Vahe V. Buniatyan

Microwave characteristics of BARITT diodes based on silicon carbide

Microwave characteristics of barrier-injected (BARITT) diodes made of silicon carbide are investigated. It is shown that the negative resistance of p/sup +/-n-p/sup +/ structure made of different polytypes of SiC is an order of magnitude higher in absolute value in comparison with the Si p/sup +/-n-/sup +/ structure, all other factors being equal, even in the absence of trap levels (TLs). It is shown also that the dynamic negative resistance, in absolute value, the power output and efficiency increase with an increase of the concentration of traps. The effects of TLs in the band gap of the semiconductor on the impedance, power output, and efficiency of SiC BARITT diodes are examined,.

Current State of Biomedical Engineering Education in Armenia and Perspectives of Development with TEMPUS IV BME-ENA Project

Biomedical Engineering (BME) is a modern and dynamic specialty that is predicted to grow over the next decades, partly due to increasing penetration of technological processes and devices into the healthcare system and medical practice, education and research. BME education is regarded as an important tool to support development of healthcare systems and medical industry. BME education in Armenia has been present at certain higher education institutions (HEIs) for some period of time, however the existing study programs need to be updated according to modern standards and practices, and the capacity of the institutions delivering the program needs to be expanded. The 3-year curriculum development project ”Biomedical Engineering Education Tempus Initiative in Eastern Neighboring Area” (BME-ENA) financed through the EU’s Tempus IV funding instrument, involves 17 institutions from 11 EU and ENA countries and is aimed primarily at development and implementation of an innovative joint MSc program in BME amongst the participating universities. Armenia is represented by two leading HEIs – the State Engineering University of Armenia (SEUA), and the Russian-Armenian (Slavonic) University (RAU), and an NGO working in the field of medical technologies – Armenian Association of Telemedicine (AATM). The project team from Armenia has by now held several working meetings locally and with the international partners, which have resulted in development of the new curriculum outline for the joint BME program, incorporating approaches and recommendations of the European project partners. The BME-ENA project is expected to provide an important platform for modernizing BME education in Armenia and bringing it in accordance with current European standards.

High-temperature superconducting thin-film circuit parameters

Processes in a high temperature superconducting thin film circuit with nonlinear active resistance and inductances are theoretically examined. A possibility to control values of equivalent parameters of the circuit by optical radiation modulated on the intensity is shown.

Analysis of parametric effects in high-temperature superconducting thin films

In this reference processes in a high temperature superconducting (HTSC) thin film circuit with nonlinear parametric resistance and inductance are theoretically examined. The fact that the active and reactive components of the impedance of HTSC film are modulated by the law of optical signal is accepted as a basic precondition for this discussion. By the analogy with the Josephson phenomenon we give certain phases for superconducting and normal states and accept that the alternating components of the photocurrent IPhi and photovoltage U created by the radiation can be presented as a phase difference between superconducting and normal states respectively. Based on this, the equation for the equivalent circuit of the film presents a complicated differential heterogeneous equation of second rank. As a particular state of the homogeneous equation has been investigated and the Mathieu equation has been obtained. In a result the expression for the gain in power is obtained, which depends on the parameters of the optical signal and thin film. The possibility to control the gain in power by the selection of various values of the depth of modulation of the active and reactive components of the surface impedance, the intensity of radiation and other parameters of the HTSC film is shown.