• Journal of the Korea Concrete Institute
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• 제16권5호
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• pp.621-626
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• 2004

The use of blast-furnace slag (BFS) in making not only normal concrete but also high-performance concrete has several advantages with respect to workability, long-term strength and durability. However, slag concrete tends to show more shrinkage than normal concrete, especially autogenous shrinkage. High autogenous shrinkage would result in severe cracking if they are not controlled properly. Therefore, in order to minimize the shrinkage stress and to ensure the service life of concrete structures, the autogenous shrinkage behavior of concrete containing BFS should be understood. In this study, small prisms made of concrete with water-binder (cement+BFS) ratio (W/B) ranging from 0.27 to 0.42 and BFS replacement level of $0\%$, $30\%$, and $50\%$, were prepared to measure the autogenous shrinkage. Based on the test results, thereafter, material constants in autogenous shrinkage prediction model were determined. In particular, an effective autogenous shrinkage defined as the shrinkage that contributes to the stress development was introduced. Moreover, an estimation formula of the 28-day effective autogenous shrinkage was proposed by considering various W/B's. Test results showed that autogenous shrinkage increased with replacement level of BFS at the same W/B. Interestingly, the increase of autogenous shrinkage is dependent on the W/B at the same content of BFS; the lower W/B, the smaller increasing rate. In concluding, it is necessary to use the combination of other mineral admixtures such as shrinkage reducing admixture or to perform sufficient moisture curing on the construction site in order to reduce the autogenous shrinkage of BFS concrete.

• Journal of the Korean Geosynthetics Society
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• 제14권2호
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• pp.89-94
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• 2015

In this study, the mixed soil with an optimum mixed ratio was suggested in order to recycle the powdered sludge of basalt in Jeju Island as the impermeable liner materials. As the results of soil laboratory tests, the grain size of the powdered sludge of basalt is less than 0.1mm and the powdered sludge was classified into ML or CL category in accordance with the Unified Soil Classification System (USCS). Also, the grain size of natural soils is ranged from 0.1 mm to 10 mm and the soils were classified into SW category in USCS. To select the optimum mixed ratio of powdered sludge, the variable permeability test was performed to various mixed soils with different powdered sludge amount under both optimum compaction and field conditions. As the results of permeability tests, the coefficient of permeability of mixed soils was decreased with increasing the mixed ratio of powdered sludge, and the mixed soil with mixed ratio of 60% has the minimum coefficient of permeability. Therefore, the optimum mixed ratio of powdered sludge is 60% for recycling the powdered sludge of basalt as the impermeable liner materials.

• Journal of the Korean earth science society
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• 제36권3호
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• pp.222-235
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• 2015

Samples were collected from both places including the coastal area within the height of 5 m above the mean sea level (msl) (DH) and the top of the coastal terrace of 10-15 m msl (KS) high in Gwangseungri, Gochanggun, Korea. To find the origin of the deposit in the coastal area, granulometric analysis and geochemical analysis were performed. The result showed that the DH samples were originated from the reddish soils overlaying weathered bedrock which presented gradual change of chemical composition from the bottom toward the top. Clay minerals were found from the DH samples. These results concluded that the DH samples were found as in-situ weathered materials. The KS samples were originated from the soil layer covering gravel layer at the foot slope of the hill along the coast. The KS samples contained different chemical compositions from the DH. It is inferred that some of this layer was disturbed or experienced the influx of foreign material. The particle size of the KS samples was different from those found on the beach. The particle size of lower parts of KS site was finer than that on the beach, but the particle size of middle part of the site was coarser than that on the beach. The sorting of the KS site was poorer than that on the beach. Thus, it is inferred that some parts of the layer were formed by short-lived high energy event rather than sustained and continuous action of tidal currents and/or waves. Analysis using an optically stimulated luminescence (OSL) method showed that the burial age of samples from KS site were found 0.65-0.71 ka. Though the characteristics of the sediment layer and forming event in this area should be further studied, it can be inferred that this sedimentary layer formed by coastal flooding with storm.

• Journal of the Korean Society of Food Science and Nutrition
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• 제35권5호
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• pp.524-529
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• 2006

Chemical compounds, hydrogen peroxide and nitrite-scavenging activities of Phellinus baumii (PB) were investigated to expand the utilization of PB as functional food material. Total mineral contents of PB was 534.3 mg% and potassium was the highest content being 224 mg%. Total and reducing sugars were 56.2% and 9.8%, respectively The contents of free amino acids (FAAs) were in a range of $16.9{\sim}765.5mg%$ with the major FAAs of phenylalanine, aspartic acid, glutamic acid, leucine, serine and valine. The contents of total phenolic compounds in methanol and hot water extracts of PB were 33.3 and 20.7 mg/100 mL, respectively and were higher than those of other solvent extracts. Hydrogen peroxide-scavenging activity (80%) of methanol extract at $10{\mu}g/mL$ for 30 min was similar to tocopherol (83.1%) as control. Nitrite-scavenging activity of extracts of methanol and hot water at 500 mg/mL and pH 1.2 were 57.3% and 51.8%, respectively and then their effects were increased by lowering pH. The present results showed that the methanol and water extracts of Phellinus baumii exhibited strong hydrogen peroxide and nitrite-scavenging activities.

• Journal of the korean academy of Pediatric Dentistry
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• 제45권3호
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• pp.344-353
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• 2018

The purposes of this study were to evaluate microleakage of Biodentine, one of the tricalcium silicate based pulp-capping materials, and to compare the shear bond strength between composite resin and Biodentine with different setting times. For microleakage evaluation, 70 bovine teeth were used. Cavities were formed on the labial surfaces and filled with Biodentine. The teeth were divided into seven groups, each consisting of 10 teeth. The specimens were prepared by applying the composite resin on the upper side after different setting times. To evaluate shear bond strength, 210 acrylic resin blocks with central grooves were prepared, and the grooves were filled with Biodentine. The acrylic resin blocks were divided into seven groups of 30 specimens each, and the specimens were prepared by applying the composite resin on the upper side after different setting times. In samples with setting time of 24 hours or longer period, the microleakage between composite resin and Biodentine was reduced significantly while the shear bond strength increased to offset the polymerization shrinkage of the composite resin. Setting Biodentine for more than 24 hours before composite resin restoration would lead to more favorable clinical result.

• Transactions of the Korean hydrogen and new energy society
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• 제17권1호
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• pp.31-38
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• 2006

There are two types of metal hydride electrodes as a negative electrode in a Ni-MH battery, $AB_2$ Zr-based Laves phases and $AB_5$ LM(La-rich mischmetal)-based alloys. The $AB_5$ alloy electrodes have characteristic properties such as a large discharge capacity per volume, easiness in activation, long cycle life and a low cost of alloy. However they have a relatively small discharge capacity per weight. The $AB_2$alloy electrodes have a much higher discharge capacity per weight than $AB_5$ alloy electrodes, however they have some disadvantages of poor activation behavior and cycle life. Therefore, in order to improve the discharge capacity of the $AB_5$ alloy electrode the Zr, Ti and V which are the alloying elements of the $AB_2$ alloys were added to the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}$ alloy which was chosen as a $AB_5$ alloy with a high capacity. The addition of Zr, Ti and V to $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}$ alloy improved the activation to be completed in two cycles. The discharge capacities of Zr 0.02, Ti 0.02 and V 0.1 alloys in $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) were respectively 346, 348 and 366 mAh/g alloy. The alloy electrodes, Zr 0.02, Ti 0.05 and V 0.1 in $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V), have shown good cycle property after 200 cycles. The rate capability of the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) alloy electrodes were very good until 0.6 C rate and the alloys, Zr 0.02, Ti 0.05 and V 0.1, have shown the best result as 92 % at 2.4 C rate. The charge retention property of the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) alloys was not good and the alloys with M content from 0.02 to 0.05 showed better charge retention properties.

• The Korean Journal of Food And Nutrition
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• 제25권4호
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• pp.729-736
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• 2012

The purpose of this study is to determine the possibility of using cultured wild ginseng roots as a natural health food source. To accomplish this purpose, the contents of general and antioxidative nutrients of cultured wild ginseng roots were measured. The contents of carbohydrate, crude protein, crude lipid and ash are 61.72%, 17.36%, 0.23% and 10.90%, respectively. Further, the calories of cultured wild ginseng roots were 323.97 kcal. Total dietary fiber was 82.13%. The protein contained a total of 18 different kinds of amino acids. The contents of amino acids were 16.15 g. The K was the largest mineral followed by P, Ca, and Mg, which means cultured wild ginseng roots is alkali material. The contents of saturated fatty acids and unsaturated fatty acids were 0.23 g, and 0.62 g, respectively. Crude saponine content was 25.87 mg/g. Total phenolic contents of cultured wild ginseng roots were 11.2mg/g, and total flavonoids contents were estimated as 4.2mg/g. The electron donating ability of cultured wild ginseng roots were 24.7~31.6%. The nitrite scavenging activity was pH dependent, and was highest at pH 1.2 and lowest at pH 6.0. The cultured wild ginseng roots extract showed the highest reducing power (0.06) at the concentration of $1,000{\mu}g/m{\ell}$. Based on the above results, we deemed that the cultured wild ginseng roots might have potential antioxdant activities.

• The Korean Journal of Food And Nutrition
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• 제25권4호
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• pp.842-849
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• 2012

The purpose of this study is to determine the possibility of using Agarum cribrosum as a natural health food source. To accomplish this purpose, the contents of the general and antioxidant activities of Agarum cribrosum were measured. The contents of carbohydrate, crude protein, crude lipid and ash were 45.4%, 15.0%, 2.3% and 33.1%. The calories of Agarum cribrosum were 262.3 kcal and total dietary fiber of Agarum cribrosum was 34.0%. The protein contained a total of 18 different kinds of amino acids. The content of amino acids was 12,402.42 mg/100 g. The K was the largest mineral followed by Ca, Na and Mg, implying that Agarum cribrosum is an alkali material. The antioxidant activity of Agarum cribrosum was assessed by various radical scavenging assays using DPPH (2,2-diphenyl-1-picrylhydrazyl), FRAP (ferric ion reducing antioxidant power), reducing power, and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)). All antioxidant activity of Agarum cribrosum extract increased the concentration of the dependents. Total phenolic contents of Agarum cribrosum extract were $34.1{\pm}2.56mg/g$, and total flavonoids contents were estimated at $4.9{\pm}0.26mg/g$. General nutrients and other antioxidant bioactive materials in Agarum cribrosum were also potential materials for good health food. It is expected that a follow-up study of Agarum cribrosum through developing processed food and evaluation of their functional properties would provide useful information or sources of functional foods.

• Journal of Society of Preventive Korean Medicine
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• 제11권1호
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• pp.65-84
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• 2007

In this study, the researcher tried to present the groundwork to prepare the oriental medical yangseng plan for the future obesity with the comparison between yangseng level and the obesity of workers. The researcher made up the questionnaire which asks the general character, health-related character and yangseng level, projected among 560 people. All collected material was analyzed by SPSS and tested by T-test and ANOVA. 1. The general yangseng level average is 3.27, morality yangseng 3.90, sleep yangseng 3.39, mind yangseng 3.31, sex life yangseng 3.30, exercise yangseng 3.15, activities and rest yangseng 3.08, diet yangseng 2.94, seasonal yangseng 2.84. The highest is morality yangseng and seasonal yangseng is the lowest. 2. In the aspect of yangseng level: Having a spouse, Non-smoking, Regular exercising, Sufficient sleeping have higher yangseng levels. 3. Obesity related index is changing into the higher level when he/she is older, more paid, more job experience, more education background but less metabolic calory. And drinking and regular exercising have relativity with body composition analysis. 4. After comparing yangseng level with body composition analysis, we can easily find that the more visceral fat, the higher WHR has a high yangseng level. The more mineral also has a high mind yangseng and a low diet yangseng. The visceral fat level has a high yangseng level when higher morality yangseng and mind yangseng are getting higher and higher. And sex life yangseng shows that the highest yangseng level is from 9-10 visceral fat and the lowest yangseng level is from below 4 visceral fat. The higher WHR, the higher morality, mind and sleep yangseng. The heavier, the lower diet yangseng. The mind yangseng was very high when body fat rate was higher. The more body fat, the higher morality yangseng. The higher yangseng, when we have more muscle. Yangseng level and obesity of laborer has a close relationship with individual character and daily habits. Also, relevance can be easily found between yangseng level and obesity. Now the researcher came into the conclusion that we need to control over laborers' health and prevention of their obesity.

• Conservation Science in Museum
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• 제13권
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• pp.37-44
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• 2012

White crystals on 46 costumes excavated from Shim Su-Ryun(1534 - 1589)'s tomb were examined their characterization and distribution. In 36 of such samples, white crystals with different shape and hardness were found. The formation of crystals did not correlated with a kind and use of textiles. However, crystals were found in the back side than the front of costume, specially around the marks of shrouding dead body. White crystals from 7 textiles were investigated by EPMA, XRD, or FT-IR. The composition of white crystal was analysed by EPMA and the structure characterization of crystals was used by X-ray diffraction. FT-IR spectroscopy was applied to check if non-crystalline compounds were also present. Mg and P were detected as the main element of white crystals and these compounds were identified a struvite and newberyite, the inorganic mineral magnesium ammonium phosphates. Struvite precipitation are influenced by many factors including concentration of Mg²⁺, NH₄⁺, and PO₄^3- ions, pH, and temperatures. It is assumed that magnesium, phosphorous, ammonia, a base material of struvite comes from decomposition product of human body. Tomb covered with lime, a unique triple-structure in Joseon period offering the basic condition, an anaerobe in a coffin, and high magnesium concentration of outer coffin with lime can be inferred as important factor for precipitation of crystals.