• Journal of Marine Bioscience and Biotechnology
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• v.11 no.1
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• pp.14-22
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• 2019

Omega-3 fatty acids and carotenoids, which are known as representative high-value substances derived from microalgae, are being studied from various diatoms. Most of the diatoms contain fucoxanthin and omega-3 fatty acid. Fucoxanthin produced by diatom has been reported as bioactive compounds exhibiting strong antioxidant, anticancer and anti-inflammatory activities. However, the low growth rate and fucoxanthin content of diatoms are one of the big obstacles to the industrial application. In this study, indigenous marine diatom Achnanthidium sp. BS-001 was isolated for a candidate of fucoxanthin producer. Light intensity and temperature for the culture of Achnanthidium sp. BS-001 were optimized on PhotoBiobox. Optimization of silicate concentration for increasing BS-001 biomass productivity was confirmed in F/2 medium with various concentration of sodium silicate. As a result, condition of light intensity, temperature, and silicate concentration for optimal cultivation were $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $18^{\circ}C$ and 0.106 mM, respectively. Maximum biomass productivity reaches to $154.3mg{\cdot}L^{-1}{\cdot}day^{-1}$, and then the content of omega-3 fatty acids and fucoxanthin were $19.4mg{\cdot}g^{-1}$, $9.05mg{\cdot}g^{-1}$, respectively. These results indicate that Achnanthidium sp. BS-001 has the potential to be used as a source of omega-3 fatty acids and fucoxanthin.

• Journal of the Korean Ceramic Society
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• v.31 no.11
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• pp.1378-1386
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• 1994

The characteristic of calcined BaTiO3 powder and sintered PTC ceramics was investigated varing with calcination temperature and time of BaTiO(C2O4)2.4H2O synthesized from BaCl2.2H2O, TiCl4, oxalic acid and ethanol by oxalic acid method. When the particle size was less than 0.1 ${\mu}{\textrm}{m}$ by controlling calcination temperature and time, the resistance at room temperature was measured very high (above M{{{{ OMEGA }}). However, when the calcined particle sizes ranged from 0.2 to 0.3 ${\mu}{\textrm}{m}$, the resistance was 100 {{{{ OMEGA }} (After sintering, the grain size was 10~30 ${\mu}{\textrm}{m}$ homogeneously with the addition of dopant in sintering, the resistivity, resistance, $\alpha$ value and jumped to were 110{{{{ OMEGA }}.cm, 24$^{\circ}C$/% and 106{{{{ OMEGA }}, respectively.

• Journal of the Korean Applied Science and Technology
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• v.18 no.3
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• pp.197-213
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• 2001

Conjugate trienoic acids (CTA) occurred in triacylglycerols (TGs) of the seed oils of Trichosanthes kirilowii, Momordica charantia and Aleurites fordii, and they were easily converted to their methyl esters in a mixture of sodium methoxide-methanol without any structural destruction. The main fatty acids in triacylglycerol (TG) fraction of the seed oils of Trichosanthes kirilowii are $C_{18:2{\omega}6}$ (32.2 mol %), $C_{18:3{\;}9c.11t,13c}$ (38.0 mol %) and $C_{18:1{\omega}9}$ (11.8 mol %), followed with $C_{16:0}$ (4.8 mol %) and $C_{18:0}$ (3.1 mol %). The TG fraction was resolved into 20 TG molecular species according to the partition number (PN) by reversed-phase (RP)-HPLC. The main TG species were $DT_{c2}$, $MDT_{c}$ and $D_{2}T_{c}$, of which amounts reached 63 mol % of total TG molecular species. The TG sample was fractionated into 11 fractions according to the number of double bond in the molecule by $Ag^{+}-HPLC$ and the species of $DT_{c2}$, $MDT_{c}$ and $D_{2}T_{c}$ were also eluted as main components. The TG species containing CTA showed unusual behaviours in the order of elution by HPLC ; first, TG moleular species of $DT_{c2}$ (D; dienoic acid, $T_{c}$; punicic acid, $T_{ci}$; ${\alpha}-eleostearic$ acid, M ; monoenoic acid, $S_{t}$; stearic acid) was eluted earlier than $Mt_{c2}$, although they have the same PN number of 40, and, secondly, the species of $DT_{ci2}$ with eight double bonds was eluted earlier than that of $D_2T_{ci}$ with seven double bonds. Intact TG of the seed oils of Momordica charantia contained mainly fatty acids such as $C_{18:3{\omega}9c,11t,13t}$ (57.7 mol %), $C_{18:1{\omega}9}$ (17.4 mol %), $C_{18:0}$ (12.3 mol %) and $C_{18:2{\omega}6}$ (10.6 mol %), and was classified into 13 fractions by RP-HPLC. The main TG species were as follows ; $MT_{ci2}$ [$(C_{18:1{\omega}9})(C_{18:3\;9c,11t,13t})_{2}$, 39.1 mol %] and $S_{t}T_{ci2}$ [$(C_{18:0})(C_{18:3\;9c,11t,13t})_2$, 33.9 mol %] comprising about 73 mol % of total TG species, accompanied by $DT_{ci2}$ [$(C_{18:2{\omega}6})(C_{18:3\;9c,11t,13t})_{2}$, 7.3 mol %], $D_{2}T_{ci}$ [$ (C_{18:2{\omega}6})_{2}(C_{18:3\;9c,11t,13t})$, 3.6 mol %] and $MDT_{ci}$ [$(C_{18:1{\omega}9})(C_{18:2{\omega}6})(C_{18:3\;9c,11t,13t})$, 3.5 mol %]. Simple TG species of $T_{ci3}$ [$(C_{18:3\;9c,11t,13t})_3]$ was present in a small amount of 1.4 mol %, but other simple TG species were not detected. The TG was also resolved into 11 fractions according to the number of double bond by $Ag^{+}-HPLC$, and the species were mainly occupied by $MT_{ci2}$ [$(C_{18:1{\omega}9})(C_{18:3\;9c,11t,13t})_{2}$, 39.4 mol %] and $S_tT-{ci2}$ [$(C_{18:0})(C_{18:3\;9c,11t,13t})_{2}$, 35.4 mol %] $DT_{ci2}$ species with eight double bonds was also developed faster than $D_2T_{ci}$ one with seven double bonds as indicated in the analysis of TG of the seed oils of T. kirilowii, and $MT_{ci2}$ species with cis, trans, trans-configurated double bond was eluted earlier than $MT_{c2}$ species with cis, trans, cis-configurated double bond. The main components of fatty acid in total TG fraction isolated from the seed oils of of Aleurites fordii were in the following order ; $C_{18:3\;9c,11t,13t}$ (81.2 mol %)> $C_{18:2{\omega}6}$ (8.5 mol %)> $C_{18:1{\omega}9}$ (5.4 mol %)$. With resolution of the TG by RP-HPLC, eight fractions such as $T_{ci3}$, $Dt_{ci2}$, $D_{2}T_{ci}$, $MT_{ci2}$, $PT_{ci2}$ (P; palmitic acid), $PMT_{ci}$, $PDT_{ci}$ and $S_{t}T_{ci2}$ ($S_{t}$; stearic acid) were isolated, respectively. TG species of $T_{ci3}$ [$(C_{18:3\;9c,11t,13t})_{3}$, 54.2 mol %], $DT_{ci2}$ [$(C_{18:2{\omega}6})(C_{18:3\;9c,11t,13t})_{2}$, 15.0 mol %] and $MT_{ci2}$ [$(C_{18:1{\omega}9})(C_{18:3 9c,11t,13t})_{2}$, 14.8 mol %] were present as main species.

• Communications of the Korean Mathematical Society
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• v.15 no.3
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• pp.549-553
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• 2000

For a continuous map of the circle to itself, we give necessary and sufficient conditions for the $\omega$-limit set of each nonwandering point to be minimal.

• Journal of the Korean Mathematical Society
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• v.32 no.3
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• pp.461-470
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• 1995

In this paper a capacitance matrix method is developed for the Poisson equation on a rectangle $$ (1-1) Lu \equiv -(u_{xx} + u_{yy} = f, (x, y) \in \Omega \equiv (0, 1) \times (0, 1) $$ with the homogeneous Dirichlet boundary condition $$ (1-2) u = 0, (x, y) \in \partial\Omega $$ where $\partial\Omega$ is the boundary of the region $\Omega$.

• Bulletin of the Korean Mathematical Society
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• v.50 no.4
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• pp.1235-1242
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• 2013

We give area and height estimates for cmc-graphs over a bounded planar $C^{2,{\alpha}}$ domain ${\Omega}{\subset}\mathbb{R}^3$. For a constant H satisfying $H^2{\mid}{\Omega}{\mid}{\leq}9{\pi}/16$, we show that the height $h$ of H-graphs over ${\Omega}$ with vanishing boundary satisfies ${\mid}h{\mid}$ < $(\tilde{r}/2{\pi})H{\mid}{\Omega}{\mid}$, where $\tilde{r}$ is the middle zero of $(x-1)(H^2{\mid}{\Omega}{\mid}(x+2)^2-9{\pi}(x-1))$. We use this height estimate to prove the following existence result for cmc H-graphs: for a constant H satisfying $H^2{\mid}{\Omega}{\mid}$ < $(\sqrt{297}-13){\pi}/8$, there exists an H-graph with vanishing boundary.

• Bulletin of the Korean Mathematical Society
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• v.38 no.3
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• pp.487-493
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• 2001

$Let \Omega$ be a bounded convex domain in C^n$ with smooth boundary. Let M be a subvariety of $\Omega$ which intersects $\partial$$\Omega$ transversally. Suppose that $\Omega$ is totally convex at any point of $\partial$M in the complex tangential directions.For f $\epsilon$O(M)$\bigcap$/TEX>$C^{\infty}$($\overline{M}$/TEX>), there exists F $\epsilon$ o ($\Omega$))$\bigcap$/TEX>$C^{\infty}$($\overline{\Omega}$/TEX>) such that F(z) = f(z) for z $\epsilon$ M.

• Journal of applied mathematics & informatics
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• v.6 no.3
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• pp.783-798
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• 1999

Nondeterministic finite Rabin-Scott's automata without initial and final states (2 $\omega$-FA) are considered. In this paper they are used to define so called sets of obstruction used also in various alge-braic systems and to consider similar problems for the formal languages theory. Thus we define sets of obstructions of languages(or, rather, 2$\omega$-languages) of such automata. We obtain that each 2$\omega$-language defined by 2 $\omega$-FA has the set of obstruction being a regular language. And vice versa for each regular language L(containing no proper subword of its another word) there exists a 2$\omega$ -FA having L as the set of obstructions.

• Journal of applied mathematics & informatics
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• v.35 no.3_4
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• pp.413-421
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• 2017

In this paper, we study the generalizations of Euler numbers and polynomials by using the q-extension with p-adic integral on $\mathbb{Z}_p$. We call these: the generalized q-${\omega}$-Euler numbers $E^{({\alpha})}_{n,q,{{\omega}}(a)$ and polynomials $E^{({\alpha})}_{n,q,{\omega}}(x;a)$. We investigate some elementary properties and relations for $E^{({\alpha})}_{n,q,{{\omega}}(a)$ and $E^{({\alpha})}_{n,q,{\omega}}(x;a)$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.935-938
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• 2010

Indium-tin-oxide (ITO) films show a low electrical resistance and high transmittance in the visible range of an optical spectrum. The transparent electrodes have to get resistivity and sheet resistance less than $1{\times}10^{-3}{\Omega}/cm$ and $10^3{\Omega}/sq$ respectively and transmittance over 80% at wavelength of 380nm~780nm. This study establishes DC magnetron sputtering process condition on ITO thin film by measuring electrical and optical properties of the thin film. As results, we obtained $300\;{\mu}{\Omega}cm$ resistivity of ITO films with good transmittance (above 90 %) under 90:10 wt% composition rate of $In_2O_3:SnO_2$. Also, we understood that the ITO thin film by DC magnetron sputtering depends on the deposition condition, especially substrate temperature, and the composition rate of $In_2O_3:SnO_2$ that is one of the most critical parameters was successfully optimized for high qualified transparent electrodes.