• Phonetics and Speech Sciences
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• v.10 no.2
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• pp.15-24
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• 2018

Earlier studies reported that the /o/ and /u/ phonemes of Seoul Korean were currently merging in the F1/F2 space. However, studies on perception tests have shown that rates of correctness were high, even in cases where the two vowels overlapped. This study explores whether there is another acoustic parameter that differentiates /o/ from /u/, besides the F1/F2 contrast. Seventy-five native speakers of Seoul Korean, born between 1953 and 1999, participated in a production test. The data collected were analyzed in terms of F1 and F2, H1-H2, and F0. The result shows that the /o/ and /u/ of female speakers almost overlap in the F1/F2 space for all ages, while H1-H2 values are significantly different between the two vowels regardless of age. On the other hand, the /o/ and /u/ of male speakers are largely well separated in the F1/F2 space, while the H1-H2 values between the two vowels are very close at all ages. F0 effect is relatively small for both male and female speakers, even though there is a statistically significant difference. The result of this study provides evidence that female speakers use phonation differences to distinguish /o/ from /u/, and that the F1/F2 contrast has been replaced by H1-H2 values.

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.447-454
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• 2003

Samples were prepared by the solid-state reaction method. The nominal composition of the samples was B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+{delta}$ prepared from powder of B $i_2$ $O_3$, PbO, SrC $O_3$, CaC $O_3$, and CuO. They were pulverized, mixed with AgO, A $u_2$ $O_3$and MgO of 50 wt%. Finally, they were sintered at 820 to 85$0^{\circ}C$ in air. The structural characteristics, the microstructure of surface and the critical temperature with respect to the each samples were analyzed by XRD, $T_{c}$, SEM and EDS respectively. It was found that the the critical temperature of the silver oxide additive samples (99.58 K) is higher than those of gold or magnesium oxides additive samples, but all those values are lower than that of pure Bi-2223 phase. The microstructure of surface showed the tendency which the AgO additive samples become more minuteness than A $u_2$ $O_3$ and MgO additive samples.s.samples.s.

• Nuclear Engineering and Technology
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• v.31 no.3
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• pp.335-343
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• 1999

The effects of N $b_2$ $O_{5}$ and oxygen potential on the densification and grain growth of U $O_2$ fuel have been investigated.0.3 wt% N $b_2$ $O_{5}$ -doped U $O_2$fuel pellets were sintered at 1$700^{\circ}C$ for 4 hours in sintering atmospheres which have various ratios of $H_2O$ to $H_2$ gas. Compared with those of undoped U $O_2$ pellets, the sintered density and grain size of the 0.3 wt% N $b_2$ $O_{5}$ -doped U $O_2$ pellet increase under the $H_2O$/ $H_2$ gas ratio of 5.0$\times$10$^{-3}$ to 1.0$\times$10$^{-2}$ and under the $H_2O$/ $H_2$gas ratio of 5.0$\times$10$^{-3}$ to $1.5\times$10$^{-2}$ , respectively. The sintering of U $O_2$fuel pellets containing 0.1 wt% to 0.5 wt% N $b_2$ $O_{5}$ was carried out at 168$0^{\circ}C$ for 4 hours. The enhancing effect of N $b_2$ $O_{5}$ on the sintered density and grain size becomes larger as the N $b_2$ $O_{5}$ content increases. The solubility limit of N $b_2$ $O_{5}$ in U $O_{2}$ seems to be between 0.3 wt% and 0.5 wt%, and beyond the solubility limit the second phase whose composition corresponds near to N $b_2$U $O_{6}$ is precipitated on grain boundary. The enhancement of densification and grain growth in U $O_2$ is attributed to the increased concentration of a uranium vacancy which is formed by the interstitial N $b^{4+}$ ion in the U $O_2$ lattice.

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.6
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• pp.305-322
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• 2002

Seit dem Ereignis des Tunnbaus zu Babel. versucht man, Sprachbarriere zu $\"{u}berwinden$. Eine dieser $Bem\"{u}hungen$ hat seit der 60er Jahre zur Anwendung von Computern in der $\"{U}bersetzung gef\"{u}hrt$. Bei der automatischen $\"{U}bersetzung\;\"{u}bernimmt$ der Computer die Aufgabe, Texte von einer $nat\"{u}rlichen$ Sprache in eine andere zu $\"{u}bertragen$. Die vorliegende Arbeit $besch\"{a}ftigt$ sich mit verschiedenen Arten von den sogenannten $\"{U}bersetzungspatterns\;f\"{u}r$ die automatische $\"{U}bersetzung$ Koreanisch­Deutsch. Zu den $\"{U}bersetzungspatterns\;geh\"{o}ren$ u.a. Verbphrasen-Pattern, Nominalphrasen-Pattern und Verbindungspattern. Unter 'Verbphrasen-Pattern' versteht man einen gekoppelten Subkategorisierungsrahmen der Verben zweier Sprachen. 'NominaIphrasen-Pattern' verstehen sich als $\"{U}bersetzungspattern$ der Nominalphrasen. Unter 'Verbindungs-Pattern' werden $\"{U}bersetzungspattern$ von komplexen $S\"{a}tze$ verstanden, wie z.B. Satzkoordinationen und $S\"{a}tze$ mit eingebetten $S\"{a}tzen$. Als Vorteil des Ansatzes $z\"{a}hlen$ u.a. die Wiederverwendbarkeit bzw. das leichte Management der Patterns, die $Beschreibungsm\"{o}glichkeit$ in der lexikalischen Ebene, die Generieung der naturlichen $Ziels\"{a}tze$ und die leichte Verbesserung der $\"{U}bersetzungsqualit\"{a}t$. Die in dieser Arbeit vorgestellten $\"{U}bersetzungspatterns\;k\"{o}nnen$ aIs Hilfsmittel $f\"{u}r$ Deutschunterrichte, Aufsatzhilfesysteme und elektronische Koreanisch-Deutsch $W\"{o}rterb\"{u}cher$ eingesetzt werden.

• Journal of the Korean Mathematical Society
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• v.47 no.3
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• pp.547-572
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• 2010

We study existence of positive solutions of the classical nonlinear Schr$\ddot{o}$dinger equation $-{\Delta}u\;+\;V(x)u\;-\;f(x,\;u)\;-\;H(x)u^{2*-1}\;=\;0$, u > 0 in $\mathbb{R}^n$ $u\;{\rightarrow}\;0\;as\;|x|\;{\rightarrow}\;{\infty}$. In fact, we consider the following more general quasi-linear Schr$\ddot{o}$odinger equation $-div(|{\nabla}u|^{m-2}{\nabla}u)\;+\;V(x)u^{m-1}$ $-f(x,\;u)\;-\;H(x)u^{m^*-1}\;=\;0$, u > 0 in $\mathbb{R}^n$ $u\;{\rightarrow}\;0\;as\;|x|\;{\rightarrow}\;{\infty}$, where m $\in$ (1, n) is a positive number and $m^*\;:=\;\frac{mn}{n-m}\;>\;0$, is the corresponding critical Sobolev embedding number in $\mathbb{R}^n$. Under appropriate conditions on the functions V(x), f(x, u) and H(x), existence and non-existence results of positive solutions have been established.

• Economic and Environmental Geology
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• v.36 no.3
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• pp.225-232
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• 2003

Three piston cores. obtained from the northwestern Ulleung Basin of the East Sea, are analyzed to study the tephrostratigraphy of the late Quaternary core sediments and to reveal the comparative characteristics of the tephra layers. The cores consist mainly of the muddy sediments that are partly interbedded with lapilli tephra and ash layers. The muds are further divided into hemipelagic and turbiditic mud facies. The hemipelagic facies is dominated by bioturbated mud and crudely laminated mud, whereas the turbiditic facies includes mainly thinly laminated mud and homogeneous mud, and often alternates with non-turbiditic muds. According to microscopic observation and EDX analysis, three tephra layers of the Ulleung-Oki (U-Oki; ca. 9.3 ka), Aira-Tanzawa (AT: ca. 22~24.7 ka) and Ulleung-Yamato (U-Ym; ca. 25~33 ka) are identified in the study cores. Among these, the U-Oki and U-Ym layers, originating from the Ulleung Island, consist mainly of massive-type glass shards with alkali feldspar. Both of the tephra layers contain a lower content of SiO$_2$ (57~66.5 wt.%) and a higher content of Na$_2$O+K$_2$O (11~16 wt.%) than the AT layer (SiO$_2$=75~78.5 wt.%, Na$_2$O+K$_2$O=6.5~9 wt.%) that consists of typical plane-type and/or bubble-wall glass grains. Compared with that of the U-Ym layer, a sedimentary facies of the U-Oki layer is very thick and contains three stratigraphic units, probably due to relatively large and different supplies of pyroclastic sediments. Thus, the eruption of Ulleung Volcano (ca. 7,300 B.C.) is thought to have had a more powerful effect on depositional environment than the U-Ym eruption.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.435-435
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• 2011

The electronic structure and various physical properties of CeO2, Ce2O3, PrO2, and Pr2O3 have been studied from the framework of Ab-initio by the all-electron projector-augmented-wave (PAW) method, as implemented VASP (Vienna Ab-initio Simulation Package). The generalized gradient approximation (GGA) with effective U (Ueff) has been used to explain the strong on-site Coulomb repulsion among the localized Ce 4f electrons. The dependence of selected observables of these materials on the Ueff parameter has been scrutinized. The studied properties contain lattice constants, density of states, and reaction energies of CeO2, Ce2O3, PrO2, and Pr2O3. For CeO2 and PrO2, the GGA(PBE)+U results are in good agreement with experimental data whereas for the computational calculationally more demanding Ce2O3 and Pr2O3 both approaches give comparable accuracy. This results represent that by choosing an appropriate Ueff it is possible to reliably describe structural and electronic properties of CeO2, Ce2O3, PrO2, and Pr2O3, which enables modeling of oxygen reduction reaction processes involving ceria-based materials.

• Nuclear Engineering and Technology
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• v.15 no.3
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• pp.197-206
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• 1983

The slightly hyperstoichiometric uranium dioxide, i.e. U $O_{2.005}$ and U $O_{2.01}$ within a range of the requirement for the use of a nuclear fuel, were sintered directly in an atmosphere of $CO_2$/CO mixture without any succeeding reduction process. The kinetics of sintering in the late stage were investigated for various O/U ratios. A sintering diagram, which show the relation of Temperature-Time-Density-Grain size, was established for each O/U ratio. Only by controlling the oxygen partial pressure in the sintering atmosphere, U $O_2$ pellet could be sintered very easily at low temperature 1050$^{\circ}$～120$0^{\circ}C$ with a density above 95% T.D. and average grain size above 7${\mu}{\textrm}{m}$. It was found that the rate of grain growth follows D=(Kt)$^{1}$4/ in the late stage of sintering. And the activation energies for grain growth in the final sintering stage were found to be 75, 64 and 62kca1/mo1 for U $O_{2.005}$, U $O_{2.01}$ and U $O_{2.10}$, respectively. Although no significant differences are obtained between the activation energies for different O/U ratios, the sinterability is enhanced considerably with increasing the oxygen partial pressure in the sintering atmosphere.tmosphere.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.967-972
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• 2001

The crystal and defect structures of U $O_{x}$(x=2.0, 2.03, 2.14, 2.19, 2.20 and 2.26) were analysed by rietveld refinement and the results were compared to the U-O phase diagram. Neutron diffraction data were collected in the temperature range of RT~100$0^{\circ}C$. The specimens of x=2.14, 2.19, and 2.20 consisted of two phase: $UO_{2+x}$(Fm3m, a≒5.4$\AA$) and $U_4$$O_{9}$(I43d, a≒21.8$\AA$). The proportion of the $UO_{2+x}$(Fm3m) phase increased with increasing the temperature. The variation of the proportion of the two phases with temperature in the U $O_{2.2}$ and U $O_{2.18}$ samples showed some deviation from the expected values from the phase diagram especially at the high temperature range. The phase transitions ${\gamma}$longrightarrow$\beta$longrightarrow$\alpha$ of $U_4$$O_{9}$ were discussed in relation with the phase separation.eparation.ion.

• Phonetics and Speech Sciences
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• v.5 no.2
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• pp.33-41
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• 2013

This is a follow-up study on Han and Kang (2013) which argued that the Euclidean distances between /o/ and /u/ in Seoul Korean decreased in the first syllable position as speakers were among younger female speakers but not for male speakers, whereas in the second syllable position both gender groups showed a cross-generational decreasing effect of the Euclidean distance between /o/ and /u/. This study normalized the same data in Han and Kang (2013) which measured 12 speakers (six males and six females) for each Age group and investigated the spectral changes vowels /o/ and /u/ between age and gender, using the log-mean normalized statistical results. This study also examined overlap fraction values generated in SOAM 2D ($F1{\times}F2$) (cf. Wassink, 2006), which may also indicate the proximity of two vowels in question. The results showed that /o/ and /u/ vowels were making closer with /o/ raising for female speakers in $V_1$ and $V_2$ positions but only in the $V_2$ position for male speakers. That is, females led the upward movement of peripheral /o/ vowel, just like the raising of 'e' and 'o' in New York City (Labov, 1991). The results also showed that younger speakers used a rather narrow vowel space for the vowels. This also contributed to the proximity of the vowels /o/ and /u/, resulting in rather large overlap fraction values for younger speakers between these two vowels.