• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.243-245
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• 2009

The single phase $Ba_2SiS_4$ doped with $Eu^{2+}$ was successfully synthesized by direct sulfurization of an oxide precursor prepared by a spray drying method using a novel water soluble silicon compound, which remains soluble in a given aqueous solution. The intensity of the emission peak of thus obtained $Ba_2SiS_4:Eu^{2+}$ was 1.75 times larger than that of a sample prepared by a solid state reaction method, and it approached 106% compared to one of the best commercially available YAG:$Ce^{3+}$ phosphor.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.529-533
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• 1996

Melittin (ME) from honeybee venom has a broad range of strong antimicrobial activity, but it has hemolytic activity against eukaryotic cells. In order to design peptides with powerful antifungal activity without cytotoxic property of ME and understand structure-antifungal activity relationships, the hybrid peptides derived from the sequences of ME and cecropin A (CA) or magainin 2 (MA), MA(10-17)ME(1-12) and CA(1-8)ME(1-12). were synthesized by solid phase method. MA(10-17)ME(1-12) showed potent antifungal activity comparable to ME against Fusarium oxysporum with no hemolytic activity against human red blood cells. The hybrid peptides showed strong inhibi- tion of (1, 3)-$\beta$-D-glucan synthase. This result indicates that the antifungal activity of the hybrid peptides against Fusarium oxysporum is attributed to the inhibition of cell wall synthesis. The results therefore showed a successful design of a peptide having antifungal activity without hemolytic property.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.394-398
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• 1988

Unusually high reactivity was found in peptide bond formation between p-nitrobenzophenone oxime resin (I) ester and amino acid 4-(methylthio)phentyl (MTP) esters. A charge-transfer complex between the two phenyl rings of the oxime resin (I) and the incoming amino acid MTP esters was considered to be responsible to accelerate the aminolysis reaction of the peptide oxime resin ester. Several di-, tri-, and pentapeptide fragments for preparing enkephalin and glutathione oligomers were successfully prepared in short times.

• Bulletin of the Korean Chemical Society
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• v.20 no.9
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• pp.1073-1077
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• 1999

CRAMP, a 37-amino acid cationic antimicrobial peptide was recently deduced from the cDNA cloned from mouse femoral marrow RNA. In order to investigate the structure-activity relationship and functional region of CRAMP, CRAMP and its 18-mer overlapping peptides were synthesized by the solid phase method. CRAMP showed broad spectrum antibacterial activity against both Gram-positive and Gram-negative bacterial strains (MIC: 3.125-6.25 μM) but had no hemolytic activity until 50 μM. CRAMP was found to have a potent anticancer activity (IC50: 12-23 μM) against two human small cell lung cancer cell lines. Furthermore, CRAMP was found to display faster bactericidal rate in B. subtilis rather than E. coli in the kinetics of bacterial killing. Among 18-meric overlapping fragment peptides, only CRAMP (16-33) displayed potent antibacterial activity (MIC: 12.5-50 μM) against several bacteria with no hemolytic activity. Circular dichroism (CD) spectra anal-ysis indicated that CRAMP and its analogues will form the amphipathic α-helical conformation in the cell membranes similar to other antimicrobial peptides, such as cecropins and magainins.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.23-23
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• 2009

Recently, the nanowire configuration of GST showed nanosecond-level phase switch at very low power dissipation, suggesting that the nanowires could be ideal for data storage devices. In spite of many advantages of IST materials, their feasibility in both thin films and nanowires for electronic memories has not been extensively investigated. The synthesis of the chalcogenide nanowires was mainly preformed via a vapor transport process such as vapor-liquid-solid (VLS) growth at a high temperature. However, in this study, IST nanowires as well as thin films were prepared at a low temperature (${\sim}250^{\circ}C$) by metal organic chemical vapor deposition(MOCVD) method, which is possible for large area deposition. The IST films and/or nanowires were selectively grown by a control of working pressure at a constant growth temperature by MOCVD. In-Sb-Te NWs will be good candidate materials for high density PRAM applications. And MOCVD system is powerful for applying ultra scale integration cell.

• Journal of Powder Materials
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• v.16 no.5
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• pp.310-315
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• 2009

Ultra-fine TiC/Co composite powder was synthesized by the carbothermal reduction process without wet chemical processing. The starting powder was prepared by milling of titanium dioxide and cobalt oxalate powders followed by subsequent calcination to have a target composition of TiC-15 wt.%Co. The prepared oxide powder was mixed again with carbon black, and this mixture was then heat-treated under flowing argon atmosphere. The changes in the phase, mass and particle size of the mixture during heat treatment were investigated using XRD, TG-DTA and SEM. The synthesized oxide powder after heat treatment at 700$^{\circ}C$ has a mixed phase of TiO$_2$ and CoTiO$_3$ phases. This composite oxide powder was carbothermally reduced to TiC/Co composite powder by the solid carbon. The synthesized TiC/Co composite powder at 1300$^{\circ}C$ for 9 hours has particle size of under about 0.4 $\mu$m.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1326-1329
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• 1997

In this paper, PNN-PZN-PZT ceramics were fabricated with various mole ratio of the PZT[$Pb(Zr_{1/2}Tid_{1/2})O_3$]. PNN [$Pb(Ni_{1/3}Nb_{2/3})O_3$] and PZN[$Pb(Ni_{1/3}Nb_{2/3})O_3$ powders prepared by double calcination and PZT powders prepared by molten-salt synthesis method. The formation rate of perovskite phase in PNN-PZN-PZT ceramics could be obtained about 92% at PZT 0.3 mole ratio. The relative permittivity of specimen with PZT 0.3 mole ratio was shown 5,320 and appeared the relaxor ferroelectric feature. The maximum piezoelectric coefficient $d_{31}$ to be used for evaluation the displacement of piezoceramics in PNN-PZN-PZT ceramics was $324{\times}10^{-12}$(C/V) at the vicinity of morphotropic phase boundary and was larger than that of solid PZT ceramics($120{\times}10^{-12}C/V$).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.271-274
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• 1998

Metallic ferromagnet LA$_{1-x}$ Sr$_{x}$MnO$_3$ has received considerable attentions because of its metallic conductivity and giant magnetic resistivity. It is generally believed that layered perovskite SrO(LA$_{1-x}$ Sr$_{x}$MnO$_3$)$_{n}$ phase is insulating and shows no metallic transition. But recent report revealed that some single crystal SrO(LA$_{1-x}$ Sr$_{x}$MnO$_3$)$_{n}$ phase showed MR effect. In this study, layered perovskite SrO(LA$_{1-x}$ Sr$_{x}$MnO$_3$)$_2$ Phases were synthesized by solid state reaction at 140$0^{\circ}C$ in air atmosphere, for wide range of x and their phases were confirmed by X-ray diffraction. Electrical and magnetic properties were measured down to 10K and the possibility of MR effects was investigated.as investigated.

• Progress in Superconductivity and Cryogenics
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• v.20 no.3
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• pp.1-4
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• 2018

The effect of sulfate substitution on the formation of (Pb,S)-1201 type phase was investigated. Polycrystalline samples with nominal compositions of $(Pb_{0.5}B_{0.5-x}S_x)(Sr_{2-y}La_y)CuO_z$, (x = 0 - 0.5, y = 0.7 - 1.0) and $(Pb_{0.5}S_{0.5})(Sr_{2-y}La_y)CuO_z$ (y = 0.5 - 1.0) were prepared by using a solid-state reaction method. The samples were characterized by powder X-ray diffraction (XRD) and resistivity measurements. XRD data revealed that almost-single (Pb,S)-1201 phase samples could be obtained for x = 0.5 and y = 0.9-1.0, judging from the similar results of the XRD patterns between the (Pb,S)-1201 and (Pb,B)-1201 phases. Each of the samples has a crystal structure with tetragonal symmetry. The sample with x = 0.5 and y = 0.9 is found to show an onset of resistivity dropping at over 23 K and zero resistivity at 12 K.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.8-12
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• 1994

Solid solutions $Sr_2$($Ta_{1-x}$$Nb_{x}$)$_2$$O_{7}$ (x = 0.0 - 1.0) composed of strontium-tantalate (low Curie temperature) and strontium-niobate (high Curie temperature) were prepared by the conventional mixed oxide method and the molten salt synthesis method (flux method). Phase relation, sintering temperature, grain-orientation and dielectric properties were investigated for sintered ceramic samples with different compositions. Both Curie temperature and dielectric constant at Curie temperature were increased, and sintering behavior and the degree of grain-orientation were improved with the increase of Nb content. Single phase $Sr_2$$Nb_2$$O_{7}$ powder was synthesized by using flux method at lower temperatures, and sintering temperature was also reduced by using flux method derived powder than using mixed-oxide derived powder. Sintering characteristics and dielectric properties of specimens prepared by flux method were better than those derived through the conventional method.