Journal of Computational Electronics最新文献

Abstract

The modeling of self-heating in GaN-based devices is presented in this paper. A setup for DC I–V and short pulse I–V was used to characterize the device. This paper used four different methods to estimate self-heating, thermal resistance, and channel temperature in a GaN-based high electron mobility transistor (HEMT) fabricated on a SiC substrate. The procedures are basic and straightforward, making them suitable for determining self-heating. We concentrated on reducing the number of measurements needed to determine self-heating and/or channel temperature for any applied ambient temperatures. In addition, a summary of channel temperature for different GaN HEMTs found in—literatures is also presented. Finally, all of the findings are compared using a fair difference threshold. This work reflects an essential and comprehensive understanding of device technology.

The saturation of complementary metal–oxide–semiconductor (CMOS) technology in terms of area and power efficiency has given rise to advanced research on nanodevices. Memristors and their switching properties facilitate the implementation of various combinational logics and neural networks by potential replacement of the existing CMOS technology for edge computing devices. This work presents the design, implementation, and performance evaluation of memristor-based combinational logic circuits including adders, subtractors, and decoders via MATLAB Simulink and Cadence Virtuoso. In this work, we propose an optimized design of memristor-based combinational logic circuits and conduct a comparative study with the conventional method. The proposed memristor model is thoroughly validated experimentally for a high-density Y₂O₃-based memristive crossbar array and shows ultralow values in device-to-device and cycle-to-cycle variability. The power calculated from these circuits is reduced by more than 90% as compared to conventional CMOS technology implemented in Cadence Virtuoso. Moreover, the number of components utilized in the memristor-based logic circuits is significantly reduced in comparison to existing CMOS technology, which makes it more area-efficient and opens new avenues for the design and implementation of complex logic circuitry in few-micrometer scale.

This work focuses on the practical and reasonable synthesis of the fractional-order FitzHugh-Nagumo (FHN) neuronal model. First of all, the descriptive equations of the fractional FHN neuronal system have been given, and then the system stability has been analyzed according to these equations. Secondly, the Laplace-Adomian-decomposition-method is introduced for the numerical solution of the fractional-order FHN neuron model. By means of this method, rapid convergence can be achieved as well as advantages in terms of low hardware cost and uncomplicated computation. In numerical analysis, different situations have been evaluated in detail, depending on the values of fractional-order parameter and external stimulation. Third, the coupling status of fractional-order FHN neuron models is discussed. Finally, experimental validation of the numerical results obtained for the fractional-order single and coupled FHN neurons has been performed by means of the digital signal processor control card F28335 Delfino. Thus, the efficiency of the introduced method for synthesizing the fractional FHN neuronal model in a fast, low cost and simple way has been demonstrated.

In order to improve the practicability of Grover’s algorithm, this paper designs a flexible phase selection strategy and an initial state construction method for an unstructured database. The flexibility of the proposed algorithm is manifested in three aspects. First, it is suitable for an unordered database of any size, unlike traditional algorithms that must be an integer power of 2. In the existing approach, one must use padding when this requirement is not met. To this end, we propose a design method for an equal quantum superposition state containing any number of basis states. Second, the rotation phase in the search engine can be fixed to any value in the interval ((0, pi ]). We investigate the relationship between the rotation phase in the search engine and the probability of success and the number of search steps, and provide the formulas for calculating the probability of success and the number of search steps under any rotation phase. Third, for the case where the number of marked items is not known in advance, a specific search scheme using the search engine with rotation phase of (pi /3) is also given, and theoretical analysis shows that it can find a match in (O(sqrt{N/M})) search steps, where N is the total number of basis states and M is the number of marked states.

The bandwidth limitation of slow light may distort optical pulses, potentially affecting their practical application. Therefore, researching structures capable of overcoming this limitation could represent a valuable step forward. This theoretical work explores a 2D photonic crystal waveguide with high bandwidth. The optimized structure, comprised of Ge cylinders in an air background, is designed to be arranged in square lattices containing a line defect. The line defect consists of a series of half-cylinders, with their centers aligned with neighboring cylinders at half the lattice constant. This defect generates a waveguide mode that propagates along the line. Additionally, the group index and bandwidth of the mode were studied and optimized for different radii of the photonic crystal. With this relatively simple structure and the selection of appropriate geometric sizes, high bandwidth and a group-index-bandwidth-product of up to one could be achieved.

This paper analyzes the dynamic bursting of a mechanical oscillator with two strong irrational restoring forces when the external force changes slowly. The oscillator can exhibit both smooth and discontinuous characteristics depending on its geometry configuration, which is determined by the smoothness parameter. Using the fast-slow dynamics analysis method, we explore the equilibrium stability and bifurcation diagram of the unperturbed system, considering the external periodic excitation as a control parameter for both smooth and discontinuous cases. The bifurcation diagram shows two-fold/fold hysteresis cycles, which disappear as the smoothness parameter increases. Additionally, we examine the effects of the smoothness parameter and amplitude of the external excitation on the system. The study explores bursting oscillations and identifies two normal patterns—"fold/fold" and "node/node". Although there is no significant difference between smooth and discontinuous cases, the amplitude, shape, and time interval between spiking states of bursting oscillation depend on the smoothness parameter and external excitation amplitude. Furthermore, changing the smoothness parameter can create or eliminate bursting oscillations in the SD. To validate the numerical simulation results, the study implements the dynamics of a discontinuous oscillator in Field Programmable Gate Arrays (FPGA), which yields results that align with the numerical simulations.

In the current study, the first principle technique that depends exclusively on density functional theory is used to explore the structural, optoelectronic and thermoelectric properties of scandium-based ternary chalcogenides XScSe₂ (X = Li, Rb). The Full Potential Linearly Augmented Plane Wave (LAPW) method accompanied by PBE-GGA functional is used to determine the optimized lattice parameters of both chalcogenides. The valence band maxima (VBM) and conduction band minima (CBM) occur at the same wave vector having a significant direct band gap such as 1.42 eV for LiScSe₂ and 1.54 eV for RbScSe₂ leading to their semiconductor behavior. The results of the partial density of states (PDOS) of the considered substances reflect that 2s states of lithium, 3d states of each Rb and Sc, and 4p orbitals of Se are mainly responsible for the rise in electronic conductivity. The optical results show that these chalcogenides exhibit a significant rise in absorptivity and optical conductivity in the UV energy region when the photons are incident upon, where low reflectivity is noticed. The thermoelectric (TE) properties are also investigated through the BoltzTraP to understand the semi-classical Boltzmann transport theory. These results are prospective and provide a novel path for researchers to explore their potential applications in optoelectronic as well as thermoelectric devices.

The paper presents the design and simulation of a MEMS-based resonant viscosity sensor using a piezoelectric micro diaphragm. The sensor comprises a vibrating diaphragm as a resonating element with piezoelectric excitation and detection. As the viscosity of the liquid beneath the diaphragm changes, the resonant frequency also changes. A numerical model of a diaphragm is designed in the COMSOL Multiphysics FEM tool, and its resonance characteristics were studied with a fluid of different viscosities beneath it. To support the numerical simulation results, mesoscale experimentation was also performed using a stainless steel thin sheet as a diaphragm and also to verify the proof of concept of the proposed sensor. The major benefit of the proposed sensor is that it uses the resonance measurement principle and can be shown to offer good stable performance, resolution, reliability, and response time. The proposed sensor can also be showcased as a hand-held laboratory product for quick viscosity measurements.