Complementary GaAs SIS FET inverter using selective crystal regrowth technique by MBE
A first complementary GaAs semiconductor-insulator-semiconductor (SIS) FET inverter has been fabricated by constructing n-channel and p-channel GaAs SIS FET's on a single LEC GaAs substrate using MBE selective crystal regrowth technique. The fabricated inverter shows an inverter operation as a really low-power complementary inverter.
Complementary p-MODFET and n-HB MESFET (Al,Ga)As transistors
A complementary transistor structure that utilizes a p-channel modulation-doped FET (p-MODFET) to produce improved p-channel characteristics if reported for the first time. The structure also includes a new type of n-channel MESFET in which the electrons are confined by an n-p heterojunction barrier (n-HB MESFET). The complementary transistor pair is fabricated on a novel MBE-grown n-GaAs/p-(Al,Ga)As/i-GaAs heterostructure. The experimental current-voltage characteristics are presented and demonstrate that this is a promising approach for the development of GaAs-based high-speed complementary logic circuits.
Computer-Aided System of Virtual Testing of Gas Turbine Engines
The article describes the concept of a virtual lab that includes subsystem of gas turbine engine simulation, subsystem of experiment planning, subsystem of measurement errors simulation, subsystem of simulator identification and others. The basis for virtual lab development is the computer-aided system of thermogasdynamic research and analysis “ASTRA”. The features of gas turbine engine transient modes simulator are described. The principal difference between the simulators of transient and stationary modes of gas turbine engines is that the energy balance of the compressor and turbine becomes not applicable. The computer-aided system of virtual gas turbine engine testing was created using the developed transient modes simulator. This system solves the tasks of operational (throttling, speed, climatic, altitude) characteristics calculation, analysis of transient dynamics and selection of optimal control laws. Besides, the system of virtual gas turbine engine testing is a clear demonstration of gas turbine engine working process and the regularities of engine elements collaboration. The interface of the system of virtual gas turbine engine testing is described in the article and some screenshots of the interface elements are provided. The developed system of virtual gas turbine engine testing provides means for reducing the laboriousness of gas turbine engines testing. Besides, the implementation of this system in the learning process allows the diversification of lab works and therefore improve the quality of training.