• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.233-243
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• 2013

The inorganic pearlescent pigment have high physical and chemical stability, thus it is used in a variety field, which has better light stability, solvent resistance and thermostability. In this paper, we were synthesized the pearlescent pigment for cosmetics which was coated cobalt chloride for base of blue color metal oxide on mica titania substrate using hydrothermal synthesis method. To complement the color of the pigment by cobalt, pearl pigment were coated by different metal salt and cobalt ratio, to implement a variety of color value, depending on the kind of metal salts were synthesized. Synthesized pearlescent pigments appear various color as kind of added metal salt precursor and molar ration of cobalt and other metals. We controlled coating and color by composition of metal salt and type of metal salts, and that confirm the pigment characteristics of color changes through the analysis of color difference meter. Synthesized pigment was characterized by SPM, SEM, XRD, and EDS.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.132-145
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• 2009

Faults in rock mass have strong influences on the behaviors of rock structure such as rock slope, tunnel and underground space. Thus, it is very important to analyse for the characteristics of fault rocks in design for tunnel. But, due to the limitation of geotechnical investigation in design stages, tunnel engineers have to carry out the face mapping and additional geological survey during tunnel excavation to find the distribution of faults and the engineering properties of faults for support and reinforcement design of tunnel. In this study, various geological survey and field tests were carried out to analyse the characteristics of the large thrust fault zone through the large sectional tunnel is constructed in mica-schist region. Also, the distribution of structural geology, the shape of thrust faults and the mechanical properties of fault rock were studied for the reasonable design of the reinforcement and support method for the highly fractured fault zone in the large-span tunnel.

• Journal of the Korean Society of Radiology
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• v.1 no.1
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• pp.39-44
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• 2007

In this study, wireless measurement technique for human motion was developed to monitor movement disorder patients during their daily life. MICA, TinyOS, and nesC, developed by UC Berkeley, were used as wireless sensor, its software platform, and programming language. The human motion data, generated by two axial accelerometer(ADXL202) was transmitted to PDA(iPaq3630) by 916Mhz short range communication chip(TR1000). It could be stored at PDA by simple Windows CE programming. To test the developed device, it was attached at human chest and the acquired data was shown as a graph during his motion of sitting, standing, and lying. The result showed that human motion could be logged without any hooking and constraints. Therefore, this device can be used to monitor patient's movement disorder and activity of daily life(ADL).

• Economic and Environmental Geology
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• v.23 no.4
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• pp.453-463
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• 1990

The Yechon shear zone developed by strike-slip movement was formed in a relatively high temperature condition just after the Jurassic syntectonic granites had been emplaced during Daebo Orogeny. Post-emplacement formation of the shear zone is favored by continuity of foliations and lineations within and without the granites, development of mylonitic structures in the wallrocks, deformation of pegmatite and felsite dikes, and pretectonic growth of porphyroblasts in the wallrocks. A variety of shear sense indicators in the shear zone are predominantly observed in the intensely to extremely deformed rocks. They show that bulk non-coaxial detormation has occurred, and that the sense of shear is consistently dextral with S-C fabrics, grain shape fabrics, asymmetric porphyroclast systems, mica fish, asymmetric extension structures and quartz C-axis fabrics.

• Journal of Industrial Technology
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• v.9
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• pp.29-41
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• 1989

A general study on the upgrading of mica minerals which are mainly found in pegmatite deposits was carried out for the purpose of developing a technique for recovering mica in form of comercial grade products. By the way the grade one of about 5~6% $K_2O$ still is not developed. The target of this research work is to be establish a process for the efficient concentration of muscovite, containing more than 10% $K_2O$. The tests are applied to incraese the recovery and grade of concentrates in term of variations of conditions. The test sample consists of mainly muscovite and gangue mineral such as quartz, pyrite and chlorite. Decantation and shaking table tests were ineffective to up-grade this low grade one, but flotation method gave satisfactory result. By means of grade one, but flotation method gave satisfactory result. By means of grindability tests, an optimum result could be obtained from the sample ground to -48mesh feed size. The flotation result indicates that the dodecyl ammonium chloride used as a cationic collector is effective on the negatively charged surface, while the sodium dodecyl sulfate as an anionic collector is effective on the positively charged surface. Muscovite was floated by petroleum sulfonate as well as amine type collector, it also floated by MIBC as well as pine oil frother under well condition. Fine muscovite concentrates of about 10.68% $K_2O$ was obtained with 22.4% yield, by decantation, the muscovite concentrates of 10.10% $K_2O$ was obtained with 23.54% yield, by table concentration, the muscovite concentrates of 11.51% $K_2O$ was obtained with 23.0% yield by flotation.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.4
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• pp.284-289
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• 2014

Farmers in highlands in South Korea pile up 20 to 30 cm of saprolites, mostly granite- or granite-gneiss-weathered materials, on surface of arable lands every three to five years to compensate eroded soil and sometimes to discontinue soil-borne diseases. Immediate increases of infiltration and percolation rates are expected with coarse textured saprolites while soil drainage becomes poorer in a long-term. In this study, we analyzed mineralogical characteristics and micro-morphology of plow pan to investigate processes making impermeable layers. Soil samples were collected from plow pan, usually located at approximately 20 cm soil depth and at the lower part of piled saprolites, in arable lands in Hoenggye 5-ri, Daekwanryeong-myeon, Gangwon-do (N37.7, E128.7) in which saprolites were added 2, 4, and 8 years ago; saprolites were transported from similar areas. The saturated hydraulic conductivity decreased over time. Based on soil thin section pedography, quartz and feldspar accounted for a majority of minerals. The size of feldspar decreased and macropores became filled with clay or silt particles over time, which implies that macropores were packed with particles weathered from feldspar. The X-ray diffraction (XRD) analysis indicated that intensity of feldspar decreased over time and the reverse was true for kaolinite and illite, indicating that feldspar and mica weathering induced formation of kaolinite and illite. Conclusively, deteriorated drainage by formation of impermeable layers in farms with piled saprolites was caused by accumulation of clay minerals such as kaolinite and illite in macropores; illite and kaolinite can be formed by weathering of mica and feldspar, respectively.

• Geosciences Journal
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• v.22 no.6
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• pp.1001-1013
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• 2018

A new type of uranium occurrence in Korea was identified in pegmatitic and hydrothermally altered granite in the Daejeon area. The U-bearing parts typically include muscovite, pink-feldspar and sericite as alteration minerals. In this study, the geochemical characteristics and alteration age of the granitic rocks were examined to provide evidence for hydrothermally-enriched uranium. The K-Ar ages of muscovite coexisting with U-bearing minerals were determined as 123 and 128 Ma. The U-bearing rocks have relatively low ($CaO+Na_2O$), high $K_2O$ contents, and high alteration index values by major element geochemistry. The trace element geochemistry shows that the uraniferous rocks have significantly low Th/U ratios and strongly differentiated features. The rare earth element patterns indicate that the uraniferous rocks have a low total REE and LREE contents with depletion of Eu. Considering the geochemical variation of the granitic rock major, trace and rare earth elements, it can be concluded that uranium enrichment in pegmatites and altered granite should be genetically related to post-magmatic hydrothermal alteration of K-metasomatism after emplacement of the two-mica granite. This is the first report for geochemical characteristics of Mesozoic granite-related U-occurrences in South Korea. This study will help further research for uranium deposits with similarities in geological setting, mineralogy and age data between South China and Korea, and can also be expected to help solve the source problems related to high uranium concentrations in some groundwater occurring in the granitic terrane.

• Polymer(Korea)
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• v.34 no.4
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• pp.352-356
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• 2010

The effects of the filler shapes and contents on the coefficient of thermal expansion (CTE) for polypropylene (PP) composites which included three dimensional ellipsoids ($a_1>a_2>a_3$), as determined by two aspect ratios (${\rho}_\alpha=a_1/a_3$ and ${\rho}_\beta=a_1/a_2$) were analyzed by the theoretical approach proposed by Lee and Paul and compared with the experimental results. The shapes of fillers in the composites were various, such as spherical, fiber, disc, and ellipsoid, using barium sulfate, glass fiber, and mica. The longitudinal CTE of barium sulfate whose shape was sphere ($\rho_\alpha=\rho_\beta=1$) decreased. For the glass fiber, primary aspect ratio decreased with the filler content, and longitudinal CTE decreased as filler contents increased. Normal CTE initially increased in the lower filler content. For the mica, longitudinal and transverse CTE decreased but normal CTE increased in the lower filler content like predicted values.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.3-16
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• 2008

A Wireless Sensor Network (WSN for short) is a wireless network consisting of distributed small devices which are called sensor nodes or motes. Recently, there has been an extensive research on WSN and also on its security. For secure storage and secure transmission of the sensed information, sensor nodes should be equipped with cryptographic algorithms. Moreover, these algorithms should be efficiently implemented since sensor nodes are highly resource-constrained devices. There are already some existing algorithms applicable to sensor nodes, including public key ciphers such as TinyECC and standard block ciphers such as AES. Stream ciphers, however, are still to be analyzed, since they were only recently standardized in the eSTREAM project. In this paper, we implement over the MicaZ platform nine software-based stream ciphers out of the ten in the second and final phases of the eSTREAM project, and we evaluate their performance. Especially, we apply several optimization techniques to six ciphers including SOSEMANUK, Salsa20 and Rabbit, which have survived after the final phase of the eSTREAM project. We also present the implementation results of hardware-oriented stream ciphers and AES-CFB fur reference. According to our experiment, the encryption speeds of these software-based stream ciphers are in the range of 31-406Kbps, thus most of these ciphers are fairly acceptable fur sensor nodes. In particular, the survivors, SOSEMANUK, Salsa20 and Rabbit, show the throughputs of 406Kbps, 176Kbps and 121Kbps using 70KB, 14KB and 22KB of ROM and 2811B, 799B and 755B of RAM, respectively. From the viewpoint of encryption speed, the performances of these ciphers are much better than that of the software-based AES, which shows the speed of 106Kbps.

• Journal of Life Science
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• v.33 no.2
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• pp.149-157
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• 2023

Transforming growth factor-β (TGF-β) is a multifunctional cytokine that affects not only the survival and growth of cancer cells but also the activity of immune cells. Although it has been generally accepted that cancer cell-derived TGF-β could promote the survival and growth of early cancer cells and have immunosuppressive roles, it has been known that TGF-β has differential effects according to the type or stage of cancer cells. Therefore, it is hard to clearly define its role in cancer progression and immune responses. This study investigated the effects of TGF-β signaling on the expression of five NKG2D ligands and the NK cell-mediated anticancer immune response in the primary colon cancer cell line KM12C and its two metastatic cell lines, KM12SM and KM12L4A. At the surface protein level, exogenous TGF-β decreased the expression of MICA, MICB, ULBP1, and ULBP2, and galunisertib increased the expression of MICA, MIAB, ULBP1, ULBP2, and ULBP3 in KM12C. However, KM12SM and KM12L4A showed no significant changes in the expression of NKG2DLs after treatment with TGF-β or galunisertib. TGF-β signaling inhibition via galunisertib improved the NK cell-mediated anticancer immune response against KM12C but did not show a significant response to KM12SM and KM12L4A. Therefore, the suppression of TGF-β signaling could improve the NK cell-mediated anticancer immune response against KM12C. However, an increase in NKG2DLs expression and an enhanced NK cell-mediated cancer immune response is hard to expect due to the alteration of TGF-β signaling in KM12SM and KM12L4A.