• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.95-95
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• 2000

(No Abstract.see full/text)

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.97-103
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• 2000

지반내 중금속의 저류와 이동에 대한 가장 중요한 인자는 토양 간극수의 pH이다. 점토의 완충능을 kaolinite, hectorite, attapulgite, Na-bentonite와 같은 4가지 점토에 대하여 연구하였다. 완충능의 크기는 hectoriteattapulgite>kaolinite의 순으로 나타났다. 완충능의 크기는 지반내 탄산염 함량과 양이온 교환능력이 완충능의 크기에 가장 영향을 미치며 유기물 함량과 비표면적의 영향은 적었다. 토양의 완충능을 모델링하기 위하여 수소 이온과 토양표면의 화학반응 기간의 화학반응을 정전흡착 모델을 이용하여 모델링하였다. 또한 탄산염 함량과 양이온 교환능력을 함수로 하는 회귀식을 제안하였다. 모델 검증을 위하혀 모델 예측치와 실험치를 비교하였는데 정전 흡착모델을 이용한 예측치가 실험치와 근사한값을 나타냈다.

• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.3-10
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• 1998

Acid/Base buffer capacity of soil is very important in prediction of contaminant transport for its direct impact on pH change of the system composed of soil-contaminant-water, In this research, diffuse double layer theory as well as two layer electrostatic adsorption model are applied to develop a theoretical model of buffer capacity of soil. Model application procedures are presented as well. Buffer capacity of Georgia kaolinite and Milwhite kaolinite was measured by acid-base titration. Model prediction and experimental results are compared.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.3
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• pp.321-327
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• 1989

The buffer activities of 72 species of natural pH adjusters in Chinese herb medicine materials of food materials by 100% acetic acid$({\mu}{\ell})$ titration until pH 4.0 in the $100m{\ell}$ of 1 % solution of the pH adjuster were evaluated for their abilities to retard acidification of Kimchi. There were 14 species above 100 of buffer activity such as Glycerehizae Radix(150), Siler divaricatum Benthan et Hooker etc. among selected Chinese herb medicine materials. In selected Chinese herb medicine materials, the buffer activities of Erillae Herba+Glycyrehizae Radix, Erillae Herba+Dioscoreae Rhizoma, Erillae Herba+Glycyrehizae Radix, Erillae Herba+Dioscoreae Rhizoma, Erillae Herba+Puerariae Radix, Chrysanthenum sinense+Puerariae Radix, Alismatis Rhizoma+Angelicae gigantis and Dioscoreae Rhizoma+Puerariae Radix were above 150 by same amount blending each other. Species and buffer activities of natural pH adjusters, which are higher buffer capabilities in mushroom, bean and vegetable classes were mungbean(207). soybean(160), pease(190), fungus(225), Garland chrysanthemum(200), amaranth(175), wild sesame leaf(200), parsley(202) and green pepper(257) etc. Species and buffer activities of higher buffer capabilities of natural pH adjusters of natural blending pH adjusters which is synergistic effect or natural blending pH adjusters which is synergistic effect mixing with radish juice were mung bean+peas(272), mung bean+soy bean(282), fungus+parsley(302), Garlan chrysanthenum+amaranth(300), Garland chrysanthenum+wild sesame leaf(277), amaranth+green pepper(300) and amaranthe+parsley(280) etc and those mixing with cabbage juice were peas+fungus(202), Garland chrysanthenum(207) and fungus+parsely (205) etc.

• Tunnel and Underground Space
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• v.32 no.1
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• pp.59-77
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• 2022

Currently, the design reference temperature of the buffer material for disposing of high-level radioactive waste is less than 100℃, so if the heat dissipation capacity of the buffer material is improved, the spacings of the disposal tunnel and the deposition hole in the repository can be reduced. First of all, this study tries to analyze the criteria for thermal-hydraulic-mechanical performance of the buffer materials and to investigate the researches regarding the enhanced buffer materials with improved thermal conductivity. First, the thermal conductivity should be as high as possible and is affected by dry density, water content, temperature, mineral composition, and bentonite type. the organic content of the buffer material can have a significant effect on the corrosion performance of a canister, so the organic content should be low. In addition, hydraulic conductivity of the buffer material should be less than that of near-field rock and swelling pressure should be appropriate for buffer materials to function properly. For the development of enhanced buffer materials, additives such as sand, graphite, and graphite oxide are typically used, and a thermal conductivity can be greatly improved with a very small amount of graphite addition compared to sand.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.32-39
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• 2000

The purpose of this study was to assess the cariogenic potential of five infant formulas in vitro. as compared with 10% sucrose solution and whole bovine milk. Buffering capacities were determined by the amount of 0.1 N lactic acid consumed to titrate the 50ml specimen solutions to pH 4.0. The pH of the specimen solution inoculated by Streptococcus mutans was measured by pH meter and the surface microhardness of primary tooth enamel immersed in the specimen solution was measured by the microhardness tester, before and after 48 hours incubation. Also, the solubility of calcium from synthetic hydroxyapatite was evaluated by atomic absorption spectrophotometer The buffering capacity of infant formulas was higher than that of sucrose solution and lower than that of milk, and there were significant differences among infant formulas(P<0.01). The average pH of infant formulas after 48 hours incubation was lower than that of sucrose solution and milk, and there was significant difference between infant formulas and milk(P<0.05). There were no signifiant differences among oops in the microhardness change of primary tooth enamel and in the amount of dissolved calcium ion from synthetic hydroxyapatite after incubation with Streptococcus mutans. In conclusion, infant formulas seemed to fulfill the basic requirments to cause dental caries in primary teeth, and there were significant differences of cariogenic potential among infant formulas. Cooperative efforts of dentistry and manufacturers to reduce the cariogenic potential of infant formulas would be necessary to prevent the early childhood caries in children.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.130-139
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• 2007

This study investigated the relationship between dental caries and various oral factors in subjects with Down's syndrome. We compared 25 subjects with Down's syndrome with 63 healthy control. The dental caries index and plaque index were examined, and the total salivary immunoglobulin A and S. mutans specific salivary immunoglobulin A concentration were measured using ELISA. The S. mutans counts, Lactobacillus counts and buffer capacity were measured with Dentocult test medium. The decayed and filled surface index of deciduous teeth in subjects with Down's syndrome was lower than in controls(p<0.001). The plaque index and total salivary immunoglobulin A concentration showed no difference, S. mutans specific salivary immunoglobulin A concentration and buffer capacity in subjects with Down's syndrome were lower than in controls(p<0.001). There was no significant difference between two groups in the S. mutans counts and Lactobacillus counts. In 9-11 year age group, S. mutans counts in subjects with Down's syndrome was lower than in controls(p<0.001) and S. mutans specific salivary immunoglobulin A concentration was lower(p<0.05). There was a high correlation among deciduous dental caries index and buffering capacity and S. mutans counts.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.3
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• pp.173-179
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• 2010

In a HLW repository, the buffer is exposed to an elevated temperature due to a radioactive decay and geochemical conditions for a long time and such a hydrothermal condition may cause a significant loss of its barrier function. This study carried out hydrothermal tests with a domestic smectite clay to investigate the changes in the expandibility, layer charge, and cation exchange capacity of the smectite. When the temperature and potassium concentration in solution was increased for the hydrothermal treatments, the expandibility decreased, the layer charge negatively increased, and the CEC also decreased.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.39-46
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• 2008

The purpose of this study was to assess the cariogenic potential of infant confectionaries. In vitro, as compaired with 10% sucrose solution and whole bovine milk. Buffering capability were determined by amount of 0.1N lactic acid consumed to titrate the 50ml specimen solutions to pH 4.0. The pH of the specimen solution inoculated by streptococcus mutans was measured by pH meter and the surface microhardness tester, before and after 48 hours incubation. The buffering capacity of infant confectionaries was higher than that of sucrose solution and lower than that of milk, and there were significant difference between infant confectionaries(p<0.05). The pH of infant confectionaries after 48 hours incubation was similar to 10% sucrose solution, and there were significant difference between infant confectionaries and milk(p<0.05). The microhardness change of primary tooth enamel of infant confectionaries group after 48 hours incubation was similar to that of 10% sucrose solution, and there were significant difference between infant confectionaries and milk(p<0.05). In conclusion, infant confectionaries seemed to have the ability to cause dental caries in primary teeth, and there were significant differences of cariogenic potential among infant confectionaries. Cooperative efforts of dentistry and manufacturers to reduce the cariogenic potential of infant confectionaries would be necessary to prevent the early childhood caries in children.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1994.05a
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• pp.34-54
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• 1994

1. 고형배지특성 (1) 물리화학성 토양재배에서는 토양이 갖고 있는 다양한 완충작용, 즉 보수, 통기성, 비료성분의 보유능력이 대단히 높기 때문에 연작장해가 없는 한 작물생산에서 안정적 생산이 가능하다. 반면에 양액재배에서는 이러한 완충능을 기대하기가 어렵다. 특히 배지에 따른 물리화학성의 차이가 있고 이들 배지의 활용을 근본적으로 근권환경의 제어라는 측면에서 기존의 토양재배보다 높은 생산성과 고품질을 요구하고 있는 실정이기 때문에 배지에 따른 적정 근권환경제어가 필요하다. (중략)