• Journal of Environmental Impact Assessment
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• v.27 no.5
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• pp.431-446
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• 2018

In this study, chemical characteristics of $PM_{2.5}$ samples collected in an agricultural area in Nonsan of Korea were investigated focusing on of black carbon, 3 inorganic ions and 22 trace elements. It was found that the relative error and relative standard deviation of many trace elements fell below 10%, which indicates good analytical accuracy and precision. The mean values of $PM_{2.5}$ in an agricultural area were exceeded by new Korean air quality standard of March 2018. The concentration of $PM_{2.5}$ was well correlated with those of black carbon and ions. The concentrations of trace elements were in a wide range of seven orders of a magnitude. Based on these $PM_{2.5}$ data sets, a total of 6 sources were identified using PMF (Positive Matrix Factorization; secondary aerosol (34.4%), soil/road dust (20.1%), biomass burning (16.9%), incineration/fuel combustion (13.2%), vehicle exhaust(12.2%), sea-salt (3.17%). Results of our study indicate that it is very important to control illegal burning activities in agricultural area.

• Journal of Mushroom
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• v.12 no.2
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• pp.122-126
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• 2014

In analysis of inorganic components of Miscanthus sinensis Andersson var. sinensist, Phosphate increased with the progress of growing stage. in other way potassium, calcium and magnesium was inclined to decrease. The total nitrogen content in the Miscanthus sinensis Andersson var. sinensist was increased until second age cultivated stage, but in its third year, it was decreased apparently. In other way the total carbon content of Miscanthus sinensis was not changed until second year cultivation. But rapid increasing was happen in its third year cultivation stage. 3 year cultivated Miscanthus sinensis Andersson var. sinensist which has a plentiful carbon source can be used as a good culture media source for the formation of mushroom's fruit body. When rice bran added at the amount of 20% to the keep in 65% moisture Miscanthus sinensis Andersson var. sinensist, the fermentation of culture material was well done and the temperature of $50{\sim}55^{\circ}C$ fittest for thermophilic microorganism growth was maintained for 5 days from 5 days after treatment. Rice bran 20% added to the Miscanthus sinensis Andersson var. sinensist was the fittest fermentation culture media for the Pleurotus ostreatus vinyl-bag type cultivation. When Pleurotus ostreatus was cultivated in this culture media, the yield was increased by 60% than whole Miscanthus sinensis Andersson var. sinensist containing culture media. The fermentation Miscanthus sinensis Andersson var. sinensist culture media could be substituted by 20% the sawdust in existing culture media(sawdust 50%+cottonseed bark 30%+cottonseed meal 20%).

• Membrane Journal
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• v.18 no.3
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• pp.191-197
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• 2008

In this study, we used hybrid module that was composed of packing granular activated carbon (GAC) between module inside and outside of ceramic microfiltration membrane for advanced drinking water treatment. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, synthetic water was prepared with humic acid and kaolin. Packing fraction of GAC was changed from 0 to 24.05% to see effect of packing fraction. As a result, changing curves of resistance of membrane fouling ($R_f$) and permeate flux (J) during 3 h operation were almost overlapped independent of packing fraction of GAC. Treatment efficiencies of turbidity were very high above 99.46% at all packing fractions of GAC. And treatment efficiency of NOM, which was measured by $UV_{254}$ absorbance, was the highest value of 99.43% at packing fraction of 24.05%. Then, we operated the hybrid process during 13 h at packing fraction of 24.05%. As a result, J was rapidly dropped according to increase of membrane fouling within initial 1 h of operation, and almost constant after 3 h. And treatment efficiencies of turbidity and NOM were stable and high values of 99.52% and 96.63%, respectively.

• Journal of Life Science
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• v.18 no.6
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• pp.839-844
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• 2008

A strain SH-517 which produce extracellular keratinase, was isolated from the soil of a poultry waste and a poultry factory. An isolate SH-517 was identified as Bacillus sp. based on its morphological and biochemical characteristics. The optimal culture conditions for the production of keratinase by Bacillus sp. SH-517 were investigated. The optimal medium composition for keratinase production was determined to be 2.0% chicken feather as carbon source, 0.5% beef extract as organic nitrogen source, 0.5% $KNO_3$ as inorganic nitrogen source and 0.06% KCl, 0.05% NaCl, 0.04% $KH_2PO_4$, 0.03% $K_2HPO_4$ as mineral source and 0.01% yeast extract as growth factor. The optimal temperature and pH of medium were shown $40^{\circ}C$ and 8.5 with shaking culture (180 rpm/min), respectively. The maximum keratinase production reached maximum of 125 units/ml/min after 42 hr of cultivation under the optimal culturing conditions.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.123-134
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• 2012

Hydrochemical analyses, carbon isotopic (${\delta}^{13}C_{DIC}$) analyses, and noble gas isotopic ($^3He/^4He$ and $^4He/^{20}Ne$) analyses of the Dalki carbonate waters in the Chungsong area were carried out to elucidate their hydrochemical composition and to determine the source of $CO_2$ gas and noble gases. The carbonate waters have a pH of between 5.93 and 6.33, and an electrical conductivity 1950 to $3030{\mu}S/cm$. The chemical composition of all carbonate waters was Ca(Mg)-$HCO_3$, with a high Na content. The contents of Fe, Mn, and As in some carbonate waters exceed the limit stipulated for drinking water. The concentrations of major ions are slightly higher than those reported previously. The ${\delta}^{13}C_{DIC}$ values range from -6.70‰ to -4.47‰, indicating that the carbon originated from a deep-seated source. The $^3He/^4He$ and $^4He/^{20}Ne$ ratios vary from $7.67{\times}10^{-6}$ to $8.38{\times}10^{-6}$ and from 21.32 to 725.7, respectively. On the $^3He/^4He$ versus $^4He/^{20}Ne$ diagram, the noble gas isotope ratios plot in the field of a deep-seated source, such as mantle or magma. We therefore conclude that $CO_2$ gas and noble gas in the Dalki carbonate waters originated from a deep-seated source, rather than an inorganic $CO_2$ origin as suggested in a previous study.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.17-18
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• 2011

Plasma in liquid phase has attracted great attention in the last few years by the wide domain of applications in material processing, decomposition of organic and inorganic chemical compounds and sterilization of water. The plasma in liquid is characterized by three main regions which interact each - other during the plasma operation: the liquid phase, which supply the plasma gas phase with various chemical compounds and ions, the plasma in the gas phase at atmospheric pressure and the interface between these two regions. The most complex region, but extremely interesting from the fundamental, chemical and physical processes which occur here, is the boundary between the liquid phase and the plasma gas phase. In our laboratory, plasma in liquid which behaves as a glow discharge type, is generated by using a bipolar pulsed power supply, with variable pulse width, in the range of 0.5~10 ${\mu}s$ and 10 to 30 kHz repetition rate. Plasma in water and other different solutions was characterized by electrical and optical measurements. Strong emissions of OH and H radicals dominate the optical spectra. Generally water with 500 ${\mu}S/cm$ conductivity has a breakdown voltage around 2 kV, depending on the pulse width and the repetition rate of the power supply. The characteristics of the plasma initiated in ultrapure water between pairs of different materials used for electrodes (W and Ta) were investigated by the time-resolved optical emission and the broad-band absorption spectroscopy. The deexcitation processes of the reactive species formed in the water plasma depend on the electrode material, but have been independent on the polarity of the applied voltage pulses. Recently, Coherent anti-Stokes Raman Spectroscopy method was employed to investigate the chemistry in the liquid phase and at the interface between the gas and the liquid phases of the solution plasma system. The use of the solution plasma allows rapid fabrication of the metal nanoparticles without being necessary the addition of different reducing agents, because plasma in the liquid phase provides a reaction field with a highly excited energy radicals. We successfully synthesized gold nanoparticles using a glow discharge in aqueous solution. Nanoparticles with an average size of less than 10 nm were obtained using chlorauric acid solutions as the metal source. Carbon/Pt hybrid nanostructures have been obtained by treating carbon balls, synthesized in a CVD chamber, with hexachloro- platinum acid in a solution plasma system. The solution plasma was successfully used to remove the template remained after the mesoporous silica synthesis. Surface functionalization of the carbon structures and the silica surface with different chemical groups and nanoparticles, was also performed by processing these materials in the liquid plasma.

• KSBB Journal
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• v.19 no.6 s.89
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• pp.446-450
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• 2004

We investigated the effective culture conditions of anaerobic bacteria, Enterobacter cloacae YJ-1 on hydrogen production. It was cultured with 60 mL of working volume at $35^{\circ}C$, 120 rpm for 40 h. With culture time, hydrogen production and cell growth increased, but residual glucose and pH decreased. When the $2\%$ of glucose was used as single carbon source, hydrogen production was 975.1 mL/L. To enhance hydrogen productivity, mixed carbon sources of glucose and sucrose were added. The maximum hydrogen production was earned at the mixing ratio of 25:75, and it was 1319.5 mL/L. When we added 50 mM of phosphate to protect the pH drop in culture broth, hydrogen production increased 1.3 times more than that of initial concentration. The organic nitrogen sources were more effective than inorganic nitrogen for hydrogen production. Among organic nitrogen, yeast extract was the most effective and its hydrogen production was 1691.3 mL/L. Among 9 of mineral sources, Ferric citrate and $NaMoO_4$ were especially effective, and their productions were 1782.3 mL/L and 1784.8 mL/L, respectively.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.164-167
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• 2005

The culture condition and medium composition for the enhanced mycelial growth of Lepista nuda DGUM 26501 were investigated. The optimal temperature and pH for the mycelial growth were $24^{\circ}C$ and $7.0\~8.0$, respectively. The partial pressure of oxygen for the enhanced mycelial growth was more than $10\%\;O_2$. When Czapek-Dox medium was used as a minimal medium, manitol and xylitol were very good carbon sources. Organic nitrogen sources were better than inorganic ones for mycelial growth. As the nitrogen source tested, com steep liquor, soytone and protease peptone were the best as a source of organic nitrogen sources. When ammonium phosphate as phosphorus sources was used, the enhanced mycelial growth was shown. Nicotinic acid was proved to be the most appropriate source of vitamin. After the mycelia of L. nuda DGUM 26501 was cultivated at $24^{\circ}C$ for 10 days in LNM broth (pH 7.0), the activities of extracellular enzyme were determined. The specific activity of $\alpha-amylase$ was much higher than those of other enzymes. However, little or no enzyme activities of $\beta-glucosidase$, CMCase, laccase and lipase were found.

• KSBB Journal
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• v.14 no.5
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• pp.572-577
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• 1999

A marine bacterium with highly effective agar degrading activity was ioslated from the southern sea of Korea (Chonnam, YoChon) and identified as Cytophaga sp. and named as Cytophaga sp. AYK301. This strain produced an extracellular agarase which had a high activity with agar. The optimum culture conditions for the production of agarase have been determined. For the increase of agarase productivity, 0.2% agar, 0.3% beef extract, and 0.05% NH$_4$NO$_3$ were used as carbon, organic and inorganic nitrogen source, respectively. The optimal initial pH, NaCl, culture time and temperature for the agar degrading activity were 7.5, 7.0%, 36 hr and $25^{\circ}C$, respectively. In the optimal conditions, the agarase production was increased up to more than 4.0 folds as compared to that by the basal medium.

• Ocean and Polar Research
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• v.30 no.3
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• pp.335-345
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• 2008

In order to study spatial variabilities and major controlling factors, we measured fugacity of $CO_2(fCO_2)$, temperature, salinity and nutrients in surface waters of the North Pacific($7^{\circ}30'{\sim}33^{\circ}15'N$, $123^{\circ}56'E{\sim}164^{\circ}24'W$) between September$\sim$October 2007. The North Pacific and the marginal sea were distinguished by $fCO_2$ distribution as well as unique characteristics of temperature and salinity. There was a distinct diurnal SST variation in the tropical North Pacific area, and surface $fCO_2$ coincidently showed diurnal variation. In the North Pacific area, surface $fCO_2$ was mainly controlled by temperature, while in the marginal sea area it was primarily dependent on alkalinity and dissolved inorganic carbon concentrations. Air-sea $CO_2$ flux showed a large spatial variation, with a range of $-6.10{\sim}5.06\;mmol\;m^{-2}day^{-1}$. The center of subtropical gyre of North Pacific acted as a source of $CO_2(3.09{\pm}0.95\;mmol\;m^{-2}day^{-1})$. Tropical western North Pacific (i.e. the 'warm pool' area and the subtropical western North Pacific) acted as weak sources of $CO_2$($1.07{\pm}1.20\;mmol\;m^{-2}day^{-1}$ and $0.50{\pm}0.53\;mmol\;m^{-2}day^{-1}$, respectively). In the marginal sea, however, the flux was estimated to be $-0.68{\pm}1.17\;mmol\;m^{-2}day^{-1}$, indicating that this area acted as a sink for $CO_2$.