• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.243-246
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• 2003

Poly(butylene terephthalate)(PBT) is an important engineering polyester. It crystallizes much more easily and faster than PET. And these crystallization properties determine its use as an injection molding resin. Although it is more extensive than PET, its crystallization can be controlled much more easily during processing. General electric (Schenectady, NY) is the main producer of PBT films. Its production capacity was 3-5million pounds per year in 1987. (omitted)

• Rapid Communication in Photoscience
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• v.1 no.1
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• pp.11-12
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• 2012

The naphthalic amide derivatives were synthesized by simple condensation and were crystallized by acetonitrile solution. The SEM images of products with methyl group and nitro group, respectively, showed rod shape while the SEM images of products with other groups ($N(CH_3)_2$, $OCH_3$, H, F, and Cl), respectively, showed plate shape. We were known from these results that the substituent of ending group played an important role in the crystallization of single molecule and the morphology of naphthalic derivatives could be controlled by only change of ending group in single molecule.

• Journal of the Korean earth science society
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• v.36 no.5
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• pp.447-459
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• 2015

Dok island comprises Pliocene volcanic products such as a series of volcanoclastic rocks and lavas ranging in composition from alkali basalts, and trachyandesites to trachytes. Compositional variation of the basaltic rocks can be attributed to fractional crystallization of olivine, clinopyroxene, plagioclase, and magnetite. Chemical variations among the trachyandesites are caused by fractionation of clinopyroxene, plagioclase, and magnetite with minor amphibole, while trachytes are controlled mainly by feldspar fractionation. Incompatible element abundance ratios and chondrite normalized LREE/HREE ratios (e.g., (La/Yb)c: 24.8 to 32.8 for basalts, 15.6 to 31.2 for trachyandesites) suggest that the origins of the basalts and trachyandesites involve both different degrees of partial melting and subsequent fractional crystallization processes. Trace element ratios of the basalts from Dok island are characterized by high Ba/Nb, La/Nb, Ba/Th and Th/U and isotopic ratios (Tasumoto and Nakamura, 1991) that are similar to the EM 1 type of oceanic island basalts such as Gough and Tristan da Cunha basalts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.133-135
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• 2006

SBN60 and SBN60/30 thin films were deposited by ion beam sputtering technique. Using the ceramic target of the same composition and Pt(100)/$TiO_2$/$SiO_2$/Si or Pt(111)/Ti/$SiO_2$/Si substrate, crystallization and orientation behavior as well as electric properties of the films were examined, Thickness was controlled to $3000{\AA}$ and the films were heat-treated at $650^{\circ}C{\sim}800^{\circ}C$. The orientation and crystallization behavior were observed which showed the dependence on processing condition($O_2$/Ar ratio, substrate temp, annealing temp...).

• Journal of the Korean Ceramic Society
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• v.17 no.1
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• pp.27-34
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• 1980

The synthesis of glass-ceramic materials from glasses based on industrial wastes or natural rocks their physical properties were studied. Glasses of composition, CaO14.7∼16.1, MgO7.4∼9.0, Al2O38.3∼19.3, SiO2 48.9∼51.0wt% were prepared from domestic blast furnace slag, serpentine, sea sand and etc. with additions of chromic oxide, and fluoride as nucleating agent. The glasses were subjected to controlled heat treatments and yielded fine microstructure of glass-ceramics which were composed of monocrystalline phase of aluminous diopside. X-ray diffraction techniques were adopted to identify the crystalline phases and to determine the degree of crystallization quantitatively. Density, coefficient of thermal expansion, young's modulus, microhardness and modulus of rupture were measured and the resulting properties were discussed in terms of the heat-treatment conditions, the degree of crystallization, species of crystaline phase, the microstructures formed in glass-cramics and the chemical compositions of mother glasses.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.247-256
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• 2000

Precursor gels with the composition of $xZrO_2{\cdot}(100-x)SiO_2$ systems (x=10, 20 and 30 mol%) were prepared by the sol-gel method. Kinetic parameters, such as activation energy, Avrami's exponent, n, and dimensionality crystal growth value, m, have been simultaneously calculated from the DTA data using Kissinger and Matusita equations. The crystallite size dependence on tetragonal to monoclinic transformation of $ZrO_2$ was investigated using XRD, in relation to the fracture toughness. The crystallization of tetragonal $ZrO_2$ occurred through 3-dimensional diffusion controlled growth(n=m=2) and the activation energy for crystallization was calculated using Kissinger and Matusita equations, as about $310{\sim}325{\pm}10kJ/mol$. The growth of $t-ZrO_2$, in proportion to the cube of radius, increased with increasing heating temperature and heat-treatment time. It was suggested that the diffusion of Zr4+ions by Ostwald ripening was rate-limiting process for the growth of $t-ZrO_2$ crystallite size. The fracture toughness of $xZrO_2{\cdot}(100-x)SiO_2$ systems glass ceramics increased with increasing crystallite size of $t-ZrO_2$. The fracture toughness of $30ZrO_2{\cdot}70SiO_2$ system glass ceramics heated at $1,100^{\circ}C$ for 5 h was $4.84Mpam^{1/2}$ at a critical crystaliite size of 40 nm.

• YAKHAK HOEJI
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• v.41 no.3
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• pp.305-311
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• 1997

Sustained release-microspheres and immediate release-pellets were prepared to develop a controlled release multiparticulate system containing both water soluble and insoluble dr ug. Pseudoephedrin.HCl (EPD) and terfenadine (TRF) were used as model drugs, respectively. Sustained release-EPD microspheres were prepared by solvent evaporation method using Eudragit RL or RS as a matrix combined with pH-insensitive film coating. Smaller EPD microspheres were obtained when smaller amount of Eudragit as a matrix material or larger amount of magnesium stearate as a dispersing agent was used. However the obtained microspheres did not show syfficient sustained release characteristics. About 97% of EPD was released after 1 hr irrespective of matrix material used. Subsequent coating of the microspheres with pH-insensitive polymer such as Eudragit RS or ethylcelulose (EC) resulted good sustained in 37.5, 73.3 and 92.0% release of encapsulated EPD in distilled water after 1, 3 abd 7 hr, respectively. It corresponds to mean dissolution time (MDT) of 2.3 hr, which is much larger than that of un-coated EPD microspheres (0.0048 hr). Immediate release TRF pellets were prepared by spherically agglomerated crystallization using Eudragit E as an inert matrix and methylene chloride as a liquid binder. Using Eudragit E alone as a matrix resulted in satisfactory physical properties of the pellets such as sphericity, surface texture and flowability, but led to slower release of TRF from pellets than un-modified TRF powder (MDT of 1.70 vs 1.43 hr in pH 1.2 dissolution medium). Introducing propylene glycol or sodium lauryl sulfate as an emulsifier brought about faster release of TRF from pellets (MDT of 1.14 and 0.95 hr, respectively). In conclusion, microencapsulation by solvent evaporation combined with film coating and spherically agglomerated crystallization were successfully utilized to prepare controlled release multiparticulate system composed of sustained release EPD-microspheres and immediate release TRF pellets.

• Journal of the Korean Vacuum Society
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• v.16 no.2
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• pp.116-121
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• 2007

TiNi shape memory alloy(SMA) was fabricated by PLD(plused laser deposition) using equiatomic TiNi target. Composition and crystallization of TiNi thin films which were fabricated in ambient Ar gas(200m Torr)and vacuum($5{\times}10^{-6}\;Torr$) were investigated. Composition of TiNi thin films was characterized by energy-dispersive X-ray spectrometry (EDXS) and crystallization was confirmed by X-ray diffraction (XRD). The composition of films depends on the distance between target and substrate but does not sensitively depend on the substrate temperature. It is found that the composition of films can be easily controlled when substrate is placed inside plume in ambient Ar gas. It is also found that the in situ crystallization temperature ($ca.\;400^{\circ}C$) in ambient Ar gas is lowered in comparison with that of TiNi film prepared under vacuum. The low crystallization temperature in ambient Ar gas makes it possible to prepare the crystalline TiNi thin film without contamination.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.997-1000
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• 2001

Pb(Zr$\sub$0.52/Ti$\sub$0.48/)O$_3$(PZT) thin films have been prepared by rf-magnetron sputtering methods and investigated the structural and electrical properties. In order to investigate the effects of sputtering conditions, input power was controlled during deposition. Crystallization process and microstructure of PZT thin films were largely affected by input power. Highly crystallized PZT films with the perovskite structure were successfully obtained on Pt/Ti bottom electrode. The dielectric constants and polarization of PZT thin films were increased with increasing input power, and the coercive electric field was decreased with increasing input power . The dielectric constant of PZT thin films with input power 150 W was 966 at 1 kHz. we, authors, proposed that preferred orientation of PZT thin films were controlled by input power in sputtering methods.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.768-771
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• 2006

Uniformity and performance characteristics of LTPS TFTs are important parameters for making advanced active-matrix displays. In this paper, we describe an SLS-based crystallization approach for producing orientation-controlled Si films with reduced concentrations of planar defects that stand to potentially deliver unprecedented levels of device uniformity and performance. Specifically, a 2-step process referred to as hybrid SLS has been developed that produces a variety of high-quality {100} surface-oriented Si films.