• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.354-357
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• 1995

Measurements of X-ray diffuse scatterings were made in disordered single crystal of Fe-28.3 at%Pt Invar alloy around a 200-Bragg peak in a wide temperature range between 15 K and 300 K. Observed diffuse scatterings were almost spherical, suggesting a homogeneous disordered alloy. However, the qdependence of the observed thermal diffuse scattering was different from the usual type, indicating a possibility of existence of local distortion of lattice accompanied by a large gradient of stress.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.591-602
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• 2009

The Compton backscatter technique has been applied to lap-joint in aircraft structure in order to determine mass loss due to exfoliative corrosion of the aluminum alloy sheet skin. The mass loss of each layer has been estimated from Compton backscatter A-scan including the aluminum sheet, the corrosion layer, and the sealant. A Compton backscattering imaging system has been also developed to obtain a cross-sectional profile of corroded lap-splices of aging aircraft using a specially designed slit-type camera. The camera is to focus on a small scattering volume inside the material from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the layered structure is scanned by moving the scattering volume through the thickness direction of the specimen. The theoretical model of the Compton scattering based on Boltzmann transport theory is presented for quantitative characterization of exfoliative corrosion through deconvolution procedure using a nonlinear least-square error minimization method. It produces practical information such as location and width of planar corrosion in layered structures of aircraft, which generally cannot be detected by conventional NDE techniques such as the ultrasonic method.

• Journal of Mechanical Science and Technology
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• v.15 no.4
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• pp.441-447
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• 2001

Ultrasonic wave generation and propagation were modeled to simulate an ultrasonic test. A ray model was used for the modeling. Actual sound pressure distribution of the incident wave from an angle probe was analyzed using an ultrasonic visualization method to incorporate the actual sound pressure distribution in the model. In this method, the sound pressure was expressed by the density of rays and the reflection coefficient of ultrasonic beams. Reflection and mode conversion of rays were computed by the Snells law. Simulation programs for the problem of ultrasonic testing of a butt joint are built using this ray modeling. Simulation results for ultrasonic wave scattering from a defect and A-scan display in ultrasonic testing agreed with the actual experiment results.

• Journal of Environmental Science International
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• v.18 no.8
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• pp.911-918
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• 2009

Electromagnetic interference (EMI) is defined as the interaction phenomena of electromagnetic waves scattered from a large structure or complex terrain. In this study, the propagation of linear wave is modeled with ray theory, direct simulation Monte Carlo (DSMC), and some classical theories on flat plates. The wave physics of reflection, refraction, and diffraction are simulated for the investigation of front and back scattering of the one-dimensional plane wave from a tower with ray theory and DSMC, respectively. The effect of rotating disk idealized from the real wind-turbine blades is modeled with a simplified version of the classical electromagnetic theory as well as DSMC based on the ray theory.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.600-603
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• 2003

Energy spectrum modulation of X-ray source in digital mammography has been studied. In this study, we calculated various filtered spectra using the scattering data. Primary spectra were generated by Molybdenum (Mo) and Tungsten (W) targets. The materials of added filters are Molybdenum and Rhodium (Rh) for 40 kVp Mo. primary spectrum, the amounts of photons over whole energy ranges are attenuated to 0.43 with 0.03 mm Mo filter and 0.38 with 0.06 mm Mo filter while the photons of energy ranged from 17 keV to 20 keV. The photons of low energy ranged below 17 keV are considerably attenuated. This effect brings out reducing the scattered radiation and dose to the patient, and enhancing subject contrast in the image. The results show that filtered spectra are not seriously affected by X-ray tube loadability. Because the energy range from 17 keV to 20 keV is directly transmitted although low and high energies are mainly filtered.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.192.2-192.2
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• 2013

Crystalline order and surface stability of 1,4,5,8,9,11-hexaazatriphenylene-hexanitrile (HATCN) thin films on organic surface were investigated using grazing incidence wide angle x-ray scattering and x-ray reflectivity measurements. In the initial growth regime (less than 20 nm), HATCN molecules were stacked to low crystalline order with substantial amorphous phase. Meanwhile, a thicker film with 50 nm thickness showed high crystalline order of hexagonal phase with three different orientational domains. The domain distribution was quantitatively obtained as a function of tilted angle. By an organic-inorganic interface formation of IZO/HATCN thin film from an indium zinc oxide (IZO) electrode deposition, the surface stability of HATCN film was investigated and the sharp interface was confirmed by the x-ray reflectivity measurement.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.501-508
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• 2015

There are various Intercondyloid fossa X-ray taking methods. The methods carried out in clinics are Holmblad method, Camp-Conventry method, and Beclere method. Taking image of Intercondyloid fossa is carried a lot as basic examination for diagnosis related to simple fracture and cruciate ligament. Considering the condition and pains of patients, safe method is chosen but because Holmblad method can cause pains to knee part adhering to cassette, it is not easily used. In this study self-produced plane circular cone was attached to a cassette and in the posture for Holmblad method questionnaires of 100 applicants were analyzed to understand cognition on alleviation of pains, and the concentration of imge quality by scattering rays was measured with densitometer by taking human body phantom with X-ray. As a result, in the posture for Holmblad method, cognition on pains was alleviated by average 99%, and the change of concentration of X-ray film taken using phantom by scattering rays decreased statistically significantly compared to the cassette which did not use self-produced plane cone, therefor it is thought that the method can be valuably used in clinics.

• Journal of the Korean Society of Radiology
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• v.3 no.1
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• pp.5-9
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• 2009

The trend of Digital x-ray Detector research is to improve resolution of image and to embody large area imaging as well as dynamic moving imaging, etc. This research is divided with indirect conversion method and direct conversion method by radiation conversion process. Each conversion method has problems such as decrease of resolution from light scattering in indirect method case and not only low system stability but also difficult in dynamic moving imaging in direct method case. X-ray detector using liquid crystal has been researching to solve these problems, but it is difficulty in uniform injection of liquid crystal because of its structural properties. Therefore, this study suggests the structure which solves present problem. Also the possibility of suggested structure was investigated using simulation.

• Polymer Science and Technology
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• v.8 no.1
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• pp.57-66
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• 1997

• Proceedings of the Korean Vacuum Society Conference
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• 2005.02a
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• pp.100-100
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• 2005