• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.341-341
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• 2001

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.31-37
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• 2010

This study was carried out to investigate the thermal decomposition and execute EIDS slow cook-off test for the propellant ingredients and 2 kinds of HTPE propellants. The thermal analysis of the propellant ingredients used in this study showed that the thermal stability of these materials decreases in the following order : AP > HTPE > AN > BuNENA. In addition, propellant HTPE 002 containing AN showed that an endothermic process at around $125^{\circ}C$ corresponding to the solid phase change(II$\rightarrow$I) of AN was followed by the exothermic process of BuNENA/AN mixture up to $200^{\circ}C$. In EIDS slow cook-off tests, HTPE 001 and HTPE 002 reacted at around $250^{\circ}C$ and $152^{\circ}C$ respectively, and both of them showed sudden temperature increase curves at $115^{\circ}C$. The critical temperatures, $T_c$, of thermal explosion for the propellants HTPE 001 and HTPE 002, were obtained from both the non-isothermal curves at various heating rates and Semenov's thermal explosion theory. Kissinger's method that was used to calculate $T_c$ was also employed to obtain the activation energies for thermal decompositions.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.129-135
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• 2007

The critical micelle concentrations (CMC) and the counter ion binding constants (B) in a micellar state of the mixed surfactant systems of Tetradecyltrimethylammonium bromide (TTAB) with Polyoxyethylene(23) lauryl ether (Brij 35) in water were determined as a function of α1 (the overall mole fraction of TTAB) by the use of electric conductivity method and surface tensiometer method from 15 oC to 35 oC. Values of thermodynamic parameters (ΔGom, ΔHom, and ΔSom) for the micellization of TTAB/Brij 35 mixtures were calculated and analyzed from the temperature dependence of CMC values. The results say that the measured values of ΔGom are all negative at the whole measured condition but the values of ΔSom and ΔHom are positive or negative, depending on the measured temperature and α1.

• Journal of the Korean Vacuum Society
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• v.20 no.4
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• pp.307-312
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• 2011

As a technique for removing cancerous tumors from normal tissue, radio-frequency electromagnetic waves were employed to heating target cells up to the critical temperature, which kills the cancerous cells. However, its use in treating tumors in soft organs is limited by inconvenient factors, which are use of high-currents and long time operation. In this work, the feasibility of the localized heating by inserting four conducting electrodes with tiny direct current is investigated. The heat source is resulting from the electric field as known as resistive heating. We have investigated the temperature distribution as a function of applying DC voltages ranging from 10 V to 30 V with 10 V step. From the simulation results, the mushroom-like lesion shape by applying 20 V is generated by four electrodes within a few minutes, that is proper to the clinical application.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.381-383
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• 2006

The hatching rate of the eggs of Nannophya pygmaea Rambur, an endangered dragonfly species in Korea, was experimented in different temperature conditions ($10,\;15,\;20,\;25,\;and\;30^{\circ}C$) in laboratory. N. pygmaea eggs were collected from female adults inhabited a small wetland in Mungyong-si, Kyeongsangbuk-do, Korea, in July 2006. The hatching rate was evaluated from the number of hatched nymphs for the period of 100 days. As a result, the hatching rates were 83, 89, and 76% at $20,\;25,\;and\;30^{\circ}C$, respectively; however, eggs were not hatched at $10^{\circ}C\;and\;15^{\circ}C$ during the experiment period. The derived thermal threshold for egg hatching was $14.3^{\circ}C$, which is relatively higher than the values of other temperate dragonflies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.4
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• pp.414-420
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• 1985

The melting phenomenal of the horizontal cylindrical ice-bar submerged in water are experimentally investigated for the temperature range from 2.5.deg. C to 15.deg. C. The shapes of the melting ice-bar are recorded by the Photo-elasticity Apparatus with modification of the test section. The shadowgraphs of the melting ice-bar show that water adjacent to the bar flows upward for the temperature range from 2.5.deg. C to 5.6.deg. C while above the temperature of 5.6.deg. C the flow is downward direction. The local and average Nusselt numbers become minimum at 5.6.deg. C which is considered as a critical temperature and the Nusselt numbers increase as temperature difference from the critical temperature increase.

• Fire Science and Engineering
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• v.21 no.4
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• pp.25-31
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• 2007

The combustion characteristics and combustion heat of sandwich panel cores were analysed using variable external irradiation level. The characteristics such as ignition time, critical heat flux, ignition temperature and surface temperature profile were measured. Fuel samples were exposed to incident heat fluxes from 15 to $50\;kW/m^2$. For the measurement of various combustion characteristics, the size of specimen was $100\;mm\;{\times}\;100\;mm\;{\times}\;50\;mm$ and the samples were 3 different kinds. As results, Type B showed the best characteristics in measurement of combustion heat and ignition temperature and Type C showd the best characteristics in critical heat flux and surface temperature profile than that of the other two. In conclusion, we knew that Type C had the best performance in fire safety from all data of this study.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.395-408
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• 2013

Environmental condition can induce changes in early life-history traits in order to maximise the ecological fitness. Here I investigated how temperature change and variation in human aquatic activity/behaviour affect early life-history consequences in fish using a dynamic-state-dependent model. In this study, I developed a general fish's life-history model including three life-history states depend-ing on foraging activity, such as body mass, mass of reproductive tissue (i.e., gonadal development) and accumulated stress (i.e., cellular or physiological damage). I assumed the level of foraging activity maximises reproductive success-ultimately, fitness. The model predicts that growth rate, development of reproductive tissues and damage accumulation are greater in higher temperature whereas higher human aquatic activity rapidly reduced the growth rate and development of reproductive tissue and increased damage accumulation. While higher foraging activity in higher temperature is less affected by human aquatic activity, the foraging activity in lower temperature rapidly declined with human aquatic activity. Moreover, lower survival rate in higher temperature or human aquatic activity was independent on mortality rate due to human aquatic activity or mortality rate when foraging activity, respectively. However, the survival rate in lower temperature or human aquatic activity was dependent on these mortality rates. My findings suggest that including of early life-history traits in relation to climate-change and human aquatic activity on the analysis may improve conservation plan and health assessment in aquatic ecosystem.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.35.1-35.1
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• 2009

오스테나이트계 Fe-10Cr-10Ni-xC(x=0.2, 0.5, 0.6and 0.7wt.%)합금에서 변형유기마르텐사이트상변태가 Sliding 마모저항성에 미치는영향을 탄소 및 온도에 따라 조사하였다. 변형유기마르텐사이트상변태가 미치는 영향을 살펴보기 위해 석출물적고 grain의 크기가 비슷한 합금내에서 조사하였다. 변형유기마르텐사이트상변태가 일어나는데 필요한 에너지를 변형률-응력 곡선을 통해 구할 수 있으며, 이를 임계변형에너지라 규명했다. 그 결과, 상온에서 Carbon 함량에 따라 변형유기마르텐사이트상변태가 일어나는데 필요한 임계변형에너지는 증가하였으며, Sliding 마모저항성은 저하되었다. 이는 carbon이 오스테나이트 안정화원소(austenite stabilityelement)이므로 carbon 함량이 증가할수록 변형유기마르텐사이트상변태가 유발하기위해서는 많은 에너지가 필요하기 때문에 low C에 비해 high C의 마모저항성이 저하된 것으로 사료된다. 또한 변형유기마르텐사이트상변태가 고온 Sliding 마모저항성에 미치는 영향을 살펴보기 위해 Fe-Cr-Ni-xC(x=0.2, 0.5, 0.6 and 0.7wt.%)합금을 온도별(25, 100, $300^{\circ}C$)로 조사하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.7
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• pp.775-780
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• 2015

Because of the advantages such as the zero electrical resistance effect that disappears in the vicinity of the absolute temperature and the magnetic levitation effect, the superconducting applications are being tried in a variety of fields. But, those have faced many difficulties in the practical use because of the difficulty for the realization of the superconducting critical temperature. Recently, however, because the high-temperature super conductors was discovered newly which show superconductivity more than $30^{\circ}K$, the application researches based on it are being tried in various fields. Therefore, this paper examines the possibilities and issues by surveying the high temperature superconducting applications to electrical power system.