• Elastomers and Composites
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• v.31 no.5
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• pp.335-340
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• 1996

In order to look into the internal structure and the properties in the silicone rubbers added reinforcing fillers; silica $additives(O{\sim}140phr)$, and to examine the behavior of charged particles, the properties of thermally stimulated current(TSC) and X-Ray diffraction are investigated, respectively. And then, from the TSC which are formed by applying the electric field of $2{\sim}5kV/mm$ to specimen at the temperature range from -150 to $260^{\circ}C$, the results are as follwing: In the case of non-filled specimen, four peaks of ${\delta},\;{\gamma},\;{\beta}\;and\;{\alpha}$ are obtained at the temperature of $-120^{\circ}C,\;-60^{\circ}C,\;20^{\circ}C\;and\;130^{\circ}C$, respectively and the case of filled specimen, three peaks of ${\delta},\;{\alpha}_2\;and\;{\alpha}_1$ are observed at the temperature of $-120^{\circ}C,\;80^{\circ}C\;and\;130^{\circ}C$, respectively. The origins of these peaks are that, the ${\delta}$ peak seems to the result from the contribution of side chain methyl radical, and the ${\gamma}$ peak from the depolarization of space charge polarization owing to be added impurity during manufacturing specimens, and the ${\beta}$ peak from the orientation of $Si-CH_3$ dipole, and the ${\alpha}_2$ near the temperature of $80^{\circ}C$ from hydroxyl in carboxylic radical, and finally, the ${\alpha}_1$ peak near the temperature of $130^{\circ}C$ from carboxyl acid that is formed by the thermal oxidation of high temperature.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1349-1352
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• 2009

We report the results of the surface chemistry of deuterized ethanol exposed Zircaloy-4 (Zry-4) surfaces with various amount of $C_2D_5$OD exposures at 190 K. This system was examined with Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) techniques. In TPD study, $D_2$ was evolved at two different desorption temperature regions accompanying with broad desorption background. The lower temperature feature at around 520 K showed first-order desorption kinetics. The high temperature desorption peak at around 650 K shifted to lower desorption temperature as the exposure of $C_2D_5$OD increased. The Zr(MNV) Auger peak shifted about 2.5 eV from 147 eV to lower electron energy followed by 300 L of $C_2D_5$OD dosing. This implies metallic zirconium was oxidized by deuterized ethanol adsorption. After stepwise annealing of the oxidized Zry-4 sample up to 843 K, the shifted Zr(MNV) peak was gradually shifted back to metallic zirconium peak position. After the sample was heated to 843 K, the oxygen content near the Zry-4 surface was recovered to clean surface level. The concentration of carbon, however, was not recovered by annealing the sample.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.345-349
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• 1985

The textural properties of acorn flour gels were investigated with the variations in the concentraction, storage time and storage temperature by the use of Instron Universal Testing Machine. The experimental design was $3^3$ factorial experiment. TPA curves of acorn flour gels showed two sharp peaks in the first bite and no negative peak. The hardness and brittleness of acorn flour gels were very significantly affected by concentration, storage time and storage temperature. For the height difference between first peak and second peals, the main effects for concentration and storage temperature were very significant and the main effect for storage time was not negligible. For bend, the effect of concentration was more significant than the effect of storage temperature, and storage time effect was negligible. Springiness was affected only by the concentration.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.6
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• pp.311-317
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• 2011

The effect of strain rate on the yield stress of an Al-Li alloy has been investigated at temperatures between 77 and 523 K and over the strain rate range from $1.77{\times}10^{-4}s^{-1}$ to $1.77{\times}10^{-2}s^{-1}$. At testing temperatures below 373 K, the yield stress is almost independent of strain rate at any aging stage. At testing temperatures above 373 K, the yield stress increases linearly with the logarithm of strain rate, and the strain rate dependence increases with increasing testing temperature. The yield stresses of under-aged alloy at temperatures between 373 and 473 K at high strain rates are greater than the yield stress at 77 K. For the alloy under-aged or aged nearly to its peak strength, the temperature range within which the positive temperature dependence of yield stress appears expands to the higher temperature side with increasing strain rate. The strain rate dependence of the yield stress is slightly negative at this aging stage. The yield stress of the over-aged alloy decreases monotonically with decreasing strain rate and with increasing testing temperature above 373 K. The modulus normalized yield stress is nearly constant at testing temperatures below 373 K at any strain rate investigated. And, strength depends largely both on the aging conditions and on the testing temperature. The peak positions in strength vs. aging time curves shift to the side of shorter aging time with increasing testing temperature. For the specimens aged nearly to the peak strength, the positive temperature dependence of yield stress is observed in the temperature range. The shift of peak positions in the aging curves are explained in terms of the positive temperature dependence of cutting stress and the negative temperature dependence of by-passing stress.

• Fashion & Textile Research Journal
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• v.19 no.3
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• pp.289-295
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• 2017

This study aims to develop clothing sales forecast system using weather information. As the annual temperature variation affects changes in daily sales of seasonal clothes, sales period can be predicted growth, peak and decline period by changes of temperature. From this perspective, we analyzed the correlation between temperature and sales. Moving average method was applied in order to indicate long-term trend of temperature and sales changes. 7-day moving average temperature at the start/end points of the growth, peak, and decline period of S/S clothing sales was calculated as a reference temperature for sales forecast. According to the 2013 data analysis results, when 7-day moving average temperature value becomes $4^{\circ}C$ or higher, the growth period of S/S clothing sales starts. The peak period of S/S clothing sales starts at $17^{\circ}C$, up to the highest temperature. When temperature drops below $21^{\circ}C$ after the peak temperature, the decline period of S/S clothing sales is over. The reference temperature was applied to 2014 temperature data to forecast sales period. Through comparing the forecasted sales periods with the actual sales data, validity of the sales forecast system has been verified. Finally this study proposes 'clothing sales forecast system using weather information' as the method of clothing sales forecast.

• 전자공학회논문지 IE
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• v.49 no.2
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• pp.40-45
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• 2012

In this paper, cooling system of power transformers is proposed for temperature optimized control. We predict the peak temperature of power transformer coils using load factors and construct a cooling system using weighting function. For the optimized temperature control for power transformer, a correlation function based on the load factor of a load current and the each temperatures for winding coils, for air and for oil is presented to predict the winding-coil peak temperature. Also, the results controlled by applying the power transformer is presented.

• Electrical & Electronic Materials
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• v.11 no.10
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• pp.1-5
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• 1998

Complex dynamic relaxation processes of mechanical as well as dielectric character in polymeric anelastic solids are closely related through the movement of molecular chain segment in morphological structure, and the morphology can easily be modified by the treatments such as mechanical drawing or irradiation, those of which result, in turn, the complicated change on the appearance of the observed complex relaxation peak. In order to extract any meaningful understanding from the modified appearance of the peak, the relaxation peak must be resolved into the sum of the dynamic single relaxation peaks, each of which can be characterized respectively by three factors such as activation energy, magnitude of peak height and peak point temperature on the temperature dependent characteristics.

• Macromolecular Research
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• v.12 no.1
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• pp.141-143
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• 2004

We have investigated the dynamic mechanical behavior of ultra-high molecular weight polyethylene (UHMWPE) irradiated with varying doses of gamma rays. A relaxation peak in the loss factor curve, which has not been reported previously in the literature, is observed at a temperature above the crystal melting temperature. The peak is unique to UHMWPE and appears to be related to the high degree of entanglement. Because the temperature and intensity of the peak are reduced by irradiation-induced chain scission and crosslinking, respectively, we believe that the peak is associated with disentanglement relaxation. The behavior of the storage modulus in the melt state agrees with the classical theory of rubber elasticity.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.497-501
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• 1999

The changes of properties were studied for the polypropylene(PP)/Nylon6 blends containing different kinds of compatibilizer made by either reactive extrusion of solution reaction. The compatibilizers were PP grafted with maleic anhydride (MAH) made by reactive extrusion and solution reaction. The grafted MAH contents were 0.3 wt %, and 2.7 wt %, respectively. The composition of the PP/nylon6 blend was fixed at 75/25 by weight. Blending was carried out with twin-screw extruder (L/D=30, ${\psi}=30$) at 300 rpm. As the content of PP-g-MAH was increased, the crystallization peak of Nylon6 decreased gradually then finally disappeared. Disappearance of crystallization peak of Nylon6 was mostly affected by grafted MAH content rather than the preparation method and the amount of compatibilizer. The portion of Nylon6 that could not crystallize in its normal crystallization temperature crystallized together with PP at the crystallization temperature of PP. So called concurrent crystallization was observed. Meanwhile two more peaks were observed during heating cycle. One was exothermic peak at $193^{\circ}C$ near to crystallization temperature of Nylon6, the other was endothermic peak at $215^{\circ}C$ that was $5^{\circ}C$ lower than normal endothermic peak of Nylon6. To analyze the peaks, nylon6 was annealed in the differential scanning calorimeter. As a result, the peak at $193^{\circ}C$ was crystallization peak of imperfect crystalline of Nylon6 and the other peak at $215^{\circ}C$ was melting peak of imperfect crystalline of nylon6.

• 전기의세계
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• v.30 no.8
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• pp.517-524
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• 1981

Thermally stimulated currents have been obtained from five kinds of polymer electrets. The peak current (I$_{m}$) and the peak temperature (T$_{m}$) of the TSC, particularly at PET thermoelectret, were found to depend on the forming field and the forming temperature. From these experimental results, the TSC spectra can be easily explained by the consideration of the disorientation of dipoles related with glass transition temperature. The obtained results can suggest that the forming field and the forming temperature plays an essential role for charge stability in PET thermoelectrets.ets.