• The Journal of the Petrological Society of Korea
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• v.6 no.3
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• pp.210-225
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• 1997

From their general natures of peraluminous, S-type and ilmenite-series granites, two-mica granites in the Cheongsan, Inje-Hongcheon, Yeongju and Namwon areas were originated from crust-derived granitic magma and solidified under reducing condition. Each two-mica granite in Inje-Hongcheon and Namwon districts was differentiated from the the residual magma of porphyric biotite granite and high Ti/Mg biotite granite, respectively. The genetic relationships between two-mica granite and porphyritic biotite granite in Chenongsan district and between two-mica granite and biotite granodiorite in Yeongju district are ambiguous. In Namwon district granitic magmas were water-saturated and possible water solubilities in magmas were more than 5.8wt.%. In Yeongju district two-mica granitic magma was nearly water-saturated and showed possible water solubilities between 2.4~5.8wt.%. Two-mica granitic magmas in Cheongsan and Inje-Hongcheon districts were water-undersaturated. Pressure-dependent minimum melt compositions (0.5~2kb) and petrographic textures of two-mica granites in Inje-Hongcheon and Yeongju districts represent that the granites intruded and solidified at shallow level, whereas those in Cheongsan and Namwon districts exhibit relatively deeper level of granitic intrusion (2-3kb). The intersection of granite-solidus/muscovite stability indicates that magmatic primary muscovite can be crystallized from the water-saturated magma above 1.6kb (ca. 6km), but below the pressure muscovite can be formed by the subsolidus reaction. On the other hand, more pressure would be necessary for the crystallization of primary muscovite from the water-undersaturated magma. This pressure condition can explain the occurrence of primary and secondary muscovites from the two-mica granites in the areas considered. The experimental muscovite stability must be cautious of the application to examine the origin of muscovite. The muscovite stability can move toward high temperature field with adding of Ti, Fe and Mg components to the octahedral site of pure muscovite end member.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.72-77
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• 1999

An antibody containing a genetically engineered lipid group at the N-termunus and a hexahistidinyl tag at the C-terminus (Lpp-scF-His6) was immobilized in an oriented manner on the surface of liposome. Liposomes, consisting of antibody and phosphatidyl-choline, have been prepared and imaged by AFM. For AFM visualization, the resulting liposomes were bound on the surface of mica by two different mechanisms. The histidine tags present in the antibody molecules of the immonuliposome were anchored to the NiCl2 treated mica surface. Alternatively, the immunoliposomes were immunochemically bound on antigen-coated mica surface. Both approaches yielded liposomes which were clearly imaged without damage by AFM in ambient condition.

• Economic and Environmental Geology
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• v.22 no.4
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• pp.315-326
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• 1989

The pottery stone diposits of the Cheongsong area consist of abundant quartz with clay minerals such as mica/smectite interstratified mineral, tosudite, kaolinite and sericite. The occurrence and mineralogical properties of the clay minerals were investigated by X-ray diffraction method, chemical analysis, DTA and IR. The mineral transformation by hydrothermal alteration was also discussed. Tosudite occurs in the Beopsoo pottery stone deposit, it seem to be Li-beraing tosudite. Mica/smectite interstratified minerals with less than about 20% expandable layers are commonly observed in the pottery stone deposits of the area. The mica/smectite interstratified minerals tend to increase the expandable layers as the progress of alteration. The pottery stones from this area seem to be altered from rhyolite or welded tuff by hydrothermal solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1151-1154
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• 2005

The size effects for adhesive and frictional characteristics were studied. The specimen was Mica and the AFM tips were SiO2. The radii of SiO2 tip were 280, 380, 930, and 2230 nm on which tribological tests had never been performed. It was found that the adhesive forces and the frictional coefficients increased non-linearly with tip radius. Compared with previous studies at nanoscale and microscale, the results showed behaviors bridging each previous result. It could be said that these results were clues to explain the material behaviors between nanoscale and microscale both in adhesion and friction.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.976-979
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• 1992

There are lots of problem which are delaminations and partial discharge of insulation materials in high-voltage rotating machines caused by mechanical, electrical and thermal aging. Several experiments have been aiming at finding the useful diagnostic parameters from the partial discharge characteristics by applying a new measurement techniques. This paper deals with the partial discharge characteristics (pulse height, pulse angle, pulse frequency spectrum and time interval), which may be a useful diagnostic concept in predicting insulation condition of mica/epoxy composite insulation materials, by using several measurement equipments (frequency spectrum analyzer. multichannel analyzer and time interval analyzer).

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.151-154
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• 1988

Mica glass ceramics are known for their good electrical, mechanical, and thermal properties. These materials are produced by appropriate heat treatment of a suitable glass composition. In this paper electrical properties of mica glass ceramics with fluorcphlogopite crystalline phase have been investigated. At frequency range 1kHz-10MHz dielectric constants fall in the range fran 7.5 to 8.5 with law dissipation factors(0.002-0.008)at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.330-333
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• 1997

The thermal impact of mica/epoxy paper(130${\mu}{\textrm}{m}$) is investigated using XRD, DSC and TGL X-ray diffraction(XRD) analysis was performed to know the position and structure of mica crystal in insulation materials. A differential scanning calorimeter(DSC) was used to measure glass transition temperature and excess enthalphy of the composite materials that had been subjected to thermal aging. The glass transition temperature(T$_{g}$) measured by DSC is observed at 95.43$^{\circ}C$ and 113.43$^{\circ}C$, respectively. The T$_{g}$ also increases with increased aging time. Measurements performed by TGA(thermogravimetric analysis) have showed that weight loss profile of sound specimens are lower than those aged.ged.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.326-329
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• 1997

The surface of mica/epoxy paper(130${\mu}{\textrm}{m}$) is investigated with SEM(scanning electron microscope). SEM micrographs revealed that thermal aging has a strong influence on aged specimens. The mica/epoxy paper was exposed at 187$^{\circ}C$ in an ordinary electrical oven for 72hour. Stater windings from two generators were measured by tan delta(tan $\delta$)and maximum partial discharge(Qm). The values of tan $\delta$and Qm were fecund to be higher for new generator than old one. The insulation condition of mica/epoxy paper were measured by ac current and tan $\delta$. Test results are observed that the sound specimens are higher than those aged. Model bar coils subjected to various accelerated agings were evaluated by Qm.

• Journal of the Korean Ceramic Society
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• v.29 no.10
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• pp.815-821
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• 1992

The batches having excess SiO2 to tetrasilicic mica KMg2.5 (Si4O10)F2 were melted at 1450℃. The fabricated samples were heat-treated for the nucleation and the crystallization. The crystallized samples were investigated on several properties. The tetrasilicic mica composition with excess 10 wt% SiO2 was successful both in glassifying and in crystallizing. The optimum temperatures for the nucleation and the crystallization were 680℃ and 1000-1100℃, respectively. The mica and the cristobalite crystallines were identified after heat-treatment. The properties of the samples processed appropriately were as follows, bulk density 2.64g/㎤, thermal expansion coefficient ∼80×10-7/℃, Vicker's hardness ∼105 Kgf/㎟, bending strength ∼666Kgf/㎟, dielectric constant ∼11.1, tan δ 2.5%, volume resistivity 2.35×107∼1.3×1011{{{{ OMEGA }}cm, surface roughness 6.984㎛.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1524-1526
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• 2000

Two stator windings for high voltage motor(rated 6.6kV) were manufactured with mica tape/varnish(No. 1). and mica tape(No. 2). Electrical tests included ac current, tan $\delta$ and partial discharge magnitude in these stator windings. Electrical properties showed that No. 1 stator winding was better than that of No. 2. Microstructure properties were conducted using scanning electron microscope(SEM) in the cross section of the straight stator windings. SEM results indicated that the mica tape interface of No. 1 stator winding was larger than that of No. 2 stator winding.