Fast Response Research Articles

Ultralow Voltage High-Performance Nanocellulose-Based Electro-Ionic Actuators for Soft Robots.

High-performance eco-friendly soft actuators showing large displacement, fast response, and long-term operational capability require further development for next-generation bioinspired soft robots. Herein, we report an electro-ionic soft actuator based on carboxylated cellulose nanocrystals (CCNC) and carboxylated cellulose nanofibers (CCNF), graphene nanoplatelets (GN), and ionic liquid (IL). The actuator exhibited exceptional actuation performances, achieving large displacements ranging from 1.6 to 12.3 mm under ultralow actuation voltages of 0.25-1.5 V. It also operated stably across a broad frequency band from 0.1 to 10 Hz and displayed a significant working stability of 99.3% after up to 240 cycles. Remarkably, the electro-active actuator demonstrated a fast response (0.39 s delay under 1.0 V at 0.1 Hz), and a long lifespan (with only a minor decrease of 2% for 2 years). The enhanced actuation performances of the actuator were attributed to its superior ionic conductivity, high charge storage ability, strong ionic interaction, and physical-chemical cross-linked networks. Furthermore, we successfully demonstrated the bioinspired applications of CCNC/CCNF-IL-GN actuators including micro-grippers, spiral-structure electroactive stents, biomimetic fingers, and bionic dragonfly wings. The proposed actuator and its bioinspired robot designs could offer a significant way for the development of next-generation eco-friendly soft actuators, soft robots, and biomedical microdevices in microenvironments requiring low-voltage environment.

Improving Room Temperature Formaldehyde Sensitivity with Samarium-Doped Titanium Dioxide

Abstract Samarium (Sm)-doped titanium dioxide (TiO₂) thin films were synthesized using the spray pyrolysis technique at 400°C, with Sm doping concentrations of 0, 2, 4, and 6 Wt.% to enhance structural, optical, morphological, and gas-sensing properties. The films, deposited on ultrasonically cleaned glass substrates, were characterized using X-ray diffraction , scanning electron microscopy, atomic force microscopy (AFM), and UV-Vis spectroscopy. Structural analysis revealed improved crystallinity and uniform surface morphology with Sm doping, while AFM indicated increased surface roughness, promoting gas adsorption. UV-Vis analysis showed a reduced energy bandgap, enhancing visible light absorption and gas-sensing performance. Gas sensing evaluations demonstrated high sensitivity to formaldehyde, with notable selectivity over ethanol, toluene, and xylene at room conditions. The 6 Wt.% Sm-doped TiO₂ film exhibited the highest response (17.4), with a detection limit of 5 ppm, and fast response (23 s) and recovery (27 s) times. These properties underline the potential of Sm-doped TiO₂ films for efficient room-temperature gas sensors. Their enhanced sensitivity, selectivity, and stability suggest promising applications in environmental monitoring and air quality management, particularly for formaldehyde detection and volatile organic compound discrimination.

Antidepressant response time across intermittent theta burst stimulation regimens and efficacy indicators in adolescents depression: a secondary analysis from a randomized controlled trial

BackgroundAccelerated intermittent theta burst stimulation (aiTBS), which involves the administration of multiple daily sessions of iTBS, represents a novel regimen of repetitive transcranial magnetic stimulation. Studies have suggested that aiTBS may facilitate a fast response among patients with major depressive disorders. However, whether aiTBS can accelerate antidepressant response in adolescents suffering from depression is still unclear. Additionally, the potential indicators associated with antidepressant response in this population are still understudied.MethodsNinety adolescents with depression were recruited and randomly assigned to aiTBS (two 600-pulse sessions of iTBS spaced for 10 min, N = 31), iTBS (one 600-pulse session, N = 29), or sham iTBS (N = 30) for two treatment weeks. Kaplan–Meier analysis was used to estimate the mean time to antidepressant response among the three groups. The analysis of covariance and the multiple logistic regression were applied to identify potential indicators associated with treatment response.ResultsThe mean time to antidepressant response was 7.45 weeks (95% CI: 6.19–8.72) in the aiTBS group, 5.62 weeks (95% CI: 4.09–7.16) in the iTBS group, and 5.07 weeks (95% CI: 3.56–6.58) in the sham group, respectively. The log rank test revealed no significant difference in the mean time to antidepressant response among the three groups (χ2 = 4.156, p = 0.125). For the antidepressant response, there were also no significant interactions between iTBS treatment regimens and the baseline characteristics. Notably, participants with higher motor threshold and worse global function at baseline were likely to be associated with early response and final response, respectively, while those who experiencing child-parent separation were associated with both early and final response. In addition, younger participants were more likely to experience recurrence during follow-up.ConclusionsaiTBS did not demonstrate an advantage in terms of a fast antidepressant response. However, some pretreatment characteristics might serve as indicators of antidepressant response. This relatively simple application based on pretreatment characteristics seems to be a cost-effective method to identify adolescents who are more likely to develop an early antidepressant response and sustain it.Trial registrationThis is a secondary analysis of a primary RCT, which was officially registered in the Chinese Clinical Trial Registry at 19/1/2021 with the number of ChiCTR2100042346. https://www.chictr.org.cn/bin/project/edit?pid=66118.

Biomimetic Honeycomb-like Ti3C2Tx MXene/Bacterial Cellulose Aerogel-Based Flexible Pressure Sensor for the Human-Computer Interface.

The pursuit of efficient and accurate human-computer interface design urgently requires high-performance sensors with pressure sensitivity, a wide detection range, and excellent cycling stability. Herein, a biomimetic honeycomb-like Ti3C2Tx MXene/bacterial cellulose (BC) aerogel with a negative Poisson's ratio (ν = -0.14) synthesized from the bidirectional freeze-drying method is used as the active material for a flexible pressure sensor, which exhibits high sensitivity (20.14 kPa-1), fast response time (100 ms), excellent mechanical durability (5000 cycles), and a low detection limit (responding to a grain of rice weighing about 0.022 g). Moreover, when assembled into the sandwich-structured bending sensor with the aerogel layer at just 0.8 mm in thickness, the aerogel-based device has a wide angular detection range (2.7-156.3°), high sensitivity (0.47 deg-1), and good robustness, proving outstanding electromechanical performance. Significantly, a smart glove consisting of five bending sensors fixed to the proximal knuckles and a flexible circuit board as the signal processing unit was designed for the identification of the shape, demonstrating its promising applications in the field of human-computer interaction.

A Review of Soft Robotic Actuators and Their Applications in Bioengineering, with an Emphasis on HASEL Actuators’ Future Potential

This review will examine the rapidly growing field of soft robotics, with a special emphasis on soft robotic actuators and their applications in bioengineering. Bioengineering has increasingly utilized soft robotics due to their mechanical adaptability and flexibility, with applications including drug delivery, assistive and wearable devices, artificial organs, and prosthetics. Soft robotic applications, as well as the responsive mechanisms employed in soft robotics, include electrical, magnetic, thermal, photo-responsive, and pressure-driven actuators. Special attention is given to hydraulically amplified self-healing electrostatic (HASEL) actuators due to their biomimetic properties and innovative combination of dielectric elastomer actuators (DEAs) and hydraulic actuators, which eliminates the limitations of each actuator while introducing capabilities such as self-healing. HASEL actuators combine the fast response and self-sensing features of DEAs, as well as the force generation and adaptability of hydraulic systems. Their self-healing ability from electrical damage not only makes HASELs a unique technology among others but also makes them promising for long-term bioengineering applications. A key contribution of this study is the comparative analysis of the soft actuators, presented in detailed tables. The performance of soft actuators is assessed against a common set of critical parameters, including specific power, strain, maximum actuation stress, energy efficiency, cycle life, and self-healing capabilities. This study has also identified some important research gaps and potential areas where soft robotics may still be developed in the future. Future research should focus on improvements in power supply design, long-term material durability, and enhanced energy efficiency. This review will serve as an intermediate reference for researchers and system designers, guiding the next generation of advancements in soft robotics within bioengineering.

Oxygenated VOC Detection Using SnO2 Nanoparticles with Uniformly Dispersed Bi2O3

Bi2O3 particles are introduced as foreign additives onto SnO2 nanoparticles (NPs) surfaces for the efficient detection of oxygenated volatile organic compounds (VOCs). Bi2O3-loaded SnO2 materials are prepared via the impregnation method followed by calcination treatment. The abundant Bi2O3/SnO2 interfaces are constructed by the uniform dispersion of Bi2O3 particles on the SnO2 surface. The results of oxygen temperature-programmed desorption suggest that Bi2O3-loaded SnO2 samples display improved surface oxygen ions than neat-SnO2 NPs. As a result, the gas sensor based on 1 mol% Bi2O3-loaded SnO2 (1Bi-L-SnO2) composites shows significantly higher sensitivity and a faster response speed toward various oxygenated VOCs compared with SnO2, especially at 200 °C and 250 °C. The results of catalytic combustion and temperature-programmed reaction measurements reveal the dominant role of adsorption and partial oxidation during ethanol combustion on SnO2 and 1Bi-L-SnO2 surfaces. In this case, the improvement in the sensing performance of the 1Bi-L-SnO2 sensor can be associated with the increase in surface oxygen ions at Bi2O3/SnO2 interfaces. The results confirm the significant role of surface functionalization for sensing materials. The obtained outstanding sensing performance provides the potential application for the simultaneous detection of total oxygenated VOCs in practice.

Antioxidant Responses and Redox Regulation Within Plant-Beneficial Microbe Interaction

The increase in extreme climate events associated with global warming is a great menace to crop productivity nowadays. In addition to abiotic stresses, warmer conditions favor the spread of infectious diseases affecting plant performance. Within this context, beneficial microbes constitute a sustainable alternative for the mitigation of the effects of climate change on plant growth and productivity. Used as biostimulants to improve plant growth, they also increase plant resistance to abiotic and biotic stresses through the generation of a primed status in the plant, leading to a better and faster response to stress. In this review, we have focused on the importance of a balanced redox status for the adequate performance of the plant and revisited the different antioxidant mechanisms supporting the biocontrol effect of beneficial microbes through the adjustment of the levels of reactive oxygen species (ROS). In addition, the different tools for the analysis of antioxidant responses and redox regulation have been evaluated. The importance of redox regulation in the activation of the immune responses through different mechanisms, such as transcriptional regulation, retrograde signaling, and post-translational modification of proteins, emerges as an important research goal for understanding the biocontrol activity of the beneficial microbes.

Machine Learning‐Driven Ultrasensitive WSe2/MWCNT Hybrid‐Based E‐Nose Sensor Array for Volatiles Amines Mixture

AbstractVolatile amines in breath act as biomarkers for kidney and liver diseases. Monitoring these amines, especially when present as a mixture, provides insights into the metabolic state of the body. This study focuses on differentiating volatile amines by systematically modulating the conductivity and sensitivity of WSe2/Multiwalled Carbon Nanotubes composite‐based sensors. The fabricated chemiresistive sensor array demonstrates high selectivity, sensitivity (7.67% ppm−1), fast response and recovery kinetics (32 s/137 s), and accurate discrimination among target amines, even in the presence of other VOCs (volatile organic compounds). The sensor array operates at room temperature and achieves a theoretical limit of detection (LOD) of 387 ppt, 206, 157, and 202 ppb for triethylamine (TEA), dimethylamine (DMA), methylamine (MA), and ammonia (NH3), respectively, demonstrating its suitability for breath sensing and diagnostics. Machine learning (ML) analysis is employed to differentiate between the volatile amines and mixtures with 94% accuracy. The ability to detect these amines at such low ppt and ppb levels underscores the potential of this e‐nose technology for high‐performance applications in early‐stage disease diagnostics.

ANALYSIS OF THE INSTANTANEOUS FILM COOLING EFFECTIVENESS ON SHOWERHEAD FILM COOLING USING FAST RESPONSE PRESSURE SENSITIVE PAINT (FAST-PSP)

Abstract The instantaneous effect of unsteady wakes on film cooling effectiveness using a fast response pressure sensitive paint (PSP) was studied. Testing was performed in a five passage, low speed wind tunnel using scaled versions of typical high-pressure blades (axial chord of 17 cm). The blowing ratios studied include 0.8 and 1.2, with a density ratio of 1.0 and 1.5 at each blowing ratio. Unsteady wakes were produced by a spoked wheel wake generator. The wake generator, utilizing a varying number of rods and rotational speeds, produced Strouhal numbers of 0.1 and 0.3 while the wind tunnel inlet mainstream Reynolds number remained constant at 300,000 (mainstream velocity of 21 m/s) for every test case. For each Strouhal number, blowing ratio and density ratio studied, several positions within the period between rods were recorded. Results show that the location of the wake along a blade's surface had a significant impact on the film cooling effectiveness in the immediate location of the wake. An overall fluctuation of up to 69% in film cooling effectiveness was observed within the wake period. Conclusions also show that while mainstream flows with higher Strouhal numbers tend to decrease film cooling effectiveness, the fluctuation of film cooling effectiveness at higher Strouhal numbers was reduced when compared to results utilizing lower Strouhal numbers. A comparison of results from tests at different density ratios showed a much smaller change in the instantaneous film cooling effectiveness between test cases.

Composition-Tunable Bandgap Engineering of Horizontally Guided CdSxSe1-x Nanowalls for High-Performance Photodetectors.

Composition-adjustable semiconductor nanomaterials have garnered significant attention due to their controllable bandgaps and electronic structures, providing alternative opportunities to regulate photoelectric properties and develop the corresponding multifunction optoelectronic devices. Nevertheless, the large-scale integration of semiconductor nanomaterials into practical devices remains challenging. Here, we report a synthesis strategy for the well-aligned horizontal CdSxSe1-x (x = 0-1) nanowall arrays, which are guided grown on an annealed M-plane sapphire using chemical vapor deposition (CVD) approaches. Microstructural characterizations demonstrate these structures as horizontally guided nanowalls with high-quality crystallinity. Microphotoluminescence (μ-PL) reveals the CdSxSe1-x nanowalls exhibiting continuously tunable spontaneous emissions from 509 nm (pure CdS) to 713 nm (pure CdSe), further confirming that CdSxSe1-x alloys have a continuously tunable bandgap. Notably, a photodetector based on CdSxSe1-x nanowalls displays excellent photoelectric performance, such as high responsivity (3 × 102 ∼ 1 × 103 A/W), high external quantum efficiency (1.01 × 103 ∼ 2.93 × 103), and fast response speed in the millisecond magnitude. Furthermore, the CdS nanowall-based photodetectors exhibit a remarkable image-sensing capability, indicating potential applications in high-performance image sensing in the future. Bandgap continuously tunable nanowall arrays with high-quality crystallinity inject great vitality into the manufacturing of high-performance integrated optoelectronic devices.

Model Predictive Hybrid PID Control and Energy-Saving Performance Analysis of Supercritical Unit

In response to the escalating challenges of rapid load fluctuations and intricate operating environments, supercritical power units demand enhanced control efficiency and adaptability. To this end, this study introduces a novel model predictive hybrid PID control strategy that integrates PID with model predictive control (MPC), leveraging the operational characteristics of multi-loop systems. The proposed strategy adeptly marries the swift response of PID controllers with the foresight and optimization capabilities of MPC. A dynamic model of a supercritical unit is constructed using the subspace identification method. The model’s high precision is confirmed by its alignment with field data. Load change simulations demonstrate that the PID–MPC hybrid controller shows faster response times and more precise tracking capabilities compared to the feedforward-PID strategy. It achieves substantial improvements in the IAE index for three loops, with increases of 29.2%, 54.1%, and 57.3% over the feedforward-PID controller. An energy-saving performance analysis indicates that the proactive control actions of both the PID–MPC and MPC strategies lead to dynamic exergy efficiency and coal consumption rates with a broader range of dynamic process changes. The disturbance scenario simulation regarding the proposed controller achieves faster settling times and minimizes control deviation compared to the traditional controller.

LSTM-Based MPPT Algorithm for Efficient Energy Harvesting of a Solar PV System Under Different Operating Conditions

Solar energy is one of the most favorable renewable energy sources and has undergone significant development in the past few years. This paper investigates a novel concept of harvesting the maximum power of a photovoltaic (PV) system using a long-short term memory (LSTM) to forecast the irradiance value and a feedforward neural network (FNN) to predict the maximum power point (MPP) voltage. This study paves a way to mitigate avoidable inefficiencies that hinder the optimal performance of a PV system, due to the intermittent nature of solar energy. MATLAB/Simulink software platform was used to validate the proposed algorithm with real irradiance data from different geographical and weather conditions. Furthermore, the maximum power point tracking (MPPT) algorithm was implemented in a laboratory setup. The simulation results portray the superiority of the proposed method in terms of tracking performance and dynamic response through a comprehensive case study conducted with five other state-of-the-art MPPT methods selected from conventional, AI based, and bio-inspired MPPT categories. In addition to that, faster response time and lesser oscillations around the MPP were observed, even during volatile weather conditions and partial shading.

Myonuclear and satellite cell content of the vastus lateralis and soleus with70 days of simulated microgravity and the NASA SPRINT exercise program.

We previously observed a range of whole muscle and individual slow and fast myofiber size responses (mean: +4 to -24%) in quadriceps (vastus lateralis) and triceps surae (soleus) muscles of individuals undergoing 70 days of simulated microgravity with or without the NASA SPRINT exercise countermeasures program. The purpose of the current investigation was to further explore, in these same individuals, the content of myonuclei and satellite cells, both of which are key regulators of skeletal muscle mass. Individuals completed 6° head-down-tilt bedrest (BR, n=9), bedrest with resistance and aerobic exercise (BRE, n=9), or bedrest with resistance and aerobic exercise and low-dose testosterone (BRE+T, n=8). The number of myonuclei and satellite cells associated with each slow (myosin heavy chain (MHC) I) and fast (MHC IIa) myofiber in the vastus lateralis was not changed (P>0.05) pre- to post-bedrest within the BR, BRE, or BRE+T groups. Similarly, in the soleus the number of myonuclei associated with each slow and fast myofiber, and the number of satellite cells associated with each slow myofiber were not changed (P>0.05) pre- to post-bedrest within the BR, BRE, or BRE+T groups. It appears that even with relatively large perturbations in muscle mass over a few months of simulated microgravity, or with partially or completely effective exercise countermeasures, human skeletal muscle tightly regulates the abundance of myonuclei and satellite cells. Thus, exercise countermeasures efficacy for skeletal muscle atrophy appears to be independent of myonuclei and satellite cell abundance.

Second-order sliding mode optimization control of an inverted pendulum system based on fuzzy adaptive technology

IntroductionThis paper aims at the control problem of nonlinear systems with uncertainty in general, and avoids the deviation of sliding mode controller from the preset constraint region during the convergence process.MethodsA sliding mode control method based on fuzzy adaptive technique was proposed by constructing obstacle Lyapunov function (BLF). Design problem of fuzzy adaptive second-order sliding mode controller considering output constraints. The Lyapunov function of the cutting barrier is designed, and the fuzzy adaptive second-order sliding mode controller is constructed by combining the Lyapunov function with the regression method. A second-order finite output sliding mode controller is designed for the inverted pendulum system. In the case of unknown external disturbance, the mathematical modeling and force analysis of the first order inverted pendulum system are carried out, and the design problem of the fuzzy adaptive second-order sliding mode controller with output restriction is studied.Results and DiscussionThe proposed fuzzy adaptive second-order sliding mode controller has a good control effect in the inverted pendulum system. The fuzzy adaptive second-order controller stabilizes the sliding mode at 0.1 in 1.25 s, while the fuzzy adaptive second-order controller makes the system state reach equilibrium in 15 s. The accuracy of fuzzy adaptive second-order sliding mode controller reaches 99.2%, which is superior to other methods in terms of balance accuracy and recall rate. The controller not only has a fast response speed, but also can effectively suppress system flutter and ensure the rapid stability of the system after constraints. This research method lays a foundation for the design of fuzzy adaptive sliding mode control algorithm.

Synergistic Doping Strategy with Novel Multi-Carbonyl Conductive Polymer Enables Stable Self-Powered Perovskite Photodetectors.

Lead halide perovskites hold immense promise for optoelectronic applications but still suffer from instability caused by defects. The defects are mainly generated from the film fabrication processes and halide ion migration during long-term storage. Here, a synergistic doping strategy is proposed to enhance the stability of perovskites. A novel multi-carbonyl conductive polymer, poly(benzodifurandione) (PBFDO), is incorporated into the precursor solution to effectively passivate the unoccupied Pb2+ defects in perovskite films and promote the continuous growth of perovskites. An organic iodide, thiophene-2-ethylammonium iodide (TEAI), is doped in the transport layer to inhibit the halide ion migration and enhance the stability of perovskites synergistically. Self-powered photodetectors are constructed with improved stability, maintaining ≈90% of their initial photocurrents after being stored for ≈87 days in a humid atmosphere with 60% relative humidity. The optimized photodetectors show a high detectivity of 8.1×1012 Jones at 680 nm wavelength, wide linear dynamic range of 121.9 dB, and fast response with a rise/fall time of 1.92/1.17µs. A reflection-mode perovskite photoplethysmography testing system is developed, achieving high heart rate testing capabilities. This work suggests the great potential of perovskite photodetectors for noninvasive medical monitoring applications.

Research on an Echo-Signal-Detection Algorithm for Weak and Small Targets Based on GM-APD Remote Active Single-Photon Technology

Geiger-mode avalanche photodiode (GM-APD) is a single-photon-detection device characterized by high sensitivity and fast response, which enables it to detect echo signals of distant targets effectively. Given that weak and small targets possess relatively small volumes and occupy only a small number of pixels, relying solely on neighborhood information for target reconstruction proves to be difficult. Furthermore, during long-distance detection, the optical reflection cross-section is small, making signal photons highly susceptible to being submerged by noise. In this paper, a noise fitting and removal algorithm (NFRA) is proposed. This algorithm can detect the position of the echo signal from the photon statistical histogram submerged by noise and facilitate the reconstruction of weak and small targets. To evaluate the NFRA method, this paper establishes an optical detection system for remotely detecting active single-photon weak and small targets based on GM-APD. Taking unmanned aerial vehicles (UAVs) as weak and small targets for detection, this paper compares the target reconstruction effects of the peak-value method and the neighborhood method. It is thereby verified that under the conditions of a 7 km distance and a signal-to-background ratio (SBR) of 0.0044, the NFRA method can effectively detect the weak echo signal of the UAV.

Efficacy and Safety of Anti-B-Cell Maturation Antigen Chimeric Antigen Receptor T-Cell for the Treatment of Relapsed and Refractory AL Amyloidosis.

The use of anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T-cell (CART) therapy for AL amyloidosis (AL) is limited owing to patient frailty. HBI0101 anti-BCMA CART was the first proof of concept for its applicability to AL. This report addresses the AL patient cohort treated to date within the phase Ia/Ib clinical trial (ClinicalTrials.gov identifier: NCT04720313). After lymphodepletion, most AL patients were infused with 800 × 106 CARTs. Sixteen patients were treated, with a median of four previous lines of therapy (range, 3-10), 14/16 were triple class refractory, and 6/16 were refractory to belantamab. Most patients (13/16) had cardiac involvement, including five with MAYO stage IIIa/IIIb at study entry. Cytokine release syndrome was frequent (14/16) but mostly low grade (grade 3: 3/16, no grade 4/5). No neurologic toxicity or treatment-related deaths were observed. There were five grade 3 AL-related organ deteriorations resolved quickly with supportive care. The overall hematologic response rate was 15/16 (94%) and complete response (CR) was 12/16 (75%). Minimal residual disease negativity was achieved in 9/14 evaluable patients. Most patients (8/13 evaluable) achieved an objective organ response. Seven patients died during long-term follow-up, three while in CR/very good partial response, and the median overall survival was 10.1 months (95% CI, 5.8 to not reached). This largest clinical trial of AL patients treated with anti-BCMA CART demonstrates acceptable and manageable toxicity in a highly frail and resistant population with remarkable efficacy, leading to fast organ responses. Among patients with baseline advanced cardiac disease, deaths in the first year were frequent, suggesting that this effective therapy should be considered earlier in the course of therapy. Anti-BCMA CART may become a powerful tool for improving organ function and survival in patients with AL.

A Tight Load Regulation Hysteretic Boost Converter with Compact and Energy-Efficient Anti-Phase Emulated Current Control

This paper presents a novel, compact, and energy-efficient hysteretic boost converter that employs an anti-phase AC-coupling emulate current control. The proposed scheme utilizes a two-transistor current emulator and a comparator, which allow for fast transient responses and tight closed-loop regulations. This converter was fabricated using a 180 nm CMOS process and was capable of regulating a 5 V output with a 400 mA load capacity from an input voltage range of 2.7 V to 4.5 V. The experimental results demonstrate that the proposed anti-phase AC-coupling emulate current controlling and single hysteretic comparator controlling scheme show lower power/circuit complexity and better static and transient performance. Specifically, under load transitions ranging from 0 mA to 300 mA, the converter exhibits over/undershoot voltages of 38 mV and −42 mV, respectively. Furthermore, the measured load and line regulation performances are 5 mV/A and 2.3 mV/V, respectively. Overall, this study offers a practical and efficient solution for boosting voltage levels while maintaining stable and precise regulation.

Multi-Agent Reinforcement Learning Tracking Control of a Bionic Wheel-Legged Quadruped

This paper presents a novel approach to developing control strategies for mobile robots, specifically the Pegasus, a bionic wheel-legged quadruped robot with unique chassis mechanics that enable four-wheel independent steering and diverse gaits. A multi-agent (MA) reinforcement learning (RL) controller is proposed, treating each leg as an independent agent with the goal of autonomous learning. The framework involves a multi-agent setup to model torso and leg dynamics, incorporating motion guidance optimization signal in the policy training and reward function. By doing so, we address leg schedule patterns for the complex configuration of the Pegasus, the requirement for various gaits, and the design of reward functions for MA-RL agents. Agents were trained using two variations of policy networks based on the framework, and real-world tests show promising results with easy policy transfer from simulation to the actual hardware. The proposed framework models acquired higher rewards and converged faster in training than other variants. Various experiments on the robot deployed framework showed fast response (0.8 s) under disturbance and low linear, angular velocity, and heading error, which was 2.5 cm/s, 0.06 rad/s, and 4°, respectively. Overall, the study demonstrates the feasibility of the proposed MA-RL control framework.

Perovskite Video Camera

AbstractPerovskite photodetectors (PDs) provide opportunities for high‐performance imaging owing to their excellent optoelectronic properties. However, perovskite PD‐based video rate imaging has rarely been reported due to the well‐known slow response and complex array fabrication of perovskite sensors. In this work, a perovskite video camera (PVC) based on a fast perovskite PD combined with computational imaging algorithm is fabricated. The PD has a p‐i‐n structure of FTO/PTAA/MAPbI3/PC61BM/BCP/Au. Owing to combined effects of build‐in electric field, passivation of interface layer, and short carrier transport distance, the proposed PD demonstrates fast response speed of 0.275/0.39 µs (rise/fall). With the help of the computational imaging algorithm, complex array fabrication is bypassed, and successfully demonstrates video rate imaging of a fast‐moving ball with 25 frame s−1 using this single PD. Therefore, this study can call this PVC and believes that the camera provides a new application scenario for perovskite and other emerging optoelectronic materials.