• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.4
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• pp.213-218
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• 2009

Electrowinning process recovers uranium with actinide elements from spent fuels and is a key step in the Pyroprocessing because of proliferation resistance. An analysis of heat transfer of the Electrowinning cell was conducted to develop basic tool for designing engineering-scale Electrowinner. For the calculation of the heat transfer, ANSYS CFX commercial code was adapted. As a result of the calculation, the vertical Heating Zone length had great effect upon temperature of LiCl-KCl eutectic salt. To maintain constant temperature in the salt, the Heating Zone length should be three times longer than the height of the salt. However, the argon and salt temperatures were barely affected by the Cooling Zone length. The temperature under the Cell cover was mainly influenced by the number of the cooling plates. When the cooling plates were installed more than the number of 5, temperature under the cover was maintained below $250^{\circ}C$. These temperature properties had similar tendency toward the temperature of the Cell which was measured from experiments, Simulated heat transfer information from this study could be used to design engineering-scale Electrowinner.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.411-418
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• 1996

This experiment was conducted to investigate the effect of electric conductivity (EC) and potassium (K) concentration level in the culture solution on the growth and the air pollution monitoring capability of Perilla frutescens Suwon 16 which was recognized as a possible bioindicator for air pollution. The plants were exposed to $NO_2$, $O_3$, $SO_2$ and $NO_2+SO_2$ within a phytotron at $25^{\circ}C$ (day) or at $20^{\circ}C$(night) with 70% of relative humidity and evaluated the effect of EC and K level on the injury of the plants, The highest dry weights were gained as 16.3 g/plant at 0.5 dS/m of EC and as 32.3 g/plant at 100 and 200mg/l of K concentration, respectively. The diffusive resistances appeared as low values at 0.5 dS/m of EC and at 50, 100mg/l of K concentration. The increasing of the visible injury with increasing the dose of air pollutants could be taken at 0.5. 1.0 ds/m of EC and at 50, 100mg/l of K. The recommendable level of EC and K of the culture solution were 0.5-1.0 dS/m of electric conductivity. 50-100mg/l of K for the plant as an air pollutant biomonitor, when the 7th or 8th leaf was developed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.6
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• pp.278-282
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• 2010

The doping effect of thulium on electrical properties and degradation behavior in barium titanate ceramics ($BaTiO_3$) was investigated in terms of generations of core-shell structure and micro-chemical changes through highly accelerated degradation test. The dielectric specimens of pellet type and multi-layered sheets were prepared by using $BaTiO_3$ with undoped and doped with 1 mol% $Tm_2O_3$. The $BaTiO_3$ ceramics doped with 1 mol% $Tm_2O_3$ had 40% higher dielectric constant (${\varepsilon}$ = 2700) than that of the undoped $BaTiO_3$ specimen at curie temperature and met X7R specification. According to the result of highly accelerated degradation test conducted at $150^{\circ}C$, 70 V, and 24 hr, the oxygen diffusion was declined in dielectrics doped with 1 mol% $Tm_2O_3$. The $Tm^{3+}$ ion substituted selectively Ba site and Ti site and contributed to the generation of the core-shell structure. Oxygen vacancies occurred by substitution for Ti site could reduce excess oxygen that reacted to the Ni electrode.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.16-22
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• 2002

This paper suggests the optimum processing conditions for obtaining good quality $P^{+}$-n shallow junctions formed by pre-amorphization and furnace annealing(FA) to reflow BPSG(bore phosphosilicate glass). $BF_2$ions, the p-type dopant, were implanted with the energy of 20keV and the dose of 2$\times$10$^{15}$ cm$^{-2}$ into the substrates pre-amorphized by As or Ge ions with 45keV, 3$\times$$10^{14}$ $cm^{-2}$. High temperature annealings were performed with a furnace and a rapid thermal annealer. The temperature range of RTA was 950~$1050^{\circ}C$, and the furnace annealing was employed for BPSG reflow with the temperature of $850^{\circ}C$ for 40 minutes. To characterize the formed junctions, junction depth, sheet resistance and diode leakage current were measured. Considering the preamorphization species, Ge ion exhibited better results than As ion. Samples preamorphized with Ge ion and annealed with $1000^{\circ}C$ RTA showed the most excellent characteristics. When FA was included, Ge preamorphization with $1050^{\circ}C$ RTA plus FA showed the lowest product of sheet resistance and junction depth and exhibited the lowest leakage currents.

• Journal of the Korean Electrochemical Society
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• v.10 no.3
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• pp.207-212
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• 2007

[ $PSCF3737(Pr_{0.3}Sr_{0.7}Co_{0.3}Fe_{0.7}O_3)$ ] is a good candidate cathode material for IT-SOFC(intermediate temperature solid oxide fuel cell) because of high MIEC(mixed ionic electronic conductor) conductivity. In this study, the characteristics of PSCF3737 was investigated and optimizations of sintering temperature and thickness for $PSCF3737(Pr_{0.3}Sr_{0.7}Co_{0.3}Fe_{0.7}O_3)$ was carried out. Impedance responses were divided into two parts by frequency region. Middle frequency part (${\sim}10^2\;Hz$) was concerned with oxygen reduction reaction on surface and low frequency part (${\sim}10^{-1}\;Hz$) was related with oxygen diffusion. The reasonable sintering temperature and thickness of cathode were $1200^{\circ}C$ and about $27\;{\mu}m$ with regard to EIS(electrochemical impedance spectroscopy). ASR(areas specific resistance) of optimized cathode is $0.115\;{\Omega}\;cm^2$ at $700^{\circ}C$.

• Clean Technology
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• v.13 no.4
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• pp.293-299
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• 2007

Direct coating of catalyst layer on the $Nafion^{(R)}$ membrane has been optimized in the process of fabrication of membrane electrode assembly (MEA) to enhance the performance of direct methanol fuel cell (DMFC). In this method, the contact resistance at the interface of the catalyst layer and the membrane was found to be low. The effect of catalyst loading, thickness of membrane and the gas diffusion layer (GDL) with or without the presence of micro-porous layer (MPL) on the performance of the MEA was also investigated. The MEA fabricated by the above-mentioned method exhibited a performance of $147\;mW/cm^2$ and $100\;mW/cm^2$ at $80^{\circ}C$ and $60^{\circ}C$, respectively, with the catalysts loading of $4\;mg/cm^2$.

• Journal of the Korean Magnetics Society
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• v.13 no.3
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• pp.109-114
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• 2003

The purpose of this study Is to investigate the effect of $V_2$O$_{5}$ addition on the microstructures and magnetic properties of 7.7${\times}$4.5${\times}$1.0 mm sized multi-layer chip inductors prepared by the screen printing method using 0∼0.5 wt％ $V_2O_{5}$-doped NiCuZn ferrite pastes. With increasing the $V_2O_{5}$ content, the exaggerated grain growth of ferrite layers was developed due to the promotion of Ag diffusion and Cu segregation into the grain boundaries oi ferrites, which affected significantly the magnetic properties of the chip inductors. After sintering at $900^{\circ}C$, the inductance at 10 MHZ of the 0.5 wt％ $V_2O_{5}$-doped chip inductor was 3.7 ${\mu}$H less than 4.2 ${\mu}$H of the 0.3 wt% $V_2O_{5}$-doped one, which was thought to be caused by the residual stress at the ferrite layers increased with the promotion of Ag diffusion and Cu segregation. The quality factor of the 0.5 wt% $V_2O_{5}$-doped chip inductor decreased with increasing the sintering temperature, which was considered to be caused by the electrical resistivity of the ferrite layer decreased with the promotion of Ag/cu segregation at the grain boundaries and the growth of the mean grain size of ferrite due to exaggerated grain growth of ferrite layers.

• Research in Plant Disease
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• v.24 no.1
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• pp.41-51
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• 2018

Since fire blight disease on apple and pear was produced in Korea in 2015, there were no registered chemicals to control against this disease. Instead, several antibacterial chemicals that were registered for other bacterial diseases such as soft rot and bacterial spot have been authorized by Rural Development Administration (RDA). However, these chemicals are not tested efficacy for fire blight disease except damage by those treatments on apple and pear in Korea. Thus, we evaluated efficiency using in vitro and in planta assays of antibacterial chemicals such as antibiotics and copper compounds including kasugamycin, oxytetracycline, oxolinic acid and streptomycin, and copper hydroxide, copper sulfate, oxine copper and tribasic copper sulfate, respectively. We also tested two kinds of biological agents. As expected, significant antibacterial effect was observed in vitro test of both antibiotics and copper-based chemicals. In planta test based on disease severity including ooze and water-soaked formation on immature pears, bacterial populations on blooms, and blight lesion formation in artificially inoculated shoots, kasugamycin, oxytetracycline and streptomycin have been shown the most efficiency among tested antibiotics. Four copper-based chemicals tested in this study, control effects are little bit lower than agricultural antibiotics but they seem to be available to use in terms of winter season. Biocontrol agents were also shown possibility to treat in eco-friendly farms. In addition, there are no antibiotic resistance genes in Korean isolates against antibiotics, which were selected for suppression of fire blight in this study.

• Korean Security Journal
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• no.31
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• pp.125-155
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• 2012

Terrorist organization has shown the trend of secret organization and it is harder to cope with terrorism because of uncertainty of terrorism. Homegrown terrorism is the one, whose preparation, execution and effect are restricted to domestic area. By the way, in the worldwide economic depression, violence and radical demonstration have shown the expansion trends as in Middle East, political revolution of Africa, anti-social resistance of Europe and Wall Street Occupation of USA. Homegrown terrorism is occurring in various countries such as UK and Spain as well as USA. Specialists warn homegrown terrorism in Korea. The purpose of this study was to prospect the possibility of homegrown terrorism that can be generated in the transfer to multi-culture society as various foreigners come to Korea rapidly and suggest the method to cope with the trend. The study analyzed environment and analysis of homegrown terrorism that Korea faces now. The methods to cope with homegrown terrorism are as follows. First, distribution of radical homegrown terrorism via internet should be prevented. Second, the connection between terrorist organization and homegrown terrorist should be prevented. Third, there should be a cooperation among government, residents and religious group. Fourth, there should be an open approach against multi-culture society. Fifth, there should be a systematic control for cause of new conflict. Finally, there should be a long-term approach to cause of new conflict. If we do not make an effort to prevent homegrown terrorism, terrorism environment may face new aspect and national and social cost for it will increase.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.278-283
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• 2020

Central sleep apnea (CSA) is characterized by respiratory failure of at least 10 seconds without any effort of the chest and abdomen in the absence of upper airway resistance during sleep. In this case, the patient experiences respiratory failure that does not meet the CSA diagnostic criteria and CSA symptoms. Magnetic resonance imaging diffusion-weighted imaging (MRI DWI) scans revealed a lateral medullary infarction. Continuous positive airway pressure (CPAP) was applied as a primary treatment for CSA and respiratory failure. During the titration of CPAP, the apnea-hypopnea index (AHI) and arousal index (AI) were worse than the results before its use (AHI: 42.5/hr→82.8/hr, AI: 21.7/hr→40.8h). As a result, adaptive servo-ventilation (ASV) was chosen as the secondary treatment. Compared to the night-polysomnography results before the ASV treatment, the AHI improved (42.5/hr→8.6/hr). Therefore, ASV is a potential treatment for CSA and respiratory failure in these patients.