• 대한미생물학회지
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• 제20권1호
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• pp.55-63
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• 1985

Phosphate, ammonia, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate were examined for their ability to control the heat-stable enterotoxin (ST) production in succinate salts medium or in M9 medium. The results obtained were summerized as follows. 1. When the initial phosphate concentration was adjusted to 1.0mM, ST production was decreased to 80u/ml or less. But when the initial phosphate concentration was adjusted to 64mM or 100mM, enterotoxin production was 320u/ml. 2. When the initial ammonia concentration in the medium was adjusted to 1.0mM, no ST production and cell growth were observed. But when ammonia concentration was adjusted to 10mM, 19mM, 38mM or 76mM, enterotoxin production was 320u/ml. 3. Among carbon sources, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate, acetate supported the highest specific production (928 unit/O.D.) of heat-stable enterotoxin. From this results, we could assume that heat-stable enterotoxin production is controlled by stringent control mechanism. 4. When the pH of the succinate salts medium was kept between 6.2 to 6.5, no heat-stable enterotoxin production was observed, but when the pH of the medium was kept between pH 6.2 to 6.5, 267 unit/O.D. of heat-stable enterotoxin was produced. 5. Glucose inhibited the heat-stable enterotoxin production and the mechanism was assumed due to its capacity to lower the pH of the medium during catabolysis and its high metabolic energy.

• 한국환경보건학회지
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• 제16권2호
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• pp.89-95
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• 1990

This study was investigated to the energy recovery by the pyrolysis of waste tyre. the pyrolysis of the waste tyre was made by using the pyrolysis chamber for the gasification and the combustion chamber for the combustion of the pyrolysis gas. In batch system, the amount of waste tyre was put 150kg in the pyrolysis chamber and the proper air flow rate for the stable production of the pyrolysis gas was 0.95Nm$^{3}$ /min. the production time of the pyrolysis gas was stable above 210minutes, and the stable production rate was above 3.8Nm$^{3}$ /min. The production temperature of pyrolysis gas was 170$^{\circ}$C and combustion temperature of pyrolysis gas was 1,000$^{\circ}$C. The combustible component of washing gas in pyrolysis gas of waste tyre was CO, CH$_{4}$, $C_{2}H_{6}$ and $C_{3}H_{8}$, and total amount was 22.7%. Heat value of condensed material was 9,804Kcal/kg. The average concentration of air pollutants between cyclone and scrubber was CO 420.4ppm, SO$_{x}$ 349.8ppm. NO$_{x}$ 68.Sppm, HCl 24.4ppm and Dust 240.0g / Nm$^{3}$, respectively.

• 한국유기농업학회지
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• 제15권1호
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• pp.43-58
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• 2007

This study was carried out to present the measures for the stable environment-friendly rice's production, farm income increase and consumption revitalization and so on by analyzing economic effects of the environment-friendly rice's production complex by certification type, cultivation type and distribution type. Data were collected from the environment-friendly rice's production complex in Kyunggi, Kangwon, Chungnam and Chunnam provinces. Survey was conducted with sorted by organic and no-pesticide farming. Of the samples 5 types of organic farming and 4 types of no-pesticide farming were surveyed in 17 and 18 complex, respectively. The farmers income of organic and no-pesticide farming per 10a were individually about $29{\sim}68%$ and 50% higher than the conventional farming. Base on the above results, the reasonable measures fur the stable environment-friendly rice's production and distribution and consumption revitalization were to secure partnership among business, universities, government and research institutes sectors, to organize farmers group and production complex, to establish RPC for environment-friendly rice and to introduce certification system for the distribution dealers.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.13-13
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• 2022

Recently, stable crop production is threatened by the effects of climate change. In particular, it is difficult to consistently maintain agricultural policies due to large price fluctuations depending on the difference in total domestic rice production from year to year. For stable rice production amid changes in the crop growing environment, development of varieties with improved disease resistance and abiotic stress stability is becoming more important. In here, drought and cold tolerant trait have been studied. First, for the development of drought tolerant varieties, we analyzed which agricultural traits are mainly affected by domestic drought conditions. As a result, it was observed that drought caused by the lack of water during transplanting season inhibits the development of the number of tiller and reduces the yield. 'Samgang' was selected as a useful genetic resource with strong drought tolerant and stable tiller number development even under drought conditions by phenotype screening. Three of drought tolerant QTLs were identified using doubled haploid (DH) population derived from a cross between Nacdong and Samgang, a drought sensitive and a tolerant, respectively. Among these QTLs, when qVDT2 and qVDTl1 were integrated, it was investigated that the tiller number development was relatively stable in the rainfed paddy field conditions. It is known that the high-yielding Tongil-type cultivars are severely affected by cold stress throughout the entire growth stage. In this study, we established conditions that can test the cold tolerance phenotype with alternate temperature to treat low temperatures in indoor growth conditions similar to those in field conditions at seedling stage. Three cold tolerant QTLs were explored using population derived from a cross between Hanareum2 (cold sensitive variety, Tongil-type) and Unkwang (cold tolerant variety, Japonica). Among these QTLs, qSCT12 showed strong cold tolerant phenotype, and when all of three QTLs were integrated, it was investigated that cold tolerant score was relatively similar to its donor parent, Unkwang, in our experimental conditions. We are performing that development of new variety with improved cold tolerant through the introduction of these QTLs.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.558-563
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• 2001

A new alkalophilic strain of Bacillus pumilus JB¬05 producing bleach-stable and halo-tolerant alkaline protease was isolated from cement industry effluents in Karnataka, India. The effects of carbon and nitrogen sources on protease production by this alkalophilic strain were observed after a 30-h incubation. A high level of alkaline protease activity was obtained in the presence of starch as the carbon and peptone as the nitrogen sources. The partially purified enzyme showed an optimum temperature and pH activity at $58^{\circ}C$ and 10.5, respectively. The enzyme was completely inhibited by PMSF (95.0%) indicating it as a serine protease. It is bleach-stable as it retained 35% original activity in the presence of 10% (v/v) hydrogen peroxide at $30^{\circ}$C after 2 h and is halo-tolerant as it retained 70% original activity in the presence of 2.5 M sodium chloride at $30^{\circ}C$ after 2 h incubation.

• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.477-482
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• 2021

Hydrogen production, hydrogen production cost, and utilization rate were calculated assuming four cases of hydrogen production system in combination of photovoltaic power generation (PV), water electrolysis system (WE), battery energy storage system (BESS), and power grid. In the case of using the PV and WE in direct connection, the smaller the capacity of the WE, the higher the capacity factor rate and the lower the hydrogen production cost. When PV and WE are directly connected, hydrogen production occurs intermittently according to time zones and seasons. In addition to the connection of PV and WE, if BESS and power grid connection are added, the capacity factor of WE can be 100%, and stable hydrogen production is possible. If BESS is additionally installed, hydrogen production cost increases due to increase in Capital Expenditures, and Operating Expenditure also increases slightly due to charging and discharging loss. Even in a hydrogen production system that connects PV and WE, linking with power grid is advantageous in terms of stable hydrogen production and improvement of capacity factor.

• 한국수소및신에너지학회논문집
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• 제18권1호
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• pp.12-25
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• 2007

Numerical simulation of the natural gas steam reforming process for on-site hydrogen production in a $H_2$ fueling station was conducted on the basis of process material and heat balances. The effects of reforming parameters on the process efficiency of hydrogen production were investigated, and set-point values of each of the parameters to minimize the sizes of unit process equipments and to secure a stable operability of the reforming process were suggested. S/C ratio of the reforming reactants was found to be a crucial parameter in the reforming process mostly governing both the hydrogen production efficiency and the stable operability of the process. The operation of the process was regarded to be stable if the feed water(WR) as a reforming reactant could evaporate completely to dry steam through HRSG. The optimum S/C ratio was 3.0 where the process efficiency of hydrogen production was maximized and the stable operability of the process was secured. The optimum feed rates of natural gas(NGR) and WR as reforming reactants and natural gas(NGB) as a burner fuel were also determined for the hydrogen production rate of $27\;Nm^3/h$.

• Journal of Microbiology and Biotechnology
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• 제7권6호
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• pp.409-416
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• 1997

Leuconostoc sp. LAB145-3A isolated from kimchi produced a bacteriocin which was active against food pathogens, such as Listeria monocytogenes, Enterococcus faecalis, and E. faecium. Bacteriocin production occurred during the early exponential phase of growth and was stable upto the late stationary phase of growth. Optimum conditions for bacteriocin production were $37^{\circ}C$ with an initial pH of 7.0. The bacteriocin of LAB145-3A was sensitive to proteases, but stable for solvents, pH change and heat treatment. It was stable even at autoclaving temperature for 15 min. The bacteriocin exhibited a bactericidal mode of action against Lactobacillus curvatus LAB170-12. The bacteriocin produced by Leuconostoc sp. LAB145-3A was purified by CM-cellulose cation exchange column chromatography and Sephadex G-50 gel filtration. The purification resulted in an approximate 10,000-fold increase in the specific activity. Approximately 4% of the initial activity was recovered. Purified bacteriocin exhibited a single band on the SDS-PAGE with an apparent molecular weight of 4,400 daltons. This bacteriocin was named leucocin K. Leuconostoc sp. LAB145-3A had two residential plasmids with molecular sizes of 23 kb and 48 kb. A comparison of plasmid profiles between LAB145-3A and its mutants revealed that the 23 kb plasmid (pCA23) was responsible for bacteriocin production and immunity to the bacteriocin in Leuconostoc sp. LAB145-3A.

• 한국유기농업학회지
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• 제19권spc호
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• pp.6-8
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• 2011

In order to produce the organic foods in accord with international standard, organic seeds should be used in organic farming. This study was conducted to establish the stable production of organic seed of waxy com by examining the growing characteristics, seed yield, and the economy for seed production by organic farming. The optimal sowing timing for organic seed production of waxy com hybrid was within 10 days of the $1^{st}$ of May with yield of 88~90% of conventional seed production. The optimal planting density was 41,600 plants/ha ($80{\times}30$ cm) for organic seed production of waxy com. The weight of 100 seeds and seed productivity increased at the planting ratio of 2:1 mother plant:male plant. Growth and seed production were improved by removing male plant at 7~10 days after silking. Organic fertilizer (mixed oil cake) was applied at a rate of 4~6 Mg/ha before sowing. Black plastic mulching was used for weed control. In addition, sex pheromone trap and bio-control agents were used for safe pest control and low labour cost.

• International Journal of Concrete Structures and Materials
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• 제4권1호
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• pp.55-62
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• 2010

The performance evaluation of a sodium lauryl sulfate to qualify as a foaming agent is presented in this paper. When new surfactants are used a systematic study of production parameters on the foam characteristics needs to be undertaken unlike proprietary foaming agents and foam generator for which manufacturer has predefined the parameters. The relative influence of the foam parameters and optimization of factors were carried out through a systematic experiment design. The foam production parameters namely foam generation pressure and dilution ratio of foaming agents are observed to have significant effect on all foam characteristics with the exception of foam output rate on which only foam generation pressure has influence. The foam with good initial foam density need not necessarily be stable foam. The optimum levels of foam production parameters are determined for the surfactant Sodium lauryl sulfate which can be used to produce stable foam for foam concrete production.