• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.219-222
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• 1997

The principle of dark field imaging is comprehensively discussed using real images of dislocations, stacking faults and gettering phenomena due to defects obtained by Cz Si wafers and LEC semi-insulating GaAs crystals. Resulution of dark field imaging is improved by Fourier transformation of Fraunhofer diffraction pattern obtained at an out-of focusing position of an objective lens.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.126-130
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• 1990

A single-layer Perceptron with 4x4 input neurons and one output neuron is optically implemented. Holo-graphic lenslet arrays are usee for the programmable optical interconnection topology. The hologram is bleached in order to increase the diffraction efficiency. It is shown that the performance of Perceptron depends on the learning rate, the inertia rate, and the correlation of input patterns.

• Journal of Biomedical Engineering Research
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• v.11 no.1
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• pp.19-24
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• 1990

A simple diffraction grating spectrometer is successfully utilized to distinguish the similar red colored sediments obstained from both of cancer and non-cancer urine reactions caused by the the previous developed reagent for the cancer diagnosis by examining their spectral absorption bands in order to improve its sensitivity and specficity. It is found that the cancer and non-cancer absorp- tion band regions lie between 4250 A and 4750 A and between 5250 A and 5400 A, respectively.

• Journal of the Korean Ceramic Society
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• v.15 no.1
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• pp.21-27
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• 1978

Hadong Kaolin (Halloysite) was granulated cylindrically and treated with 1N aqueous sodium hydroxide solution for 6-48 hrs at 60-10$0^{\circ}C$. The crystalling structure of surface of the products was studied by X-ray powder diffraction method. The reaction rate of halloysite to sodium A zeolite showed a gradual decrease from surface to inner layer. At the surface layer, the reaction mechanism was observed as first order consecutive reaction as follows: halloysitelongrightarrowamorphous aluminosilicatelongrightarrowsodium A zeolitelongrightarrowhydroxysodalite By applying the above reaction mechanism, the rate constants and activation energies was measured.

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.341-346
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• 1989

In order to evaluate the oxidation behavior of $\beta$-Sialon, $\beta$-Sialon ceramics was prepared from Si3N4, Al2O3, AlN and Y2O3 system. The specimens were oxidized in an oxygen atmosphere at 1, 20$0^{\circ}C$ for 9days. Oxidation behavior was evaluated by weight gain oxidation process, surface roughness. Microscopy, EDX and X-ray diffraction analysis were also used for the evaluation. The weight and surface roughness ofoxidized specimens were increased with increasing the oxidation time. Oxidized products were mullite, $\alpha$-cristobalite, yttrium aluminum oxide and yttrium silicate oxide.

• Journal of Ocean Engineering and Technology
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• v.18 no.6 s.61
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• pp.29-36
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• 2004

Floating breakwaters have been recently studied to reduce the transmission ratio of wave energy. The numerical study shows how wave pressure and stress act on the rectangular floating breakwater under various regular wave conditions. In order to evaluate hydrodynamic pressure on the floating breakwater, the infinite element is applied to the linear wave diffraction and radiation problems. SAP2000, a structural analysis program, is used to evaluate stress on the floating breakwater.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3298-3300
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• 1999

In this paper, a $10{\times}10$ micro SLM array for phase and amplitude modulation of incident light is designed and fabricated using surface micromachining technology. Hidden spring structure is used in order to maximize the fill-factor and minimize diffraction effect at the support posts. Static and dynamic characteristics of designed micro SLM are simulated with ABAQUS and measured with optical measurement system using He-Ne laser and PSD(position sensitive devise).

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.344-347
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• 1985

Hew dual integral equation for electromagnetic field scattered by an arbitrary dielectric wedge is formulated. In order to check the validity and physical meaning of the formulated equation, it is applied to the well-known case which is the diffraction by a perfectly conducting wedge.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1032-1036
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• 1998

Intercalation compounds of organic anions into layered double hydroxides (LDH) are synthesized by the coprecipitation route. X-ray diffraction data reveal that the intercalated terephthalate (TP), naphthalene-2,6-disulfonate (NA26), and anthraquinone-2,6-disulfonate (AQ26) are arranged with their molecular planes perpendicular to the hydroxide layer. HPLC data show that 26.2% of TP and 73.8% of AQ26 are cointercalated, whereas NA26 is not intercalated into the Zn/Al-LDH. These results indicate the possibility of a molecular recognition ability of Zn/Al-LDH. The molecular recognition ability of intercalation into Zn/Al-LDH is in the order AQ26 > TP >> NA26.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.619-633
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• 1994

A wave deformation model for general purpose combined refraction, diffraction, and breaking is developed in the shallow water. A parabolic approximation equation considered a higher order diffraction term is derived from the previous mild slope equation. A wave energy dissipation term due to bottom friction and breaking is introduced from the turbulence model. The Crank-Nicoloson implicit scheme is used in the numerical calculation, then the solutions are compared with the various hydraulic experiment data in the circular, the elliptic shoal, and the surf zone. The wave height decay in the surf zone is sensitively affected by the incident wave steepness, and the wave height variation around the elliptic shoal is well explained by the non-linear dispersion relation and the wave energy dissipation term. The model is also applied to a field coastal area and reasonable results are obtained.