• ALGAE
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• 제21권2호
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• pp.253-259
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• 2006

Organic substances are released from phytoplankton cells during all phases of growth. The type and amounts of organic substance excreted and the effects of nutrient limitation are often highly species-specific. Dinoflagellate, Cochlodinium polykrikoides grown in batch culture produced an exopolysaccharide. Exopolysaccharide and intracellular polysaccharide concentrations increased as C. polykrikoides cultures progressed from exponential phase, through stationary phase, to declining phase. In the exponential phase, the concentration of exopolysaccharide was relatively low, but in the stationary phase, it showed a rapid increase which seemed to coincide with the depletion of nitrate from the medium. Of the 20 amino acids analyzed, proline dominated in the organic matter of all cultures ranging from 48.2 to 79.9 nmol L–1, and constituting the 20-90% of total amino acids, and followed by histamine varying from 0.7 to 47.5 nmol L–1. Leucine and cysteine were also abundant in the stationary phase. The release rates of exopolysaccharide and intracellualr polysaccharide were higher the end of stationary phase than in the exponential phase. Exopolysaccharide concentration per cell was more than two times higher during the end of stationary phase than that in exponential phase. C. polykrikoides produced extracellular polysaccharide at a rate of 47.04 pg cell–1 day–1.

• 한국토양비료학회지
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• 제50권5호
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• pp.462-471
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• 2017

A more efficient use of nutrients from organic sources can benefit both farmers and water quality in agriculture. In this paper we reviewed information related to the regulations and guidelines of a swine liquid fertilizer to propose an establishment scheme for the official standards of swine manure slurry as a liquid fertilizer for organic farming. According to the law of establishment and designation of official standard of fertilizers, the liquid fertilizer made with pig liquid manure belongs to the byproduct fertilizer as of one of organic fertilizer. However, the official standards for byproduct fertilizers including the liquid fertilizer set by the Rural Development Administration (RDA), especially for a liquid swine manure fertilizer, should be revised to meet the goals of laws pursuing the environmentally sound agriculture, especially for organic farming because the terms and relevant standards need additional specific standards alike the standards such as impurities and parameter for declaration in EU. Therefore, it is suggested that official standards for byproduct fertilizers should be revised with respect to nutrient, salt content as of SAR and Na content instead of NaCl. Also we need to develop the maximum limit of heavy metals in soil to which the liquid fertilizer can be applied, as well as application rate depending on EC of the liquid fertilizer.

• 한국유기농업학회지
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• 제9권2호
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• pp.1-23
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• 2001

It was supposed that CSA could be one of the best way to promote the movement of organic agriculture since there is little reliability on the organically grown food by consumer. In the replies submitted to a questionnaire to farmer and consumer, both group responded that the need of development of cultivation technique for organic farming and the permitted substances for organic farming and production. Both of them also replied that it is necessary to establish the lectures or division/department for organic agriculture in the agricultural education program of University. Their response to CSA was so much positive that they are willing to participate the CSA farm as a active CSA farmers or consumers. Based on the evaluation of questionnaire survey, it was suggested to do the utmost efforts that farmer preferentially practice an organic farming , md consumer consciously buy an organic food to protect an ecosystem and environment pollution.

• 생태와환경
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• 제44권4호
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• pp.358-363
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• 2011

본 연구는 영산강수계 광주지역에 대하여 XAD와 FTIR를 이용하여 자연유기물질에 대한 분포특성을 연구하였다. XAD 8/4 resin을 이용한 NOM fractionation 분석은 친수성 및 소수성을 변별하는데 사용되어졌다. FT-IR은 자연유기물의 구조에서 기능족을 분석하는데 사용되어졌다. XAD 조사에서 영산강본류의 광주상류지점(GJ-1), 광주하류지점(GJ-2), 광주천(GJC), 광주하수처리장(GJS) 등 4개 지점에서 대부분 친수성으로 조사되었다. 다만, 3월에 GJ-1 지점에서는 소수성이 주를 이루었다. 5월에는 수온의 상승과 함께 미생물의 활성의 증가로 4개 지점 공통적으로 친수성으로 조사되었고, 10월에는 3월과 매우 유사한 결과가 되었다. FT-IR 조사에서는 넓거나 높아 뚜렷한 피크들이 주로 지방족 화합물, 특히 OH 그룹, CH, $C-H_2$, $C-H_3$ 및 C-O 알코올 그룹들로 나타났고, 이들은 친수성 물질들이다. FT-IR 조사에서 그 외의 피크들은 약간의 방향족 화합물, 특히 C=O (Ketone) 그룹이 나타났다. 결과적으로 본 연구에서 영산강수계 광주지역은 주로 친수성 물질들이며, 지방족 화합물(OH, C-H etc.)인 것으로 조사되었다.

• 유기물자원화
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• 제27권4호
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• pp.71-81
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• 2019

본 연구는 비료자원으로 이용 가능한 국내 부존자원인 농업부산물의 활용성 제고를 위해 발생량을 추정하고, 주요 비료 성분 (질소, 인산, 칼리) 함량을 선행연구 및 자료들을 수집하여 향후 수입 유박 대체를 위한 국내 자원 발굴 및 활용에 관한 기초자료로 활용하고자 하였다. 2018년 농작물 생산량과 환산계수를 활용하여 주요 34종의 농작물 부산물의 연간 발생량을 추정하였다. 전체 농업부산물 중 볏짚이 50.3%로 가장 많이 발생하였으며 그 다음 왕겨가 8.7%로 벼 재배 후 발생되는 부산물이 전체 59.0%로 대부분을 차지하였다. 또한 농촌지역에서 발생되는 부산물 40종에 대한 비료 성분 (질소, 인산, 칼리)의 함량을 목록화 하였으며, 농업부산물의 질소, 인산, 칼리 성분의 평균 함량은 각 1.43%, 0.59%, 1.90%로 나타났다. 2018년 기준 26종의 농업부산물의 연간 질소공급 잠재량을 추정한 결과 44,911톤의 질소를 공급할 수 있는 것으로 조사되었다. 조사된 농업부산물들은 질소, 인산, 칼리 등 비료 성분을 함유하고 있으나 유기질 비료의 주원료로 사용되는 아주까리 유박의 비료 성분 함량에 비해 대체적으로 낮게 나타났다. 농업부산물은 발생하는 시기나 장소, 양분 함량이 매우 다양하기 때문에 이를 효율적으로 활용하기 위한 관리방안 수립이 필요하며 국내 농업부산물을 활용한 비료 및 퇴비 연구를 통하여 수입 유박을 대체하는 자재 개발 및 보급이 요구된다.

• The Korean Journal of Physiology
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• 제2권1호
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• pp.59-71
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• 1968

The uptake of phenolsulfonphthalein (PSP) and of paraaminohippuric acid (PAH) by cortical slices of the rabbit kidney was investigated while varying the composition of medium. The overall uptake of these substances displayed typical active transport characteristics and was significantly enhanced in presence of acetate. When the phosphate buffer was used the optimal pH was 7.4 for both substances. However, when the tris-buffer was used the optimal pH was 7.4 for PSP and 8.3 for PAH. Removal of $Na^+$ from the medium resulted in a significant reduction in the uptake. Similar results, though lesser in magnitude, were obtained when either $K^+\;or\;Ca^{++}$ was removed from the medium. However, there was no additive effect when $K^+\;and/or\;Ca^{++}$ were additionally removed from the $Na^+-free$ medium. The presence of ${NH_4}^+$ greatly reduced while $Li^+\;and\;Mg^{++}$ moderately reduced the uptake of both substances. However, choline had no effect. In substrate-leached slices, acetate greatly enhance the uptake of organic acids; but this action was not demonstrable in absence of $Na^+,\;K^+\;or\;Ca^{++}$.

• 한국식품영양학회지
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• 제34권1호
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• pp.132-136
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• 2021

The purpose of this study is to measure the levels of eluted and dissolved CO2, and CO, volatile organic substances and radiation composition of Cheongsong mineral water which were collected from November 2019 to July 2020 during the autumn, spring, and summer seasons at collection points located in the upper, middle and lower spring waters. Data of the upper, middle and lower spring waters include the following: the amount of eluted water (average value±standard deviation, mL/min) was 30.07±0.52, 15.03±0.16, 23.73±0.42, and the amount of CO2 gas was 1,000 ppm or more. In addition, there was no detection of CO or total volatile organic substances (TVOC) and the radiation dose was 0.08 to 0.13. μSv/h. A blank test value of 0.08 to 0.10 μSv/h, when compared with the median value, showed a high value of 0.02 μSv/h, and the uranium test results provided by the Cheongsong-gun Office were 0.0118 mg/L (date 2019.06.18) and 0.0091 mg/L (date 2020.06.04.) respectively, which was less than the permission limit of 0.03 mg/L. However, it is believed that further research using more precise devices is needed in order to guarantee the safety and health of the water.

• Ocean and Polar Research
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• 제45권3호
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• pp.113-123
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• 2023

Humic substances are refractory organic compounds that are relatively low in biological activity but known to stimulate phytoplankton growth in estuarine and marine environments. The effect of humic substances on phytoplankton growth was investigated in the seawater zone of the Yeongsan River estuary where an episodic anthropogenic freshwater is discharged, affecting its water properties directly. Water samples and data of water properties were collected at three stations (Sts. A-C) along the channel of the seawater zone in February, May, August and November, 2009. The collected water samples were incubated after humic acids (HA) were added in mesocosm experiments. Phytoplankton (chlorophyll-a) were fractionated into net- (> 20 ㎛) and nano-size (< 20 ㎛) to examine the response of phytoplankton according to size. Their response to HA treatment was assessed by repeated measures analysis of variance (RM-ANOVA). The experiments showed that phytoplankton biomass (chlorophyll-a) significantly increased after HA were added at the stations near the sea dike. Especially, nano-sized chlorophyll-a concentrations increased significantly throughout the seasons. This indicates that understanding the behavior of refractory organic matters such as humic substances is required to better manage altered estuarine ecosystems including the Yeongsan River estuary which are affected by episodic discharge of freshwater from sea dikes.

• 한국산업보건학회지
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• 제29권3호
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• pp.310-321
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• 2019

Objectives: The purpose of this study was to investigate types and characteristics of chemical substances used in LCD(Liquid crystal display) panel manufacturing process. Methods: The LCD panel manufacturing process is divided into the fabrication(fab) process and module process. The use of chemical substances by process was investigated at four fab processes and two module processes at two domestic TFT-LCD(Thin film transistor-Liquid crystal display) panel manufacturing sites. Results: LCD panels are manufactured through various unit processes such as sputtering, chemical vapor deposition(CVD), etching, and photolithography, and a range of chemicals are used in each process. Metal target materials including copper, aluminum, and indium tin oxide are used in the sputtering process, and gaseous materials such as phosphine, silane, and chlorine are used in CVD and dry etching processes. Inorganic acids such as hydrofluoric acid, nitric acid and sulfuric acid are used in wet etching process, and photoresist and developer are used in photolithography process. Chemical substances for the alignment of liquid crystal, such as polyimides, liquid crystals, and sealants are used in a liquid crystal process. Adhesives and hardeners for adhesion of driver IC and printed circuit board(PCB) to the LCD panel are used in the module process. Conclusions: LCD panels are produced through dozens of unit processes using various types of chemical substances in clean room facilities. Hazardous substances such as organic solvents, reactive gases, irritants, and toxic substances are used in the manufacturing processes, but periodic workplace monitoring applies only to certain chemical substances by law. Therefore, efforts should be made to minimize worker exposure to chemical substances used in LCD panel manufacturing process.

• ALGAE
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• 제31권3호
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• pp.189-204
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• 2016

Microalgal bioremediation of CO₂, nutrients, endocrine disruptors, hydrocarbons, pesticides, and cyanide compounds have evaluated comprehensively. Microalgal mitigation of nutrients originated from municipal wastewaters, surface waters, and livestock wastewaters has shown great applicability. Algal utilization on secondary and tertiary treatment processes might provide unique and elegant solution on the removing of substances originated from various sources. Microalgae have displayed 3 growth regimes (autotrophic, heterotrophic, and mixotrophic) through which different organic and inorganic substances are being utilized for growth and production of different metabolites. There are still some technology challenges requiring innovative solutions. Strain selection investigation should be directed towards identification of algal that are extremophiles. Understanding and manipulation of metabolic pathways of algae will possible unfold solution to utilization of algae for mitigation of dissolve organic nitrogen in wastewaters.