• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1725-1732
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• 2002

Combined convection and radiation heat transfer in a circular tube with circumferential fins and circular disks is investigated for various operating conditions. Using a finite volume technique for steady laminar flow, the governing equations are solved in order to study the flow and temperature fields. The P- 1 approximation and the weighted sum of gray gases model (WSGGM) are used for solving the radiation transport equation. The results show that the total Nusselt number of combined convection and radiation is higher than that of pure convection. If the temperatures of the combustion gas and the wall in a tube are high, radiation becomes dominant. Therefore, it is necessary to evaluate the effect of radiation on the total heat transfer.

• Journal of Radiation Industry
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• v.5 no.4
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• pp.353-357
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• 2011

Degradation of p-nitrophenol has been carried out using only gamma irradiation or gamma irradiation with $H_2O_2$ or $Na_2S_2O_8$. Effects of different operating parameters such as initial concentration ($50mg\;l^{-1}$, $100mg\;l^{-1}$, $200mg\;l^{-1}$, $300mg\;l^{-1}$, $400mg\;l^{-1}$, $500mg\;l^{-1}$ and $600mg\;l^{-1}$) on the extent of degradation has been investigated. At 5 kGy, $50mg\;l^{-1}$ p-nitrophenol was completely degraded, and the radiolytic degradation of p-nitrophenol was described by the pseudo-first-order kinetic model. The combination of gamma irradiation with $H_2O_2$ or $Na_2S_2O_8$ leads to an enhanced effect, which remarkably increased the degradation efficiency of p-nitrophenol and TOC removal. However, at high $H_2O_2$ concentration, the efficacy of p-nitrophenol degradation is reduced because ${\cdot}OH$ radicals are scavenged by $H_2O_2$ and $Na_2S_2O_8$.

• Bulletin of the Korean Mathematical Society
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• v.57 no.4
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• pp.921-932
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• 2020

In this paper we prove the local existence of strong solutions to an isentropic compressible Navier-Stokes-P1 approximate model arising in radiation hydrodynamics in a bounded domain with vacuum.

• Physical Therapy Korea
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• v.9 no.3
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• pp.1-9
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• 2002

The purpose of this study was to compare the experimental pain threshold when used in luminous lamp radiation and nonluminous lamp radiation with healthy person. Thirty normal subjects were randomly assigned two groups: a luminous lamp radiation group, and a nonluminous lamp radiation group. The infrared lamps were applied on L3 for thirty minutes. Each group was measured for experimental pain threshold and local temperature before, 15 and 30 minute radiation. For statistical differences in change of the experimental pain threshold and local temperature due to differences in lamp ray was compared using the independent t-test. And, General linear model for profile plots test was used. The results were as: 1. Local temperature was significantly increased in the nonluminous lamp group (p<.01). 2. Experimental pain thershold was significantly increased in the luminous lamp group (p<.05),(p<.01). This study indicate that luminous lamp radiation was more effects of increase experimental pain thershold than nonluminous lamp radiation. Further study is needed to compare the effects of after period radiation.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1321-1335
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• 2022

This study was conducted to investigate the effect of absorption coefficient models on the P1 radiation model for a premixed hydrogen flame containing the water vapor. A CFD combustion simulation analysis was performed using XiFoam, one of the open-source CFD solvers in OpenFOAM. The solver using the flamelet combustion model has been modified to implement radiative heat transfer. The absorption coefficient models used in this study the grey-mean model and constant model, and for comparison, case without radiation was added. This CFD simulation study consisted of benchmarking the THAI HD-15 and HD-22 experiments. The difference between the two tests is the inclusion of water vapor in the condition before ignition. In the case of the HD-22 experiment containing water vapor in the initial condition, the simulation results show that the grey-mean absorption coefficient model has a strong influence on the temperature decrease of the flame and on the change in pressure inside the vessel.

• Journal of Korean Academy of Nursing
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• v.53 no.2
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• pp.222-235
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• 2023

Purpose: The aim of this study was to identify the factors explaining protective behaviors against radiation exposure in perioperative nurses based on the theory of planned behavior. Methods: This was a cross-sectional study. A total of 229 perioperative nurses participated between October 3 and October 20, 2021. Data were analyzed using SPSS/WIN 23.0 and AMOS 23.0 software. The three exogenous variables (attitude toward radiation protective behaviors, subjective norm, and perceived behavioral control) and two endogenous variables (radiation protective intention and radiation protective behaviors) were surveyed. Results: The hypothetical model fit the data (χ²/df = 1.18, SRMR = .02, TLI = .98, CFI = .99, RMSEA = .03). Radiation protective intention (β = .24, p = .001) and attitude toward radiation protective behaviors (β = .32, p = .002) had direct effects on radiation protective behaviors. Subjective norm (β = .43, p = .002) and perceived behavior control (β = .24, p = .003) had direct effects on radiation protective intention, which explained 38.0% of the variance. Subjective norm (β = .10, p = .001) and perceived behavior control (β = .06, p = .002) had indirect effects via radiation protective intention on radiation protective behaviors. Attitude toward radiation protective behaviors, subjective norm, and perceived behavioral control were the significant factors explaining 49.0% of the variance in radiation protective behaviors. Conclusion: This study shows that the theory of planned behavior can be used to effectively predict radiation protective behaviors in perioperative nurses. Radiation safety guidelines or education programs to enhance perioperative nurses' protective behaviors should focus on radiation protective intention, attitude toward radiation protective behaviors, subjective norm, and perceived behavioral control.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.677-682
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• 2014

Resveratrol has been examined in several model systems for potential effects against cancer. Adenosine monophosphate-activated protein kinase (AMPK) is reported to suppress proliferation in most eukaryocyte cells. Whether resveratrol via AMPK inhibits proliferation of oesophageal adenocarcinoma cells (OAC) is unknown. The aim of this study was to determine the roles of AMPK in the protective effects of resveratrol in OAC proliferation and to elucidate the underlying mechanisms. Treatment of cultured OAC derived from human subjects or cell lines with resveratrol resulted in decreased cell proliferation. Further, inhibition of AMPK by pharmacological reagent or genetical approach abolished resveratrol-suppressed OAC proliferation, reduced the level of $p27^{Kip1}$, a cyclin-dependent kinase inhibitor, and increased the levels of S-phase kinase-associated protein 2 (Skp2) of $p27^{Kip1}$-E3 ubiquitin ligase and 26S proteasome activity reduced by resveratrol. Furthermore, gene silencing of $p27^{Kip1}$ reversed resveratrol-suppressed OAC proliferation. In conclusion, these findings indicate that resveratrol inhibits Skp2-mediated ubiquitylation and 26S proteasome-dependent degradation of $p27^{Kip1}$ via AMPK activation to suppress OAC proliferation.

• Journal of Radiation Protection and Research
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• v.36 no.1
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• pp.1-7
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• 2011

A simple mathematical model of simultaneous combined action of environmental agents has been proposed to describe the synergistic interaction of microwave and high ambient temperature treatment on animal heating. The model suggests that the synergism is caused by the additional effective damage arising from an interaction of sublesions induced by each agent. These sublesions are considered to be ineffective if each agent is taken individually. The additional damage results in a higher body temperature increment when compared with that expected for an independent action of each agent. The model was adjusted to describe the synergistic interaction, to determine its greatest value and the condition under which it can be achieved. The prediction of the model was shown to be consistent with experimental data on rabbit heating. The model appears to be appropriate and the conclusions are valid.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4013-4021
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• 2022

A kind of zirconium phosphate mesoporous coordination polymer Zr-EDTMPA was successfully synthesized and characterized using XRD, FTIR, TGA, EA, SEM-EDS, and N₂ sorption-desorption measurements. The prepared Zr-EDTMPA was first employed for the removal of Co(II) from an aqueous solution, and the effects of pH, contact time, temperature, initial Co(II) concentration, reusability, and sorption mechanism were systematically investigated. The results showed that the Zr-EDTMPA is a zirconium phosphate complex formed by the coordination of EDTMPA to Zr in a molar ratio of 1:1. The sorption of Co(II) by Zr-EDTMPA was a pH-dependent, spontaneous and endothermic process, which was better fitted to the pseudo-second-order kinetic model and Langmuir isotherm model. The Zr-EDTMPA was demonstrated to have excellent reusability and presented a high sorption capacity of 73.0 mg·g^-1 for Co(II) at pH 8.0. The sorption mechanism was mainly attributed to the strong coordination between cobalt and the untapped hydroxyl functional groups on Zr-EDTMPA, which was confirmed by XPS spectra. Therefore, as a candidate sorbent with high sorption capacity and excellent reusability, Zr-EDTMPA has a great potential for the removal of Co(II) from aqueous solutions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.4
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• pp.667-680
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• 1995

튜브 내의 입구영역에서 난류 유동에 의한 대류와 비회복사(non-gray radiation)가 동시에 일어날 때의 열전달특성을 수치해석적으로 연구하였다. 작동유체는 이산화탄소, 수증기, 질소의 혼합가스라고 가정하였다. 지배방정식을 계산하기 위해 유한차분법이 이용되었고, 복사전달방정식을 이차편미분방정식으로 바꾸기 위해 P-1 근사법이 사용되었다. 그리고 혼합가스의 비회흡수계수(non-gray absorption coefficient)는 지수광폭밴드모형(exponential wide band model)을 이용해서 구하였다. 열전달특성에 대한 온도조건의 영향을 조사하기 위해 튜브의 축방향에 대한 평균 온도와 뉴셀트수(Nusselt number)의 변화를 몇 가지 다른 온도조건에 대해 나타내었다. 또한, 가스의 성분조성에 대한 영향을 조사하였으며, 이러한 결과에 기초해서 튜브 내에서 난류유동에 의한 대류와 비화복사가 동시에 일어날 때의 복사 뉴셀트수를 쉽게 예측할 수 있는 방법을 제시하였다.