Yu. I. Shtern

Heat capacity of the n-Bi2Te2.88Se0.12 and p-Bi0.52Sb1.48Te3 solid solutions

The heat capacity of the n-Bi2Te2.88Se0.12 and p-Bi0.52Sb1.48Te3 solid solutions has been measured from 360 to 600 K. The data, represented in the form Cp = a + bT + cT−2, have been used to evaluate the thermodynamic functions of the solid solutions in the range 298.15 to 600 K.

Current state of thermoelectric material science and the search for new effective materials

The reasons for the recent increased interest in thermoelectricity are considered. Modern thermoelectric materials for practical use are reviewed. Criteria to be met by effective thermoelectric materials are analyzed. It is shown that the solid-solution method has almost completely exhausted itself. Directions in the search for new thermoelectric material classes are analyzed. The development of new bulk thermoelectric materials is connected with the search for and design of materials in which the peculiarities of the structure determine the strong scattering of phonons and decrease in thermal conductivity while maintaining high transport properties of charge carriers. The concept ‘phonon glass–electron crystal’ is of practical interest. Scientific and technological advances over the last decade give hope that more effective thermoelectric materials will be developed in the nearest future. One of the perspective applications of new thermoelectric materials is connected with the development of thermoelectric generators with segmented thermoelectric elements.

Mathematical models and hardware & software for highly accurate electronic temperature meters

Optimal mathematical models accurately describing the dependence of thermometric parameters of sensors within the range of operational temperatures were suggested. Circuit and design concepts, and also algorithms and hardware & software implementing the developed mathematical models in electronic temperature-measuring instruments were developed.

Prospects of creating efficient thermoelectric materials based on the achievements of nanotechnology

The elaboration of low-dimensional thermoelectric structures has been shown to allow an increase in the efficiency of thermoelectric materials by the end of the 20th century. The achievements in nanotechnology open up new opportunities in searching for prospective thermoelectric materials and structures. The physical aspects in the creation of low-dimensional thermoelectric structures have been reviewed. The capabilities of developing technologies for the synthesis of thermoelectric structures on the basis of superlattices, quantum wires, and quantum dots have been analyzed. The methods of fabrication and advances in the elaboration of nanocomposite thermoelectric materials have been discussed. The problems in the production of second-generation nanocomposites and their possible solutions have been considered. The methods for diagnosing low-dimensional thermoelectric structures are presented, as well.

Investigation of thermal linear expansion for nanostructured Si0.8Ge0.2P0.022 in wide temperature range

The results of investigation of thermal linear expansion for high temperature thermoelectric material nanostructured Si0.8Ge0.2P0.022 n-type with maximum thermoelectric figure of merit Z = 0.98 10-3 K are presented. Investigations were carried out by dilatometric method in the temperature range from 300 to 1220 K in dynamic heating and cooling regimes with using of infrared radiation source. Temperature dependence of thermal linear expansion coefficient (TLEC) was analyzed. The average value of TLEC for Si0.8Ge0.2P0.022 was determined, which is equal to ~5.910-6 K-1.

Mo/Ni and Ni/Ta–W–N/Ni thin-film contact layers for (Bi,Sb)2Te3-based intermediate-temperature thermoelectric elements

We have examined the possibility of utilizing thin-film contact layers for producing reliable Ohmic contacts to proposed intermediate-temperature (Bi,Sb)2Te3-based thermoelectric materials with improved thermoelectric properties, which allow the working temperature range to be extended to 600 K. Three contact configurations have been produced by ion-plasma magnetron sputtering: a single Ni layer, Mo/Ni bilayer, and Ni/Ta–W–N/Ni three-layer system. It has been shown that reliable contacts can be produced using Mo/Ni and Ni/Ta–W–N/Ni layers, which prevent interdiffusion between the materials to be joined and ensure good adhesion to the thermoelectric element.

Thermoelectric systems for maintaining thermal conditions of computing machinery

Different variants of design solutions for thermoelectric systems (TESs) with various cooling powers used to maintain thermal conditions of computing machinery are proposed. Techniques for the calculation of thermoelectric blocks, confirmed by the results of investigations of the fabricated TES units, were developed.

Electronic thermometer with the data transfer by radiochannel

Precise electronic thermometer (ET) with the data transfer by radio channel is developed. Original patented design, circuitry and program solutions are employed in ET. Measuring hardware-software complexes for the investigation and calibration of ET are developed on the basis of the National Instruments equipment with using of LabView software.

Hardware and software equipment for the complex investigation of the wireless smart transducers

Hardware and software equipment for the complex investigation of the wireless smart transducers used in the systems for controlling thermodynamic parameters of energy carries was developed on the basis of National Instruments equipment. Stand tests and qualify transducers by the parameters of radio channel and power supply simulating real conditions of exploitation. Software on the development environment of LabView is developed for automation of investigation and testing processes. Stand can be operatively rearranged by appropriate adjustments, which allows testing following wireless standards: ZigBee, WiFi, WiMAX, Bluetooth, etc.

Intelligent system and electron components for controlling individual heat consumption

An intelligent system and its electron components are developed that implement an innovative method for measuring individual heat consumption. For the intelligent system and its electron components, original design-technological, circuit, hardware, and software solutions are proposed. The methods and mathematical models for evaluating individual heat consumption are developed and validated.