Electric Power Sources Based on the Seebeck Effect of Manganese Sulfides with Rare Earth Substitution

The thermoelectric properties of compounds with variable valence Mn1-ХReХS (0 ≤ X ≤ 0.2) in the temperature range of (80 – 1100) K are studied. The maxima on the temperature dependences of the Seebeck coefficient (thermal EMF) for all substitution concentrations and the change of the sign of the Seebeck coefficient from positive to negative with an increase in the substitution concentration in Mn1-XYbXS are determined. A model of impurity donor 4f-states is proposed and a satisfactory agreement with the data on the thermal EMF is obtained.

ADAPTATION OF THE METHOD OF CONTROLLING CUTTING MODES TO INDUSTRIAL CONDITIONS

Variants of devices with the possibility of using the test pass method in industrial conditions for automatic determination of cutting modes by measuring the mutual properties of the tool - material contact pair through the value of the thermal EMF that occurs during machining are considered.

Температурные зависимости коэффициента термоэдс, удельного сопротивления и теплопроводности электронного и дырочного пирита FeS-=SUB=-2-=/SUB=- в интервале 293-400 K

The temperature dependences of the thermal EMF, the specific electrical conductivity, and the specific thermal conductivity of samples of natural pyrite FeS2, with electronic and hole-type conductivity, are studied in the temperature range of 293−400 K. The data obtained are in good agreement with the results of previous studies of the electrical properties of this mineral, established in the course of geophysical studies. Based on the results of the performed measurements, as well as taking into account the known data on the temperature behavior of the thermo-EMF and the specific electrical conductivity of pyrite in the range of 300−700 K, estimates of its thermoelectric efficiency are mad

Parameters of Charge Carrier Traps in ZnSe

Taking zinc selenide (ZnSe) crystals as an example, a procedure of determination of the main parameters of traps is proposed. At first, the conductivity type (electron or hole one) in a crystal of phosphor at its excitation is determined with the help of photoelectric studies or studies of the thermionic emission or thermal or photo-thermal emf. Then the energy of the thermal electron delocalization is determined, e.g., by using the method of thermally stimulated luminescence with sequential fractional heating. As a result, the frequency factors of corresponding traps are found as well. Knowing the effective electron mass, it is easy to calculate the effective density of electron states in the conduction band. Finally, the cross sections of the free-electron localization and their temperature dependences can be determined for all traps from a simple equation.