• Textile Coloration and Finishing
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• v.28 no.1
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• pp.48-56
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• 2016

Improvement of heat sink technology related to the continuous implementation performance and extension of device-life in circumstance of easy heating and more compact space has been becoming more important issue as multi-functional integration and miniaturization trend of electronic gadgets and products has been generalized. In this study, it purposed to minimize of decline of the heat diffusivity by gluing polymer through compounding of inorganic particles which have thermal conductive properties. We used NH-9300 as base resin and used inorganic fillers such as silicon carbide(SiC), aluminum nitride(AlN), and boron nitride(BN) to improve heat diffusivity. After making film which was made from 100 part of acrylic resin mixed hardener(1.0 part more or less) with inorganic particles. The film was matured at $80^{\circ}C$ for 24h. Diffusivity were tested according to sorts of particles and density of particles as well as size and structure of particle to improve the effect of heat sink in view of morphology assessing diffusivity by LFA(Netzsch/LFA 447 Nano Flash) and adhesion strength by UTM(Universal Testing Machine). The correlation between diffusivity of pure inorganic particles and composite as well as the relation between density and morphology of inorganic particles has been studied. The study related morphology showed that globular type had superior diffusivity at low density of 25% but on the contarary globular type was inferior to non-globular type at high density of 80%.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.52.1-52.8
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• 2019

Background: A compact passive oxide layer can grow on tantalum (Ta). It has been reported that this oxide layer can facilitate bone ingrowth in vivo though the development of bone-like apatite, which promotes hard and soft tissue adhesion. Thus, Ta surface treatment on facial implant materials may improve the tissue response, which could result in less fibrotic encapsulation and make the implant more stable on the bone surface. The purposes of this study were to verify whether surface treatment of facial implant materials using Ta can improve the biohistobiological response and to determine the possibility of potential clinical applications. Methods: Two different and commonly used implant materials, silicone and expanded polytetrafluoroethylene (ePTFE), were treated via Ta ion implantation using a Ta sputtering gun. Ta-treated samples were compared with untreated samples using in vitro and in vivo evaluations. Osteoblast (MG-63) and fibroblast (NIH3T3) cell viability with the Ta-treated implant material was assessed, and the tissue response was observed by placing the implants over the rat calvarium (n = 48) for two different lengths of time. Foreign body and inflammatory reactions were observed, and soft tissue thickness between the calvarium and the implant as well as the bone response was measured. Results: The treatment of facial implant materials using Ta showed a tendency toward increased fibroblast and osteoblast viability, although this result was not statistically significant. During the in vivo study, both Ta-treated and untreated implants showed similar foreign body reactions. However, the Ta-treated implant materials (silicone and ePTFE) showed a tendency toward better histological features: lower soft tissue thickness between the implant and the underlying calvarium as well as an increase in new bone activity. Conclusion: Ta surface treatment using ion implantation on silicone and ePTFE facial implant materials showed the possibility of reducing soft tissue intervention between the calvarium and the implant to make the implant more stable on the bone surface. Although no statistically significant improvement was observed, Ta treatment revealed a tendency toward an improved biohistological response of silicone and ePTFE facial implants. Conclusively, tantalum treatment is beneficial and has the potential for clinical applications.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.479-487
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• 2015

The thallium-doped sodium iodide [NaI(Tl)] scintillation detector is preferred as a gamma spectrometer in many fields because of its general advantages. A silicon photomultiplier (SiPM) has recently been developed and its application area has been expanded as an alternative to photomultiplier tubes (PMTs). It has merits such as a low operating voltage, compact size, cheap production cost, and magnetic resonance compatibility. In this study, an array of SiPMs is used to develop an NaI(Tl) gamma spectrometer. To maintain detection efficiency, a commercial NaI(Tl) $2^{\prime}{\times}2^{\prime}$ scintillator is used, and a light guide is used for the transport and collection of generated photons from the scintillator to the SiPMs without loss. The test light guides were fabricated with polymethyl methacrylate and reflective materials. The gamma spectrometer systems were set up and included light guides. Through a series of measurements, the characteristics of the light guides and the proposed gamma spectrometer were evaluated. Simulation of the light collection was accomplished using the DETECT 97 code (A. Levin, E. Hoskinson, and C. Moison, University of Michigan, USA) to analyze the measurement results. The system, which included SiPMs and the light guide, achieved 14.11% full width at half maximum energy resolution at 662 keV.

• Journal of KIISE
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• v.42 no.4
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• pp.496-503
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• 2015

Most programming languages are designed based on English. It becomes another barrier in learning programming languages in non-English speaking country. If a programming language is presented using a native language, the education cost of programming will be much cheaper and the programming itself can be much more fun. However, designing the programming languages based on native languages has not been much focused or published up to now. It is partly because the evolution of popular programming languages is so fast, and partly because the efficiency of programs is much stressed than the source code. But, the designing of programming languages based on native language is not a small issue, especially if we reflect on the education of programming. In fact, there have been significant efforts reported in the Korean programming languages so far, but it has not practically been used in the education. This paper introduces yet another Korean programming language, namely Sprout, which is concise and can be easily learned by beginners. To demonstrate the conciseness of Sprout, we have performed two experiments on Sprout. Firstly, we compared the sizes of the programs in Sprout with those in former Korean programming languages. Secondly, we compared the size of Sprout, the language itself, with those of popular programming languages such as C and Python. According to the experiments, Sprout programs are more concise to 10% on average than those in former Korean languages. Furthermore, Sprout itself is more compact to 24% on average than other popular programming languages.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.1
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• pp.47-68
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• 2006

Purpose : This study was carried out to investigate the effects of Gagamdokhwalgisang-Tang on the morphometric changes of femur, and on the hormones and cytokines associated with bone metabolism in overiectomized rats. Methods : Twenty-four female Sprague-Dawley rats were divided into sham operated group(normal) ovariectomized group(control), and treated with extract of GD group(treated). Each group was evaluated the changes of body weight at 0, 3, 6, 8 weeks after ovariectomy. Morphometric analysis(femur weight, femur/body weight ratio, femur ash weight femur ash/body weight ratio cross sectional area of compact bone and concellous bone of femur) and histopathological examination were performed at 8 weeks after ovariectomy. Estrogen, Alkaline Phosphatase(ALP) and cytokine(Tumor necrosis $factor-{\alpha}$, $Interleukin-l{\beta}$, Inerleukin-6) assay were performed at 8 weeks after ovariectomy. Results : 1. The body weight of control and treated group was significantly increased(p<<0.001) compared with the normal group at 8 weeks. 2. The femur weight and femur/body weight ratio of treated group were significantly increased(p<<0.05, p<<0.01) compared with the control group at 8 weeks. 3. The femur ash weight showed no significantly different changes, but femur ash/body weight ratio of treated group was significantly increased(p<<0.05) compared with the control group at 8 weeks. 4. In the cross sectional area of cancellous bone of femoral body, the treated group was significantly increased(p<<0.001) compared with the control group at 8 weeks. 5. The serum estrogen level of treated group showed no significantly different changes compared with the control group at 8 weeks. 6. The serum ALP activity of treated group was significantly decreased(p<<0.01) compared with the control group at 8 weeks. 7. The serum Tumor necrosis $factor-{\alpha}(TNF-{\alpha})$ level of treated group was significantly decreased(p<<0.05) compared with the control group at 8 weeks. 8. The serum $Interleukin-l{\beta}(IL-1{\beta})$ level of treated group was significantly decreased(n<<0.001) compared with the control group at 8 weeks. 9. The serum Interleukin-6(IL-6) level of treated group was significantly decreased(P<<0.01)compared with the control group at 8 weeks. Conclusion : These results indicate that GD inhibits bone resorption in ovariectomized rats. And the major inhibitory mechanism may be related to the inhibitory effects of GD on the secretion of $TNF-{\alpha}$, $IL-1{\beta}$ and IL-6 in the pathogenesis of osteoporosis in estrogen deficient rats.

• Particle and aerosol research
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• v.10 no.4
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• pp.169-176
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• 2014

Air samples were collected at various altitudes (from 165 to 1153 m) to observe vertical distribution of particulate PAHs concentrations using a very compact and light particle sampling package developed by Eun et al.(2013). TD-GC-MS developed by Hwang et al.(2014) was applied to PAHs analysis for effective analysis of PAHs contained trace amounts in the samples. The ranges of total PAHs concentrations were from 6.95 to $96.0ng\;m^{-3}$ on the ground and from 3.75 to $21.74ng\;m^{-3}$ at high altitude, respectively. All of particulate PAHs concentrations measured on the ground were higher than those measured at high altitude, while, the profile of individual PAH compounds between the ground and high altitude samples were similar. It means the distribution of particulate PAHs concentrations at high altitude were affected by the emission of PAHs emitted from ground.

• Nuclear Engineering and Technology
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• v.47 no.6
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• pp.678-699
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• 2015

Although the harsh space environment imposes many severe challenges to space pioneers, space exploration is a realistic and profitable goal for long-term humanity survival. One of the viable and promising options to overcome the harsh environment of space is nuclear propulsion. Particularly, the Nuclear Thermal Rocket (NTR) is a leading candidate for nearterm human missions to Mars and beyond due to its relatively high thrust and efficiency. Traditional NTR designs use typically high power reactors with fast or epithermal neutron spectrums to simplify core design and to maximize thrust. In parallel there are a series of new NTR designs with lower thrust and higher efficiency, designed to enhance mission versatility and safety through the use of redundant engines (when used in a clustered engine arrangement) for future commercialization. This paper proposes a new NTR design of the second design philosophy, Korea Advanced NUclear Thermal Engine Rocket (KANUTER), for future space applications. The KANUTER consists of an Extremely High Temperature Gas cooled Reactor (EHTGR) utilizing hydrogen propellant, a propulsion system, and an optional electricity generation system to provide propulsion as well as electricity generation. The innovatively small engine has the characteristics of high efficiency, being compact and lightweight, and bimodal capability. The notable characteristics result from the moderated EHTGR design, uniquely utilizing the integrated fuel element with an ultra heat-resistant carbide fuel, an efficient metal hydride moderator, protectively cooling channels and an individual pressure tube in an all-in-one package. The EHTGR can be bimodally operated in a propulsion mode of $100MW_{th}$ and an electricity generation mode of $100MW_{th}$, equipped with a dynamic energy conversion system. To investigate the design features of the new reactor and to estimate referential engine performance, a preliminary design study in terms of neutronics and thermohydraulics was carried out. The result indicates that the innovative design has great potential for high propellant efficiency and thrust-to-weight of engine ratio, compared with the existing NTR designs. However, the build-up of fission products in fuel has a significant impact on the bimodal operation of the moderated reactor such as xenon-induced dead time. This issue can be overcome by building in excess reactivity and control margin for the reactor design.

• Bulletin of the Korean Chemical Society
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• v.16 no.10
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• pp.923-929
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• 1995

Four crystal structures of M3-A (M3Na9-xHx-A, M=Rb or K and x=1 or 0), Rb3Na8H-A(a=12.228(1) Å and R1=0.046), Rb3Na9-A (a=12.258(3) Å and R1=0.058), K3Na8H-A (a=12.257(3) Å and R1=0.048) and K3Na9-A (a=12.257(3) Å and R1=0.052), have been determined by single crystal x-ray diffraction technique in the cubic space group Pm3^m at 21 ℃. In all structures, each unit cell contained three M+ ions all located at one crystallographically distinct position on 8-rings. Rb+ ions are 3.12 and 3.21 Å away respectively from O(1) and O(2) oxygens, about 0.40 Å away from the centers of the 8-rings, and K+ ions are 2.87 and 2.81 Å apart from the corresponding oxygens. These distances are the shortest ones among those previously found for the corresoponding ones. Eight 6-rings per unit cell are occupied by eight Na+ ions, each with a distance of 2.31 Å to three O(3) oxygens. The twelfth cation per unit cell is found as Na+ opposite 4-ring in the large cavities of M3Na9-A and assumed to be H+ for M3Na8H-A. With these noble non-framework cationic arrangements, larger M+ ions preferably on all larger 8-rings and the compact Na+ ions on all 6-rings, the bond angles in the 8-rings of M3-A, 145.1 and 161.0 respectively for (Si,Al)-O(1)-(Si,Al) and (Si,Al)-O(2)-(Si,Al), turned out to be remarkably stable and smaller, by more than 12 to 17°, than the corresponding angles found in the crystal structures of zeolites A with high concentration of M+ ions. It is to achieve these remarkably relaxed 8-rings, the main windows for the passage of gas molecules, with simultaneously maximized cavity volumes that M3-A have been selected as one of the efficient zeolite A systems for gas encapsulation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.261-274
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• 2000

The o/w emulsions were prepared with saccharide surfactants which were sucrose monostearate(S160), sucrose distearate(S110), and POE(20) methyl glucose stearate(SSE20). And for emulsion the oils used were n-hydocarbon, squalane(SQ), liquid paraffin(LP), octylpalmitate(OP), octylstearate(OS), alkyl benzoate(AB), isostearyl benzoate(ISB). The structures of o/w emulsion droplet were investigated by laser light scattering and the fractal dimensions were calculated from light intensity curves. Increasing of concentration, chain length, and nonpolarity of oils, fractal dimensions of emulsion droplets were found greater. In general fiactal dimensions were varied from 1.7 to 2.8 and its structures were fractal But the fractal dimensions of octadecane( $C_{18}$), 50, and LP emulsified with S110 and S160 were varied from 3.0 to 3.2 and its structures were more dense. The overall fractal dimensions of S110 and S160 were varied from 2.1 to 2.6, that of SSE20 were varied from 1.5 to 2.1. So it was found that the structures of SSE20 system were less compact than that of S110 and S 160 system, because the hindrance effect of polyoxyehtylene group of SSE20 was stronger than that of sucrose of S160. The strucures of emulsion droplets changed according to the nature of emulsifiers and to compositions of oil substances which they contained, and the structures were found similar when the hydophilic moiety of emulsifiers was same.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.16-27
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• 2018

To predict the influence of volcano eruption on agriculture in South Korea we evaluated the dispersal ranges of the volcanic ashes toward the South Korea based on the possibilities of volcano eruption in Mt. Baekdu. The possibilities of volcano eruption in Mt. Baekdu have been still being intensified by the signals including magmatic unrest of the volcano and the frequency of volcanic earthquakes swarm, the horizontal displacement and vertical uplift around the Mt. Baekdu, the temperature rises of hot springs, high ratios of $N_2/O_2$ and $_3He/_4He$ in volcanic gases. The dispersal direction and ranges and the predicted amount of volcanic ash can be significantly influenced by Volcanic Explosivity Index (VEI) and the trend of seasonal wind. The prediction of volcanic ash dispersion by the model showed that the ash cloud extended to Ulleung Island and Japan within 9 hours and 24 hours by the northwestern monsoon wind in winter while the ash cloud extended to northern side by the south-east monsoon wind during June and September. However, the ash cloud may extent to Seoul and southwest coast within 9 hours and 15 hours by northern wind in winter, leading to severe ash deposits over the whole area of South Korea, although the thickness of the ash deposits generally decreases exponentially with increasing distance from a volcano. In case of VEI 7, the ash deposits of Daejeon and Gangneung are $1.31{\times}10^4g\;m^{-2}$ and $1.80{\times}10^5g\;m^{-2}$, respectively. In addition, ash particles may compact close together after they fall to the ground, resulting in increase of the bulk density that can alter the soil physical and chemical properties detrimental to agricultural practices and crop growth.