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Antennas operating at the high-frequency (HF) band (3–30 MHz) are frequently electrically small due to the large wavelength of electromagnetic waves (10–100 m). However, the bandwidth-efficiency products of passively matched electrically small antennas (ESAs) are fundamentally limited. Wideband HF waveforms using bandwidths of 24 kHz or more have recently received significant attention in military communications applications. Efficiently radiating such signals from conventional passive ESAs is very challenging due to fundamental physical limits on bandwidth-efficiency products of ESAs. However, active antennas are not subject to the same constraints. In this work, we present the design and experimental characterization of a high-power, class-E active ESA with enhanced bandwidth-efficiency product compared to that of passively matched ESAs. Specifically, the proposed class-E active ESA can radiate wideband HF signals with bandwidths of 24 kHz or more at 3 MHz (fractional bandwidths of ≈ 1 % – 4 %), with total efficiencies ranging from 40 % up to 80 % depending on the modulation type and radiated power levels approaching 100 W. Our approach uses a highly efficient, integrated class-E switching circuit specifically designed to drive an electrically small, high-Q HF antenna over a bandwidth exceeding 24 kHz at 3 MHz. Using a high-Q RLC antenna model, we have successfully demonstrated wideband binary ASK, PSK, and FSK modulations with the proposed class-E active ESA. Experimental results indicate that the bandwidth-efficiency product of this class-E active ESA is 5.4–9.8 dB higher than that of an equivalent passive design with the same data rate and bit-error-rate. [ABSTRACT FROM AUTHOR]

NaYF 4 :30%Er-NaYF 4 -NaYF 4 :20%Ho-NaYF 4 core–shell nanocrystals, which exhibit distinct upconversion (UC) luminescence in the green, yellow, and red regions under 1530 nm, 980 nm, and 1150 nm laser excitation, respectively, have been synthesized. These nanocrystals were subsequently encapsulated within a WO 3 hydrogel matrix with photochromic properties. The nanocrystals underwent a color transition to dark blue upon exposure to 365 nm ultraviolet light, a change that is reversible and allows for dynamic modulation of the UC luminescence. The integration of this nanocrystal-hydrogel system with a silicon-based photodetector facilitates a rapid reduction in current, enabling "hard switching" without the need for continuous 365 nm irradiation. Furthermore, irradiation at 365 nm induces a gradual decrease in current, which can slowly recover, thus achieving a "soft switching" effect. [Display omitted] Optical switches are increasingly acknowledged for their potential advantages over mechanical counterparts in various domains. However, research on optical switches remains relatively nascent, primarily focusing on applications like anti-counterfeiting, switching chemical reactions, etc., while neglecting the control of photocurrent switching. Here, we have developed NaYF 4 :30 %Er-NaYF 4 -NaYF 4 :20 %Ho-NaYF 4 core–shell nanocrystals with unique upconversion (UC) multi-color emission properties under 1530 nm, 980 nm and 1150 nm laser excitations. These nanocrystals allow for optical control of circuit switching by modulating photocurrent signals in photosensitive circuits. The UC emission is due to the self-sensitization of rare earth ions in the core and shell. By adjusting the intermediate shell thickness, we have optimized the luminescence and investigated the mechanism. Combining these nanocrystals with a WO 3 quantum dots (QDs) photochromic hydrogel, dynamic variation of UC emissions could be realized. Moreover, by combining with a commercial silicon photodetector, we constructed a photosensitive circuit demonstrating the modulation of photocurrent signal output and realized the "hard switching" of rapid circuit cutoff. Furthermore, by using the photochromic effect of WO 3 QDs, the "soft switching" of slow circuit cutoff and recovery were also achieved. This work has significant implications for the development and application such as energy management system and smart home of optical switches in various fields. [ABSTRACT FROM AUTHOR]

This work presents an approach based on signal processing and artificial intelligence (AI) to identify the pre-insertion resistor (PIR) and main contact instants during the operation of high-voltage SF6 circuit breakers to help improve the settings of controlled switching and attenuate transients. For this, the current and voltage signals of a real Brazilian substation are used as AI inputs, considering the noise and interferences common in this type of environment. Thus, the proposed modeling considers the signal preprocessing steps for feature extraction, the generation of the dataset for model training, the use of different machine learning techniques to automatically find the desired points, and, finally, the identification of the best moments for controlled switching of the circuit breakers. As a result, the models evaluated obtained good performance in the identification of operation points above 93%, considering precision and accuracy. In addition, valuable statistical notes related to the controlled switching condition are obtained from the circuit breakers evaluated in this research. [ABSTRACT FROM AUTHOR]

[Display omitted] Perfluorocarbon is commonly used as a coolant, chemical reaction carrier solvent, medical anti-hypoxic agents and blood substitutes. The realization of non-contact complex manipulation of perfluorocarbon liquids is urgently needed in human life and industrial production. However, most liquid-repellent interfaces are ineffective for the transport of ultra-low surface tension perfluorocarbon liquids, and struggle to maintain good durability due to unstable air or oil cushions in the surface. Therefore, preparing surfaces for stable non-contact complex manipulation of ultra-low surface tension droplets remains a challenge. In this paper, a novel solution, a photothermal responsive droplet manipulation surface based on polydimethylsiloxane brushes, has been reported. On this surface, droplets with different surface tensions (as low as 10 mN/m) can be efficiently manipulated through induced near-infrared light. Notably, this surface maintains its effectiveness after exposure to extreme anthropogenic conditions. The interface effect between perfluorocarbon droplets and polydimethylsiloxane brushes by near-infrared light-induced was investigated in detail. In addition, ultra-low surface tension droplets demonstrate the ability to transport solid particles. The conductive droplets exhibit sophisticated manipulation realizing the controlled switching of smart circuits. This research opens up new possibilities for advancing the capabilities and adaptability of ultralow surface tension droplets in a range of applications. [ABSTRACT FROM AUTHOR]

Short-circuit currents in autonomous and isolated electrical complexes today are approaching the switching capacity of operated circuit breakers. Since the existing equivalents cannot ensure the necessary reliability of power supply to consumers in emergency situations, it is pertinent to assess the need for developing new types of current-limiting devices (CLDs). This paper proposes an electrical circuit of a semiconductor current-limiting device based on a step-down DC-DC converter, where the main switch is a thyristor with an artificially switched circuit. Transient processes during the operation of the device are considered in detail. A mathematical model of the device is also provided. This model was verified by modeling the CLD circuit in MATLAB Simulink. In turn, the validity of the computer model used was proven experimentally. During the experiments, the current-limiting efficiency of the circuit was demonstrated, and its proposed mathematical model was also confirmed. This research was carried out as part of the project within the State Assignment FSEG-2023-0012. [ABSTRACT FROM AUTHOR]

Shunt active power filters (SAPF) play a vital role in power systems. Integration of renewable energy sources and electrical vehicle (EV) charging stations proliferate in the modern power system. In such scenario, SAPF is an efficient method for improving power quality. The article suggests a SAPF with multilevel cascaded H-bridge inverter using the instantaneous real and reactive power (P–Q) theory based control technique to derive reference currents for the compensation unit from active and reactive power to suppress harmonics present in the power system. The conventional-proportional integral (PI) and intelligent-fuzzy logic controller (FLC) were used as voltage controllers for maintaining the DC link voltage. The article proposed an aggregated PWM signal-switching circuit for balancing the individual capacitor voltage. The proposed system harmonic results are compared with conventional triangular PWM and aggregated PWM. The proposed switching circuit balanced the individual capacitor voltage and minimized the total harmonic distortion (THD) in the sinusoidal source voltages and currents. Simulation and prototype results reveals that proposed aggregated PWM system with FLC dominates the conventional PI controller. [ABSTRACT FROM AUTHOR]

When attempting to suppress structural vibrations employing a magnetostrictive transducer, owing to the control force is generated from current, a larger amplification of the current entails superior control performance. The semi-active control theory uses the synchronized switching damping (SSD) technique for structural vibration suppression while requiring a minimal energy supply. However, the absence of external energy input limits the current amplification performance. To address this limitation, this study proposes a novel method that combines semi-active vibration suppression method with negative capacitance to improve the current amplification performance. The proposed circuit switches the circuit status between shunt, inductor-capacitor (LC) electrical oscillation, and negative capacitance circuits. A mathematical model was employed to analyze the current operation, suppression performance, and robustness of the proposed circuit. Further, machine learning and kernel regression model were employed to predict the optimal control force gain. Validation experiments conducted on a 10-bay truss structure identical to the simulation model show that the experimental results align with the simulation predictions. The vibration suppression rates of the proposed method under single-mode and multiple-mode vibrations reached 85.8% and 78.3%, respectively, which are 2.64 and 1.89 times higher than those achieved by conventional methods. [ABSTRACT FROM AUTHOR]

In this paper, a novel state-dependent switching (SDS) method for switched systems with hybrid delayed impulses is proposed, which is different from the conventional approach of pre-setting the switching instants. First, for the SDS method involving delayed impulses, two preconditions, namely, coverage and overlap, are guaranteed. Then, by the Lyapunov stability theory and the proposed SDS strategy, the unified stability criteria of the switched systems under hybrid delayed impulsive control are obtained. Moreover, we discover that the impulsive delay has a double effect, that is, undermining and promoting system stability, which is contingent on the stability of the original systems. To validate the effectiveness of our results, we provide illustrative examples involving circuit switched networks. [ABSTRACT FROM AUTHOR]

This paper presents a new capacitor charger for energy-harnessing applications such as energy transfer from a low-power battery to a load capacitor. The proposed structure uses a switching technique for step-by-step charging of the load capacitor. It comprises a control section, output stage metal-oxide-semiconductor field-effect transistors, and an external inductor. In order to improve the circuit efficiency under different power transfer scenarios, the switching capacitor charger operates at the boundary of continuous conduction mode and discontinuous conduction mode. Two blocks of peak current controller and zero current detector have been employed in a feedback loop to control the inductor current, which resulted in conduction power dissipation reduction. Also, the circuit with switching at low frequencies significantly reduces the switching loss. The performance of the proposed circuit is demonstrated using theoretical elaborations. In addition, the proposed structure is evaluated and simulated in a 0.18 μ m standard complementary metal-oxide semiconductor technology. Based on the obtained results, the efficiency of the presented circuit at 15.62 mW input power is 96%, and the charging time is about 0.54 ms, which is suitable for low-power applications. [ABSTRACT FROM AUTHOR]

Summary: The paper designs an efficient three‐phase soft‐switching inverter with asymmetric auxiliary circuits, which is beneficial for further miniaturization and efficiency optimization. Only two auxiliary switches, one resonant inductor, and three resonant capacitors make up simple asymmetric auxiliary circuits of each phase, contributing to the reduction of power loss and hardware cost. As soon as the simple auxiliary circuits get involved in the operation of the designed inverter, main switches can realize zero‐voltage switching within the entire load range. The reduction of power loss of auxiliary circuits and main switches is conducive to further efficiency optimization. The paper expounds every operating status during one switching period. The relevant experimental waveforms make known that switching devices can realize soft‐switching. The efficiency reaches 99% at rated operation status of the designed inverter, confirming that the designed inverter has superiority over comparison objects in the experiment with regard to the efficiency. Thus, the structural simplification of auxiliary circuits is an effective method for further miniaturization and efficiency optimization. [ABSTRACT FROM AUTHOR]

Five-level voltage source inverter (VSI) is a power inverter topology generating a five-level output voltage waveform. This inverter topology can reduce harmonics distortion to be lower compared to a conventional twolevel inverter. In practical, delay of gating signals is unavoidable during switching operation of power semiconductor switches. Adding dead time in the gating signals of VSI's power switches is mandatory to avoid short circuit during switching operation. However, the dead time of the inverter's switching signals causes low frequency harmonics and distortion of inverter's output waveforms. In this paper, a different multicarrier sinusoidal pulse-width modulation (SPWM) method with harmonics suppression capability was proposed and applied in the three-phase open-connection load five-level inverter. The proposed modified SPWM was tested using computer simulation of Powersim (PSIM) software. The measured output waveforms of the five-level VSI at different power factor conditions are presented and analyzed. The total harmonics distortion (THD) values of inverter's output current were suppressed using the proposed SPWM method to be less than 1%. The test results showed that the proposed modified SPWM method was able to reduce the distortion (THD) of alternating current (AC) waveform, and increase the quality of the inverter's output power. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents some methods of direct torque control (DTC) improvement for asynchronous machine (AM) with PWM inverter. Asynchronous machine DTC is recognized to have a straightforward control structure and work similarly to field orientation control (FOC). Two new strategies are presented to retain this control structure while simultaneously improving the switching frequency and stator flux estimate performances of the DTC drive. Finally, some proposed schemes for improved DTC and simulation results are presented. [ABSTRACT FROM AUTHOR]

Abstract Silicon carbide (SiC) MOSFETs are garnering widespread attention due to their superior performance in high‐temperature, high‐frequency, and high‐voltage applications, emerging as the preferred power semiconductor devices in converters for photovoltaic power generation and new energy vehicles. However, SiC MOSFETs are prone to gate drive and drain‐source voltage oscillations during high‐speed switching events, resulting in diminished system efficiency, increased electromagnetic interference, reduced device safety, and even compromising the overall reliability of the converter. This paper introduces an oscillation suppression method based on a gate LCR parallel branch, aimed at optimizing the switching performance of SiC MOSFETs. A half‐bridge circuit model based on SiC MOSFET is established, and the mechanism of gate and drain‐source oscillation is meticulously analysed using the transfer function expression. Building upon this, the LCR parallel branch parameters are meticulously designed to introduce appropriate damping in the gate drive path, effectively mitigating oscillations. Experimental results demonstrate that the proposed design not only significantly reduces the amplitude of oscillations but also shortens the switch‐transition time. This enhancement effectively increases the switching frequency and reduces switching losses.

ABSTRACT This study proposes a fault estimation and tolerant anti‐disturbance switching control (ADSC) approach for the switched systems subject to the system fault and multiple disturbances. The fault dose not required to have a model. The disturbances contain the modeled unmeasurable part and the unmodeled measurable part. First, a composite switching estimator is constructed to simultaneously estimate the unavailable system state, fault and modeled disturbance. Then, by means of the estimator, a switching controller is developed to tolerant the fault and complement the modeled disturbance. Further, under the average dwell time relevant switching signals, criteria are established to ensure the fault estimation performance and robustness property for the switched systems. Finally, via implementing the presented fault estimation and tolerant ADSC scheme on a switched circuit system to regulate the charge and flux, the reasonability of the established result is verified. [ABSTRACT FROM AUTHOR]

Due to its unique features, the flyback converter is widely used to convert DC to DC power. This converter has a non‐minimum phase (NMP) dynamic behavior, which is one of its most significant disadvantages. By changing the topology of the flyback converter to a forward‐flyback (FF) converter, the dynamic behavior of the converter can be minimum phase (MP) while the main advantages of the flyback converter such as isolation of the output from the input and simple topology are maintained. This article proposes an innovative FF converter topology by doubling the forward path and adding only one diode and one capacitor. In addition to better dynamic behavior, the proposed double FF (DFF) converter has the same advantages as the conventional FF converter. A new method is used to obtain the transfer function of the output voltage to the duty cycle of the proposed converter. The converter is designed in continuous conduction mode (CCM) with minimum phase dynamics. Finally, simulation and experimental results of both conventional FF and the proposed DFF converters are obtained and compared to validate the superiority of the proposed converter. [ABSTRACT FROM AUTHOR]

AbstractThe electrical characterization of materials, particularly superconductors, semiconductors, and those undergoing metal-insulator transitions (MITs), relies significantly on resistivity and Hall measurements as a function of temperature. The van der Pauw four-point probe method is commonly used for such measurements, which involves resistance measurements for different circuit configurations connected to sample contacts. However, repeating these measurements at different temperatures is challenging and time consuming. This study introduces a novel approach utilizing a switching circuit controlled by an Arduino device and a LabVIEW program to automate resistance measurements for different electrical configurations. The effectiveness of this setup was demonstrated by testing V2O3 thin film samples deposited on Al2O3 (001) substrates using DC magnetron sputtering. The MIT temperature of the sample was 115 K during heating and 100 K during cooling. The sample exhibited p-type charge carriers with a Hall coefficient of 1.3 ± 0.1 x 10−4 cm3/C and Hall mobility of 1.7 x 10−1 cm2/V∙s, which is consistent with findings from other studies employing commercial equipment. [ABSTRACT FROM AUTHOR]

This investigation addresses the bumpless transfer fault detection (FD) problem within switched systems that possess unstable modes. A switched piecewise FD filter is developed as a residual generator by segmenting each dwell time interval. The transition between different filters precipitates pronounced, abrupt jumps in the residual signal. Consequently, a novel definition of the residual bumpless transfer performance is introduced to constrain the magnitude of residual fluctuations during switching instances. Additionally, an alternating switching strategy—characterized by slow and fast mode‐dependent average dwell time and supported by the multiple discontinuous Lyapunov function method—is devised to assure the asymptotic stability and the weighted H∞$$ {H}_{\infty } $$ performance of the augmented system. Concurrently, sufficient conditions for the solvability of the bumpless transfer FD problem are articulated in the form of linear matrix inequalities. Lastly, a switched buck‐boost circuit and a numerical example are presented to substantiate the merits of the proposed bumpless transfer piecewise filtering method. [ABSTRACT FROM AUTHOR]

Summary: This paper addresses the problem of adaptive robust safety‐critical control (ARSCC) for switched systems, where the safety of subsystems is not necessary. A novel ARSCC framework and an executable algorithm are presented to solve the ARSCC problem by finding a switching signal and controllers of subsystems. To estimate uncertainties, a novel switched piecewise‐constant adaptive law is presented, which guarantees a pre‐computable estimation error boundary. A single barrier function (SBF) method is proposed to ensure safety of switched systems with uncertainties, where the safety of subsystems is satisfied only in some subregion of a given safe set, instead of the whole safe set. Based on the SBF method, a novel state‐dependent switching law possessing different dwell times for different subsystems, is established to orchestrate the switching among potentially unsafe subsystems. As a special case of the SBF method, a common barrier function method is presented to achieve safety of switched systems with uncertainties under switching signals with given dwell times. In addition, some sufficient conditions are derived to obtain safety and asymptotic stability for switched systems with uncertainties by combining SBF and single Lyapunov function. Finally, a switched RLC circuit system is given to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

Organic-inorganic nanocomposites (RF/VOX) based on resorcinol-formaldehyde carbon matrix enriched by vanadium nanoparticles were synthesized by sol-gel method coupled with pyrolysis treatment. The crystallite structure of the resulting sample was investigated by X-ray diffraction technique, which shows the change of the V2O5 phase to V2O3 one under the pyrolysis temperature effect and the presence of vanadium carbide V8C7 phase in sample pyrolyzed at 1000 °C. The X-ray diffraction analysis proves the appearance of the graphite phase in all samples. Microscopic images (transmission electron microscopy and scanning electron microscopy) indicate the presence of macroporous carbon enriched with vanadium oxide in the form of nanobelts. These structural observations strongly affect the electrical properties. The current-voltage curves exhibit the presence of non-linear behavior for samples RF/VOX-625 and RF/VOX-650 which is identified as negative differential resistance NDR phenomenon. This NDR behavior appears at applied voltages of 51 and 180 V for samples RF/VOX-625 and RF/VOX-650, respectively. The Joule heating effect and filament formation were estimated as the origin of NDR behavior. The conductivity of our samples can be modulated by applying current. The coexistence of these two behaviors makes our samples promising for threshold switching and oscillator circuits. [ABSTRACT FROM AUTHOR]

This paper presents a novel method for nonlinear modeling GaAs field‐effect transistors (FETs) in a common gate (CG) configuration, which is crucial for the effective design and thorough assessment of RF switch circuits. By focusing solely on a CG‐based GaAs FET for RF switch device characterization and modeling, the modeling process is streamlined compared to traditional methods that involve both CG and common source (CS) devices. The direct measurement of both DC and RF characteristics using the CG device enhances the accuracy of model parameter extraction. This approach ensures consistency in model and simulation applications as the CG topology aligns with devices commonly found in RF switch circuits. Moreover, to enhance predictive accuracy regarding the dispersion effect, an improved equation of drain‐source current has been incorporated. The empirical validation of the model reveals good agreements in terms of insertion loss, isolation, and output power performance for the CG GaAs FET device, including a wide band single‐pole double‐throw (SPDT) switch Monolithic Microwave Integrated Circuit (MMIC). [ABSTRACT FROM AUTHOR]

The linear power amplifier (LPA) suffers from low power supply utilization in the DC power supply mode, leading to reduced output efficiency. This paper constructs an efficient power supply mode based on closed‐loop dynamic power supply system (CLDPSs). The CLDPSs can generate a pair of bipolar dynamic power supplies based on a predetermined signal to provide power to LPA, which can maintain a small voltage drop between the power supply and the output of LPA, thereby improving the power supply utilization of LPA. In addition, the study also focuses on the conflicting relationship between the output ripple and the dynamic performance of the CLDPSs, for which a new parametric design of the LC filter circuit is proposed, aiming to achieve a balance between these two aspects. Finally, a voice coil motor driving platform is constructed for experimental testing. The results demonstrate that the output ripple and dynamic performance of the CLDPSs can be balanced. In comparison to the DC power supply mode, the CLDPSs power supply mode can enhance the efficiency of LPA by 2 times while the driving accuracy of voice coil motor is basically unchanged. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South-Central Minzu University (Natural Science Edition) is the property of Journal of South-Central Minzu University (Natural Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Multicast has emerged as a primary communication pattern in datacenter networks due to the increasing demand for distributed data-parallel applications. To accelerate multicast traffic, the emerging reconfigurable circuit technology, which can establish circuit connections among switches, has been proposed as a promising paradigm for datacenter networks. This paper investigates how to accelerate the non-preemptive multicast flows in a demand-aware manner in reconfigurable datacenter networks. Firstly, the problem of scheduling circuit switches to minimize the average completion time is formulated and proved to be NP-hard. To address the conflicts between different multicast flows under the bandwidth constraint, a connection based hypergraph is constructed and then a two round matching algorithm is proposed under the bandwidth constraint. Additionally, to further reduce the average completion time, we introduce a method to utilize the remaining capacity of the ToR switches by splitting the unscheduled flows. The proposed algorithm is proved to have an approximation ratio of 2 2 n , where n represents the number of Top-of-Rack (ToR) switches. Finally, the extensive simulations demonstrate the effectiveness of the proposed algorithm in reducing the average completion time of flows compared to state-of-the-art algorithms. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The high-thrust linear motor used for the electromagnetic launch is switched by switches composed of anti-shunt thyristors. During the switching process, different current path states will appear, which will lead to changes in motor parameters and current fluctuation. Focusing on the air-core synchronous linear motor with parallel and series power supply, this paper analyzes the change in current path caused by the change in the trigger signal of anti-parallel thyristors in the process of sectionalized stator switching. The motor circuit model of the switching process is derived. A new sectionalized stators switching method is proposed to realize the smooth switching of the sectionalized stators linear motor. Finally, the correctness of the analysis and modeling is verified by simulation, and the effectiveness of the sectionalized stators switching method is tested by using the test prototype. [ABSTRACT FROM AUTHOR]

This article aims to test, measure and evaluate the quality of voice calls made in a mobile cellular network. A set of drive tests were conducted, during which logs were collected using specialized measurement terminals equipped with a dedicated voice evaluation application. Three different scenarios were considered: the first scenario consisted of a series of mobile-to-mobile calls in a circuit-switched (CS) domain over the GSM network, the second scenario involved similar calls using the VoLTE service in a packet-switched (PS) domain of a 4G network, and the third scenario employed an over-the-top (OTT) media service type via the WhatsApp application in the same PS domain of the 4G network. The measurement results highlight the user experience in each scenario and compare the voice quality evaluated through the Mean Opinion Score (MOS) across the CS and PS domains. The originality of this work consists of in situ measurements performed in Bucharest, Romania, providing detailed, context-specific insights regarding the network performance that can drive local improvements and support policy and investment decisions. [ABSTRACT FROM AUTHOR]

This paper presents a single-input multiple-output (SIMO) cascode low-noise amplifier with inductive degeneration for inter- and intra-band carrier aggregation. The proposed low-noise amplifier has two output ports for flexible operation in carrier aggregation combinations for band 30 and band 7. However, during inter- and intra-band operation, gain variation occurs depending on the output mode. To compensate for this, a switching circuit is proposed to adjust the degeneration inductor, optimizing gain performance for both modes. The switching operation can minimize the control for the dynamic range in the receiver system to support carrier aggregation. The designed low-noise amplifier was fabricated using a 65 nm CMOS process, occupying an area of 2.1 mm2. In inter-band operation, the small-signal gain was measured by 18.9 dB for band 30 and 18.6 dB for band 7, with the noise figures of 1.03 dB and 1.07 dB, respectively. For intra-band operation, the small-signal gain was 17.3 dB and 17.2 dB, with the noise figures of 1.3 dB and 1.41 dB. The IIP3 values were measured by −7.6 dBm and −6.7 dBm for inter-band, and −6.3 dBm and −6.2 dBm for intra-band. Power consumption was 8.04 mW and 7.68 mW in inter-band, and 17.04 mW and 17.64 mW in intra-band depending on the output configuration. [ABSTRACT FROM AUTHOR]

Many researchers have focused on molecular electronics, and this field can progress faster by applying semiconductors to molecular modeling. In this work, two middle rings of a bipyridine–biborinine molecular diode are rotated from 25∘ to 90∘ such that the current along the molecule is reduced. The current is minimum and almost zero at 90∘, while it is maximum at 25∘. Accordingly, considering these two angles, the molecule can act as a switching device when the two middle rings are rotated. The bipyridine–biborinine molecular diode is modeled considering the effect of rotation by including two resistors in the model. Two parallel diodes are used in this modeling for pyridine and borinine rings. The ideality factors of these diodes are varied based on the electronegativity of pyridine and borinine rings. This model is then applied to consider different molecular logic gates such as NAND, NOR, NOT, OR and AND gates, as well as molecular logic circuits (half adder and full adder), using the unique capabilities of the LTspice software. [ABSTRACT FROM AUTHOR]

Data encryption is an essential building block in modern electronic systems to prevent spying and hacking. Every day more and more objects produce electronic data, and this needs to be encrypted before being transmitted. Hence, designing devices, circuits, and systems for data encryption that can be integrated in all kinds of objects and that consume low amounts of energy is highly necessary. Here, this work reports the fabrication of flexible and transparent electronic circuits consisting of devices that exhibit threshold‐type resistive switching with a high degree of stochasticity. The cycle‐to‐cycle variability of switching voltages and state currents is significant but confined within a well‐defined range, which is consistent across multiple devices. This allows to design an efficient protocol for true random number generation. The circuits are fabricated with only synthetic 2D materials, can be fabricated in a scalable manner, and can be integrated in any object. [ABSTRACT FROM AUTHOR]

This paper focuses on the integration technology of electric vehicle motor driving system and on-board charging system. The front-stage bi-directional AC/DC converter time-multiplexes a three-phase bridge full-control circuit into a staggered parallel totem pole power factor correction circuit and a three-phase inverter circuit, which enables the on-board charging system to have a motor control function. It can form a bidirectional AC/DC converter which can realize the function of motor control. The rear-stage DC/DC converter can realize the energy exchange between power supply and power battery or power battery and motor through dual active bridge structure. The working characteristics of the front-stage circuit and the soft switching range of the rear-stage circuit are studied. The mathematical model of the front-stage circuit and the rear-stage circuit are established by small signal analysis, and the control strategy of the front-stage double-closed loop and the rear-stage double-loop competition is adopted. The PI controller parameters are designed by using the mathematical model of the system, and the stability of the compensated system is verified by the open-loop amplitude-frequency characteristic curve. The simulation model and experimental platform are established. The charging mode is verified by the electronic load and high voltage DC source simulate the power battery. The driving mode is verified by using the 5 kW permanent magnet synchronous motor. The simulation and experimental results verify the feasibility of the system to achieve charging and driving functions. [ABSTRACT FROM AUTHOR]

This study proposed a GMAW process modeling with a topology that includes two two-level rectifiers connected in parallel to operate under different transfer modes such as short circuit, mixed, spherical, and spray. The tests of the arc stability studied and compared to the experimental GMAW process of the PipeWorx 400 in order to know the effectiveness of the proposed model. The welding current and voltage, droplet diameter, and length of the weld wire can be easily extracted from the proposed model. This paper examined the dynamic behavior of the GMAW process under the healthy and faulty switch of the rectifiers, and proposed a new diagnostic technique based on the variations of the Boolean Mean Value (BMV) of the six currents of rectifiers. To estimate the droplet detachment frequency DDF, the technique of Single-Sided Amplitude Spectrum (SSAS) is applied to the welding current of the simulation model and experimental process. The obtained results showed a high similarity in performance between the proposed simulation model and the experimental process. The SSAS technique is capable of estimating the accurate DDF value in both healthy and faulty cases of the IGBT switch. The proposed BMV diagnostic technique proved the exact location of the open circuit switch of the rectifiers in a very short time up to 7 ms. [ABSTRACT FROM AUTHOR]

Summary: At present, many DNA logic circuits have been successfully constructed. However, advanced complex DNA computing tasks with simple structure, fast response, and modularization still remain a huge challenge. In this paper, molecular switch circuits (MSCs) are constructed based on DNA strand displacement to improve above problems. At first, molecular switch is constructed, which is the basic element for building logic circuits. Next, the functions of AND, OR, Fan‐in, and Fan‐out are realized through switches cascading in series or parallel. Furthermore, switch canvas strategy is explored to obtain the shortest reaction path and highest output concentration for circuits. Finally, a novel strategy of integrating computing module using molecular switches is proposed. Here, we construct a half‐adder, half‐subtractor, and a 9‐bit parity checking circuits to verify its feasibility. Compared with the classical monorail and dual‐track logic circuits, the structure scale is reduced by more than two times, and the DNA strands are decreased by more than four times, which effectively reduces the circuit complexity and raises the reaction speed. The above results show that MSC strategy has a great potential to construct large‐scale DNA circuits and provides a development model for the scalability and modularity of biological computing. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes an integrated modular equalization circuit for energy storage systems. This integration is achieved by reusing the half‐bridge circuit into the cell‐level equalization circuit and the module‐level equalization circuit, thereby simplifying the system. The proposed equalization circuit has a good equalization effect and balancing speed. In addition, all high‐frequency switches in the equalization circuit can achieve zero voltage switching (ZVS), and the equalization circuit has high efficiency. This paper provides a detailed analysis of the equalization circuit. Mathematical models for cell‐level and module‐level equalization circuits have been derived for optimal design and control of the equalization circuit. The experimental results have good consistency with the analytical results. [ABSTRACT FROM AUTHOR]

In the current communication era, 2G voice services coexist with higher generation mobile network voice services like Voice over Long Term Evolution (VoLTE) in 4G and Voice over New Radio (VoNR) in 5G. Subscribers registered in the 5G network, but their voice option is in 4G so voice calls can be handled through the Evolved Packet System (EPS) Fallback or Radio access technology (RAT) Fallback. Similarly, subscribers register in a 4G network, but their voice option is in 3G or 2G so voice calls can be handled through Circuit Switched Fallback (CSFB). To provide uninterrupted voice service in such wireless networks usually handoff calls (HCs) receive higher priority than new calls (NCs). So, some guard radio resources (i.e., channels in 2G or RBs in 4G or 5G) may be reserved in each cell to handle this type of HCs. If more channels are reserved for HCs, then the handoff call-dropping probability (HCDP) will be decreased and at that time the new call-blocking probability (NCBP) will be increased. So, by considering the target HCDP if channels are reserved for HC, then HCDP will remain below the target and NCBP will be minimum. In this paper first, we proposed an optimal channel reservation (OCR) policy that reserves guard channels according to the given target HCDP. Second, we compared our OCR policy with fractional channel (FC), limited fractional channel (LFC), and uniform fractional channel (UFC) policies. Finally, we observed the performance of all these policies considering the Global System for the Mobile Communication (GSM) network. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) MOSFETs are garnering widespread attention due to their superior performance in high‐temperature, high‐frequency, and high‐voltage applications, emerging as the preferred power semiconductor devices in converters for photovoltaic power generation and new energy vehicles. However, SiC MOSFETs are prone to gate drive and drain‐source voltage oscillations during high‐speed switching events, resulting in diminished system efficiency, increased electromagnetic interference, reduced device safety, and even compromising the overall reliability of the converter. This paper introduces an oscillation suppression method based on a gate LCR parallel branch, aimed at optimizing the switching performance of SiC MOSFETs. A half‐bridge circuit model based on SiC MOSFET is established, and the mechanism of gate and drain‐source oscillation is meticulously analysed using the transfer function expression. Building upon this, the LCR parallel branch parameters are meticulously designed to introduce appropriate damping in the gate drive path, effectively mitigating oscillations. Experimental results demonstrate that the proposed design not only significantly reduces the amplitude of oscillations but also shortens the switch‐transition time. This enhancement effectively increases the switching frequency and reduces switching losses. [ABSTRACT FROM AUTHOR]

This paper proposes an effective method to improve the power efficiency of the flyback converter in the continuous conduction mode (CCM). The proposed converter uses a simple passive circuit to reduce the switching power losses. The current through the output diode can be shifted to a new branch where one diode, one inductor, and one auxiliary winding of the transformer are included. The output diode current can be reduced to zero for the zero-current switching of the output diode. The additional inductor is used to control the changing rate of the additional diode current to reduce the reverse-recovery current. Keeping the simplicity of the passive method, the proposed converter improves the power efficiency compared to the conventional converter. The circuit configuration and the operation principle are described. The design considerations are presented, including the simulation verification. The experimental results for a 45 W prototype are discussed to evaluate the performance of the proposed converter. The proposed converter has achieved a power efficiency of 93.5% for the rated load condition, improving the power efficiency. The applications of the proposed converter are also discussed for the future research directions. [ABSTRACT FROM AUTHOR]

Resistive memory devices feature drastic conductance change and fast switching dynamics. Particularly, nonvolatile bipolar switching events (set and reset) can be regarded as a unique nonlinear activation function characteristic of a hysteretic loop. Upon simultaneous activation of multiple rows in a crosspoint array, state change of one device may contribute to the conditional switching of others, suggesting an interactive network existing in the circuit. Here, we prove that a passive resistive switching circuit is essentially an attractor network, where the binary memory devices are artificial neurons while the pairwise voltage differences define an anti-symmetric weight matrix. An energy function is successfully constructed for this network, showing that every switching in the circuit would decrease the energy. Due to the nonvolatile hysteretic function, the energy change for bit flip in this network is thresholded, which is different from the classic Hopfield network. It allows more stable states stored in the circuit, thus representing a highly compact and efficient solution for associative memory. Network dynamics (towards stable states) and their modulations by external voltages have been demonstrated in experiment by 3-neuron and 4-neuron circuits. The switching dynamics in resistive memory hardware enables efficient computations, such as stateful logic and temporal information processing. The authors show that a passive resistive switching circuit represented as an attractor network model provides high-capacity, compact and efficient solution for associative memory. [ABSTRACT FROM AUTHOR]

The ability to switch between rules associating stimuli and responses depend on a circuit including the dorsomedial prefrontal cortex (dmPFC) and the subthalamic nucleus (STN). However, the precise neural implementations of switching remain unclear. To address this issue, we recorded local field potentials from the STN and from the dmPFC of neuropsychiatric patients during behavioral switching. Drift-diffusion modeling revealed that switching is associated with a shift in the starting point of evidence accumulation. Theta activity increases in dmPFC and STN during successful switch trials, while temporally delayed and excessive levels of theta lead to premature switch errors. This seemingly opposing impact of increased theta in successful and unsuccessful switching is explained by a negative correlation between theta activity and the starting point. Together, these results shed a new light on the neural mechanisms underlying the rapid reconfiguration of stimulus-response associations, revealing a Goldilocks' effect of theta activity on switching behavior. Direct electrophysiological recordings in the human prefronto-subthalamic circuit show that behavioral switching requires an optimal level of theta activity to be successful, which is well accounted for by a negative modulation of a drift-diffusion model starting point. [ABSTRACT FROM AUTHOR]

This article proposes a new interleaved buck converter with a high step-down conversion ratio and soft-switching. The soft-switching conditions for the main IGBTs are achieved with the aid of a simple auxiliary circuit, which comprises a resonant inductor, a resonant capacitor, and a diode. A new interleaved buck converter is realized by adopting two auxiliary circuits separately connected to each one of the legs to provide zero voltage switching (ZVS) and zero current switching (ZCS) turn-on operation. The major advantages of this converter are reduced switching losses, a high step-down ratio, reduced voltage stresses, and no limitation on duty ratio. To validate the theoretical analysis, a laboratory prototype of a 200 V-60 V converter system has been developed and achieved an efficiency of 96% at 250 W output power. [ABSTRACT FROM AUTHOR]

Due to the reduction in transistor size, test engineers face a severe issue in power minimization. VLSI circuit's power dissipation has become a vital concern due to the switching activity of the Circuit Under Test (CUT). Switching activity is a significant factor in determining power consumption for CMOS VLSI circuits. In this paper, we formulate a distance estimation technique and reordering using the Tversky index. Here, the distance between the test vectors is calculated using the Tversky index with the formation of an adjacency matrix, and reordering is performed. The experimental results of the proposed method have been compared to different distance measures and existing techniques. It shows that the switching activity is reduced from 52.5% to 21.5%, and the average power reduction is from 42% to 14.6% when the distance is estimated on reordering using the Tversky index measure. Thus, the Tversky index distance measure performs better than the Hamming, gray, and Linear feedback shift register (LFSR) methods. Switching activity estimation for complex ISCAS circuits has been performed and compared with existing methods for superior performance. We have also developed a Built in Self-Test (BIST) for the C17 benchmark circuit, which uses the Tversky counter as a test pattern generator using the TANNER EDA tool. Thus, an efficient deterministic BIST for the C17 benchmark circuit was designed to detect all the stuck-at faults, and the same procedure can be used to create BIST for all CUT and precomputed test sets for real-time field testing. [ABSTRACT FROM AUTHOR]

The demand for high-gain, efficient, and costeffective power converters with simple control mechanisms to connect electric vehicle batteries to the grid is increasing. This study introduces a switched capacitor-based power boost converter circuit to meet these needs. The minimal number of power switches in the circuit simplifies control operations and improves practical applicability. The proposed converter boosts the battery pack voltage by a factor of 5 and 11 for duty ratios of 0.5 and 0.8, respectively, which is significant compared to conventional boost converters. However, designing an electromagnetic interference (EMI) filter is crucial when a power converter board requires the application of a wide range of switching frequencies to enhance electromagnetic compatibility (EMC) immunity. Therefore, as the next step, the EMI/EMC filter design stages were discussed for the proposed converter. For this purpose, 15 printed circuit board (PCB) design rules were checked using the Altium Designer EMI Design Rule Checker, and board EMI/EMC compatibility was analysed. The resonance between the power and ground layers in the PCB was assessed using the plane resonance analyser. The results of simulation and laboratory tests are presented, which confirms the theoretical studies. On the basis of the software results, the points on the electronic board most susceptible to visual interferences have been identified. To minimise these EMI/EMC errors, it is suggested to add electronic components, such as capacitors, at these points according to mathematical and software findings. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Oxygen vacancy engineering in metal oxides is a propitious route to modulate their resistive switching properties for memory and neuromorphic applications. This review provides an account of the research works on tailoring RS behavior in oxide thin-film-based memristor devices by oxygen vacancy engineering. We discuss the recent research progress on controlling oxygen vacancy concentration in metal oxide thin films and its impact on their resistive switching properties for application in electronic memory and neuromorphic computing devices. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The widespread of renewable energy sources often requires DC‐DC power converters with higher operational flexibility and voltage gain capability. The Y‐source converter offers significant features to fill this demand, but its performance can be negatively affected by coupled‐inductor leakage inductances. This paper presents simplified models for the Y‐source DC‐DC converter (YSDC) that, although not directly including the presence of leakage inductances, offer a satisfactory description of how the converter operates in terms of its steady‐state behavior, small‐signal dynamics, and estimation of power losses. These models allow for a comprehensive analysis of how non‐ideal components in the converter affect the determination of the YSDC voltage gain and efficiency and allow one to identify the most interesting design alternatives to satisfy the current and voltage stress constraints placed on the converter power switches, thus excluding undesired converter design alternatives. Experimental results with a 280 W real converter, using coupled‐inductor with leakage inductances, present results similar to those of switched circuit simulations and the derived models, thus confirming that the simplified models present satisfactory adherence to the real converter performance over the majority extent of the maximum duty cycle. [ABSTRACT FROM AUTHOR]

Railway signaling electromechanical devices (RSEDs) play a pivotal role in the railway industry. Normal wear and tear of these devices occur during day-and-night operation and even progressively develop into failures. Hence, it is imperative to predict the remaining useful life (RUL) for reliable services. However, there are three existing challenges in addressing the issue. To overcome these challenges, we introduce M 2 BIST-SPNet for RSEDs RUL prediction. The model incorporates advanced spatiotemporal feature extraction mechanisms, including a spatial-temporal attention-based convolution networks (STACN), multiple branches with multi-scale multifrequency module (MBM), and communication module (CM). Extensive experiments conducted on three typical object datasets (i.e., railway safety relay, EMU contactor, switch circuit controller) shows that the proposed approach has demonstrated state-of-the-art performance in long-term multiparameter prediction and RUL prediction. [ABSTRACT FROM AUTHOR]