• Korean Journal of Optics and Photonics
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• v.5 no.4
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• pp.499-504
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• 1994

Ti-doped BSG (borosilicate glass) soot films on the silicone substrate have been deposited in the mixture of $SiCl_{4}$, TMB, $TiCL_{4}$ by flame hydrolysis deposition technique. The soot films are melted to form integrated fine glass films. We can fabricate thick films of serveral $10{\mu}m$ with deposition rate,more than $0.5{\mu}m$/min. Refractive index difference of BSG films are increased to more than 0.3% as function of the amount of Ti dopant. As a result of the process an optical waveguide which is simmilar with dimmension and refractive difference of optical fiber is produced. $BCl_{3}$ is widely used for B dopant, but we abtained the good results by the use of TMB in place of $BCl_{3}$. The melting point of silica soot glass is reduced to $1200^{\circ}C$ increasing B dopant. From FTIR analysis $B_2O_3$ content up to about lOmol% in BSG films. films.

• Electrical & Electronic Materials
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• v.10 no.5
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• pp.440-446
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• 1997

This research has been performed for the fabrication of high quality ferrite plastic magnet. The magnetic properties of S $r_{5.9}$F $e_2$ $O_3$ ferrite bonded magnets by injection moulding with a variety of applied magnetic field were investigated. 0.3wt% CaCO3, 0.2wt% $SiO_2$, 0.5wt% $Al_2$ $O_3$and 0.5wt% N $a_2$ $SiO_3$are added in order to improve the magnetic properties of Sr-ferrite plastic magnets during the powder fabrication. For carbon coating on chemical compound specimen, 5wt% polyvinyl alcohol is added, and then calcinated under $N_2$ environment of 12$25^{\circ}C$. The particle size is distributed from 0.9~1.2${\mu}{\textrm}{m}$ which approximates to the single domain. The obtained Sr ferrite powder is well mixed with silane coupling and calcium stearate of 1wt%. Nest, the specimen is pelleted after kneading each of them with polyamidel2 as a binder. When the temperature of injection and mould were 25$0^{\circ}C$ and 8$0^{\circ}C$ respectively at injection pressure of 200kgf/$\textrm{cm}^2$, the degree of orientation was 85.3% under the applied magnetic field of 12kOe. As the results, when the packing density of Sr ferrite powder was 90wt%, the magnetic properties of Sr ferrite bonded magnet were follows : $_{B}$ $H_{c}$=2.41kOe, Br=3.1kG, (BH)$_{max}$=2.21MgOe. Especially, the Sr-ferrite bonded magnet with 10wt% N $d_2$F $e_{14}$B additive were as follows : $_{B}$ $H_{c}$=2.57kOe, Br=3.14kG and (BH)$_{max}$=2.39MGOe.GOe.GOe.GOe.e.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.93-97
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• 2003

We describe here the cloning of a cDNA encoding putative calreticulin (CRT) from the silkworm, Bombyx mori. The CRT cDNA comprised of 1,194 bp encoding 398 amino acid residues. B. mori. CRT has a HDEL sequence at the end of the C-domain. The B. morl, CRT showed 88% protein sequence identity to the G. mellonella CRT, 71 % to A. aegypti CRT, and 63% to H. sapiens CRT, Phylogenetic analysis revealed that the deduced amino acid sequences of the B. mori CRT formed a highly inclusive subgroup with other insect CRTs. Northern blot analysis exhibited an expression of the B. mori CRT gene in the fat body, evidencing the fat body as a major site for CRT synthesis.

• Culinary science and hospitality research
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• v.12 no.4 s.31
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• pp.284-298
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• 2006

This study aimed at defining radish cultivars to a best cooking usage based on their physiochemical and textural characteristics of Nabakkimchi. Baekkwang, Daeburyong, Chungwoon and Taebaek were used as four types of radish cultivars. Nabakkimchi was stored at $8^{\circ}C$ either after fermentation for 12 hours at $25^{\circ}C$(A group) or without preliminary fermentation(B group). As storage period went by, lightness was decreased. Haziness of liquid showed sudden increase at preliminary fermentation in group A, while it increased between the third day and fifth day in group B. Hardness of 'Fall season' type was relatively high after storage. pH was suddenly decreased on the second day in A group and on the fifth day in B group. Acidity was suddenly increased on the second day in A group and since the third day at B group. As a result of sensory evaluation, Chungwoon stored for 2 days after preliminary fermentation was the best variety.

• Economic and Environmental Geology
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• v.5 no.2
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• pp.77-86
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• 1972

The system NaAlSiO_4-KAlSiO_4-SiO_2-H_2O, Bowen's "Petrogeny's Residua System" of course is extremely important in understanding the phase relationships of igneous and metamorphic rock in the continental crust. The phase relationships in this system, however, have not been completely established in the P-T range above the Mohorovicic discontinuity. They need to be established. In this study, the most probable sequence of P-T curves around a quaternary invariant point(~5Kb/${\sim}635^{\circ}C$) in the system using Schreinemakers' rule, is deduced, essentially on the basis of Morse's(1969a and b) experimental data. Possible modifications of the sequence of the P-T curves considering likely changes of the invariant chemogram are also considered. It is concluded that the sequence of P-T curves around the invariant point (~5Kb/${\sim}635^{\circ}C$) is (L), (Anl), (Or), (V), (Ne) and (Ab) on the P-T projection, where the P-T curve (L) is extended towards lower P-T regions, and the (Anl) curve is extended towards a region of higher temperature and lower pressure from the invariant point respectively.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.105-111
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• 1999

When the preparation method of iron silicide films possess the annealing process, the interfacial state of the films is not fine. The good quality films were obtained as the plasma was used without annealing processing. Since the injected precursors were various active species in the plasma state, the organic compound was contained in the prepared films. We confirmed the formation of Fe-Si bonds as well as the organic compound by Fe and Si vibration mode in Raman scattering spectrum at $250cm^{-1}$ and Ft-IR. Because of epitaxy growth being progressed by the high energy of plasma at the low temperature of substrate, iron silicide was epitaxially grown to ${\beta}$-phase that had lattice structure such as [220]/[202] and [115]. Band gap of the prepared films had value of 1.182~1.174 eV and optical gap energy was shown value of 3.4~3.7 eV. The Urbach tail and the sub-band-gap absorptions were appeared by organic compound in films. We knew that the prepared films by plasma were obtained a good quality films because of being grown single crystal.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.438-445
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• 2002

In this study, the glass frit of $PbO-TiO-2-SiO_2-BaO-ZnO-Al_2O-3-CaO-B_2O_3-Bi_2O_3-MgO$ system was manufactured. The glass was melted at $1,400{\circ}C$, quenched and attrition-milled. The glass frit powder was pressed and fired for 2h at the range of $750~1,000{\circ}C$. The crystallization of glass frit began at about $750{\circ}$ and at low temperature, the main crystal phases were hexagonal celsian($BaAl_2Si_2O_8$) and alumina. As the firing temperature increased, the crystal phases of monoclinic celsian, zinc aluminate, zinc silicate, calcium titanium silicate and titania appeared. And the increase of firing temperature led to transformation of hexagonal celsian to monoclinic. The only glass frit containing 15wt% PbO had the crystal phase of solid solution of $PbTiO_3-CaTiO_3$. At the frequency of 1 MHz, the dielectric constant of glass frit crystallized was in the range of 11~16 and the dielectric loss less than 0.020. But the glass frit containing 15wt% PbO had the dielectric constant of 17~26 and loss of 0.010~0.015 because of crystal phase of solid solution of $PbTiO_3-CaTiO_3$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.149-163
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• 2004

Evapotranspiration (ET) is a critical component of the hydrologic cycle which influences economic activities as well as the natural ecosystem. While there have been numerous studies on ET estimation for homogeneous areas using point measurements of meteorological variables, monitoring of spatial ET has not been possible at landscape - or watershed - scales. We propose a site-specific application of the land surface model, which is enabled by spatially interpolated input data at the desired resolution. Gyunggi Province of South Korea was divided into a regular grid of 10 million cells with 30m spacing and hourly temperature, humidity, wind, precipitation and solar irradiance were estimated for each grid cell by spatial interpolation of synoptic weather data. Topoclimatology models were used to accommodate effects of topography in a spatial interpolation procedure, including cold air drainage on nocturnal temperature and solar irradiance on daytime temperature. Satellite remote sensing data were used to classify the vegetation type of each grid cell, and corresponding spatial attributes including soil texture, canopy structure, and phenological features were identified. All data were fed into a standalone version of SiB2(Simple Biosphere Model 2) to simulate latent heat flux at each grid cell. A computer program was written for data management in the cell - based SiB2 operation such as extracting input data for SiB2 from grid matrices and recombining the output data back to the grid format. ET estimates at selected grid cells were validated against the actual measurement of latent heat fluxes by eddy covariance measurement. We applied this system to obtain the spatial ET of the study area on a continuous basis for the 2001-2003 period. The results showed a strong feasibility of using spatial - data driven land surface models for operational monitoring of regional ET.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.277-281
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• 2003

Effects of $CaF_2$ addition as a filler on the high frequency dielectric properties and sintering of CaO-$Al_2O_3-SiO_2-B_2O_3$(CASB) and ZnO-MgO-$B_2O_3-SiO_2$(ZMBS) glass composites were investigated. The optimal glass composition in the CASB system was 33.0CaO-$17.0Al_2O_3-35.0SiO_2-15.0B_O_3$(in wt%). The corresponding dielectric properties were k=8.1 and $Q{\times}fo$=1,200GHz. The sintering temperature was $800{\mu}m$. In case of 2MBS system, 25.0ZnO-25.0MgO-20.0$B_2O_3-30.0SiO_2$(in wt%) glass showed k=6.8 and $Q{\times}fo$=5,200GHz when it was sintered at $750^{\circ}C$. The maximum amount of $CaF_2$ in the CASB and 2MBS glass system without any detrimental effect on the sintering was 25.0 v/o and 15.0 v/o, respectively. The addition of $CaF_2$ in the glass systems improved the high frequency dielectric properties. In case of CASB+$CaF_2$ composite, k was 7.1 and $Q{\times}fo$ was 2,300GHz. And in case of 2MBS+$CaF_2$ composite, k was 5.9 and $Q{\times}fo$ was 8,100GHz. $CaF_2$ addition also reduced sintering temperature. Effects of $CaF_2$ on the dielectric and sintering properties was analyzed in terms of viscosity and crystallization behavior changes due to the interaction between $CaF_2$ and the glass systems.

• Journal of the Korean Ceramic Society
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• v.26 no.6
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• pp.771-782
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• 1989

Synthesis of $\beta$-Sialon powder was attempted with carbothermal reduction of porous glass. The porous glass was prepared by heat and hydrothermal treatments of 9.32 Li2O.46.5B2O3.37.2SiO2.6.98Al2O3 glass. Carbon pyrolyzed from propane gas was deposited on the porous glass, thereafter activated carbon was added as reducing agents. The synthesized $\beta$-Sialon powder was pressureless sintered at 175$0^{\circ}C$ for 1hr in N2 atmosphere. The characterization of the $\beta$-Sialon powder was performed with XRD, BET, SEM and particle size analysis. The sinterability and mechanical properties of the sintered bodies were investigated in terms of bulk density, M.O.R., fracture toughness, morphology of microstructure and etc. The reduction effect of deposited carbon was better than that of activated carbon mechanically added. The formation of SiC was precominant over that of Si2ON2 and $\beta$-Sialon owing to low partial pressure of N2 inside the pore, wehreas on the surface of porous glass the formation of Si2ON2 and $\beta$-Sialon were predominant. Thereafter, SiC reduced unreacted glass to be $\beta$-Sialon. Single phase of $\beta$-Sialon(Z=1.92) was obtained from PGA porous glass having the largest pore radius by the simultaneous reduction and nitridation method at 145$0^{\circ}C$ for 5hrs. The bulk density, M.O.R., and KIC of the sitered body are 3.17g/cc, 434.4MPa and 4.1MPa.m1/2, respectively.