• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.25-32
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• 2021

For developing the durable eco-concrete, water-repellent and hydrophobic emulsion were prepared by stirring and mixing polymethyl hydrosiloxane and polyvinyl alcohol. After adding the PMHS emulsion cement paste, the hydration reaction characteristics and the change in chemical composition were analyzed through BSE and EDS analysis, and the micropores were evaluated by MIP test. Cement mixed with PMHS emulsion was analyzed to increase the hydration reactivity and to decrease the capillary porosity, but it was found that the capillary porosity varies depending on the degree of dispersion of the emulsion in the cement paste. In the case of the emulsion containing metakaolin, there was little difference in hydration degree and porosity from the case of using only the PMHS emulsion. However, when the cement surface was coated with PMHS emulsion, the contact angle was found to increase significantly compared to OPC, and it was analyzed that especially when PVA fiber was used together, it changed to a hypohydrophobic surface.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.98-141
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• 2003

Lip chapping is a serious cosmetics problem, though remedies other than moisturizing have not been proposed. We investigated changes in the surface configurations of lip corneocytes and increased CD activity and improved chapping severity. Our results suggest that lip chapping can be activities of desquamation-regulating proteinases associated with lip chapping. Using scanning electron microscopy, villus-like projections were observed on the inner surfaces of most corneocytes from normal lips, whereas those with flatter surface were predominant in chapped lips. Further, cell surface area increased with the severity of lip chapping. Cathepsin D (CD)-like and chymotrypsin-like proteinase, which are also present in skin as desquamation-regulating proteinases, were detected in lip corneocytes, though only CD activity was found to decrease in severely chapped lips. Hydration was also lower in areas of lip chapping. Sequential topical application of apricot extract essence characterized as similar to senile xerosis rather than dry skin such as winter xerosis, as it shows a delayed transition of corneocytes through the stratum corneum, and the reduced CD activity may be one of the mechanisms that is further decreased by low hydration. We propose that an enhancement of both CD activity and lip moisture may be effective to improve lip chapping.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.173-174
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• 2014

In this research, the effect of the amount of retarder and the washing timing on the quality of aggregate-exposed concrete produced by water-jet washing method is evaluated as a series of test to develop the aggregate-exposed concrete as a concrete finishing method. As a result, the amount of losing aggregate and surface mortar was increased as the dosage of retarder was increased because of the hydration retarding effect of the retarder. Furthermore, as the washing timing was extended, the mortar on the surface of the concrete was not blown by water jet with 8 to 24 ml of retarder because of hydration of cement, hence the surface quality was poor. Therefore, washing timing of one day after concrete placement showed 90 % of aggregate exposed rate and 24 ml of retarder showed the most favorable result of aggregate exposure.

• Korean Journal of Community Nutrition
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• v.11 no.1
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• pp.63-71
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• 2006

The objective of this study was to evaluate whether nutrient intakes and serum biochemical indices are associated with the skin condition of humans. Anthropometric data, skin surface hydration, ceramide content, dietary intake of nutrients and serum lipids (total cholesterol, HDL-, LDL-cholesterol, TG, MDA: malondialdehyde, TAS: total antioxidant status) were obtained from 36 healthy young women. Subjects were classified into 2 groups {LM: Low Moisture Group (n = 20) , HM: High Moisture Group (n = 16)} by forehead skin hydration. The results of this study were as follows: The average age, BMI, total body water, LBM, body fat$\%$, WHR, forehead hydration, ceramide content were 20.2 yrs, 20.7, 28.81, 39.2 kg, $28.0\%$, 0.8, $44.3\%$, and 1.05 $\mu$g/$\mu$g protein, repectively. The intakes of SF A (saturated fatty acid) , MUFA (monounsaturated fatty acid) in the HM group were significantly higher (p < 0.05) than in the LM group, but zinc intakes in the LM group were higher than in the HM group. Serum levels of TAS in the LM group (1.27 mmol/l) were significantly higher (p < 0.05) than that of in the HM group (1.20 mmol/l). Whereas other lipid levels were not significantly different, intakes of vitamin $B_{6}$ and folate showed significant positive correlation with the forehead hydration (r = 0.447, r = 0.377). Intakes of calcium and phosphorus showed significant negative correlation with forearm ceramide content (r = -0.496, r = -0.485). Several associations between nutrient intakes and skin conditions were observed, indicating that changes in baseline nutritional status may affect skin health.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3375-3379
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• 2010

Objective: The purpose of this study was to investigate the characteristics of facial skin parameters (hydration, lipid and pH) on forehead and cheek according to Ayurvedic constitution classification of Vata, Pitta and Kapha. The condition of hydration, lipid and pH in the facial skin was measured using non-invasive diagnostic technique. The collected data was analyzed with the SPSS 16.0 windows statistical program. Design: Eighty-nine Korean female subjects were recruited for this study and the average age of them was $19.9{\pm}0.84$ years. Three groups by the Ayurvedic constitution were classified by questionnaire. Results: There was a significant difference in hydration, lipid and pH according to Ayurvedic constitution. The measurement of hydration on the face depending on the constitution were shown in the order of Pitta, Kapha and Vata (p<0.001). The measurement of lipid on the face depending on the constitution were shown in the order of Kapha, Pitta and Vata (p<0.001, p<0.01). The measurement of pH on the face depending on the constitution were shown in the order of Kapha, Pitta and Vata (p<0.01). Conclusion: Facial skin surface seemed to be dependent on Ayurvedic constitution classification in Korean. These findings indicated that Ayurvedic constitution classification might be a useful esthetic treatment for caring facial skin in the future.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.57-60
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• 2008

According to the recent tendency that the buildings in the downtown concerning rising land prices and efficient use of building are gradually Manhattanized mainly the grand scaled residential buildings, structure of the buildings relates to safety and so the very thick mat concrete is selected as the foundation of architectures. Because mat concretes can not be simultaneously pour in a great quantity due to the circumstance at the field, not only the questions on the unification between the concretes pour on the upper layer and the lower layer are presented but also the cracks by the internal force from the difference of hydration exothermic period are occurred because of the time lag. Thus, this study checked the efficiency to apply "The hydration heat controlling method of mass concrete for horizontal partition pouring construction" to the skyscraper sites under construction at Haiundai in Busan. After applying this method, the result of observation that the cracks by hydration heat in all over the placement surface did never be founded. Also, in case of the economic analysis that the hydration heat reduction method using super retarding agent by difference of setting time is approximately 80% cheaper than the hydration heat reduction method by pipe cooling in the construction expenses.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.15-18
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• 2006

The test result of mat concrete applying both hydration heat difference and insulation curing method on new construction of Cheongju university educational building are summarized as following. Both fresh concrete and compressive strength properties were satisfied In aimed value. Setting time of concrete incorporating 15% of fly ash(FA) retarded 1.2 hour than control concrete. Temperature history of mali concrete indicated that the highest temperature of center was exhibited at $126^{\circ}C$ after 51 hours while the highest temperature of upper section was $10.6^{\circ}C$ after 46 hours. Temperature Difference between center and surface was managed at less than $6^{\circ}C$ during whole curing period. In addition the temperature of upper section secured more than $3.3^{\circ}C$ while the temperature of outside was indicated at less than $-10^{\circ}C$. Maturity by parts of construction secured more than $30^{\circ}C$ DD higher than outside at 3 days. The more number of times, applying insulation curing method by double bubble sheets, increased, the higher economic effect was secured. Overall it was clear that applying both double bubble sheets and hydration heat difference method on this new construction can resist hydration heat crack, early frost demage and strength decrease. It also significantly contributed quality improvement of cold weather concreting

• Applied Biological Chemistry
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• v.26 no.1
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• pp.1-7
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• 1983

The hydration of two japonica(Akibare and Milyang 15) and four indica(Milyang 30, Suweon 287, Suweon 294 and Iri 342) rice varieties was investigated in terms of mathematical rate equation. The hydration rate at temperatures of $4{\sim}32^{\circ}C$ was examined by a weighing method. The absorption of water was directly proportiponal to the square root of the hydration time(t) and was described by the diffusion equation: $1-\bar{M}=(2/\sqrt{\pi})(S/V)\;\sqrt{Dt},\;where\;\bar{M}$ is dimensionless moisture ratio, S/V is the surface-to-volume ratio and D is diffusion coefficient. The average D value was given by the Arrhenius relation: $D=D_0\;\exp(-E_a/TR)$. The activation energy was $4{\sim}5kcal/mole$. The rice samples could be classified into three groups based on hydration kinetics: Milyang 30-Suweon 287; Akibare-Milyang 15; and Suweon 294-Iri 342.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.31-36
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• 2008

This study aims to examine the effects of thickness of the concrete members and curing temperature on the properties of low heat concrete through heat of hydration analysis. Type of the members that was analyzed in the experiment is ternary mixture of ordinary portland cement, blast-furnace slag incorporating ratio(20%) and fly ash incorporating ratio(30%), which formed a mat foundation. Thicknesses of the concrete members were 1, 2 and 3(m) and three levels of curing temperatures were 10, 20 and 30(℃). They were applied to analyze the effects on the temperature and thermal cracking index. As a result, for temperature history, temperature difference between the central area and the surface tended to decrease as the thickness of the concrete members get thinner. For the temperature cracking index, on the other hand, the risk of cracking tended to decrease as the curing temperature gets higher and as the thickness gets thinner.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.959-964
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• 1996

The physicochemical and gelatinization properties of rice flours, which were prepared by polishing nonwaxy brown rice (Dongjin byeo), depending on polishing degrees were investigated. The contents of protein, ash, lipid and fiber decreased significantly as the degrees of polishing increased and water uptake of rice grains decreased during hydration. When the surface of the soaked rice grains was examined by the SEM, extensive crack formation was observed. The water binding capacities, swelling power and solubility of rice flour increased as the polishing degree increased. By the amylogram, the initial gelatinization temperatures of rice flour decreased as the polishing degree increased and the peak viscosities, the breakdown and consistency of rice flour increased as the polishing degree increased.