• Economic and Environmental Geology
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• 제54권6호
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• pp.689-698
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• 2021

Since the mine reclamation scheme was implemented from 2007 in Korea, various remediation programs have been decontaminated the pollution associated with mining and 254 mines were managed to reclamation from 2011 to 2015. However, as the total amount of contaminated mine drainage has been increased due to the discovery of potential hazards and contaminated zone, more efficient and economical treatment technology is required. Therefore, in this study, the adsorption properties of arsenic was evaluated according to the adsorbents which were derived from water treatment sludge(Alum based adsorbent, ABA-500) and granular ferric hydroxide(GFH), already commercialized. The alum sludge and GFH adsorbents consisted of aluminum, silica materials and amorphous iron hydroxide, respectively. The point of zero charge of ABA-500 and GFH were 5.27 and 6.72, respectively. The result of the analysis of BET revealed that the specific surface area of GFH(257 m²·g^-1) was larger than ABA-500(126~136 m²·g^-1) and all the adsorbents were mesoporous materials inferred from N₂ adsorption-desorption isotherm. The adsorption capacity of adsorbents was compared with the batch experiments that were performed at different reaction times, pH, temperature and initial concentrations of arsenic. As a result of kinetic study, it was confirmed that arsenic was adsorbed rapidly in the order of GFH, ABA-500(granule) and ABA-500(3mm). The adsorption kinetics were fitted to the pseudo-second-order kinetic model for all three adsorbents. The amount of adsorbed arsenic was increased with low pH and high temperature regardless of adsorbents. When the adsorbents reacted at different initial concentrations of arsenic in an hour, ABA-500(granule) and GFH could remove the arsenic below the standard of drinking water if the concentration was below 0.2 mg·g^-1 and 1 mg·g^-1, respectively. The results suggested that the ABA-500(granule), a low-cost adsorbent, had the potential to field application at low contaminated mine drainage.

• Journal of the Korean Chemical Society
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• 제44권5호
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• pp.422-428
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• 2000

Optimum analytical conditions of the aluminium ion were established by flow injection analysis. Eriochrome Cyanine R(ECR) dye reacts with the aluminium ion at pH 6.0 to form a complex that exhibits maximum absorption at 535 nm. Reaction conditions including the mixing and the reaction coil length, the concentration and the pH of the buffer solutio, temperature, and injection loop volume were optimized to intro-duce this reaction into flow injection analysis. The results were as follows. A mixing coil length of 0.5 m and a reaction coil length of 4.0 m, the pH 6.0 and 1M of acetate buffer solution, the ECR concentration of 0.56 mM, the reaction temperature of 40$^{\circ}C$, the injection loop volume of 300${\mu}L$ were chosen as optimum conditions. Under these conditions the detection limit of the aluminiumion was less than 0.05 mg/L and the repeatability was better than 1%. A sampling frequency of 24 times for an hour was achieved. Interfering ions such as $F^-$, HP$O_4^{2-}$, $Fe^{2+}$, $Fe^{3+}$, $Mn^{2+}$, and other anions were tested, interference did not occur up to 1,000mg/L of ion concentration and up to 2,CO0mg/L of sulfate ion con-centration. This method was applied for the determination of aluminium ion in tap water and ground water of Jeonju and the Gochang area. The results showed that the aluminium residual in tap water of the Jeonju area was at a mean of 0.478mg/L and that in tap water of the Gochang area was at a mean of 0.278mg/L. Aluminium ion residual of the tap waters in the Jeonju area was higher level than that in the Gochang area. Aluminium residual in the ground water of the Jeonju area was 0.386 mg/L and was lower compared to 0.564 mg/L for the Gochang area.

• Journal of Life Science
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• 제12권4호
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• pp.442-451
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• 2002

In oder to investigate the effects of pH and temperature on the formation of bromate ion, which is ozonation by-products of bromine containing natural water. At the same intial pH condition, the increase of pH shown similar trends even if the reaction variables such as temperature and reaction time of ozonation were changed. As pH and temperature were increasing, the bromate concentration was increased but bromine components (HOBr/OBr-) were decreased with increasing pH from 3 to 10. Lipid peroxide content in the kidney was increased by bromate which was ingestion with 0.4g/L for 24 weeks in drinking water. Renal cytosolic enzyme system (XO, AO) of bromate group were significantly increased in comparison with those of normal group. But microsomal enzyme system were not affected. BUN level and urinary ${\gamma}$-glutamyltransferase activity were significantly increased in comparison with those of the normal. But, urinary lactate dehydrogenase activity was not affected. Renal glutathione content of rat was significantly decreased in comparison with those of normal rat given bromate. Renal glutathione S-transferase and ${\gamma}$-glutamylcysteine synthetase activities were significantly decreased in bromate-treated group, but change in renal glutathione reductase activity was not significantly different from any other experimental group.

• The Korean Journal of Food And Nutrition
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• 제28권3호
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• pp.422-427
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• 2015

This study was carried out to investigate the microbiological contamination levels of Dutch coffee products marketed in Korea. The temperature conditions during distribution and storage were also considered in this experiment. Retailed Dutch coffee were purchased from regional cafes, that is, these were self-blended by the cafes, and the marketed products were purchased from department stores and from Internet sites. The 21 samples were blended in a coffee house and 9 were obtained from department stores or were delivered from internet sites. House blended Dutch coffee contained $35.2{\pm}15.8CFU/mL$ of general bacteria, and this increased to $78.4{\pm}29.7CFU/mL$ at room temperature or $51.2{\pm}32.1CFU/mL$ after refrigeration for 5 days. These almost reached the highest criteria level for the Korea Food Sanitation Law. After 10 days, the count increased to $98.5{\pm}58.4CFU/mL$ at room temperature and $86.7{\pm}44.2CFU/mL$ at refrigeration temperature. In the Dutch coffee for distribution, $39.6{\pm}20.1CFU/mL$ of general bacteria were detected, but these did not increase after 5 days or 10 days both for room temperature and under refrigeration. The Coliform group was not found in any kind of Dutch coffee, and Fungi was founded in 60% of the Dutch samples purchased in coffee houses, department stores, and shopping sites mall. On day 0 day, $2.6{\pm}1.7CFU/mL$ of fungi were detected in the coffee house Dutch, and it did not increase significantly during the storage period at room and in a cold temperature. $3.5{\pm}3.4CFU/mL$ of fungi were detected in the Dutch coffee for distribution, and it didn't increase during further storage under any temperature.

• Journal of the East Asian Society of Dietary Life
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• 제18권4호
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• pp.446-454
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• 2008

The traditional Korean drink "Jehotang", which is one of the most commonly prescribed drugs for treatment of the heat stroke accompanied by high fever, severe sweat and thirst, it is effective far quenching thirst strengthening the stomach, stopping diarrhea and regulating intestinal function. It is also known to play a role in activating the growth of useful microbes in the intestine and in multiplying intestinal immune cells. Thus, this study investigated all aspects of the drink in an effort to develop a new functional beverage. In the course of this study, the analytical research into the literature concerning Jehotang an error in the secrets of preparing the drink. The Japanese apricot, which was given the botanical name, "Prunusmume", should only be used with the flesh (scientifically referred to as "Fructusmume"), which is fumigated with straw fire before drying. and the seed should be thrown away. The honey should only be used after it is heated with a gentle fire, before removing the white foam that farms on its surface to make the "Yeonmil". Two kinds of cooking processes were found in the ancient literature. One procedure boiling down the powered Fructus mume mixed with the Yeonmil, while the other procedure involved preparing the Fructus mume's water by adding water to it and blending the water with the Yeonmil and the rest of the raw ingredient before boiling them down. The current procedure, in which the cooking is done in a double boiler, has been widely adopted to its simplicity. The finished Jehotang is put in porcelain, kept at room temperature, and consumed after mixing with cold water.

• Korean journal of food and cookery science
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• 제15권3호
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• pp.203-209
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• 1999

The effect of several hydrocolloids on the rheological behavior of wheat flour was investigated. The influence of the selected hydrocolloids (alginate, carrageenan, CMC, guar, locustbean and xanthan) on wheat flour was tested by using two different techniques; amylograph and texture analyzer. In order to have a general overview of their effects hydrocolloids were chosen from different sources implying a broad diversity of chemical structures. The hydrocolloid addition decreased the brightness(L) but increased yellowness(b). The interaction between hydrocolloid and flour produces a slight modification of the amylogram parameters, being the most clearly affected parameter breakdown, which is increased by carrageenan, guar and xanthan. Hardness and cutting force were augmented by hydrocolloid addition, while springeness was decreased except guar and locustbean. In summary, when looking for the improvement of the noodle texture, guar, locustbean are the best candidate additives due to their effects on pasting and texture properties. These hydrocolloids increase the hardness, cutting force, gumness, chew-ness, so were thought to increase the eating quality. So, each tested hydrocolloid affected in a different way the rheological properties of wheat flour, the results obtained are important for the appropriate use of these hydrocolloid as ingredients in the noodle making process.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2019년도 학술발표회
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• pp.27-27
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• 2019

본 연구는 2019년 물관리기본법 시행과 함께 추진하는 유역물관리체제 수립과 운영에 대해 분석하고자 한다. 유역물관리는 기존의 행정체계 중심으로 추진된 물관리에서 드러난 비효율성을 극복하고 물순환에 기초하여 더욱 효율적이고 자연 친화적으로 운영하고자 하는 통합물관리의 기초이다. 유역물관리제도를 적절하게 수립하고 운영하기 위해서는 한국보다 앞서 유역물관리제도를 채택하고 운영해온 경험을 면밀하게 검토하고 장단점을 학습하여 한국 현실에 맞게 응용하는 지혜가 필요하다. 따라서 본 연구는 유역물관리제도를 성공적으로 수립하고 운영해 온 영국(잉글랜드 및 웨일스)과 프랑스 사례를 검토하여 시사점을 도출하고자 한다. 영국(잉글랜드 및 웨일스)은 1973년 유역관리청을 10개 대유역에 설치하여 유역물관리체제를 수립하고 운영하였지만 1970년대 및 1980년대 경제난을 겪으면서 관련 투자가 줄어들고 하천의 수질 악화가 지속하였으며 유역관리청과 지방정부와의 긴밀한 협조 부재로 관리의 어려움이 증가하였다. 결국, 1989년 10개의 유역관리청을 상하수도 서비스회사로 전환하고 물서비스감시청, 음용수감시국, 환경청 등의 규제기관을 수립하여 규제와 서비스를 분리한 독특한 유역물관리체제를 수립하였다. 영국의 유역물관리체제는 2000년 유럽연합물관리지침의 도입으로 10개 유역을 11개의 유역으로 재편하고 국가소통위원회, 유역소통위원회 14개, 유역파트너쉽 100개 등의 기구를 설치하여 유역거버넌스를 강화하였다. 프랑스는 1964년 새로운 물법 도입을 통해 전국을 6개 대유역으로 나누고 각 유역에 유역관리청과 유역위원회를 설치하여 본격적인 유역물관리제도를 수립하였다. 초기에는 유역관리 조직과 지방정부 간의 알력이 상당하여 수도요금에 자동부과되는 약 19%에 달하는 물세에 대한 거부감이 상당하였다. 그런데 이러한 물세가 유역관리청의 관리로 물관리 사업을 위한 펀드로 조성되고 물관리 사업 시행 시 대규모 자금을 조달할 수 있다는 실효성이 입증되면서 점차 유역관리제도가 정착할 수 있게 되었다. 프랑스는 2000년 유럽연합물관리지침의 도입으로 기존의 6개 대유역으로 관리하던 것을 13개 유역으로 재편성하였고 유역감독관 제도를 신설하여 중앙의 감독을 강화하였으며 유역관리청과 유역위원회는 더욱 강화된 거버넌스를 기반으로 효율적인 물관리를 시행하고 있다. 영국과 프랑스 사례는 한국의 유역물관리제도 수립과 운영을 위해 다음과 같은 시사점을 준다. 첫째, 2019년 시행을 앞둔 유역물관리위원회의 구성, 운영 및 역할 등에 대해서는 큰 범위에서 합의를 이뤄야 하겠지만 안정적인 운영과 사업 시행을 위해서는 긴 시간이 필요하다는 점이다. 따라서 인내심과 여유를 갖고 임하되 필요한 원칙은 면밀한 검토와 합의를 통해 세워야 할 것이다. 둘째, 거버넌스의 중요성이다. 영국 사례와 같이 이해당사자 간의 대화와 타협은 중앙정부가 주도하는 것이 아닌 유역, 지방, 도시 등에서의 이해당사자들이 함께 이룩해야 한다. 셋째, 유역관리조직을 위한 건전한 재정확보이다. 프랑스의 예와 같이 유역물관리 조직의 독립성은 재정적 독립이 근본이 되어야 하고 이것은 독립재정을 확보하여 중앙 혹은 기타 유역/지방 조직의 간섭을 피해야 한다.

• Korean Journal of Food Science and Technology
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• 제48권2호
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• pp.133-141
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• 2016

The physicochemical properties, antioxidant capacities, and sensory optimization of taro (Colocasia esculenta) under different aging conditions were investigated to develop black taro. Black taro was processed in three steps (steaming: $95{\pm}3^{\circ}C$ for 1 h; aging: 85, 90, $95^{\circ}C$ for 20, 40, and 60 h; drying: $60^{\circ}C$ for 24 h) and ground into a powder for all experiments. Black taro showed an increased crude fiber content and browning index compared to raw taro. Calcium oxalate contents, reducing sugar contents, moisture contents, and lightness values were decreased during the processing of taro. Improvements in total polyphenol content and antioxidant activity (DPPH, ABTS, FRAP) were observed in the black taro samples aged at higher temperature. Response surface methodology was used for sensory optimization, and the optimum aging conditions with the highest acceptance values were found to be $88.73^{\circ}C$ for 39.50 h for taste, and $88.82^{\circ}C$ for 42.60 h for overall acceptance.

• Korean Journal of Food Science and Technology
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• 제46권6호
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• pp.671-676
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• 2014

This study was designed to evaluate the changes in the physicochemical properties and antioxidant activity of Dutch coffee (cold brew) under different conditions of extraction and storage. Dutch coffee was extracted from ground coffee soaked in water at 4 or $20^{\circ}C$ and stored for 8 weeks at 4 or $20^{\circ}C$. The storage temperature affected the decline in pH and increase in acidity compared to the extraction temperature. The total phenol content partly decreased during the storage period. As the extraction temperature increased, the ABTS [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging activities also increased; in fact, DPPH radical-scavenging activity showed a general increase. As the storage time prolonged, the caffeine content decreased, but the contents of caffeic acid and chlorogenic acid increased. The results for all kinds of samples indicated that the general bacterial count was <1 CFU/mL, which indicated that the coffee can be stored for and consumed within 8 weeks.

• Journal of Korean Society of Forest Science
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• 제84권4호
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• pp.465-478
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• 1995

The objective of this study was to investigate the impacts of large-scale timber harvesting on the environment of a mature hardwood forest. To achieve the objective, the effects of harvesting on forest environmental factors were analyzed quantitatively using the field data measured in the study sites of Seoul National University Research Forests [(Mt.) Paekunsan] for two years(1993-1994) following timber harvesting. The field data include information on vegetation, soil mesofauna, physicochemical characteristics of soil, surface water runoff, water quality in the stream, and hillslope erosion. For comparison, field data for each environmental factor were collected in forest areas disturbed by logging and undisturbed, separately. The results of this study were as follows : The diversity of vegetational species increased in the harvested sites. However, the similarity index value of species between harvested and non-harvested sites was close to each other. Soil bulk density and soil hardness were increased after timber harvesting, respectively. The level of organic matter, total-N, avail $P_2O_5$, CEC($K^+$, $Na^+$, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$) in the harvested area were found decreased. While the population of Colembola spp., and Acari spp. among soil mesofauna in harvested sites increased by two to seven times compared to those of non-harvested sites during the first year, the rates of increment decreased in the second year. However, those members of soil mesofauna in harvested sites were still higher than those of non-harvested sites in the second year. The results of statistical analysis using the stepwise regression method indicated that the diversity of soil mesofauna were significantly affected by soil moisture, soil bulk density, $Mg^{{+}{+}}$, CEC, and soil temperature at soil depth of 5(0~10)cm in the order of importance. The amount of surface water runoff on harvested sites was larger than that of non-harvested sites by 28% in the first year and 24.5% in the second year after timber harvesting. The level of BOD, COD, and pH in the stream water on the harvested sites reached at the level of the domestic use for drinking in the first and second year after timber harvesting. Such heavy metals as Cd, Pb, Cu, and organic P were not found. Moreover, the level of eight factors of domestic use for drinking water designated by the Ministry of Health and Welfare of Korea were within the level of the first class in the quality of drinking water standard. The study also showed that the amount of hillslope erosion in harvested sites was 4.77 ton/ha/yr in the first year after timber harvesting. In the second year, the amount decreased rapidly to 1.0 ton/ha/yr. The impact of logging on hillslope erosion in the harvested sites was larger than that in non-harvested sites by seven times in the first year and two times in the second year. The above results indicate that the large-scale timber harvesting cause significant changes in the environmental factors. However, the results are based on only two-year field observation. We should take more field observation and analyses to increase understandings on the impacts of timber harvesting on environmental changes. With the understandings, we might be able to improve the technology of timber harvesting operations to reduce the environmental impacts of large-scale timber harvesting.