• Journal of the Korean Chemical Society
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• v.50 no.1
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• pp.23-31
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• 2006

carbon modified methods were used for the preconcentration and determination of copper in some real samples using the flame atomic absorption spectrometry. The copper ions was adsorbed quantitatively on the activated carbon due to their complexation with 4- amino-2, 3-dimethyl-1-phenyl-3-pyrazoline (ADMPP) or 4-(4- methoxybenzylidenimin) thiophenole (MBITP). The adsorbed copper on solid phase was eluted quantitatively using small amount of nitric acid. The influence of important parameters including pH, amount of carrier, flow rate, amount of activated carbon and type and concentration of eluting agent for obtaining maximum recovery were investigated. The methods based on ADMPP and MBITP at optimum conditions is linear over concentration range of 0.05-1.5 g mL-1 and 0.05-1.2 g mL-1 of copper with correlation coefficient of 0.9997 and 0.9994 and both detection limit of 1.4 ng mL-1, respectively. The preconcentration leads to enrichment factor of 310 and break through volume of 1550 mL for both ligands. The method has a good tolerance limit of interfering ion and a selectivity that has been successfully applied for the determination of copper content in real sample such as tap, spring, river and waste water.

• Particle and aerosol research
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• v.13 no.4
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• pp.151-158
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• 2017

Electrostatic precipitator is widely used to remove particulate matters in indoor air and industrial flue gas due to low pressure drop and high collection efficiency. However, it has a low collection efficiency for the submicrometer sized particles. Electrospraying is a potential method to increase the particle charging efficiency, which results in increased collection efficiency. Although particle charging efficiency is highly dependent upon droplet size, the effective measuring method of the droplets is still uncertain. Tap water was electrosprayed in this study, and the images of electrosprayed droplets were taken with a high speed camera coupled with several visualization methods in order to measure the droplets size. The droplet size distribution was determined by an image processing with an image-J program. As a result, a droplet measured by a laser visualization, had a half size of that by a Xenon light visualization. In addition, the experimentally measured droplet sizes were a good agreement with the predicted values suggested by $Fern{\acute{a}}ndez$ de la Mora and Loscertales(1994).

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.790-797
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• 2011

Hydrodynamic similarity was analyzed by employing scaling factor in three phase fluidized beds. The scaling factor was defined based on the holdups of gas, liquid and solid particles and effectivity volumetric flux of fluids between the two kinds of fluidized beds with different column diameter. The column diameter of one was 0.102 m and that of the other was 0.152 m. Filtered compressed air, tap water and glass bead of which density was 2,500 kg/$m^3$ were used as gas, liquid and solid phases, respectively. The individual phase holdups in three phase fluidized beds were determined by means of static pressure drop method. Effects of gas and liquid velocities and particle size on the scaling factors based on the holdups of each phase and effective volumetric flux of fluids were examined. The deviation of gas holdup between the two kinds of three phase fluidized beds decreased with increasing gas or liquid velocity but increased with increasing fluidized particle size. The deviation of liquid holdup between the two fluidized beds decreased with increasing gas or liquid velocity or size of fluidized solid particles. The deviation of solid holdup between the two fluidized beds increased with increasing gas velocity or particle size, however, decreased with increasing liquid velocity. The deviation of effective volumetric flux of fluids between the two fluidized beds decreased with increasing gas velocity or particle size, but increased with increasing liquid velocity. The scaling factor, which was defined in this study, could be effectively used to analyze the hydrodynamic similarity in three phase fluidized processes.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.304-309
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• 2012

Size verification of small and large bubbles in a bubble column was investigated by employing the dynamic gas disengagement (DGD) method and dual electrical resistivity probe (DRP) method, simultancously. The holdups of large and small bubbles in the bubble column in a given operating condition were obtained by means of the DGD method by measuring the pressure drop variation in the column with a variation of time after stopping the gas input into the column. The size and frequency of bubbles were measured by the DRP method in the same operating condition, from which the bubble holdup of each range of size was obtained. The verification of size in determining the large or small bubbles was decided by comparing the holdups of large or small bubbles measured by the DGD method with that measured by the DRP method. Filtered compressed air and tap water were used as a gas and a continuous liquid medium. The diameter and height of the bubble column were 0.102 m and 1.5 m, respectively. The demarcation size between the large and the small bubbles in the bubble column was 4.0~5.0 mm; the demarcation size was about 5.0 mm when the gas velocity was in the relatively low range, but about 4.0 mm when the gas velocity was in the relatively high range, within this experimental conditions.

• The Korean Journal of Mycology
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• v.41 no.3
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• pp.160-166
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• 2013

Recovery of ${\alpha}$-amylase (EC 3.2.1.1), lignin peroxidase (EC 1.11.1.14), laccase (EC 1.10.3.2), xylanase (EC 3.2.1.8), ${\beta}$-xylosidase (EC 3.2.1.37), ${\beta}$-glucosidase (EC 3.2.1.21) and cellulase (EC 3.2.1.4) from spent mushroom composts (SMCs) of Pleurotus cornucopiae, Pleurotus ostreatus, Pleurotus eryngii, Hericium erinaceum, Lyophyllum ulmarium, Agrocybe cylindracea, Lentinus lepideus, and Flammulina velvtipes were investigated using different extraction buffers. The maximum recovery of the enzymes was mostly detected in SMC extracts with tap water and 0.25% Triton X-100 by shaking incubation (200 rpm) for 2 h at $4^{\circ}C$. The xylanase (152 U/g) and laccase (8.1 U/g) activities were the highest in SMC extracts from F. velvtipes and P. eryngii. In addition, high enzymatic activities of ${\alpha}$-amylase (3.6 U/g) and cellulase (3.4 U/g) was detected in SMC extract of A. cylindracea. Futhermore, cellulase and laccase activities of SMCE from P. eryngii were compared to commercial enzymes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.71-77
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• 2013

The world demand of renewable bioenergy as an alternative transportation fuel is greatly increasing. Research for bioethanol production is currently being progressed intensively throughout the world. Therefore it will be necessary to develop bioethanol production with cellulosic materials. In this study, the yield of ethanol production was evaluated by simultaneous saccharification and fermentation (SSF) using sodium hydroxide pretreated sorghum ${\times}$ sudangrass hybrids. Composition analysis of 11 varieties of sorghum ${\times}$ sudangrass hybrids was performed for selection of excellent variety to efficiently produce bioethanol. The content of cellulose, hemicellulose, lignin and ash of these varieties were 32~39%, 19~24%, 17~22% and 6~11%, respectively. Among these varieties, 4 varieties of sorghum ${\times}$ sudangrass hybrids were selected for the evaluation of ethanol yield and those were pretreated with 1 M NaOH solution at $150^{\circ}C$ for 30 min using high temperature explosion system. After pretreatment, samples were neutralized with tap water. It contained 52~57% of cellulose. Simultaneous saccharification and fermentation (SSF) was carried out for 48 h at $33^{\circ}C$ by Saccharomyces cerevisiae CHY1011 using Green star variety. The yield of ethanol was 92.4% and the amount of ethanol production was estimated at 6206 L/ha.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.105-111
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• 2013

The experiments were carried out to investigate the biocontrol potential of Lysobacter capsici YS1215 on root-knot nematode and to characterize its lytic enzyme activities. L. capsici YS1215 showed chitinase and gelatinase activities on the medium containing 0.5% chitin or 0.5% gelatin as substrates. Cell growth of L. capsici YS1215 was highest at 6 days, and the highest activities of chitinase (4.0 unit $ml^{-1}$) and gelatinase (7.43 unit $ml^{-1}$) were observed on 3 and 5 days after incubation, respectively. To investigate the effect of L. capsici YS1215 on tomato growth and nematode infection, the plants in pot trial were treated with bacterial culture (BC), half of bacterial culture (HBC), only bacterial medium (BM), tap water (TW) and commercial nematicide (CN). HBC treatd plants showed the higher shoot fresh weight and dry weight on $5^{th}$week after incubation while BM, HBC and BC had consistently higher values than TW at $9^{th}$ week. HBC appeared to be the highest shoot fresh length at $9^{th}$ week. Both CN and BC showed lower number of egg mass, root gall, and population of juveniles in soil compared to BC, HBC, BM and TW. These results suggest that L. capsici YS1215 with its strong ability of lytic enzyme production can be one of the most significant candidates for biocontrol agents against root-knot nematodes.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.941-947
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• 2005

The contamination frequency of major foodborne pathogenic bacteria was investigated from 213 seafood samples including sliced raw fish and shellfish in Busan and CyeongNam province area. Tested microorganisms were Salmonella spp. Staphyloroccus aureus, Vibrio parahaemolyticus, Escherichia coli O157:H7, Bncillus cereus, Listeria monocytogenes and Campylobacter jejuni. The frequency of isolated microorganisms was V. parahaemolyticus (30.5%), B. cereus (9.9%), S. aureus (3.8%) and other pathogenic bacteria (1.4%). from July to October, total isolation rates were greater than 50% and V. parahaemolyticus was dominant among the microorganisms isolated. The bacteria isolation rate (49.2%) in raw seafoods including shellfishes was higher than one (28.9%) in sliced raw fish. V. parahaemelyticus isolates were resistant to ampicillin (96.9%), amikacin (29.2%) and tetracycline (27.7%), and B. cereus isolates were resistant to ampicillin (100%), Penicillin G (100%), rifampicin (71.4%) and tetracycline (14.3%). The growth of V. parahaemolyticus and B. rereus was greatly inhibited below $10^{\circ}C$, but increased at ambient temperature. Washing seafood with tap water showed to reduce total count of remaining V. parahaemolyticus. Thus temperature control under $10^{\circ}C$, sufficient washing and prompt eating appeared to reduce the risk of food poisoning by these bacteria in seafoods.

• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.238-243
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• 2006

The populations of V. parahaemolyticus were enumerated in oysters collected in wholesale seafood markets in Seoul and tested in various possible condition. The populations of oysters soled in the markets were ranged $<2\sim1.4\times10^6$ MPN/100 g from April to November in 2005. In the case of oysters added with V. parahaemolyticus of $4\times10^3$ CFU/100 g, the highest population numbers were $1.4\times10^7$ CFU/100 g, $5.4\times10^5$ CFU/100 g and $2.7\times10^4$ CFU/100 g at $36^{\circ}C$ after culturing for 15 hours, at $25^{\circ}C$ after 15 hours and at $4^{\circ}C$ after 15 hours, respectively. But the difference of the populations of V. parahaemolticus in oysters stored in the icebox with ice for bulked sale and displayed in stalls on ice for the small packaged sale was not significant. In the case of oysters carried with ambient temperature at $30.8^{\circ}C$, the V. parahaemolyticus density was dramatically increased from $2.7\times10^5$ to $1.4\times10^8$ MPN/100 g. It was indicated it is important to carry the oysters to home with ice after purchase. Even after the washing two times with 21 tap water, the common cooking method in Korea was not greately make the decrease of V. parahaemolyticus density from $1.4\times10^8$ MPN/100 g to $9.0\times10^5$ MPN/100 g. So it is noticed to stored in low temperature after cooking, especially in hot seasons.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.488-496
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• 2018

This study examined the Gangwon Province's current implementation of its elimination of invasive plants and explored a plan to effectively manage invasive plants. The percentage of the distribution of the plants was 39.6% for riverside areas, 23.3% for roadside areas, 12.4% for roadside & riverside areas, and 4.6% for areas around farm land and river banks. To ensure the systematic management of invasive plants, the current study suggests a) developing an invasive plants monitoring and management system; b) reinvigorating the participation of residents, private organizations, and military posts; c) planting of native replacement plants and the conversion of the locations as attractions, and d) nurturing the project for using invasive plants. For policy directions to be pursued based on the results of the study, the following are suggested: a) improving laws and systems regarding invasive plants, b) developing a cooperative system for managing invasive plants, c) implementing the training of civilian professionals, d) implementing the elimination of invasive plants, e) developing replacement plants for cities and counties, f) fostering industries that tap into invasive plants, and g) using the Han River Water System Management Fund for funding and greater efficiency.