Absolute measurements of the thermal conductivity of mixtures of alcohols with water

1989 ◽  
Vol 10 (4) ◽  
pp. 793-803 ◽  
Author(s):  
M. J. Assael ◽  
E. Charitidou ◽  
W. A. Wakeham
Keyword(s):  
Thermal Conductivity ◽  
Absolute Measurements

High Spatial Resolution Thermal Conductivity investigation of SiC Wafers

2001 ◽  
Vol 680 ◽  
Author(s):  
D.I. Florescu ◽  
Fred H. Pollak ◽  
G.R. Brande ◽  
B.E. Landini ◽  
A.D. Salant
Keyword(s):  
Thermal Conductivity ◽  
High Power ◽  
Defect Density ◽  
Depth Resolution ◽  
Scanning Thermal Microscopy ◽  
Roughness Effects ◽  
Semiconductor Electronics ◽  
Device Applications ◽  
Absolute Measurements ◽  
Spatial Depth

ABSTRACTSilicon carbide (SiC) is a material with very attractive properties for high power/high temperature electronic devices. Its mechanical strength, high thermal conductivity ( κ), large bandgap, and extreme chemical inertness are a few of the characteristics making SiC interesting for semiconductor electronics. Due to the significant head load generated over large areas in high power devices, it is desirable forthe thermal properties of the substrate to be uniform and optimal. Scanning thermal microscopy (SThM), which provides nondestructive, absolute measurements of the thermal conductivity with a spatial/depth resolution in the 2-3 μm range, was used to examine the room temperature κ as a function of position of four 2” diameter SiC wafers. Wafers of 4H and 6H polytype were fabricated with carrier concentrations in the(1-3)×1018 cm−3 and (6-9)×1017 cm−3 ranges, respectively. A radial distribution of the thermal conductivity was determined for all the investigated samples. For a radius r < r1 (r1 ∼ 0.3”) and r > r2 (r2 ∼ 0.7”) highest thermal conductivity values were measured in the range of (3.8-3.9) W/cm-K, comparable to the highest κ reported for this material [D. Morelli et al., Inst. Phys. Conf. Ser. 137, 313 (1993); E.A. Burgemeister,.et al., J. Appl. Phys. 50, 5790 (1979)]. For r1 < r < r2 the thermal conductivity drops to about (2.85-3.25) W/cm-κinterval. Atomic force microscopy (AFM) investigation revealsthat the influence of surface roughness effects on κ is negligible. The κ dip may arise from a higher basal plane defect density in this region that could be associated with the presence of super screw dislocations, or “micropipes” [M. Dudley et al., J. Phys. D: Appl. Phys. 28, A63 (1995)]. The implications of these findings for device applications and design are considered.

Absolute measurements of the thermal conductivity of mixtures of alkene-glycols with water

1989 ◽  
Vol 10 (6) ◽  
pp. 1127-1140 ◽  
Author(s):  
M. J. Assael ◽  
E. Charitidou ◽  
S. Avgoustiniatos ◽  
W. A. Wakeham
Keyword(s):  
Thermal Conductivity ◽  
Absolute Measurements

Pulse-Decay Method for Measuring the Thermal Conductivity of Living Tissues

1981 ◽  
Vol 103 (4) ◽  
pp. 253-260 ◽  
Author(s):  
M. M. Chen ◽  
K. R. Holmes ◽  
V. Rupinskas
Keyword(s):  
Thermal Conductivity ◽  
Measurement Time ◽  
Present Communication ◽  
Single Measurement ◽  
Probe Volume ◽  
Sampling Volume ◽  
Absolute Measurements ◽  
Living Tissues ◽  
Microprobe Technique

The present communication presents a single microprobe technique for measuring tissue thermal properties based on the dissipation of a measured amount of energy and the observation of the resulting temperature rise a given time later. An advantage of this method is that the effective sampling volume can be varied by varying the measurement time. Using a measurement time of a few seconds, the sampling volume was estimated to be several orders of magnitude greater than the probe volume. Hence artifacts due to probe-induced trauma or stress would be insignificant. Additional advantages of the technique are: the results were independent of the probe shape, size and properties, and hence represents absolute measurements without the need for calibration; the required electronics and computations are simple; the determination of thermal conductivity requires only a single measurement; and comparison of data at different measurement times yields a clear and unequivocal indication of nonconductive contributions of heat transfer, if present.

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