SYNTHESIS AND EVALUATION OF ANTIMICROBIAL ACTIVITY OF PHENYL AND FURAN-2-YL[1,2,4] TRIAZOLO[4,3-a]QUINOXALIN-4(5H)-ONE AND THEIR HYDRAZONE PRECURSORS

A variety of 1-(s-phenyl)-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-one (3a-3h) and 1-(s-furan-2-yl)-[1,2,4]triazolo[4,3- a]quinoxalin-4(5H)-one (5a-d) were synthesized from thermal annelation of corresponding hydrazones (2a-h) and (4a-d) respectively in the presence of ethylene glycol which is a high boiling solvent. The structures of the compounds prepared were confirmed by analytical and spectral data. Also, the newly synthesized compounds were evaluated for possible antimicrobial activity. 3-(2-(4-hydroxylbenzylidene)hydrazinyl)quinoxalin-2(1H)-one (2e) was the most active antibacterial agent while 1-(5-Chlorofuran-2-yl)-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-one (5c) stood out as the most potent antifungal agent

Journal of Telecommunications and Information Technology, 2004, nr 1

kwartalni

Analytical predictive 2d modeling of pinch-off behavior in nanoscale multi-gate mosfets

In this thesis the pinch-off behavior in nanoscale Multi-Gate MOSFETs was reviewed and with compact models described. For this a 2D approach with Schwarz-Christoffel conformal mapping technique was used. A model to calculate the current in single gate MOSFETs was derived and compared to device simulations from TCAD Sentaurus down to 50nm. For the DoubleGate MOSFET a new way to define the saturation point was found. A fully 2D closed-form model to locate this point was created. It was also found that with quantum mechanics effects a pinch-off point can occur and can be described with the same model. Furthermore the model was extended to describe the coupled pinch-off points in an asymmetrical biased DoubleGate MOSET with an even an odd mode. Also the saturation point behavior in FinFETs was examinated

A physics-based model of SiC-based MESFETs

Silicon Carbide (SiC) has been investigated as an alternative material to Silicon (Si) for enhancing the power-handling capability of semiconductor devices for simultaneous high-temperature and high frequency applications. Its high thermal conductivity, high bandgap, low permittivity, high saturation velocity, moderate mobility, material hardness and chemical inertness make it a prime candidate for power electronics, heat and light sensors, and MEMS applications. The MESFET is the most viable power transistor based on SiC. The performance of SiC MESFETs is limited by trapping and thermal effects. A physics-based analytical model of the SiC MESFET incorporating trapping and thermal effects is reported. The model takes into account the field and temperature dependencies of carrier transport parameters and carrier trapping effects. Both surface and substrate traps have been incorporated in the model to calculate the observed current slump in the I-V characteristics. The trapping and detrapping from surface traps control the channel opening at the drain end of the channel that requires the drain resistance to be gate and drain voltage dependent. The substrate traps capture channel electrons at high drain bias when the buffer layer is fully depleted resulting in current collapse at low drain bias in the following I-V trace. The detrapping of the captured electrons is initiated with the increasing drain bias and the channel electron concentration increases which is accelerated by increased thermal effects. As a result, restoration of collapsed drain current is obtained before the trapping effect is reinitiated at high drain bias. The calculated results using the current model are in good agreement with experimental data. A small-signal model for the MESFET has also been proposed. Calculations for the output conductance, the transconductance, the gate-source and gate-drain capacitance has also been presented

Computer Simulation and Device Physics of SiGe Heterojunction Bipolar Transistors

Recent advances in semiconductor growth technology have enabled the growth of SiGe strained layers on silicon substrates. Si/SiGe technology has a promising future, especially in microwave HBT applications. This work describes the development of an existing two-dimensional drift-diffusion device simulation program for accurate modelling of SiGe heterojunction bipolar transistors (HBT\u27s). PUPHS2D (Purdue University Program for Heterostructure Simulation in Two Dimensions) was formulated by Paul Dodd [Dod89] as an AlGaAs/GaAs HBT simulation tool. This work describes the extension of this program to the silicon and Si 1|_xGex material systems. The computer model allows the user to explore internal device physics as well as terminal characteristics of a device. Field-dependent mobility has been added to the program in order to more accurately compute high-field transport phenomena. The simulation tool is used to study the performance of silicon bipolar transistors and Si/SiGe HBT\u27s, and these results are presented in chapter 4

Cutting Edge Nanotechnology

The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters