• Journal of Life Science
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• v.20 no.10
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• pp.1468-1475
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• 2010

Sulfate reduction rates (SRR) using $^{35}SO_4^{-2}$, sulfide producing rates (SPR) using gas chromatography, the number of sulfate reducing bacteria (SRB) using the most probable number (MPN) method, and soil components (moisture, ammonium, total nitrogen, total organic carbon, total carbon, total inorganic phosphorus, total phosphorus, and sulfate) using standard methods in the organic/conventional rice paddy soils, cleaned/polluted reservoir soils, and cleaned/polluted foreshore soils were studied with the change of seasons. The average SRR was more related to the number of SRB and soil components (especially nitrogen and phosphorus) than sulfate concentration. SRR was also recorded to be highest in October soil samples. However, SPR was higher in foreshore soils containing a high concentration sulfate than in fresh water soils, and it was also recorded to be higher in the polluted areas than in clean areas. From these results, we can conclude that the SRR and SPR of anaerobic environments were affected by the number of SRB, soil components and temperature.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.272-277
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• 1994

The microbial populations of exportable and domestic white ginseng powders, which have been problems in quality control, were higher than the legally-permissive level of microorganisms as $5{\times}10^{4}$/g in total bacteria and as negative coliforms. Various microorganisms contaminated in the sample were effectively decontaminated by gamma irradiation at below 10 kGy as well as ethylene oxide (EO) fumigation. The radiosens.tivity of microorganisms was the highest in coliforms, followed by molds and aerobic bacteria ($D_{10}$: 1.25 kGy). The good microbiological quality could be retained in white ginseng powders for more than 7 months of storage at $30{\pm}2^{\circ}C$ irrespective of relative humidities if products are prepared with a lower moisture content below 10% and treated by gamma irradiation at 5 to 10 kGy in an airtight packaging.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.4
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• pp.339-349
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• 2010

The uses of the polypropylene bulk bags having the loading capacities more than 500 kg are increasing in Korea recently as a storage container for rough rice. This study was performed to obtain the basic information on the changes of temperature and relative humidity in the bulk-bag-stored high moisture rough rice during waiting for drying. At the moisture content more than 22% on wet weight basis of paddy, the bulk-bag inside temperature rose up to more than $40^{\circ}C$ and then slid down during storage. For example, in case of Hwaseongbyeo, 26.5% moisture content of rough rice (MCRR) harvested at 46 days after heading (DAH) showed $54.5^{\circ}C$ of peak temperature at 66.8 hours after bulk-bag loading, 22.5% MCRR harvested at 52 DAH exhibited $42.0^{\circ}C$ at 81.1 hours, and 19.7% MCRR harvested at 55 DAH displayed $38.9^{\circ}C$ at 119.0 hours. There were a good linear relationship between peak temperatures of bulk-bag inside and moisture contents of paddy ($r^2$=0.89 in 2005, and 0.87 in 2006), while the slope and intercept of the linear regression equation was affected by the environmental conditions such as ambient temperatures and microbial flora. The peak temperatures increased with the rate of about $2.74-3.33^{\circ}C$ per every 1% increase of moisture content at higher moisture contents of paddy than 19%. The relative humidity varied depending on bulk-bag inside temperature and rough rice moisture content, and showed the range of 94.2% to 99.9% in the central point of the bulk-bag. The results suggested that a rapid drying treatment as soon as possible was needed to produce a good quality of rice when the paddy of high moisture more than 22% on wet basis was harvested in a bulk-bag especially at high ambient temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6610-6617
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• 2013

This study examined the current and future Indoor Air Quality (IAQ) control device markets and analyzed the recent studies on indoor air pollutantr emoval to develop a new technology for fine dust control. Currently, the mechanical filter technique occupies the bulk of the IAQ control market but the electronic technique is emerging as an alternative to control fine dust efficiently. Among the gaseous VOCs and fine dust particles contaminating the indoor air quality, fine dust particles are more problematic because they threaten human health by penetrating deep into the body and producing secondary contaminants by chemical reaction with VOCs. The electronic IAQ control device using dielectrophoretic and electrostatic forces is a good option for public spaces where many people pass, and at the same time, it needs to consider temperature, humidity, and the particle properties of specific areas to highlight the control efficiency. Electronic-related technology is expected to be used widely in many public/private spaces wherever a dust-free environment is required.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.261-271
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• 2007

Phytoremediation is an economic and environmentally friendly technique to remediate contaminated-soil. In this study, the effects of plants, rhizobacteria and physicochemical factors on phytoremediation have been reviewed. For successful phytoremediation, the selection of plants is primarily important. To remediate soil contaminated with petroleum hydrocarbon, raygrass (Lolium multiflorum lam), white mustard, vetch (Vicia villosa), tall fescue (Festuca arundinacea), legumes, poplar, and Pine (Pinus densiflora) were mainly applied, and the removal efficiency of petroleum hydrocarbon were ranged 68 to 99%. Corn (Zea mays), raygrass (Lolium multiflorum lam), vetch (Vicia villosa), mustard, clover (Trifolium repens), and tall fescue (Festuca arundinacea) were used for the removal of polycyclic aromatic hydrocarbon, and their removal efficiencies were 50-98%. Rhizobacteria play significant roles for phytoremediation because they can directly participate in the degradation of contaminant as well as promoting plants growth. The following rhizobacteria were preferred for phytoremediation: Azospirillum lipoferum, Enterobactor cloacae, Azospirillum brasilense, Pseudomonas putida, Burkholderia xenovorans, Comamonas testosterone, Pseudomonas gladioli, Azotobacter chroococcum, Bacillus megaterium, and Bacillus subtilis. Pysicochemical factors such as pH, temperature, nutrient, electron acceptor, water content, organic content, type of contaminants are consequential limiting factors for phytoremediation.

• Journal of Korean Society of Forest Science
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• v.109 no.1
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• pp.50-61
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• 2020

Street trees are very important to urban environments as they can alleviate air pollution. However, when ozone is absorbed through the stomata, it can induce the formation of free radicals inside the tree, negatively affecting the vegetation. The present study investigated the Air Pollution Tolerance Index (APTI) of four major street tree species: Prunus yedoensis, Zelkova serrata, Chionanthus retusus, and Pinus densiflora. Two-year-old seedlings were placed in a phytotron and fumigated with 100 nL·L^-1 (ppb) ozone for 4 weeks, following which the ascorbic acid contents, chlorophyll contents, leaf pHs, and relative water contents were measured. There was no significant difference in the APTI of Prunus yedoensis and Zelkova serrata between the ozone and control treatments. By contrast, the ozone treatment caused the APTI of Chionanthus retusus to increase and that of Pinus densiflora to decrease compared with the respective controls. These results suggest that the APTI of these tree species exhibit very different responses to ozone. Therefore, more detailed research should be conducted on a range of species in the future.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.259-264
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• 2006

This work carried out to analyze the physicochemical properties and investigate the assessment of heavy metal contamination of stream sediments of the Yudeung and the Gab streams in the Daejeon area. The pH of stream sediments of the Yudeung stream shows the range of weak acid and weak alkaline. Most of stream sediments contain about 80% sand grain and have low water and cation retention capacity. Hence the stream sediments are not suitable fur various plans to grow up. The analysis of heavy metals in the stream sediments shows that the concentration of Pb, Cr and Cd increases from upstream to down stream. It is likely that the trend has a relationship with the water. Contamination of stream water. The authors recommend that clay materials be replenished in the stream sediments to increase the self-purification capacity and to make the suitable condition for growing up of various plants, and that water quality of the stream which can Influence into the contamination of stream sediments be monitored.

• Food Science and Preservation
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• v.24 no.6
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• pp.857-864
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• 2017

To establish good storage practices for hulled barley against mycotoxin contamination, we measured occurrence of fungi and mycotoxin in hulled barley grains under various storage conditions. Hulled barley grains collected from two places were stored in five different warehouses: 1) two without temperature control, 2) one with temperature controlled at $12^{\circ}C$, 3) a chamber set at $15^{\circ}C/65%$ relative humidity, and 4) one seed storage set at $10^{\circ}C$. The samples were stored for six month with temperature and relative humidity monitored regularly. Every stored samples were retrieved after 0, 1, 3, and 6 month to investigate fungal and mycotoxin contamination. From the stored grains, Fusarium, Epicoccum, Alternaria, and Drechslera spp. were frequently detected. In the warehouses without temperature control, Fusarium and Alternaria spp. constantly decreased, whereas Drechslera spp. increased along with storage period. In the other warehouses with temperature controlled, Fusarium spp. decreased slowly and more than 2.5 log CFU/g of Fusarium spp. were detected after 6 month storage. The level of nivalenol was maintained during 0-3 month but increased after 6 month storage. There was no difference in the nivalenol levels between the warehouses. Therefore reducing storage period less than 6 months could be more effective to control nivalenol contamination in hulled barley grains.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.82-90
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• 1997

This study was conducted to establish an ideal condition for obtaining maximum extraction efficiencies using an array of soil types and under a wide variety of conditions. Nine characteristic compounds were studied: benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, n-propylbenzene, 1,2,4-trimethylbenzene, and n-butylbenzene which were found in gasoline. Increasing the moisture content resulted in decreased recovery, and recovery of hydrocarbons from wet soils was significantly lower than from dry soils. For the batch extraction process, 4 hours of extraction time was sufficient to give optimum recovery of the contaminants. With methanol as an extraction solvent, maximum recovery time appeared to be reached quicker for BTEX components than with 2-propanol. The 2 to 1 ratio of solvent/soil was chosen as a compromise to provide for the indicated minimum solvent use and high extraction efficiency. The 0.4 mg/g soil contamination was adequate to show quantitative recovery. The percent recovery of BTEX was concentration dependent more than the semivolatile compounds. Methanol and 2-propanol consistently gave higher efficiency than water. Methanol was superior to 2-propanol in removing contaminants from silty clay loam soil. Using the most efficient extraction procedure, the average recovery of the light hydrocarbons from the three soils was 66 percent. Recoveries were also dependent on soil type, solvent type, extraction time, solvent amount, contaminant concentration, and compounds volatility. This study provided a useful screening technique for procedures that can be used to remediate soils contaminated with light hydrocarbons.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.294-297
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• 2010

본 연구논문에서는 주요 대기 오염물질인 $NO_x$를 처리하기 위해 다양한 종류의 촉매를 사용하여 탈질 특성을 조사하였다. 여러 종류의 담체에 다양한 종류의 활성물질을 답지한 촉매를 사용하였으며, 고정층 반응기를 이용하여 반응온도, 공간속도, 수분함량 등과 같은 공정조건에 따른 탈질효율도 측정하였다. 전체적으로 담지된 활성물질이 증가할수록 탈질효율도 증가함을 알 수 있었다.