• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.611-614
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• 2005

In this paper, investigated is the relationship between the formation temperature and the thermal stability of Ni silicide formed with Ni-V (Nickel Vanadium) alloy target. The sheet resistance after the formation of Ni silicide with the Ni-V showed stable characteristic up to RTP temperature of $700\;^{\circ}C$ while degradation of sheet resistance started at that temperature in case of pure-Ni. Moreover, the Ni silicide with Ni-V indicated more thermally stable characteristic after the post-silicidation annealing. It is further found that the thermal robustness of Ni silicide with Ni-V was highly dependent on the formation temperature. With the increased silicidation temperature (around $700\;^{\circ}C$), the more thermally stable Ni silicide was formed than that of low temperature case using the Ni-V.

• Journal of Advanced Marine Engineering and Technology
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• v.6 no.2
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• pp.21-41
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• 1982

Viscosity, especially characteristic among various properties of visco-elastic fluids such as high polymer solutions, is affected mainly by temperature and concentration. Hence, it is important for fluid engineering to express, by some equations, how the fluid characteristics vary with the change of temperature and concentration and to analyze them to obtain consistent viscous characteristics. High polymer solutions, synthetic products of modern chemical industry, suggest many interesting investigations because they are typical visco-elastic materials. Experimentation was made to derive some useful fluid characteristic equations of SEPARAN-NP10 (polyacylamide) expressed by n (flow behavior index) and K' (consistency index) when it is given temperature and concentration variation. To measure viscosity, capillary viscometer was adopted and the range of experimentation is 0-2,000 P.P.M. in concentration and 15-55 .deg.C in temperature. The experimental results are summarized as follows: The flow behavior index n 1) has nearly constant results irrespective of temperature variation at same conentration and the results are shown in (Table. 4-4-3) 2) has following equation, regardless of temperature, for the variation of concentration. n=-1.0765*10$^{-4}$ P+0.9915 (P:P.P.M.) The consistency index K' 1) has different results for the variation of temperature at same concentration and the results are given in (Table.4-7-2) 2) has following equation for the variation of concentration at same temperature. log 10$^{4}$K' =6.4785*10$^{-4}$ P-1.0529 (P:P.P.M)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.85-88
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• 2011

In the trend of world wide environment preservation, researchers tried to find new environment friendly propellant instead of highly toxic propellant, Hydrazine. Among the candidates, ionic liquid propellants have lower toxicity, higher density, and higher specific impulse than Hydrazine. These ionic liquid propellants have high combustion chamber temperature, so catalyst supports such as gamma alumina cannot withstand in that temperature. Therefore, a catalyst that showed stable characteristic in high temperature is needed. Barium dopped alumina can be changed to Hexaaluminate in high temperature, and its characteristic in high temperature is superior than gamma alumina. Barium dopped Alumina is wet impregnated with Platinum and heated up to $1300^{\circ}C$ and $1400^{\circ}C$ for 2 hours. Those catalysts were examined by XRD, SEM, EDS, BET, and Drop test.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.597-599
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• 1996

This paper describes the bending traveling-wave type ultrasonic motor which generates the traveling wave by combining two standing waves with phase difference time and space. In $+20^{\circ}C{\sim}30^{\circ}C$, the USM motor operation character has represented normal condition. But the other temperature, (that is say, when long time operating condition) USM operation characteristic has abnormal condition, that is driving frequency, drive current and r.p.m is down. The recent USM has controller without temperature compensation. This study aimed at fuzzy controller which must follow the frequency at operation temperature and then r.p.m and torque increase.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.52-55
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• 1996

This paper describes the bending traveling-wave type ultrasonic motor which generates the traveling wave by combining two standing waves with phase difference time and space. In $+20^{\circ}C$~$30^{\circ}C$, the USM motor operation character has represented normal condition. But the other temperature, (that is say, when long time operating condition) USM operation characteristic has abnormal condition, that is driving frequency, drive current and r.p.m is down. The recent USM has controller without temperature compensation. This study aimed at fuzzy controller which must follow the phase angle difference 90$^{\circ}$at operation temperature and them r.p.m and torque increase.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.441-444
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• 1997

This paper describes the bending traveling-wave type ultrasonic motor which generates the traveling wave by combining two standing waves with phase difference time and space. In +2$0^{\circ}C$~3$0^{\circ}C$, the operation characteristic of USM has represented normal condition. But in the other temperature, the operation characteristic of USM has abnormal condition, that is driving frequency, drive current and r.p.m are down. The recent USM has controller without temperature compensation. This study aimed at fuzzy controller which must follow the frequency at operation temperature and then r.p.m and torque increased.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.49-54
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• 2006

The evaluation of elastic-plastic fracture characteristic was investigated in ferrite steel SA 516- Gr70 used for reactor coolant piping elbow and support skirt of pressure vessels. This paper describes the effect of temperature on J-R curve characteristic of this material. The elastic-plastic fracture mechanics parameter J is obtained with unloading compliance method. The test method were analyzed according to ASTM E 813-89 and E 1152-89. Unloading compliance $J_{IC}$ tests were performed on 1 CT specimens at varied temperatures from $25^{\circ}C$ to about $400^{\circ}C$ using a high temperature extensometer. At all temperature, valid $J_{IC}$ measurements could be made and $J_{IC}$ decreased with increasing temperature. SEM fractography schematically illustrates microvoid initiation, growth and coalescence at the tip of a preexisting crack.

• Applied Science and Convergence Technology
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• v.24 no.3
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• pp.47-52
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• 2015

The correlation between admittance and dielectric spectroscopy of dielectric relaxation in lead scandium noibate, have been investigated. Lead scandium niobate, with composition $PbSc_{0.5}Nb_{0.5}O_3$, was prepared by conventional solid state synthesis. Conductance Y'(G), susceptance Y"(B) and capacitance C of lead scandium niobate as a function of frequency and temperature were measured. From the temperature-dependence of RLC circuit, insight into physical significance of the dielectric properties of lead scandium niobate is obtained. The relative strong frequency dependent of dielectric properties in lead scandium niobate is observed, and the phase transition occurred at a broad temperature region. Also, the value of critical exponent ${\gamma}$=1.6 showed on heating process. The long relaxation times part enlarged diffuse by conductivity effects with increasing temperature, and the ordering between $Sc^{3+}$ and $Nb^{5+}$ in PSN influences complex admittance and dielectric properties. Confirmed the typical characteristic of lead-type relaxor in the Raman spectra of lead scandium niobate and major ranges are between 400 and $900cm^{-1}$.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.950-951
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• 2015

This paper proposes MPPT control considering temperature characteristic of PV module. Conventional CV(Constant Voltage) and PO(Perturbation and Observation) methods have the weak problem about the insolation and temperature change. Thus, in this paper, in order to improve this problem, the optimal voltage and current is determined and the MPPT control is performed. MPPT algorithm proposed in this paper analyze the performance about insolation and temperature change and proves the validity.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.331-337
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• 2005

This study aims at evaluation of component performance of a commercial micro gas turbine by detailed measurements of various system parameters. A test facility to measure performance of a micro gas turbine was set up. Performance parameters such as turbine exit temperature, exhaust gas temperature, engine inlet temperature, compressor discharge pressure and fuel flow rate were measured. Variations in measured data and estimated performance parameters were analyzed. In addition to overall engine performance, component characteristic parameters including the turbine inlet temperature, the compressor efficiency, the turbine efficiency, the recuperator effectiveness were estimated. Behaviors of the estimated characteristic parameters with operating condition change were examined.