• Journal of Industrial Technology
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• v.4
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• pp.55-60
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• 1984

Silicastone of Hongcheon in Kangweon province was characterized by means of chemical analysis, scanning electron microscope, polarization microscope and x-ray diffractometer. The results showed that the purity of $SiO_2$ is over 97.64 in Wt-%. It also contains 0.046-0.417 Wt-% $Fe_2O_3$ and some others as impurity. The impuity exist as a isolated mineral type of hematite, sericite, apatite etc.

• Proceedings of the Korea Concrete Institute Conference
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• 1989.10a
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• pp.1-4
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• 1989

Recently, as the natural aggregates are exhausted, using the crashed stones bring the possibility of the alkali-aggregate reactivity. In this study, the samples are collected from the stony moutains chosen by using a geoligical survey map and analyzed in terms of the amount and the shape of the reaction minerals by a polarization microscope and X-ray diffraction which beling to the petrographic examination of aggregates for concrete. From this study, most samples of the sedimentary rocks and the granitte of the ignious rocks show the possibility of the alkali-aggregate reactivity.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.212-221
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• 2001

This paper introduces the characteristics and generation of the synchrotron radiation (SR). SR has the very high spectral brilliance, broad spectral range, X-ray wavelength tunability, high degree of polarization and collimation, and pulsed time structure. Also describes the technologies to apply in the fields of geology and environmental sciences. These include X-ray tomography, XRF, EXAFS, XANES, DAC, IVP experiments. Further, nuclear power generation and nuclear waste disposal methods are mentioned relating to energy. Using these, analyses of the chemistry, crystal structure and chemical combining states of minerals and rocks can be carried out. Applications in the fields of the economic geology, paleontology and environmental sciences are open too. Informations of the Earth interior materials' behavior under high pressure-temperature can be acquired.

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.897-907
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• 1997

Thin films of Bi4-xSmxTi3O12(0$\leq$x$\leq$2) were prepared on Pt/Ti/SiO2/Si(100) at $700^{\circ}C$ using spin-coating with sols derived from Bi-Sm-Ti complex alkoxides. From X-ray diffraction analysis, it was observed that Sm-substituted phases resembled ferroelectric Bi4Ti3O12 in structure. Variations of their lattice parameters depending on the amount of Sm-substitution showed that an anomalous structural distortion might exist at x=1. The grain sizes of the thin films decreased from 0.115 ${\mu}{\textrm}{m}$ to 0.078${\mu}{\textrm}{m}$ with increasing the amount of Sm-substitution. The dielectric constants and the remanent polarizations of the thin films decreased with increasing the amount of the Sm-substitution, which were related to decrease of the stereo-active Bi3+ ion contributing to polarization. However, these values were exceptionally high at x=1, compared to those of the other substituted phases. Such an anomaly suggests that the phase of x=1 has 1:1 chemical ordering between Sm and Bi in structure. The thin films of all compositions except x=2 showed ferroelectricity. The thin film of x=2 was paraelectric, whose grains were too fine to exhibit ferroelectricity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.264-267
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• 2004

[ $Bi_{3.25}La_{0.75}Ti_3O_{12}$ ] (BLT) thin films were prepared by using metal organic decomposition method onto the $LaNiO_3$ (LNO) bottom electrode. Both the structure and morphology of the films were analyzed by x-ray diffraction (XRD) and atomic force microscope (AFM). Even at low temperatures ranging from 450 to $650^{\circ}C$, the BLT thinfilms were successfully deposited on LNO bottom electrode and exhibited (117) orientation. The BLT thin films annealed as low as $600^{\circ}C$ showed excellent ferroelectricity, higher remanent polarization and no significant degradation of switching charge at least up to $5{\times}10^9$ switching cycles at a frequency of 100 kHz and 5 V. For the annealing temperature of $600^{\circ}C$, the remanent polarization Pr and coercive field were $23.5\;C/cm^2$ and 120 kV/cm, respectively.

• Corrosion Science and Technology
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• v.5 no.1
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• pp.15-22
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• 2006

The introduction of two-grid inside a conventional process system produces a reactive coating deposition and increases metal ion ratio in the plasma, resulting in denser and smoother films. The corrosion behaviors of TiN coatings were investigated by electrochemical methods, such as potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in deaerated 3.5% NaCl solution. Electrochemical tests were used to evaluate the effect of microstructure on the corrosion behavior of TiN coatings exposed to a corrosive environment. The crystal structure of the coatings was examined by X-ray diffractometry (XRD) and the microstructure of the coatings was investigated by scanning electron microscopy (SEM) and transmission electron spectroscopy (TEM). In the potentiodynamic polarization test and EIS measurement, the corrosion current density of TiN deposited by two grid-attached magnetron sputtering was lower than TiN deposited by conventional magnetron type and also presented higher Rct values during 240 h immersion time. It is attributed to the formation of a dense microstructure, which promotes the compactness of coatings and yields lower porosity.

• Journal of Ocean Engineering and Technology
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• v.17 no.3 s.52
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• pp.39-45
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• 2003

Shot peening is an effective method of improving the fatigue strength of components and structures. The compressive residual stress produced by surface plastic deformation with shot peening is usually regarded as the major factor in increasing fatigue strength. In this study, the influence of shot peening on corrosion was investigated. Spring steel immersed in $3.5\%$ NaCl prior was used to evaluate the effect of shot peening on fatigue properties. The immersion test was performed on the five kinds of specimens with shot peened and unpeened. The distributions of residual stresses of shot peened spring steels were measured in an X-ray diffraction apparatus, using the two-point method. Corrosion potential, polarization curve, residual stress, etc. were investigated, based on the experimental results. From test results, the effect of shot peening on the corrosion was evaluated.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.758-763
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• 2006

Perovskites with nominal compositions $Ln_{0.8}Sr_{0.2}CoO_{3-\delta}$ (Ln=Gd, Nd, Pr, Sm, or Yb) were fabricated as cathode materials using a solid-state reaction method for low-temperature operating Solid-Oxide Fuel Cells (SOFCs). X-ray diffraction analysis and microstructure observation for the sintered samples were performed. The ac complex impedance was measured in the temperature range of $600-900^{\circ}C$ in air and fitted with a Solartron ZView program. The crystal structure, microstructure, electrical conductivity, and polarization resistance of $Ln_{0.8}Sr_{0.2}CoO_{3-\delta}$ were characterized systematically.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.565-568
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• 2001

We have fabricated $Bi_{3.25}La_{0.75}Ti_{3}O_{12}(BLT)$ thin(200nm) films on the $Pt/Ti/SiO_{2}/Si$ substrates using a MOD(Metalorganic decomposition) method with annealing temperature from $550^{\circ}C$ to $750^{\circ}C$. The structural properties of the films examined by x-ray diffraction. The layered-perovskite phase obtained above $600^{\circ}C$. Scanning electron micrographs showed uniform surface composed of rodlike grains. The grain size increased with increasing annealing temperature. The BLT thin films showed little polarization fatigue test up to $3.5{\times}10^{9}$ bipolar cycling at a 5V and 100kHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.287-287
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• 2007

The ferroelectric and electric properties of UV-irradiated bismuth lanthanum titanate (BLT) films prepared using photosensitive starting precursors were characterized. The effects of lanthanum doping on ferroelectric and electric properties were investigated by polarization-electric field hysteresis loops and leakage current-voltage measurements. X-ray diffractometer and ellipsometry were served to provide the information about the crystalline structure and thickness of the films after annealing. The images of the surface microstructure and direct-patterned BLT films were observed by using scanning electron microscopy. The effects of lanthanum doping on the electric properties of direct-pattern able BLT films and their direct-patterning were studied.