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Transition metal dichalcogenides like MoS2have been considered as crucial channel materials beyond silicon to continuously advance transistor scaling down owing to their two-dimensional structure and exceptional electrical properties. However, the undesirable interface morphology and vibrational phonon frequency mismatch between MoS2and the dielectric layer induce low thermal boundary conductance, resulting in overheating issues and impeding electrical performance improvement in the MoS2field-effect transistors. Here, we employed hybrid high-kdielectric layers of Al2O3/HfO2to simultaneously reduce the interfacial thermal resistance and improve device electrical performance. The enhanced contact, greater vibrational phonon overlapping region, and stronger interfacial bonding force between the top Al2O3layer and MoS2promote the heat removal efficiency across the interface to the substrate. Under the same input power density, the temperature profile of the MoS2transistor on the Al2O3/HfO2has been largely reduced compared to that of the device on HfO2, with a maximum reduction of 49.5 °C. In addition, the field-effect mobility and current of MoS2devices on the Al2O3/HfO2high-kdielectric layers have been significantly improved, attributed to the depressed electron scattering and trap states at the interface. The design of the hybrid high-kdielectric layers provides an efficient solution to simultaneously improve the thermal and electrical performance of the two-dimensional devices.

The superconducting electrodynamic suspension system has many advantages such as no active control, large clearance, and small weight, but its insufficient vertical damping is a problem that needs to be solved. A novel design of the active damping system is proposed, so the vertical damping force can be generated by the interaction between the energized traction coils and the active damping coils. By decomposing the superconducting electrodynamic suspension system into suspension system, traction system, and active damping system, and establishing mathematical models for electromagnetic force calculation in each subsystem, the working mechanisms of each subsystem are well analyzed. Furthermore, based on genetic algorithm, the size and installation position of the active damping coils are optimized, and the optimization result is consistent with the theoretical analysis of the active damping system. A co-simulation platform including electromagnetic force calculation and vehicle dynamics is built, and the co-simulation analysis verified that the proposed active damping system has good suppression effect on vertical and pitch angular motion of the vehicle.

Subcortical brain structures are involved in developmental, psychiatric and neurological disorders. Here we performed genome-wide association studies meta-analyses of intracranial and nine subcortical brain volumes (brainstem, caudate nucleus, putamen, hippocampus, globus pallidus, thalamus, nucleus accumbens, amygdala and the ventral diencephalon) in 74,898 participants of European ancestry. We identified 254 independent loci associated with these brain volumes, explaining up to 35% of phenotypic variance. We observed gene expression in specific neural cell types across differentiation time points, including genes involved in intracellular signaling and brain aging-related processes. Polygenic scores for brain volumes showed predictive ability when applied to individuals of diverse ancestries. We observed causal genetic effects of brain volumes with Parkinson’s disease and attention-deficit/hyperactivity disorder. Findings implicate specific gene expression patterns in brain development and genetic variants in comorbid neuropsychiatric disorders, which could point to a brain substrate and region of action for risk genes implicated in brain diseases.

This article proposes a prescribed-time robust repetitive learning control scheme for uncertain permanent magnet synchronous motor (PMSM) servo systems. An error-tracking approach is developed through constructing a desired error trajectory, such that the exact settling time of the error convergence can be achieved without using any switching mechanism in controller design. In order to achieve high-precision steady-state tracking accuracy, a fully saturated repetitive learning law is developed to reduce the residual periodic steady-state error and drive the tracking error to converge into a sufficiently small region around the origin, such that the rapid transient response and high-precision steady-state tracking accuracy of the PMSM servo system can be both guaranteed simultaneously. Comparative experiments are provided to verify the effectiveness of the proposed method.

Piles, which are classified as deep foundations, are used in civil engineering applications to provide stable support for structures by being driven into the earth. Given the substantial load-bearing capacity of such foundations, it is essential to consider their settling throughout the design process meticulously. Hence, the management and assessment of settlement pose a noteworthy concern in the realm of piling design and construction. The main goal of the current research is to assess the appropriateness of using a neural network model utilizing optimal support vector regression (SVR) analysis to forecast the settling of piles (SP) in rock formations. Both the Aquila optimizer (AO) and the Henry gas solubility optimizer (HGSO) were merged with SVR to get the best possible values for SVR's crucial factors. The purpose of this research is to show that the predetermined methods have not been used to forecast the SP in rocks. The results indicate that both SVR-AO and SVR-HGSO show considerable potential in accurately predicting the SP. Specifically, the SVR-AO model achieved coefficient of determination (R2) values of 0.9957 and 0.994 during its learning and testing phases, while the SVR-HGSO model achieved R2values of 0.9888 and 0.9893, respectively. The results of OBJ presented that the SVR-AO model got the minimum OBJ at 0.2187 in contrast to SVR-HGSO at 0.3436. The results of this study are more powerful and accurate than the literature by gaining the higher values of R2and lower values of error-based metrics. Our research establishes a robust framework for accurately estimating SP in rock formations, offering practical implications for enhancing the design and construction of pile foundations in civil engineering applications. Ultimately, the goal is to leverage machine learning to solve complex problem, make accurate predictions, automate tasks, and gain insights from data.

Purpose: Lung cancer is the leading cause of cancer-related death. Early detection and treatment are crucial to improve survival rates. Radiologists determine whether the nodules are benign or malignant by observing their morphological attributes. However, this can be a challenging task for well-trained doctors. Methods: We propose a more efficient automatic lung nodule analysis method, which establishes a clear cause-and-effect logic relationship between attribute features and malignancy features by incorporating multiple instance learning (MIL). The designed MIL classifier aggregates the learned instance weights and corresponding attribute features to form malignancy features. Compared to existing methods, it starts by mirroring the way radiologists observe nodules, then proceeds to extract the multi-scale morphological attribute characteristics of the nodules. The instance weight also serves as the attribute score of the attribute, providing a reference for consultation. Results: Our method was validated using the LIDC-IDRI dataset and achieved an accuracy of 93.05% on benign-malignant classification task with the added capability of accurately scoring the attributes. Conclusion: The proposed method based on attribute score regression and multi-instance learning establishes the causal relationship between attribute scores and malignancy. This method improves accuracy in nodule classification and addresses the issue of poor model interpretability.

Accurate retinal layer segmentation on optical coherence tomography (OCT) images is hampered by the challenges of collecting OCT images with diverse pathological characterization and balanced distribution. Current generative models can produce high-realistic images and corresponding labels without quantitative limitations by fitting distributions of real collected data. Nevertheless, the diversity of their generated data is still limited due to the inherent imbalance of training data. To address these issues, we propose an image-label pair generation framework that generates diverse and balanced potential data from imbalanced real samples. Specifically, the framework first generates diverse layer masks, and then generates plausible OCT images corresponding to these layer masks using two customized diffusion probabilistic models respectively. To learn from imbalanced data and facilitate balanced generation, we introduce pathological-related conditions to guide the generation processes. To enhance the diversity of the generated image-label pairs, we propose a potential structure modeling technique that transfers the knowledge of diverse sub-structures from lowly- or non-pathological samples to highly pathological samples. We conducted extensive experiments on two public datasets for retinal layer segmentation. Firstly, our method generates OCT images with higher image quality and diversity compared to other generative methods. Furthermore, based on the extensive training with the generated OCT images, downstream retinal layer segmentation tasks demonstrate improved results. The code is publicly available at: https://github.com/nicetomeetu21/GenPSM.

Soft exosuits feature nonlinear, low stiffness, and hysteretic behavior, presenting different mechanical responses during loading and unloading of assistive force. Delivering the desired force to the wearer is a challenge in such a system. To address this issue, this article proposed a novel control strategy with adaptive stiffness and iterative position to optimize the assistive forces of the actuators in compliance with the humanexosuit interface stiffness and relative motion. Specifically, a stiffness model was proposed to describe the force loading and unloading behaviors, further an adaptive stiffness-based force controller was designed to improve the force tracking for whole profile by adaptively adjusting the stiffness parameters related to loading and unloading, and iteratively compensating the position error associated with the force amplitude in the model on a step-by-step basis. This control strategy was implemented on a soft exosuit for hip flexion and extension assistance, and its performance was evaluated through walking tests on six subjects. The results showed that after 4 or 5 iterations of optimization based on the initial parameter settings, the proposed controller could comply with the human-exosuit interface stiffness and achieved an improved force tracking, with a minimal root-mean-square error of 7.5 N in desired force profiles tracking, and a metabolic gain of 14.8%, demonstrating a promising potential of the proposed controller for improving the force tracking and the economy of human walking. Note to Practitioners—Soft exosuits have shown promising outcomes in augmenting human walking and reducing fatigue. However, delivering the desired assistive force accurately to the wearer remains challenging due to the nonlinear and variable stiffness nature of the human-exosuit interaction during walking. This article proposed a control strategy for improving the force tracking performance by optimizing the force-positional relationship of the actuators. Specifically, a stiffness model was established to define the relationship between the force and position of the actuators. This model acts as a virtual spring between the wearer and the exosuit, and stiffness of the spring was adjusted to adapt the wearer. On the Basis of this model, we developed a force tracking controller with adaptive stiffness. It can transmit accurately a desired force trajectory to the wearer by adaptively optimizing the stiffness parameters and iteratively compensating the position error in stiffness model. This controller was implemented on a soft exosuit for hip flexion and extension assistance. The results of treadmill and outdoor walking tests with six subjects confirm the significant effect on optimizing the force-positional relationship, improving the force tracking performance, as well as avoiding force hystereses or friction losses. This research addresses the challenge of force control in human-exosuit interaction with variable stiffness characteristics. The limitation of this work is that it only focuses on hip joint assistance. In the future, we hope to extend this control strategy to other joints to achieve the generality of the approach.

Global climate warming and frequent extreme low-temperature events have made it essential to investigate the impact of low temperatures on parasitic wasps to protect and strengthen farmland biodiversity, which in turn enhances the biological control potential of natural enemies such as parasitic wasps. We systematically examined how low-temperature stress affects the parasitic functional response of Trichopria drosophilaeto Drosophila suzukii(Diptera: Drosophilidae) pupae. Our findings indicate that the parasitic behavior of T. drosophilaetowards D. suzukiipupae aligns with the Holling II functional response model following exposure to different temperatures. Within the temperature range of 8 °C to −8 °C, lower temperatures correlated decreased instantaneous attack rate of T. drosophilaeand an increase in processing time. The search constant Qinitially increased and then decreased with declining temperatures. Short-term low-temperature stress negatively impacted the parasitic and searching abilities of T. drosophilaebut did not alter its parasitic functional response model. Notably, short-term low-temperature stress had minimal effects on the water content, protein content, and total sugar content of male and female T. drosophilaeadults. However, as temperatures decreased, the activities of key enzymes, including GAPDH, SOD, T-AOC, and malondialdehyde (MDA), exhibited an initial increase followed by a decrease. Conversely, the activities of LDH and HOAD decreased, while the activities of CAT and POD increased. Further study on the effect of short-term low temperature on T. drosophilaecan provide a research basis for the large-scale production and low-temperature refrigeration technology of T. drosophilae, and provide a scientific basis for its efficient use in the field.

We devise an end-to-end (E2E) communication channel model that describes the performance of reconfigurable intelligent surface (RIS)-assisted MIMO wireless links. The model borrows the impedance (interaction) matrix formalism from the method of moments (MoM) and provides a physics-based communication model. In configurations where the transmit and receive antenna arrays are distant from the RIS beyond a wavelength, a reduced model provides accurate results for arbitrary RIS unit cell geometry. Importantly, the simplified model configures as a cascaded channel transfer matrix whose mathematical structure is compliant with widely accepted, but less accurate, system-level RIS models. A numerical validation of the communication model is presented for the design of binary RIS structures with scatterers of canonical geometry. Attained results are consistent with path-loss models adopted in communication system design and have been validated with full-wave simulations. Our results shows that the applicability of communication models based on mutual impedance matrices is not restricted to canonical minimum scattering RIS unit cells.

In this article, a low-cost and mechanically robust approach for the design of mechanically phase-tunable reflectarray (RA) elements operating in the C-band is proposed. The proposed element is composed of an open cylindrical shell made of a nonuniform dielectric material. A 2-bit phase tunability is achieved by implementing mechanical rotation of the open cylindrical shell. The proposed element is fabricated by 3-D-printing technology, and the infill rate of the open cylindrical shell is spatially nonuniform. As a result, the effective relative permittivity of the fabricated open cylindrical shell becomes nonuniform. Phase tunability of the fabricated element is demonstrated numerically and experimentally. An RA antenna composed of the proposed elements is designed and fabricated. It is clarified that the RA antenna demonstrates beam scanning coverage up to 50° while its aperture efficiency is comparable to conventional RA antennas.

In this letter, a self-decoupling method is proposed for multi antenna systems based on the identification and suppression of coupling modes. Coupling modes are first identified by characteristic mode analysis, with the coupled power due to each mode quantitatively monitored for the first time. Together with the modal weighting coefficients, the coupling modes to be suppressed are determined. Antennas are then adjusted to break the high-coupling modes without affecting the radiating modes, leading to enhanced isolations. An example involving two identical side-by-side metasurface-based patch antennas with extremely close proximity (0.014λ0) is given. By etching slits at the proper locations of the antennas, the coupling modes have been effectively suppressed without compromising the primary radiation. As a result, the isolations between the antennas are significantly improved by more than 15 dB without additional decoupling structures. The patterns are restored as well. Measurements have been conducted on the antenna systems, showing the feasibility of the self-decoupling method.

A high-gain filtering quasi-Yagi antenna based on compressed third-order mode dipole is presented in this paper. The meander line structure is employed on the dipole to realize the compressed dipole. The current distributions on the meander structure are equal amplitude and out-of-phase to cancel the far-field radiation to realize sidelobes suppression. An in-parallel grounded branch consisting of a bandstop filter and a grounded resistor is used to achieve filtering characteristics with four radiation nulls. The reflection coefficients of the bandstop filter are nearly complementary to that of the antenna to generate the radiation nulls. Moreover, directors are set in front of the dipole symmetrically to achieve a stable gain of the passband. To validate the feasibility of proposed antenna, a prototype is fabricated and measured. Good endfire characteristics are obtained with a bandwidth of 2.58 GHz to 2.82 GHz (8.8%), a peak gain of 9 dBi, sidelobe level (SLL) less than −19 dB, and out-of-band suppression larger than 14 dB. The measured results are in good agreement with the simulation.

Reducing the level of annihilation of electrons and holes is considered to be a feasible strategy to promote piezocatalytic activities. But this strategy is only achieved through cumbersome sample preparation technologies, hindering its practical applications. Herein, we introduce a simple and efficient technique, the conventional solid-state method, to engineer a composite interfacial electric field to solve this problem, and validate it in a composite piezocatalysis composed of potassium sodium niobate ((K, Na)NbO3, KNN) and multiwalled carbon nanotubes (MWCNTs). The KNN-1CNT sample, a piezocatalyst doped with 1 wt % MWCNTs, shows a degradation rate (k) of 127 × 10–3min–1for Rhodamine B (RhB) dye and a hydrogen peroxide (H2O2) production rate of 36 μmol/h, about 27 times more than a reported ferroelectric composite piezocatalyst. The excellent piezocatalytic activities are attributed to the good crystallinity, slightly increased oxygen vacancies, and especially the optimal composite interface electric field. Therefore, our proposed method provides a paradigm for obtaining large-scale perovskite piezocatalysts with high piezocatalytic activities.

Methyl iodide (CH3I) gas as a toxic gas causes great harm to organisms due to its high volatility and high reactivity with biological nucleophiles. Unfortunately, the sensing and detection of CH3I gas are challenging because of the diffusive nature of the gases and its low concentrations in the environment. Herein, we have developed a fast, green, and sensitive CH3I gas visual sensing method based on the capture technology of toxic gases by natural deep eutectic solvents (NADESs) coupled to the halide rapid exchange capability of perovskite nanocrystals (PNCs). In this strategy, NADESs are used as an absorption solution to adsorb gaseous CH3I, while simultaneously exposing I–through the action of the nucleophilic reagent; then, CsPbBr3PNCs were synthesized in NADESs and used as sensing material to achieve I–exchange. Benefiting from the capture and enrichment of CH3I gas, the sensitivity of the gas sensor was highly improved. The sensor exhibited the lowest detection limit (limits of detection) of 164.15 μmol/m3, below the minimum safe level for human inhalation, which is 200 μmol/m3. This breakthrough offers greater possibilities for the quantitative detection of CH3I gas.

This paper presents a discussion on the method, mechanism, and application of adhesive hydrogel in enhancing epidermal signal, focusing on the interface between hydrogel and skin. Due to its excellent conductivity and high adaptability to the skin, the hydrogel is exceptionally suitable for detecting human-machine interfaces, particularly epidermal electromyographic signals. However, the detection of the high epidermal signal is hindered by the gap and low adhesion between hydrogel and skin. This paper addresses these challenges by introducing approaches to reduce the interface gap and increase interface adhesion, thereby enabling the development of hydrogel-based epidermal signal detection arrays with enhanced resolution and detection performance.

In this article, a method to realize the guidance stability of a high-speed electrodynamic suspension (EDS) and electromagnetic propulsion combined system is proposed. This method uses the normal force of the stator windings, which are placed on both sides of the mover, to control the guidance motion of the train. The null-flux coil is considered to be an EDS structure with a high floating/resistance ratio, and has been successfully used in Japanese commercial maglev trains. However, the null-flux coil structure has the disadvantage of insufficient damping coefficient for guidance at high speed, so how to achieve guidance stability of the EDS system is a very important issue. In this article, the electromagnetic force calculation models of the air-core linear synchronous motor and the null-flux coils are established; and an experimental platform is built and experiments are carried out to verify the accuracy of the models. Based on the model, the guiding characteristics of the null-flux coils are analyzed by dynamic co-simulation, and it is found that at low speeds, its guiding stiffness is small and its guiding damping coefficient is positive. At high speeds, there is sufficient guidance stiffness, but the guidance damping coefficient is negative. Thus, an active guidance control method with independent control mode of the two motors is proposed to realize the stable guidance control of the high-speed EDS and electromagnetic propulsion combined system, and the effectiveness of the active guidance control method is verified through the dynamic co-simulation and experiments.

With the aggravation of electromagnetic pollution, electromagnetic interference (EMI) shielding materials have received enormous attention. However, most of the current EMI shielding materials only focus on the shielding effectiveness (SE), neglecting the electromagnetic pollution brought by secondary reflection. In this work, a method of preparing absorption-dominated EMI shielding materials, which are also called green EMI materials, using thermally expandable microspheres (TEMs) and expanded graphite (EG), is proposed. The expansion of TEMs in the EG/waterborne polyurethane mixture can improve the impedance matching between the composite and air. When the content of TEMs is 5 wt % and the content of EG is 15 wt %, the EMI SE of the sample reaches 38.4 dB, and the average reflection power coefficient of this composite is 0.27, indicating that the material mainly shields electromagnetic waves through absorption. Meanwhile, the prepared material also exhibits good stability, maintaining outstanding EMI SE and low value of reflection power coefficient even after the compression–recovery test.

In this letter, a coplanar waveguide-fed wideband polarization-reconfigurable monopole antenna utilizing chalcogenide germanium telluride (GeTe) is proposed. The main radiation part is a rectangular loop, which is split into several symmetrical pieces. The adjacent pieces and ground plane are electrically connected by inverted GeTe chips. By electrical and thermal hybrid excitation, the states of all GeTe chips can be controlled to realize polarization reconfigurability. Additionally, two symmetrical parasitic elements are adopted to improve the impedance bandwidth and axial-ratio bandwidth. Finally, a simple, compact, and low-profile antenna prototype with zero static power is fabricated and tested. The measured results show that the proposed polarization-reconfigurable monopole antenna obtains a wide overlapped bandwidth of 35.7% from 2.62 GHz to 3.76 GHz for linear polarization, left-hand circular polarization, and right-hand circular polarization, which covers sub-6G and WiMAX frequency bands.

A novel method for estimation and optimizing structural parameters of coupled-line bandpass filters (BPFs) using transformer-based estimator (TBE) and multilayer perceptron (MLP) is proposed. Once trained, the TBE can quickly obtain the predicted values of the BPF structural parameters from desired S-parameters, while the trained MLP can replace the time-consuming electromagnetic (EM) simulation process, and establish the mapping from structural parameters to S-parameters. In order to obtain the optimal structural parameters, the trained MLP is combined with genetic algorithm (GA) for fast optimization. To demonstrate the effectiveness of the proposed method, a BPF using three pairs of coupled-line microstrip structure is designed and fabricated. The experimental results demonstrate that the proposed method can quickly and accurately obtain the optimal structural parameters from the desired frequency response of the coupled-line BPF.

• An unreported nanoribbon reinforced carbon/carbon composite is produced. • Comparison of enhancing efficiency of nanoribbons and nanowires is conducted. • Nanoribbons can simultaneously enhance strength and toughness of carbon/carbon composites. • Nanoribbons show significant advantageous in deflecting cracks compared to nanowires. Incorporating one-dimensional (1D) nanofillers into carbon/carbon composites (C/Cs) can increase their mechanical strength. However, this method is ineffective in improving the fracture toughness of C/Cs because cracks can easily pass over the 1D nanofillers, resulting in a flat fracture surface. Herein, we propose a new technique to significantly improve both the strength and toughness of C/Cs by incorporating 2D ribbon-shaped nanofillers. Silicon nitride nanoribbons (SiNNRs) are assembled into a film-like structure and inserted into each layer of a carbon fiber laminate, which is then densified with a pyrocarbon matrix. Due to the large interfacial contact area between the nanoribbon and matrix, ribbon-shaped SiNNRs can efficiently arrest and deflect cracks in both two and three dimensions, exhibiting a higher reinforcement efficiency than that of slender silicon nitride nanowires (SiNNWs). Mechanical tests show that the percentage increases in fracture toughness, flexural strength, and compressive strength of C/Cs produced by SiNNRs are approximately 9.8, 1.8, and 1.25 times higher than those produced by SiNNWs at the same volume fraction of nanofillers, respectively. This study suggests that 2D ribbon-shaped nanofillers are more effective than 1D fibrous nanofillers in enhancing the strength and toughness of C/Cs. : [Display omitted] [ABSTRACT FROM AUTHOR]

A three-phase buck power factor correction (PFC) converter with high frequency and high power density faces the problems of high common-mode (CM) voltage and high voltage stress on switching devices. In this letter, the influence of different pulsewidth modulation (PWM) patterns on CM voltage and voltage stress is studied, and the high-frequency current paths in the three-phase buck PFC converter considering parasitic parameters is revealed. A hybrid PWM pattern is proposed to reduce the CM voltage and voltage stress on switching devices. An experimental prototype 200-kHz switching frequency is built to verify the analysis results in this letter.

The advanced development of soft yet tough hydrogels with high crack resistance significantly extends their application scope from biomedical applications for tissue engineering to emerging electronics applications for soft flexible devices. We investigated the fracture toughness of agar/PAAm hybrid double-network (DN) hydrogels at various strain rates. In large deformations without precut, the loading–unloading curves of agar/PAAm hybrid DN hydrogels exhibit rate-independent hysteresis. However, the fracture toughness of the precut agar/PAAm hybrid DN hydrogel exhibits a transition region around strain rate (ε̇) as 0.12 s–1, and rate-independent toughness is observed at ε̇ < 0.12 s–1, while the fracture toughness decreases significantly if ε̇ > 0.12 s–1. We also discover that the fracture toughness scales with strain rate as Γ ∼ (dλ/dt)−0.58at a high strain rate. A possible mechanism is proposed to interpret this phenomenon. It is believed this work provides new insight into the fracture behavior of hybrid DN gels.

Microstructure and room-temperature mechanical property of TC21 titanium alloy treated by continuous multistep hydrogenation at different temperatures were studied by OM, XRD, TEM and compressive test. Results showed that the size of αphase decreased obviously and βphase became the main phase when the hydrogenation temperature exceeded 1073 K. The content of δhydride increased first and then decreased gradually with the increase of hydrogenation temperature. The strain softening phenomenon appeared during the compression process of TC21 titanium alloy when the hydrogenation temperature exceeded 1073 K and became obvious with the increase of hydrogenation temperature. The ultimate compression of TC21 titanium alloy decreased first and then increased with the increase of hydrogenation temperature, and increased by 67.51% compared with that of the as-received TC21 titanium alloy when the hydrogenation temperature was 1123 K.

Aqueous ammonium ion hybrid supercapacitor (A-HSC) is an efficient energy storage device based on nonmetallic ion carriers (NH4+), which combines advantages such as low cost, safety, and sustainability. However, unstable electrode structures are prone to structural collapse in aqueous electrolytes, leading to fast capacitance decay, especially in host materials represented by vanadium-based oxidation. Here, the Co2+preintercalation strategy is used to stabilize the VO2tunnel structure and improve the electrochemical stability of the fast NH4+storage process. In addition, the understanding of the NH4+storage mechanism has been deepened through ex situ structural characterization and electrochemical analysis. The results indicate that Co2+preintercalation effectively enhances the conductivity and structural stability of VO2, and inhibits the dissolution of V in aqueous electrolytes. In addition, the charge storage mechanisms of NH4+intercalation/deintercalation and the reversible formation/fracture of hydrogen bonds were revealed.

Zeolite-encapsulated metal nanoparticle systems have exhibited interesting catalytic performances via the hydrogen spillover process, yet how to further utilize the function of zeolite supports to promote catalytic properties in such a process is still challenging and has rarely been investigated. Herein, to address this issue, the strategy to strengthen the adsorption energy of reactant onto the zeolite surface via a simple ion exchange method has been implemented. Ion-exchanged linde type A (LTA) zeolite-encapsulated platinum nanoclusters (Pt@NaA, Pt@HA, Pt@KA, and Pt@CaA) were prepared to study the influence of ion exchange on the catalytic performance in the model reaction of hydrogenation of acetophenone to 1-phenylethanol. The reaction results showed that the Pt@CaA catalyst exhibited the best catalytic activity in the series of encapsulated catalysts, and the selectivity of 1-phenylethanol approached 100%. As revealed by density functional theory (DFT) calculations and acetophenone temperature-programmed desorption (acetophenone-TPD) experiments, in comparison with introduced cations of Na+, H+, and K+, ion-exchanged Ca2+on the zeolite maximumly enhanced the adsorption of carbonyl groups in acetophenone, playing a critical role in achieving the highest activity and excellent catalytic selectivity among the Pt@A catalysts.

Escherichia coliSeptu system, an anti-phage defense system, comprises two components: PtuA and PtuB. PtuA contains an ATPase domain, while PtuB is predicted to function as a nuclease. Here we show that PtuA and PtuB form a stable complex with a 6:2 stoichiometry. Cryo-electron microscopy structure of PtuAB reveals a distinctive horseshoe-like configuration. PtuA adopts a hexameric arrangement, organized as an asymmetric trimer of dimers, contrasting the ring-like structure by other ATPases. Notably, the three pairs of PtuA dimers assume distinct conformations and fulfill unique roles in recruiting PtuB. Our functional assays have further illuminated the importance of the oligomeric assembly of PtuAB in anti-phage defense. Moreover, we have uncovered that ATP molecules can directly bind to PtuA and inhibit the activities of PtuAB. Together, the assembly and function of the Septu system shed light on understanding other ATPase-containing systems in bacterial immunity.