• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.831-840
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• 2019

The X-ray detector by liquid crystal with front light was proposed and verified by a X-ray image. The proposed detector utilizes the visible light instead of the electric signal by transistor. Therefore, it shows low noise and can be fabricated at low cost. The liquid crystal detector uses the orientation change of the liquid crystal molecule by conductivity change of the photoconductive layer. We can get the X-ray image from the transmitted light through the liquid crystal. The X-ray dose was calibrated from the measured transmittance of the visible light after comparison to the reference transmittance curve of the liquid crystal. The amorphous Se was used for photo con ducting layer and parylene was used for the liquid crystal alignment instead of the conventional alignment layer which needs high-temperature process over 200℃. The proposed X-ray detector can decrease the X-ray dose by high sensitivity which was verified by simulation. After the fabrication of the X-ray detector, the X-ray image was obtained as a function of the bias voltage to the liquid crystal. 10 lines/mm resolution was obtained from the line pattern and we will apply it to the 17inch diagonal liquid crystal X-ray detector with 3π retardation.

• The Korean Journal of Food And Nutrition
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• v.28 no.1
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• pp.126-133
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• 2015

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch's thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. This result is appeared equally at wheat, corn and sweet potato starch. At this study, we treated potato, wheat, corn and sweet potato starch by ohmic/conventional method and observed change of external structure by microscope and internal structure by X-ray diffractometer. Conventional heated at $55^{\circ}C$ potato starch was not external structural changes. But ohmic heated potato starch is showed largely change. Some small size starch particle were broken or small particles are made of larger particle together or small particles caught up in the large particle. Changes in ohmic heated potato starch at $60^{\circ}C$ was greater. The inner matter came to an external particle burst inside and only the husk has been observed. The same change was observed in the rest of the starch. The change of internal structure of potato starch was measured using X-ray diffraction patterns. There was no significant difference between ohmic and conventional heating at $55^{\circ}C$. But almost every peak has disappeared ohmic at $60^{\circ}C$. Especially $5.4^{\circ}$ peak to represent the type B was completely gone. When viewed from the above results, external changes with change in the internal crystal structure of the starch particles were largely unknown to appear. In conclusion, during ohmic heating changes of starch due to the electric field with a change in temperature by the heating was found to have progressed at the same time.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.13-22
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• 2008

Internal voids affecting the mechanical properties of wood composite were classified into two catagories and characteristics of voids were examined according to density variation of strandboard. The void distribution and content of strandboard according to board density were measured by X-ray computed tomography system and analized using image processing software. Prior to investigation, the densities of strandboard were measured by densitometer and the results were showed high correlation with conventional oven drying method. Based on the image analysis conducted on captured images by X-ray tomography, low resolution can be used to capture the macro-voids (between strand) but not the micro-voids (within strands). Intermediate resolution can be used to capture both the macro and the micro-voids and high resolution can be successfully used to capture the majority of the micro-voids. The content of macro-void was measured and content of micro-void was computed by corresponding related equation. The macro-void distribution can be successfully understood and void content can be correctly estimated through the results.

• Progress in Medical Physics
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• v.28 no.3
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• pp.83-91
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• 2017

In this work, we investigated the recently proposed phase-contrast x-ray imaging (PCXI) technique, the so-called single grid-based PCXI, which has great simplicity and minimal requirements on the setup alignment. It allows for imaging of smaller features and variations in the examined sample than conventional attenuation-based x-ray imaging with lower x-ray dose. We performed a systematic simulation using a simulation platform developed by us to investigate the image characteristics. We also performed a preliminary PCXI experiment using an established a table-top setup to demonstrate the performance of the simulation platform. The system consists of an x-ray tube ($50kV_p$, 5 mAs), a focused-linear grid (200-lines/inch), and a flat-panel detector ($48-{\mu}m$ pixel size). According to our results, the simulated contrast of phase images was much enhanced, compared to that of the absorption images. The scattering length scale estimated for a given simulation condition was about 117 nm. It was very similar, at least qualitatively, to the experimental contrast, which demonstrates the performance of the simulation platform. We also found that the level of the phase gradient of oriented structures strongly depended on the orientation of the structure relative to that of linear grids.

• Resources Recycling
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• v.6 no.4
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• pp.11-16
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• 1997

The wastewater resulted from the process of developing and fuing for x-ray film manufachlring contains a lot of silvercomponent. The average concentation of silver-component is about 1,500 mgA. The wastewater contained silver-component is toxic when it is discharged to the natural ecosystem. So that we must to do pretreatment of wastewater prior to discharge. There are electrolysis. chemical precipitation, and metallic replacement as conventional lreabent proccss of fixer wastewater of x-ray film. Adsorption of silver-component in x-ray fkcr wastewater was carricd out this study. 'Ille manganese dioxide (MDO) reagent and the recovered manganese dioxide (RMDO) from the waste dry-cell were used for adsarbents. Adsorption of silvercomponent was wrried out at the batch and continuous type experimental equipment. The adsorption experiment results were obtained bom silver-component have some diifcrences according to adsorhents. The adsorption results of manganese dioxide reagent (MDO) were better ihan those of waste dry-ccU (RMDO), but the manganese dloxide recovered fmm waste dry-cell (RMDO) will be able la recognized as good adsorbent too.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.1
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• pp.33-41
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• 2007

Bone scan using radioactive isotope can be more effective than conventional X-ray radiograph for finding jaw lesion because it takes an image of the physiologic change of bone. This study is designed to show how available bone scan is able to diagnose jaw lesion better than simple X-ray and CT, as well as to determine a basis of diagnosis for jaw lesion using bone scan. The 77 patients, visiting the Oral & Maxillofacial Surgery, Department of Dankook University Hospital from January 2002. to August 2005. who were diagnosed histopathologically with postoperative malignant tumor, osteomyelitis, and bone infiltrative benign disease. Preoperative X-ray, CT, bone scan were taken and were compared with histopathologic finding. Also to compare specificty of each lesion in bone scan, bone density was measured to compare. The results were as follows. 1. Among the 25 cases of oral malignant tumor of bony invasion, a positive diagnosis associated with histopathologic evaluation, 22 cases(88%) in bone scan, 14 cases(56%) in CT image, and 10 cases40%) in simple X-ray. 2. Among the 31 cases of osteomyelitis, a positive diagnosis associated with histopathologic evaluation, 30 cases(97%) in bone scan, 23 cases(74%) in CT image, and 19 cases(61%) in simple X-ray. 3. Among the 11cases of bone infiltrative benign disease, a positive diagnosis associated with histopathologic evaluation, 11 cases(100%) in bone scan, 10 cases(91%) in CT image, and 6 cases(55%) in simple X-ray. 4. Measurement of bone density in each group showed no statistical significant difference between malignant tumor and osteomyelitis as well as benign bone disease. But, a statistical significance was seen between osteomyelitis and benign bone disease. From this results, bone scan are more sensitive than simple X-ray and CT image in jaw lesion diagnosis, but specificity shows no significant difference. Therefore, it should be suggested that evaluation of bone scan must be carrying out in reference to final histopathologic diagnosis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.12
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• pp.797-802
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• 2014

In this study, in order to develop the capacitor composition ceramics with the good dielectric properties, $(Ba_{1-x}Ca_x)(Ti_{0.85}Zr_{0.12}Sn_{0.03})O_3$ (abbreviated as BCTZ) ceramics were prepared by the conventional solid-state reaction method. The effects of Ca substitution on the microstructure and dielectric properties was investigated. The X-ray diffraction patterns demonstrated that all the specimens showed perovskite phase, and secondary phases are indicated in the measurement range of X-ray diffraction. Also, all the specimens indicated an rhombohedron phase structure. It was identified from the X-ray diffraction patterns that the secondary phase formed in grain boundaries and then decreased the dielectric properties. For all the specimens, observed one peak was tetragonal cubic phase transition temperature($T_c$), which is located in the vicinity of room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11b
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• pp.15-17
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• 2004

The quality of X -ray image is depending on the acquired signal pattern So far, the MTF(modulation transfer function) of medical image system has been obtained through various kinds of calculationprocesses after using SWRF (A square wave response function method) to print out it into films. In this study, a tool has been developed that can help the actual user who actually creates the medical images measure the MTF of the finaldisplay image very simply by applying Borland C++ builder software as well as LEAD tools software for the SWRF calculation process to analyze the MTF even on the display image. Films have been printed out by this newly developed MTF measuring tool under the same conditions with the ones for the existing tools and also the calculation method has shown no difference with any existing SWRF calculation method. By using this, it was found out that the MTF of the resolving power of the computed radiography(CR) Image plate (IP) that is a conventional X-ray detection system Jar the conventional X-ray purpose was about 10% at the range of 3.00 LP/mm.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2002.11a
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• pp.97-117
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• 2002

A chemoinfometrical method for quantitative determination of crystal content of indomethacin (IMC) polymorphs based on fourie-transformed near-infrared (FT-NIR) spectroscopy was established. A direct comparison of the data with the ones collected from using the conventional powder X-ray diffraction method was performed. Pure $\alpha$ and ${\gamma}$ forms of IMC were prepared using published methods. Powder X-ray diffraction profiles and NIR spectra were recorded for six kinds of standard materials with various content of ${\gamma}$ form IMC. The principal component regression (PCR) analyses were performed based on normalized NIR spectra sets of standard samples of known content of IMC ${\gamma}$ form. A calibration equation was determined to minimize the root mean square error of the prediction. The predicted ${\gamma}$ form content values were reproducible and had a relatively small standard deviation. The values of ${\gamma}$ form content predicted by two methods were in close agreement. The results were indicated that NIR spectroscopy provides for an accurate quantitative analysis of crystallinity in polymorphs compared with the results obtained by conventional powder X-ray diffractometry.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.741-745
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• 1991

This paper describes a feature extraction in digitized chest X-ray image and CT head Image. There are Extraction, Thresholding, Region G rowing, Split-Merge and Relaxation in feature extraction technique. In this study, Region Growing System was realized and Fuzzy Set Theory was applied in order to extract the vague region which the conventional method has difficulties in extracting. The performance of proposed algorithm was proved by being applied to chest X-ray image and CT head image.