• Journal of Energy Engineering
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• v.24 no.4
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• pp.175-182
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• 2015

A methodology to determine the most conservative initial condition based on random sampling of operation parameters is established, in which a best-estimate computer code is adopted to minimize the conservatism in code models. To validate the applicability of the suggested method, safety evaluation for a transient of loss of condenser vacuum in a pressurized water reactor is performed. One-hundred different initial conditions are generated by MOSAIQUE program automatically and the peak pressure for the most conservative case is determined from transient analyses. The safety margin obtained with the new approach is almost equivalent to the values determined with the existing methodologies. It is found that the time and human resources required for the safety evaluation could be reduced with the suggested approach.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.337-337
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• 2011

Application of plasma technology on microbial sterilization has been frequently studied. In spite of accumulating number of studies, many have been focused on bacteria. Reports on eukaryotic yeasts and filamentous fungi are limited. In addition, mechanism of plasma effect still needs to be clarified. In this study, we analyzed the effect of non-thermal atmospheric pressure plasma on the budding yeast, Saccharomyces cerevisiae using DBD-type device. When yeast cells were exposed to plasma (at 2 mm distance) and then cultured on YPD-agar plate, number of cells survived (shown as colony) were reduced proportionally to exposure time. More than 50% reduction in number of colonies were observed after twice exposure of 5min. each. Colonies much smaller than those of control (no plasma exposure) were appeared after twice exposure of 5 min. each. It seems that small colonies are resulted from delayed cell growth due to the damage caused by plasma treatment. Microscopic analysis demonstrates that yeast cells treated with plasma for 5 min. twice have more rough and shrinked shape compared to oval shape with smooth surface of control.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.168-168
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• 2010

Transparent conduction oxides (TCOs) films is extensively reported for optoelectronic devices application such as touch panels, solar cells, liquid crystal displays (LCDs), and organic light emitting diodes(OLEDs). Among the many TCO film, indium tin oxide(ITO) is in great demand due to the growth of flat panel display industry. However, indium is not only high cost but also its deposits dwindling. Therefore, many studies are being done on the transparent conductive oxides(TCOs). We fabricated a target of IZTO(In2O3:ZnO:SnO2=70:15:15 wt.%) reduced indium. Then, IZTO thin films were deposited on glass substrates by pulsed DC magnetron sputtering with various oxygen flow ratio. The substrate temperature was fixed at the room temperature. We investigated the electrical, optical, structural properties of IZTO thin films. The electrical properties of IZTO thin films were dependent on the oxygen partial pressure. As a result, the most excellent properties of IZTO thin films were obtained at the 3% of oxygen flow rate with the low resistivity of $7.236{\times}10^{-4}{\Omega}cm$. And also the optical properties of IZTO thin films were shown the good transmittance over 80%. These IZTO thin films were used to fabricated organic light emitting diodes(OLEDs) as anode and the device performances studied. The OLED with an IZTO anode deposited at optimized deposition condition showed good brightness properties. Therefore, IZTO has utility value of TCO electrode although it reduced indium and we expect it is possible for the IZTO to apply to flexible display due to the low processing temperature.

• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.3-12
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• 2001

This study conducted to Investigate the movement of fertilized nutrients in a volcanic ash soil in Jeju using by the pressure-vacuum soil water sampler. The percolated water to measure the ion concentration of leachates was taken from a lysimeter at depths of 20, 40, 60, 80, 100 and 120 cm in the soil in where a corn and potato were cultivated as a preceding and succeeding crop, respectively. Fertilizers of N-$P_2$O$_{5}$-$K_2$O were applied at the rate of 36-30-30 kg $10a^{-1}$ for the corn and 28-22-24 kg $10a^{-1}$ for the potato prior to planting of both crops. The highest concentrations of Cl , $NO_3$-N, $Ca^{+2}$ and $K^+$ in percolates were showed at 20cm and 40cm in soil depth at one month after fertilizing, and then gradually moved and reduced into below soil depths. At 5.5 months after fertilization, the concentrations in all soil depths were similar with the value of before fertilization. At depth of 120cm, the concentration of NO$_3$-N and the other cations in leachate was highest 1 to 1.5 months after fertilization. pH in percolated water was negatively correlated with NO$_3$-N concentration while the concentration of $NO_3$-N showed positive correlation between Cl, $Ca^{+2}$ and $Mg^{+2}$ concentrations. This result indicated that those cations can be leached out by accompanied with $NO_3$-N.

• KSBB Journal
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• v.16 no.3
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• pp.233-236
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• 2001

Because of casehardenign effect of amorphous paclitaxel, residual solvents, methylene chloride and emthanol could not be reduced to the maximum value allowed, 600 ppm and 3,000 ppm, in accord with the guidelines issued by the International Conference on Harmonization (ICH, 1997), using rotary evaporation and successive drying in a vacuum oven. However, methylene chloride and methanol were reduced to 486 ppm and 403 ppm, respectively using supercritical $CO_2$ on purified paclitaxel. The optimum pressure and operating time were 80 bar and 30 min at fixed operating temperature ($40^{circ}C$). This approach serves as a novel application of supercritical fluid extraction to remove residual solvents from active pharmaceutical ingredients.

• 보존과학연구
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• s.13
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• pp.69-80
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• 1992

A great numbers of cultural properties destroyed though attack by insect pests and microorganisms. Biodeterioration damage is particularly serious in this country because many cultural propertiese are made of organic materials. Recently, there are various countermeasures of biodeterioration or alternative methods are reported, such as Gamma Radiation, Micro-wave Irridation, Freezing, Inert Atmosphere (Oxygen-less atmosphere), and Environmental Control. However its practical application are limited and some difficulties for treatment of large objects. Fumigation is one of the most useful and effective methods of control biodeterioration because it gives less damage of cultural properties but rapidly eradicate infesting organisms at one action. This paper evaluated selected fumigants and fumigation methods with emphasis on the following paragraph:1) Effectiveness of selected fumigants on insects and microbes involved inbiodeterioration.2) Physical and chemical characters of selected fumigants.3) Less toxic new alternative fumigant and its mixtures.4) Inert atmosphere (Oxygen-less atmosphere)5) Methods of fumigation : Sealed fumigation, Covered fumigation and Vacuum fumigation (Reduced-pressure fumigation)

• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.132-139
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• 2011

This study examined the characteristics of radio-frequency/vacuum dried Korean red pine ($Pinus$ $densoflora$) heavy timbers with 250 ${\times}$ 250 mm (S), 300 ${\times}$ 300 mm (L) in cross section and 300 mm in diameter, and 3,600 mm in length, which were subjected to compressive loading after a kerf pretreatment. The following results were obtained : The drying time was short and the drying rate was high in spite of the large cross section of specimens. The moisture gradient inall specimens was gentle in both longitudinal and transverse directions owing to dielectric heating. The shrinkage of the width in the direction perpendicular to was 21 percent ~ 76 percent of that of the thickness of square timbers in the direction parallel to the mechanical pressure. The casehardening for all specimens was very slight because of significantly reduced ratio of the tangential to radial shrinkage of specimens and kerfing. The surface checks somewhat severely occurred although the occurrence extent of the surface checks on the kerfed specimens was slight compared withthat on the control specimen.

• Journal of the Korean Magnetics Society
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• v.10 no.1
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• pp.11-15
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• 2000

13Cr-1.5Nb-Fe alloy powder prepared by water atomizing method is reduced with flowing hydrogen gas. The characteristics of a reduced alloy powder is investigated and magnetic cores formed by using the reduction power sintered in the vacuum of ∼10$\^$-5/ Torr. In order to study on the magnetic cores permeability and power loss in alternating magnetic field are also measured. The result of particle size distribution shows the paticle size is 70 ㎛ at volume fraction of 50 %. The saturation magnetization of the reduced alloy powder is 160 emu/g. The relative peak permeability (H$\_$a/=5Oe) of a magnetic core is 400 and the power loss (B$\_$m/=80G) 0.12 mW/cc at sintering temperature of 1,200 $\^{C}$, 10 ton/㎠ forming pressure, and 1 kHz.

• Korean Journal of Materials Research
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• v.19 no.2
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• pp.68-72
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• 2009

This study investigated dry etching of acrylic in capacitively coupled $SF_6$, $SF_6/O_2$ and $SF_6/CH_4$ plasma under a low vacuum pressure. The process pressure was 100 mTorr and the total gas flow rate was fixed at 10 sccm. The process variables were the RIE chuck power and the plasma gas composition. The RIE chuck power varied in the range of $25{\sim}150\;W$. $SF_6/O_2$ plasma produced higher etch rates of acrylic than pure $SF_6$ and $O_2$ at a fixed total flow rate. 5 sccm $SF_6$/5 sccm $O_2$ provided $0.11{\mu}m$/min and $1.16{\mu}m$/min at 25W and 150W RIE of chuck power, respectively. The results were nearly 2.9 times higher compared to those at pure $SF_6$ plasma etching. Additionally, mixed plasma of $SF_6/CH_4$ reduced the etch rate of acrylic. 5 sccm $SF_6$/5 sccm $CH_4$ plasma resulted in $0.02{\mu}m$/min and $0.07{\mu}m$/min at 25W and 150W RIE of chuck power. The etch selectivity of acrylic to photoresist was higher in $SF_6/O_2$ plasma than in pure $SF_6$ or $SF_6/CH_4$ plasma. The maximum RMS roughness (7.6 nm) of an etched acrylic surface was found to be 50% $O_2$ in $SF_6/O_2$ plasma. Besides the process regime, the RMS roughness of acrylic was approximately $3{\sim}4\;nm$ at different percentages of $O_2$ with a chuck power of 100W RIE in $SF_6/O_2$ plasma etching.

• Analytical Science and Technology
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• v.27 no.4
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• pp.187-195
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• 2014

It is very important to minimize the damage of latent fingerprints at enhancing the contrast. This study proves the enhancement effects of cyanoacrylate-fumed latent fingerprints using p-dimethylaminobenzealdehyde (DMAB) on semi-porous surfaces and the influence factors. The latent fingerprints in experiment were developed for cyanoacrylate treatment in a vacuum chamber and used after drying at room temperature for 24 hours. For fluorescence staining, the cyanoacrylate-developed marks using DMAB were sublimated during 48 hours under the different conditions of surface area, temperature, atmospheric pressure. First experiment showed how surface area effects on the sublimation rate and fluorescence intensity by DMAB of particle size and container size. In addition, the fluorescence staining using DMAB with solvent-free contact method had the greatest fluorescence intensity after 36 hours and a low fluorescence intensity over a certain size of surface area. Second experiment showed that the evaporation of DMAB solid crystals got a satisfying result in a temperature of $20^{\circ}C$ and reduced time to get the greatest fluorescence intensity. It took a long time to get a optimum level of fluorescence intensity at $30^{\circ}C$ or more and it was less effective in fluorescence intensity. Third experiment on the pressure indicated that the fluorescence intensity of vacuum was weaker than nonvacuum but it was inapplicable to very high variations in pressure.