• Journal of radiological science and technology
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• v.24 no.1
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• pp.61-65
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• 2001

This study was conducted to find out gamma dose rate in Seoul, from January to December in 2000, and the following results were achieved ; 1. The annual gamma dose rate in Seoul was $17.24{\mu}R/hr$ as average. 2. The annual gamma dose rate in subway of Seoul was $14.96{\mu}R/hr$ as average. 3. The highest annual gamma dose rate was Dong-daemon ku. 4. Annual gamma dose rate in Seoul was higher autumn than winter.

• Nuclear Engineering and Technology
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• v.7 no.3
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• pp.223-226
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• 1975

The relative detection efficiency of ${\gamma}$-ray full-energy Peaks was obtained by a pair-point method using the $^{56}$ Co source whose ${\gamma}$-ray relative emission rates were well measured. Three Ge(Li) detectors with active volumes of 43.8cc, 32.6cc, and 6cc were calibrated over the ${\gamma}$-ray energy energy range 800-5, 500keV.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.4
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• pp.28-32
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• 2009

This paper compares two speech estimators under a generalized Gamma distribution for DFT-based single-microphone speech enhancement methods. For the speech enhancement, the noise estimation based on recursive averaging spectral values by spectral minimum noise is applied to two speech estimators based on the generalized Gamma distribution using $\kappa$=1 or $\kappa$=2. The performance of two speech enhancement algorithms is measured by recognition accuracy of automatic speech recognition(ASR) in car noisy environment.

• Fibers and Polymers
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• v.5 no.3
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• pp.225-229
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• 2004

The effect of UV and $^60{Co}$ gamma radiations on the physical and mechanical properties of nylon 6 mono-filaments with different draw ratios has been studied. Specimens were exposed to either up to 25 Mrad of gamma or up to 168 hrs of intense UV irradiation. The results show that nylon mono-filaments exposed to gamma rays, with much higher quantum energy than UV, undergo a larger extent of molecular chain scission. Higher irradiation dose also results in the production of insoluble, macroscopic three-dimensional cross-linked network structure. The amorphous regions with a lower density of cohesive energy (lower molecular orientation) show a higher extent of cross linking reaction whereas amorphous regions with a higher density of cohesive energy (higher orientation) show higher extent of chain scission reaction, irrespective of UV ray or gamma ray irradiation.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.565-573
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• 2004

This study is to present explicit analytical expressions for calculating bearing capacity factor $N_{\gamma}$, to provide results of the numerical computation instead of the graphical method. In this study, $N_{\gamma}$ is proposed in the critical failure surface on assumption that the center of log spiral in the radial shear zone can be located at the any points of around footing. The critical failure surface is one which yields minimum passive pressure $P_{\gamma}$ on the radial shear zone from the family of log spirals accoding to change of the center of log spiral. This study adoptes Terzaghi's bearing capacity principle(e.g., Prandtl's mechanism, limit equilibrium equation, superposition principle) but the soil wedge in an elastic zone makes angle $45^{\circ}+{\phi}/2$ with the horizontal and the location of the log spiral's center.

• Journal of applied mathematics & informatics
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• v.36 no.3_4
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• pp.213-229
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• 2018

In this work, we establish oscillation of the second order sublinear neutral delay dynamic equations of the form:$$(r(t)((x(t)+p(t)x({\tau}(t)))^{\Delta})^{\gamma})^{\Delta}+q(t)x^{\gamma}({\alpha}(t))+v(t)x^{\gamma}({\eta}(t))=0$$ on a time scale T by means of Riccati transformation technique, under the assumptions $${\displaystyle\smashmargin{2}{\int\nolimits^{\infty}}_{t_0}}\({\frac{1}{r(t)}}\)^{\frac{1}{\gamma}}{\Delta}t={\infty}$$, and ${\displaystyle\smashmargin{2}{\int\nolimits^{\infty}}_{t_0}}\({\frac{1}{r(t)}}\)^{\frac{1}{\gamma}}{\Delta}t$ < ${\infty}$, for various ranges of p(t), where 0 < ${\gamma}{\leq}1$ is a quotient of odd positive integers.

• Honam Mathematical Journal
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• v.35 no.1
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• pp.101-107
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• 2013

The Gamma function ${\Gamma}$ which was first introduced b Euler in 1730 has played a very important role in many branches of mathematics, especially, in the theory of special functions, and has been introduced in most of calculus textbooks. In this note, our major aim is to explain the convergence of the Euler's Gamma function expressed as an improper integral by using some elementary properties and a fundamental axiom holding on the set of real numbers $\mathbb{R}$, in a detailed and instructive manner. A brief history and origin of the Gamma function is also considered.

• Journal of the Korean Mathematical Society
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• v.48 no.3
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• pp.655-667
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• 2011

A class of functions involving divided differences of the psi and tri-gamma functions and originating from Kershaw's double inequality are proved to be completely monotonic. As applications of these results, the monotonicity and convexity of a function involving the ratio of two gamma functions and originating from the establishment of the best upper and lower bounds in Kershaw's double inequality are derived, two sharp double inequalities involving ratios of double factorials are recovered, the probability integral or error function is estimated, a double inequality for ratio of the volumes of the unit balls in $\mathbb{R}^{n-1}$ and $\mathbb{R}^n$ respectively is deduced, and a symmetrical upper and lower bounds for the gamma function in terms of the psi function is generalized.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.465-467
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• 1997

The comparative effects of ozone treatment and gamma irradiation on the sterilization, physicochemical properties and sensory quality of red pepper powder were investigated. As for the sterilization of microorganisms, 7.5~10 KGy of gamma irradiation completely eliminated the coliforms, yeast and molds, and total aerobic bacteria. On the other hand, ozone treatment failed to eliminate the highly contaminated microbial load, especially total aerobic bacteria. The physicochemical properties including capsaicin, capsanthin, browning, fatty acid compositions and sensory quality were not significantly changed by gamma irradiation up to 10 kGy, whereas ozone treatment caused significant changes in fatty acid compositions and destruction of natural pigments (p<0.05). The above results led us to conclude that gamma irradiation was more effective than ozone treatment for the sterilization and maintenance of physicochemical and sensory qualities of red pepper powders.

• Journal of the Korean Chemical Society
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• v.15 no.5
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• pp.241-245
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• 1971

Endothermic peak of transformation of ${\gamma}-MnO_2$ was obviously shown by differential heating curve in the present study, and the transformation temperature was different from other modification. ${\gamma}-MnO_2$ carried out to analyze exclusively, by means of the half area method in corresponding endothermic peak of differential heating curve. ${\alpha}-\;and\;{$beta}-MnO_2$ (Pyrolusite) containing in sample about 75% is interfered about ${\pm}$10% of the relative error, and while those of below 50% is interfered about ${\pm}$5%.