Fast Switching Research Articles

A Local‐Dissociation Solid‐State Polymer Electrolyte with Enhanced Li+ Transport for High‐Performance Dual‐Band Electrochromic Smart Windows

AbstractWindows through heat exchange play a vital role in energy saving for realizing a net‐zero carbon emission society. Dual‐band electrochromic (EC) smart windows by dynamically regulate visible (VIS) and near‐infrared (NIR) light are necessary for improving both building energy efficiency and habitant comfort. However, the rational design of high‐performance electrochromic devices (ECDs) suffers sluggish EC response due to the slow ion transport. In this work, a locally dissociated Li+ concept is proposed to construct a solid‐state polymer electrolyte (SPE) with ultrafast Li+ transport. The succinonitrile (SN) is employed to loosen the Li+‐anion pair and the crystallographic C─O chain in the poly(ethylene glycol) methyl ether methacrylate (PEGMA) electrolyte by its strong solvation capability. The as‐prepared SPE shows a high ionic conductivity of 6.48 mS cm−1 at 30 °C and a high transmittance of >90%. The SPE‐based EC smart windows exhibited a fast switching speed (3.0/3.2 s for coloration/bleaching), a high coloration efficiency (CE) of 373.8 cm2 C−1, and a high optical modulation in the full solar spectrum (85%, 70%, 43% at 673, 1200, and 1600 nm, respectively). Finally, the SPE‐based EC smart windows shows three working modes with a temperature regulation range of 19.1 °C, exhibiting great potential in practical application.

Compensated Neural Network Training Algorithm with Minimized Training Dataset for Modeling the Switching Transients of SiC MOSFETs

Accurate modeling of the switching transients of SiC MOSFETs is essential for overvoltage evaluation, EMI prediction, and other critical applications. Due to the fast switching speed, the switching transients of SiC MOSFETs are highly sensitive to parasitic parameters and nonlinear components, making precise modeling challenging. This paper proposes a hybrid model for SiC MOSFET, in which the analytical model is treated as the basis to provide the fundamental waveforms (knowledge-driven), while the neural network (NN) is utilized to fit the high-order and nonlinear features (data-driven). An NN training method with augmented data is proposed to minimize the training datasets. Verification results show that, even though the NN is trained with the data from a single operating condition, the model can accurately predict switching transients of other operating conditions. The proposed methodology has the potential to co-work with the “black-box” or “grey-box” models to enhance the model accuracy.

Spectral optimization using fast kV switching and filtration for photon counting CT with realistic detector responses: a simulation study.

Photon counting CT (PCCT) provides spectral measurements for material decomposition. However, the image noise (at a fixed dose) depends on the source spectrum. Our study investigates the potential benefits from spectral optimization using fast kV switching and filtration to reduce noise in material decomposition. The effect of the input spectra on noise performance in both two-basis material decomposition and three-basis material decomposition was compared using Cramer-Rao lower bound analysis in the projection domain and in a digital phantom study in the image domain. The fluences of different spectra were normalized using the CT dose index to maintain constant dose levels. Four detector response models based on Si or CdTe were included in the analysis. For single kV scans, kV selection can be optimized based on the imaging task and object size. Furthermore, our results suggest that noise in material decomposition can be substantially reduced with fast kV switching. For two-material decomposition, fast kV switching reduces the standard deviation (SD) by . For three-material decomposition, greater noise reduction in material images was found with fast kV switching (26.2% for calcium and 25.8% for iodine, in terms of SD), which suggests that challenging tasks benefit more from the richer spectral information provided by fast kV switching. The performance of PCCT in material decomposition can be improved by optimizing source spectrum settings. Task-specific tube voltages can be selected for single kV scans. Also, our results demonstrate that utilizing fast kV switching can substantially reduce the noise in material decomposition for both two- and three-material decompositions, and a fixed Gd filter can further enhance such improvements for two-material decomposition.

Dynamic Mobile X-Haul Reconfiguration by Fast Network Switching for Low-Latency MEC Service

Dynamic Mobile X-Haul Reconfiguration by Fast Network Switching for Low-Latency MEC Service

Preparation and infrared shielding of polyaniline@MWCNTs flexible electrochromic device based on cotton fabric

Electrochromic fabric was formed by interfacial polymerization of polyaniline (PANI) and multi-walled carbon nanotubes (MWCNTs) on the surface of cotton cloth. The morphology and properties of the composite films were controlled by changing the content of multi-walled carbon nanotubes. The electrochromic properties of the fabric and its application in the field of near-infrared thermal shielding were studied. It is found that the electrochromic fabric with MWCNTs have better electrochemical and color-changing properties. Electrochromic fabrics achieve color changes from light yellow to yellow-green to dark green in the voltage range of -1.0 to 1.2V, and maintain a fast color switching time (2.15s for coloring, 1.89s for bleaching) after 600 cycles. The reflection contrast (ΔR) at 500nm is 23.01%. Moreover, the electrochromic devices are assembled with fabrics. The device has obvious discoloration and good bending stability. In addition, the thermal shielding is realized by using their reflection characteristics in the visual-near-infrared region. The results show that the electrochromic device has a low surface temperature at different environmental condition, and the thermal reduction from the original state to the bleached state is up to 3.8 ° C, indicating the potential application of the device in thermal regulation.

Investigation of a fast gate driver based on a half-turn planar transformer.

This paper presents a magnetically isolated gate driver for the fast switching of IGBT (Insulated Gate Bipolar Transistor) in compact pulsed power sources with sharp rising edges and flat-top pulses for the application of electromagnetic launch and food processing. The proposed gate driver is implemented based on a planar transformer with a half-turn winding arrangement to increase the amplitude of the driving voltage pulse. With the half-turn winding arrangement, the leakage inductance of transformers decreases by 31.1% compared to the interleaving structure. This decrease enables a fast rise time of the driving voltage pulse. Furthermore, the gate drivers are used to drive the IGBT switching a Blumlein pulse forming network. The results show that the di/dt of the applied commercially available Si IGBT is about 10.10 A/ns with a gate voltage of 50V and a gate capacitance charging time of about 88ns, proving the effectiveness of the gate driver and providing a high-performance driving scheme for the fast switching of Si IGBT.

On-chip deep subwavelength optomagnetic bistable memory based on inverse Faraday effect related nonlinearity in graphene waveguide ring resonators

Integrated optical devices that possess bistable characteristics are key elements for optical digital signal processing and all-optical computing. In this paper we report on an optomagnetic bistable memory based on the inverse Faraday effect related nonlinearity in graphene waveguide ring resonators. The effective magnetic field via the plasmon-induced inverse Faraday effect in the graphene resonator has two discrete stable states that represent logic one and logic zero and magnetic switching for memory operation can be achieved by injecting an optical pulse and momentarily blocking the bias input light. Our proposed optomagnetic bistable device based on a graphene magnetoplasmonic configuration has great potential for the development of next generation magnetic memory. It has benefits of ultrafast magnetization switching, simplicity of the considered structure, on-chip compatibility, and a deep subwavelength platform. It also enhances the nonlinear interaction due to strong confinement of the graphene plasmon modes and high-quality factor of traveling modes in the graphene ring resonator, and tunability and robustness by adjusting the gate voltages of the graphene sheets. These advantages will satisfy the demand for fast magnetization switching, low-energy consumption, and high-density recording required in future magnetic memories. Published by the American Physical Society 2024

Generalized Coherent Wave Control at Dynamic Interfaces

AbstractCoherent wave control is of key importance across a broad range of fields such as electromagnetics, photonics, and acoustics. It enables us to amplify or suppress the outgoing waves via engineering amplitudes and phases of multiple incidences. However, within a purely spatially (temporally) engineered medium, coherent wave control requires the frequency of the associated incidences to be identical (opposite). In this work, this conventional constraint is broken by generalizing coherent wave control into a spatiotemporally engineered medium is broken, i.e., the system featuring a dynamic interface. Owing to the broken translational symmetry in space and time, both the subluminal and superluminal interfaces allow interference between scattered waves regardless of their different frequencies and wavevectors. Hence, one can flexibly eliminate the backward‐ or forward‐propagating waves scattered from the dynamic interfaces by controlling the incident amplitudes and phases. The work not only presents a generalized way for reshaping arbitrary waveforms but also provides a promising paradigm to generate ultrafast pulses using low‐frequency signals. It has also implemented suppression of forward‐propagating waves in microstrip transmission lines with fast photodiode switches.

Abstract 4137103: Myofibril Mechanics and Transcriptomic Profiling Confirm Distinct Phenotype of TNNI3- Cardiomyopathy Mouse Model

Introduction: Cardiac troponin I (cTnI, TNNI3 gene) is a highly conserved subunit of the sarcomere that inhibits contraction by preventing actin-myosin interaction. Pathogenic TNNI3 variants can cause both hypertrophic and restrictive cardiomyopathies but lack targeted therapies. We identified a family with restrictive cardiomyopathy carrying a cTnI variant at amino acid 157 (A157V). Using CRISPR-Cas9, we generated a knock-in mouse model reflecting this mutation (A158V in mouse). Our previous studies showed that homozygous A158V mice had impaired cardiac relaxation on invasive hemodynamics but normal lifespan, no echocardiographic changes, and no fibrosis. Hypothesis: Myofibril mechanics and transcriptomic studies will better discriminate TNNI3 A158V mice from WT than previous phenotyping studies. Methods: Heart tissue was obtained from wild-type (WT) and homozygous A158V mice at 9-10 months. Myofibrils were isolated from heart tissues and mechanical measurements were completed using the fast solution switching method. RNA was extracted for bulk RNA sequencing. Results: Isolated myofibril studies showed significant prolongation of the linear relaxation phase in A158V mice versus controls (p=0.02) but no significant differences in active tension. Unsupervised clustering of bulk RNA samples separated A158V samples from controls, with 44% transcriptional variation derived from genotype. Cardiac changes in the A158V model were confirmed by significant depletion of pathways involved in structural components of the contractile apparatus, including contractile fiber, sarcomere, and I-Band. On an individual gene level, A158V mutated mice displayed higher expression of cardiac remodeling genes such as Timp1 , Postn , and Tnc . Conclusion: The TNNI3 A158V variant consistently produces impaired relaxation with myofibril studies showing prolonged linear relaxation phase. Transcriptomic studies highlight distinct clustering of TNNI3 A158V mice from WT, with prominent depletion in contractile apparatus pathways. Our findings suggest traditional methods to characterize mouse models may fail to capture disease phenotype in cardiomyopathies; however, myofibril studies and transcriptomic profiling may reveal earlier phenotypic changes.

Fast and light-efficient wavefront shaping with a MEMS phase-only light modulator

Over the last two decades, spatial light modulators (SLMs) have revolutionized our ability to shape optical fields. They grant independent dynamic control over thousands of degrees-of-freedom within a single light beam. In this work we test a new type of SLM, known as a phase-only light modulator (PLM), that blends the high efficiency of liquid crystal SLMs with the fast switching rates of binary digital micro-mirror devices (DMDs). A PLM has a 2D mega-pixel array of micro-mirrors. The vertical height of each micro-mirror can be independently adjusted with 4-bit precision. Here we provide a concise tutorial on the operation and calibration of a PLM. We demonstrate arbitrary pattern projection, aberration correction, and control of light transport through complex media. We show high-speed wavefront shaping through a multimode optical fiber – scanning over 2000 points at 1.44 kHz. We make available our custom high-speed PLM control software library developed in C++. As PLMs are based upon micro-electromechanical system (MEMS) technology, they are polarization agnostic, and possess fundamental switching rate limitations equivalent to that of DMDs – with operation at up to 10 kHz anticipated in the near future. We expect PLMs will find high-speed light shaping applications across a range of fields including adaptive optics, microscopy, optogenetics and quantum optics.

Tuning properties of binary functionalization of Sc2C MXenes for supercapacitor electrodes

Surface functionalization of two-dimensional (2D) materials like Sc2C MXenes offers a promising avenue for tailoring their properties for various applications. At the same time, significant research has focused on pure terminations involving oxygen (-O), fluorine (-F), or hydroxyl (-OH) groups. Binary surface functionalization still needs to be explored. Our work addresses this gap by investigating binary functionalized Sc2C monolayers, specifically Sc2CFN and Sc2COS. Using first-principles calculations, we explore the structural, electronic, and quantum capacitance (CQ) properties of pristine Sc2C and functionalized Sc2CFN and Sc2COS. The CQ measurements reveal distinctive electronic behaviour, with Sc2CFN and Sc2COS exhibiting indirect bandgaps of 0.90 and 1.48 eV, respectively. Introducing functional groups induces a metal-to-semiconductor transition, enhancing charge storage at the cathode and increasing the CQ to 371.64 and 341.23 μF/cm2 for Sc2CFN and Sc2COS, respectively. As far as energy applications are concerned, we also calculate the Shockley-Queisser (SQ) efficiency, which is a widely accepted quantity to get an estimate of the photovoltaic efficiency of 28.77 % for Sc2CFN and 32.97 % for Sc2COS materials. Additionally, we analyze the current-voltage (IV) characteristics, uncovering negative differential conductance (NDC) effects in Sc2COS, indicative of its potential for fast molecular switching applications. Our study provides valuable insights into the properties of binary functionalized Sc2C MXenes, paving the way for their utilization in energy storage and nanoelectronic devices.

Tunable photo-response in the visible to NIR spectrum range of Germanium-based junctionless nanowire transistor

In this paper, the phototransistor behavior is investigated in the germanium-on-insulator (GeOI)-based junctionless nanowire (JL-NW) transistor under various light conditions. High responsivity and photosensitivity are attributed in the fully depleted regime within the visible and near-infrared bands. The impact of light is also investigated in detail on the electronic and transfer characteristics such as energy bandgap, carrier distribution, electrostatic potential, electric field, generation and recombination rates. Further, the channel doping and thickness are tuned to optimize the optical responsivity. The significant tunability of responsivity is observed with increasing channel thickness. The device exhibits fast optical switching performance, which is further enhanced at higher input light power. Overall, at the nanoscale dimension, our proposed phototransistor demonstrates better detectivity with a significantly smaller illumination area. Thus, the GeOI-based JL-NW phototransistors can be used for imaging (visible wavelength range) and bioimaging (near-infrared wavelength range) applications in advanced technology nodes.

Enhancing versatility and adaptability in soft robotics: design and analysis of an adaptive gripping port

Abstract Currently, soft robots demonstrate the considerable promise for various applications. However, soft actuators tend to be damaged more easily compared to rigid mechanical components. The common practice of replacing soft actuators typically requires manual intervention and a longer duration. In this paper, we design an adaptive gripping port (AGP) for soft robotic interactions, which is used for fast switching and connectivity. Through a combination of theoretical modeling, fabrication, and experimental analysis, its gripping, releasing, and sealing capabilities are demonstrated. We present four types of the AGP with different internal bladder structures, demonstrating maximal enhancements in griping capability and sealing performance of up to 50% and 40%, respectively. Experiments show the AGP’s adaptability to connectors of various sizes, accommodating diameters from 0 mm to 15.76 mm under negative pressure driving. The relationship between gripping force, maximum sealing pressure, connector diameter, and driving pressure is studied. We also exhibit collaborations with a circular gripper and soft grippers incorporating the AGP to verify the possibility of their interactions.

Dual Energy Metal Artifact Reduction for Iodine-125 Seed Identification in Postimplant CT after Prostate Brachytherapy.

To assess the metal artifact reductions of dual-energy computed tomography (DECT) high-energy virtual monochromatic images (VMI) combined with the single energy metal artifact reduction (SEMER) (CANON MEDICAL SYSTEMS, Otawara, Japan) processing techniques for iodine (I)-125 seed identification in postimplant computed tomography (CT) after prostate brachytherapy. Dual-energy acquisition with fast tube voltage switching was performed on a prostate phantom with simulated seeds and six clinical cases treated with I-125 prostate brachytherapy. The images were retrospectively reconstructed at VMI energy levels of 65-200 keV and with and without SEMAR (SEMAR and non-SEMAR images). To estimate seed swelling, the caliber of iodine-125 seed was calculated as the full width at half maximum. The metal artifacts were evaluated using the artifact index (AI). The dose distributions were calculated and were compared among the high-energy VMI (SEMAR and non-SEMAR images) and low-energy VMI (SEMAR images). The blooming artifacts decreased at higher energy levels. In addition, the SEMAR process markedly reduced AI, which helped reduce overestimation of high dose ranges in the treatment planning dose map. The locations and number of iodine-125 seed were clearly identified in the dose distribution map of the treatment planning using 200keV VMI with SEMAR. The high-energy VMI of the dual energy CT in combination with SEMAR is appropriate for the postimplant planning process of I-125 prostate brachytherapy.

Influence of fast switching fault current limiter on electromagnetic transient of extra-high voltage transmission line

Abstract The rapid advancement of power systems has led to an increase in short-circuit currents. The short-circuit current can be effectively limited by adding a fast-switching fault current limiter. However, incorporating a current-limiting reactor into ultra-high voltage lines may impact electromagnetic transients. This study utilizes PSCAD/EMTDC electromagnetic transient simulation software to develop a typical 330kV transmission line model for simulation analysis. The paper aims to study whether the current limiting reactor will affect the switching overvoltage in the automatic reclosing overvoltage. The results show that the input of the current-restricting transformer efficiently constrains the magnitude of short-circuit currents and exerts minimal influence on the automatic reclosing overvoltage in ultra-high voltage transmission lines.

Spatially resolved random telegraph fluctuations of a single trap at the Si/SiO2 interface

We use electrostatic force microscopy to spatially resolve random telegraph noise at the Si/SiO2 interface. Our measurements demonstrate that two-state fluctuations are localized at interfacial traps, with bias-dependent rates and amplitudes. These two-level systems lead to correlated carrier number and mobility fluctuations with a range of characteristic timescales; taken together as an ensemble, they give rise to a [Formula: see text] power spectral trend. Such individual defect fluctuations at the Si/SiO2 interface impair the performance and reliability of nanoscale semiconductor devices and will be a significant source of noise in semiconductor-based quantum sensors and computers. The fluctuations measured here are associated with a four-fold competition of rates, including slow two-state switching on the order of seconds and, in one state, fast switching on the order of nanoseconds which is associated with energy loss.

A low-cost strategy for systematically removing DC short-circuit currents in AC/DC-HDN

For any practically applied AC/DC hybrid distribution network (AC/DC-HDN), the hard issue of removing DC short-circuit currents must be solved by a cost-effective scheme. However, up to now, in the most published achievements of AC/DC-HDN, the systematic scheme to address the above issue is rarely found. This paper proposes a novel strategy with a low cost for solving this problem. The proposed strategy can: (i) greatly decrease the DC short-circuit current components flowing from the AC/DC converters to the fault point, (ii) fast switch off the paths of DC short-circuit current components from DG branches to the fault point, (iii) completely block the DC short-circuit current components that feed into the fault point from the capacitors paralleled on the DC ports of load branches. Also, in this paper, a new topology of DC/DC converter with a controlled zero-current output function is proposed for fast switching off the paths of DC short-circuit current components from DG branches to the fault point. The scheme of relay protection and automatic control matching with the proposed strategy is designed. The principles of the scheme and design are explained in detail. The simulation results verified the effectiveness of the proposed strategy are given.

Study on electro-optical dual-control color-changing and energy-storage device based on Mo-WO3 and Al-TiO2 thin film electrode

Under optical and electrical control, a multifunctional electro-optical dual-control color-changing and energy-storage device not only realizes quick color conversion, but also achieves good storage performance. In this work, Mo doped WO3 (Mo-WO3) films were synthesized through one-step hydrothermal method and N719/Al doped TiO2 (N719/Al-TiO2) films were synthesized by hydrothermal and dip-dyeing method. Eventually, choosing Mo-WO3 as cathode and N719/Al-TiO2 film as anode, a multifunctional electro-optical dual-control Mo-WO3@N719/Al-TiO2 color-changing and energy-storage device was constructed. Under electrical control, the device shows excellent coloration efficiency (73.99 cm2/C), fast color switching rate (coloring/ bleaching time is 3.6 s/1.4 s), obviously improved area capacitance (about 82.6 mF/cm2) and excellent cycle stability. Under optical control, the device also shows shortened response time (coloring/ bleaching is 64.3 s/143.4 s), outstanding coloration efficiency (70.49 cm2/C), better area capacitance (about 58.6 mF/cm2) and excellent photoelectric conversion efficiency (10.56 %).

Bridging to Commercialization: Record-Breaking of Ultra-Large and Superior Cyclic Stability Tungsten Oxide Electrochromic Smart Window.

Electrochromic smart windows (ESWs) can significantly reduce energy consumption in buildings, but their cost-effective, large-scale production remains a challenge. In this study, the instability of black phosphorus is leveraged to induce the growth of the tungsten oxide film through its decomposition process, inspired by the 2D material-assisted in situ growth (TAIG) method. This approach results in the preparation of large-scale, high-performance WO3-x·nH2O (n<2) films. Characterization techniques and DFT calculations confirm efficient regulation ofstructural water and oxygen vacancies during TAIG preparation. The WO3-x·nH2O films exhibit excellent electrochromic (EC) properties, including high transmittance modulation (74.2%@1100nm), fast switching time (tc=5.5s, tb=3.8s), high coloration efficiency (124.7cm2C-1), and superior cyclic stability (transmittance modulation retained 94.7% after 20000 cycles). Ultra-largeWO3-x·nH2O film are prepared via a simple immersion process, and fabricated into a large-area ESW under facile laboratory conditions, demonstrating the economic and practical feasibility of this approach in industrial-scale production. Operated by the intelligent control circuit, the ESWexhibits remarkable EC properties and cyclic stability This research represents a milestone in improving the performance and industrial-scale production of ESWs, bridging the gap to the commercialization of EC technology.

Experimental Performance Analysis of Fabricated Si/Ge Thin Film Structure

This paper is devoted to the evaluation of a Silicon/Germanium (Si/Ge) thin film structure based on experimental measurements. An electron beam evaporator was used to fabricatethis structure. The sample was prepared under high vacuum conditions (pressure of 10-5 Torr, power of 6 kV and current of 200 mA). At these conditions, it was possible to get films with thickness of approximately 300 Å. The capacitance–voltage (C–V) and current–voltage (I–V) measurements of the sample were performed by a staircase sweep of voltages from 0 to 5 V and back from 5 to 0 V at room temperature. The sample exhibits a low hysteresis in measurements; this hysteresis is gradually removed when the sample is exposed to temperatures until 80 °C using a Carbolite Oven. It is also observed that both C-V and I-V characteristic curves of the sample has been smoothened. This sample exhibits an electroforming behavior as a metal-oxide-semiconductor (MOS) device over a short time duration of the selected staircase double sweep, hence it can be exploited as a fast switching element in digital microelectronic circuits. In addition, the hysteresis changes over the range from room temperature until 80 °C have opened the door to the possibility of exploiting this sample as a proximity temperature sensor within that range of temperature.