• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.719-724
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• 2015

Isoliquiritigenin (ILG) is a hydrophobic component in licorice and has a variety of pharmaceutical and biological activities. In this study, we prepared an isoliquiritigenin-hydroxypropyl-${\beta}$-cyclodextrin (ILG/HP-${\beta}$-CD) complex by freeze-drying method to enhance its water solubility. The complex was characterized by phase solubility studies, DSC, SEM, and 1H NMR. Antimicrobial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were evaluated by broth dilution method. The results showed that the stoichiometry of ILG/HP-${\beta}$-CD complex was 1 : 1. The antimicrobial activity of ILG/HP-${\beta}$-CD complex was higher than that of using free ILG against S. aureus and E. coli. Therefore, we suggest that ILG/HP-${\beta}$-CD complex may be used as a natural antiseptic and could potentially replace synthetic preservatives in cosmetic and food industries.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.93-107
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• 2013

Thermal conduction of the particulate composites or granular materials can be widely used in porous materials and geotechnical engineering. And it has continued to develop "effective thermal conductivity" of medium by modeling energy relationship among particles in medium. This study focuses on the development of the effective thermal conductivity at the unsaturated conditions of soils using the modified network model approach assisted by synthetic 3D random packed systems (DEM method, Discrete Element Method) at the particle scale. To verify the network model, three kinds of glass beads and the Jumunjin sand are used to obtain experimental values at various unsaturated conditions. The PPE (Pressure Plate Extractor) test is then performed to obtain SWCC (Soil-Water Characteristic Curve) of soil samples. In the modified network model, SWCC is used to adjust the equivalent radius of thermal cylinder at contact area between particles. And cutoff range parameter to define the effective zone is also adjusted according to the SWCC at given conditions. From a series of laboratory tests and the proposed network model, the modified network model which adopts a SWCC shows a good agreement in modeling thermal conductivity of granular soils at given conditions. And an empirical correlation between the fraction of the mean radius (${\chi}$) and thermal conductivity at given saturated condition is provided, which can be used to expect thermal conductivity of the granular soils, to estimate thermal conductivity of granular soils.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.78-84
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• 2015

The purpose of this study is to evaluate the removal efficiency of phosphorus from synthetic waste water by reduction and oxidation reaction of Cu-Zn metal alloy. Cu-Zn metal alloy applied in this study is composed of 40% of Zn and 60% of Cu, which is so called Muntz metal. And the fibrous type of metal alloy has approximately $200{\mu}m$ of thickness. Metal is oxidized in an aqueous solution to generate electron and metal ion. The mechanism of phosphate treatment is co-precipitation of metal ion and phosphorous ion at various pH and temperature. The treatment efficiency showed the maximum at a one cycle treatment. This result means that the surface area of reaction material is sufficient enough to get reaction equilibrium. Experiment is conducted at various pH from 5 to 9, and showed the maximum efficiency at pH 8. Phosphorous is dominated as a type of $H_2PO_4{^-}$ and $HPO_4{^{2-}}$ at this pH condition. We could not consider the temperature effect independently, because phosphorous removal efficiency showed such a complex mechanism. We could get high efficiency at lower temperature in this research.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.79-90
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• 2017

Urban environment represent one of the most dynamic regions on earth. As in other countries, forests, green areas, agricultural lands are rapidly changing into residential or industrial areas in South Korea. Monitoring such rapid changes in land use requires rapid data acquisition, and satellite imagery can be an effective method to this demand. In general, SAR(Synthetic Aperture Radar) satellites acquire images with an active system, so the brightness of the image is determined by the surface roughness. Therefore, the water areas appears dark due to low reflection intensity, In the residential area where the artificial structures are distributed, the brightness value is higher than other areas due to the strong reflection intensity. If we use these characteristics of SAR images, settlement areas can be extracted efficiently. In this study, extraction of settlement areas was performed using TerraSAR-X of German high-resolution X-band SAR satellite and KOMPSAT-5 of South Korea, and object-oriented image classification method using the image segmentation technique is applied for extraction. In addition, to improve the accuracy of image segmentation, the speckle divergence was first calculated to adjust the reflection intensity of settlement areas. In order to evaluate the accuracy of the two satellite images, settlement areas are classified by applying a pixel-based K-means image classification method. As a result, in the case of TerraSAR-X, the accuracy of the object-oriented image classification technique was 88.5%, that of the pixel-based image classification was 75.9%, and that of KOMPSAT-5 was 87.3% and 74.4%, respectively.

• Ocean and Polar Research
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• v.25 no.3
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• pp.277-286
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• 2003

Nitrification performance of fixed film biofilters using coarse sand, loess bead, or styrofoam beads in biofilter columns 1 meter high and 30cm in diameter were studied at different hydraulic and organic matter loading rates. Synthetic wastewater was supplied to the culture tank in order to maintain desired TAN concentrations in inlet water to biofilters. All the biofilters were conditioned 5 months before start of sampling. TAN and $NO_2-N$ conversion rates increased with an increase in the hydraulic loading rate (HLR). However, the improvement in biofilter performance was not linearly correlated to HLR in styrofoam bead filters. This is mainly due to the characteristics of the styrofoam beads used. TAN conversion rates of sand filters increased with the increase of HLR up to $200m^3/m^2$. per day. No increase in the TAN conversion rate was observed at the highest HLR since flooding on the media surface took place. HLR had a significant impact on the TAN conversion rates in loess bead filter up to the highest HLR tested (P<0.05). TAN conversion rates were much less at organic matter loading rates of 9 and 18kg $O_2/m^3$ per day than those without the addition of organic matter in styrofoam bead filters. The addition of glucose resulted in a reduction of the TAN conversion rate from 540 to 284g $TAN/m^3$ per day. No significant difference of TAN conversion rates between the two organic matter loading rates was found (p<0.05). This indicates that the impact of organic matter on nitrification becomes less and less sensitive with an increase in the COD/TAN ratio. At an organic matter loading rate of 9kg $O_2/m^3$. per day, a great reduction of TAN conversion rates was observed in sand filters and loess bead filters. Clearly, organic matter can be one of the most Important Impacting factors on nitrification. $NO_2-N$ conversion rates showed a similar trend for TAN. Based on the TAN and nitrite conversion rates, styrofoam beads showed the best performance among the three filter media tested. Also, the low gravity and price of styrofoam beads make the handling easier and more cost-effective for commercial application. The results obtained at the highest organic matter loading rates can be used in the biofilter design in recirculating aquaculture system.

• Journal of Korean society of Dental Hygiene
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• v.8 no.3
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• pp.85-98
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• 2008

This study is to enforce to ready basic data of effective dental education program and no smoking and no drinking program for high school students who do smoking and drinking, executed investigation by own recording way using smoking and questionnaire consisted of actual conditions and caries prevention awareness and dental health knowledge degree of drinking to some man high school. Analyzes result that total 487 people respond in SPSS WIN 13.0 programs and got following sequence. Result of this study is as following. 1. Mans high school students had more students who do not than a drinking student and main current received most soju. Third-year student appeared by thing which receive a lot of soju than 1 or 2 class student but different other difference was not seen by class. 2. Mans high school students had more students who do not than a smoking student and a student who smoke more than 3 years was the most. I can know was old since third-year student smokes than 1 or 2 class student. 3. It was not difference that keep in mind by drinking, smoking availability although there were many students who recognize that all of the on-time dental medical examination, sugar intake limitation, fluorine inclusion toothpaste, teeth fluorine application are seldom effective on caries prevention. 4. Recognized that right brushing is effective relatively on caries prevention. I was shown difference that recognized that righter brushing is effective on bad tooth courtesy call than a student who a student who do not smoke does, and keeps in mind according to smoking availability ($x^2$=6.78, p<0.05). 5. I knew best about question of 'A caries may not treat if is painless' among that question ask knowledge for a caries, and appeared by thing which do not know best about question of 'Know that method that supply fluorine in water'. 6. A student who do not drink general dental know-how for a caries was high knowledge degree for a caries than a drunk student but it was no difference that keep in mind by drinking availability. Also, a student who do not smoke by smoking availability was high knowledge degree for a caries than a done student but difference that keep in mind statistically was not seen. 7. It was no difference that keep in mind by drinking availability, but a student who do not smoke by smoking availability was high relation knowledge degree with food and a caries than a smoked student, and I was shown difference that keep in mind according to smoking availability(t=-2.03, p<0.05). 8. Awareness and synthetic estimation degree of knowledge degree a student who do not smoke than a smoked student mouth knowledge degree high, and I was shown difference that keep in mind according to smoking availability(t=-2.03, p<0.05). When see as result such as singularity, family, school, all social institutions may have to help by national business coming and try so that can become national business based on special know-how for development of effective and epoch-making education program as quickly as possible.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.544-553
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• 2018

This study was conducted to determine the effects of breed and sex on meat quality and sensory properties of the loin in three-way crossbred pigs: $Landrace{\times}Yorkshire{\times}Duroc$ (LYD) and $Landrace{\times}Yorkshire{\times}Woori$ (LYW) black pig synthesized by Korean native breed. Carcass traits did not differ by breed. Carcass weight and backfat thickness were higher in castrates than in gilts (p<0.01). LYW showed significant high values in fat content, cooking loss, and water-holding capacity (WHC) than LYD (p<0.05). Redness and yellowness of the meat were higher in LYW than in LYD (p<0.01). Further, LYW had lower pH and shear force than LYD (p<0.001). Significant high scores in color and flavor were obtained in LYW or gilts compared to LYD or castrates by sensory panel, respectively (p<0.05). However, other sensory traits did not differ by breed or sex. Capric acid (C10:0) was higher in LYD than LYW (p<0.001). However, stearic acid (C18:0) and saturated fatty acid (SFA) contents were higher in LYW than LYD (p<0.05). Eicosenoic acid (C20:2) and the n6/n3 ratio were higher in gilts than in castrates, whereas SFA content was higher in castrates than in gilts. These results suggest that certain physicochemical qualities of meat and sensory properties are improved in LYW compared to LYD. This study could provide basic data on meat quality of crossbred pigs with Woori black pig as a terminal sire.

• Membrane Journal
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• v.16 no.3
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• pp.221-229
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• 2006

This study is about the preparation and characterization of sulfonated random copolymer membranes containing perfluorocyclobutane (PFCB), fluorenyl, and sulfonyl units. The polymers were prepared through three synthetic steps, that is, the synthesis of a trofluorovinylether-terminated monomer, its thermal polymerization, and post-sulfonation using chlorosulfonic acid. A series of sulfonated random copolymers with different ion exchange capacity (IEC) were prepared by changing contents of fluorenyl uints in polymers with fixed molar ratio of chlorosulfonic acid during the post-sulfonation reaction. All the synthesized compounds were characterized by FT-lR, $^1H-NMR$, $^{19}F-NMR$, and Mass spectroscopy. As the content of sulfonated fluorenyl units increased, the IEC, water uptake, and ion conductivity of the sulfonated random copolymer membranes increased. The sulfonated random copolymer S-1 and S-2 showed higher values of ion conductivity than the Nafion-115 in a wide range of temperatures ($25{\sim}80^{\circ}C$).

• Applied Microscopy
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• v.42 no.2
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• pp.67-76
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• 2012

The biomimetic approach on the cuticular spinning nozzles of the major ampullate silk glands in the golden-web spider Nephila calvata has been attempted using various visualizing techniques of light and electron microscopes to improve the design of spinning nozzle for producing synthetic nanofibers spun from electrospinning apparatus. The major ampullate spigot which has the most effective nozzle system to produce nanofibers for dragline silk with high strength and elasticity is connected via the bullet type spigot on anterior spinneret with flexible terminal segment. The excretory duct which transports the liquid silk feedstock from ampulla to spigot is divided into 3 limbs by loops back on itself to form an S-shape morphology that is bundled in connective tissue. Final diameter of the nanofibers at nozzle was dramatically reduced by gradual narrowing of duct cuticle less than 10 times comparing to its original size of funnel region. Moreover, the funnel has a characteristic cuticular organization with porous microstructure which seems to be related to water removal from feedstock of silk precursors. High magnification electron micrographs also reveal the presence of the spiral grooves on the surface of the cuticular intima near the valve which presumed to reduce friction during rapid flow of liquid silk.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.221-230
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• 1999

A new technique for the preparation of porous polyurethane vascular prostheses was investigated. Synthetic vascular grafts with porous wall have been widely proposed, claiming that strength, suture retention, kink resistance, and other handling properties are improved over those with nonporous solid wall. Related to these facts, the control of pores and compliance match have been very important and interesting issues. Two kinds of polymer sheets were compared. One was the porous PU-sheet made at room temerature by the solvent/non-solvent exchange. And the other was the porous PU-sheet fabricated by thermal phase transition and solvent/non-solvent exchange in the thermal controlled bath. According to the result of the above experiments, polyurethane solution was injected into a mold designed for U-type graft. After freezing at low temperature, solvent was dissolved out with alcohol at < $0^{\circ}C$ and water at room temperature to form porous vessels. The average pore size and pore occupation were easily changed by changing polyurethane concentration and freezing rate. This technique can give a proper pore size for tissue ingrowth, and suitable compliances for matching with arteries and veins. In addition, the fabrication of more complicated shaped vessels such as the U-type vascular grafts is easily controlled by using a mold. This method might give a desired compliact graft for artificial implantaion with the commercially available medical polymers.