• Journal of the Optical Society of Korea
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• v.17 no.1
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• pp.38-43
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• 2013

In this study, we propose a simple and indirect method to determine the optical constants of Mo and ITO thin films in the extreme ultraviolet (EUV) wavelength region by using X-ray reflectometry (XRR) and Rutherford backscattering spectrometry (RBS). Mo and ITO films were deposited on silicon substrates by using an RF magnetron sputtering method. The density and the composition of the deposited films were evaluated from the XRR and RBS analysis, respectively and then the optical constants of the Mo and ITO films were determined by an indirect optical method. The results suggest that the indirect method by using the XRR and RBS analysis will be useful to search for suitable high absorbing EUVL mask material quickly.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.51-62
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• 1993

A computational program ［TDET］ of the particle transport equation is developed on radiation shielding problem in two-dimensional cartesian geometry based on the discrete element method. Not like the ordinary discrete ordinates method, the quadrature set of angles is not fixed but steered by the spatially dependent angular fluxes. The angular dependence of the scattering source term in the particle transport equation is described by series expansion in spherical harmonics, and the energy dependence of the particles is considered as well. Three different benchmark tests are made for verification of TDET : For the ray effect analysis on a square absorber with a flat isotropic source, the results of TDET calculation are quite well conformed to those of MORSE-CG calculation while TDET ameliorates the ray effect more effectively than S$_{N}$ calculation. In the analysis of the streaming leakage through a narrow vacuum duct in a shield, TDET shows conspicuous and remarkable results of streaming leakage through the duct as well as MORSE-CG does, and quite better than S$_{N}$ calculation. In a realistic reactor shielding situation which treats in two cases of the isotropic scattering and of linearly anisotropic scattering with two groups of energy, TDET calculations show local ray effect between neighboring meshes compared with S$_{N}$ calculations in which the ray effect extends broadly over several meshes.eshes.

• Journal of radiological science and technology
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• v.28 no.2
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• pp.111-115
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• 2005

The quality of image from the system that creates medical images by using X-ray depends on the various different reasons such as the X-ray generator, the subject and the image transmission medium. In other words, thereare various factors existing that can influence on the quality of image from the moment when the X-ray is generated and until the final image is created. Therefore, the operator who creates images at the clinical site should make continuous evaluation and observation from the final image. There are various methods of evaluating the medical images, but it is assumed that the MTF measurement method can be suitable for measuring actual or effective resolution. So in this study, the MTF measurement method by using X-ray film has been avoided and the MTF features according to the deterioration of the X-ray system have been measured by using the software (the program used Borland C++ builder software and LEAD tools software) that can measure the MTF of the digital medical images. As the result of this measurement, it has been found out through the MTF graph that the resolution and sharpness from the old x-ray generator with a many years of using and many numbers of times of using were deteriorated for the quality of image comparing to those from the new system. Also a simple and easy measurement method for the MTF from the digital medical images can be obtained in this study.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.105-111
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• 2018

Purpose Quality control of instrument takes up a large part in the Radioimmunoassays. The gamma-ray instrument, which is one of the important instruments in the laboratory, observes the condition and performance of instrument and performs quality control of the instrument by measuring the Normalization, Calibration, Background and etc. However, there are some automation instruments which can't measure the counting efficiency of gamma-ray meters, resulting in insufficient management in terms of performance evaluation of gamma-ray meters. Therefore, the purpose of this paper is to manage the quality control continuously and regularly by suggesting how to measure the counting efficiency of gamma-ray instruments. Materials and Methods In case of a comparative measurement method to a gamma-ray instrument dedicated to nuclear medical examination, the CPM and counting efficiency can be obtained after the measurement of normalization by inserting the I-125 $200{\mu}L$(CPM 50,000~500,000) into the test tube. With this CPM and counting efficiency values, it's possible to calculate the measurement of the DPM value and count the CPM from the automation instrument from the same source, and enter the DPM to calculate the counting efficiency using a comparative measurement method. Another method is to calculate the counting efficiency by estimating the half life using the radiation source information of the tracer in B test reagents of company A. Results According to the calculation formula using the DPM obtained by counting the normalization of gamma-ray meters, the detection efficiency was 75.16% for Detector 1, 76.88% for Detector 2, 77.13% for Detector 3, 75.36% for Detector 4 and 73.2% for Detector 5 respectively. Using another calculation formula estimated from the shelf life, the data of the detection efficiency from Detector 1 to Detector 5 were 74.9%, 75.1%, 76.5%, 74.9% and 73.2% respectively. Conclusion Although the accuracy of counting efficiencies of both methods are insufficient, this is considered to be useful for ongoing management of quality control if counting efficiency is managed after setting the acceptable ranges. For example, if the measurement efficiency is set to 70% or higher, the allowed %difference between measurements is within 3% and the %difference with the detector wall is set within 5%.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1442-1448
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• 2012

The problem of Metal Area Segmentation (MAS) in X-ray CT images is a very hard task because of metal artifacts. This research features a practical yet effective method for MAS in X-ray CT images that exploits both projection image and reconstructed image spaces. We employ the Relevant Neighbor Area (RNA) idea [1] originally developed for projection image inpainting in order to create a novel feature in the projection image space that distinctively represents metal and near-metal pixels with opposite signs. In the reconstructed result of the feature image, application of a simple thresholding technique provides accurate segmentation of metal areas due to nice separation of near-metal areas from metal areas in its histogram.

• Journal of Pharmaceutical Investigation
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• v.21 no.3
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• pp.125-132
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• 1991

Using X-ray crystallography powder diffraction, the quantitative representation method of preferred orientation of particles ill tablets was developed. Selected faces of a tablet. the upper surface and faces cut parallel and normal to the upper surface, were presented to an X-ray beam and X-ray diffraction patterns for these faces were measured. The effects of particle size. tableting pressure, and particle form on the preferred orientation were also investigated. It was also recognized that the degree of anisotropy in terms of capping tendency was influenced by the preferred orientation of particles in tablets.

• Journal of Korea Foundry Society
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• v.26 no.3
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• pp.129-132
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• 2006

In the present study the new method was proposed by using the real-time X-ray observation and metal die in order to evaluate fluidity and viscosity of the molten metal during pouring into the mold. The special mold for the present experiment was introduced since X-ray could not transmit thick mold wall and scatter the image of the molten metal during pouring. The present study also discussed for evaluation of viscosities by using the flow data from radioscopy images, and the viscosities of six commercial aluminum alloys were evaluated and compared.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.845-848
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• 2002

The study of photoconductor materials is demanded for development for flat-panel digital x-ray Imager. In this paper, We investigated the feasibility of application as x-ray image sensor using Cd(Zn)Te compound with high stopping power on high radiation. These Cd(Zn)Te samples were fabricated by vacuum thermal evaporation method to large area deposition and investigated I-V measurement as applied voltage. The experimental results show that the additional injection Zn in CdTe film reduced the leakage current, for the $Cd_{0.85}Zn_{0.15}Te$ detector, the net charge had the highest value as $144.58pC/cm^2$ at 30 V.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.281-283
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• 2005

Processing Plasmas are very sensitive to a variation in process parameters, To maintain process quality and device field, plasma malfunction should be tightly monitored with high sensitivity. A new monitoring method is presented and this was accomplished by applying discrete wavelet transformation to X-ray photoelectron spectroscopy. XPS data were collected during a plasma etching of silicon carbide. Various effects of DWT factor on fault sensitivity were optimized experimentally. Compared to raw data, total percent sensitivity for DWT data demonstrated a significantly improved sensitivity to plasma faults induced by bias power.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.3
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• pp.60-65
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• 2006

This paper proposes a new type of six degree-of-freedom fine positioner that can be used to align the condenser in X-ray microscopy precisely. The new concept was based on the requirements for an X-ray microscope. A proposed modeling method was used to obtain an optimal design, which was verified with a finite element analysis. The fine positioner was then constructed and an experiment was used to validate its performance.