• Journal of radiological science and technology
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• v.38 no.1
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• pp.39-49
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• 2015

One of properties which X-ray and Neutron can be applied nondestructive test is penetration into the object with interaction leads to decrease in intensity. X-ray interaction with the matter caused by electrons, Neutron caused by atoms. They share applications in nondestructive test area because of their similarities of interaction mechanism. Grating interferometer is the one of applications produces phase contrast image and dark field image. It is defined by Talbot interferometer and Talbot-Lau interferometer according to Talbot effect and Talbot-Lau effect respectively. Talbot interferometer works with coherence beam like X-ray, and Talbot-Lau has an effect with incoherence beam like Neutron. It is important to expect the interference in grating interferometer compared normal nondestructive system. In this paper, simulation works are conducted according to Talbot and Talbot-Lau interferometer in case of X-ray and Neutron. Variation of interference intensity with X-ray and Neutron based on wave theory is constructed and calculate elements consist the system. Additionally, Talbot and Talbot-Lau interferometer is simulated in different kinds of conditions.

• Korean Journal of Optics and Photonics
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• v.12 no.2
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• pp.83-90
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• 2001

The Talbot effect for periodic objects with the spatial period p illuminated by expanded coherent light is analyzed by Fresnel diffraction theory, and the Talbot distance (Zr) at which we can observe 1: 1 imaging without any lenses can be defined. We confmned experimentally the Talbot imaging of line, circular, X -type and '||'&'||'copy;-type 2 dimensional alTay gratings at ZT. At the same time, we observed phase reversed Talbot imaging at Zr/2 and Talbot subimage with p/2 at Zr/4 and 3Zr/4. The visibility of Talbot images as a function of the number of slits of the input grating was measured by the FFf (Fast Fourier Transform) results of these images. As a result stationary maximum visibility of V = 0.25 was obtained from grating numbers with more than 15 slit pairs.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.10a
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• pp.145-150
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• 1998

• Structural Engineering and Mechanics
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• v.73 no.3
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• pp.287-302
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• 2020

This investigation deals with a size-dependent coupled thermoelasticity analysis based on Green-Naghdi (GN) theory in nano scale using a new modified nonlocal model of heat conduction, which is based on the GN theory and nonlocal Eringen theory of elasticity. In the analysis based on the proposed model, the nonlocality is taken into account in both heat conduction and elasticity. The governing equations including the equations of motion and the energy balance equation are derived using the proposed model in a nano beam resonator. An analytical solution is proposed for the problem using the Laplace transform technique and Talbot technique for inversion to time domain. It is assumed that the nano beam is subjected to sinusoidal thermal shock loading, which is applied on the one of beam ends. The transient behaviors of fields' quantities such as lateral deflection and temperature are studied in detail. Also, the effects of small scale parameter on the dynamic behaviors of lateral deflection and temperature are obtained and assessed for the problem. The proposed GN-based model, analytical solution and data are verified and also compared with reported data obtained from GN coupled thermoelasticity analysis without considering the nonlocality in heat conduction in a nano beam.

• Structural Engineering and Mechanics
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• v.60 no.3
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• pp.529-545
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• 2016

In this article, the generalized coupled non-Fickian diffusion-thermoelasticity analysis is carried out using an analytical method. The transient behaviors of field variables, including mass concentration, temperature and displacement are studied in a strip, which is subjected to shock loading. The governing equations are derived using generalized coupled non-Fickian diffusion-thermoelasticity theory, which is based on Lord-Shulman theory of coupled thermoelasticity. The governing equations are transferred to the frequency domain using Laplace transform technique and then the field variables are obtained in analytical forms using the presented method. The field variables are eventually determined in time domain by employing the Talbot technique. The dynamic behaviors of mass concentration, temperature and displacement are studied in details. It is concluded that the presented analytical method has a high capability for simulating the wave propagation with finite speed in mass concentration field as well as for tracking thermoelastic waves. Furthermore, the obtained results are more realistic than that of others.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.606-612
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• 2003

The self-imaging effect or lensless imaging effect of a phase line grating is theoretically analyzed by using Fresnel diffraction theory, then experimentally investigated. The self-imaging distance $z_{T,p}$, that is the imaging distance being perfectly copied from the phase distribution of the phase grating to its intensity distribution with the magnification of 1X, can be uniquely defined as the (4n-3) $z_{T,a}$/4(n=positive integers), where rte is the well-known self-imaging distance of an amplitude grating. When the coherent laser beam is illuminated at the phase grating, the self-imaged images were obtained at $z_{T,p}$= $z_{T,a}$/4 and $z_{T,p}$=5 $z_{T,a}$/4 without any optics. On the other side, the phase-reversed self-imaging was obviously observed at $z_{T,p}$ = 3 $z_{T,a}$/4. The visibility of self-imaged images of a phase line grating as a function of the number of slits of the input grating was measured by the FFT(Fast Fourier Transform) results of the self-imaging images. As a result a stationary maximum visibility of V = 0.10 can be obtained from a grating with more than 15 slit pairs.n 15 slit pairs.