• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.1
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• pp.38-47
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• 2002

This paper demonstrates a regional analysis of landslide occurrence potential by applying geographic information system to the Kumi City selected as a pilot study area. The estimate criteria related to natural and humane environmental factors which affect landslides were first established. A slope map and a aspect map were extracted from DEM, which was generated from the contour layers of digital topographic maps, and a NDVI vegetation map and a land cover map were obtained through satellite image processing. After the spatial database was constructed, indexes of landslide occurrence potential were computed and then a few landslide-potential areas were extracted by an overlay method. It was ascertained that there are high landslide-potential at areas of about 30% incline, aspects including either south or east at least, adjacent to water areas or pointed end of the water system, in or near fault zones, covered with medium vegetable. For more synthetic and accurate analysis, soil data, forest data, underground water level data, meteorological data and so on should be added to the spatial database.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.50-55
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• 2011

The introduction of doubled haploid (DH) approach into breeding programs has reduced the times and population sizes required for the production of pure lines. We carried out the experiment for development on effective method of producing haploid in wheat. Emasculated spikelets of wheat were pollinated with maize pollen and cultured in the solution containing 40 g/L sucrose and 2,4-D, NAA, 2,4,5-T and dicamba 24 h after pollination, and then incubated until embryo rescue. Fourteen to sixteen days after pollination, the embryos are excised and cultured in half-strength MS basal medium supplemented with 20 g/L sucrose and 1 mg/L NAA. The type of plant growth regulators was found to be most significant in production of haploid plants. The application of synthetic auxins to pollinated florets, stimulates haploid embryo development to a stage where the embryos can be rescued onto nutrient media. The percentage of seeded florets was significantly affected by 100 mg/L 2,4-D, 150 mg/L 2,4,5-T and 50 mg/L dicamba. The percentage of embryos formed was significantly increased by treatment with 2,4-D and 2,4,5-T at 100 mg/L, and dicamba at 50 mg/L, but the treatments with 150 mg/L 2,4-D inhibited embryo development and plant regeneration. The optimum application time of plant growth regulators was 24 hrs after pollination.

• Geophysics and Geophysical Exploration
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• v.1 no.1
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• pp.31-42
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• 1998

Recently crosshole seismic tomography has come to be widely used especially for the civil engineering, because it can provide more detail information than any other surface method, although the resolution of tomogram will be inevitably deteriorated to some extent due to the limited wavefield aperture on the nonuniqueness of traveltime inversion. In addition, our field sites often consist of a high-velocity bed rock overlain by low-velocity rock, sometimes with a contrast of more than 45 percent, and furthermore the bed rock is folded. The first arriving waves can be then the refracted ones that travel along the bed rock surface for some source/receiver distances. Thus, the desirable first arrivals can be easily misread that cause severe distortion of the resulting tomogram, if it is concerned with (straight ray) traveltime inversion procedure. In this case, comparision with synthetic data (forward modeling) is a valuable tool in the interpretation process. Besides, abundant information is contained in the crosshole data. For instance, examination of tube waves can be devoted to detecting discontinuities within the borehole such as breakouts, faults, fractures or shear zones as well as the end of the borehole. Specific frequency characteristics of marine silty mud will help discriminate from other soft rocks. The aim of this paper is to present several strategies to analyze and interpret the crosshole data in order to improve the ability at first to determine the spatial dimensions of interwell anomalies and furthermore to understand the underground structures. To this end, our field data are demonstrated. Possibility of misreading the first arrivals was illustrated. Tube waves were investigated in conjunction with the televiewer images. Use of shot- and receiver gathers was examined to benefit the detectabilities of discontinuities within the borehole.

• Geophysics and Geophysical Exploration
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• v.15 no.3
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• pp.136-143
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• 2012

In this case study, we present the various and consistent processing techniques for the reasonable interpretation of aeromagnetic data. In the processing stage, we especially focused on the three major respects. First, in the low latitude area, severe artifacts are occurred as a result of reduction to the pole technique. To overcome this problem, variable alternative methods were investigated. From the comparison of each technique, we concluded that energy balancing method gives more fruitful result. Second, because of limited a priori information, it is nearly impossible to employ detailed geological survey due to wide and thick spreading of soils in the survey area. So we especially investigated the new techniques such as extracting slope, curvature and aspect information mainly used in GIS field as well as conventional methods. Finally, by using the Euler deconvolution, we extracted the depth information on the magnetic anomalous body. From the synthetic analysis between depth information and previous discussed results, the detailed future survey area was proposed. We think that a series of processing techniques discussed in this study may perform an important role in the domestic and abroad resource development project as a useful guideline.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.330-341
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• 2018

This study was performed to investigate and measure the antimicrobial activity of evergreen woody species extracts on Trichophyton mentagrophytes. To do this, leaves and stems were collected from Wando and Jeju islands, and were used for the extraction with different solvents (i.e., distilled water, 80% ethanol, and 100% methanol), and at different ultrasonic extracting times (i.e., 15, 30, and 45 minutes). The experiment was conducted by using the agar diffusion method. The clear zone was measured after incubating the paper disc containing the plant extract in a bacterial culture medium. The controls were synthetic antimicrobials, methylparaben and phenoxyethanol, at concentrations of 0.4, 1, 2, and 4 mg/disc. Altogether, extracts of 56 out of 64 species used in this study had inhibitory activity, which confirmed their antimicrobial activity against Athlete's foot. Among them, the crude ethanolic extract of Elaeocarpus sylvestris in 45 min showed a zone of inhibition < 20.2 mm, while the clear zone of Actinodaphne lancifolia ethanolic extraction for 30 min was 23.5 mm. Also, Quercus acuta, Dendropanax morbiferus and Daphne odora showed clear zones of 28.0 mm (45 minutes ethanolic extraction), 20.5 mm (45 minutes crude methanolic extraction) and 19.7 mm (45 minutes methanolic extraction), respectively. Thus, these results confirm that the extracts of evergreen woody species have therapeutic potential against Athlete's foot, and suggest that in order to extract adequate amounts of antimicrobial substance from the plant sources, ideal extraction condition has to be considered.

• Membrane Journal
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• v.29 no.1
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• pp.51-60
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• 2019

In order to improve gas separation properties of polymeric membranes which have been widely applied in the industry field, aluminosilicate hollow nanoparticles named as allophanes were synthesized by sol-gel method and formulated in Poly(dimethylsiloxane) (PDMS) matrix to investigate the gas separation properties of PDMS membrane. Transmission electron microscope (TEM), Energy dispersive X-ray analysis (EDX), X-ray diffractometer (XRD), Surface area and pore size analyzer (BET) and Fourier transform infrared spectrophotometer (FTIR) were carried out to characterize the synthetic allophanes. Then the PDMS mixed matrix membranes were prepared by adding different volume fraction of allophanes. To examine the effect of allophanes addition in PDMS matrix using unmodified allophane and modified ones, the gas permeation experiments were performed using oxygen, nitrogen, methane and carbon dioxide. As the volume fraction of modified allophane increased up to 4.05 Vol% the permeability of four test gases through PDMS mixed matrix membranes increased. Also, the selectivity of $O_2/N_2$ and $CO_2/CH_4$ increased with the contents of the modified allophane. Further improvement of gas separation properties of PDMS mixed matrix membranes containing higher volume percent of allophanes can be expected as long as well dispersion of allophanes in PDMS matrix can be achieved for better PDMS membranes.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.676-684
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• 2019

The Pictet-Spengler reactions have widely known for the organic synthesis or biosynthesis of biologically active compounds, tetrahydro-${\beta}$-carbolines. We have developed the simple and efficient synthetic method for the synthesis of ${\beta}$-carbolines in water. Their chemical structures were characterized by nmr and UPLC/MS/QTOF. Calculated masses of compound 1 ($C_{17}H_{17}N_2$ 249.1392), 2 ($C_{17}H_{23}N_2$ 255.1861), 3 ($C_{19}H_{21}N_2O_3$ 325.1552) and 4 ($C_{19}H_{19}N_2O$ 279.1497) were almost identical with the detected masses of compound 1 (249.1315), 2 (255.1789), 3 (325.1460) and 4 (279.1364) respectively. Those synthesized four compounds showed strong antibiotic activity against the common E. coli.

• Korean Journal of Heritage: History & Science
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• v.49 no.4
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• pp.114-125
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• 2016

Lacquer is one of the most widely used natural resin in East Asia since Neolithic Age. As a major ingredient of lacquerware, lacquer is waterproof, insect-proof and rot-proof to be durable and anti-abrasion, generally utilized for mainly painting purpose. According to lacquerware excavated from several sites of Japan and China, lacquerware seems to appear in Neolithic Age. On the other hand in case of excavation research in Korea, lacquerwares are found after the Bronze Age. The initial purpose of lacquer is estimated to be adhesive, regarding the literatures mentioning bitumen(Yeoksceong ), animal glue(Kyeo) and egg alumen(Nanbaek). Especially piece of jar coffin unearthed in Pyeongtaek Daechu-ri site had trace of restoration by lacquer and hemp as an evidence of lacquer for adhesion in Pre-Three Kingdoms period. Since then a trend to restore the broken ceramics with lacquer and decorate with golden foil lasted especially in Joseon Dynasty. In the field of gold plated lacquer method, mother-of-pearl inlaying technique for lacquerware and restoration of buildings, lacquer is still used as adhesive. Due to matter of reversibility lacquer is being avoided for conservation and restoration of cultural heritage. Lacquer as a traditional material for adhesive since ancient times, however, has advantage in adhesion strength and durability. Because synthetic resin adhesive has problem of emission of volatile organic compounds and aging over time, lacquer receives attention recently. On the contrary, by combination adhesive from mixing lacquer and animal glue, already proved the possibility of applicability and chemical modification. A research to utilize lacquer as modern paint or functional material is also conducted continuously also in China and Japan. To put traditional material into practical use and modernize, chemical research from the molecular level of the lacquer is necessary in the near future.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.425-433
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• 2019

In this paper, the RCS analysis of the 10m unmanned surface vehicles was performed, and the factors of RCS increase were analyzed. Modeling techniques by transforming a geometric shape can reduce the RCS area, which can be used to develop stealth unmanned surface vehicles. In order to reduce the RCS, the existing Top Mast part was moved 1m to the tail part, the 5 degree tilt angle was moved below 0.5 m, and additional guided walls were installed to minimize the influence on the center and surrounding corner reflecting structures. As a result of comparing and analyzing the RCS analysis value with the existing model, it can be seen that the reduced countermeasure model is -3.79 dB lower than the existing model for all elevations. In particular, it can be seen that the strong scattering phenomenon is substantially removed in the region except the sacrificial angle region. In addition, it can be seen that in the case of -5m to 2m where the guide wall is added, the reflected signal is improved up to 20 to 40 dB or more, so that it does not appear on the 2D ISAR image. RCS analysis of unmanned surface vehicles explained the process of analyzing and identifying problem location through distance profile analysis and ISAR image analysis.

• Journal of Conservation Science
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• v.35 no.3
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• pp.253-258
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• 2019

The gilt bronze statue, Seated Avalokiteshvara with a Thousand Hands, of the Goryeo dynasty, is the only one in Korea of its kind that has undergone a conservation process for the special exhibition entitled GORYEO: The Glory of Korea. For the conservation treatment, first, a component analysis (XRF) was conducted, and a manufacturing technique (CT) was analyzed. The results of the investigation revealed that the statue was alloyed with Cu, Sn, and Pb ternary bronze. Its surface, except for the detached plating layers, was originally plated using the mercury amalgam method. This statue was assembled after separately casting each part of the body, such as the left and right arms and the wrists, including the hands, with objects. In particular, each wrist was cast and fitted with a metal nail to express each object in the hands more precisely. Inside the statue, there were five iron cores: two for the head, one for the left elbow, one for the right flank, and one for the right waist. For the preservative treatment, natural adhesive agents, including vegetable gelatin and glue (20%), were mixed with alcohol to protect the base metal and adhere to the plating layers. Using synthetic resin (CDK 520+SN-sheet) for the damaged parts, the restored parts could be attached and detached to/from the statue. Eventually, the compositional analysis and conservation treatment left the statue in a stable condition and ready for exhibitions and future studies.