• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3459-3469
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• 2022

Matrix composites of n-WO₃/n-Bi₂O₃/PVA with different loadings of n-WO₃/n-Bi₂O₃ mixtures (0-15 wt%) and starch (0 and 3 wt%) were fabricated by using melt-mixing method. The X-ray attenuation capability were evaluated based on mass attenuation coefficient (μ/⍴) using a general diagnostic X-ray machine at 40-100 kVp. The effect of starch addition on the dispersion of the fillers in the PVA matrix were observed by using FESEM through morphological analysis. The fabricated samples have shrunken and caused their thickness to be decreased (0.35 mm-0.55 mm) after the drying process even though fixed thickness (2.0 mm) was set initially. The density and HVL values of the samples with 3 wt% starch was seen lower than samples without starch (0 wt%), however the former have provided improvement in filler dispersion and better X-ray attenuation capability compared to the latter. As conclusion, the matrix composite of n-WO₃/n-Bi₂O₃/PVA with 15 wt% of n-Bi₂O₃, 8 wt% of n-WO₃ and 3 wt% starch can be selected as the best promising candidate for X-ray shielding materials.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4684-4692
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• 2022

Radionuclide identification is an important part of the nuclear material identification system. The development of artificial intelligence and machine learning has made nuclide identification rapid and automatic. However, many methods directly use existing deep learning models to analyze the gamma-ray spectrum, which lacks interpretability for researchers. This study proposes an explainable radionuclide identification algorithm based on the convolutional neural network and class activation mapping. This method shows the area of interest of the neural network on the gamma-ray spectrum by generating a class activation map. We analyzed the class activation map of the gamma-ray spectrum of different types, different gross counts, and different signal-to-noise ratios. The results show that the convolutional neural network attempted to learn the relationship between the input gamma-ray spectrum and the nuclide type, and could identify the nuclide based on the photoelectric peak and Compton edge. Furthermore, the results explain why the neural network could identify gamma-ray spectra with low counts and low signal-to-noise ratios. Thus, the findings improve researchers' confidence in the ability of neural networks to identify nuclides and promote the application of artificial intelligence methods in the field of nuclide identification.

• Geophysics and Geophysical Exploration
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• v.2 no.4
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• pp.167-173
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• 1999

Since the resolution of the 2-D hole-to-hole seismic traveltime tomography is affected by the limited ray transmission angle, various methods were used to improve the resolution. Linear traveltime interpolation(LTI) ray tracing method was chosen for forward-modeling method. Inversion results using the LTI method were compared with those using the other ray tracing methods. As an inversion algorithm, SIRT method was used. In the iterative non-linear inversion method, the cost of ray tracing is quite expensive. To reduce the cost, each raypath was stored and the inversion was performed from this information. Using the proposed method, fast convergence was achieved. Inversion results are likely to be affected by the initial velocity guess, especially when the ray transmission angle was limited. To provide a good initial guess for the inversion, generalized regression neural network(GRNN) method was used. When the transmitted raypath angle is not limited or the geological model is very complex, the inversion results are not affected by initial velocity model very much. Since the raypath angles, however, are limited in most geophysical tomographic problems, the enhancement of resolution in tomography can be achieved by providing a proper initial velocity model by another inversion algorithm such as GRNN.

• Journal of Korea Water Resources Association
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• v.52 no.1
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• pp.51-60
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• 2019

The major purpose of this study is to construct an in-situ soil moisture verification network employing Frequency Domain Reflectometry (FDR) sensors for Cosmic-ray soil moisture observation system operation as well as long-term field-scale soil moisture monitoring. The test bed of Cosmic-ray and FDR verification network system was established at the Sulma Catchment, in connection with the existing instrumentations for integrated data provision of various hydrologic variables. This test bed includes one Cosmic-ray Neutron Probe (CRNP) and ten FDR stations with four different measurement depths (10 cm, 20 cm, 30 cm, and 40 cm) at each station, and has been operating since July 2018. Furthermore, to assess the reliability of the in-situ verification network, the volumetric water content data measured by FDR sensors were compared to those calculated through the core sampling method. The evaluation results of FDR sensors- measured soil moisture against sampling method during the study period indicated a reasonable agreement, with average values of $bias=-0.03m^3/m^3$ and RMSE $0.03m^3/m^3$, revealing that this FDR network is adequate to provide long-term reliable field-scale soil moisture monitoring at Sulmacheon basin. In addition, soil moisture time series observed at all FDR stations during the study period generally respond well to the rainfall events; and at some locations, the characteristics of rainfall water intercepted by canopy were also identified. The Temporal Stability Analysis (TSA) was performed for all FDR stations located within the CRNP footprint at each measurement depth to determine the representative locations for field-average soil moisture at different soil profiles of the verification network. The TSA results showed that superior performances were obtained at FDR 5 for 10 cm depth, FDR 8 for 20 cm depth, FDR2 for 30 cm depth, and FDR1 for 40 cm depth, respectively; demonstrating that those aforementioned stations can be regarded as temporal stable locations to represent field mean soil moisture measurements at their corresponding measurement depths. Although the limit on study duration has been presented, the analysis results of this study can provide useful knowledge on soil moisture variability and stability at the test bed, as well as supporting the utilization of the Cosmic-ray observation system for long-term field-scale soil moisture monitoring.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.4
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• pp.259-267
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• 2002

We present a novel 3D fabrication method with single X-ray process utilizing an X-ray mask in which a micro-actuator is integrated. An X-ray absorber is electroplated on the shuttle mass driven by the integrated micro-actuator during deep X-ray exposures. 3D microstructures are revealed by development kinetics and modulated in-depth dose distribution in resist, usually PMMA. Fabrication of X-ray masks with integrated electrothermal xy-stage and electrostatic actuator is presented along with discussions on PMMA development characteristics. Both devices use $20-\mu\textrm{m}$-thick overhanging single crystal Si as a structural material and fabricated using deep reactive ion etching of silicon-on-insulator wafer, phosphorous diffusion, gold electroplating, and bulk micromachining process. In electrostatic devices, $10-\mu\textrm{m}-thick$ gold absorber on $1mm{\times}1mm$ Si shuttle mass is supported by $10-\mu\textrm{m}-wide$, 1-mm-long suspension beams and oscillated by comb electrodes during X-ray exposures. In electrothermal devices, gold absorber on 1.42 mm diameter shuttle mass is oscillated in x and y directions sequentially by thermal expansion caused by joule heating of the corresponding bent beam actuators. The fundamental frequency and amplitude of the electrostatic devices are around 3.6 kHz and $20\mu\textrm{m}$, respectively, for a dc bias of 100 V and an ac bias of 20 VP-P (peak-peak). Displacements in x and y directions of the electrothermal devices are both around $20{\;}\mu\textrm{m}$at 742 mW input power. S-shaped and conical shaped PMMA microstructures are demonstrated through X-ray experiments with the fabricated devices.

• Korean journal of applied entomology
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• v.33 no.4
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• pp.263-269
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• 1994

A method to control the cigarette beetle. Losioderma serricorne F, m cigarettes by using gamma ray irradiation was evaluated When all stages of cigarette beetle were placed in gelatin capsules and irradiated wlth gamma ray. no eggs survived, but mortalities of pupae, larvae and adults exposed to above 0.8 kGy of gamma ray were only from 0 to 30%. Similar results were also obtained in the control efficacy of the beetle when seuqal kinds ot currently produced ngarettes containing m gelatin capsules were inadhated with gamma ray The cigarette beetle adults and larvae surviving gamma ray inadiatlon were reared on artificial d~etsto show that there were no reproduc. tions was observed in the second generation. The survival periods for each growth stage became shoter with increase gamma ray dosage. The fouirh instar larvae had the longest sulvlvai periods No sign~ficant changes of cigarette flavor and taste were noticed alter gamma ray inadiation. The cigarette packet, metal fotl for packet and cigarette paper by the inad~atlon were not discolored by irradiation.

• The Journal of Pediatrics of Korean Medicine
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• v.22 no.2
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• pp.155-170
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• 2008

Objectives : The purpose of this study was to have better data and to make efficient clinical reviews about children's growth based on two methods; X-ray of hand, and ultrasound of calcaneus. Methods : The study was composed of 100 patients(50 of boys and 50 of girls) who visited in department of pediatrics, O O university oriental hospital considering growth and their development. Bone age was measured by the TW3 method's RUS score in simple X-ray image of hand and bone density through ultrasonic image of calcaneus. To predict children's estimated height, their parent's height, bone age, and present height's percentile was measured. Results and Conclusions : 1. The bone age results from X-ray image of hand and ultrasonic image of calcaneus were correlated. Younger children have older bone age from hand's X-ray than the one from calcaneus's ultrasound. Older children have older bone age from calcaneus's ultrasound than one from hand's X-ray. 2. Predicted adult height by bone age(BH) of hand's X-ray and BH of calcaneus's ultrasound were correlated, but predicted adult height by inheritance(IH) was not correlated with others. 3. Bone age and predicted adult height were correlated with age, height, weight, BMI, and especially with age and height. 4. Measuring bone age by X-ray image of hand and ultrasonic image of calcaneus was simple and effective way of estimating children's growth and development.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.773-775
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• 2010

Diagnostic X-ray high voltage generator needs high voltage input power when operated, if electric power conditions are not suitable, could not use diagnostic X-ray high voltage generator or could not use normally by abnormal working. If diagnostic X-ray system operated with abnormally by electric power conditions, it cause of difficulty of patient diagnosis. And we used auxiliary power with battery to operate diagnostic X-ray high voltage generator without using normal electric power. We made one device after designing of new electric circuit and we compared normal power X-ray system with battery powered X-ray system by described method in this thesis. And then we found characteristic and efficiency of diagnostic X-ray high voltage generator by different input power condition.

• Journal of the Korean Ceramic Society
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• v.33 no.8
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• pp.928-934
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• 1996

Quantitative analysis each portland cement components was conducted by standard calibration method using X-ray fluorescence spectrometer. Standard sample and the unknown sample were prepared by fused cast bead method. In checking the errors of standard cement 227A372 the relative errors of constituents such as CaO, SiO2, Al2O3, Fe2O3, MgO and SrO were less than 1% and the relative errors of constituents such as So3, K2O, TiO2, Na2O P2O5, and Mn2O3 were less than 5% Sample preparation was mainly contributed to the errors. Compared with general wet chemical method the results of X-ray fluorescence analyses were more precise and accurate. Moreover it is possible to analyze precisely a little amount of the constituents such as SrO, Mn2O3 and P2O5 the analyses of which were very difficult using the wet chemical method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.101-112
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• 1985

It is important to extract the mechanical informations from the image sequences of the moving object. We have studied the computer algorithms for analysis of the moving heart using X-ray image sequence. A new mathematical method was developed to estimate the local epicardial deformation, wall thickness, and the regional circumferential and longitudinal wall stress using biplane coronary cineangiograms. In this method, the motion images of the coronary artery bifurca-tion points were used as natural landmarks for the kinematic analysis of the ventricular deformation. In four dogs and a normal patient's coronary cineangiograms, the estimation results show the validity of the present analysis, compared with the experimental results based upon the implanted markers. Thus, the present method provides a new method of evaluating the regional wall deformation and wall stress together with the blood vessel conditions using the coronary cineangiography procedure.