• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.921-928
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• 2007

Three different phosphonated trisbipyridine ruthenium complexes, [(4-CH3-4'-CH2PO(OH)2-2,2'-bipyridine)- (bpy)2Ru]·(PF6)2 (Ru-P1), [(4-CH3-4'-CH2PO(OH)2-2,2'-bipyridine)3Ru]·(PF6)2 (Ru-P2), and [(4,4'-CH2PO- (OH)2-2,2'-bipyridine)3Ru]·(PF6)2 (Ru-P3) were synthesized and their photochemical and electrochemical properties were studied. These ruthenium complexes were strongly adsorbed on the surface of the layered metal oxide semiconductor K4Nb6O17 that was partially acid-exchanged and sensitized up to pH 10, while the carboxylated ruthenium complex, (4,4'-COOH-2,2'-bipyridine)3Ru·Cl2 (Ru-C) that was previously studied was sensitized only below pH 4. The visible light water reduction at K4Nb6O17 that was internally platinized and sensitized by these phosphonated Ru-complexes was comparatively studied using a reversible electron donor iodide.

• Communications of the Korean Mathematical Society
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• v.9 no.4
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• pp.933-944
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• 1994

Let $\pi : P \to S^4$ be a principal G-bundle over $S^4$ whose the structure group G is a compact, connected, simple Lie group. Since $\pi_3(G) = \pi_4 (BG) = Z$, we can classify the principal bundle $P_k$ over $S^4$ by the map $S^4 \to BG$ of degree k. Atiyah and Jones [2] showed that $C_k = A_k/g^b_k$ is homotopy equivalent to $\Omega^3_k G \simeq \Omega^4_k BG$ where $A_k$ is the space of the all connections in $P_k$ and $g^b_k$ is the based gauge group which consists of all base point preserving automorphisms on $P_k$. Here $\Omega^nX$ is the space of all base-point preserving continuous map from $S^n$ to X. Let $M_k$ be the space of based gauge equivalence classes of all connections in $P_k$ satisfying the Yang-Mills self-duality equations, which we call the moduli space of G instantons.

• Natural Product Sciences
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• v.18 no.2
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• pp.97-101
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• 2012

Six lignan compounds, 1-(17,21-dihydroxyphenyl)-9-(12,13-dihydroxyphenyl)-1-nonanone (malabaricone C) (1), 7'-(3',4'-methylenedioxyphenyl)-8,8'-dimethyl-7-(3,4-dihydroxyphenyl)-butane (2), 7'-(3',4'-dimethoxyphenyl)-8,8'-dimethyl-7-(3-methoxy-4-hydroxyphenyl)-butane (3), 7-(4-hydroxy-3-methoxyphenyl)-7'-(3',4'-methylenedioxyphenyl)-8,8'-lignan-7-methyl ether (4), (+)-erythro-(7S,8R)-${\Delta}^{8^'}$-7-hydroxy-3,4,3',5'-tetramethoxy-8-O-4'-neolignan (5), and (+)-erythro-(7S,8R)-${\Delta}^{8^'}$-7-acetoxy-3,4,3',5'-tetramethoxy-8-O-4'-neolignan (6), were isolated from the seeds of Myristica fragrans. The chemical structures of these compounds were determined on the basis of spectroscopic analyses including 2D NMR. Compounds 1 - 6 were evaluated for their cytotoxic activity against the HL-60, MCF-7, and A549 cancer cell lines in in vitro.

• Journal of Food Hygiene and Safety
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• v.24 no.3
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• pp.211-216
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• 2009

In order to cope with risk issues of overseas on 4,4'-diaminodiphenylmethane (4,4'-MDA) known to used in the production of polyamide resins, we investigated on 4,4'-MDA migration from plastic cooking utensils. 93 samples of plastic cooking utensils were collected from the retail markets in 7 major cities of Korea during March to June, 2007 and 4,4'-MDA levels migrated to food simulants, water, 4% acetic acid, 20% ethanol and n-heptane, on plastic cooking utensils was quantified by liquid chromatography with tandem mass spectrometry (LC-MS/MS). 4,4'-MDA was detected in 14 samples, and the levels of 4,4'-MDA migrated to food simulants were in the range of $0.001{\sim}0.026$ ppm. Among them, the 4,4'-MDA migration amounts of 2 samples were above 0.01 ppm defined by the EU.

• Journal of the Korean Chemical Society
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• v.52 no.4
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• pp.439-444
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• 2008

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.478-500
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• 1994

The preparation of potassium hexatitanate whisker by flux method was investigated. In this study, 8 types synthesis of flux such as $V_2O_5$, $Bi_2O_3$, $B_2O_3$, $Pb_3O_4$, KCl, $K_4P_2O_7$, $K_2WO_4$ and $K_2MoO_4$ were tested to find a suitable flux for the synthesis of potassium hexatitanate whisker. Effects of various reaction variables such as reaction temperature, time, $TiO_2$ mole ratio to $K_2CO_3$, flux mole ratio to the mixture of $K_2CO_3$ and $TiO_2$, and slow-cooling treatment on the crystallization of potassium hexatitanate whisker were investigated. $K_2MoO_4$ and $K_2WO_4$ were better flux than others tested for the synthesis of potassium hexatitanate. In the presence of $K_2MoO_4$ or $K_2WO_4$ flux, the optimum condition for the synthesis of potassium hexatitanate whisker was that reaction temperature of $1000{\sim}1100^{\circ}C$, reaction time of 5 hours, $TiO_2$ mole ratio to $K_2CO_3$ of 6.0, and flux mole ratio to mixture ($K_2O+nTiO_2$) of 4.0. Slow-cooling treatment showed good effect on the growth of long fibrous potassium hexatitanate.

• Journal of the Korean Chemical Society
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• v.41 no.4
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• pp.175-179
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• 1997

Luminescence of $Eu^{3+}$ has been studied in $Sr_{2-2x}Eu_xK_xSnO_4$ with two-dimensional $K_2NiF_4$ structure. The $^5D_o$ → $^7F_o$$Eu^{3+}$ ion represents the J=0 → J=0 transition which is forbidden by a Judd-Ofelt selection rule for electric dipole transition in 4f shell of $Eu^{3+}$ ions. However, the emission line of $^5D_o$ → $^7F_o$$Eu^{3+}$ emission spectra of Sr2-2xEuxKxSnO4$Sr_{2-2x}Eu_xK_xSnO_4$structure around $Eu^{3+}$ ions.

• Journal of Industrial Convergence
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• v.19 no.4
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• pp.23-28
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• 2021

This paper finds the regular pattern of n = [3, ∞] for Euler square game related with n = 6(6×6=36) thirty-six officer problem that is still unsolved problem. The solution of this problem is exists for n = [3, 10] without n = 6. Also, previous researchers finds the random assigned solution for specific number using computer programming. Therefore, the solution of n = [11, ∞] Euler squares are unsolved problem because of anything but easy. This paper attempts to find generalized patterns for domains that have been extended to n = [3, ∞], while existing studies have been limited to n = [3, 10]. This paper classify the n = [3, ∞] into n = odd, 4k even, 4k+2 even of three classes. Then we find the simple regular pattern solution for n = odd and 4k even(n/2 = even). But we can't find the regular pattern for 4k+2 even(n/2 = odd).

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.218-219
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• 2015

본 논문에서는 스마트폰으로 촬영한 비디오 영상이나 일반 캠코더로 촬영한 비디오 영상을 4K 고화질 콘텐츠로 제작하는 것을 제안한다. 대화면 디스플레이와 고해상도 디스플레이가 점차 확대되면서 고화질 콘텐츠의 필요가 증대됨으로 이에 일반적으로 촬영된 영상을 비디오 편집기법을 이용하여 4K 고화질 해상도의 영상 제작을 제안하다. 하지만 일반 비디오카메라로 촬영한 영상을 4K 콘텐츠로 완전히 적용하기 위해서는 촬영에서 4K 카메라로 촬영하고 편집하면 4K 콘텐츠로 보다 해상도가 높은 콘텐츠를 제작할 수 있다고 사료한다.

• Journal of Integrative Natural Science
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• v.10 no.3
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• pp.131-136
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• 2017

The chemical shifts in the $^{13}C$ NMR spectra of 2,3,4,5-tetraphenyl-1-silacyclopentdienide dianion $[SiC_4Ph_4]^{2-}{\cdot}2[K^+]$ (3) and 2,3,4,5-tetraphenyl-1-germacyclopentdienide dianion $[GeC_4Ph_4]^{2-}{\cdot}2[K^+]$ (4) were compared to those of $[SiC_4Ph_4]^{2-}{\cdot}2[Li^+]$ (5), $[SiC_4Ph_4]^{2-}{\cdot}2[Na^+]$ (6), and $[GeC_4Ph_4]^{2-}{\cdot}2[Li^+]$ (7). The average polarizations in two phenyl groups of two potassium salts are decreased over 15% to 20% comparing to those of the lithium salts and sodium salt {$[EC_4Ph_4]^{2-}{\cdot}2[M^+]$ (E=Si, Ge, M=Li, Na) due to the effect of the counter potassium cation.