• Journal of the Korean Ceramic Society
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• v.35 no.9
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• pp.933-938
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• 1998

The hydration for the system of fluorogypsum and 20wt% blast furnace slag was investigated at liquid/soild ratio of 0.45 for 1, 3, and 7 days by using 3 kinds of accelerators such as K2SO4 Al2(SO4)3 $.$16-18H2O and AlK(SO4)2$.$12H2O After curing the hardened specimen was characterized by the compressive strength the content of combined water XRD, DTA and SEM It was found that the activating effect was increased in the order of K2SO4

• Natural Product Sciences
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• v.9 no.2
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• pp.109-111
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• 2003

A bioassay-guided fractionation of the active chloroform extracts of the rhizomes of Zingiber cassumunar Roxb. led to the isolation of a potential cytotoxic principle, curcumin (1), along with two inactive compounds, (E)-4-(3',4'- dimethoxyphenyl)but-3-en-1-ol (2) and (E)-4- (3',4'-dimethoxyphenyl)but-3-en-1- yl acetate (3). Curcumin (1) showed a significant cytotoxicity against several human cancer cell lines $(Col2;\;2.30,\;A549;\;12.30,\;SNU638;\;IC_{50}\;18.80\;{\mu}g/ml)$.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.406-410
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• 2001

For 4-conductor bundle transmission line spacer damper are equipped so as to keep the spacing between sub conductors. For 4-conductor bundle the subspan spacing of a spacer damper is determined and applied in order that the bundle may get restored to a normal state when 4-conductor bundle is rolled by rigid body vibration due to wind. But 4 conductors of 345kV 4-conductor bundle transmission line were twisted by the angle of $315^{\circ}$ for the first time korea. In this paper, we will analyze the reason of the power line twisting of 4-conductor bundle which occurred for the first time in korea and offer the preventive countermeasures for this

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.445-451
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• 1998

A series of 5-hydroxy-4-quinolone (3) and 5-methoxy-4-quinolone (4) derivatives were synthesized as truncated acridone analogues and evaluated for antitumor, antiheroes and antituberculosis activities. Among them 5-hydroxy-8-methoxy-quinolone showed potent antitumor activity ($IC_{50}$=17.7 $\mu\textrm{M}$ for HL60) which was greater than that of acronycine. However, these compounds didn't show any significant antiheroes or antituberculosis activity.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.39-42
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• 2008

[ $AB_2X_4$ ](A, B=Transition Metal, X=O, S, Se) are cubic spinel normal ferrimagnets, in which M ions occupy the tetrahedral sites and Cr ions occupy the octahedral sites. Recently, they have been investigated for behaviour of B site ions and A-B interaction. Polycrystalline $[Co_{0.9}Zn_{0.1}]_A[Cr_{1.98}{^{57}Fe_{0.02}}]_BO_4$ compound was prepared by wet-chemical process. The ferrimagnetic transition was observed around 90K. $M\"{o}ssbauer$ absorption spectra at 4.2K show that the well-developed two sextets are superposed with small difference in hyperfine fields($H_{hf}$). The hyperfine fields of $CoCr_{1.98}{^{57}Fe_{0.02}}O_4$ and $Co_{0.9}Zn_{0.1}Cr_{1.98}{^{57}Fe_{0.02}}O_4$ were determined to be 488, 478 kOe and 486, 468 kOe, respectively. We notice that the one of the magnetic hyperfine field values changes with Zn ion substitution. These results suggest the incommensurate states and spin-reorientation temperature($T_S=18K$) changes with Zn ions substitution below spin-reorientation temperature($T_S=28K$) of $CoCr_{1.98}{^{57}Fe_{0.02}}O_4$

• Reproductive and Developmental Biology
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• v.32 no.1
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• pp.33-38
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• 2008

DNA methylation is involved in tissue-specific gene control and essential for normal embryo development Octamer-binding transcription factor 4 (Oct-4) is one of the most important transcription factors for early differentiation. This study was performed whether the bovine Oct-4 is tissue specific or developmental dependent epigenetic mark, we investigated transcripts and the methylation status of CpGs of 5'-promoter region of Oct-4 in bovine preimplantation embryos. Oct-4 transcripts were highly detected in morula and blastocyst, while they were present low levels in sperm and 2- to 8-cell stage embryos. These results suggest that de novo expression of Oct-4 initiates at morula stage of embryogenesis. Here we determined that there is a tissue-dependent differentially methylated region (T-DMR) in the 5'-promoter region of Oct-4. The methylation status of the Oct-4 T-DMR was distinctively different in the oocyte from that in the sperm and adult somatic tissues and changed from zygote to blastocyst stage, suggesting that active methylation and demethylation occur during preimplantation development. Based on these results, the 5'-promoter region of Oct-4 gene is target for DNA methylation and the methylation status changes variously during embryonic development in bovine.

• Macromolecular Research
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• v.8 no.1
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• pp.19-25
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• 2000

Aromatic diamine monomers containing allylic ester linkage, 1,5-bis(4-aminobenzoate)-1,2,3,4-tetrahydronaphthalene (4-DABTN) and 1,5-bis(3-amin obenzoate)-1,2,3,4-tetrahydronaphthalene (3-DABTN) were synthesized through the reaction of 1,5-dihydroxy-1,2,3,4-tetrahydronaphthalene and 4- or 3-nitrobenzoly chloride. By the reaction of these diamines with pyromellitic dianhydride (PMDA) or 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), poly(amic acid)s were obtained. The inherent viscosities of the poly(amic acid)s were between 0.55 and 1.31 dL/g. The poly(amic acid)s were converted to polyimides by chemical imidization. The thermogravimetric analysis (TGA) thermograms of these polyimides showed temperatures of 5% weight loss between 323 and 389$^{\circ}C$ in nitrogen atmosphere. The model compound ,1,5-bis (4-nitrobenzoate)-1,2,3,4-tetrahydronaphthalene (4-DNBTN), was decomposed to 4-nitrobenzoic acid and 5-(4-nitrobenzoate)-3,4-dihydronaphthalene upon addition of CF$_3$COOH.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.895-897
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• 1998

The optical spectra of microwave plasma by four kinds of gases($N_2$, $N_2-CH_4$, $H_{2}-CH_{4}$ and Air-$CH_4$) have been measured for investigating 388.4[nm] peak which has the same intensity as $H_{\alpha}$(656.4[nm]) peak. A 388.4[nm] peak by $N_2$ plasma, $N_{2}-CH_{4}$ plasma and Air-$CH_4$ plasma may be CN peak because it is with 337.1, 357.8 and 316.0[nm] peaks by $N_2$. And a 388.4[nm] peak by $H_{2}-CH_{4}$ plasma without by $N_2$ 337.1, 357.8 and 316.0[nm] peaks may be CH peak. In the investigation results for optical spectra by $H_{2}-CH_{4}$ plasma and $H_{2}-CH_{4}-O_{2}$ plasma, the density of hydrogen atom was increased because oxygen decompose hydrogen molecules in $H_{2}-CH_{4}$ plasma with oxygen. These hydrogen atom decompose $CH_4$ and increase CH radical. And the crystalline of deposited diamond was good and the growth rate increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.342-343
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• 2005

In this study,. the microwave dielectric properties of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics with sintering temperature were investigated for LTCC application. According to the X-ray diffraction patterns, the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics had columbite structure of the $TiTe_3O_8$ phase and scheelite structure of the $CaWO_4$ phase. Increasing the sintering temperature, the bulk density, the dielectric constant and the quality factor of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics were increased. In the case of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics sintered at $810^{\circ}C$, the bulk density, the dielectric constant and the quality factor were 5.72$g/cm^2$, 33.6, 22,013GHz respectively.

• Archives of Pharmacal Research
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• v.26 no.2
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• pp.107-113
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• 2003

Several fused triazolo and ditriazoloquinoxaline derivatives such as 1-aryl-4-chloro-[1,2,4]triazolo[4,3-a]quinoxalines (3a-d), 4-alkoxy[1,2,4]triazolo[4,3-a]quinoxalines (4a,b), 4-substituted-amino-[1,2,4] triazolo[4,3-a]quinoxalines (5a-h), 1-(aryl)-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-thione (6), 4-(arylidenehydrazino )-1-phenyl-[1,2,4]triazolo[4,3-a]quinoxalines (10a-e) and [1,2,4]ditriazolo[4,3-a:3',4'-c]quinoxaline derivatives (11-13) have been synthesized and some of these derivatives were evaluated for antimicrobial and antifungal activity in vitro. It was found that compounds 3a and 9b possess potent antibacterial activity compared to the standard tetracycline.