• 한국세라믹학회지
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• 제28권12호
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• pp.981-988
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• 1991

Various crystal defects such as voids, inclusions dislocations, stacking faults and precipitates were observed in the Czochralski-grown Bi12GeO20 crystals. Particularly, precipitates were found in the whole crystals. The phase of these precipitates was identified as Bi4Ge3O12 by EPMA and transmission electron microscopy. The precipitates were produced by pulling rapidly from a non-stoichiometric charge. During the pulling of Bi12GeO20 crystals, the melt composition of stoichiometric charge was changed Bi-deficent with gradual volatilization of Bi2O3. Precipition of the second phase may have been affected by an abrube thermal stress. By adding excess Bi2O3 into the stoichiometric batch, the precipitation of Bi4Ge3O12 was suppressed. At a pulling speed of 2 mm/hr, clear and precipitate from crystals of Bi12GeO20 were grown from the melt of the Bi2O3 excess charge.

• Archives of Pharmacal Research
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• 제8권2호
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• pp.67-75
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• 1985

To find emylase inhibitors produced by microorganisms from soil, a strain which had a strong inhibitory activity against bacteria .alpha.-amylase was isolated from the soil smaple collected in Seoul. The morphological and physiological characteristics of this strain on several media and its utilization of carbon sources showed that it was one of Streptomyces specties according to the international Streptomyces Project method. The amylase inhibitor of this strain was purified by means of acetone precipitation, adsorption on Amberlite XAD-2, and column chromatography on Amberlite CG-50 and SP-Sephadex C-25. The inhibitor was stable at the pH range of 1-10 and at 100.deg.C for half an hour, and had inhibitory activities against other amylases such as salivary .alpha.-amylase, pancreatic .alpha.-amylase, fungal .alpha.-amylase and glucoamylase. The kinetic studies of the inhibitor showed that its inhibitory effect on starch hydrolysis by .alpha.-amylase was non-competitive.

• Journal of Ginseng Research
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• 제4권1호
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• pp.72-87
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• 1980

Red ginseng tails were extracted with ethanol solutions over a range of concentrations and temperature conditions. Investigations were carried out to study the effects of treatments on yields, soluble solids, saponin and precipitate occured in red ginseng extract beverage during storage. It was found that: (1) Higher concentration of ethanol at low temperature resulted in less yield of crude extract (2) The amount of precipitate in the non-purified extract beverage were less with decrease in ethanol concentration used (3) The treatment for purification of extracts and storage of purified extract at 37$^{\circ}C$ for 6 months had no effect on HPLC chromatogram pattern of saponins (4) The amount of purified extract decreased by purification treatment and more decrease was found as the temperature and concentration of ethanol increased. For Preparation of red ginseng extract beverage, the treatment of extracts with ethanol at low temperature was found to be more effective to minimize precipitation in tile beverage.

• 상하수도학회지
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• 제12권4호
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• pp.43-52
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• 1998

The purpose of this study is to establish a method of estimating the daily urban water demend using Backpropagation algorithm is part of ANN(Artificial Neural Network). This method will be used for the development of the efficient management and operations of the water supply facilities. The data used were the daily urban water demend, the population and weather conditions such as treperarture, precipitation, relative humidity, etc. Kwangju city was selected for the case study area. We adjusted the weights of ANN that are iterated the training data patterns. We normalized the non-stationary time series data [-1,+1] to fast converge, and choose the input patterns by statistical methods. We separated the training and checking patterns form input date patterns. The performance of ANN is compared with multiple-regression method. We discussed the representation ability the model building process and the applicability of ANN approach for the daily water demand. ANN provided the reasonable results for time series forecasting.

• Journal of Nutrition and Health
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• 제26권5호
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• pp.585-592
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• 1993

In order to investigate the hypocholesteremic effect of soybean perptides, soybean protein(ISP), casein(CNP), their peptic hydrolyzates fractionated by acid precipitation at different pH's(SHT, SH8, SH6, SH4, CHT, CH5, CH4) and amino acid mixtures of the same composition as the proteins(SAA, CAA) were fed to rats and the concentration of serum cholesterol was measured. Then in vitro digestibility and molecular weight distribution of the peptides by pepticpancreatic hydrolysis was measured by FPLC. The lower the in vitro digestibility of peptides is, the lower the concentration of serum cholesterol becomes(r=0.986) and the higher the ratio of macropeptides is, the lower the concentration of serum cholesterol becomes(r=-0.932) in rats. These results suggest that the in vitro digestibility of peptides has close relationship to the concentration of serum cholesterol in rats and non-digestible meacropeptides or polypeptides especially more than 1 kDa, formed through digestion in gut, may lower the serum cholesterol in rats.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.529-529
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• 2015

기후변화에 따른 자연재해로 인한 인적, 물적 피해가 매년 증가하고 있으며 기후변동에 관한 정부간 협의체 IPCC(Intergovermental Panel on Climate Change) 5차 보고서에서도 기후변화의 양상이 향후 지속 될 것이라고 전망하고 있다. 이러한 기후변화가 야기하는 부정적인 영향을 저감하기 위해 기후변화 대응을 위한 연구가 세계 곳곳에서 이루어지고 있으며 본 연구에서는 한반도에 적합한 비정상성 빈도해석을 수행하기 위하여 베이지안 기법을 이용하여 산정된 확률강우량과 전지구적 기후변화 시나리오 RCP(2.6, 4,5, 6.0, 8.5)의 다운스케일을 통하여 산정된 확률강우량의 최적 블랜딩을 통하여 비정상성 확률강우량을 산정하였다. 낙동강유역의 1973-2013년 시강우 자료를 이용한 정상성 대비 증감률은 다음과 같다(Table 1).

• 한국지구과학회지
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• 제42권5호
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• pp.556-570
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• 2021

This study presents the data analysis results of groundwater chemistry and the occurrence of fluoride in groundwater obtained from the groundwater quality monitoring network of Korea. The groundwater data were collected from the National Groundwater Information Center and censored for erratic values and charge balance (±10%). From the geochemical graphs and various ionic ratios, it was observed that the Ca-HCO₃ type was predominant in Korean groundwater. In addition, water-rock interaction was identified as a key chemical process controlling groundwater chemistry, while precipitation and evaporation were found to be less important. According to a non-parametric trend test, at p=0.05, the concentration of fluoride in groundwater did not increase significantly and only 4.3% of the total groundwater exceeded the Korean drinking water standard of 1.5 mg/L. However, student t-tests revealed that the fluoride concentrations were closely associated with the lithologies of tuff, granite porphyry, and metamorphic rocks showing distinctively high levels. This study enhances our understanding of groundwater chemical composition and major controlling factors of fluoride occurrence and distribution in Korean groundwater.

• 대한약침학회지
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• 제27권2호
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• pp.154-161
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• 2024

Objectives: The objective of this study was to assess the genotoxicity of a no-pain pharmacopuncture (NPP) extract developed in 2022 using a bacterial reverse mutation assay, aiming to further substantiate the safety profile of NPP. Methods: The genotoxicity evaluation involved a bacterial reverse mutation assay to assess the mutagenic potential of NPP extracts with and without metabolic activation. Histidine-requiring Salmonella typhimurium strains (TA98, TA100, TA1535, and TA1537) and tryptophan-requiring Escherichia coli strains (WP2uvrA) were used in the assay. Results: The NPP extract did not induce a revertant colony count exceeding two times that of the negative control at any dose level in any of the tested strains, both with and without metabolic activation. Additionally, no growth inhibition or precipitation was observed in the presence of NPP. Conclusion: Based on the findings, it can be concluded that the NPP extract exhibited no mutagenic potential in the in vitro genotoxicity tests conducted.

• 대한토목학회논문집
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• 제32권3B호
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• pp.185-192
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• 2012

본 연구에서는 가뭄 취약성 지표를 선정하고, 경향성 검정에 따른 지수 산정을 실시하였다. 4대강 살리기의 일환으로 새로이 설치될 보 중 금강 및 낙동강 유역 10개 지점을 선정하였다. 지표는 수자원, 강우, 인문 분야 등 3개 분야 10개 지표를 선정하였다. 10개 지표는 연 최저 및 평균 하천수위와 지하수위, 무강우일수, 강우집중률, 강우편차율, 1인당 가용수자원량, 물재정 건전성, 물이용 공평성으로 이루어져 있다. 10개 지표의 시계열 자료를 정리하여 Mann-Kendall, Hotelling-Pabst, 그리고 Sen trend test를 실시하여 지수를 산정하였다. 연구 결과 구미보, 상주보, 합천보 등 낙동강 유역에 위치한 연구 지점들이 대체적으로 취약한 것을 알 수 있었고, 금강유역은 낙동강에 비해 비교적 취약성이 낮은 것을 알 수 있었다.

• 한국농공학회논문집
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• 제60권3호
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• pp.37-50
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• 2018

Local climate characteristics for both urban and rural areas can be attributed to multiple factors. Two factors affecting these characteristics include: 1) greenhouse gases related to global warming, and 2) urban heat island (UHI) effects caused by changes in surface land use and energy balances related to rapid urbanization. Because of the unique hydrological and climatological characteristics of cities compared with rural and forested areas, distinguishing the impacts of global warming urbanization is important. In this study, we analyzed anthropogenic climatic changes caused by rapid urbanization. Weather elements (maximum temperature, minimum temperature, and precipitation) over the last 60 years (1955-2016) are compared in urban areas (Seoul, Incheon, Pohang, Daegu, Jeonju, Ulsan, Gwangju, Busan) and rural/forested areas (Gangneung, Chupungnyeong, Mokpo, and Yeosu). Temperature differences between these areas reveal the effects of urbanization and global warming. The findings of this study can be used to analyze and forecast the impacts of climate change and urbanization in other urban and non-urban areas.