• Polymer(Korea)
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• v.25 no.1
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• pp.98-107
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• 2001

Dielectric properties and shape memory characteristics of SBS composites filled with carbon black as conductive filler and (Ba,Ca)$(Sn,Ti)O_3$ or $SrTiO_3$ as dielectrics were investigated for the development of phantom model. SBS/carbon black composite showed an increment of complex dielectric constant with increasing the content of carbon black and the frequency dependence that the dielectric constant decreases with the frequency. The complex dielectric constant and the conductivity of SBS/carbon black/dielectrics composites increased with the increase of dielectrics and the characteristics of the frequency dependence also occurred by the effect of carbon black. Phantom materials with the dielectric properties and the conductivity corresponding to human tissues for the measurement of specific absorption rate(SAR) within the frequency range of current mobile phones(775MHz~2GHz) could be developed by adjusting the composition ratios of carbon black, dielectrics and SBS and by controlling the characteristic of frequency dependence of composite. From thermomechanical cycling test good shape recoverability could be obtained in SBS composite even though the residual strain was increased by the effect of filler.

• Journal of the Mineralogical Society of Korea
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• v.30 no.2
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• pp.71-81
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• 2017

Rock properties and the effects of chemicals that were used for conservation were studied for effective conservation treatment of Seated Buddha rock carving, which is composed of grayish white tuff, at Golguram Hermitage, Gyeongju. The rocks contain 3-5% montmorillonite, a swelling mineral and reacting with water, the d spacing of swelling minerals was increased (1.54-2.69%). On the one hand, the physical properties of the rock samples, such as surface hardness, water absorption rate, and porosity improved after the application of ethyl silicate-based stone strengthener. On the other, the interlayer of swelling minerals decreased and greater the of swelling mineral content, the greater is the extent of swelling (4.23-12.12%). When the ethyl silicate-based stone strengthener was applied after pretreatment with a swelling inhibitor, the physical properties were similar to those of the stone strengthener alone. There was no interlayer spacing change of swelling minerals due to swelling inhibition treatment; however, when the stone strengthener was applied after the swelling inhibitor, interlayer changes were similar to those when only the stone strengthener was treated (4.10-11.85%). Though the peak intensity of swelling minerals in X-ray diffraction pattern decreased, the effect of the swelling inhibitor was almost negligible. Therefore, it is not appropriate to use ethyl silicate-based stone strengthener for Golgulam rock containing swelling minerals and supplementing them with a swelling inhibition system is not effective. Because weathering rapidly progresses when swelling minerals contact moisture, for now, measures to prevent water contact, such as expansion of the canopy, are needed in the lower and side parts of the carving.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.765-771
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• 2019

New Korean-style clay roof tiles have been developed with a focus on significantly reducing the roof's weight while maintaining the strength, absorption rate, and freeze durability. The backflow of rain water through the gaps between roof tiles is prevented by employing baffles and a groove to accelerate water flow. With the new roof tiles, dry construction of a roof is possible without requiring soil. By using the dry construction method with the new roof tiles, a reduction in roof weight of more than 80% is possible compared to the conventional wet construction method with soil. In the case of a traditional Korean-style house with a building area of 99 square meters, the roof weight can be reduced from 135 tons to 24 tons. The new tiles satisfy the KS requirements and are more than 30% lighter than traditional roof tiles. A roof constructed using the new tiles showed no water leaks when exposed to typhoon-class winds with speeds of 17 m/s and 200 mm/h of rainfall, which is 60% higher than the Korea rainfall record. The new roof tiles also have advantages of economic efficiency, workability, maintenance, and aseismicity compared to previous Korean-style roof tiles.

• Journal of Pharmaceutical Investigation
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• v.36 no.1
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• pp.59-65
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• 2006

The purpose of this study was to evaluate the bioequivalence of two amlodipine maleate tablets, SKAD tablet (SK Pharma. Co., Ltd., Seoul, Korea, reference drug) and A-PINE tablet (Daewon Pharm. Co., Ltd., Seoul, Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty-four healthy male volunteers, $22.79\;{\pm}\;1.86$ years in age and $70.08\;{\pm}\;8.68$ kg in body weight, were divided into two groups and a randomized $2\;{\time}\;2$ crossover study was employed. After a tablet containing 6.42 mg of amlodipine maleate was orally administrated, blood was taken at predetermined time intervals over a period of 144 hr and concentrations of amlodipine in plasma were monitored using LC-MS/MS. Pharmacokinetic parameters such as $AUC_t$ (the area under the plasma concentration-time curve from time zero to 144 hr), $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were calculated and analysis of variance (ANOVA) test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$ and $C_{max}$, and untransformed $T_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for A-PINE/SKAD were $log\;0.9429{\sim}log \;1.1476$ and $log\;0.9l46{\sim}log\;1.1488$, respectively. Since these values were within the acceptable bioequivalence intervals of $log\;0.80{\sim}log\;1.25$, recommended by KFDA, it was concluded that A-PINE tablet was bioequivalent to SKAD tablet, in terms of both rate and extent of absorption.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.5
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• pp.345-357
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• 2011

Recently, as part of diversifying energy sources and earth environmental issues, technology development of new renewable energy using wave energy is actively promoted and commercialized around Europe and Japan etc. In particular, OWC(Oscillating Water Column) wave power generation system using air flow induced by vertical movement of the water surface by waves in an air-chamber within caisson is known as the most efficient wave energy absorption device and therefore, is one of the wave power generation apparatus the closest to commercialization. This study examines air flow velocity, which operates turbine(Wells turbine) directly in oscillating water column type wave power generation structure from two-and three-dimensional numerical experiments and discusses optimal shape of oscillating water column type wave power generation structure by estimating the maximum flow rate of air according to change in shape. The three-dimensional numerical wave flume was applied in interpretation for this study which is the model for the immiscible two-phase flow based on the Navier-Stokes Equation. From this, it turned out that size of optimal shape appears differently according to the incident wave period and air flow is maximized at the period where minimum reflection ratio occurs.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.2
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• pp.109-112
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• 2014

A porous ceramic which has fine porosity and small specific gravity is made with Cenosphere and Ball Clay under condition of $1,250^{\circ}C$ in calcination temperature and 30 minutes of calcination time. The average size of porous ceramic was about $2.5{\times}10^{-5}$ m and pores are well developed. The void-fraction of porous ceramic was 67.1% under the input of Cenosphere and Ball clay with the weight ratio of 100 to 5. However, as weight ratio of Ball Clay increased to 20, 40, 100, the void fraction decreased to 58.4, 56.7, 47% respectively. When the weight ratio of Cenosphere and Ball Clay was 100 to 100, the apparent density of porous ceramic was $1.04g/cm^3$. which is twice the density when the weight ratio of Ball Clay was 5. On the other hand, absorption rate decreased by at least 100%. In condition of weight ratio of Cenosphere and Ball Clay was 100 to 100, compressive strength of porous ceramic was 30 (MPa), improve by about 76% or more when the weight ratio of Ball Clay was 5.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.1
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• pp.15-23
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• 1985

Growth response and evapotranspiration of tobacco as to each soil moisture condition treated with different height of ground water table such as 30cm, 100cm, 170cm, and 230cm were investigated. The results obtained were as follows; 1. Soil water potential in the rhizosphere (25cm depth from surface) treated with ground water table (G.W.T) of 230 cm was less than -6.5 bar at 60 days after transplanting. 2. Dry weight of leaves per plant was the highest in the pot treated with 100 cm G.W.T and was the lowest in the pot treated with 230 cm G.W.T.. Leaves/Stem ratio of dry weight was the lowest in the pot treated with 230 cm G.W.T. This would show that extension of leaves as compared with elongation of stem was suppressed. .3. In the roster stress condition of 230 cm G.W.T., extension of leaves was continued until the latter growth stage, Relative growth rate of leaf area per plant of the pot with 30 cm G.W.T. was the highest through all growth period after fixation of G.W.7., but owing to lower density of leaf, the dry weight of leaves per plant was less rather than that of the pot with 170 cm G.W.T. at 64 days after transplanting. 4. The highest evapotranspiration per plant per day was shown at the 45th day after transplanting in the pots with 30cm and 100cm G.W.T. and at 60 days in the pots with 170cm and 230cm G.W.T respectively. 5. In the soil moisture conditions with 30cm and 100cm G.W.T., evapotranspiration per plant per hour was much higher in the daytime that at night as well as in clear day than in rain-cloudy day owing to loner relative humidity , but in the water stress condition with 230 cm G.W.T., that was much lower. 6. Total evapotranspiration per plant during the whole growing period of 64 days was in order of 30cm > 100 cm > 170 cm > 230 cm G.W.T.. Total evapotranspiration for 34 days after fixation of G.W.T was much higher at night than in the daytime in case of water stress conditions i.e 170cm and 230cm G.W.T. but in normal condition of the pots with 30cm and 100cm G.W.T. that was much higher in the daytime than at night. 7. Leaf water potential of the 3rd and 6th leaf from top at 64 days after transplanting was in order of 100cm > 30 cm > 170cm > 230cm G.W.T. The reason why leaf water potential in the pot with 30cm was less than that in the pot with 100cm G.W.T. would be the abnormal turgidity with low density of cell substrates by the excess water absorption in the pot with 30cm G.W.T..

• Korean Journal of Weed Science
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• v.10 no.2
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• pp.109-113
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• 1990

In order to determine selective mode of action of naproanilide between rice and paddy weeds, absorption and translocation of $^{14}C$-naproanilide in rice, Echinochloa crus galli, Cyperus serotinus, and Sagittaria pygmaea were studied, Rice plant and Echinochloa crus-galli absorbed less amount of $^{14}C$-naproanilide than Sagittaria pygmaeo and Cyperus serotinus. Less amount of $^{14}C$-naproanilide was translocated into shoots and translocation rate was slower in rice and Ecl:inochloa crzis-galli than that of Sagittaria pygmaea and Cyperars serotinus. Also, 30-40% of $^{14}C$-naproanilide was distributed at tubers of Sagittaria pygmaea and Cyperus serotinus, which explained that higher amount of $^{14}C$-naproanilide was absorbed from tubers. $^{14}C$-naproanilide was gradually decreased in all plant species and finally more radioactivity was determined in Sagittaria pygmaea and Cyperus serotinus than in Echinochloa cars-galli and rice plant after $^{14}C$-naproanilide treated plants were transferred to Kasugai solution.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.522-526
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• 2010

Heat storage application techniques can be categorized into the sensible heat storage and the latent heat storage according to the method of heat storage. Heat storage is the way of saving remaining heat when heating and cooling loads are light, and then using it when the heating and cooling loads are heavy. Latent heat storage is defined as the method of saving heat by using substances which have high potential heat when phase change is in the range of a certain temperature and when heat storage space is small, compared to those of sensible heat storage and it is possible that absorption and emission of heat at a certain temperature. This study is conducted to save energy when either air-conditioning or heating is operated in a building. We have tried to find out the essential properties of matter and the optimum mixing rate about cement and gypsum for building materials, which have been widely used for proper phase change materials (PCM), when thermal environment property is applied. So we obtained the result of the cooling delay effect about 19% with heat storage mortar containing 3 wt% of PCM.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.305-309
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• 1994

Precooked powder of redbean porridge (RP) was prepared by the series of process extrusion, drying, milling and blending with a mixture of whole redbean flour and corn starch and others. The optimum process and quality of products for RP were investigated. After extrusion under the moisture content 24 to 26%, twin screw speed 350 rpm, extrusion temperature 150 to $155^{\circ}C$ and feed rate 60 kg/hr, the product had a higher quality with its natural redbean flavor/color. During the extrusion process, extrusion temperature and specific mechanical energy increased from 150 to $198^{\circ}C$ and from 134 to 144 kwh/ton respectively, as the amount of addition water decreased from 6 to 2 kg/hr. By the hot air drying of redbean extrudate (RE). it could be dried below to 4% moisture content, of which level considered as an optimal moisture content for anti-caking of the powdered product, at $80^{\circ}C$ for 4hrs and at $100^{\circ}C$ for 1.5 hrs respectively. In the sieve analysis of extrudate powder, when the product milled through a mesh size of 0.5 mm or 1.0 mm, about 80% or 65% of the feed was passed a 65 mesh screen respectively. Moisture absorption of final blended products was formed a cake under 100% of relative humidity after 13 hrs of storage. As the amount of RE powder reduced, the flavor score of products decreased by sensory evaluation of products prepared by the different ratio of RE powder, corn starch and sugar.