Repulsive firefly algorithm-based optimal switching device placement in power distribution systems

To achieve optimal configuration of switching devices in a power distribution system,this paper proposes a repulsive firefly algorithm-based optimal switching device placement method.In this method,the influence of territorial repulsion during firefly courtship is considered.The algorithm is practically applied to optimize the position and quantity of switching devices,while avoiding its convergence to the local optimal solution.The experimental simulation results have showed that the proposed repulsive firefly algorithm is feasible and effective,with satisfying global search capability and convergence speed,holding potential applications in setting value calculation of relay protection and distribution network automation control.

CMOS-compatible neuromorphic devices for neuromorphic perception and computing: a review

Neuromorphic computing is a brain-inspired computing paradigm that aims to construct efficient,low-power,and adaptive computing systems by emulating the information processing mechanisms of biological neural systems.At the core of neuromorphic computing are neuromorphic devices that mimic the functions and dynamics of neurons and synapses,enabling the hardware implementation of artificial neural networks.Various types of neuromorphic devices have been proposed based on different physical mechanisms such as resistive switching devices and electric-double-layer transistors.These devices have demonstrated a range of neuromorphic functions such as multistate storage,spike-timing-dependent plasticity,dynamic filtering,etc.To achieve high performance neuromorphic computing systems,it is essential to fabricate neuromorphic devices compatible with the complementary metal oxide semiconductor(CMOS)manufacturing process.This improves the device’s reliability and stability and is favorable for achieving neuromorphic chips with higher integration density and low power consumption.This review summarizes CMOS-compatible neuromorphic devices and discusses their emulation of synaptic and neuronal functions as well as their applications in neuromorphic perception and computing.We highlight challenges and opportunities for further development of CMOS-compatible neuromorphic devices and systems.

The effects of substrate temperature on ZnO-based resistive random access memory devices

Ag/ZnO/Zn/Pt structure resistive switching devices are prepared by radio frequency magnetron sputtering. The ZnO thin films are grown at room temperature and 400 ℃ substrate temperature, respectively. By comparing the data, we find that the latter device displayed better stability in the repetitive switching cycle test, and the resistance ratio between a high resistance state and a low resistance state is correspondingly increased. After 104-s storage time measurement, this device exhibits a good retention property. Moreover, the operation voltages are very low： -0.3 V/-0.7 V （OFF state） and 0.3 V （ON state）. A high-voltage forming process in the initial state is not required, and a multistep reset process is demonstrated.

The effects of substrate temperature on ZnO-based resistive random access memory devices

Ag/ZnO/Zn/Pt structure resistive switching devices are prepared by radio frequency magnetron sputtering.The ZnO thin films are grown at room temperature and 400 C substrate temperature,respectively.By comparing the data,we find that the latter device displayed better stability in the repetitive switching cycle test,and the resistance ratio between a high resistance state and a low resistance state is correspondingly increased.After 104-s storage time measurement,this device exhibits a good retention property.Moreover,the operation voltages are very low:-0.3 V/-0.7 V(OFF state) and 0.3 V(ON state).A high-voltage forming process in the initial state is not required,and a multistep reset process is demonstrated.

Comparison between Pt/TiO_2/Pt and Pt/TaO_X/TaO_Y/Pt based bipolar resistive switching devices

Nonvolatile memories have emerged in recent years and have become a leading candidate towards replacing dynamic and static random-access memory devices.In this article,the performances of T1O_2 and TaO_2nonvolatile memristive devices were compared and the factors that make TaO_2 memristive devices better than T1O_2 memristive devices were studied.TaO_2 memristive devices have shown better endurance performances（10~8times more switching cycles） and faster switching speed（5 times） than TiO_2 memristive devices.Electroforming of TaO_2 memristive devices requires ~ 4.5 times less energy than TiO_2 memristive devices of a similar size.The retention period of TaO_2 memristive devices is expected to exceed 10 years with sufficient experimental evidence.In addition to comparing device performances,this article also explains the differences in physical device structure,switching mechanism,and resistance switching performances of TiO_2 and TaO_2 memristive devices.This article summarizes the reasons that give TaO_2 memristive devices the advantage over TiO_2 memristive devices,in terms of electroformation,switching speed,and endurance.

Simulation of Low-Voltage Arc Plasma During Contact Opening Progress

This paper focuses on the simulation of the low-voltage arc with an opening contact. A controllable experiment setup with a rotating contact is designed to investigate the arc behaviour. Supported by the experiment, the phenomena of arc elongation and commutation in the case of rotating contact are simulated with the dynamic grid technique introduced. Under the given condition of the external magnetic field and the contact rotating velocity, the stagnation and rapid jump of two arc roots are observed by the calculated and experimental arc root displacement. The voltage of arc column can be divided into four phases and its sharp rising progress comes from the increase of the displacement difference between two arc roots in x direction.

A high-speed true random number generator based on Ag/SiNx/n-Si memristor

The intrinsic variability of memristor switching behavior can be used as a natural source of randomness,this variability is valuable for safe applications in hardware,such as the true random number generator(TRNG).However,the speed of TRNG is still be further improved.Here,we propose a reliable Ag/SiNx/n-Si volatile memristor,which exhibits a typical threshold switching device with stable repeat ability and fast switching speed.This volatile-memristor-based TRNG is combined with nonlinear feedback shift register(NFSR)to form a new type of high-speed dual output TRNG.Interestingly,the bit generation rate reaches a high speed of 112 kb/s.In addition,this new TRNG passed all 15 National Institute of Standards and Technology(NIST)randomness tests without post-processing steps,proving its performance as a hardware security application.This work shows that the SiNx-based volatile memristor can realize TRNG and has great potential in hardware network security.

Integrated optical switch matrices for packet data networks

Integrated circuit technologies are enabling intelligent,chip-based,optical packet switch matrices.Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable cost-effective,energy-efficient,and transparent data communications.InP integrated photonic circuits offer high-performance amplifiers,switches,modulators,detectors,and de/multiplexers in the same wafer-scale processes.The complexity of these circuits has been transformed as the process technologies have matured,enabling component counts to increase to many hundreds per chip.Active–passive monolithic integration has enabled switching matrices with up to 480 components,connecting 16 inputs to 16 outputs.Integrated switching matrices route data streams of hundreds of gigabits per second.Multi-path and packet time-scale switching have been demonstrated in the laboratory to route between multiple fibre connections.Wavelength-granularity routing and monitoring is realised inside the chip.In this paper,we review the current status in InP integrated photonics for optical switch matrices,paying particular attention to the additional on-chip functions that become feasible with active component integration.We highlight the opportunities for introducing intelligence at the physical layer and explore the requirements and opportunities for cost-effective,scalable switching.

Evaluation of 1.2 kV SiC MOSFETs in Multilevel Cascaded H-bridge Three-phase Inverter for Medium-voltage Grid Applications

A study is conducted to evaluate 1.2 kV silicon-carbide(SiC)MOSFETs in a cascaded H-bridge(CHB)three-phase inverter for medium-voltage applications.The main purpose of this topology is to remove the need for a bulky 60 Hz transformer normally used to step up the output signal of a voltage source inverter to a medium-voltage level.Using SiC devices(1.2-6.5 kV SiC MOSFETs)which have a high breakdown voltage,enables the system to meet and withstand the medium-voltage stress using only a minimal number of cascaded modules.The SiC-based power electronics when used in the presented topology considerably reduce the complexity usually encountered when Si devices are used to meet the medium-voltage level and power scalability.Simulation and preliminary experimental results on a low-voltage prototype verifies the nine-level CHB topology presented in this study.