• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.1
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• pp.81-87
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• 2018

The objective of this article is to provide analytical tools for the scattering of stratum corneum (SC) and to check whether the optical clearing agents (OCAs) could be applied in optics affecting the scattering reduction. Dark field images of tape striped corneocyte separates scattered light of the SC from others in vitro. Several optical clearing agents were tested to reduce the scattering. Physical properties of SC such as water contents, keratin configuration and volume after OCAs treatment were investigated by FT-IR and 3D laser microscope. Several reducing sugars, monomeric sugars, sugar alcohol, and hyaluronic acid, which were used as humectants in cosmetic field, also reduced scattering. However, unlike dehydration in optics, water penetrated into the keratin in SC and scattering was decreased at low concentration of OCAs. In that condition, the volume of corneocyte was increased and stiffness seemed to decrease. The analyzing of tape-stripped SC, showed the change of optical and physical properties of corneocyte by optical clearing agents. The hydration of SC layer by optical clearing agents decreased the scattering of corneocyte and thus improved the skin appearance and moisturizing effect, which are important benefits in the cosmetic field and could provide new possibility to develop skin care study targeting at SC.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.315-322
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• 2012

Alkali-activated slag (AAS) is the most obvious alternative materials that can replace OPC. But, AAS industrial usage as a structural material should be evaluated for its durability. Carbonation resistance is one of the most important factors in durability evaluation. Test results for 18 slag-based mortars activated by sodium silicate and 6 OPC mortars were obtained in this study to verify the carbonation property. Main variables considered in the study were flow, compressive strength before and after carbonation, and carbonation depth. Mineralogical and micro-structural analysis of OPC and AAS specimens prior to and after carbonation was conducted using XRD, TGA, FTIR FE-SEM. Test results showed that CHS was major hydration products of AAS and, unlike OPC, no other hydration products were found. After carbonation, CSH of hydration product in AAS turned into an amorphous silica gel, and alumina compounds was not detected. From the analysis of the results, it was estimated that the micro-structures of CSH in AAS easily collapsed during carbonation. Also, the results showed that this collapse of chemical chain of CSH lowered the compressive strength of concrete after carbonation. By increasing the dosage of activators, carbonation resistance and compressive strength were effectively improved.

• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.239-248
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• 2019

Purpose: This study aims to enhance the resistance against sulfate attack compared to ordinary Portland cement (OPC) concrete by using liquid crystal display (LCD) as binder. Method: The fundamental properties including compressive strength and porosity of concrete replaced by LCD up to 15% at increments of 5% and in turn, the weight, volume, and strength loss of LCD-mixed concrete was analyzed. Results: For the concrete substituted by 5% of LCD, it showed the highest compressive strength at 28 days of curing, and particular at immersion of $Na_2SO_4$ solution, it was achieved the lowest loss of weight, volume and strength due to an decreased porosity at capillaries. In contrast, there is no distinct difference of the sulfate attack resistance between LCD-mixed concretes under exposure of $MgSO_4$ solution, excepted for OPC concrete. Conclusion: In this study, comparison of resistance to sulfate attack between LCD-mixed concretes, and it would be proposed the possibility of LCD usage as binder through long-term verification with extended replacement ratio and identification of changes of hydrates in the cement matrix.

• Development and Reproduction
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• v.8 no.1
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• pp.49-55
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• 2004

Aquaporins(AQPs) are a family of transmembrane water channel proteins that are widely distributed in various tissues throughout the body and play a major role in Oanscellular and Oansepithelial water movement. Uterine endometrium undergoes recurrent uterine stromal edema in response to hormonal stimuli, however, the mechanism regulating the fluid transport during the estrous cycle has not been fully understood. To investigate the possible role of AQPs in water movement in uterus during the estrous cycle, expression patterns of AQP -1, -3, -4, -5, -8, and -9 UMh in mouse uterus were analyzed by using semiquantitative reverse transcription- polymerase chain reaction(RT-nR). We employed a combination of laser capture microdissection(LCM) and RT-PCR to examine the expression patterns in specific uterine cell types luminal epithelial cells(LE) and stromal cells(S). Our results showed that the level of AQP-4 mRNA was significantly increased while the level of AQP-3 mRNA was significantly decreased during the proestous through the estrus stage. In addition LCM revealed that AQP-4 and -8 mRNAs were highly expressed in LE compared with S. Taken together, these results suggest that AQPs may have an important function in physiological changes of mouse uterus during the estrous cycle.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.249-256
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• 2002

High performance concrete is prone to large autogenous shrinkage due to its low water to binder ratio (W/B). The autogenous shrinkage of concrete is caused by self-desiccation as a result of water consumption by the hydration of cement. In this study, the autogenous shrinkage of high performance concrete with and without fly ash was Investigated. The properties of fresh concrete, slump loss, air content, and flowability as well as the mechanical properties, compressive strength and modulus of elasticity, were also measured. Test results was shown that the autogenous shrinkage of concrete increased as the W/B decreased. For the same W/B, the autogenous shrinkage of high strength concrete with fly ash was considerably reduced although the development of its compressive strength was delayed at early ages. Furthermore, the autogenous shrinkage and compressive strength of high strength concrete were more rapidly developed than those of normal strength concrete. It was concluded that fly ash could improve the quality of high strength concrete with respect to the workability and autogenous shrinkage.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.120-127
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• 2011

For the development of the environment-friendly insulating composite materials, natural cellulose (wood chip and sawdust) was used as a core material and activated Hwangtoh was used as a binder. Various specimens were prepared with the water/binder ratio and natural cellulose/binder ratio. The physical properties of these specimens were then investigated through compressive and flexural strength test, absorption test, hot water resistance test, thermal conductivity, measurement of pore distribution and observation of micro-structures using scanning electron microscope (SEM). Results showed that the absorption ratio increased with the increase of natural cellulose/binder ratio but decreased remarkably with the increase of polymer/binder ratio. The compressive and flexural strength development varied appreciably with the increase of water/binder ratio and natural cellulose/binder ratio. On the other hand, thermal conductivity decreased with the increase of natural cellulose/binder ratio and polymer/binder ratio. Through SEM, it was found that activated Hwangtoh that reacted with water formed a hydrate crystal leading to the compact structure and the total pore volume of the specimen using activated Hwangtoh was smaller than that of the non-activated Hwangtoh.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.130-138
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• 2015

In this study, to examine the application of cast-in-place of high-flowable and high-strength concrete, an experimental study on the lateral pressure of a formwork was preformed. The experiment specimens, which have different casting height and casting speed were prepared. The lateral pressure and the change of temperature from test specimens were obtained. The maximum lateral pressure was shown to lateral pressure of fresh concrete. Immediately after placing, the lateral pressure starts to decrease and, after 12 hours, it showed a stabilization. The decreased tend of the lateral pressure was similar with normal-strength concrete, which appears stabilization after 3~4 hours from casting completion. The more casting speed is fast, the more maximum lateral pressure is high, but pressure reduction with the lapse of time was nearly similar. In addition, it was found that there was no direct relation between the hydration heat and the lateral pressure reduction.

• KSBB Journal
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• v.17 no.1
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• pp.49-53
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• 2002

The changes in the levels of $\gamma$ -aminobutyric acid (GABA) and some free amino acids were investigated in germinating brown rices. Ungerminated brown rices were germinated for 72 hrs by application of the following solutions: 1) distilled water, 2) 50 ppm lactic acid, 3) 5 mM glutamic acid. The GABA levels were enhanced in all germinated states of brown rices compared with ungerminated ones, highest in the germinated brown rices by 5 mM glutamic acid solution. Alanine levels were also enhanced significantly in the germinated brown rices. The levels of aspartic acid and glutamic acid were decreased significantly in all the germinated states. The levels of serine decreased during germination in the solutions of water and lactic acid were increased by the germination in the glutamic acid solution. The data show that germination of brown rices by the application of the glutamic acid solution can significantly increase the levels of GABA and can restore the serine level.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.9-15
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• 2018

According to the development and use of self-consolidating concrete in field, interest in material properties of early-age concrete is rising. Setting time with hydration process of cement is one of significant indicator to evaluate the early-age material properties of concrete, various nondestructive methods including penetration resistance measurement have been proposed to estimate setting time. This study performed an experimental approach to evaluate setting time delay in mortar adding superplasticizer using electrical resistivity measurement. For this purpose, total nine types of mortar samples were prepared, and its electrical resistivity was monitoring during 24h after mixing. From the experimental result, rising time of electrical resistivity was used to evaluate setting delay of mortar, and penetration resistance was also measured for comparison. In addition, dynamic elastic modulus and compressive strength of 1day mortar were measured to investigate a possibility the use of electrical resistivity measurement for evaluation of early-age material properties.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.2
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• pp.94-101
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• 2016

This paper presents an investigation into the durability alkali-activated materials(AAM) mortar and paste samples manufactured using fly-ash(FA) and ground granulated blast furnace slag(GGBFS) exposed to a sulfate environment with different GGBFS replace ratios(0, 30, 50 and 100%), sodium silicate modules($Ms[SiO_2/Na_2O]$ 1.0, 1.5 and 2.0) and initial curing temperatures($23^{\circ}C$ and $70^{\circ}C$). The tests involved immersions for a period of 6 months into 10% solutions of sodium sulfate and magnesium sulfate. The evolution of compressive strength, weight, length expansion and microstructural observation such as x-ray diffraction were studied. As a results, as higher GGBFS replace ratio or Ms shown higher compressive strengths on 28 days. In case of immersed in 10% sodium sulfate solution, the samples shows increase in long-term strength. However, for samples immersed in magnesium sulfate solutions, the general observation was that the compressive strength decreased after immersion. The most drastic reduction of compressive strength and expansion of weight and length occurred when GGBFS or Ms ratios were higher. Also, the XRD analysis of samples immersed in magnesium sulfate indicated that expansion of AAM caused by gypsum($CaSO_4{\cdot}2H_2O$); the gypsum increased up to 6 months continuously.