• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.237-242
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• 2004

Cell growth and the production of pullulan by Aureobasidium pullulan HP-2001, the UV-induced mutant of A pullulans ATCC 42023, increased with increased concentration of glucose up to 15.0% (w/v). Maximal production of pullulan in the flask scale was 27.65 g/l, when concentrations of glucose and yeast extract were 15.0 and 0.25% (w/v), respectively. Maximal conversion rate of pullulan from glucose as the carbon source was 0.37, when those of glucose and yeast extract were 5.0 and 0.15% (w/v), respectively. On the basis of total amount of pullulan, the conversion rate of pullulan from glucose, and utilization rate of glucose to cell mass and pullulan by A. pullulans HP-2001, the optimal concentrations of glucose and yeast extract for the mass production of pullulan were determined to be 10.0 and 0.25% (w/v), respectively, at which concentrations the production of pullulan and its conversion rate were 27.14 g/l and 0.27, respectively. Maximal production of pullulan with optimized concentrations of carbon and nitrogen sources by A. pullulans HP-200l in a 7-1 bioreactor was 32.12 g/l for 72 h culture, and that in a 100-1 bioreactor with the inner pressure of $0.4 kgf/cm^2$ was 36.87 g/l. Increased inner pressure of a 100-1 bioreactor resulted in a higher concentration of dissolved oxygen in the medium, which might enhance the production of pullulan by A. pullulans HP-2001.

• Membrane and Water Treatment
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• 제9권4호
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• pp.255-262
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• 2018

This study attempted to evaluate the process of self-forming dynamic membrane formation on mesh filter in membrane bioreactor with a two-stage method of batch (agitation) and continues (aeration) stage at different sludge concentrations. Four concentrations of activated sludge including $6{\pm}0.4$, $8{\pm}0.5$, $10{\pm}0.3$, $14{\pm}0.3g/L$ were used to demonstrate the optimal concentration of sludge for treating municipal wastewater and reducing fouling in dynamic membrane bioreactor. The formation time and effluent turbidity were decreased in the batch stage when increasing the activated sludge concentration. The minimum values of formation time and effluent turbidity were 14 min and 43 NTU for the optimum mixed liqueur suspended solids of $8{\pm}0.5g/L$, respectively. To improve operational condition and fouling reduction in the aeration stage, critical fluxes were measured for all concentrations by flux-step method. With increasing the sludge concentration, the relevant critical fluxes reduced. The optimum subcritical flux of $30L/m^2/h$ was applied as operating flux in the second stage. The maximum COD removal efficiency of 98% was achieved by the concentration of $8{\pm}0.5g/L$. Compressibility index of self-forming dynamic membrane and transmembrane pressure trend remained somewhat constant until the optimal concentration of $8{\pm}0.5g/L$ and thereafter they increased steeply.

• 한국토양비료학회지
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• 제48권4호
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• pp.278-284
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• 2015

In general, plant roots accumulate more heavy metals than the above ground organs such as leaf, stem, and fruit. This implies that root medicinal plants would be an issue with excessive heavy metal accumulation. Therefore, the current study was carried out to investigate the distribution of heavy metal (focused on Cd and Pb) concentrations in soils and medicinal plant roots grown in different region of Korea. Total 293 samples for each soil and plant were collected along the national wide. Soil pH, total and phytoavailable metal concentrations (1 M $NH_4NO_3$ extracted) in soils were determined and heavy metal concentrations in root of the medicinal plants were analyzed. Heavy metal concentrations of the soil samples studied were not exceeded standard limits legislated in 'Soil Environmental Conservation Act', except 2 samples for Cu. However, substantial amount of Cd was accumulated in medicinal plant roots with 29% samples exceeding the standard limit legislated in 'Pharmaceutical Affairs Act' while all plant samples were lower than the standard limit value for Pb. Also the current study demonstrated that cadmium concentrations in the roots were governed by the phytoavailable Cd in soils, which decreased as soil pH increased. From this result, application of heavy metal immobilization technique using a pH change-induced immobilizing agents can be suggested for safer root medicinal plant production.

• 한국환경과학회지
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• 제31권7호
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• pp.637-652
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• 2022

In this study, the contributions of emissions (foreign and domestic) and atmospheric physical and chemical processes to PM_2.5 concentrations were evaluated during a high PM_2.5 episode (March 24-26, 2018) observed on the Jeju Island in the spring of 2018. These analyses were performed using the community multi-scale air quality (CMAQ) modeling system using the brute-force method and integrated process rate (IPR) analysis, respectively. The contributions of domestic emissions from South Korea (41-45%) to PM_2.5 on the Jeju Island were lower than those (81-89%) of long-range transport (LRT) from China. The substantial contribution of LRT was also confirmed in conjunction with the air mass trajectory analysis, indicating that the frequency of airflow from China (58-62% of all trajectories) was higher than from other regions (28-32%) (e.g., South Korea). These results imply that compared to domestic emissions, emissions from China have a stronger impact than domestic emissions on the high PM_2.5 concentrations in the study area. From the IPR analysis, horizontal transport contributed substantially to PM_2.5 concentrations were dominant in most of the areas of the Jeju Island during the high PM_2.5 episode, while the aerosol process and vertical transport in the southern areas largely contributed to higher PM_2.5 concentrations.

• 대한본초학회지
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• 제34권5호
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• pp.39-47
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• 2019

Objectives : When herbal medicines are extracted together, they may interact with each other, leading to change of chemical characteristics. This study aimed to evaluate the influence of Atractylodes rhizomes (Atractylodes japonica, A. macrocephala, and A. chinensis) on the chemical features of the roots and rhizomes of Glycyrrhiza uralensis, which is are commonly combined with herbal medicines in many herbal formulae, when they are co-decocted. Methods : Liquiritin apioside, liquiritin, ononin, and glycyrrhizin levels of G. uralensis in hot-water extracts prepared by the combination of Atractylodes rhizomes with various weight ratios (G. uralensis : Atractylodes rhizomes = 10:0, 10:5, 10:10, and 10:20) and extraction times (60, 90, and 120 min) were quantified using a HPLC-diode array detector and compared by statistical analysis. Results : The concentrations of liquiritin apioside, liquiritin, ononin, and glycyrrhizin from G. uralensis roots and rhizomes mostly reduced when co-extracted with Atractylodes rhizomes, and the addition of A. chinensis most reduced their contents between Atractylodes combination groups. A. japonica and A. macrocephala rhizomes also showed differences of liquiritin and glycyrrhizin levels at 10 g and 20 g groups of Atractylodes rhizomes. Extraction times also affected the concentrations of liquiritin, ononin, and glycyrrhizin mostly during 60 and 90 min. Conclusions : Atractylodes rhizomes might alter the chemical characteristics of G. uralensis when these herbs are co-decocted. This study provides the understanding of the chemical interactions of herbal medicines during the extraction in hot water.

• Korean Chemical Engineering Research
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• 제46권4호
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• pp.681-685
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• 2008

Kromasil KR100-5CHI-TBB 칼럼을 사용하여 라세미 mandelic acid를 분리하였다. 분리도(resolution), 이론단수(number of theoretical plates), 용량인자(capacity factor)와 같은 크로마토그라피 변수들을 이동상의 조성(hexane/t-BME = 85/15 - 10/90)과 포름산 농도(0.1, 0.5, 1.0 v/v%)를 변화시켜 실험하여 계산하였다. 칼럼의 효율을 평가하기 위해 유속 대 이론단수를 비교하였다. 등온흡착식을 계산하기 위해 PIM(Pulse Input Method)을 사용하였고, mandelic acid의 농도가 0.1에서 0.3 mg/ml 사이일 때 L-과 D-mandelic acid가 각각 8.8분과 9.4분의 체류시간을 보였다. Mandelic acid의 등온흡착식은 0.3 mg/ml의 농도이하와 이동상 조성(hexane/t-BME = 75/25)에서 선형이었다. Mandelic acid의 농도가 증가할수록 mandelic acid는 비선형 거동을 보였고, Langmuir 등온흡착식은 L-과 D-mandelic acid의 경우 각각 $C_{S,L}=3.358C_{M,L}/(1+0.0897C_{M,L})$, $C_{S,D}=3.692C_{M,D}/(1+0.1457C_{M,D})$이었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.441-444
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• 2001

This study describes the characteristics of concentrations of pollutants such as tolal nitrogen(T-N), total phosphrous(T-P), and chemical oxgen demand(COD) at paddy areas during 2-year dry irrigation periods. Most of pollutants concentrations in drainage water are lower than those in irrigation water after early July due to large uptake of pollutants by rice crop and denitrification. For drainage water, the concentrations of pollutants are constant irrespective of discharges and the average T-N/T-P ratios water range from 14 to 44, suggesting that phosphrous is limiting.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.619-622
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• 2003

The concentrations of nutrients in precipitation increased slightly from May to June and did not change afterwards. Regarding irrigation water, the nutrient concentrations were high in the early stage of rice growth but decreased during the period of mid-June to mid-July. The concentration of Tot-N in runoff water increased significantly during the period of fertilizer application (basal, tillering, and panicle fertilization) and then decreased. The concentrations of Tot-N in runoff water ranged from 0.4 to 39.8mg/L (average of 5.9mg/L). The concentration of Tot-P in runoff water ranged from 0.0004 to 0.2084mg/L (average of 0.055mg/L). The Tot-P concentrations were high only at the early stage of rice growth after fertilizer application and did not change afterwards.

• 센서학회지
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• 제18권3호
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• pp.207-209
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• 2009

This paper describes the characteristics of poly 3C-SiC micro resonators with $3{\times}10^{17}{\sim}1{\times}10^{19}cm^{-3}$ doping concentrations. The 1.2 ${\mu}m$ thick cantilever and the 0.4 ${\mu}m$ thick doubly clamped beam resonators with different lengths were fabricated using poly 3C-SiC thin films. The characteristics of poly 3C-SiC micro resonators were evaluated by quartz and a laser vibrometer in vacuum at room temperature. The resonant frequencies of micro resonators decreased with doping concentrations owing to reduction in the Young's modulus of poly 3C-SiC thin films. It was confirmed that the resonant frequencies of poly 3C-SiC resonators are controllable by doping concentrations. Therefore, poly 3C-SiC resonators could be applied to MEMS devices and bio/chemical sensor applications.

• 원예과학기술지
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• 제16권3호
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• pp.341-343
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• 1998

몇가지 토양미생물제처리(土壤微生物劑處理)가 배추의 수량(收量), 토양(土壤)과 식물체(植物體)의 화학성분(化學成分) 및 미생물상(微生物相)에 미치는 영향(影響)을 조사(調査)하였다. BLCS cattle dropping을 제외(除外)한 모든 처리구(處理區)에서 배추의 총중(總重)과 구중(球重)이 증가(增加)되었고, 특히 MPK+Husk+Palma가 배추의 수량증가(收量增加)에 가장 효과적(效果的)이었다. 식물체(植物體)의 화학성분(化學成分)을 조사(調査)한 결과(結果), Compost에 비하여 Tomi에서 K와 Ca, Mg, Fe, Mn, 그리고 Zn의 함량(含量)이 매우 높았다. MPK+Husk+Palma에서 Mg와 Mn함량(含量)이 증가(增加)하였고, MPK+Compost에서는 K와 Mg 및 Na함량(含量)이 증가(增加)하였다. 토양(土壤)의 화학성분(化學成分)은 Tomi에서 K와 P의 함량(含量)이 높았고 Husk+Palma에서 P의 함량(含量)이 증가(增加)하였으나, 다른 처리구(處理區)에서는 차이(差異)가 없었다. 토양(土壤)의 미생물상(微生物相)을 조사(調査)한 결과(結果), 총세균수(總細菌數)는 Tomi에서 가장 높았고 Husk+Palma 및 MPK+Husk+Palma처리구(處理區)에서도 높게 나타났다. Bacillus는 MPK+Husk+Palma에서 가장 높았고 Husk+Palma와 Tomi에서도 매우 높았다. Actinomycetes와 fungi도 Tomi가 가장 높았으나, 다른 처리구(處理區) 간(間)에는 차이(差異)가 없었다.