatability, method detection limits (MDLs), and method quantification limits (MQLs) for each target compound used to validate the developed analytical methods.