• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1849-1854
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• 2018

The present study aims to investigate the feasibility of using a simple nonlinear acoustic method for the assessment of bone status and osteoporosis in trabecular bone. Correlations of linear and nonlinear ultrasound parameters with the apparent bone density were obtained in 32 bovine femoral trabecular bone samples. Highly significant positive correlations were observed between the apparent bone density and the two linear ultrasound parameters, the speed of sound (SOS) and the normalized broadband ultrasound attenuation (nBUA), with Spearman's correlation coefficients of r = 0.85 and 0.77. In contrast, the apparent bone density was found to be negatively correlated with the nonlinear ultrasound parameter introduced in the present study, the logarithmic difference between the power spectrum levels of the fundamental frequency and the second harmonic (PSL1-PSL2), with the highest correlation coefficient of r = -0.92. These results suggest that the PSL1-PSL2, in addition to the SOS and the nBUA, may be useful for the assessment of bone status and osteoporosis.

• Food Science and Preservation
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• v.13 no.1
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• pp.55-60
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• 2006

Two kinds of composite seasoning products (beef broth powder, polk bone extract powder) were used for a detection trial of gamma irradiation treatment up to 10 kGy by analyzing photostimulated luminescence (PSL), electron spin resonance (ESR) and thermoluminescence(TL). PSL results showed that the photon counts of non-irradiated samples were lower than 700, while those of irradiated samples were higher than 5000, which makes it possible to screen irradiated composite seasoning products at 1 kGy or over from the non-irradiated control. ESR signals measured for both irradiated samples were not irradiation-specific, even though they were dose dependent in the signal intensity. Radiation-induced TL glow curves were found in irradiated beef broth powder and furthernmore, TL ratio $(TL_4/TL_2)$ obtained by a re-irradiation step could verify the detection result of TL1 glow curves, showing ratios lower than 0.05 in the non-irradiated sample and higher than 1.00 in irradiated ones.

• Food Science and Preservation
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• v.13 no.1
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• pp.61-65
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• 2006

Photostimulated luminescence (PSL), thermoluminescence(TL) and electron spin resonance (ESR) analyses were conducted to detect irradiation treatment of aloe vera powder, which was gamma-irradiated at 1, 3, 5 and 7 kGy. The non-irradiated aloe vera powder indicated below 700 of photon count in PSL, whereas, irradiated at 1 kGy and more, it showed more than 5,000 photon counts, indicating that it is feasible to detect the irradiation of aloe vera powder through PSL In the result of TL, from the minerals of the samples that were irradiated at more than 1 kGy, TL glow curve was able to be seen at around $150^{\circ}C$. As the quantity of irradiation goes up, the ratio of $TL_1\;and\;TL_2$ also increased in proportion to that of irradiation. In the result of ESR analysis, unspecific centeral ESR signal was could be seen. As the amount of irradiation on the samples increased to the level of $R^2=0.97$, the signal intensity also rose similarly. In conclusion, the PSL, TL and ESR exhibited the typical signals induced by irradiation treatment and were able to successfully detect all of the irradiated aloe vera powder. In addition, we found a positive correlation between the intensity of ESR and TL signals and irradiation doses.

• Bulletin of the Korean Mathematical Society
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• v.50 no.2
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• pp.601-610
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• 2013

In [3] and [2], Atanassov introduced the two arithmetic functions $$I(n)=\prod_{p^{\alpha}{\parallel}n}\;p^{1/{\alpha}}\;and\;R(n)=\prod_{p^{\alpha}{\parallel}n}\;p^{{\alpha}-1}$$ called the irrational factor and the restrictive factor, respectively. Alkan, Ledoan, Panaitopol, and the authors explore properties of these arithmetic functions in [1], [7], [8] and [9]. In the present paper, we generalize these functions to a larger class of elements of $PSL_2(\mathbb{Z})$, and explore some of the properties of these maps.

• Bulletin of the Korean Mathematical Society
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• v.51 no.2
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• pp.443-455
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• 2014

Atanassov introduced the irrational factor function and the strong restrictive factor function, which he defined as $I(n)=\displaystyle\prod_{p^{\alpha}||n}^{}p^{1/{\alpha}}$ and $R(n)=\displaystyle\prod_{p^{\alpha}||n}^{}p^{{\alpha}-1}$ in [2] and [3]. Various properties of these functions have been investigated by Alkan, Ledoan, Panaitopol, and the authors. In the prequel, we expanded these functions to a class of elements of $PSL_2(\mathbb{Z})$, and studied some of the properties of these maps. In the present paper we generalize the previous work by introducing real moments and considering a larger class of maps. This allows us to explore new properties of these arithmetic functions.

• Corrosion Science and Technology
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• v.23 no.2
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• pp.93-103
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• 2024

In the present work, a phase-field model for dendritic solidification is applied to hot-dip ZnAlMg coatings to elucidate the morphology of zinc dendrites and the solute segregation leading to the formation of eutectics. These aspects define the microstructure that conditions the corrosion resistance and the mechanical behaviour of the coating. Along with modelling phase transformation and solute diffusion, the implemented model is partially coupled with the tracking of crystal orientation in solid grains, thus allowing the effects of surface tension anisotropy to be considered in multi-dendrite simulations. For this purpose, the composition of a hot-dip ZnAlMg coating is assimilated to a dilute pseudo-binary system. 1D and 2D simulations of isothermal solidification are performed in a finite element solver by introducing nuclei as initial conditions. The results are qualitatively consistent with existing analytical solutions for growth velocity and concentration profiles, but the spatial domain of the simulations is limited by the required mesh refinement.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.136-140
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• 2009

The verification of irradiation treatments, using dried garlic and cabbage treated at 0-20 kGy, was investigated by analyzing the photostimulated luminescence (PSL), electron spin resonance (ESR) and thermoluminescence (TL) characteristics of the samples. The PSL results showed that the photon counts/60 sec of the non-irradiated dried garlic and cabbage were 287-337, corresponding to negative, while those of the irradiated samples were 7511-54063 photon counts/ 60 sec, corresponding to positive, making it possible to discriminate the non-irradiated from the irradiated samples. In ESR analysis, the dried garlic irradiated at 20 kGy exhibited cellulose radicals, whereas the irradiated dried cabbage showed crystalline sugar-induced multi-component signals, which were not found in the non-irradiated samples. The ESR signal intensity significantly increased as the irradiation dose increase ($R^2$= 0.9369 - 0.9926). The TL glow curves of the irradiated samples appeared at a temperature interval of 150-250, which were significantly different from those of non-irradiated samples, showing a significant increase in TL signal intensity with irradiation dose ($R^2$= 0.9670 - 0.9768). To enhance the reliability of the results, the first glow curve ($TL_1$) was compared with the second glow curve ($TL_2$) obtained after a re-irradiation step at 1 kGy. The TL ratio ($TL_1/TL_2$) was in good agreement with the reported TL threshold values for both the non-irradiated (<0.1) and irradiated (> 0.1) samples.

• Particle and aerosol research
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• v.13 no.1
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• pp.25-31
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• 2017

This paper offer the characteristics for the detection and classification of biological and non-biological aerosol particles in the air by using laser-induced-fluorescence (LIF) based Bio-aerosol Detection System (BDS). The BDS is mainly consist of an optical chamber, in-outlet nozzle system, 405 nm diode laser, an avalanche photo detector (APD) for scattering signal and photomultiplier tubes (PMT) for fluorescence signals in two different wavelength range ; F1, 510-600 nm and F2, 435-470 nm. The detection characteristics, especially ratio of fluorescence signal intensity were examined using well-known components : polystylene latex (PSL), fluorescence PSL, $2{\mu}m$ of SiO2 micro sphere, dried yeast, NADH, ovalbumin, fungicide powder and standard dust. The results indicated that the 405 nm diode laser-based LIF instrument can be a useful bio-aerosol detection system for unexpected biological threaten alter in real-time to apply for dual-use technology in military and civilian fields.

• Communications of the Korean Mathematical Society
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• v.11 no.4
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• pp.1055-1059
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• 1996

We characterize the left invariant Riemannian metrics on SO(1,2) which give rise to 3- or 4-dimensional isometry groups.

• Journal of applied mathematics & informatics
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• v.9 no.2
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• pp.579-591
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• 2002

Let G be a finite group and $\omega$(G) the set of elements orders of G. Denote by h($\omega$(G)) the number of isomorphism classes of finite groups H satisfying $\omega$(G)=$\omega$(H). In this paper, we show that for G=PSL(3, q), h($\omega$(G))=1 where q=11, 12, 19, 23, 25 and 27 and h($\omega$(G)=2 where q = 17 and 29.