Репозиторий Университета

© 2020 Elsevier B.V. For thermoelements operating on the Peltier and Seebeck effects, including multisection ones used at temperatures up to 900 K, the physicochemical principles of creating effective thin-film multilayer contact systems obtained by magnetron ion-plasma sputtering have been developed. The formation of contact systems was carried out on thermoelectric materials based on: Bi2Te3; Sb2Te3; PbTe; GeTe with the increased thermoelectric figure of merit. A structure of contact systems consisting of contact layers providing ohmic contact, adhesion, barrier and interconnection properties of contact systems is proposed and justified. The selection criteria for materials of contact layers are substantiated. For multisection thermoelements operating on the Seebeck effect at temperatures above 500 K, the necessity of introducing diffusion-barrier layers into the structure of contact systems providing reliability and invariability of the properties of contact systems is substantiated. Based on the physicochemical analysis, the thermodynamic and kinetic factors of the stability and degradation of diffusion-barrier layers are determined. The influence of methods for preparing the surface of thermoelectric materials on the adhesion, contact resistance, and thermal stability of contact systems is established. Using Auger electron spectroscopy, the analysis of the causes of thermal stability and degradation of contact systems was carried out. The deposition modes were determined. The effective contact systems were obtained and investigated. The respective systems are based on: Ni; Mo/Ni and Ni/(Ta–W–N)/Ni having the adhesive strength of more than 12 MPa; the contact resistance not exceeding 10−9 Ω m2 and thermal stability at temperatures up to 900 K.

© 2020 Elsevier B.V. For thermoelements operating on the Peltier and Seebeck effects, including multisection ones used at temperatures up to 900 K, the physicochemical principles of creating effective thin-film multilayer contact systems obtained by magnetron ion-plasma sputtering have been developed. The formation of contact systems was carried out on thermoelectric materials based on: Bi2Te3; Sb2Te3; PbTe; GeTe with the increased thermoelectric figure of merit. A structure of contact systems consisting of contact layers providing ohmic contact, adhesion, barrier and interconnection properties of contact systems is proposed and justified. The selection criteria for materials of contact layers are substantiated. For multisection thermoelements operating on the Seebeck effect at temperatures above 500 K, the necessity of introducing diffusion-barrier layers into the structure of contact systems providing reliability and invariability of the properties of contact systems is substantiated. Based on the physicochemical analysis, the thermodynamic and kinetic factors of the stability and degradation of diffusion-barrier layers are determined. The influence of methods for preparing the surface of thermoelectric materials on the adhesion, contact resistance, and thermal stability of contact systems is established. Using Auger electron spectroscopy, the analysis of the causes of thermal stability and degradation of contact systems was carried out. The deposition modes were determined. The effective contact systems were obtained and investigated. The respective systems are based on: Ni; Mo/Ni and Ni/(Ta–W–N)/Ni having the adhesive strength of more than 12 MPa; the contact resistance not exceeding 10−9 Ω m2 and thermal stability at temperatures up to 900 K.

© 2018, Allerton Press, Inc. The effect of medium pH and ion strength on the thermal stability of formate dehydrogenases (EC 1.2.1.2, FDH) from model plant Arabidopsis thaliana (AthFDH) and soybean Glycine max (SoyFDH) are studied. The dependence of the residual activity on time is described by the kinetics of the reaction of the first order in all the experimental conditions. The dependence of the first order thermal inactivation constants on phosphate buffer concentration has the form of a bell-shaped curve. It was found that an increase in the pH value resulted in an increase and decrase of inactivation rate constans for SoyFDH and AthFDH, respectively. The activation parameters of the thermal inactivation process, ΔH≠ and ΔS≠ are calculated from the experimental data at different medium pH values and phosphate buffer concentrations.