• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.292-295
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• 2002

In this work, transient characteristics of NPT(Non Punch Through)-IGBT(Insulated Gate Bipolar Transistor) have been studied with different temperatures analytically. Power losses are caused by heat generated in MIT-IGBT for steady state and transient state conditions. We therefore have focused on the analysis of excess carrier concentration and excess charge injected into N-drift layer with different temperatures and have obtained anode voltage drop during turn-off with lifetime of 2.4[${\mu}$s].

• Elastomers and Composites
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• v.39 no.4
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• pp.286-293
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• 2004

Ester- and ether-based thermoplastic polyurethanes of different hardness were injection molded at different mold temperatures and effects of mold temperature on the physical properties of TPUs were investigated. Glass transition temperatures of soft segments of TPUs were hardly changed by mold temperatures. The phase separation of soft and hard segments of injection molded TPUs were affected little by mold temperatures. However, crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength of injection molded TPUs decreased with increasing mold temperatures for TPUs of high hardness. However, injection molded TPUs of low hardness showed increases of crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength with increasing mold temperatures. Different physical properties of injection molded TPUs depending on mold temperatures were attributed to different crystallization and physical crosslinking effects of hard segments.

• International Journal of Concrete Structures and Materials
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• v.10 no.1
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• pp.75-85
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• 2016

Fire ranks high among the potential risks faced by most buildings and structures. A full understanding of temperature effects on fiber reinforced concrete is still lacking. This investigation focuses on the study of the residual compressive strength, stress strain behavior and surface cracking of structural polypropylene fiber-reinforced concrete subjected to temperatures up to $300^{\circ}C$. A total of 48 cubes was cast with different fiber dosages and tested under compression after exposing to different temperatures. Concrete cubes with varying macro (structural) fiber dosages were exposed to different temperatures and tested to observe the stress-strain behavior. Digital image correlation, an advanced non-contacting method was used for measuring the strain. Trends in the relative residual strengths with respect to different fiber dosages indicate an improvement up to 15 % in the ultimate compressive strengths at all exposure temperatures. The stress-strain curves show an improvement in post peak behavior with increasing fiber dosage at all exposure temperatures considered in this study.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.6 no.1
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• pp.1-7
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• 2010

In this paper, an experimental study on the cooling operation characteristics for different entering water temperatures in geothermal heat pump system are carried out by using Lab VIEW system program Set-point temperature controls for cooling water and supply air temperatures is applied to analyze the energy consumption and control performances. As a result, the system responses show that different entering water temperatures(EWT) effect greatly on the energy consumption and system COP.

• Computers and Concrete
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• v.5 no.2
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• pp.89-100
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• 2008

This research examines the engineering properties and color intensities of mortar containing different amounts of fly ash (0, 5, 10 and 20%) mixed at different water-to-binder ratios (w/b = 0.23, 0.47 and 0.59) and exposed at different temperatures (T = 25, 100, 200, 400, 600 and $800^{\circ}C$). Results show that there is greater mass loss on ignition with high w/b and higher temperatures. In addition, the color channel image analyzer (Windows software written in Delphi) is utilized to study the relationship between the curing temperature and intensity of three primary colors, red, green and blue (RGB), of the fly ash mortar specimens. The results show that the RGB intensities on the specimen surface increases from that at $25^{\circ}C$. The mortar specimen becomes white with increase in w/b but without the addition of fly ash. Moreover, for mortar specimens with greater content of fly ash, red on the specimen surface has the greatest increase in intensity at elevated temperature. Observation the variations in color on the specimen surface may help estimate the highest elevated temperatures that concrete structures can withstand.

• Korean Journal of Veterinary Service
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• v.18 no.3
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• pp.1-12
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• 1995

To investigate effect of seeding on post-thaw motility and viability of canine spermatozoa, the semen from male dogs which had been proved to be fertile in the past were frozen and seeded during freezing process. Post-thaw motility and viability of canine sperm which were frozen and seeded were investigated according to different seeding temperatures of $-5^{\circ}C$, $-10^{\circ}C$, or $-l5^{\circ}C$ and also according to different concentration of glycerol of 2%, 5% and 10%. In addition, post-thaw motility of canine sperm frozen by direct freezing in a deep freezer or programmed freezing in a programmed cell freezer was investigated. Post-thaw motility of canine sperm was compared according to different seeding temperatures : The sperm seeded at $-5^{\circ}C$ showed considerably higher post-thaw motility than that of non-seeding, and that seeded at $-10^{\circ}C$, or $-l5^{\circ}C$, respectively, in 2% and 5% glycerol groups on both 2 and 7day after freezing(p<0.05). In 10% concentration of glycerol, the sperm seeded at each seeding temperature showed considerably higher post-thaw motility than that of non-seeding group on day 7 after freezing(p<0.01). Post-thaw viability of canine sperm was compared according to different seeding temperatures : The sperm seeded at $-5^{\circ}$ showed significantly higher post-thaw motility than that of non-seeding, and that seeded at $-10^{\circ}C$, or $-l5^{\circ}C$, in 5% and 10% glycerol groups on day 7 after freezing(p< 0.05). In comparison of post-thaw motility of canine sperm seeded according to different concentration of glycerol, 5% glycerol group and 10% glycerol group showed considerably higher post-thaw motility than 2% glycerol group without difference between those two groups in all seeding temperatures($-5^{\circ}C$, $-10^{\circ}C$ and $-l5^{\circ}C$) on day 2 and 7 after freezing(p<0.01). In comparison of post-thaw viability of canine sperm seeded according to different concentration of glycerol, 5% glycerol group and 10% glycerol group showed the same considerably higher post-thaw viability than 2% glycerol group on each thawing day(p<0.01). The canine sperm frozen and seeded by programmed freezing method showed considerably higher post-thaw motility than that frozen by direct freezing method in all different seeding temperatures($-5^{\circ}C$, $-10^{\circ}C$ and $-l5^{\circ}$). These results indicated that the higher post-thaw motility and viability was obtained in the spermatozoa seeded than that of non-seeding, that among different seeding temperatures of $-5^{\circ}C$, $-10^{\circ}C$ and $-l5^{\circ}C$, the sperm seeded at $-5^{\circ}C$ showed higher post-thaw motility and viability than the other temperatures, also among different concentrations fof glycerol of 2%, 5% and 10%, the sperm frozen and seeded in 5% and 10% concentration of glycerol showed higher post-thaw motility and viability than that in 2% of glycerol, and that the sperm frozen and seeded by programmed freezing method showed higher motility than that by direct freezing method.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.21-24
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• 2002

A sensor array (35mm'! in diaphragm dimension) of 12 sensing elements with different operating temperatures was optimized with respect to thermal operation. This sensor array with single heater on a glass diaphragm over back-etched silicon bulk realizes a novel concept of a sensor array: an way of sensor elements operated at different temperatures can yield more information than single measurement. The proposed micro sensor array could provide well-integrated way structure because it has only single heater at the center of the diaphragm and used the various sensing properties of two kinds of metal oxide layers with various operating temperatures.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.5
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• pp.604-612
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• 2012

The quality characteristics of yackwa made with goami powder at different baking temperatures (150, 160, 170, 180) and baking times (15, 20, 25 min) and at different dipping temperatures (65 and $80^{\circ}C$) and dipping times (15 and 30 min) were evaluated. To determine the optimal temperature and time for yackwa containing goami powder, color values, preference color and pictures were determind. The baking temperatures were $150^{\circ}C$ for 25 min, $160^{\circ}C$ for 15 min and 20 min, and $170^{\circ}C$ for 15 min. The weight of yackwa was heavier at low dipping temperatures and long dipping times. L-values and b-values were the highest at short dipping times. Hardness, moisture and overall preference was the lowest at low dipping temperatures and long dipping times.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.322-325
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• 2002

In this study, noise figures of 0.3 $\mu\textrm{m}$-GaAs MESFETs are predicted experimentally with different temperatures. Both the noise figure and the gate leakage current are obtained with wide range of temperatures(27$^{\circ}C$∼300$^{\circ}C$). From the results, gate leakage current increases with temperatures. It is expected that gate leakage current contributes directly to the increase of shot noise current. It is therefore highly recommended to apply an accurate noise analysis to the design of the devices and modules at high temperatures. Fini,Uy the relation between the gate currents resulting in the increase of noise and the noise figures of submicron GaAs MESFETs are traced with different temperatures

• Advances in materials Research
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• v.8 no.2
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• pp.137-154
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• 2019

In this study, thermal effects on the mechanical properties of cement mortars with some types of fibers is investigated. The replaced fibers were made of polypropylene (PP), aramid, glass and basalt. In other words, the main goal of this paper is to study the effects of different fibers on the mechanical properties of cement mortars after subjecting to normal and sub-elevated temperatures. The experimental tests used for investigating these effects were compressive, splitting tensile, and four-point bending tests at 20, 100 and $300^{\circ}C$, respectively. Moreover, the microstructures of the specimens in different temperatures were investigated using scanning electron microscope (SEM). Based on the experimental results, the negative effects of sub-elevated temperatures on four-point bending tests were much more than the others. Moreover, using the fibers with higher melting points could not improve the qualities of the samples in sub-elevated temperatures.