• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.106-110
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• 2002

Gel-type polyacrylonitrile(PAN) polymer electrolytes have been prepared using ethylene carbonate(EC), propylene carbonate(PC) and dimethyl carbonate(DMC) plasticizer, $LiPF_6$ salt and $TiO_2$ ceramic filler. Electrochemical properties, such as electrochemical stability, ionic conductivity and compatibility with lithium metal and mechanical properly of polymer electrolytes were investigated. Charge/discharge performance of lithium secondary battery using these polymer electrolytes were investigated. The maximum load that the polymer electrolyte resists increased about two times as a result of adding $TiO_2$ in the polymer electrolyte containing EC and PC. Polymer electrolyte containing EC, PC and $TiO_2$ also showed ionic conductivity of $2\times10^{-3} S/cm$ at room temperature and electrochemical stability window up to 와 4.5V. Polymer electrolyte containing EC, PC, and $TiO_2$ showed the most stable interfacial resistance of $130\Omega$ during 20 days in the impedance spectra of the cells which were constructed by lithium metals as electrodes. Lithium metal secondary battery which employed $LiCoO_2$ cathode, lithium metal anode and $TiO_2$-dispersed polymer electrolyte showed $90\%$ of charge/discharge efficiency at the 1C rate of discharge.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.316-316
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• 2017

The objective of this study is to estimate quantitatively soil salinity and soil loss at upland soils in agriculture land region in Saemangeum reclaimed land on the south Korea coasts. Soil loss and soil salinity are the most critical problem at reclaimed tidal saline soil in Korea. The several thematic maps of research area such as land cover map, topographic and soil maps, together with tabular precipitation data used for soil erosion and soil salinity calculation. Meteorological data were measured directly as air temperature, wind speed, solar radiation, and precipitation. The experiment was conducted 2% sloped lysimeter ($5.0m{\times}20.0m$) with 14 treatments and it were separated by low salinity division (LSD) and high salinity division (HSD) install. The cation content in ground water increased during time course, but in the case of land surface water the content was variable, and $K^+$ was lower than that of $Na^+$ and $Mg^{2+}$. At the LSD under rainproof condition, the salinity was directly proportional to soil water content, but at the HSD the tendency was no reversed. In condition of rainproof, the amount of soil salinity was higher at the HSD than at the LSD. Positive correlation was obtained between the soil water content and available phosphorous content at the rainfall division, but there was no significance at the surface soil of the rainproof division. Sodium adsorption ratio and anion contents in soil were repressed in the order of vinyl-mulching > non-mulching > bare field. According to the result of analyzing soil loss, soil loss occurred in a vinyl-mulching, a non-mulching and a bare field in size order, and also approximately 11.2 ton/ha soil loss happened on the reclaimed land area. The average soil loss amount by the unit area takes place in a non-mulching and bare field a lot. Our results indicate that soluble salt control and soil erosion are critical at reclaimed tidal saline soil and the results can provide some useful information for deciding management plans to reduce soil loss and salt damage for stable crop production and diverse utilization or cultivation could be one of the management options to alleviate salt damage at reclaimed tidal saline soil in Korea.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.193-199
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• 2009

A bacterium producing the halotolerant extracellular protease was isolated from squid jeotgal, and was identified as Bacillus sp. SJ-10 based on morphological, physiological and biochemical characteristics, as well as phylogenetic analysis using 16S rRNA gene sequence. The strain grew at $20^{\circ}C\sim55^{\circ}C$, pH 5~8, and 0%~14% NaCl and optimal growth conditions were $35{\pm}5^{\circ}C$, pH 7, and 5% NaCl. The major cellular fatty acids were anteiso-$C_{15:0}$, anteiso-$C_{17:0}$, and $C_{16:0}$ DNA G+C content was 50.58 mol% and menaquinone consisted of MK-7 Phylogenic analysis based on the 16S rRNA gene sequence indicated that SJ-10T belongs to the genus Bacillus. About 40 kDa of the salt-tolerant protease was purified by 40% ammonium sulfate saturation and Mono Q column chromatography. The optimal activity of the protease was pH 8 and stable at pH 5~10. The optimum temperature and NaCl concentration were $35{\pm}5^{\circ}C$ and $5{\pm}1%$, respectively.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.461-464
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• 2002

A Chemoautotroph identified as an Aeromonas sp. strain JS-1 was isolated from fresh water. Aeromonas sp. strain JS-1 used the $H_2$ and $CO_2$ as energy and carbon sources, respectively. Growth characteristics for improving the $CO_2$ fixation rate were examined in batch cultivation. Its results shown that the optimal growth appeared at culture conditions of $35^{\circ}C$, pH 7 and NaCl 0.1%(w/v). Some hydrogen-oxidizing bacteria were reported that the enzyme activity of ribulose 1,5-bisphosphate carboxylase- oxygenase (RubisCO-EC 4.1.1.39), in the key enzyme of the Calvin-Benson cycle. A RubisCO was purified from a chemoautotrophic bacterium, Aeromonas sp. strain JS-1. the enzyme was purified by ammonium sulfate precipitation, DEAE-sepharose CL-6B and gel filtration chromatography. The RubisCO showed that molecular mass was about 560KDa from gel filtration chromatography and nondenaturing PAGE, and the RubisCO was confirmed to consist of $L_8S_8$ enzyme structure by sodium dodecyl sulfate polyacrylamide gel electrophoresis. A large subunit was about 56KDa and small one was about 15kDa. The Km values of the enzyme for ribulose 1,5-bisphosphate(RUBP), $NaH^{14}CO_3$, and $Mg^{++}$ were estimated to be 0.25mM, 5.2mM, and 0.91mM, respectively. The optimum temperature for RubisCO enzymatic activity were $50^{\circ}C$, and the enzymatic activity was stable up to $45^{\circ}C$.

• KSBB Journal
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• v.23 no.1
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• pp.65-69
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• 2008

The culture broth of a ${\beta}$-glucan-producing bacterium, Paenibacillus polymyxa JB115, was confirmed to show the antibiosis against pathogenic bacteria of livestock disease. The antibacterial substance produced by P. polymyxa JB115 exhibited strong bactericidal or bacteriostatic effect on the growth of livestock pathogenic bacteria including Staphylococcus aureus, Salmonella choleraesuis, Escherichia coli and Pseudomonas aeruginosa. This antibacterial substance also showed high stabilities in broad pH range (pH 3-11) and in broad temperature range $(40-121^{\circ}C)$, which is good enough to apply spray-dry method for the formulation of culture broth. It was also found that the antibacterial substance was very stable in artificial gastric fluid and bile acid, which implies the anticipated antibacterial activity against gastrointestinal bacteria harmful for livestocks. In conclusion, the culture broth of P. polymyxa JB115 can be developed as a multifuctional feed additive containing immune-enhancing ${\beta}$-glucan as well as antibacterial agent against livestock pathogenic bacteria.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.575-581
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• 2020

A colorless antistatic agent was prepared for use in antistatic films for liquid crystal displays (LCDs) requiring low surface resistance and high transmittance. Among various lithium-fluoro compounds and quaternary ammonium salts, antistatic materials were selected based on their electrical conductivity, and antistatic agents were prepared to measure the surface resistance. As a result, the material with high conductivity showed a relatively low surface resistance, i.e., relatively good antistatic performance. Based on the antistatic materials selected, the formulation ratio for producing the best antistatic agent was established through the experimental design method and the effects of each factor were analyzed. The higher the use of lithium- fluoro compounds as antistatic materials, the higher the ratio of oligomer use with multi-functional groups, and the smaller the surface resistance. The quaternary ammonium salts increased the antistatic performance of the lithium-fluoro compounds, but the effects of the amount used were not relatively large. After manufacturing the antistatic PET film, the properties of the antistatic film showed low surface resistance values (<10⁹ Ω/sq.), high permeability (>92%), low haze (<0.5%), and high whiteness (L^⁎>95). In addition, the antistatic film reliability was found to be excellent by showing a stable surface-resistance change rate of less than 10%, even under high temperature and high humidity conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.304-311
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• 2020

The purpose of this study is to change plant growth according to the light quantity of LED light source and to standardize plant factories technology according to the optimal LED light range. Growth was relatively stable at the 1,400 lx and 1,600 lx intensities, and growth continued with increasing light intensity, but growth slowed down with growth without leaves (Ed- I don't understand). The growth characteristics at 400 lx to 800 lx were sustained to some extent during the experimental period, but the growth of the larvae was maintained until the 7th day and the growth of leaves was not developed. From 1,000 lx to 1,400 lx, brightness, leaf growth and daily growth increased, and the growth cycle exhibited a repeating cycle of growth and slowdown. In addition, 1,600 lx and 1,800 lx showed similar growth to that at 1,400 lx, but leaf growth was high. However, at 1,800 lx, the growth was slightly higher than at 1,400lx and it slowed down over time. In addition, the stronger the light, the higher the temperature around the plant and the greater the dryness of the leaves due to the heat emitted from the light source.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.15-15
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• 1999

In chip plating, several parameters must be taken into consideration. Current density, solution concentration, pH, solution temperature, components volume, chip and media ratio, barrel geometrical shape were most likely found to have an effect to the process yields. The 3 types of barrels utilized in chip plating industry are the conventional rotating barrel. vibrational barrel (vibarrel), and the centrifugal type. Conventional rotating barrel is a close type and is commonly used. The components inside the barrel are circulated by the barrel's rotation at a horizontal axis. Process yield has known to have higher thickness deviation. The vibrational barrel is an open type which offers a wide exposure to electrolyte resulting to a stable thickness deviation. It rotates in a vertical axis coupled with multi-vibration action to facilitate mixed up and easy transportation of components, The centrifugal barrel has its plated work centrifugally compacted against the cathode ring for superior electrical contact with simultaneous rotary motion. This experiment has determined the effect of barrel vibration intensity to the plating thickness distribution. The procedures carried out in the experiment involved the overall plating process., cleaning, rinse, Nickel plating, Tin-Lead plating. Plating time was adjusted to meet the required specification. All other parameters were maintained constant. Two trials were performed to confirm the consistency of the result. The thickness data of the experiment conducted showed that the average mean value obtained from higher vibrational intensity is nearer to the standard mean. The distribution curve shown has a narrower specification limits and it has a reduced variation around the target value, Generally, intensity control in vi-barrel facilitates mixed up and easy transportation of components, However, it is desirable to maintain an optimum vibration intensity to prevent solution intrusion into the chips' internal electrode. A cathodic reaction can occur in the interface of the external and internal electrode. $2HD{\;}+{\;}e{\;}{\rightarrow}20H{\;}+{\;}H_2$ Hydrogen can penetrate into the body and create pressure which can cause cracks. At high intensity, the chip's motion becomes stronger, its contact between each other is delayed and so plating action is being controlled. However, the strong impact created by its collision can damage the external electrode's structure thereby resulting to bad plating condition. 1 lot of chip was divided into two equal partion. Each portion was loaded to the same barrel one after the other. Nickel plating and tin-lead plating was performed in the same station. Portion A maintained the normal barrel vibration intensity and portion B vibration intensity was increased two steps higher. All other parameters, current, solution condition were maintained constant. Generally, plating method find procedures were carried out in a best way to maintained the best plating condition. After plating, samples were taken out from each portion. molded and polished. Plating thickness was investigated for both. To check consistency of results. 2nd trial was done now using different lot of another characteristics.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.675-688
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• 2007

To characterize organic and elemental carbon (OC and EC), and water-soluble organic carbon (WSOC) contents, daily $PM_{2.5}$ measurements were performed in August 2006 (summer) and Jan $11{\sim}Feb$ 12 2007 (winter) at an urban site of Gwangju. Daily size-segregated aerosol samples were also collected for WSOC analysis. No clear seasonal variations in EC and WSOC concentrations were observed, while seasonal differences in OC concentration, and OC/EC and WSOC/EC ratios were shown. The WSOC/OC ratio showed higher value in summer (0.56) than in winter (0.40), reflecting the greater enhancement of secondary WSOC formation at the site in summer. Secondary WSOC concentrations estimated using EC tracer method were in the range $0.0{\sim}2.1\;{\mu}g/m^3$ (average $0.42\;{\mu}g/m^3$) and $0.0{\sim}1.1\;{\mu}g/m^3\;(0.24\;{\mu}g/m^3)$, respectively, accounting for $0{\sim}51.6%$ (average 16.8%) and $0{\sim}52.5%$ (average 13.1 %) of the measured WSOC concentrations in summer and winter. Sometimes higher WSOC/OC ratio in winter than that in summer could be attributed to two reasons. One is that the stable atmospheric condition often appears in winter, and the prolonged residence time would strengthen atmospheric oxidation of volatile organic compounds. The other is that decrease of ambient temperature in winter would enhance the condensation of volatile secondary WSOC on pre-existing aerosols. In summertime, atmospheric aerosols and WSOC concentrations showed bimodal size distributions, peaking at the size ranges $0.32{\sim}0.56\;{\mu}m$ (condensation mode) and $3.2{\sim}5.6\;{\mu}m$ (coarse mode), respectively. During the wintertime, atmospheric aerosols showed a bimodal character, while WSOC concentrations showed a unimodal pattern. Size distributions of atmospheric aerosols and WSOC with a peak in the size range $0.32{\sim}0.56\;{\mu}m$ were observed for most of the measurement periods. On January 17, however, atmospheric aerosols and WOSC exhibited size distributions with modal peaks in the size range $1.0{\sim}1.8\;{\mu}m$, suggesting that the aerosol particles collected on that day could be expected to be more aged, i.e, longer residence time, than the aerosols at other sampling periods.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.120-120
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• 1998

Boron nitride (BN) films have attracted a growing interest for a variety of t technological applications due to their excellent characteristics, namely hardness, c chemical inertness, and dielectrical behavior, etc. There are two crystalline phases 1551; of BN that are analogous to phases of carbon. Hexagonal boron nitride (h-BN) has a a layered s$\sigma$ucture which is spz-bonded structure similar to that of graphite, and is t the stable ordered phase at ambient conditions. Cubic boron nitride (c-BN) has a z zinc blende structure with sp3-bonding like as diamond, 따ld is the metastable phase a at ambient conditions. Among of their prototypes, especially 삼Ie c-BN is an i interesting material because it has almost the same hardness and thermal c conductivity as di없nond. C Conventionally, significant progress has been made in the experimental t techniques for synthesizing BN films using various of the physical vapor deposition 밍ld chemical vapor deposition. But, the major disadvantage of c-BN films is that t they are much more difficult to synthesize than h-BN films due to its narrow s stability phase region, high compression stress, and problem of nitrogen source c control. Recent studies of the metalorganic chemical vapor deposition (MOCVD) of I III - V compound have established that a molecular level understanding of the d deposition process is mandatory in controlling the selectivity parameters. This led t to the concept of using a single source organometallic precursor, having the c constituent elements in stoichiometric ratio, for MOCVD growth of 삼Ie required b binary compound. I In this study, therefore, we have been carried out the growth of h-BN thin f films on silicon substrates using a single source precursors. Polycrystalline h-BN t thin films were deposited on silicon in the temperature range of $\alpha$)() - 900 $^{\circ}$C from t the organometallic precursors of Boron-Triethylamine complex, (CZHs)3N:BRJ, and T Tris(dimethylamino)Borane, [CH3}zNhB, by supersonic molecular jet and remote p plasma assisted MOCVD. Hydrogen was used as carrier gas, and additional nitrogen w was supplied by either aDlIDonia through a nozzle, or nitrogen via a remote plasma. T The as-grown films were characterized by Fourier transform infrared spectroscopy, x x-ray pthotoelectron spectroscopy, Auger electron spectroscopy, x-ray diffraction, t transmission electron diffraction, optical transmission, and atomic force microscopy.roscopy.