• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.116-123
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• 2004

This study was conducted to investigate the changes in physicochemical and microbiological properties during fermenting process of organic fertilizer which was made from the mixture of organic materials such as sesame oil cake, fish meal, blood meal, rice bran, ground bone meal, and natural minerals such as illite, crusted oyster shell and loess. They were mixed and fermented for 70 days. The sesame oil cake and rice bran, major ingredients for organic fertilizers, consisted of 7.6 and 2.6% total nitrogen, 3.6 and 4.6% $P_2O_5$, 1.4 and 2.2% $K_2O$, respectively. The ground bone meal included 29.2% $P_2O_5$ and illite included 3.8% $K_2O$. Temperature of organic fertilizer during the fermentation rapidly increased over $50^{\circ}C$ within 2 days after mixing and stabilized similar to outdoor temperature after 40 days. Moisture content decreased from 36.3 to 16.0% after 1 month. C/N ratio of organic fertilizer slightly increased until 30 days and thereafter, it slowly decreased, It resulted from the faster decrease of total nitrogen concentration compared with organic matter. Concentration of $NH_4-N$ in organic fertilizer rapidly increased from 1,504 to $5,530mg\;kg^{-1}$, the highest concentration after 10 days. Meantime, $NO_3-N$ concentration was low and constant about $150mg\;kg^{-1}$ over the whole fermenting period. This result seemed to be due to the high pH. The organic ferfilizer fermented for 70 days was composed of 2.7% N, 2.8% $P_2O_5$, 1.8% $K_2O$, and 35.9% organic matter. Total populations of aerobic bacteria, Bacillus sp. and actinomycetes, after fermenting process, were $12.5{\times}10^{10}$, $45.5{\times}10^{5}$ and $13.6{\times}10^{5}cfu\;g^{-1}$ respectively. Pseudomonas sp. was $71.9{\times}10^{7}cfu\;g^{-1}$ at first, but it rapidly decreased according to the rise of temperature. Yeasts played an important role in the early stage of fermentation and molds did in the late stage.

• Korean journal of applied entomology
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• v.52 no.2
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• pp.115-123
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• 2013

A microbial insecticide "Bt-Plus" has been developed to enhance an insecticidal efficacy of an entomopathogenic bacterium, Bacillus thuringiensis (Bt). However, its wettable powder formulation is not preferred by farmers and industry producers due to relatively high cost. This study aimed to develop a soluble concentrate formulation of Bt-Plus. To this end, an optimal mixture ratio of two bacterial culture broths was determined to be 5:4 (v/v) of Bt and Xenorhabdus nematophila (Xn) along with 10% ethanol preservative. In addition, Bt broth was concentrated by 10 times to apply the mixture at 1,000 times fold dilution. The resulting liquid formulation was sprayed on cabbage crop field infested by late instar larvae of the diamondback moth, Plutella xylostella. The field assay showed about 77% control efficacy at 7 days after treatment, which was comparable to those of current commercial biopesticides targeting P. xylostella. For storage test in both low and room temperatures, the liquid formation showed a relatively stable control efficacy at least for a month. To develop a quality control technique to exhibit a stable control efficacy of Bt-Plus, Bt spore density ($5{\times}10^{11}$ spores/mL) and eight active component concentrations of Xn bacterial metabolites in the formulation products have been proposed in this study.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.345-350
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• 2014

The aim of this study was to investigate the effect of high temperature on the viability of probiotic organisms (Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae) mixed with animal feed under controlled conditions by simulating a farm feed bin in the summer. Following inoculation of probiotics into the feed, the pH and probiotic viability were monitored during an 8-day incubation at room temperature. Sterile and non-sterile feeds displayed different patterns of pH changes, with increased pH in non-sterile feed at 2 days, but a pattern of decreasing pH at 4 days. The viabilities of S. cerevisiae and B. subtilis after mono/co-inoculation were maintained without substantial changes during the incubation, whereas L. plantarum viability tended to decline. In both non-sterile and sterile feeds, the probiotics were maintained or grew without any antagonistic effects. Probiotic viability was also tested upon a shift to high temperature ($60^{\circ}C$). There was no distinct change in pH between sterile and non-sterile feeds after the temperature shift. L. plantarum and S. cerevisiae could not survive at the high temperature, whereas B. subtilis displayed normal growth, and it inhibited the growth of contaminant microbes. Fungal growth was not observed in non-sterile feed 2 days after supplementation with B. subtilis. Therefore, heat resistant B. subtilis could be safely used in feed bins to inhibit microbial contamination, even at high temperatures. The prevention of elevated temperature in feed bins is necessary for the utilization of L. plantarum and S. cerevisiae during the summer season.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.4
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• pp.326-335
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• 1988

In order to increase the availability of filefish scrap, the ordinary and low salt sauce were prepared, and identified their taste compounds in their products. To process the filefish scrap sauce, chopped filefish scrap was mixed with koji, 25% brine, slat and glucose (25.0 : 65.0 : 12.5 : 7.0, w/w) and fermented at $25{\pm}4^{\circ}C$ for 120 days. The same process was also carried out to process the low salt sauce adding sorbitol, lactic acid and ethyl alcohol (7.0 : 0.7 : 9.0. w/w) instead of salt. While amino nitrogen and volatile basic nitrogen(VBN) of products were decreased, pH and reducing sugar were increased all alone the fermentation period. The major free amino acids of products at final stage of fermentation were glutamic acid, alanine, leucine, lysine and aspartic acid. And the contents of total amino acid in the ordinary and low salt sauce were 4126.6(mg/100m1 sauce), 4519.5(mg/100m1 sauce) after fermentation. Hypoxanthine was revealed as the major constituent among nucleotides and their related compounds through fermentation. Free amino acid-N in the filefish scrap sauces were from 56.3%(ordinary) to 60.7%(low salted) of extractive nitrogen. From the sensory evaluation, the quality of products from filefish scrap sauce were almost equal to sold soy sauce on the market.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.316-324
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• 1985

Vacuum-packed and seasoned smoked-dried products of red squid, Ommastrephes bartrami, caught in the Northern Pacific Ocean, were prepared and stored at room temperature for 90 days to test their keeping quality. Defrosted squids were eviscerated, skinned, and cut. The mantle meats were flavored with seasoning powders prepared from sugar, sorbitol, salt, monosodium glutamate, or smoke flavor (Smoke-EZ, Alpha Foods Co., Ltd.). After seasoning, the mantle meats were dried at $45^{\circ}C$ for 7 hours, vacuum packed in plastic film bags, and pasteurized in water at $95^{\circ}C$ for 30 minutes. Three kinds of products were prepared : control products (seasoned-dried), solid smoked seasoned-dried and liquid smoked seasoned-dried. The moisture level, water activity, color value (L, a and b value), texture, and viable cell counts of bacteria in these products were determined during storage at room temperature, $5^{\circ}C\;and\;35^{\circ}C$, respectively. The results showed that the products could be preserved at good condition for 90 days though they developed pale brown color during storage. The contents of free amino acids, nucleotides and their related compounds, and the compositions of fatty acids of raw squid and smoked products were analysed. In the amino acids, arginine, taurine, glycine and proline were abundant in raw and smoked products. The contents of hypoxanthine of raw and smoked products were higher than the other nucleotides and their related compounds. In fatty acid compositions of raw and smoked products, the dominant fatty acids were docosahexaenoic acid (22:6), hexadecanoic acid(16:0) and eicosapentaenoic acid (22:5).

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.166-172
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• 2001

In order to increase ginsenoside content, to reduce chemical change, to shorten extracting procedure, new methods of extraction and fractionation of crude ginseng saponin were established and compared for their chemical composition. Those are hot MeOH extraction/n-BuOH fractionation (BuOH method) and hot MeOH extraction/Diaion HP-20 adsorption/MeOH elution (HP-20 method), which are already known methods, and additional three new methods: hot MeOH extraction/cation AG 50W $adsorption/H_2O$ elution/n-BuOH extraction (AG 50W method), cool MeOH extraction/Diaion HP-20 adsorption/MeOH elution (cool extraction method) and direct extraction with EtOAc/n-BuOH (direct extraction method). AG 50W method provided a crude saponin showing the highest content of ginsenosides of 61.5% and the lowest contents of protein and free amino acids of 0.93% and 0.19%, respectively. The protein content was the highest as 14.18% in the crude saponin by HP-20 method, while free sugar content was the highest as 13.5% by BuOH method, indicating that these are factors that lower the rate of ginsenoside in crude saponins by those methods. On the other hand, it was revealed that AG 50W method produced large amount of prosapogenins during the pass through the cation exchange resin (AG 50W) column being strongly acidic. Crude saponin from direct extraction method showed relatively higher composition of ginsenoside $Rg_1$ and Re. The results suggest that contents and composition of ginsenosides and other chemical components in crude ginseng saponin greatly depend on the condition of the extraction and fractionation.

• Journal of Mushroom
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• v.17 no.3
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• pp.113-118
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• 2019

Oyster mushrooms are an economically important crop, accounting for 35% of the total mushroom production in Korea. In this study, we developed a new cultivar of Pleurotus ostreatus, known as 'Baekseon,' which is characterized by a white pileus with a white stipe. It was bred by mating monokaryons isolated from white mutant oyster mushrooms that were naturally generated from 'Gonji-7ho' and 'Wonhyeong-1ho' at the Mushroom Research Institute, GARES, Korea in 2018. The optimum temperature for mycelial growth on potato dextrose agar medium was approximately $28-31^{\circ}C$, and the optimum temperatures for primordia formation and growth of fruit bodies on sawdust media were $22^{\circ}C$ and $20^{\circ}C$, respectively. The time required for the bottle-cultured mushrooms to complete spawn running, primordia formation, and growth of fruit bodies was 30 days, 4 days, and 4 days, respectively. The fruit bodies were bundle-shaped, the pilei were round type and white, and the stipes were white. The stipes were slender and longer than those of the control ('Miso'). In the productivity test, the yield per bottle was 185 g/1100 mL, which was 45% greater than that of the control ('Miso'). In the farm test, the yield per bottle for Farm A (Pyeongtaek) and Farm B (Yeoju) was 184 g/1100 mL and 178 g/850 mL, respectively. With regard to the physical properties of fruit bodies, the springiness, cohesiveness, gumminess, and brittleness of stipe tissue were 80%, 57%, 720 g, and 57 kg, respectively. These values were lower than those of the control ('Miso'). To test the shelf life, the fruit bodies were wrapped with antifogging film and stored at $4^{\circ}C$ for 28 days and then at room temperature for 4 days; such conditions were sufficient for maintaining edibility.

• Applied Microscopy
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• v.39 no.4
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• pp.341-348
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• 2009

The crystal structure of nano-crystalline, $BaTiO_3$, with the average particle size of 100 nm was investigated using electron diffraction techniques. We characterized the precession electron diffraction system and then carried out the structure determination using precession electron diffraction and conventional selected area electron diffraction. As a result, it was revealed that $BaTiO_3$ nano-crystalline exist as a mixture of tetragonal structure and cubic structure by precession electron diffraction technique. In addition, it could be turned out that $BaTiO_3$ nano-crystalline is a core-shell structure consisted of a tetragonal phased core and a cubic phased surface layer by theoretical calculation. The thickness of the cubic surface layer was approximately 8.5 nm and the lattice parameters of cubic and tetragonal phases were a=3.999${\AA}$ and a=3.999${\AA}$, c=4.022${\AA}$, respectively. Finally, it is expected that precession electron diffraction is more useful technique for structure determination of complicated nano-crystalline materials because of its higher spatial resolution and minimization of dynamical scattering effect.

• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.47-55
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• 1998

In the search for broadband damping composites, it is desirable to have polymers with a broad and high loss region, covering the entire temperature and frequency range of interest. Interpenetrating polymer networks, IPN's, are materials composed of two or more crosslinked polymers intimately and irrevocably interwinded. The resulting distribution of microenviron-ments can result in a materials with a high mechanical loss broad end over that of either polymer component alone. In this study, several series of copolymer, crosslinked copolymer and copolymer/copolymer IPN's were synthesized for possible use as broadband damping materials. Then their dynamic tensile properties were measured and compared with the damping properties of sandwich composites. Dynamic mechanical analysis showed that the temperature of loss peak may be varied over a wide temperature range with formulation. The compatibility of IPN`s was depended on the compatibility of A and B polymers as well as crosslink density. The damping factor(tan ${\delta}_c$) of composites became greater when a polymer of approximate storage module(E`) range of 5X10$^7$ to 10$^9$ dyne/cm$^2$ and large tan ${\delta}$ at the same time was used. The damping properities of poly (2-EHA80-co-St20)/poly(2-EHA20-co-St80) IPN`s crosslinked with 3%-DEGDM were relatively better over a broad temperature range.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.829-834
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• 1998

Concerned with environmental issue, a new decomposition method for CFCs that caused the destruction of ozone layer was proposed. Using thermal plasma process, CFC113 decomposed completely. In order to quantify the tendency in decomposition and recombination of CFC113, thermodynamic equilibrium calculations were performed. The calculation was conducted with CFC113, $H_2$, $O_2$ at 1 atm and 300 K~5000 K. In the experiment, products which are generated after decomposition in the plasma were examined by varying reacting gases($H_2$, $O_2$) flow rates and the changes of inside diameters of quenching tubes. Decomposition products were analyzed using Gas Chromatograph. The results are very promising with a decomposition efficiency greater than 99.99%. As to CFC113/$H_2$=1/3, conversion to CO decreased with increasing $O_2$ ratio. When CFC113/$O_2$=1/1, 1/1.5 and 1/2, conversion to CO increases above $H_2$ ratio of 3. The change of CO conversion is not sensitive to power changes. As total flow rate increased, CO conversion was slightly decreased. When the inside diameter of the quenching tube was changed from 8mm into 4mm, CO conversion was increased due to enhanced quenching rate.