• Applied Microscopy
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• v.32 no.3
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• pp.195-204
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• 2002

In this review, the fundamental concepts of delta function, convolution integral and Fourier transformation are discussed. The applications of Fourier transformation to slit function, two very narrow slits, two slits of appreciable width, periodic array of narrow slits, arbitary periodic function, diffraction gratings and gaussian functions are also introduced.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.2
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• pp.278-284
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• 1986

There are considerabel interests in the use of acoustical lengths for characterization of scattered data required in diffraction tomography. In this paper, we present two new methods, calculation of acoustical lengths by Hibert transform and estimate on of integrated values on the scan lines from calcualted vales. These techniques offer insight into the acquisition of projection data in diffraction tomography. The validity of the proposed methods has bee confirmed by computer simulation.

• Journal of the Optical Society of Korea
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• v.1 no.1
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• pp.36-40
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• 1997

Bragg diffraction of a strong reference beam from a steady-state photorefractive grating is measured experimentally and an analytic prediction is derived from the coupled wave equations of two-beam energy coupling. The relation between Bragg diffraction and two-beam coupling is used to check the mechanism of photorefractive grating formation.

• YAKHAK HOEJI
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• v.8 no.2
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• pp.37-44
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• 1964

The relationships involving acid-consuming capacity and X-ray powder diffraction patterns of aluminum hydroxide gel were studied. The aging of antacid efficacy of aluminum hydroxide gel has also been characterized by using X-ray powder diffraction. The acid-consuming capacity decreased with progress of crystallization from amorphous alumino gel, and it was found that aged product at 80.deg. C had crystal structure of bohmite (.alpha.-Al.sub 2/O$_{2}$(OH)$_{2}$). It was also noted that the rate of aging decreased with decreasing pH of aluminum hydroxide gel.

• Korean Journal of Crystallography
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• v.1 no.2
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• pp.91-98
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• 1990

A twin model for icosahedral phase of rapidly solidified AB transition metal alloy is suggested. Electron diffraction patterns of our icosahedral twin model are simulated, taking into account of multiple diffraction. The simulated pattern with 5-fold symmetry well agrees with the experimental one. Our twin model is closely relevant to the icosahedral phase.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.3
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• pp.22-27
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• 2004

Waveheight attenuation efficiencies of floating breakwaters in water of finite depth for a VLFS are studied numerically in accordance with the two body radiation-diffraction problem. Four different forms of the breaker are tested with a solid VLFS. The radiation-diffraction wave elevations between the breakwater and the VLFS are predicted directly instead of the far-field transmission-reflection coefficients of the breakwater.

• Journal of the Korean Ceramic Society
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• v.36 no.10
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• pp.1075-1079
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• 1999

LaSrCoO3 thin films were spin-coated onto the SrTiO3(100) substrates by the chemical solution process. X-ray diffraction $\theta$-2$\theta$ scans and X-ray diffraction $\beta$ scans were used to determine the crystallinity and in -plane alignment behavior of the films. The X-ray diffraction pattern showed the film obtained by annealing at 80$0^{\circ}C$ was highly oriented. The X-ray diffraction pole-figure analysis and reciprocal-space mapping (2$\theta$-$\Delta$$\omega$ scans) of the resulting film showed that the film comprising the pseduocubic phase had an epitaxial relationship with the SriO3 substrate.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.45-60
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• 2008

Here we consider the evaluation of the the dynamic component of the second order force due to wave diffraction by a circular cylinder analytically and numerically. The cylinder is fixed, vertical, surface piercing in water of finite uniform depth. The formulation of the wave-structure interaction is based on the assumption of a homogeneous, ideal, incompressible, and inviscid fluid. The nonlinearity in the wave-structure interaction problem arises from the free surface boundary conditions, namely, dynamic and kinematic free surface boundary conditions. We expand the velocity potential and free surface elevation functions in terms of a small parameter and then consider the second order diffraction problem. After deriving the pressure using Bernoulli's equation, we obtain the analytical expression for the dynamic component of the second order force on the cylinder by integrating the pressure over the wetted surface. The computation of the dynamic force component requires only the first order velocity potential. Numerical results for the dynamic force component are presented.

• Tribology and Lubricants
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• v.18 no.3
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• pp.187-193
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• 2002

The half-value breadth off-ray diffraction profile line is generally used for a factor in nondestructive hardness measuring method of steel. In this paper, the problem in using the half-value breadth for the hardness measuring method is evaluated in strain hardened steel. And new hardness measuring method using residual stress is proposed X-ray diffraction test after rolling contact fatigue test of ball bearing with inner race of various hardness are carried out to measure the distribution of residual stress and half-value breadth from surface. The result of this study shows that there is little correlation between half-value breadth and hardness in the higher strength region and in the region increasing the hardness by strain hardening. But the magnitude of residual stress on/under race after rolling contact fatigue test becomes clearly to be correlative with hardness. Thus, it is concluded that the hardness of strain hardened steel can be estimated by this relationship between residual stress and hardness.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.11a
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• pp.11-12
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• 2000

Non-stoichiometric ceramics of $Ni_{x}ZnO_{1-x}Fe_{2}O_{4}$ were prepared by self-propagating high temperature synthesis reaction with various processing conditions and their stoichometric numbers were determined by neutron diffraction. The neutron diffraction patterns were measured at room temperature using monochromatic neutrons with a wave length of 0.18339 nm from a Ge(331) mocochromator at a 90 degree take off angle. The Rietveld refinement of each pattern converged to good agreement (x2=1.88-2.24). The neutron diffraction analysis revealed the final stoichiometries of the ferrites were $Ni_{0.38}Zn_{0.62}Fe_{2}O_{4}$ and $Ni_{0.33}Zn_{0.67}Fe_{2}O_{4]$, respectively. This supports that final stoichiometric number of the self-propagating high temperature synthesis product can be controlled by the processing parameters during the combustion reaction.