Rapid Switching Research Articles

High-performance photon-driven DC motor system

Direct current (DC) motors are crucial in drones, robotics, and electrical devices. Conventionally, the DC motor is driven by a switching electricity converter, which utilizes electrical energy to drive mechanical motion. However, the rapid on-off switching actions in the switching electricity converter would cause electromagnetic interference (EMI), impairing the functionality of drive systems. Here, we propose a photon-driven DC motor system based on photonic converter, which utilizes optical energy to drive mechanical motion, and therefore avoids EMI derived from electrical switching and immunizes against EMI during electrical energy transmission in conventional switching electricity-driven DC motor system. The operation principle and power modulation-based speed control are also presented for the proposed photon-driven DC motor system. The experiments demonstrate that the motor accurately follows the speed reference and withstands load disturbances. This innovation opens new potential for DC motor applications by improving electromagnetic compatibility.

A 2DEG‐Based GaN‐on‐Si Terahertz Modulator with Multi‐Mode Switchable Control

AbstractAs terahertz (THz) technology has been widely considered as a key candidate for future sixth‐generation wireless communication networks, THz modulators show profound significance in wireless communication, data storage, and imaging. In special, dynamic tuning of THz waves through 2D electron gas (2DEG) incorporated with a hybrid design of metasurface has attracted keen interest due to the combined merits of deliberate structural design, rapid switching speed and the process compatibility. Current meta‐modulator enables very high modulation depth but encounter limited bandwidth. In this paper, by taking into account the co‐functional effects of temperature and voltage‐dependent dynamic control on transmission amplitude, a 2DEG‐based GaN‐on‐Si modulator with two switchable operational states (or four modes) of active wave control is proposed. Under cryogenic temperature conditions, the proposed device exhibits prominent 2D plasmons characteristics with switchable transitions between the gated mode and ungated mode for active control. Under room temperature conditions, the proposed device exhibits non‐resonance broadband spectra characteristics with tunable transitions between the linearity mode and depletion mode for transmission control. The scheme provides an option for the development of the actively tunable THz meta‐modulator and paves a way for the robust multifunctionality of electrically controllable THz switching, and biosensors.

A Dual Column pH Switchable Water Stationary Phase System for Separation Control in Supercritical Fluid Chromatography.

A dual column system comprised of a pH switchable water stationary phase column and a conventional non-polar capillary column is introduced for use in Supercritical Fluid Chromatography (SFC). By removing or adding NH4OH to the system hydration source, the water stationary phase pH can be rapidly switched between acidic (measured at pH∼3) and basic (measured at pH∼9) in seconds, while the operating character of the conventional column is unchanged. This switch modulates the velocity of ionizable analytes about 20-fold in the system, whereas non-ionizable analytes are not affected. In this way, the retention time of acids and/or bases can be reproducibly altered (<1% RSD; n = 3) in SFC separations. As a result, analyte selectivity and resolution can be readily controlled during analyses. For example, a selectivity reversal (alpha from 0.4 to 1.6) and a resolution increase (from 0 to 13) are demonstrated. Rapid stationary phase pH switching also allows multiple acids, bases, and/or neutral analytes to be determined simultaneously. Applications demonstrate that this method can greatly simplify complex mixture analysis in SFC by helping to separate target analytes from interfering matrix components.

Prophages divert Staphylococcus aureus defenses against host lipids

Phages are ubiquitous in bacteria, including clinical Staphylococcus aureus, where Sfi 21/Sa3 phages often integrate into the hlb gene, which encodes Hlb sphingomyelinase. This integration acts as a rapid regulatory switch for Hlb production. Our findings suggest that Sfi 21/Sa3 prophages and Hlb activity influence S. aureus fitness by modulating the incorporation of the toxic linoleic acid (C18:2) from serum into the bacterial membrane. This process relies on C18:2 derived from 1,3-diglyceride, facilitated by the FakB1 kinase subunit. Palmitic acid (C16), primarily released from serum through Hlb activity, competes with C18:2 for FakB1. This mechanism contributes to adaptation to AFN-1252, an antibiotic inhibiting the fatty acid synthesis pathway (anti-FASII). Since S. aureus relies on exogenous fatty acids for growth, AFN-1252 treatment leads to increased proportion of C18:2 in the membrane. Furthermore, Hlb inhibition, whether by prophage insertion, gene inactivation, or enzyme inhibition, delays S. aureus adaptation, resulting in a higher proportion of C18:2 in the membrane. This study sheds light on the role of lipid environments in infections and may contribute to the accurate prediction of infection risks and therapeutic efficacy. Moreover, since both anti-FASII agent and Hlb inhibitor enhance C18:2 incorporation, they represent potential candidates for combined strategies against S. aureus.

In situ synthesis and structural morphology analysis of 3D porous hierarchical V2O5 films for transmissive-to-black all-solid-state electrochromic devices

3D, porous, low-dimensional, and nanostructured V2O5 films have significant potential for application in ECDs, but their development is still in its nascency. This paper reports a facile strategy of using PEG as a structure-directing agent and short-time heat treatments to obtain 3D, porous, and hierarchical V2O5 films comprising interpenetrating stacked ultra-long nanowire surfaces and nanorod/nanosheet mixed interiors deposited on ITO-glass substrates. The mechanism of morphological transformation was studied in detail, and the analysis shows that the formation of such special structured films is a synergetic result of the guided intercalation of PEG, atomic rearrangement, Ostwald ripening, anisotropy of crystal growth, and orientation attachment mechanism. Among them, the preferred PEG addition amount of 25 % for the 350-3-V2O5 film was applied in two types of all-solid-state ECDs: one using a gel quasi-solid electrolyte and the other using a solid-film electrolyte. The 350-3-V2O5 film served as an ion storage coating and WO3 was the electrochromic layer. These devices achieved ideal reversible switching of transmissive-to-black electrochromic characteristics. Notably, the ‘Integrated-Type’ ECD, composed of inorganic all-solid-state films, has a large optical modulation range ΔT = 72.0 %, rapid switching responses (colouration 25.4 s and bleaching 20.8 s), and sustained electrochromic performance.

Large-range dynamic characteristic adjustment of high-speed on-off valve for water hydraulic manipulators based on multistage voltage and double sliding mode control

High-speed on–off valves (HSVs) are highly adaptable and can control proportional flow, making them ideal for water hydraulic manipulators. In this paper, a water hydraulic HSV is specifically designed for water hydraulic manipulators. To enhance the dynamic characteristics of the HSV, a multistage voltage control combined with double sliding mode control (MVSMC) is proposed. A control system based on an H-bridge circuit is designed to implement the MVSMC algorithm. Simulations and experiments are conducted to evaluate the HSV’s rapid switching and adjustment of dynamic characteristics. The MVSMC algorithm enables quick switching of the HSV, even under fluctuating driving voltages in simulations. The sliding mode controller can control the dynamic characteristics of the HSV over a wide range by adjusting the pre-opening current and holding current. Experimental results show that, driven by the MVSMC algorithm, the opening time and closing time of the HSV are only 1.2 ms and 1.4 ms, respectively. The total non-adjustable opening time and closing time of the HSV are 0–1.2 ms and 0–1.4 ms, respectively. In other ranges, the switching time of the HSV is adjustable. Compared to conventional pulse width modulation (CPWM) control, the MVSMC algorithm offers extreme switching speed for the HSV. The MVSMC algorithm can adjust the dynamic characteristics of the HSV in a wide range, making it suitable for various working conditions requiring different dynamic characteristics.

Stability and sensitivity of interacting fermionic superfluids to quenched disorder

The microscopic pair structure of superfluids has profound consequences on their properties. Delocalized pairs are predicted to be less affected by static disorder than localized pairs. Ultracold gases allow tuning the pair size via interactions, where for resonant interaction superfluids show largest critical velocity, i.e., stability against perturbations. The sensitivity of such fluids to strong, time-dependent disorder is less explored. Here, we investigate ultracold, interacting Fermi gases across various interaction regimes after rapid switching optical disorder potentials. We record the ability for quantum hydrodynamic expansion of the gas to quantify its long-range phase coherence. Contrary to static expectations, the Bose-Einstein condensate (BEC) exhibits significant resilience against disorder quenches, while the resonantly interacting Fermi gas permanently loses quantum hydrodynamics. Our findings suggest an additional absorption channel perturbing the resonantly interacting gas as pairs can be directly affected by the disorder quench.

Development of a rapid magnetic relaxation switching aptasensor for detection of saxitoxin using Fe3+/silver nanoparticles reaction system

Saxitoxin (STX) is a highly toxic marine bio-toxin, which has attracted great attention in the field of environmental and food safety. It is of crucial importance to develop efficient, sensitive and cost-effective methods for detecting STX. Here, we designed a magnetic relaxation switching (MRS) aptasensor for detection of STX based on FeCl3-regulated the aptamer-functionalized silver nanoparticles-coated magnetic nanoparticles (MNP@Ag NPs). In the light of the sensing effect of transverse relaxation time (T2) for optimizing, the etched time, the concentration of MNP@Ag NPs, the concentration of aptamers and incubation time were 15 min, 4 mg mL−1, 0.4 μM and 90 min, respectively. The MRS aptasensor showed good linearity amidst the sensing range of 0.2 μM to 1.0 μM and the limit of detection (LOD, S/N = 3) of 0.18 μM. Additionally, the MRS aptasensor demonstrated excellent sensitivity, reproducibility, and stability in clams and mantis shrimps. The recovery of STX ranged from 82.6 % to 101.5 % with low relative standard deviation (RSD) values, suggesting its effectiveness for detecting STX across a wide array of seafood samples.

The Interplay of Core Diameter and Diameter Ratio on the Magnetic Properties of Bistable Glass-Coated Microwires

Glass-coated microwires exhibiting magnetic bistability have garnered significant attention as promising wireless sensing elements, primarily due to their rapid magnetization switching capabilities. These microwires consist of a metallic core with diameter d, encased in a glass coating, with a total diameter D. In this study, we investigated how the dimensions of both components and their ratio (d/D) influence the magnetization reversal behavior of Fe-based microwires. While previous studies have focused on either d or d/D individually, our research uniquely considered the combined effect of both parameters to provide a comprehensive understanding of their impact on magnetic properties. The metallic core diameter d varied from 10 to 19 µm and the d/D ratio was in the range of 0.48–0.68. To assess the magnetic properties of these microwires, including the shape of the hysteresis loop, coercivity, remanent magnetization, and the critical length of bistability, we employed vibrating sample magnetometry in conjunction with FORC-analysis. Additionally, to determine the critical length of bistability, magnetic measurements were conducted on microwires with various lengths, ranging from 1.5 cm down to 0.05 cm. Our findings reveal that coercivity is primarily dependent on the d/D parameter. These observations are effectively explained through an analysis that considers the competition between magnetostatic and magnetoelastic anisotropy energies. This comprehensive study paves the way for the tailored design of glass-coated microwires for diverse wireless sensing applications.

Variable-energy cocktail beam technology for investigating synergistic damage in nuclear materials on LEAF platform

This study addresses the critical issue of synergistic radiation damage in structural materials of fusion reactors, focusing on the interaction between the displacement defects and transmutation-produced hydrogen and helium. These effects are simulated and investigated by employing the advanced multi-beam ion implantation capabilities of the LEAF (Low Energy high intensity highly charged ion Accelerator Facility) platform. Firstly, high-intensity cocktail beams, such as “4He+ and 56Fe14+" and “4He+ and 58Ni15+", are generated and characterized successfully. Then, a complex radiation environment is mimicked within the fusion reactors by applying variable-energy irradiation. Secondly, similar penetration depths for different ions, which are crucial for studying synergistic effects, are obtained by precisely controlling the energy of the cocktail beams through the innovative energy modulation system of the LEAF platform. Finally, the post-irradiation analyses, performed by using the transmission electron microscopy (TEM) and nanoindentation, revealed distinct microstructural changes and alterations in material properties, providing insights into the degradation mechanisms under irradiation. This work not only generates diverse and high-intensity “cocktail” ion beams but also achieves rapid energy switching of the beams. Further, the work is expected to pave the way for the implementation of a novel multi-beam irradiation technique in advanced heavy-ion linear accelerators, and also to provide innovative experimental methods and technical support for studying the synergistic effects of nuclear materials.

High-speed Ta2O5-based threshold switching memristor for LIF neurons

Due to their high similarity to biological ion channels, low power consumption, small footprint, and the fact that they do not require reset circuits, threshold switching memristors have been intensively studied for simulating neurons in neuromorphic chips. Switching speed is one of the key challenges which limit the application of threshold switching memristors in chips. In this study, Ta2O5 threshold switching memristors with high switching speeds were prepared by doping with silver. The results show that 14 wt. % Ag doped Ta2O5 threshold switching memristors exhibit excellent bi-directional threshold switching performance, featuring fast switching speeds (&amp;lt;20 ns, &amp;lt;18 ns), low leakage currents (&amp;lt;10 pA), and high switching ratio (&amp;gt;107). According to the field nucleation theory, the rapid switching speed can be attributed to the low nucleation energy (0.26 eV) of silver within the Ta2O5 matrix, which is achieved by incorporating 14 wt. % Ag during the doping process. Based on Pspice, a LIF (leaky integrate-and-fire) neuron based on the silver nanoparticles doped Ta2O5 threshold switching memristors is built, and its firing function has been simulated. The results show that the LIF neuron with a short switching time is able to excite pulse spiking with high frequencies. These results demonstrated that the silver nanoparticles doped Ta2O5-based threshold switching memristors hold significant potential for constructing high-speed artificial neural networks.

Investigating the Performance Optimization of Three‐Quantum‐Well High Electron Mobility Transistor Device: Analyzing Operational Characteristics and Gate Voltage Influence

Quantum well AlGaN/AlN/GaN high electron mobility transistor (HEMT) devices are a unique kind of semiconductor device that make use of a heterostructure made up of layers of different materials. In this study, the operational characteristics and performance optimization of HEMT devices, with a specific emphasis on the behavior of three‐quantum‐well (3QW) HEMT devices, are explored. The impact of gate voltage is explored and is observed that higher gate voltages result in lower pinch‐off voltages and higher saturation drain currents. In these findings, valuable insights for optimizing circuit designs and ensuring dependable operation across a range of electronic applications are offered. In addition, In this study, the device's ability to detect changes in gate voltage and its nonlinear characteristics is emphasized, providing valuable information for improving the device's performance. Additionally, the benefits of HEMT devices with negative threshold voltages are explored. Devices utilizing AlGaN/AlN/GaN structures demonstrate exceptional performance characteristics, such as rapid switching capabilities, high energy efficiency, and low noise performance, making them well suited for a wide range of scientific and technological applications. Finally, when comparing a QW HEMT device at different drain bias conditions (Vd = 1 V and Vd = 5 V), noticeable variations suggesting improved performance with higher drain bias.

Programmable multi-wavelength distributed feedback laser array integrated in a liquid crystal polymer waveguide.

Liquid crystal (LC) distributed feedback (DFB) lasers hold significant potential for integrated photonics applications. However, limitations in wavelength spacing for wavelength switching, device size, and compatibility with other technologies have impeded advancements of the LC DFB laser in integration and responsiveness. Herein, we propose a thin-film multi-wavelength DFB laser array utilizing high-resolution patterned programmable nematic LC polymers, enabling rapid switching with high-resolution wavelength spacing between wavelength division multiplexing channels while maintaining a stable single longitudinal mode (SLM) for each laser. The underlying physical mechanism involves modulating the effective refractive index of the DFB laser by varying the LC molecules' orientation angles between adjacent regions of the LC grating to achieve wavelength modulation. Additionally, a specialized LC waveguide design connects the DFB lasers, facilitating wavelength modulation as well as straight-line and bending propagation of the laser. Furthermore, the laser array demonstrates a relatively low energy threshold, facilitating its applications in high-integration scenarios.

Fast-switching electrochromic smart windows based on WO3 doped NiO thin films

Nickel oxide (NiO) is a very promising material for the counter electrode in electrochromic devices (ECDs). In the current research, WO3 incorporated NiO thin films were fabricated via RF sputtering to enhance the electrochromic performance of NiO thin films. An XRD analysis revealed that the addition of WO3 to the cubic NiO thin film disrupts its long-range crystalline structure, resulting in an amorphous state. FESEM revealed the formation of columnar structure which favours ECDs. XPS analysis revealed that the addition of WO3 into NiO enhanced the hole concentration by creating nickel vacancies (nickel defects). Compared to pristine NiO, WO3 mixed NiO thin films showed enhanced optical modulation (66 %) with rapid switching speed (0.6 s/1.0 s for bleaching/colouring). This is mainly because the defect- induced amorphous structure of the nickel tungsten oxide thin film can provide large number of diffusion channels which facilitates the rapid ion intercalation process, and can accommodate large number of ions, and hence enhances the electrochromic performance. This advancement might have a substantial impact on the development of nickel tungsten oxide as a potential counter electrode in high-performance energy saving smart windows.

Optimization of MOSFET Copper Clip to Enhance Thermal Management Using Kriging Surrogate Model and Genetic Algorithm

Metal–oxide–semiconductor field-effect transistors (MOSFETs) are critical in power electronic modules due to their high-power density and rapid switching capabilities. Therefore, effective thermal management is crucial for ensuring reliability and superior performance. This study used finite element analysis (FEA) to evaluate the electro-thermal behavior of MOSFETs with copper clip bonding, showing a significant improvement over aluminum wire bonding. The aluminum wire model reached a maximum temperature of 102.8 °C, while the copper clip reduced this to 74.6 °C. To further optimize the thermal performance, Latin Hypercube Sampling (LHS) generated diverse design points. The FEA results were used to select the Kriging regression model, chosen for its superior accuracy (MSE = 0.036, R2 = 0.997, adjusted R2 = 0.997). The Kriging model was integrated with a Genetic Algorithm (GA), further reducing the maximum temperature to 71.5 °C, a 4.20% improvement over the original copper clip design and a 43.8% reduction compared to aluminum wire bonding. This integration of Kriging and the GA to the MOSFET copper clip package led to a significant improvement in the heat dissipation and overall thermal performance of the MOSFET package, while also reducing the computational power requirements, providing a reliable and efficient solution for the optimization of MOSFET copper clip packages.

Profound primary prevention of liver cancer following a natural experiment in China: A 50‐year perspective and public health implications

AbstractLiver cancer causes upwards of 1 million cancer deaths annually and is projected to rise by at least 55% over the next 15 years. Two of the major risk factors contributing to liver cancer have been well documented by multiple epidemiologic studies and the hepatitis B virus (HBV) and aflatoxin show a synergy that increases by more than 8‐fold the risk of liver cancer relative to HBV alone. Using the population‐based cancer registry established by the Qidong Liver Cancer Institute in 1972 and aflatoxin‐specific biomarkers, we document that reduction of aflatoxin exposure has likely contributed to a nearly 70% decline in age‐standardized liver cancer incidence over the past 30 years despite an unchanging prevalence of HBV infection in cases. A natural experiment of economic reform in the 1980s drove a rapid switch from consumption of heavily contaminated corn to minimally, if any, contaminated rice and subsequent dietary diversity. Aflatoxin consumption appears to accelerate the time to liver cancer diagnosis; lowering exposure to this carcinogen adds years of life before a cancer diagnosis. Thus, in 1990 the median age of diagnosis was 48 years, while increasing to 67 years by 2021. These findings have important translational public health implications since up to 5 billion people worldwide might be routinely exposed to dietary aflatoxin, especially in societies using corn as the staple food. Interventions against aflatoxin are an achievable outcome leading to a reduction in liver cancer incidence and years of delay of its nearly always fatal diagnosis.

Programmable multi-stability of curved-crease origami structures with travelling folds

Multi-stable structures capable of rapid switching among different stable states have seen applications in various fields such as energy absorption, mechanical computing, and soft actuators. Curved-crease origami, which naturally involves simultaneous deformation of creases and facets, shows great potential in the development of multi-stable structures. However, upon loading, existing curved-crease origami structures tend to follow the same deformation mode as in the curved surface formation process which involves facets elastic bending, flattening, and reverse bending, thus leading to only two stable states. To achieve multi-stability, here we propose a series of curved-crease origami structures composed of planar facets and curved ones. Through a combination of experiments, numerical simulations, and analytical modelling, we demonstrate that the planar facets forming a Sarrus linkage guide the deformation mode of the curved ones, leading to the initiation and propagation of travelling folds in the curved facets. By transforming the travelling folds at specific positions into actual creases, we can achieve multiple stable states in a single structure. In addition, the number and positions of the stable states, as well as the initial peak force, can be programmed by varying the geometric parameters. Consequently, this work opens a new pathway for the development of generic multi-stable structures with programmable mechanical properties.

A versatile bioluminescent probe with tunable color.

Bioluminescence is a powerful method for imaging in vivo, but applications at the microscale are far from routine. This is due, in part, to a lack of versatile tools for visualizing dynamic events. To address this void, we developed a new platform-Bioluminescence Resonance Energy mAKe over with a Fluorescence-Activating absorption-Shifting Tag (BREAKFAST). BREAKFAST features a bright luciferase combined with a chemogenetic tag (pFAST) for rapid color switching. In the presence of luciferin and a discrete fluorogenic ligand, signal is observed via resonance energy transfer. We evaluated spectral outputs with various fluorogens and established the utility of BREAKFAST for combined fluorescence and bioluminescence imaging. Dynamic, four-color visualization was achieved with sequential ligand addition and spectral phasor analysis. We further showed selective signal quenching with a dark fluorogen. Collectively, this work establishes a new method for bioluminescence imaging at the cellular scale and sets the stage for continued probe development.

Rapid prey switching of juvenile snapper (Chrysophrys auratus) in response to fluctuating visibility

ABSTRACT This study investigates the feeding behaviour of juvenile (0+) snapper (Chrysophrys auratus) in an estuarine nursery habitat. Underwater video footage recorded across a range of tidal states and times of day revealed a shift in foraging mode that was strongly related to water clarity. Fish exclusively ate benthic prey when horizontal water visibility was <4 m, but plankton dominated their diet in clearer water. The percentage of plankton in the diet also decreased later in the day, and on the outgoing tide. To our knowledge, this is the first documented evidence of daily prey-switching behaviour in wild juvenile snapper in New Zealand. Our findings highlight the adaptive foraging strategies of juvenile snapper as well as the potential ecological impacts resulting from anthropogenic alterations in water quality, which likely affect many marine species.

3D bioprinting technology and equipment based on microvalve control.

3D bioprinting technology is widely used in biomedical fields such as tissue regeneration and constructing pathological model. The prevailing printing technique is extrusion-based bioprinting. In this printing method, the bioink needs to meet both printability and functionality, which are often conflicting requirements. Therefore, this study has developed an innovative microvalve-based equipment, incorporating components such as pressure control, a three-dimensional motion platform, and microvalve. Here, we present a droplet-based method for constructing complex three-dimensional structures. By leveraging the rapid switching characteristics of the microvalve, this equipment can achieve precise printing of bio-materials with viscosities as low as 10mPa·s, significantly expanding the biofabrication window for bioinks. This technology is of great significance for 3D bioprinting in tissue engineering and lays a solid foundation for the construction of complex artificial organ tissues.