• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1486-1494
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• 2020

To evaluate transport-induced cladding embrittlement after interim-dry storage, ring compression tests were carried out at room temperature(RT) and 135 ℃. The ring compression test specimens were prepared by simulating the interim-dry storage conditions that include four peak cladding temperatures of 250, 300, 350 and 400 ℃, two tensile hoop stresses of 80 and 100 MPa, two hydrogen contents of 250 and 500 wt.ppm-H and a cooling rate of 0.3 ℃/min. Radial hydride fractions of the ring specimens vary depending on those interim-dry storage conditions. The RT compression tests generated lower offset strains than the 135 ℃ ones. In addition, the RT and 135 ℃ compression tests indicate that a higher peak cladding temperature, a higher tensile hoop stress and the lower hydrogen content generated a lower offset strain. Based on the embrittlement criterion of 2.0% offset strain, an allowable peak temperature during the interim-dry storage may be proposed to be less than 350 ℃ under the tensile hoop stress of 80 MPa at the terminal cool-down temperature of 135 ℃.

• 한국진공학회지
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• 제10권2호
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• pp.247-251
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• 2001

실리콘산화막에 $Si^+$이온을 주입하여 열처리를 한 후 상온에서 8K까지 온도를 변화시키며 PL을 측정하였다. 상온에서 50~80K까지는 PL intensity가 전체적으로 증가하였으며 50K 이하에서는 감소하였다. PL intensity가 증가하는 동안 peaks는 blue-shift가 일어났다. PL spectrum에서 peak를 보이는 파장에서 PL의 온도의존성을 측정하였다. 첫 번째 peak가 온도변화에 가장 민감하며 크기가 작은 peak일수록 온도의 영향을 적게 받는다. PL peak의 온도의존성을 분석하였다. 상온에서 50K 범위에서 PL intensity 대 1000/T그림에서 온도역수의 3차 함수로 fitting할 수 있었다. 온도가 내려갈수록 PL intensity가 증가하는 것을 nanocrystal 보다도 O위주 결함(Si-O-O)이나 Si위주 결함(Si-Si-O)들의 quantum size effect로 설명할 수 있었다.

• Journal of Acupuncture Research
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• 제25권2호
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• pp.129-138
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• 2008

Objectives : The moxibustion is the method in using the heat stimulation made of attached and burned a moxa or other herbal materials on a healing point or acupuncture point and the chemical stimulation of a resin made from burning them. We need to standardize the characteristics of moxa combustion in order to get more systematic and objective result in operation mechanism and effects and then get more clinical abilities in these fields. Methods : In this study, using of labview system on the moxibustion. 1. we studied relation the size of barley and jujube seed with the moxa cone's peak combustion temperature and then measured and compared the moxa cone's peak combustion temperature by tonification and sedation method. 2. we measured the peak combustion temperature of indirect moxibustion. Results & comclusions : 1. When we measured a direct moxibustion's combustion temperature, the jujube seed sized moxa cone's peak temperature was higher than the barley sized moxa cone's when it burned and the time to peak temperature of the barley sized moxa cone was shorter than the jujube seed sized moxa cone's. 2. When the direct moxibustion was burned by the tonification and sedation method, the sedation method's peak temperature was higher than the tonification method's, the tonification's time to peak temperature was shorter than the sedation method's. 3. When we measured the temperature of the moxa combustion in the kinds of sliced herbal materials, the peak temperature of indirect moxibustion with a ginger when it sliced a 1.3mm size and a 1.5mm size was degreed within $40^{\circ}C$ to $52^{\circ}C$ and the peak temperature of indirect moxibustion with a garlic when it sliced a 1.7mm size was degreed within $46^{\circ}C$ to $62^{\circ}C$.

• 한국건축시공학회지
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• 제8권4호
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• pp.115-121
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• 2008

The present study performed low-pressure steam curing with mortar specimens in order to examine the temperature profile and strength development of steam curing in high-strength specimens of 100MPa. In addition, as a basic research to utilize PC products, we examined the effects of curing temperature and time in steam curing cycle on strength development resulting from the hydration of cement within the range of high strength by changing four factors affecting the quality of PC displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature - in various patterns, and analyzed the optimal strength development characteristic based on the relation between temperature profile and strength development. With regard to the high-temperature curing characteristic of PC, we performed an experiment on the strength characteristic according to the temperature profile of high-strength mortar, and from the results of the experiment according to curing characteristic, displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature, we drew conclusions as follows.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.550-557
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• 1997

Production of so-called Halon fire extinguishing agents has been prohibited since January 1994 because of their ozone depletion potential, To replace them, several hydrofluorocarbons and fluorocarbons have been developed and utilized. A number of studies on flame extinguishing concentrations and flammability peak concentrations of them have been done. Although there was enough information for practical purpose, more knowledge on fire extinguishing characteristics of them should be attained for efficient use of them. In this study, peak concentrations of methane/air mixtures with gaseous halogenated hydrocarbons were measured at elevated temperature, because the former studies were done at room temperature and temperature of a fire room can be higher than usual. Measurement was done at $200^{\circ}C$, because measuring system could not endure higher temperature. This study revealed that peak concentrations of halogenated hydrocarbons differed little at elevated temperature. The halogenated hydrocarbons have almost the same fire extinguishing ability as Halon 1301.

• 한국세라믹학회지
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• 제48권3호
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• pp.205-210
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• 2011

The dependence of sulfur redox behavior and its diffusivity on temperature and composition was studied in mixed alkali silicate melts by means of square wave voltammetry (SWV) at different frequencies in a temperature range of $1000^{\circ}C$ to $1400^{\circ}C$. The voltammograms showed two reduction peaks at high frequency but only one peak at low frequency. Irrespective of $K_2O/(Na_2O+K_2O)$, each peak potential due to reduction of $S^{6+}$ to $S^{4+}$ and $S^{4+}$ to $S^0$ moved toward a negative direction with temperature decrease, and the peak current showed a strong dependence on frequency at a constant temperature. However, the compositional dependence of the peak potential showed an inconsistent behavior with an increase of $K_2O$. The mixed alkali effect was not observed in sulfur diffusion. This inconsistency of both peak potential and diffusion for compositional dependence may be derived from the strong volatilization of sulfur in melts.

• 대한전기학회논문지
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• 제34권4호
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• pp.144-152
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• 1985

This paper temperature gradient thermally stimulated surface potentian (TG-TSSP) in measurements are applied to the study of the polarity of trapped and ionic carriers in cross-linked polyethylene (XLPE) filsm. In the thermally stimulated current in uniform temperature (TSC) of XLPE five peaks appear as indicated of the A B C D and E. In this paper A (at about -120$^{\circ}C$) D (at about 70$^{\circ}C$) and E (at about 110$^{\circ}C$) peaks are investigated. A peak is due to the biassing voltage and biassing temperature. Appear in to the glass transition temperature territory and caused in to the polarization of dipole. D peak is due to the depolarization of ionic space charge and E peak due to the detrapping of carriers injected from the electrodes. TG-TSSP and TSSP are measured to study the polarity of ionic carrier (D peak). In the unsatureated region of ionic space charge polarization, TG-TSSP is lower than TSSP during the initial stage of heating. Result of the experiment for E peak, TG-TSSP is higher than TSSP during the initial stage of heating and these results do not depend on the polarity of biassing voltage, and E peak is concerned with positive carriers (Holes).

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1740-1747
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• 2017

To investigate allowable peak cladding temperature and hoop stress for maintenance of cladding integrity during interim-dry storage and subsequent transport, zirconium alloy cladding tubes were hydrogen-charged to generate 250 ppm and 500 ppm hydrogen contents, simulating spent nuclear fuel degradation. The hydrogen-charged specimens were heated to four peak temperatures of $250^{\circ}C$, $300^{\circ}C$, $350^{\circ}C$, and $400^{\circ}C$, and then cooled to room temperature at cooling rates of $0.3^{\circ}C/min$ under three tensile hoop stresses of 80 MPa, 100 MPa, and 120 MPa. The cool-down specimens showed that high peak heat-up temperature led to lower hydrogen content and that larger tensile hoop stress generated larger radial hydride fraction and consequently lower plastic elongation. Based on these out-of-pile cladding tube test results only, it may be said that peak cladding temperature should be limited to a level < $250^{\circ}C$, regardless of the cladding hoop stress, to ensure cladding integrity during interim-dry storage and subsequent transport.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.80-84
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• 1993

In this research, we studied the variation of the dielectric loss absorption of the dielectric loss absorption of the sample according with the change to $\^$60/Co-${\gamma}$-ray irradiation dose of the influence of temperature and applied voltage. In order to investigate the effect of irradiation oriented polypropylene film, we have observed dissipation factor within the temperature range of 30∼130 [$^{\circ}C$] and voltage range of 100∼250$^{\circ}C$ [V]. As for the dependency of temperature by dissipation factor, the ${\alpha}$-peak which appears at high temperature increases accordingly to the increasement of irradiation dose which is contributed by the crystal region and moves towards the high temperature. The ${\beta}$-peak which appears at low temperature is origined from dipoles and molecular motions in the amorphous region. As for the dependency of voltage by tan$\delta$, at low temperature the peak of the tan$\delta$, at low temperature the peak of the tan$\delta$ shifts accordingly to the increasement of irradiation dose towards the high temperature region.

• 대한치과보철학회지
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• 제44권6호
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• pp.690-698
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• 2006

Statement of problems. The heat produced during polymerization of polymer-based provisional materials may cause thermal damage to the vital pulp. Purpose. This study was performed to evaluate the exotherm reaction of the polymerbased provisional materials during polymerization by differential scanning calorimetry and to compare the temperature changes of different types of resins. Material and methods. Three dimethacrylate-based materials (Protemp 3 Garant, Luxatemp Plus, Luxatemp Fluorescence) and five monomethacrylate- based material (Snap, Alike, Unifast TRAD, Duralay, Jet) were selected. Temperature changes of polymer-based provisional materials during polymerization in this study were evaluated by D.S.C Q-1000 (TA Instrument, Wilmington, DE, USA). The following three measurements were determined from the temperature versus time plot: (1) peak temperature, (2) time to reach peak temperature, (3) heat capacity. The data were statistically analyzed using one-way ANOVA and multiple comparison Bonferroni test at the significance level of 0.05. Results. The mean peak temperature was $39.5^{\circ}C({\pm}\;1.0)$. The peak temperature of the polymer-based provisional materials decreased in the following order: Duralay > Unifast TRAD, Alike > Jet > Luxatemp Plus, Protemp 3 Garant, Snap, Luxatemp Fluorescence. The mean time to reach peak temperature was 95.95 sec $({\pm}\;64.0)$. The mean time to reach peak temperature of the polymer-based provisional materials decreased in the following order: Snap, Jet > Duralay > Alike > Unifast TRAD > Luxatemp Plus, Protemp 3 Garant, Luxatemp Fluorescence. The mean heat capacity was 287.2 J/g $({\pm}\;107.68)$. The heat capacity of the polymer-based provisional materials decreased in the following order: Duralay > TRAD, Jet, Alike > Snap, Luxatemp Fluorescence, Protemp 3 Garant, Luxatemp Plus. Conclusion. The heat capacity of materials, determined by D.S.C., is a factor in determining the thermal insulating properties of restorative materials. The peak temperature of PMMA was significantly higher than others (PEMA, dimethacrylate). No significant differences were found among PEMA (Snap) and dimethacrylate (P >0.05). The time to reach peak temperature was greatest with PEMA, followed by PMMA and dimethacrylate. The heat capacity of PMMA was significantly higher than others (PEMA, dimethacrylate). No significant differences were found among PEMA and dimethacrylate (P >0.05).