• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.1035-1041
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• 2016

Internal cracks in products are invisible and can lead to fatal crashes or damage. Since X-rays can penetrate materials and be attenuated according to the material’s thickness and density, they have rapidly become the accepted technology for non-destructive inspection of internal cracks. This paper presents a robust crack filter based on local gray level variation and multiscale analysis for automatic detection of cracks in X-ray images. The proposed filter takes advantage of the image gray level and its local variations to detect cracks in the X-ray image. To overcome the problems of image noise and the non-uniform intensity of the X-ray image, a new method of estimating the local gray level variation is proposed in this paper. In order to detect various sizes of crack, this paper proposes using different neighboring distances to construct an image pyramid for multiscale analysis. By use of local gray level variation and multiscale analysis, the proposed crack filter is able to detect cracks of various sizes in X-ray images while contending with the problems of noise and non-uniform intensity. Experimental results show that the proposed crack filter outperforms the Gaussian model based crack filter and the LBP model based method in terms of detection accuracy, false detection ratio and processing speed.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.107-114
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• 2023

X-ray fluorescence analysis has been widely used in the field of science and industry because it gives information about elements and their concentrations without destruction of samples. To increase analysis accuracy of fluorescence generated by photons of the transmission-type X-ray tube for mixture and compound samples would be recommend to have strong energy near 10 keV and 20 keV simultaneously. Tungsten of 9.65 keV and molybdenum of 17.48 keV were considered as targets with dual deposition structure for obtaining two strong characteristic X-rays, and the transmission-type X-ray tube was analyzed using Geant4 Monte Carlo simulation. The W-Mo structure resulted in strong characteristic X-ray near 10 keV and 20 keV simultaneously. A structure with Mo-W multilayers of 5 ㎛ thick also gave optimal spectrum. Various material combination and thickness optimization for the dual-structured target can give X-ray spectrum with strong characteristic X-ray of specific energies.

• Tribology and Lubricants
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• v.19 no.1
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• pp.1-8
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• 2003

Recently, PM-high speed steel(PM-HSS) has reportedly been a good alternative material for rolling mill because of its superior performance to conventional HSS. This paper has been aimed to investigate the possibility for application to rolling contact element for PM-HSS by X-ray diffraction technique. The X-ray elastic constant for PH-HSS has been found by X-ray diffraction during the four-point bending test. Residual stress and half-value breadth on the contact surface during rolling contact fatigue process by X-ray diffraction have also been measured. The result of this study shows that the application of X-ray diffraction technique to PM-HSS could be as possible alternative material as conventional HSS. Half-value breadth on rolling contact surface by X-ray diffraction is not changed during rolling contact fatigue process. On the other hand, the residual stress is changed. This suggests that dislocation reaction has been hardly occurred in rolling contact, depending on super-saturated carbon in PM-HSS.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.46.1-46.1
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• 2014

In understanding "cooling flow" problem and the galaxy-SMBH co-evolution, AGN feedback is considered as one of the most important phenomena. Among various AGN feedback phenomena, X-ray cavities are particularly useful for studying AGN feedback over 10 kpc scales, as the origin of X-ray cavities is believed to be related to radio jet from AGN. For a comprehensive study of X-ray cavities, we collect all available diffuse X-ray data of galaxies in various galaxy environments, ranging from field galaxies to galaxy clusters, using the Chandra X-ray data archive. As a result we build up a sample of 87 targets showing enough X-ray photons to perform the analysis. Using modeling and unsharp masking techniques, we detected X-ray cavities and measured their physical properties (i.e., cavity size) for the 49 targets. Here, we present X-ray cavity properties and discuss environmental effects.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.211-217
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• 2010

A micro-focus X-ray computed tomography (CT) was employed to determine quantitative phase analysis of skarn Zn-Pb-Cu ore by nondestructive visualization of the internal mineral distribution of a skarn ore. The micro CT images of the ore were calibrated to remove beam hardening artifacts, and compared with its scanning electron microscope (SEM) images to set the threshold of CT number range covering sulfide ore minerals. The volume ratio of sulfide and gangue minerals was calculated 20.5% and 79.5%, respectively. The quantitative 3D X-ray CT could be applied to analyse the distribution of economic minerals and their recovery.

• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.64-70
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• 1986

In this investigation x-ray diffraction method was mainly studied for quantitative analysis of clinker mineral composition. And also optical microscopic observation and Bogue calculation method were applied to compare with the x-ray diffraction method. In the procedure of x-ray diffraction analysis graphite monochromator automatic divergence slit and spinner for sample holder were used for minimizing the error due to the operation of the equipment. Especially the separation of overlapped peaks were proceeded by micro-processor automatically. The results of x-ray diffraction method for synthesized clinker were consistent with the Bogue value and the results of optical microscopic observation. However the results of quantitative analysis of mineral composition or commercial clinker containing solid solution of minor component were different from the Bogue value. On the other hand they agreed reasonably well with results of the optical mic-roscopic observation.

• 전기의세계
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• v.13 no.3
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• pp.13-20
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• 1964

The measurements of X-ray and Gamma-ray Dose Rate have been successfully made by measuring the short circuit current of the Silicon P-N Junction Diode being irradiated. The short circuit current flows when a silicon P-N Junction Diode is irradiated by X-ray of Gammaray radiations due to photovoltaic effect. A brief analysis is given in order to verify the proportionality of a short circuit current to the Dose Rate. Using this method, measurements of X-ray Dose Rate were carried out in the range of 0.05-1600 r/m successfully. The calibration was made by comparing with Victoreen condenser r-meter. Some advantages in this Dose Rate meter over a condenser r-meter were found. One can measure a continous variation of X-ray Dose Rate with this rate meter at the control console of X-ray device.

• Journal of the Korean Society of Industry Convergence
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• v.11 no.4
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• pp.195-199
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• 2008

The carbon fiber has low x-ray absorption property and high stiffness. This is the reason why many CT(Computed Tomography) manufacturer use carbon fiber in couch tabletop for CT scanner. In this paper, we design and make the couch tabletop made of carbon fiber composite, and verify the validity in CT scanner. In designing the couch tabletop, to determine the aluminum equivalent thickness of couch tabletop, we evaluate X-ray the transmissivity of aluminum and carbon plate in 80-120kVp X-ray energy range. And we perform structural analysis and mechanical design using determined thickness of carbon sheet. In conclusion, it was evaluated that manufactured couch tabletop satisfies X-ray transmissivity and mechanical requirements in CT scanner.

• Journal of Advanced Navigation Technology
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• v.11 no.2
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• pp.163-169
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• 2007

In this paper, we propose a method of trigger pulse generation to capture the image on time by making a synchronization between the x-ray generator and digital x-ray image acquisition system. we designed a wireless trigger pulse generation circuit to make a synchronization between x-ray generator and digital image acquisition system and analysis its performance. When it starts to detect a certain level of x-ray radiation or above from the air, this method starts to generate a ACQ_START signal to indicate the timing for image acquisition starting from digital image acquisition system. Hence, when it starts to detect under certain level of x-ray signal from the air, this method starts to generate a ACC_END signal to indicate the timing for image acquisition stop from digital image acquisition system. Image acquisition is activated only this time between ACQ_START and ACQ_END signal. By doing this wireless detecting of x-ray signal from remote, we can get more accurate timing for capturing the x-ray image and any type of x-ray generator can be connected to digital image acquisition system, regards of wired protocol. This makes easy installation. We could get 3.5 line pair / mm resolution at 20 mAs of x-ray level with resolution chart. This is same or better image comparing to conventional wired result.

• Progress in Medical Physics
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• v.14 no.3
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• pp.161-166
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• 2003

To evaluate the performance of cadmium sulfide as a multi-function X-ray dosimeter, we made an X-ray detector that was based on cadmium sulfide using evaporation technology, and measured its response to X-ray exposure. The voltages of cadmium sulfide were measured on the various X-ray tube potentials, X-ray tube currents and exposure times. The regression analysis of the voltage response of CdS on the tube-potential variation was y=0.0995x-0.1146 ($R^2$=0.9595, $\sigma$=0.08, standard error=2%) and the regression analysis of the voltage response of CdS on the tube-potential variation was y=0.0439x+1.1891 ($R^2$=0.9021, $\sigma$=0.04, standard error=1.8%) The regression analysis of the voltage response of CdS on the X-ray exposure time variation was y=8.2853+5.5878 ($R^2$=0.7287, $\sigma$=0.06, standard error=1.9%). In conclusion, cadmium sulfide responded linearly to the variation X-ray conditions, suggesting cadmium sulfide to be a feasible X-ray sensor of multi-function dosimeter related instruments.