• 한국초전도학회:학술대회논문집
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• v.13
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• pp.64-64
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• 2003

• Korean Journal of Microbiology
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• v.19 no.3
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• pp.115-120
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• 1981

The substance produced by Bacillus subtilis $480HS_{20}$ showed specific anti Puccinia graminis activity and narrow antimicrobial activity. The anti Puccinia graminis substance was found to be peptide antibiotic which had molecular weight of about 1,500 by sephadex LH-60 gel-filtration. The amino acid composition of the substance waas composed of Ser (1), Glu(3), Ile(1), Gyr(2) and His (1). The compound was yellowish powder and it's melting point was $214{\sim}216^{\circ}C$. UV spectrum in methanol showed single peak at 278(E 1% 1cm 15.2) and important peak at 3,350-3,320, 2,940, 1,635, 1,520-155, 1,240-1, $230cm^{-1}$ were observed in IR Spectrum. The substance was soluble in methanol but insoluble in water, ethyl acetate and chloroform. The antibiotic $480HS_{20}$ showed a little antimicrobial activity against Pyricularia aryzae but no antimicrobial activity was observed against Gram + and Gram - bacteria and molds except pyricularia oryzae.

• Journal of the Korean Ceramic Society
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• v.30 no.6
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• pp.429-432
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• 1993

Cr3C2 material is characterized by high chemical stability and poor sinterability with low strength [50~150MPa]. In his study, low melting temperature nickel powder was used to improve sinterability as well as strength. In addition, molydenum particles were added to the Ni-bonded Cr3C2 cermet pseudomatrix to increase resistance to fracture. The specimens made by hot-pressing under vacuum and strength was measured by 4-point bending. Indentation cracking and fractographic examination were conducted to study the interaction of the indentation cracks with the reinforcing particles. Toughening mechanisms and failure will be discussed in terms of crack/particle interactions and compared with previous works.

• Journal of the Korean Ceramic Society
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• v.34 no.11
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• pp.1182-1186
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• 1997

La0.8Ca0.2Cr0.98O3 powder was prepared using the modified Pechini process. Various crystalline phases formed during thermal decomposition were investigated. (La,Ca)CrO4 phase, first formed from the precursor, was transformed to (La,Ca)CrO3 and CaCrO4 above 80$0^{\circ}C$, which remained up to 110$0^{\circ}C$. However, only (La,Ca)CrO3 phase consisting of orthorhombic and intermediate rhombohedral polymorphs was observed after sintering at 125$0^{\circ}C$. The specimens sintered at 140$0^{\circ}C$ exhibited 98% of relative density and rather wide grain size distribution with average grain size of 3-4 ${\mu}{\textrm}{m}$. Densification and grain growth of the specimens observed above 125$0^{\circ}C$ were presumably attributed to liquid phase sintering resulted from melting of Ca3(CrO4)2 phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.478-481
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• 2002

We carried out the experiments for fabricating $Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{x}$(Bi2223) superconductor thick films on Cu tapes. Cu-free (Bi,Pb)-Sr-Ca-0 powder mixtures were screen- printed on Cu tapes and heat-treated at 840-$860^{\circ}C$ for several minutes in air. Surface microstructures and phases of films were analyzed by XRD and optical microscope. The electric properties of superconducting films were examined by the four probe method. At heat-treatment temperature, the printing layers were in a partially molten state by liquid reaction between CuO in the oxidized copper tape and the precursors which were printed on Cu tapes. During the heat-treatment procedure, it is thought that Bi2223 superconducting particles nucleate at interfaces between Bi2212 phase and liquid.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1832-1835
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• 2003

This paper suggests the selective ultra precision polishing techniques for micro die and mold parts using magnetic-assisted machining. Fabrication of magnetic abrasive particle and their polishing performance are key technology at ultra precision polishing process of micro parts. Conventional magnetic abrasives have disadvantages. which are missing of abrasive particle and inequality between magnetic particle and abrasive particle. So, bonded magnetic abrasive particles are fabricated by several method. For example, plasma melting and direct bonding. Ferrite and carbonyl iron powder are used as magnetic particle where silicon carbide and Al$_2$O$_3$ are abrasive particle. Developed particles are analyzed using measurement device such as SEM. Possibility of magnetic abrasive and polishing performance of this magnetic abrasive particles also have been investigated. After polishing, surface roughness of workpiece is reduced from 2.927 $\mu\textrm{m}$ Rmax to 0.453 $\mu\textrm{m}$ Rmax.

• Korean Journal Plant Pathology
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• v.13 no.1
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• pp.63-68
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• 1997

In the screening of antiviral materials produced by actinomycetes, an isolate named B25 was fond to produce an antibiotic substance ASA, which showed a strong inhibitory activity against tobacco mosaic virus (TMV) infection. ASA was purified from culture broth of B25 by silica gel column chromatography, preparative TLC, and reversed phase HPLC. Also MS, IR, UV spectrum, and melting point of ASA were determined and analysed. ASA was white powder soluble in dimethyl sulfoxide, chloroform, and ethyl acetate, having absorption peaks at 223 and 328 nm in UV-VIS spectrum, and had a molecular weight of 548. ASA showed strong inhibitory effect on TMV infection when it was applied as a mixture of TMV to the upper surface of leaves of a local lesion host (Nicotiana tabacum c. Xanthi-nc). It also showed antimicrobial effect against yeast and some phytopathogenic fungi.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.801-804
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• 2000

High-temperature superconductor of Bi-2212 system was fabricated by CFP(Centrifugal Forming Process). To make a uniform specimen slurry was prepared in the ratio of 7:3(powder : binder) and ball milled for 24 hours. Milled slurry was charged into a rotating mold with 450 rpm and dried at room temperature. Then the specimen was performed binder burn-out at 35$0^{\circ}C$ and heated for partial melting to 86$0^{\circ}C$. XRD analysis of most specimens were shown 2212 phase and observed a local plate shped microstructure with a well aligned c-axis direction from SEM images. Measured T$_{c}$(Critical temperature) was about 64 K.K.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.90-90
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• 2017

Cold spray (Cold gas dynamic spray, kinetic spray) is the latest spray coating process that is known as solid state deposition process. In cold spray, inert gases (typically nitrogen and helium) accelerate powder particles prior to impact onto the substrate. Accelerating particles start to deposit onto the substrate after reaching certain critical velocities depending on the coating materials and substrate. Since process gas temperatures are kept below to melting temperature of the coating materials, it is possible to spray temperature sensitive materials such as copper and titanium, nanocrystal materials, and amorphous metals without affecting the phase change and oxide formation. It is also possible to deposit thick coatings because cold spray coatings present compressive residual stresses. This ability to deposit thick coatings is suitable to repair or rebuild parts as an additive manufacturing process. In this presentation, cold spray is introduced and compared to other additive manufacturing processes such as laser and electron beam based processes. It is also presented some applications especially in the view point of additive manufacturing process.

• Journal of the Korean Society of Food Culture
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• v.26 no.3
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• pp.279-282
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• 2011

We evaluated the sensory characteristics of Gangjung base obtained from various manufacturers, using a sensory descriptive analysis. Significant differences were observed for all sensory attributes of Gangjung samples with the exception of 'toothpacking'. Sample A showed high intensities for 'external color', 'external roughness', 'sweetness', 'toasted soybean powder flavor', 'crispness', 'fracturability', 'oiliness', and 'loose particles,' whereas it had low intensities for 'rice flour flavor', 'hardness', and 'toughness' compared to those of other samples. Sample B had more 'sourness', 'butyric acid flavor', 'fermented rice flavor', and 'degree of melting' but lower 'air cell size', 'fracturability', and 'flake roughness'. Sample C showed high intensities for 'expansion', 'hardness', 'crispness', and 'flake roughness', whereas sample D showed low intensities for 'expansion' and 'sourness'. These results indicate that Gangjung base samples are markedly different depending on the manufacturer.