• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.68-72
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• 1997

In this paper, to obtain the YbB $a_2$C $u_3$ $O_{x}$ superconductor, the mixed Powders of Y $b_2$ $O_3$, BaC $O_3$, CuO and Y $b_2$BaCu $O_{5}$, BaCu $O_2$ were used and the various calcining conditions were applied for the 123 phase of YbB $a_2$C $u_3$ $O_{x}$. Samples were prepared by the mixed oxide method and calcined with various temperatures of 88$0^{\circ}C$ ~91$0^{\circ}C$ . It was observed that the distribution of YbB $a_2$C $u_3$ $O_{x}$ phase which was calcined at 90$0^{\circ}C$ for 12 hours and 99 hours. But the result of long time calcination(99 hrs), the 123 phase of YbB $a_2$C $u_3$ $O_{x}$ was existed between 89$0^{\circ}C$ and 91$0^{\circ}C$ . And the best case could be obtained at the calcination temp. of 90$0^{\circ}C$ from the mixed Powder of YbB $a_2$C $u_3$ $O_{5}$ and Bacu $O_2$ which were prepared individually.idually.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.612-617
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• 2013

The versatile, hitherto unreported 3-(4-(2-phenyldiazenyl)-2-oxo-2H-chromen-3-yl)-3-oxopropanenitrile 3 was prepared by two convenient routes: either by the reaction of ethyl 4-(2-phenyldiazenyl)-2-oxo-2H-chromen-3-carboxylate 2 with acetonitrile in the presence of sodium hydride or by treatment of 4-(2-phenyldiazenyl)-3-(2-bromoacetyl)-2H-chromen-2- one 5 with potassium cyanide. Reaction of 3 with heterocyclic diazonium salts 6, 7, 14 and 17 furnished the corresponding hydrazones 8, 9, 15 and 18. The latter hydrazones underwent intramolecular cyclization into the corresponding pyrazolo[5,1- c]-1,2,4-triazine 10, 1,2,4-triazolo[5,1-c]-1,2,4-triazine 11, 1,2,4-triazino[4,3-b]indazole 16 and imidazo[2,1-c]-1,2,4-triazine 19 derivatives, respectively upon refluxing in pyridine.

• Journal of Nutrition and Health
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• v.38 no.5
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• pp.352-363
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• 2005

The previous extensive in vitro studies on the antioxidative activities of a number of Korean grains, vegetables, seaweeds and mushrooms, and the various combinations of these food source exhibited a wide range of antioxidative activities, and four food mixtures composed of 5 kinds of foods (5A, 5B, 5C and 5D) were designed from 16 selective foods showing. high antioxidant effect, in vitro, to find the good combinations for the meal planning. Mixture 5B or 5C contained very high levels of total flavonoid and polyphenol, and ethanol extract from 5A, 5B or 5C showed very strong inhibitory effects against in vitro $Fe^{2+}-induced$ lipid peroxidation and ethanol extract from 5B or 5C showed remarkable DPPH radical scavenging effect and lipid peroxide-protein conjugation inhibition effect. And in vivo study was also carried out with two mixtures (5B, 5C). Powders (P5B, P5C) or ethanol extracts (E5B, E5C) of these mixtures were supplemented to Sprague-Dawley rats fed on high fat $(15\%)-high$ cholesterol $(1\%)$ semipurified diet for 5 weeks. The total antioxidant power in serum was significantly higher in P5B, P5C, E5B and E5C groups than in high fat control group, and $ascorbate-Fe^{2+}-induced$ TBARS was significantly lowered by E5B supplementation in rat liver. In liver tissue, Cu, Zn-SOD activity was significantly higher in P5B and E5B groups than in high fat control group, while catalase or GSH-peroxidase (GPx) activity was not changed by any supplementations. In kidney, Cu, Zn­SOD activity was significantly higher in P5B group than in high fat control group, while GPx activity was not changed by any supplementations. Taken together, mixture 5B and 5C showed very strong antioxidative effects both in vitro and in vivo. Therefore, the ingredient Korean foods of 5B and 5C could be recommended to take a lot together for prevention from age-related chronic diseases.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2325-2329
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• 2013

Second-order rate constants $k_N$ have been measured for reactions of benzyl 2-pyridyl thionocarbonate (4b) and t-butyl 2-pyridyl thionocarbonate (5b) with a series of cyclic secondary amines in MeCN at $25.0{\pm}0.1^{\circ}C$. The $k_N$ values for the reactions of 4b and 5b have been compared with those reported previously for the corresponding reactions of benzyl 2-pyridyl carbonate (4a) and t-butyl 2-pyridyl carbonate (5a) to investigate the effect of changing the electrophilic center from C=O to C=S on reactivity and reaction mechanism. The thiono compound 4b is more reactive than its oxygen analogue 4a. The Br${\o}$nsted-type plots for the reactions of 4a and 4b are linear with ${\beta}_{nuc}=0.57$ and 0.37, respectively. The reactions of 4a were previously reported to proceed through a concerted mechanism, while those of 4b in this study have been concluded to proceed through a stepwise mechanism with formation of an intermediate being the rate-determining step on the basis of the ${\beta}_{nuc}$ value of 0.37. Enhanced polarizability upon changing the C=O in 4a by C=S has been suggested to be responsible for the reactivity order and the contrasting reaction mechanisms. In contrast, the reactivity of 5a and 5b is similar, but they are much less reactive than 4a and 4b. Furthermore, the reactions of 5a and 5b have been concluded to proceed through the same mechanism (i.e., a concerted mechanism) on the basis of linear Bronsted-type plots with ${\beta}_{nuc}=0.45$ or 0.47. It has been concluded that the strong steric hindrance exerted by the t-Bu in 5a and 5b causes a decrease in their reactivity and forces the reactions to proceed through a concerted mechanism.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.323-328
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• 1993

Benzo(a)pyrene [B(a)P], one of the polycyclic aromatic hydrocarbons (PAHs) is known as a potent carcinogen. As lipid consumption increases recently, the toxic effect of overheated lipid foods and fats ＆ oils were reported increasingly. In this study, the contents of B(a)p, other PAHs and rancidities of soybean oil were determined, and then the proper heating temperature, time and frequency were recommended, The work was carried out using soybean oil heated at $180\pm$5^{\circ}C$$, $200\pm$5^{\circ}C$$, and $300\pm$5^{\circ}C$$,for 50 hours. Acid Value(AV) and Conjugated Diene Value of samples were determined. The contents of B(a)P and other PAHs contents of all samples were masured by HPLC/UV method. The results obtained were as follows; Each content of PAHs in the fresh soybean oil was: Pyr 1.093, B(a)A 0.986, Ch 1.147, DMBA 1.082, B(e)P 0.664, Per 1.135, B(a)P 0.146, DBA 1.053, 3-MC 0.05 rg/kg. When the soybean oil was heated at $180\pm$5^{\circ}C$$, for 10, 20, 30, and 50 hours, B(a)P conterlts in heated soybean oils were 0.391, 0.692, 0.451, and 0.372 $\mu\textrm{g}$/kg respectively. Acid value of them were 0.26, 0.26, 0.29, and 0.33, and conjugated diene value was 0.67, 0.76, 0.99, and 1.04, respectively. When the soybean oil was heated at $200\pm$5^{\circ}C$$,and $300\pm$5^{\circ}C$$,for 10, 20, 30, and 50 hours, B(a)P coiltents in soybean oil heated at $200\pm$5^{\circ}C$$,were 0.844, 0.512, 0.479 and 0.247 Ig/kg respectively, Acid value 0.22, 0.21, 0.23 and 0.51 and CDNV 0.39, 0.49, 3.27, and 3.89. B(a)P contents in soybean oil heated at $300\pm$5^{\circ}C$$,were 0.466, 0.706, 0.607 and 0.247$\mu\textrm{g}$/kg respectively, Acid value 0.47, 1.57, 3.90, and 6.42 and CDNV 0.65, 2.15, 3.00, and 3.88.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.228-231
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• 1991

The phenotyping of the sixth complement component (C6) was performed on plasma or serum samples from 383 unrelated Korean, by IEF and immunoblotting using anti-human C6 serum. Three common allotypes, C6 A, C6 B and C6 B2 and two rare allotypes, C6 Ml and C6 Mu were observed. The allele frequencies of C6*A, C6*B and C6*B2 were estimated to be 0.4399, 0.5144, 0.0392, respectively. These frequencies are similar to those of the Eastasian populations.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.279-285
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• 2003

Ferroelectric S $r_{0.9}$B $i_{2.1}$T $a_{1.8}$N $b_{0.2}$ thin films with 200 nm thicknesses were deposited on Pt/Ti $O_2$/ $SiO_2$/Si Substrates by a sol-gel method. In these experiments, Sr(O $C_2$ $H_{5}$)$_2$, Bi(TMHD)$_3$, Ta(O $C_2$ $H_{5}$)$_{5}$ and Nb(O $C_2$ $H_{5}$)$_{5}$ were used as precursors, which were dissolved in 2-methoxyethanol. After UV-irradiation and RTA processes, the remanent polarization value (2 $P_{r}$) of SBTN thin films with annealed at $650^{\circ}C$ was 8.49 and 11.94 $\mu$C/$\textrm{cm}^2$ at 3 V and 5 V, respectively.

• Korean Journal of Crystallography
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• v.6 no.1
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• pp.36-42
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• 1995

Two types of single crystals of the title compound [6-(2-pyridyl)-3, 5-hexadiyn-ol, PyHxD] were obtained by solution of n-hexane/CH2C12 and n-hexane/Et2O, and their molecular conformations are proved identical in spite of different of space groups; C22H18N2O2 (I), Mr=343.70, Monoclinic, Pa, a=14.595(2), b=5.413(2), c=12.218(2)Å, β=96.86(1)°, V=958.3Å3, Z=2, Dx=1.19 Mgm-3, λ(MoKα)=0.71069Å, μ=0.072mm-1, F(000)=360.0, T=292K, R=0.104 for 756 unique observed reflections. An asymmetric unit contains a dimer connected by two N-H…O intermolecular hydrogen bonds. C11H9NO (II), Mr=171.85, Monoclinic, P21/a, a=14.611(2), b=5.423(6), c=12.191(2)Å, β=96.89(1)°, V=959.0Å3, Z=4, Dx=1.19 Mgm-3, λ(MoKα)=0.71069Å, μ=0.072mm-1, F(000)=360.0, T=293K, R=0.066 for 824 unique observed reflection. The structural asymmetric unit contains a molecule, but two N-H…O hydrogen bonds related by controsymmetry make the molecules form a dimer. In both structure, the dihedral angle between the planar pyridyl ring and the plane defined by C(10)-C(11)-O connected by linear diyne chain is approximately normal, and the molecules are stacked along b-axis with the unit repeat of b-axis.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1420-1421
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• 2006

In this study, structural and micowave dielectric properties of the $Mg_{5}B_{4}O_{15}$ (B=Ta, Nb) cation-deficient perovskite ceeramics. The specimens are prepared through the solid-state route. According to the XRD pattern, $Mg_{4}Ta_{2}O_9$ and $MgTa_{2}O_6$ phase exist in calcined and sintered $Mg_{5}Ta_{4}O_{15}$ powder. Also $Mg_{5}Ta_{4}O_{15}$ phase added with increasing sintering temperature. In the case of calcined and sintered $Mg_{5}Nb_{4}O_{15}$ powder, single phase of $Mg_{5}Nb_{4}O_{15}$ were appeared. The bulk density and quality factor of the $Mg_{5}B_{4}O_{15}$ (B=Ta, Nb) ceramics were increased with sinteming temperature in $1400^{\circ}C{\sim}1450^{\circ}C$, but these were decreased in another sintering temperature. Dielectric constant of the $Mg_{5}Ta_{4}O_{15}$ ceramics was increased continuously with increasing of sintering temperature. And the dielectric constant of the $Mg_{5}Nb_{4}O_{15}$ ceramics was increased in $1400^{\circ}C{\sim}1450^{\circ}C$ but decreased in $1475^{\circ}C$. In the case of the $Mg_{5}Ta_{4}O_{15}$ and $Mg_{5}Nb_{4}O_{15}$ ceramics sintered at $1450^{\circ}C$ for 5h, the dielectric constant, quality factor, and temperature coefficient of the resonant frequency (TCRF) were 8.2, 259,473 GHz, -10.91 $ppm/^{\circ}C$ and 14, 37,350 GHz, -52.3 $ppm/^{\circ}C$, respectively.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.4
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• pp.55-59
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• 1999

One of lead free glass, Bi based solder glass is investigated for electronic packaging application. The melting temperature of glass about $550^{\circ}C$ at Bi based glass (70wt% $B_2O_3$ + l5wt%$B_2O_3$ + 8wt% $SiO_2$ + 2wt% $P_2O_5$ + 4wt% $A1_2O_3$ +lwt% ZnO) and varied with $P_2O_5$ content in this system. Crystallized glasses were obtainded after 1hr heat teratment at $450^{\circ}C$ with 10wt% of $P_2O_5$ addition. Much higher melting temperature was observed at $B_2O_3$ rich composition area.