Thermal expansion coefficient. See

Thermal-expansion coefficient See coefficient of thermal expansion. 

Thermal-Expansion Coefficient See Coefficient of Thermal Expansion. 

Since the glass transition corresponds to a constant value of the relaxation time [15], dTjdP is just the pressure coefficient of Tg. Comparing Equations 24.10 and 24.13, we see that the scaling exponent is related to quantities—thermal pressure coefficient, thermal expansion coefficient, Tg, and its pressure coefficient—that can all be determined from PVT measurements... 

Joule appears to have assumed dL/dT)p,f/L to be zero for/=0. Given above in parentheses in column three is the value of the linear thermal expansion coefficient on the basis of which initial values in parentheses in other columns replace those given by Joule (see table on p. 106 of Ref. 4). 

This value is comparable with the thermal expansion coefficients of other solvents (see Table II). 

The measure of the thermal expansion coefficient below room temperature is particularly difficult for low-expansion materials (see Section 3.9). Remember also how newly produced composite materials show extremely low-expansion coefficient of both sign. 

With increasing T and constant P, olivines expand their octahedral sites Ml and M2, whereas the tetrahedral group [8104] remains virtually unaffected. Table 5.9 lists linear thermal expansion coefficients for Ml-O and M2-0 polyhedra in some olivine compounds, according to Lager and Meagher (1978). These values are generally higher than those obtained by the method of Hazen and Prewitt (1977) (see eq. 1.93 and section 1.14.2). In particular, thermal expansion is anom-... 

The cathode materials used have to conduct both oxide ions and electrons satisfactorily, but, in addition, for compatibility, they must have similar thermal expansion coefficients as the electrolyte. The strontium-doped perovskite, LSM (see Section 5.4.2), is one of the materials of choice. 

The linear thermal expansion coefficient p calculated from these measurements are in excellent agreement with literature data obtained by the conventional method. For example, the values of P calculated from the thermal effects Q during stretching of PS and PET films agree well with conventional dilatometric results, i.e. for PS PQ = 6.8xKT5 -1, PdU = 7.0x 10-5 K 1 for PET PQ = 5.4x 10 5 K-1, Pdu = 5 0 x 10"5 K 1. The characteristic heat to work ratio q depends hyper-bolically on strain which is also in an excellent agreement with prediction following from the thermomechanical analysis (see Fig. 1). 

Table 1.1. Abundance of the metal in the earths s crust, optical band gap Es (d direct i indirect) [23,24], crystal structure and lattice parameters a and c [23,24], density, thermal conductivity k, thermal expansion coefficient at room temperature a [25-27], piezoelectric stress ea, e3i, eis and strain d33, dn, dig coefficients [28], electromechanical coupling factors IC33, ksi, fcis [29], static e(0) and optical e(oo) dielectric constants [23,30,31] (see also Sect. 3.3, Table 3.3), melting temperature of the compound Tm and of the metal Tm(metal), temperature Tvp at which the metal has a vapor pressure of 10 3 Pa, heat of formation AH per formula unit [32] of zinc oxide in comparison to other TCOs and to silicon...

Thermal expansion of a semiconductor depends on its microstructure, i.e. stoichiometry, presence of extended defects, ffee-carrier concentration. For GaAs [24] it was shown that for samples of free-electron concentrations of about 1019 cm"3, the thermal expansion coefficient (TEC) is bigger by about 10% with respect to the semi-insulating samples. Different microstructures of samples examined in various laboratories result in a large scatter of published data even for such well known semiconductors as GaP or GaAs. For group III nitrides, compounds which have been much less examined, the situation is most probably similar, and therefore the TECs shown below should not be treated as universal values for all kinds of nitride samples. It is especially important for interpretation of thermal strains (see Datareview A 1.2) for heteroepitaxial GaN layers on sapphire and SiC. 

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