• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.530-538
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• 2003

Samples with the nominal composition, B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+}$$\delta$/ (110 K phase) high $T_{C}$ superconductors containing MgO as an additive were fabricated by a solid-state reaction method. Samples with 5~50 wt％ MgO were sintered at 820~86$0^{\circ}C$ for 24 h. The structural characteristics, critical temperature and grain size of the samples with different MgO contents were analyzed by XRD and SEM. As the MgO content increased, the intensity of MgO peaks and ratio of Bi-2212 phase in superconductors were intensified and the proportion of the phase transition from Bi-2223 to Bi-2212 was increased.d.creased.d.

• The Journal of the Petrological Society of Korea
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• v.23 no.4
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• pp.311-324
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• 2014

The Hongjeom formation of the Pyeongan Supergroup in the Munkyeong coalfield mainly consists of metapsammite and metapelites. Metampelites occur as slate preserving chloritoid+chlorite+muscovite and andalusite+biotite+chlorite+muscovite mineral assemblages. Chloritoid and andalusite occur as porphyroblast, and the matrix composed of fine-grained micas. Metamorphic P-T conditions for these mineral assemblages are $510-520^{\circ}C$ and 3.0-3.5kbar based on P-T pseudosection in $MnO-K_2O-FeO-MgO-Al_2O_3-SiO_2-H_2O(MnKFMASH)$ system and isopleth intersections of Fe/(Fe+Mg) ratios in chloritoid and chlorite. The medium temperature and low pressure metamorphism resulted from a higher geothermal gradient ($40-45^{\circ}C/km$) condition than that of burial metamorphism. The youngest (SHRIMP U-Pb age; ca. 327-310 Ma) detrital zircon grains from the Hongjeom formation display oscillatory zoning and relatively high Th/U ratio (0.60-1.12). Based on the previous sedimentary, paleontological, and geochronological studies in the Taebaeksan basin together with results of this study, we suggest that (1) initial deposition of the Hongjeom formation was contemporaneous with a magmatic activity in the provenance, (2) the Pyeongan Supergroup was deposited in an arc-related basin at an active continental margin during the Carboniferous to Permain, and (3) magmatic activities occurred repetitively in relatively short interval in the active continental margin had continuously supplied sediments to the basin.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.4
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• pp.472-482
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• 2007

This study deals with the design and implementation results for a high-capacity vol-oxidizer that can convert Uranium Dioxide pellets to $U_3O_8$ powder for up to several tens of kg HM/batch. We developed two versions of the $1^{st}$ vol-oxidizer and the $2^{nd}$ vol-oxidizer. Through an experiment with the $1^{st}$ vol-oxidizer, we deduced some problems concerning the design considerations such as the recovery rate of $U_3O_8$, the oxidation time of the Uranium Dioxide pellets, the exothermic reaction, and the powder dispersion. From the analyses of the drawbacks of the $1^{st}$ vol-oxidizer, we devised some novel items such as a folding type mesh, vibrators, and mixing blades. Also, we used the Stokes and Density ratio Eq. to determine the most reasonable flux for preventing a powder dispersion. Compared with the results of the $1^{st}$ vol-oxidizer, we showed that both the permeability of the $U_3O_8$ powders and the oxidation rate of the Uranium Dioxide pellets of the $2^{nd}$ vol-oxidizer were remarkably increased, and the temperature of the reactor was controlled well in spite of an exothermic reaction. Also, the powder was not entirely dispersed through the outlet of the voloxidizer. The experimental results of this work can help in the design of a novel and efficient vol-oxidizer with a higher capacity.

• Electrical & Electronic Materials
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• v.7 no.5
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• pp.403-408
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• 1994

Dielectric and structural properties of $Ba_{1-x}$(Z $n_{1}$3/T $a_{2}$3/) $O_{3}$+1 mol% Mn $O_{2}$ (x=0, 0.01, 0.02, 0.03, 0.04) ceramics was investigated at microwave frequencies. With $Ba_{+2}$ shortage, the sinterability and the unloaded Q( $Q_{u}$) were much improved, and the ordering in B site and the lattice distortion was greatly enhanced and the structure approached the completely ordered structure. $Q_{u}$ was strongly correlated with these factors such as ordering ratio, lattice distortion and sinterability, and had the maximum value of 7500 at x=0.01. The dielectric constant was near 30 and the temperature coefficient of the resonant frequency was 2 ppm/.deg. C at x=0.01.1.1.1.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.2
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• pp.85-89
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• 2006

To research of the improved mechanical properties of materials for spectacle lens cutting, SiC and TiC were used as the main powder. Also, $Al_2O_3$ and $Y_2O_3$ was included as a sintering additive. The weight ratio of the alumina($Al_2O_3$) to yttria($Y_2O_3$) was set to 1:1. The materials for spectacle lens cutting were fabricated by hot-pressing at $1810^{\circ}C$ for 1h and subsequently annealed at $1860^{\circ}C$ for 3, 6 and 12h to initiated grain growth. The longer annealing time is, the bigger the grain size is. The microstructures were observed by scanning electron microscopy (SEM). The SEM images were quantitatively analyzed by image analysis (Image-Pro Plus, Media Cybernetics, Maryland, U.S.A.). Crack deflection by elongated SiC grains was most frequently observed as the dominant toughening mechanism. Crack deflection was generally observed for elongated SiC grains with aspect ratio(AR) > 2.5 and grain thickness < $2.3{\mu}m$. Crack bridging was also observed as one of the operating toughness mechanism.

• Journal of The Korean Astronomical Society
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• v.36 no.1
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• pp.1-12
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• 2003

Nonthermal particles can be produced due to incomplete thermalization at collisionless shocks and further accelerated to very high energies via diffusive shock acceleration. In a previous study we explored the cosmic ray (CR) acceleration at cosmic shocks through numerical simulations of CR modified, quasi-parallel shocks in 1D plane-parallel geometry with the physical parameters relevant for the shocks emerging in the large scale structure formation of the universe (Kang & Jones 2002). Specifically we considered pancake shocks driven by accretion flows with $U_o = 1500 km\;s^{-l}$ and the preshock gas temperature of $T_o = 10^4 - 10^8K$. In order to consider the CR acceleration at shocks with a broader range of physical properties, in this contribution we present additional simulations with accretion flows with $U_o = 75 - 1500 km\;s^{-l}$ and $T_o = 10^4K$. We also compare the new simulation results with those reported in the previous study. For a given Mach number, shocks with higher speeds accelerate CRs faster with a greater number of particles, since the acceleration time scale is $t_{acc}\;{\propto}\;U_o^{-2}$. However, two shocks with a same Mach number but with different shock speeds evolve qualitatively similarly when the results are presented in terms of diffusion length and time scales. Therefore, the time asymptotic value for the fraction of shock kinetic energy transferred to CRs is mainly controlled by shock Mach number rather than shock speed. Although the CR acceleration efficiency depends weakly on a well-constrained injection parameter, $\epsilon$, and on shock speed for low shock Mach numbers, the dependence disappears for high shock Mach numbers. We present the 'CR energy ratio', ${\phi}(M_s)$, for a wide range of shock parameters and for $\epsilon$ = 0.2 - 0.3 at terminal time of our simulations. We suggest that these values can be considered as time-asymptotic values for the CR acceleration efficiency, since the time-dependent evolution of CR modified shocks has become approximately self-similar before the terminal time.

• The Journal of Internal Korean Medicine
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• v.28 no.3
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• pp.492-501
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• 2007

Objectives : This study was executed in order to evaluate the effects of electroacupuncture on upper-extremity spasticity control in stroke patients. Methods : Eighteen patients with stroke were enrolled and classified into two groups, the study and control group. The control group did not receive any oriental medical treatment. In the study group, the electroacupuncture points were applied to Kokt'aek (PC3) and $Ch'{\u{o}}ch'{\u{o}}n$ (PC2), Naegwan (PC6) and $Ch'{\u{o}}kt'aek$(LU5) of the affected limb. H-reflexl M-response ratio (HIM ratio), modified Ashworth scale (MAS) and Fugl-Meyer motor function assessment (FMA) were used for evaluation of spasticity control before electroacupuncture, within two hours after electroacupuncture, and at two weeks. Results : In MAS, the study group declined more than the control group. but there was no statisticallysignificant consideration. In H/M ratio. the study group was more efficient than the control group. and spasticity decreased successively during the series in the study group. In FMA, motor function in the study group improved more than in the control group and motor function in the study group increased successively during the series. Conclusions : These results showed that electro acupuncture was a useful method to decrease upper-extremity spasticity in patients with stroke. Further studies are needed to explore more cases and the long-lasting carryover effects on upper-extremity spasticity in electroacupuncture.

• The Korean Society of Law and Medicine
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• v.12 no.2
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• pp.11-61
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• 2011

In dieser Arbeit ist zum ersten allgemeiner $\ddot{U}$berblick auf die Verschuldensprinzip, das grunds$\ddot{a}$tzlich f$\ddot{u}$r die Unfalls-Haftung im Bereich der medizinischen Behandlungsfehler noch immerhin gelten, in aller K$\ddot{u}$rze angef$\ddot{u}$hrt und zugleich in rechtsvergleichender Weise auf die sozialrechtliche Typenentwicklung in Bezug auf die haftungsrechtlich motivierte Entsch$\ddot{a}$digung. Gem$\ddot{a}{\ss}$ dem ${\S}$ 46 Gesetzes zur Abhilfe f$\ddot{u}$r medizinische Besch$\ddot{a}$digungenund auf die Mediation-Schlichtung f$\ddot{u}$r medizinische Streitigkeiten ist die rechtssystematische Bedeutung des Kompensations-Zusicherungsgeschafts als eine Art institutioneller Fremdversorgung zu erfassen. Demzufolge geht es h$\ddot{a}$uptsachlich um die Problematik von tatbest$\ddot{a}$ndlichen Merkmalen der Kompensation im ${\S}$ 46 obigen Gesetzes (unten 1) und im Bezug auf die im voraus von GF-Ministerium bekanntgegebene AO (provisorische Fassung) von 8. 11. 2011. um die Analyse einer Reihe von KHG-Entscheidungen $\ddot{u}$ber $\ddot{a}$rztliche Geburtsbehandlungsfehler (unten 2). Dabei ist noch die Geltungsbereich mit entsprechendem Kompensationssystem in Japan zu vergleichen (unten 3). 1. Der terminologische Sinn von "h$\ddot{o}$here Gewalt" ist sowohl semantisch wie auch juristisch-rechtstechnisch eine negative Vorausaussetzung f$\ddot{u}$r haftbar machende Gef$\ddot{a}$hrdungstatbestand. Nicht nur im Inhalt und Umfang vertr$\ddot{a}$gt dieser Rechtsbegriff sich nicht mit dem anderen tatbest$\ddot{a}$ndlich parallell zu erf$\ddot{u}$llenden Merkmal, also "die Besch$\ddot{a}$digung aus unverschuldeter $\ddot{a}$rztlicher Geburtsvorsorge", weil die jene enger als die diese auf dem Begriffsfeld ist, sondern auch im dogmengeschichtlichen, auch doch rechtstechnichen Sinne ist die Terminologie von "h$\ddot{o}$here Gewalt" ungeeignet, f$\ddot{u}$r den kompensatorischen Tatbetand als ein positives Merkmal, zu sein, statt derer, m. E. sollte der Begriff von "unkontrollierbarer Zuf$\ddot{a}$lligkeit" als L$\ddot{o}$sungsansatz verwendet werden. Dazu ist auch die ratio legis zur institutionellen Einf$\ddot{u}$hrung des obigen Kompensations-Zusicherungsgesch$\ddot{a}$fts, das sich auf die Entsch$\ddot{a}$digung des f$\ddot{u}$r Patienten unertr$\ddot{a}$glichen Verlustes gerichtet, d. h. gerade die Augabe des nachteilsausgleichenden Einstehens f$\ddot{u}$r Ungl$\ddot{u}$ck, nicht f$\ddot{u}$r Unrecht, zu ber$\ddot{u}$cksichtigen. 2. Die Typen der KHG-Entscheidungsf$\ddot{a}$llen im Bereich von Gyn$\ddot{u}$kologie k$\ddot{o}$nnten diagnostisch bzw. therapeutisch im folgenden differenziert sein werden; je nach der Kriterien von der Weise und dem Zeitpunkt zur Geburtshilfe, technischen Behandlungsfehlern beim Geburtsvorgang, und Besorgungsfehlern nach dem Geburt u. dgl. 3. Die japanische verschuldensunabh$\ddot{a}$ngige Kompensation ist eigentlich eine Art institutionelle Vorsorge, die anders als koreanische Versorgungssystem auf Grund privatsicherungsfinaler Vorleistung gew$\ddot{a}$rleistet wird. Der kompensatorische Bereich beschr$\ddot{a}$nkt sich auf die schwere infantile Zerebralparese (Cerebralparese) beim medizinischen Geburtsbehandlung. Schlie${\ss}$lich w$\ddot{u}$rde diese Arbeit erw$\ddot{u}$nscht sein, zur Konkretisierung des Voraussetzungen f$\ddot{u}$r die Kompensation nach ${\S}$ 46 Abs. 1 u. 4 des obigen Gesetzes beitragen zu k$\ddot{o}$nnen, welcher spatestens am 8. 4. 2013. zur Geltung gebracht sein sollte.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.220-226
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• 2000

The piezoelectric material for piezoelectric transformer needs the high electromechanical coupling factor( $k_{p}$) the piezoelectric constant( $d_{33}$) and the mechanical quality factor( $Q_{m}$)in order to obtain high voltage step-up ratio and low temperature rising. In this study the piezoelectric transformers were fabricated using Pb［$Zr_{0.45}$/ $Ti_{0}$48//L $u_{0.02}$(M $n_{1}$3//S $b_{2}$3/)$_{0.05}$］ $O_3$(PMS-PZT) and Pb［Z $r_{0.25}$/ $Ti_{0.375}$(M $g_{1}$3//N $b_{2}$3/)$_{0.375}$］ $O_3$+0.5wt%Mn $O_2$(PMN-PZT) ceramics. The piezoelectric properties of PMS-PZT and PMN-PZT were measured. The voltage set-up ratios of the piezoelectric transformers using PMS-PZT and PMN-PZT were the value of 15, 20 respectively under 100$_{KΩ}$ in Rosen type transformer.r.ormer.r.r.r.r.r.r.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.537-542
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• 2004

$V_{2}O_{5}/TiO_{2}$ catalysts promoted with Mn were prepared and tested for selective catalytic reduction of NOx in $NH_3.$ The effects of promoter content, degree of catalyst loading were investigated for NOx activity while changing temperatures, mole ratio, space velocity and $O_2$ concentration. Among the various $V-{2}O_{5}$ catalysts having different metal loadings, $V-{2}O_{5}$(1 wt.%) catalyst showed the highest activity(98%) under wide temperature range of $200-250^{\circ}C.$ When the $V-{2}O_{5}$ catalyst was further modified with 5 wt.% Mn as a promoter, the highest activity(90-47%) was obtained over the low temperature windows of $100-200^{\circ}C.$ From Mn-$V_{2}O_{5}/TiO_{2}$, it was found that by addition of 5 wt.% Mn on $V_{2}O_{5}/TiO_{2}$ catalyst, reduction activity of catalyst was improved, which resulted in the increase of catalytic activity and NOx reduction. According to the results, NOx removal decreased for 10%, but the reaction temperature down to $100^{\circ}C.$