• Composites Research
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• v.34 no.3
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• pp.143-147
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• 2021

Full width half maximum (FWHM) analysis of superimposed terahertz (THz) signals in the glass fiber reinforced polymer (GFRP) was studied to detect fine delamination inside GFRP. The THz signals were measured for each fine delamination size inside the GFRP using the reflection mode of the terahertz time domain spectroscopy (THz-TDS) system. Then, the FWHM of the superimposed THz signal reflected at the fine delamination was extracted. Thereafter, the complex refractive index of the GFRP was measured using transmission mode of the THzTDS system. Based on this, the FWHM of the superimposed THz signal at the fine delamination were calculated and compared with respect to the fine delamination size. From the theoretically calculated superimposed signals, the relationship between the fine delamination size and the FWHM in the superimposed THz signal was derived. Consequently, the fine delamination size could be predicted through the analysis of the FWHM extracted from the THz signal at the fine delamination.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.69-76
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• 2010

Prototype double-scattering Compton camera, which consists of three gamma-ray detectors, that is, two double-sided silicon strip detectors (DSSDs) as scatterer detectors and a NaI(Tl) scintillation detector as an absorber detector, could provide high imaging resolution with a compact system. In the present study, the energy resolution and the timing resolution of component detectors were measured, and the parameters affecting the energy resolution of the DSSD were examined in terms of equivalent noise charge (ENC). The energy resolutions of the DSSD-1 and DSSD-2 were, in average, $25.2keV{\pm}0.8keV$ FWHM and $31.8keV{\pm}4.6keV$ FWHM at the 59.5 keV peak of $^{241}Am$, respectively. The timing resolutions of the DSSD and NaI(Tl) scintillation detector were 57.25 ns FWHM and 7.98 ns FWHM, respectively. In addition, the Compton image was obtained for a point-like $^{137}Cs$ gamma source with double-scattering Compton camera. From the present experiment, the imaging resolution of 8.4 mm FWHM (angular resolution of $8.1^{\circ}$ FWHM), and the imaging sensitivity of $1.5{\times}10^{-7}$ (intrinsic efficiency of $1.9{\times}10^{-6}$) were obtained.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.30-34
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• 2009

Purpose: Many companies developed a lot of programs with continuous effort for program upgrading. With this acquire superior image quality for the purpose of quick examination and progress in spatial resolution. This study was to obtained clinical usefulness on a appropriate parameter of FWHM for speed and alpha value for superior image quality. Materials and Methods: Gamma camera by Siemens (e.cam) and spatial resolution phantom and four quadrant bar phantom used. Compared for FWHM by changed scan speed 15, 20, 25, 30, 35, 40 cm/min in scatter and non scatter in Onco Flash of spatial resolution phantom. Visual evaluation of count rate and bar phantom image for increased of alpha value of 10% in 0~100%. Results: FWHM by the scan speed was 9.37, 9.40, 9.28, 9.30, 9.31, 9.53 mm in the scatter. Count rate increased alpha value 10% increased. Visual evaluation was suitable to below 30%, Therefore spatial resolution improved on FWHM at the scan speed 25~35 cm/min applying for alpha value 30% in Onco Flash was average 9.3 mm less than FWHM of below 15 cm/min and above 40 cm/min. Conclusion: We found on appropriate parameter to progress of image quality. And there be a useful guideline for you that appropriate scan speed on vary in parameters of reduction on examination time and advancing image quality.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.841-845
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• 2020

An airborne alpha beta detection system using passivated implanted planar silicon (PIPS) detector was modeled with the MCNP6 code and its resolution and detection efficiency were analyzed. Simulation of the resolution performed using the Gaussian energy broadening (GEB) function showed that the full width at half maximum (FWHM) of 35.214 keV for alpha particles was within 34-38 KeV, which is the FWHM range of the actual detector, and the FWHM of 15.1 keV for beta particles was constructed with a similar model to 17 keV, which is the FWHM range of an actual detector. In addition, the detection efficiency and the resolution were simulated according to the distance between the detector and the air filter. When the distance was decreased to 0.2 cm from 0.8 cm, the efficiency of the alpha and beta particles detection decreased from 5.33% to 4.89% and from 5.64% to 4.27%, respectively, and the FWHM of the alpha and beta particles improved from 40.9 KeV to 29.84 keV and 25.76 keV-13.27 keV, respectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.5
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• pp.539-544
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• 2002

The purpose of this study is to examine the change of full width half maximum(FWHM) and residual stress during fatigue process in S45C Steel, by X-ray diffraction. For S45C Steel, the relationship between the change in fatigue damage of the specimen and the FWHM, and residual stress of X-ray diffraction profiles during the fatigue processes has been investigated. The FWHM decreases in the early period of fatigue cycle. The change of FWHM is associated with cyclic work hardening. The change of the FWHM is not significant in $10{\sim}20%$ of ratio of fatigue life. The residual stress is changed with fatigue cycle increasing during the fatigue pro process.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.1
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• pp.15-33
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• 2021

In this study, the possibility of discriminating Fire blight (FB) infection tested using the hyperspectral imagery. The reflectance of healthy and infected leaves and branches was acquired with 5 nm of full width at high maximum (FWHM) and then it was standardized to 10 nm, 25 nm, 50 nm, and 80 nm of FWHM. The standardized samples were divided into training and test sets at ratios of 7:3, 5:5 and 3:7 to find the optimal bands of FWHM by the decision tree analysis. Classification accuracy was evaluated using overall accuracy (OA) and kappa coefficient (KC). The hyperspectral reflectance of infected leaves and branches was significantly lower than those of healthy green, red-edge (RE) and near infrared (NIR) regions. The bands selected for the first node were generally 750 and 800 nm; these were used to identify the infection of leaves and branches, respectively. The accuracy of the classifier was higher in the 7:3 ratio. Four bands with 50 nm of FWHM (450, 650, 750, and 950 nm) might be reasonable because the difference in the recalculated accuracy between 8 bands with 10 nm of FWHM (440, 580, 640, 660, 680, 710, 730, and 740 nm) and 4 bands was only 1.8% for OA and 4.1% for KC, respectively. Finally, adding two bands (550 nm and 800 nm with 25 nm of FWHM) in four bands with 50 nm of FWHM have been proposed to improve the usability of multispectral image sensors with performing various roles in agriculture as well as detecting FB with other combinations of spectral bands.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.322-331
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• 2009

In clinical SPECT, FWHM provides quality information of the images obtained under different observing conditions. Therefore, the purpose of this study was to determine the optimum cut off level with comparison of FWHM according to cut off levels in each filter - Band limited, Sheep-Logan, Hanning, Hamming, Low pass cosine, Parazen and Butterworth filter in a SPECT camera. I recorded images along the X, Y, Z-axis with 99mTcO4 point source and measured FWHM with profile curves. In conclusion, all filters showed the longest figures of FWHM with cut off level 0.4, which has the worst image resolution. The images with cut off level 0.7 showed best image resolution. The shortest average of FWHM in MS2 was $11.07\pm0.07mm$ using the Butterworth filter, in MS3 it was $8.44\pm0.19mm$ through using the Hanning filter.

• Journal of radiological science and technology
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• v.25 no.1
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• pp.77-81
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• 2002

The purpose of this study is to examine quantitatively the relationship between visual image quality and degradation In spatial resolution for a gamma camera by the increase in distance from collimator. The relationship between the portion(p) of images identified the difference of image quality and the difference(${\Delta}FWHM$) in FWHM between paired images was showed in a sigmoid curve. Using Dendy's method, minimum level to be correctly identified the difference of Image duality on three out of four occasion(p=0.75) was corresponded to 0.4 mm in ${\Delta}FWHM$. Using fuzzy theory, the level to be identified the difference of image quality was examined under various conditions. The truth-value of fuzzy sets-degraded or slightly degraded and not-degraded in image quality between palled Images-was gained the peak at 0.5 mm of ${\Delta}FWHM$. It was founded that changes of $0.4{\sim}0.5\;mm$ in FWHM-corresponding about 2 cm distance from collimator could be sufficiently identified in the difference of image quality.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.104-109
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• 2014

Purpose: Conventional pinhole scintigraphy offers a high resolution and generally use for thyroid scan or bone scintigraphy. the aim of this study is to evaluate performance of each aperture according to the diameter size. Materials and Methods: In this study 2 mm, 4 mm, 6 mm, 8 mm diameter pinhole collimators were mounted on Siemens E.CAM systems. In order to evaluate performance evaluation of each aperture, we acquired projection image by using SPECT for evaluating FWHM, resolution test and static image for evaluating thyroid phantom test. Results: As a result of FWHM showed 2.2 mm FWHM, 3.2 mm FWHM, 5.4 mm FWHM, 7.5 mm FWHM per each aperture in the resolution test. SNR, uniformity, contrast were acquired result from thyroid phantom test comparing general image and delayed image. as a result of SNR showed 6.55, 8.47, 6.2, 5.23 in case of general image and 5.25, 5.01, 5.38, 5.82 in case of delayed image per each aperture. as a result of uniformity showed 0.152, 0.118, 0.161, 0.19 in case of general image and 0.19, 0.199, 0.185, 0.171 in case of delayed image per each aperture. as a result of contrast showed 1.31, 1.19, 1.15, 1.01 in case of general image and 1.09, 1.08, 1.04, 1 in case of delayed image per each aperture. Conclusion: Resolution and sensitivity were heavily influenced by aperture size. and also we found advantage of delayed image as a result of thyroid phantom test.

• Journal of Magnetics
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• v.21 no.1
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• pp.35-39
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• 2016

$Cr_{100-x}Ti_x$ amorphous texture-inducing layers (TIL) were investigated to realize highly (002) oriented $L1_0$ FePt-C granular films through hetero-epitaxial growth on the (002) textured bcc-$Cr_{80}Mn_{20}$ seed layer (bcc-SL). As-deposited TILs showed the amorphous phase in Ti content of $30{\leq}x(at%){\leq}75$. Particularly, films with $40{\leq}x{\leq}60$ kept the amorphous phase against the heat treatment over $600^{\circ}C$. It was found that preference of the crystallographic texture for bcc-SLs is directly affected by the structural phase of TILs. (002) crystallographic texture was realized in bcc-SLs deposited on the amorphous TILs ($40{\leq}x{\leq}70$), whereas (110) texture was formed in bcc-SLs overlying on crystalline TILs (x < 30 and x > 70). Correlation between the angular distribution of (002) crystal orientation of bcc-SL evaluated by full width at half maximum of (002) diffraction (FWHM) and a grain diameter of bcc-SL indicated that while the development of the lateral growth for bcc-SL grain reduces FWHM, crystallization of amorphous TILs hinders FWHM. $L1_0$ FePt-C granular films were fabricated under the substrate heating process over $600^{\circ}C$ with having different FWHM of bcc-SL. Hysteresis loops showed that squareness ($M_r/M_s$) of the films increased from 0.87 to 0.95 when FWHM of bcc-SL decreased from $13.7^{\circ}$ to $3.8^{\circ}$. It is suggested that the reduction of (002) FWHM affects to the overlying MgO film as well as FePt-C granular film by means of the hetero-epitaxial growth.