Effect of Annealing on Thermoelectric Properties of Crystals YbxBi2-xTe3
Famil Imran Mamedov,
Seyyara Adil Nabieva,
Sevinj Zellabdin Melikova,
Gunel Talat Imanova
Issue:
Volume 8, Issue 1, March 2023
Pages:
1-5
Received:
2 December 2022
Accepted:
21 December 2022
Published:
4 March 2023
Abstract: The work is devoted to the study of the thermoelectric properties of solid crystal YbxBi2-xTe3. In the work presents the results of studies of the thermoelectric properties of YbxBi2-xTe3 (х≤0.10) solid solutions before and after annealing in the temperature range (300-580)K. Regularities of changes in the electrical conductivity, Seebeck coefficient and total thermal conductivity of the samples depending on the content of ytterbium (Yb) are established. Dependences of electrical conductivity, Seebeck coefficient, thermal conductivity on temperature for the crystal under study are plotted. Temperature curves were recorded using a Termoscan-2 low-frequency temperature recorder at a heating rate of 283 K/ min. Temperature measurements of phase transformations were carried out with combined chromel-alumel thermocouples. Studies of conductivity σ, thermoelectric power (S). were carried out by the four-probe method at direct current in the temperature range of 300-600 K. Ohmic contacts were applied using alloys. It has been established that the optimal combination of these thermoelectric characteristics is achieved for the compositions x = 0.1, which are characterized by the maximum thermoelectric index (ZT=0.87) of the figure of merit in the temperature range of 420-500 K after annealing at 500 K for τ=240 hours. It was revealed that the YbxBi2-xTe3 systems under study are n-type semiconductor thermoelectric materials in the temperature range of 300-600K.
Abstract: The work is devoted to the study of the thermoelectric properties of solid crystal YbxBi2-xTe3. In the work presents the results of studies of the thermoelectric properties of YbxBi2-xTe3 (х≤0.10) solid solutions before and after annealing in the temperature range (300-580)K. Regularities of changes in the electrical conductivity, Seebeck coefficie...
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Simulation Mobile Phone Radiation of Dipole Antenna Using HFSS
Khitam Elwasife,
Heba Aboamra,
Mohammad Shabat
Issue:
Volume 8, Issue 1, March 2023
Pages:
6-12
Received:
1 June 2023
Accepted:
19 June 2023
Published:
27 June 2023
Abstract: The use of information and communication technology is growing throughout society and world, A new products and solutions are developed at an increasing rate. Also half-wave dipole is the most common antenna in recent year, This antenna is used in all transmitters that are broadcast in all directions the parallel to the surface of the ground or in the receptors that pick up signals from all directions this work designed a new half wave dipole antenna and planar dipole antenna using the high-frequency structural simulator (HFSS software is used for the simulation and design calculations of the dipole antennas. The half wave length dipole antenna supposed as wire antenna operating at 900 MHz and 1800 MHz can be modeled in HFSS as two cylinders separated by a small gap. The proposed antenna consists of a two cylinder radiating with a rectangular lumped port excitation between each arm of dipole to provide an radio frequency excitation to antenna element. The model is then covered by a vacuum box to permit radiation of fields, radiating boundary condition will be exercised to outer surface to work as infinite free space. Further the faces of the vacuum box are individually separate and distinct selected for assigning the radiation boundary. After the simulation the measured and simulated characteristics of the antenna are shown and drawn which used a numerical and experimental results regarding the radiation characteristics are presented and discussed. The return loss, VSWR, Directivity, gain, radiation pattern are evaluated. The figure illustrated the aims of this work, Also this model shows the comparison of smith chart for input impedance and polar plot for input impedance for the proposed antennas.
Abstract: The use of information and communication technology is growing throughout society and world, A new products and solutions are developed at an increasing rate. Also half-wave dipole is the most common antenna in recent year, This antenna is used in all transmitters that are broadcast in all directions the parallel to the surface of the ground or in ...
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