• Applied Biological Chemistry
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• v.41 no.1
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• pp.47-52
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• 1998

3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes the conversion of HMG-CoA to mevalonic acid, the first intermediate of isoprenoid biosynthetic pathway in plants. The enzyme was solubilized with 0.4% Brij (polyoxyethylene ether) W-1 from a microsomal fraction of etiolated rice seedlings (Oryza sativa L.) in which its maximal activity was observed on the fourth day after germination. HMGR was purified to near homogeneity by employing $(NH_4)_2SO_4$ fractionation plus chromatographic procedures including DEAE-Sephadex A-50 and HMG-CoA-hexane-agarose affinity column. The size of the purified enzyme was estimated to be 55 kDa when judged by SDS-PAGE analysis with silver staining method. The apparent $K_m$ and $V_{max}$ values for HMG-CoA were determined to be $180\;{\mu}M$ and 107 pmol/min/mg, and those for NADPH were $810\;{\mu}M$ and 32.1 pmol/min/mg, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6610-6617
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• 2013

This study examined the current and future Indoor Air Quality (IAQ) control device markets and analyzed the recent studies on indoor air pollutantr emoval to develop a new technology for fine dust control. Currently, the mechanical filter technique occupies the bulk of the IAQ control market but the electronic technique is emerging as an alternative to control fine dust efficiently. Among the gaseous VOCs and fine dust particles contaminating the indoor air quality, fine dust particles are more problematic because they threaten human health by penetrating deep into the body and producing secondary contaminants by chemical reaction with VOCs. The electronic IAQ control device using dielectrophoretic and electrostatic forces is a good option for public spaces where many people pass, and at the same time, it needs to consider temperature, humidity, and the particle properties of specific areas to highlight the control efficiency. Electronic-related technology is expected to be used widely in many public/private spaces wherever a dust-free environment is required.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.261-271
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• 2007

Phytoremediation is an economic and environmentally friendly technique to remediate contaminated-soil. In this study, the effects of plants, rhizobacteria and physicochemical factors on phytoremediation have been reviewed. For successful phytoremediation, the selection of plants is primarily important. To remediate soil contaminated with petroleum hydrocarbon, raygrass (Lolium multiflorum lam), white mustard, vetch (Vicia villosa), tall fescue (Festuca arundinacea), legumes, poplar, and Pine (Pinus densiflora) were mainly applied, and the removal efficiency of petroleum hydrocarbon were ranged 68 to 99%. Corn (Zea mays), raygrass (Lolium multiflorum lam), vetch (Vicia villosa), mustard, clover (Trifolium repens), and tall fescue (Festuca arundinacea) were used for the removal of polycyclic aromatic hydrocarbon, and their removal efficiencies were 50-98%. Rhizobacteria play significant roles for phytoremediation because they can directly participate in the degradation of contaminant as well as promoting plants growth. The following rhizobacteria were preferred for phytoremediation: Azospirillum lipoferum, Enterobactor cloacae, Azospirillum brasilense, Pseudomonas putida, Burkholderia xenovorans, Comamonas testosterone, Pseudomonas gladioli, Azotobacter chroococcum, Bacillus megaterium, and Bacillus subtilis. Pysicochemical factors such as pH, temperature, nutrient, electron acceptor, water content, organic content, type of contaminants are consequential limiting factors for phytoremediation.

• Environmental Analysis Health and Toxicology
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• v.6 no.1_2
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• pp.71-82
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• 1991

Rat embryos were cultured out of the mother from the head-fold stages, 9.5 days to 11.5 days during which they start to develop the brain, eyes, ears and cardiovascular system etc. We principally did the basic experiment in order to establish the best condition of the rat whole embryo culture in our laboratory. The temperature in the culture system was maintained 37$^{\circ}C$$\pm$0.2$^{\circ}C$ for 48 hrs. The culture was carried out in humidified atmosphere of the air, intially, the bottles were equilibrated with 5% $O_2$,5% $CO_2$, and 90% $N_2$gas mixture. After 22 or 24 and 29 or 30 hrs the cultures were reequilibrated with 20% $O_2$, 5% $CO_2$,75% $N_2$and 40% $O_2$, 5% $CO_2$, 55%$N_2$respectively. Various types of sera were tested and for the purpose of minimizing the quantity of rat serum, artificial medium was also tried and it was determined that rat serum supported normal growth over a period of 48 hrs, based on total growth analysis and structural comparisons with in vivo specimens.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.530-537
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• 2014

Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at $25^{\circ}C$. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability.

• Journal of the Korean Vacuum Society
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• v.21 no.5
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• pp.233-241
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• 2012

We have deposited the bilayer consisted of the underlayer and the overlayer by using DC magnetron sputter on Single crystal MgO (001) substrate. This bilayer was fabricated at fixed annealing temperature and time. We have controlled agglomeration effect by changing of the bilayer thickness. Finally, we have made the self-organization and nano-structured film. In this processing, we have made nano-dot which consists of the underlayer and the overlayer, unlike the existing method called the agglomeration effect in the single layer. The underlayer has deposited using Ti, Cr and Co. And the overlayer has deposited with Ag. Through the analysis of Atomic force microscopy (AFM), the microstructure of underlayer is observed by AFM to confirm the formation of nano-dot. As the nano-dot through above processing, we have found that the nano-dot has the different shape. As a result, when we manufactured nano-dot through the agglomeration effect of bi-layer, the best matching material is Ti for underlayer. And also, we have found that MgO/Ti/Ag samples have been grown expitaxially toward the direction of MgO (001) by X-ray Diffraction analysis.

• Journal of Korea Water Resources Association
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• v.47 no.8
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• pp.671-684
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• 2014

Change point analysis is a efficient tool to understand the fundamental information in hydro-meteorological data such as rainfall, discharge, temperature etc. Especially, this fundamental information to change points to future rainfall data identified by reasonable detection skills can affect the prediction of flood and drought occurrence because well detected change points provide a key to resolve the non-stationary or inhomogeneous problem by climate change. Therefore, in this study, the comparative study to assess the performance of the 3 change point detection skills, cumulative sum (CUSUM) method, Bayesian change point (BCP) method, and segmentation by dynamic programming (DP) was performed. After assessment of the performance of the proposed detection skills using the 3 types of the synthetic series, the 2 reasonable detection skills were applied to the observed and future rainfall data at the 5 rainfall gauges in South Korea. Finally, it was suggested that BCP (with 0.9 posterior probability) could be best detection skill and DP could be reasonably recommended through the comparative study. Also it was suggested that BCP (with 0.9 posterior probability) and DP detection skills to find some change points could be reasonable at the North-eastern part in South Korea. In future, the results in this study can be efficiently used to resolve the non-stationary problems in hydrological modeling considering inhomogeneity or nonstationarity.

• The Journal of the Petrological Society of Korea
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• v.16 no.3
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• pp.180-188
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• 2007

We carried on CHIME zircon age dating for the Gamaksan alkaline meta-granitoid (GAM) from the northwestern margin of the Gyeonggi massif, and obtained a timing of regional metamorphism at $247{\pm}14Ma$ (n=103, MSWD=0.92). The age is compatible with Permo-Triassic regional metamorphic ages from the Imjingang Belt which has been regarded as possible eastward extension of Triassic collisional belt in China. Considering an extensional ductile shearing of the Gyeonggi (Kyonggi) Shear Zone which deformed GAM occurred at 226 Ma with temperature condition about $500^{\circ}C$ (Kim et al., 2000), and the Late Triassic to Early Jurassic Daedong Group unconformably overlies on top of the ductile shear zone, cooling rate of GAM over the period can be estimated as $18{\sim}10^{\circ}C/Ma$. Since new zircon begin to pow at temperature higher than upper-amphibolite facies condition (${\sim}700^{\circ}C$), cooling rate of GAM from peak metamorphism (247 Ma) to deposition of the Daedong G.oup (${\sim}$Early Jurassic) would be higher than $10^{\circ}C/Ma$. Such rapid cooling rate is compatible with that reported from exhumation stage of the Dabie-Sulu Belt, and supports an idea that the Gyeonngi massif is a part of Permo-Triassic orogenic belt in East Asia.

• Food Science and Preservation
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• v.13 no.3
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• pp.304-309
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• 2006

In order to examine the antimicrobial effect on dairy processing facilities and products, Prunus mume extinct (PME) was applied to the pilot plant system of dairy industry and yogurt, PME showed thermal and pH stability in the wide spectrum of temperature ($40{\sim}150^{\circ}C$) and pH ($4{\sim}10$) and remarkable antimicrobial activities against dairy spoilage microorganisms. As the result of aseptic treatment of dairy processing facilities with PME microbial colony including coliform bacteria was not detected canpore to those detected in the control. In the level of PME concentration which inhibit the growth of putrefactive microorganisms we could produce yogurt with good scores of sensory evaluation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.780-787
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• 2019

As a carbon-free, green growth alternative, internal and external interest in hydrogen energy and technology is growing. Hydrogen was added to co-axial methane, methane-propane, and methane-propane-ethane diffusion flames, which are the main ingredients of LNG, to evaluate its effect on flame formation and combustion products. The variation in combustion products produced by adding hydrogen gradually to diffusion pyrolysis at room temperature and normal pressure conditions was observed experimentally by using a gas analyzer, and the shape of diffusion pyrolysis was observed step by step using a digital camera. The experimental results showed that the production volume of nitrogen oxides tended to increase and became close to linear as hydrogen was added to the diffusion pyrotechnic. This is because the relatively high temperature of heat insulation and fast combustion speed of hydrogen facilitated the production of thermal NOx. On the other hand, CO2 production tended to decrease as hydrogen was added to reduce the overall carbon ratio contained in the mixed diffusion flame of methane, methane-propane, and methane-ethane-propane. This means that the mixed fuel use of LNG-hydrogen in ships may potentially reduce emissions of CO2, a greenhouse gas.