George Angelov

Hydrogen bonding networks in transient state of beta-lactamase protein analogous to integrated circuits

Two hydrogen bonding networks (HBN) that are extracted from the β-lactamase protein are presented and studied in the present paper. The HBNs are formed in the active site of ß-lactamase when β-lactamase is in transient state (T1). The hydrogen bonds are modeled as three or four-terminal block elements analogous to classic electrical multi-terminal networks. Each block element is coded in Matlab and described by polynomials. Block elements are then included in a microelectronic circuits analogous to “proton networks”. The dynamic and static simulations with analogous circuits are carried out in Matlab. The results showed an analogy to a current source, amplifier, current mirror, and amplitude limiter.

Analysis of the impact of CNTFET model parameters on its transfer and output characteristics

The influence of internal parameters on transfer and output characteristics of a Carbon Nanotube Field Effect Transistor are studied in this paper. For the purposes of the study a CNTFET compact model is used. The compact CNTFET model is coded in Verilog-A and it is simulated in Cadence Spectre circuit simulator. In particular, we have examined how the transfer and output characteristics are altering when changing single parameters or sets of parameters. To compare the simulations results a cost function consisting of the two parameters is employed to quantify the impact of 430 model parameters. The sum of total 430 model parameters are examined and 59 are found to have negligible or no impact on output static characteristics. Three groups of internal model parameters have been recognized, according to their impact on output static characteristics.

Microelectronic circuit emulating Hydrogen Bonding Network of Green Fluorescent Protein

Hydrogen Bonding Network in active site of wild type Green Fluorescent Protein during the A→A* state is modeled. A microelectronic equivalent circuit is developed on its basis to emulate the operational principle of the Hydrogen Bonding Network. It is coded in Matlab to investigate its static and dynamic behavior. Output characteristics of static analysis are similar to inversed tunnel diode. The dynamic analysis show that the circuit can operate as amplifier, modulator and amplitude limiter.

Parameter extraction, optimization, and simulation of EKV model using MATLAB

An implementation of the EKV model in MATLAB is presented. Modules for output characteristics, transfer characteristics, transconductances, and parameter extraction are developed. They enable simulations of the respective characteristics under various conditions and provide user-friendly interface. Very good agreement between simulation results (EKV) and reference model (BSIM3v3) is demonstrated. The numerical calculation of the EKV model equations and the transconductances are optimized using appropriate mathematical techniques.

SRAM design based on carbon nanotube field effect transistor's model with modified parameters

The paper presents a design of SRAM circuit using CNTFET transistors. The complete model describing CNTFET, developed in Stanford University is modified for the purpose of designing a 6T (2×2) SRAM memory cell. The simulation results of the CNTFET SRAM memory cell manifest usability and applicability of the modified CNTFET model in designing digital circuits. The simplified CNTFET model is coded in Verilog-A and is implemented as a symbol in Cadence standard cell libraries. In order to develop a simplified CNTFET model, 430 complete model parameters are studied and estimated. The impact of the complete model parameters over the output and transfer static characteristics has been taken into consideration and parameters with effect lower than 0.0025% are neglected.

Computer modeling of graphene nanoribbon interconnects

In this paper computer models are developed of graphene nanoribbon (GNR) interconnects. A multilayer GNR interconnect model is created, as well as an accurate computer interconnect model based on ABCD parameters. Investigation in the frequency and in the time domain is performed. Computer SPICE models are also created taking into account the frequency effects in GNR interconnects. The results are compared to measured data obtained from referenced sources and thus have been verified.

Circuit modeling of Green Fluorescent Protein's hydrogen bonding network in cadence

A library of block-elements that mimics the behavior of the hydrogen bonds of Green Fluorescent Protein is created in Cadence for bioelectronics applications. A circuit is designed with these elements that model the architecture and behavior of the analogous hydrogen bonding networks of the protein. The circuit is studied by DC and transient analyses. The DC analysis shows that the output voltage is a linear function of the input voltage and that the output current is a non-linear function of the output voltage. This IV-characteristic clearly shows three operating regions. Depending on the bias points the circuit inspired by the hydrogen bonding networks operates as an amplifier, modulator and amplitude limiter.

A model for reverse electrowetting with cost-effective materials

This paper, presents a model to predict the energy output from reverse electrowetting energy harvesting system with use of cost-effective materials. Reverse electrowetting on dielectric allows energy to be harvested from spontaneous aperiodic mechanical movements, where conventional energy harvesting approaches are not suitable for due to low energy conversion efficiency and frequency.

Parameterized SPICE models of carbon nanotube interconnects

Parameterized computer SPICE models of carbon nanotube (CNT) interconnects are developed in the paper. The nonlinear I-V characteristic of a CNT is described. RLC models of an isolated single-walled CNT (SWCNT), as well as of SWCNT bundle interconnect are created. Based on the SWCNT bundle model a parameterized computer RLC model is created in the form of hierarchical block. The parameterization of the block gives great freedom and possibilities for further indept investigation on the topic. Computer SPICE models of higher accuracy for SWCNT bundle interconnect are proposed based on two-port Y-parameter representation. Verification is performed to confirm the applicability of the developed computer models.

Design and investigation of Hall effect micro-sensors

The requirements for precision integrated sensors are constantly increasing and the new techniques in the circuit design are of great importance. In this paper a new technology approved Hall effect microsensors are presented, which experimentally prove improved sensors characteristics.