• 한국재료학회지
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• 제24권11호
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• pp.625-631
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• 2014

To investigate the deformation properties of TiC-(5-20) mol% Mo solid solution single crystals at high temperature by compression testing, single crystals of various compositions were grown by the radio frequency floating zone technique and were deformed by compression at temperature from 1250K to 2270K at strain rates from $5.1{\times}10^{-5}$ to $5.9{\times}10^{-3}/s$. The plastic flow property of solid solution single crystals was found to be clearly different among a three-temperature range (low, intermediate and high temperature ranges) whose boundaries were dependent on the strain rate. From the observed property, we conclude that the deformation in the low temperature range is controlled by the Peierls mechanism, in the intermediate temperature range by the dynamic strain aging and in the high temperature range by the solute atmosphere dragging mechanism. The work softening tends to become less evident with an increasing experimental temperature and with a decreasing strain rate. The temperature and strain rate dependence of the critical resolved shear stress is the strongest in the high temperature range. The curves are divided into three parts with different slopes by a transition temperature. The critical resolved shear stress (${\tau}_{0.2}$) at the high temperature range showed that Mo content dependence of ${\tau}_{0.2}$ with temperature and the dependence is very marked at lower temperature. In the higher temperature range, ${\tau}_{0.2}$ increases monotonously with an increasing Mo content.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.264-268
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• 2001

In this study, CT specimens were prepared from spring steel(SUP9) processed shot peening which was room temperature, low temperature and high temperature experiment. And we got the following characteristics from fatigue crack growth test carried out in the environment of room, and high temperature at $25^{\circ}C,\; 50^{\circ}C, \;100^{\circ}C,\; 150^{\circ}C,\; and\; 180^{\circ}C$ in the range of stress ratio of 0.05 by means of opening mode displacement. The threshold stress intensity factor range $\DeltaK_{th}$ in the early stage of fatigue crack growth (Region I ) and stress intensity factor range $\Delta$K in the stable of fatigue crack growth (Region II) was decreased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature and high temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.1022-1025
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• 2001

This paper presents the characteristics of TaN thin-film as high-temperature strain gauges, which were deposited on Si substrate by DC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(4∼20%)N$_2$). The electrical and mechanical characteristics of these films investigated with the thickness range 1650∼1870${\AA}$ and room temperature resistivities in the range 178.3 ${\mu}$$\Omega$cm to 3175.7 ${\mu}$$\Omega$cm. The TaN thin-film strain gauge deposited in Ar-(20%)N$_2$atmosphere is obtained a temperature coefficient of resistance(TCR), 0∼-1357 ppm/$^{\circ}C$ in the temperature range 25∼275$^{\circ}C$ and a high temporal stability with a longitudinal gauge factor, 2.92∼3.47. Because of their high resistivity, low TCR and linear gauge factor, these cermet thin-film may allow high-temperature strain gauges miniaturization.

• Journal of Welding and Joining
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• 제14권1호
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• pp.38-46
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• 1996

High temperature low cycle fatigue crack growth behavior is investigated over a range of two temperatures and various frequencies in SUS 304 stainless steel. It is found that low frequency and temperature can enhance time-dependent crack growth. With high temperature, low frequency and long crack length, ${\Delta}J_c/{\Delta}J_ f$, the ratio of creep J integral range to fatigue J integral range is increased and time-dependent crack growth is accelerated. Interaction between ${\Delta}J_f$ and ${\Delta}J_c$ is occured at high frequency and low temparature and ${\Delta}J_c$, creep J integral range is fracture mechanical parameter on transition from cycle-dependent to time dependent crack growth in creep temperature region.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.42-50
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• 2001

An experimental study has been carried on high-preheated temperature air combustion. Because the flames with high-preheated temperature air combustion were much more stable and homogeneous(both temporally and spatially) as compared to the room-temperature combustion air. The global flame feature showed range of flame colors (yellow, blue, blurish-green) over the range of conditions. Low level of NOx along with low level of CO have been obtained under high-preheated air combustion conditions. The thermal and chemical behavior of high-preheated air combustion flames depends on preheated temperature and oxygen concentration air.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2001년도 추계학술대회 논문집(Proceeding of the KOSME 2001 Autumn Annual Meeting)
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• pp.65-70
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• 2001

In this study, CT specimens were prepared from spring steel(SUP9) processed shot peening which was room temperature, low temperature and high temperature experiment. And we got the following characteristics from fatigue crack growth test carried out in the environment of room, low temperature and high temperature at $25^{\circ}C$, -3$0^{\circ}C$, -5$0^{\circ}C$, -7$0^{\circ}C$, -10$0^{\circ}C$ and 5$0^{\circ}C$, 10$0^{\circ}C$ , 15$0^{\circ}C$, 18$0^{\circ}C$ and in the range of stress ratio of 0.05 by means of opening mode displacement. The threshold stress intensity factor range $\DeltaK_{th}$ in the early stage of fatigue crack growth (Region I ) and stress intensity factor range ΔK in the stable of fatigue crack growth (Region II) was decreased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature and high temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1757-1760
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• 2007

Moving a droplet by electrowetting is the basis of our novel displays. This enables mechanical bistable and high reflective monochrome as well as color systems. Since no high temperature process is required, plastic substrates can be used. Our prototypes show promising performance in terms of a wide temperature range, contrast ratio and color.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.101-103
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• 2012

Characteristic of aluminum ignition under high temperature and high pressure is studied using lasers. The laser ablation method is used to generate aluminum particles exposed to a high pressure by using a nanosecond pulsed laser where the range of ablation pressure varies between 0.35 and 2.2 GPa. A $CO_2$ laser is used to supply radiative heat to the aluminum target surface for providing high temperature ranging between 5000~9300 Kelvin. The ignition is confirmed using spectroscopy analysis of AlO vibronic band 484 nm wavelength. Also the radiative temperature is measured in various high pressure range for tracing the ignition temperature in high pressure conditions.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.167-172
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• 2002

In this study, CT specimens were prepared from spring steel(SUP9) processed shot peening which was room temperature, high temperature experiment. And ire got the following characteristics from fatigue crack growth test carried out in the environment of room, and high temperature at $25^{\circ}C,\;100^{\circ}C,\;150^{\circ}C$ and $180^{\circ}C$ in the range of stress ratio of 0.3 by means of opening mode displacement. The threshold stress intensity factor range ${\Delta}Kth$ in the early stage of fatigue crack growth (Region I) and stress intensity (actor range ${\Delta}K$ in the stable of fatigue crack growth (Region II) was decreased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at high temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region.

• 대한기계학회논문집A
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• 제27권7호
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• pp.1152-1158
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• 2003

The mechanical behavior of a commercially pure titanium (CP-Ti) is investigated at high temperature Split Hopkinson Pressure Bar (SHPB) compression test with high strain-rate. Tests are performed over a temperature range from room temperature to 1000$^{\circ}C$ with interval of 200$^{\circ}C$ and a strain-rate range of 1900 ∼ 2000/sec. The true flow stress-true strain relations depending on temperature are achieved in these tests. For construction of constitutive equation from the true flow stress-true strain relation, parameters for the Johnson-Cook constitutive equation is determined. And the modified Johnson-Cook equation is used for investigation of behavior of flow stress in vicinity of recrystalization temperature. The Modified Johnson-Cook constitutive equation is more suitable in expressing the dynamic behavior of a CP-Ti at high temperature, i.e. about recrystalization temperature.