• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.801-809
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• 2014

This study was conducted to compare an experimental extruded pellet (EP) and raw fish-based moist pellet (MP) on growth performance, whole-body and dorsal muscle composition, and textural properties of dorsal muscle for olive flounder Paralichthys olivaceus. Four groups of 8,000 fish (initial mean weight $27.1{\pm}0.05g$) per concrete tank ($10{\times}10m$) were fed the experimental diets for 16 months. After the feeding trial, no significant differences were observed in final mean body weight, weight gain, specific growth rate, feed intake, survival, and condition factor between EP and MP groups. However, feed efficiency of fish fed the EP was significantly higher than that of fish fed the MP. Moisture content in the whole-body of fish fed the MP was significantly higher than that of fish fed the EP. Significantly higher contents of polyunsaturated fatty acid (PUFA) in whole-body and dorsal muscle were observed in fish fed the EP compared with fish fed the MP. Any notable differences in amino acid contents or textural properties of the dorsal muscle were not observed in fish fed either the EP or the MP. The results of this study indicated that the EP could be developed to replace MP for the market size of production in olive flounder without the adverse effects on growth performance. Formulation of the EP could be used as a practical feed for olive flounder.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.49-62
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• 2011

Objectives : This study was designed to examine the effects of Polygonatum odoratum EtOH ext. on lowering lipid and anti-oxidation using hyperlipidemic rat. Methods : Male rats weighting $195.21{\pm}4.93g$ were divided into 4 groups and fed high fat diet for 8 weeks. Each of 7 rats was divided into a control and sample group. We fed a control group of rats a basal diet and administered normal saline(100 mg/kg, 1 time/1 day) for 4 weeks. And we fed each experimental group of rats basal diet and administered an extract of Polygonatum odoratum(100 mg/kg, 200 mg/kg, 300 mg/kg, 1 time/1 day) for 4 weeks. At the end of the experiment, the rats were sacrificed to determine their chemical composition. We measured lipid of plasma and liver, concentration of anti-oxidative activity and tumor necrosis factor-$\alpha$($TNF-{\alpha}$). Results : 1. Concentration of plasma free fatty acid, low density lipoprotein-cholesterol showed a significant decrement in the 200 mg/kg and 300 mg/kg Polygonatum odoratum EtOH ext. groups than that of control group. Concentration of plasma total cholesterol, triglyceride showed a significant decrement in all Polygonatum odoratum EtOH ext. groups than that of control group. However, concentration of plasma high density lipoprotein-cholesterol was not significantly different in all the treatment groups. 2. Concentration of liver total cholesterol showed a significant decrement in the 200 mg/kg and 300 mg/kg Polygonatum odoratum EtOH ext. groups than that of control group. Concentration of liver triglyceride(TG) showed a significant decrement in all Polygonatum odoratum EtOH ext. groups than that of control group. 3. Concentration of plasma thiobarbituric acid reactive substance, and liver thiobarbituric acid reactive substance showed a significant decrement in the 200 mg/kg and 300 mg/kg Polygonatum odoratum EtOH ext. groups than that of control group. 4. The values of glutathione peroxidase activity showed a significant increment in all Polygonatum odoratum EtOH ext. groups than that of control group. The values of superoxide dismutase activity and catalase activity showed a significant increment in the 200 mg/kg and 300 mg/kg Polygonatum odoratum EtOH ext. groups than that of control group. 5. The values of plasma aspartate aminotransferase and alanine aminotransferase activities were not significantly different in all treatment groups. 6. Concentration of liver $TNF-{\alpha}$ showed a significant decrement in the 200 mg/kg and 300 mg/kg Polygonatum odoratum EtOH ext. groups than that of control group. Conclusions : Based on the results in this study, the Polygonatum odoratum EtOH ext. showed a positive effect in lowering lipid and anti-oxidation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.489-493
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• 2016

In this study, the effect of vanadium oxide ($V_2O_5$) content and pre-sintering atmosphere on sealing property of glass frit that consisted of $V_2O_5-BaO-ZnO-P_2O_5-TeO_2-CuO-Fe_2O_3-SeO_2$ was investigated by XPS (X-ray photoelectron spectroscopy). The content of V2O5 was changed to 15, 30, and 45 mol%, and the pre-sintering was carried out in air and $N_2$ condition, respectively. XPS analysis conducted before and after laser irradiation with identical sample. Before laser treatment, glass frits that were pre-sintered at air condition showed both $V^{4+}$ and $V^{5+}$, but the valence state was changed to $V^{5+}$ after laser irradiation when the glass frits contained 30 and 45 mol% $V_2O_5$; this change led to non-adhesive property. On the other hand, glass frits that were pre-sintered at $N_2$ condition exhibited only $V^{4+}$ and it showed fine adhesion irrespective of the $V_2O_5$ content. As a result, the existence of $V^{4+}$ seems to be a major factor for controlling the adhesive property of glass frit for laser sealing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.217-222
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• 2010

Two 15-week feeding trials were conducted to investigate how the rate and frequency of feeding affected the winter growth of olive flounder ($13^{\circ}C$). In the first experiment, triplicate groups of fish (initial mean weight $117{\pm}6.0$ g) were fed extruded pellets twice a day at feeding rates of 0.1, 0.25, 0.4, 0.55, and 0.57% (satiation) body weight per day (BW/d). The weight gain, specific growth rate, and feed efficiency increased significantly (P<0.05) with the feeding rates from 0.1 to 0.55% BW/d, but no significant differences in these parameters were found for fish fed diets of 0.55% BW/d and satiation. The moisture and ash contents of whole body of fish tended to decrease as the feeding rate increased, but the opposite trend was found for crude lipid content. In the second experiment, triplicate groups of fish (initial mean weight $117{\pm}6.3$ g) were fed extruded pellets to apparent satiation at the three different feeding frequencies: one meal 2 days, one meal a day and two meals a day. The weight gain and specific growth rate of fish fed one meal 2 days were significantly (P<0.05) lower than those of fish fed one or two meals a day, whereas no significant differences in the weight gain and specific growth rate were found between fish fed one and those fed two meals a day. Feed efficiency and condition factor were not significantly affected by feeding frequency. Based on these results, a feeding rate of 0.3% BW/d is recommended as maintenance feeding level, and the optimum feeding frequency is one meal a day with satiation feeding for the growth of olive flounder (117-147 g) during winter ($13^{\circ}C$).

• Macromolecular Research
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• v.11 no.4
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• pp.207-223
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• 2003

For last five years, we are developing the novel local drug delivery devices using biodegradable polymers, especially polylactide (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) due to its relatively good biocompatibility, easily controlled biodegradability, good processability and only FDA approved synthetic degradable polymers. The relationship between various kinds of drug [water soluble small molecule drugs: gentamicin sulfate (GS), fentanyl citrate (FC), BCNU, azidothymidine (AZT), pamidronate (ADP), $1,25(OH)_2$ vitamin $D_3$, water insoluble small molecule drugs: fentanyl, ipriflavone (IP) and nifedipine, and water soluble large peptide molecule drug: nerve growth factor (NGF), and Japanese encephalitis virus (JEV)], different types of geometrical devices [microspheres (MSs), microcapsule, nanoparticle, wafers, pellet, beads, multiple-layered beads, implants, fiber, scaffolds, and films], and pharmacological activity are proposed and discussed for the application of pharmaceutics and tissue engineering. Also, local drug delivery devices proposed in this work are introduced in view of preparation method, drug release behavior, biocompatibility, pharmacological effect, and animal studies. In conclusion, we can control the drug release profiles varying with the preparation, formulation and geometrical parameters. Moreover, any types of drug were successfully applicable to achieve linear sustained release from short period ($1{\sim}3$ days) to long period (over 2 months). It is very important to design a suitable formulation for the wanting period of bioactive molecules loaded in biodegradable polymers for the local delivery of drug. The drug release is affected by many factors such as hydrophilicity of drug, electric charge of drug, drug loading amount, polymer molecular weight, the monomer composition, the size of implants, the applied fabrication techniques, and so on. It is well known that the commercialization of new drug needs a lot of cost of money (average: over 10 million US dollar per one drug) and time (average: above 9 years) whereas the development of DDS and high effective generic drug might be need relatively low investment with a short time period. Also, one core technology of DDS can be applicable to many drugs for the market needs. From these reasons, the DDS research on potent generic drugs might be suitable for less risk and high return.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.65-65
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• 2012

Copper zinc tin sulfide ($Cu_2ZnSnS_4$, CZTS) is a very promising material as a low cost absorber alternative to other chalcopyrite-type semiconductors based on Ga or In because of the abundant and economical elements. In addition, CZTS has a band-gap energy of 1.4~1.5eV and large absorption coefficient over ${\sim}10^4cm^{-1}$, which is similar to those of $Cu(In,Ga)Se_2$(CIGS) regarded as one of the most successful absorber materials for high efficient solar cell. Most previous works on the fabrication of CZTS thin films were based on the vacuum deposition such as thermal evaporation and RF magnetron sputtering. Although the vacuum deposition has been widely adopted, it is quite expensive and complicated. In this regard, the solution processes such as sol-gel method, nanocrystal dispersion and hybrid slurry method have been developed for easy and cost-effective fabrication of CZTS film. Among these methods, the hybrid slurry method is favorable to make high crystalline and dense absorber layer. However, this method has the demerit using the toxic and explosive hydrazine solvent, which has severe limitation for common use. With these considerations, it is highly desirable to develop a robust, easily scalable and relatively safe solution-based process for the fabrication of a high quality CZTS absorber layer. Here, we demonstrate the fabrication of a high quality CZTS absorber layer with a thickness of 1.5~2.0 ${\mu}m$ and micrometer-scaled grains using two different non-vacuum approaches. The first solution-processing approach includes air-stable non-toxic solvent-based inks in which the commercially available precursor nanoparticles are dispersed in ethanol. Our readily achievable air-stable precursor ink, without the involvement of complex particle synthesis, high toxic solvents, or organic additives, facilitates a convenient method to fabricate a high quality CZTS absorber layer with uniform surface composition and across the film depth when annealed at $530^{\circ}C$. The conversion efficiency and fill factor for the non-toxic ink based solar cells are 5.14% and 52.8%, respectively. The other method is based on the nanocrystal dispersions that are a key ingredient in the deposition of thermally annealed absorber layers. We report a facile synthetic method to produce phase-pure CZTS nanocrystals capped with less toxic and more easily removable ligands. The resulting CZTS nanoparticle dispersion enables us to fabricate uniform, crack-free absorber layer onto Mo-coated soda-lime glass at $500^{\circ}C$, which exhibits a robust and reproducible photovoltaic response. Our simple and less-toxic approach for the fabrication of CZTS layer, reported here, will be the first step in realizing the low-cost solution-processed CZTS solar cell with high efficiency.

• Mycobiology
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• v.46 no.3
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• pp.224-235
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• 2018

Temperature is an important environmental factor that can greatly influence the cultivation of Auricularia cornea. In this study, lignin peroxidase, laccase, manganese peroxidase, and cellulose in A. cornea fruiting bodies were tested under five different temperatures ($20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$, and $40^{\circ}C$) in three different culture periods (10 days, 20 days and 30 days). In addition, the V4 region of bacterial 16S rRNA genes in the substrate of A. cornea cultivated for 30 days at different temperatures were sequenced using next-generation sequencing technology to explore the structure and diversity of bacterial communities in the substrate. Temperature and culture days had a significant effect on the activities of the four enzymes, and changes in activity were not synchronized with changes in temperature and culture days. Overall, we obtained 487,694 sequences from 15 samples and assigned them to 16 bacterial phyla. Bacterial community composition and structure in the substrate changed when the temperature was above $35^{\circ}C$. The relative abundances of some bacteria were significantly affected by temperature. A total of 35 genera at five temperatures in the substrate were correlated, and 41 functional pathways were predicted in the study. Bacterial genes associated with the membrane transport pathway had the highest average abundance (16.16%), and this increased at $35^{\circ}C$ and $40^{\circ}C$. Generally, different temperatures had impacts on the physiological activity of A. cornea and the bacterial community in the substrate; therefore, the data presented herein should facilitate cultivation of A. cornea.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.110-119
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• 2015

The construction of the eight large weirs in the Nakdong River, the second largest river in Korea, caused big changes in the physical environment of the water system. Algal communities and their correlations with environmental factors, mainly nutrients were studied at five weir areas in the Nakdong River from 2010 to 2013. Water quality, hydrodynamics and algal composition were investigated. Results showed that flow velocities were reduced compared with that before weir construction near the areas where are located in the mid and upstreams of the Nakdong River. A seasonal algal community succession was observed and it was mainly correlated with temperature and phosphorus. Diatoms were dominated from winter to spring months and massive diatomic blooms of Stephanodiscus sp. occurred early in March during survey period. Cyanobacterial blooms of Microcystis sp. occurred from July to September 2013 and was preceded by the lower total phosphorus concentration of $0.05mg\;L^{-1}$. The correlations between total phosphorus concentrations and algal abundances were not significant during the survey periods. However, significant correlation with cyanobacteria was found in the period of weir construction after only at the GG survey site and blooms periods of 7 times in the survey sites, and its correlation coefficients were 0.53 (p<0.001) and 0.42 (p<0.01) respectively. When algal bloom was observed, partially low nutrient concentration was observed in the Nakdong River. In conclusion, partially low nutrient concentration which may result from algal bloom was observed, and we presume it caused the reduction of algal abundunces.

• Current Photovoltaic Research
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• v.1 no.1
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• pp.38-43
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• 2013

$Cu(In,Ga)_3Se_5$ is a candidate material for the top cell of $Cu(In,Ga)Se_2$ tandem cells. This phase is often found at the surface of the $Cu(In,Ga)Se_2$ film during $Cu(In,Ga)Se_2$ cell fabrication, and plays a positive role in $Cu(In,Ga)Se_2$ cell performance. However, the exact properties of the $Cu(In,Ga)_3Se_5$ film have not been extensively studied yet. In this work, $Cu(In,Ga)_3Se_5$ films were fabricated on Mo-coated soda-lime glass substrates by a three-stage co-evaporation process. The Cu content in the film was controlled by varying the deposition time of each stage. X-ray diffraction and Raman spectroscopy analyses showed that, even though the stoichiometric Cu/(In+Ga) ratio is 0.25, $Cu(In,Ga)_3Se_5$ is easily formed in a wide range of Cu content as long as the Cu/(In+Ga) ratio is held below 0.5. The optical band gap of $Cu_{0.3}(In_{0.65}Ga_{0.35})_3Se_5$ composition was found to be 1.35eV. As the Cu/(In+Ga) ratio was decreased further below 0.5, the grain size became smaller and the band gap increased. Unlike the $Cu(In,Ga)Se_2$ solar cell, an external supply of Na with $Na_2S$ deposition further increased the cell efficiency of the $Cu(In,Ga)_3Se_5$ solar cell, indicating that more Na is necessary, in addition to the Na supply from the soda lime glass, to suppress deep level defects in the $Cu(In,Ga)_3Se_5$ film. The cell efficiency of $CdS/Cu(In,Ga)_3Se_5$ was improved from 8.8 to 11.2% by incorporating Na with $Na_2S$ deposition on the CIGS film. The fill factor was significantly improved by the Na incorporation, due to a decrease of deep-level defects.

• Journal of Conservation Science
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• v.32 no.4
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• pp.549-560
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• 2016

The purpose of this study is to identify the material characteristics of blackwares excavated from the Bonggok kiln site in Jinan-gun, Jeollabuk-do Province, South Korea, by scientific analyses and a reproduction experiment. Scientific analyses were conducted to determine the physical properties, chemical composition and for microscopic observation of blackwares. A reproduction experiment was also conducted by producing ceramic samples with black glaze, red ocher and limestone, and then cross sections of the samples were observed. The analysis results showed that all the excavated blackwares have similar properties such as chromaticity, specific gravity, absorption factor and porosity, but there is a difference depending on the crystallization of the ceramics. Thermal analysis showed that the exothermic peak was observed at about $1200^{\circ}C$, and crystal structure analysis indicated the presence of mullite. Hence, it can be concluded that the firing temperature of the excavated blackwares was around $1100-1200^{\circ}C$. Moreover, the glaze present on these blackwares has about 22% higher $Fe_2O_3$ content than those excavated from other places; however, the former has lower CaO content. For the reproduction experiment, samples were made using limestone as a flux and red ocher as a glaze. The results show that the cross section of the glaze layer of the reproduced sample have iron crystals with dendritic structures, similar to those present in the excavated black-wares. It is assumed that such iron crystals were formed during the process of melting and solidification of the iron oxide present in the blackwares.