• Korean Journal of Materials Research
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• v.33 no.2
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• pp.54-62
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• 2023

The most comprehensive and particularly reliable method for non-destructively measuring the residual stress of the surface layer of metals is the sin²ψ method. When X-rays were used the relationship of ε_φψ-sin²ψ measured on the surface layer of the processing metal did not show linearity when the sin²ψ method was used. In this case, since the effective penetration depth changes according to the changing direction of the incident X-ray, σ_φ becomes a sin²ψ function. Since σ_φ cannot be used as a constant, the relationship in ε_φψ-sin²ψ cannot be linear. Therefore, in this paper, the orthogonal function method according to Warren's diffraction theory and the basic profile of normal distribution were synthesized, and the X-ray diffraction profile was calculated and reviewed when there was a linear strain (stress) gradient on the surface. When there is a strain gradient, the X-ray diffraction profile becomes asymmetric, and as a result, the peak position, the position of half-maximum, and the centroid position show different values. The difference between the peak position and the centroid position appeared more clearly as the strain (stress) gradient became larger, and the basic profile width was smaller. The weighted average strain enables stress analysis when there is a strain (stress) gradient, based on the strain value corresponding to the centroid position of the diffracted X-rays. At the 1/5 I_max max height of X-ray diffraction, the position where the diffracted X-ray is divided into two by drawing a straight line parallel to the background, corresponds approximately to the centroid position.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.400-403
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• 2002

The fundamental experiments for measuring soft x-ray characteristics from the vacuum capillary are described. These experiments were primarily performed in order to generate line spectra such as x-ray lasers. The generator consists of a high-voltage power supply, a polarity-inversion ignitron pulse generator, a turbo-molecular pump, and a radiation tube with a capillary. A high-voltage condenser of 200 nF in the pulse generator is charged up to 20 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing the ignitron. During the discharge, weakly ionized plasma forms on the inner and outer sides of a capillary. In the present work, the pump evacuates air from the tube with a pressure of about 1 mPa, and a demountable capillary was developed in order to measure x-ray spectra according to changes in the capillary length. In this capillary, the anode (target) and cathode elements can be changed corresponding to the objectives. The capillary diameter is 2.0 mm, and the length is adjusted from 1 to 50 mm. When a capillary with aluminum anode and cathode electrodes was employed, both the cathode voltage and the discharge current almost displayed damped oscillations. The peak values of the voltage and current increased when the charging voltage was increased, and their maximum values were -10.8 kV and 4.7 kA, respectively. The x-ray durations observed by a 1.6 ${\mu}$m aluminum filter were less than 30 ${\mu}$s, and we detected the aluminum characteristic x-ray intensity using a 6.8 ${\mu}$m aluminum filter. In the spectrum measurement, two sets of aluminum and titanium electrodes were employed, and we observed multi-line spectra. The line photon energies seldom varied according to changes in the condenser charging voltage and to changes in the electrode element. In the case where the titanium electrode was employed, the line number decreased with corresponding decreases in the capillary length. Compared with incoherent visible light, these rays from the capillary were diffracted and diffused greatly after passing through two slits.

• The Journal of Korean Medicine
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• v.23 no.2
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• pp.88-96
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• 2002

Objective : This study attempted to evaluate the ultrasonographic diagnosis of sinusitis compared to X-ray diagnosis and further to help the diagnosis and treatment of sinusitis through oriental medicine. Methods : Both A-mode ultrasonography and X-ray were taken of 30 symptom-positive patients and 10 symptom-negative controls. Nasal obstruction, rhinorrhea, postnasal drip, headache (facial pain), hyposmia (anosmia), throat discomfort and chronic cough were included in the symptoms of sinusitis. Both ultrasonographic and X-ray findings were divided into four groups (clear, mucosal thickening, air-fluid level and cystic shape) according to severity. Results : 1. The symptoms of patients (n=30) were as follows: nasal obstruction (83.3%), rhinorrhea (70.0%), postnasal drip (60.0%), chronic cough (53.3%), headache (40.0%), throat discomfort (40.0%), hyposmia (26.7%). 2. There was a significant correlation between symptoms and ultrasonographic findings (n=40, ${\gamma}=0.550$, P=0.001). 3. There was a significant correlation between symptoms and X-ray findings (n=40, ${\gamma}=0.555$, P=0.001). 4. There was a significant whole coincidence between ultrasonographic and X-ray findings (n=60, ${\gamma}=0.335, P=0.00l). Moreover, there was a significant coincidental trend between the two findings as they became severe (n=60, ${\gamma}=6.284$, P=0.012). 5. The distance of the ultrasonographic echoes was as follows: clear echo (n=9, from transducer pulse to air mucosa echo) $0.90{\pm}0.19cm$, mucosal thickening echo (n=23, from transducer pulse to air mucosa echo) 1.85{\pm}0.14cm, air-fluid level echo (n=26, from transducer pulse to back wall echo) $3.70{\pm}0.16cm$. 6. The highest diagnostic reliability of the ultrasonographic findings compared to X-ray findings was as follows: over-diagnosis in clear finding 77.3%, matched diagnosis in mucosal thickening finding 62.0%, matched diagnosis in air-fluid level finding 86.7%, matched diagnosis and under-diagnosis in cystic shape finding 50.0%. 7. In mucosal thickening, air-fluid level and cystic shape finding, there was a significant individual coincidence between the ultrasonographic and X-ray findings. In clear finding, there was no significant individual coincidence between the two findings. Conclusion : The ultrasonographic diagnosis significantly reflects the symptoms of sinusitis like X-ray diagnosis and is a valuable tool to screen prognostic factors such as mucosal thickening, air-fluid level and cyst. Therefore the ultrasonography will be useful for the diagnosis and treatment of sinusitis in oriental medicine.

• Korean Journal of Environmental Biology
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• v.18 no.4
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• pp.387-394
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• 2000

The morphological characteristics between male and female of three species, Chaenogobius urotaenia, C. sp. MR, C. sp. BW, collected from June 1996 to Aug. 1999, Korea was studied. Of 13 characters to be studied, 12 characters with exception of caudal fin ray length were significantly different among three species and these three species were distinguished each other by the results of the multiple comparison test (REGWQ test). Interspecific differences in female was distinct in body depth, head length, caudal peduncle length, caudal peduncle depth, snout length, pectoral fin ray length; In particular, C. sp. MR was shorter in upper jaw length, anal fin ray length and eye diameter, and to be smaller in head depth and head width than other two species. Chaenogobius urotaenia was longer in pelvic fin ray length. In case of male, there was not characters to distinguish each one among three species; Chaenogobius urotaenia was longer in head length, eye diameter and pelvic fin ray length than other two species, C. sp. MR to be longer in caudal peduncle length, but shorter in snout length and anal fin ray length, and to be lower in head depth. C. sp. BW was higher in body depth and caudal peduncle depth, and to be longer in upper jaw length and pectoral fin ray length. Both of male and female among three species didn't have any difference in caudal fin ray length. [Chaeogobius urotaenia, C. sp. MR, C. sp. BW, morphological characteristics].

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.261.1-261.1
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• 2008

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.122.2-122
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• 1999

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.455-460
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• 2004

There have been many speculations about the presence of cosmic ray protons (CRps) in galaxy clusters over the past two decades. However, no direct evidence such as the characteristic $\gamma$-ray signature of decaying pions has been found so far. These pions would be a direct tracer of hadronic CRp interactions with the ambient thermal gas also yielding observable synchrotron and inverse Compton emission by additionally produced secondary electrons. The obvious question concerns the type of galaxy clusters most likely to yield a signal: Particularly suited sites should be cluster cooling cores due to their high gas and magnetic energy densities. We studied a nearby sample of clusters evincing cooling cores in order to place stringent limits on the cluster CRp population by using non-detections of EGRET. In this context, we examined the possibility of a hadronic origin of Coma-sized radio halos as well as radio mini-halos. Especially for mini-halos, strong clues are provided by the very plausible small amount of required CRp energy density and a matching radio profile. Introducing the hadronic minimum energy criterion, we show that the energetically favored CRp energy density is constrained to $2\%{\pm}1\%$ of the thermal energy density in Perseus. We also studied the CRp population within the cooling core region of Virgo using the TeV $\gamma$-ray detection of M 87 by HEGRA. Both the expected radial $\gamma$-ray profile and the required amount of CRp support this hadronic scenario.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.575-578
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• 2004

High resolution observations of cluster of galaxies by Chandra have revealed the existence of an X-ray emitting comet-like galaxy C153 in the core of cluster of galaxies A2125. The galaxy C153 moving fast in the cluster core has a distinct X-ray tail on one side, obviously due to ram pressure stripping, since the galaxy C153 crossed the central region of A2125. The X-ray emitting plasma in the tail is substantially cooler than the ambient plasma. We present results of two-dimensional magnetohydrodynamic simulations of the time evolution of a sub clump like C153 moving in magnetized intergalactic matter. Anisotropic heat conduction is included. We found that the magnetic fields are essential for the existence of the cool X-ray tail, because in non-magnetized plasma the cooler sub clump tail is heated up by isotropic heat conduction from the hot ambient plasma and does not form such a comet-like tail.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.51-54
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• 2002

Recently, due to its better photosensitivity in X-ray, the amorphous selenium based photoreceptor is used on digital direct method conversion material. Compared to other photoconductive material, amorphous selenium has good X-ray response characteristic and low leakage current. It has many parameters of detecting X-ray response on selenium. Among of them, it is well known that manufacture of a-Se is the most basic element. In this paper, we fabricated two types of amorphous selenium sample which had time variable. The one was fabricated continuous deposition sample and the other was step by step sample. Thickness of sample was $300{\mu}m$ and top electrode was evaporated gold. We investigated the leakage current and photo current of them and analysed their electrical characteristics. For analyzing morphology of samples, SEM and surface was pictured. We found that step by step deposition method could be applied for novel fabricating amorphous selenium film.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.353-362
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• 1999

This paper presents a shape reconstruction method for automatic inspection of the solder joints on PCBs using X-ray. Shape reconstruction from X-ray radiographic image has been very important since X-ray equipment was used for improving the reliability of inspection result. For this purpose there have been lots of previous works using tomography, which reconstructs the correct shape, laminography or tomosynthesis, which are very fast algorithm. Latter two methods show outstanding performance in cross-sectional image reconstruction of lead type component, but they are also known to show some fatal limitations to some kinds of components such as BGA, because of shadow effect. Although conventional tomography does not have any shadow effect, the shape of PCB prohibits it from being applied to shape reconstruction of solder joints on PCB. This paper shows that tomography using Iterative Reconstruction Technique(IRT) can be applied to this difficult problem without any limitations. This makes conventional radiographic instrument used for shape reconstruction without shadow effect. This means that the new method makes cost down and shadow-free shape reconstruction. To verify the effectiveness of IRT, we develop three dimensional model of BGA solder ball, make projection model to obtain X-ray projection data. and perform a simulation study of shape reconstruction. To compare the performance of IRT with that of conventional laminography or tomosynthesis, reconstruction data are reorganized and error analysis between the original model are also performed.