• Food Science of Animal Resources
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• v.29 no.3
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• pp.325-333
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• 2009

Beef quality indicators of off-flavor development during storage were investigated in terms of temperature dependence. The off-flavor development time (ODT) was detected using the R-index sensory test. During varying storage conditions at $25^{\circ}C$, $15^{\circ}C$, and $5^{\circ}C$, elements of beef quality were measured, such as volatile basic nitrogen (VBN), pH, color (CIE $L^*$, $a^*$, $b^*$), Warner-Bratzler shear force (WBSF), Pseudomonas spp. CFU, and lactic acid bacteria (LAB) CFU. A model with temperature dependence of ODT during storage was developed using Arrhenius-like equation, and a requirement with quality indicators was mathematically derived, resulting in similar temperature dependence. The temperature dependence of beef quality indicators was represented by the Arrhenius activation energy (Ea). Upon comparing the Ea of beef quality indicators and ODT, the temperature dependence similarity was found to be higher in the order of three groups: VBN, pH, $a^*$ value; LAB, Pseudomonas spp.; and WBSF, $L^*$ value, $b^*$ value. Therefore, VBN were determined as the most effective indicator of beef quality during off-flavor development.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.50-58
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• 1993

The ignition delay of diesel oil and fish oil blended with diesel oils was investigated at various pressure and temperature conditions in a constant volume combustion bomb. The evaporation and combustion duration of diesel oil and fish oil blended with diesel oils were respectively different in high and low temperature. The dependence of ignition delay on the temperature was different in high and low temperature ranges which were divided at the 773K. The dependence of ignition delay on the pressure was almost linear, regardless of the test fuels at the constant temperature(863K). The ignition delay became longer as the blending rate of fish oil increased at the constant temperature and pressure, but it was especially short with 20% fish oil blended with diesel oils.

• Journal of the Korean Vacuum Society
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• v.8 no.4A
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• pp.450-455
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• 1999

We present Photoluminescence (PL) and Atomic Force Microscopy (AFM) image on InAs quantum dots (QDs) having different size which grown by Molecualr Beam Epitaxy (MBE). For different size QDs, analysis of the AFM profiles show that the density of QDs was the maximum value $(1.1\times10^{11}\textrm{/cm}^2)$ at 2.0 ML. In the spectra of QDs, it is found that the peak energy decreases with increasing dot size due to the effect of quantum confinement. Temperature dependence of PL intensities show that the PL is quenching and Red shift as the temperature increase. The FWHM range of 20K~180K is narrowing with increasing temperature. When temperature is over 180K, the line-width starts to in creases with increasing temperature. At last, temperature dependence of the integrated intensities were fit using the Arrehenius-type function for the activation energy. Fit value of the activation energy was increased with increasing QDs-size.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.380-382
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• 1989

Dielectric breakdown strength (Eb) of thin Poly(Vinylidene Fluoride ; PVDF) film is studied in the temperature range between 4.2 K and 400 K. The results of this study can be summerized as follows. 1) Temperature dependence of dielectric breakdown strength (Eb) can be devided into high and low temperature regions. The critical temperature (Tc) at which two regions are devided depends on applied voltage. 2) Dielectric breakdown strength (Eb) by pulse voltage is higher than that by DC voltage. Especially this difference is remarkable at low temperature.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.393-398
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• 1999

The temperature dependence of the viscosity was determined for an electrorheological(ER) fluid consisting of 35 weight% zeolite particles in hydraulic oil 46cSt. Thermal activation analysis were performed by changing the ER fluid's temperature from -1$0^{\circ}C$ to 5$0^{\circ}C$ at fixed electric field. According to the analysis, the activation energy for flow was about 79.64kJ/mole at E=0kV/mm. Generally, the hydraulic oil 46cSt will be operated at the temperature of about 4$0^{\circ}C$, the ER fluid's electric field dependence of viscosities were investigated at this temperature. also, the influence of adding the dispersant(Carbopl 940) on electrorheological effect of the ER fluid was discussed.

• Journal of the Society of Disaster Information
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• v.2 no.1
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• pp.129-137
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• 2006

The present work is attempt to evaluate the temperature dependence of blast furnace slag concrete(BFSC) based on the concrete strength cured with different curing temperatures and ages. A equivalent substitution index(ESI) was induced to explain temperature dependence of concrete quantitatively as well as concrete strength. The results from compressive strength showed substantial crossover effect. which is the phenomenon that the compressive strength cured at low temperature becomes stronger than the one cured at high temperature. The crossover effect found more definitely on BFSC than plain concrete.. The ESI became 1.1 and 1.0 for the BFSC cured at $20^{\circ}C$ and $30^{\circ}C$ after age of 56 days, respectively. Which means that the contribution to strength development of blast furnace slag per unit mass is stronger than that of the Portland cement. It was considered therefore that the optimum curing temperature for BFSC is $20^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.29-32
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• 2000

In this paper, an analytical model for I-V characteristics of a HEMTs is Proposed. The developed model takes into account the temperature dependence of drain current. In high-speed ICs for optical communication systems and mobile communication systems, temperature variation affects performance; for example the gain, efficiency in analog circuits and the delay time, power consumption and noise mrgin in digital circuits. To design such a circuit taking into account the temperature dependence of the current-voltage characteristic is indispensible. This model based on the analytical relation between surface carrier density and Fermi potential including temperature dependent coefficients.

• Journal of Magnetics
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• v.18 no.3
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• pp.221-224
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• 2013

Electron paramagnetic resonance (EPR) spectra of $Mn^{2+}$ impurity ion in Stoichiometric $LiNbO_3$ single crystal (SLN) was investigated with an X-band EPR spectrometer in the temperature range of 3 K~296 K. The intensity of EPR spectrum of $Mn^{2+}$ ion was increased to 20 K and decreased again below 20 K as the temperature decreases. The zero-field splitting parameter D decreased as the temperature increases. It was suggested that $Mn^{2+}$ ion substitute for $Nb^{5+}$ ion instead of $Li^+$ ion. No changes for hyperfine interaction of $Mn^{2+}$ ion was obtained in the temperature range of 3 K~296 K.

• Korean Journal of Materials Research
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• v.10 no.5
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• pp.335-342
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• 2000

The microhardness of rhenium sheets was determined as a function of indentation load and temperature. The temperature dependence of the microhardness between room temperatures and $1000 ^{\circ}C$was studied using a hot microhardness tester equipped with a Vickers indenter. The load dependence of the microhardness was investigated using oth a Vickers and a Knoop indenter. The indentation size effect (ISE) was well explained using the normalized Meyers law. The hardness of the annealed rhenium sheet approached that of the as-rolled sheets at large indentation loads because of work-hardening under the indenter during indentation. The hardness at zero load(obtained from extrapolation of the load dependence of the hardness) suggested that the hardness is controlled by two different mech-anisms having different thermal activation. At low temperature the activation energy for the mechanism controlling the hardness was approximately 0.02 eV , Whereas at higher temperatures that was approximately 0.15eV. The tranisi-tion temperature between the two different controlling mechanisms was about $250^{\circ}C$.

• Journal of the Korean Society of Safety
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• v.9 no.4
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• pp.29-41
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• 1994

High temperature tensiles tests, steady state creep tests, internal stress tests and creep rupture tests using Al 7075 alloy were performed over the temperature range of 9$0^{\circ}C$~50$0^{\circ}C$ and stress range of 0.64~17.2(kgf/$\textrm{mm}^2$) in order to investigate the creep behavior and predict creep rupture life From the apparent activation energy Qc and the applied stress exponent n measured, at the temperature range of 9$0^{\circ}C$~l2$0^{\circ}C$, the creep deformation seemed to be controlled by cross slip. On the other hand at the temperature of 20$0^{\circ}C$~23$0^{\circ}C$ the creep deformation seemed to be controlled by dislocation climb but at 47$0^{\circ}C$~50$0^{\circ}C$, by diffusion creep. And the rupture life(t$_{f}$) might be represented by anthermal process attributed to the difference of the applied stress dependence of Internal stress and the ratio of the Internal stress to the applied stress, the thermal activated process attributied to the temperature dependence of the internal stress. Also the ratio between stress dependence of primary creep rate and that of minimum creep rate was measured 0.46, the minimum creep rate is expected to be appromately obtained from master creep curve including the relationship primary creep rate and minumum creep rate. Finally the relationship new rupture parameter and logarithmic stress was represented with including the ratio between the dependence of primary creep rate and that of minimum creep rate, using the new rupture parameter the rupture life predition is exactly expected.d.