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Thermoelectric properties in p-type nanostructured Ge-doped Sb100GeTe150 alloy
J.L. Cui,H. Fu,X.L. Liu,D.Y. Chen,W. Yang 한국물리학회 2009 Current Applied Physics Vol.9 No.5
Ge-doped Sb100GeTe150 alloy were prepared using spark plasma sintering technique, and its thermoelectric properties were evaluated over the temperature range 318–492 K. Through XRD analysis, we observed the same single phase as Sb2Te3 and weakened diffraction peaks. Rietveld refinement reveals that there is 0.96 at.% Ge that occupies in the Sb sites, leading to the lattice distortion in the Sb–Te crystal. High-resolution TEM images show that there are many nanodomains randomly distributed in the matrix with a large amount of amorphous phase adjoined. Measurements indicated that the Seebeck coefficients (α) increase and the electrical and thermal conductivities decrease with temperature in the entire temperature range. The maximum α value reaches 135 μV/K at 492 K, and the thermal conductivities are about 0.3 W/mK lower than those of present Sb2Te3 for the corresponding temperatures. The highest thermoelectric figure of merit ZT for the nanostructured alloy Sb100GeTe150 is 0.84 at 492 K, whereas that of the currently prepared Sb2Te3 is 0.74 at the corresponding temperature. Ge-doped Sb100GeTe150 alloy were prepared using spark plasma sintering technique, and its thermoelectric properties were evaluated over the temperature range 318–492 K. Through XRD analysis, we observed the same single phase as Sb2Te3 and weakened diffraction peaks. Rietveld refinement reveals that there is 0.96 at.% Ge that occupies in the Sb sites, leading to the lattice distortion in the Sb–Te crystal. High-resolution TEM images show that there are many nanodomains randomly distributed in the matrix with a large amount of amorphous phase adjoined. Measurements indicated that the Seebeck coefficients (α) increase and the electrical and thermal conductivities decrease with temperature in the entire temperature range. The maximum α value reaches 135 μV/K at 492 K, and the thermal conductivities are about 0.3 W/mK lower than those of present Sb2Te3 for the corresponding temperatures. The highest thermoelectric figure of merit ZT for the nanostructured alloy Sb100GeTe150 is 0.84 at 492 K, whereas that of the currently prepared Sb2Te3 is 0.74 at the corresponding temperature.
A Study on Thermal Analytical Model for a Dry Dual Clutch
Hao Liu(류하오),J. C. Lee(이재천),Y. J. Noh(노유정),J. H. Cho(조종환),H. R. Lee(이희락),J. E. Koh(고재욱),J. W. Kang(강지우) 유공압건설기계학회 2015 드라이브·컨트롤 Vol.12 No.1
The stability of friction characteristics and thermal management for a dry type dual clutch transmission (DCT) are inferior to those of a wet clutch. Too high temperature resulting from frequent engagement of DCT speeds up degradation or serious wear of the pressure plate or burning of the clutch disk lining. Even though it is significantly important to estimate the temperature of a dry double clutch (DDC) in real-time, few meaningful study of the thermal model of DDC has been known yet. This study presented a thermal analytical model of lumped parameters for a DDC by analyzing its each component firstly. Then a series of experimental test was carried out on the test bench with a patented temperature telemetry system to validate the proposed thermal model. The thermal model, whose optimal parameter values were found by optimization algorithm, was also simulated on the experimental test conditions. The simulation results of DDC temperature show consistency with the experiment, which validates the proposed thermal model of DDC.