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Low-temperature proton exchange membrane fuel cells (PEMFCs) reuqire highly pure hydrogen gas due to their extreme sensitivity to carbon monoxide (CO) contamination, which poses a challenge for using cost-effective reformed hydrogen sources. To address this issue, we have developed a surface modification strategy by applying a 0.5–0.91 nm amorphous carbon nitride layer onto PtRu/C substrates. The electrochemical measurements indicate that the modification selectively facilitates hydrogen gas transport to a surface while inhibiting carbon monoxide diffusion. The kinetic studies of CO adsorption reveal that the surface modification significantly reduces CO adsorption, effectively halving the rate compared to conventional catalysts. Additionally, rotating disk electrode experiments show that the catalyst modified with amorphous carbon nitride layer maintains stable operation for over 20 h with 1000 ppm of CO/H2. Furthermore, it supports stable discharge at 1 A cm–2in PEMFCs with up to 10 ppm of CO, a concentration far exceeding the widely accepted standard of 0.2 ppm.

In this letter, a compact wide-beam open-loop antenna is presented for small flight vehicle communication applications. The object is comprised of a disc-shaped metal pedestal and a vertical substrate. The primary radiated structure is the open loop, which is printed on the vertical substrate and fed by an edge coaxial line. Wide beam characteristics have been verified at 3.542 GHz to 3.612 GHz, with a half-power beamwidth (HPBW) of 278° and 240° in the xoz- and yoz-planes, respectively. The total dimensions are calculated as π × 0.2λ0 × 0.2λ0 × 0.09λ0, where λ0 represents the wavelength of the central frequency in free space. The suggested design prototype has been fabricated and evaluated inside the microwave anechoic chamber, and the measured results closely correspond to the simulated. With its wide beam, compact size, lightweight, and affordable price, the suggested design is anticipated to be a good candidate for small flight vehicle applications.

This communication presents a low-profile and low-cost metal-only folded transmitarray antenna (FTA) based on chiral metasurface, which reduces the profile by simultaneously folding the propagation path of the waves and simplifying the structure of transmitarray. Unlike traditional elements of transmitarrays, the proposed element consists of only two metal layers without any vertical metal structures between the layers, which achieves high transmission efficiency and 360° phase shift capability. Furthermore, a metal-only reflective plate with polarization conversion characteristics is introduced to reduce the profile of the antenna. Due to the polarization regulation ability of the element, the propagation path of incident waves is folded twice to reduce the FTA’s profile to 1/3 of traditional transmitarray antennas (TAs). Consequently, the heights of the array and the whole antenna are only $0.14\lambda _{0}$ and $6.88\lambda _{0}$ (including the feed source), respectively. A prototype operating at 11.45–13.25 GHz is fabricated and measured. The measured maximum gain of the antenna is 27 dBi, with a total efficiency of 35.3%. These results indicate that the proposed antenna significantly reduces the profile, cost, and processing complexity while ensuring total efficiency and bandwidth. The proposed metal-only FTA has significant applications in some scenarios requiring low profile, low cost, and high-power capacity.

The bottleneck of Li metal batteries toward practical applications lies at inferior cyclability as well as Li dendrite issues. As a promising solution, an interface engineering strategy is proposed herein for the Li anode through constructing a hybrid artificial interface. It is assembled onto the Li anode using photocontrolled free radical polymerization (photo-CRP) of polyethylene glycol diacrylate-hexafluorobutyl methacrylate and hexafluorobutyl methacrylate-trifluoroethyl carbonate (PEGDA-HFMBA@HFMBA-FEMC or PH@HF layer). Among such hybrid interfaces, the interior layer of PEGDA-HFMBA exists as a protective shield with flexibility and fracture resistance, while the exterior layer of HFMBA-FEMC plays a role as a LiF reservoir to promote Li mass transfer and its even electrodeposition. In the meantime, some excess HFMBA and FEMC monomers further dissolve into the electrolyte as molecular additives, followed by in situ generation of a thin and robust LiF-rich cathode electrolyte interface (CEI). With the resulting Li anode, Li/NCM811 full cells showcase multifold cyclability amplification in comparison to cells using Bare-Li, covering durable cyclability with a capacity retention of 81.8% after 400 cycles. When the cutoff voltage is elevated to 4.5 V or the working temperature is elevated to 45 °C, the cells still maintain a stable operation for extending 300 cycles.

Fully-connected beamforming networks (FCBNs) can provide better performance in a hybrid beamforming (HBF) architecture for massive multiple-input-multiple-output (MIMO) systems. The traditional FCBN adopts the “splitters + phase shifters + attenuators + combiners” architecture, which has a huge intrinsic loss by the theoretical analysis. The network loss and topology complexity pose challenges for its engineering applications. To address the aforementioned issues, this article proposes a new efficient FCBN architecture, eliminating the intrinsic loss of the network. The proposed new FCBN architecture consists of tunable and fixed directional couplers and phase shifters in cascading, achieving both amplitude and phase adjustments. For synthesizing such a tunable network with arbitrary I/O ports, the complete QR factorization synthesis method with the corresponding tunable complex Givens rotation matrix has been proposed and proved. To demonstrate the proposed synthesis method, a $2\times 4$ FCBN network has been synthesized, fabricated, and measured. Concentrating on the characteristics of the FCBN, an optimization process has been introduced to simplify hardware topology complexity. The results show that the proposed FCBN architecture has advantages in no intrinsic loss, simple topology, and low cost, making it widely applied in wireless communication systems to improve the system efficiency.

Graphical abstract:

The S atom in the first shell breaks the local charge symmetry of the Co active center, resulting in the enhanced adsorption of oxygen and reaction intermediates during the oxygen reduction reaction (ORR) process, thereby greatly improving the activity and 4-electron selectivity of the ORR.

The surface electron structure of metal catalysts plays a crucial role in their catalytic performance. Nevertheless, developing simple and reliable methods to evaluate this structure remains challenging. Here, we introduce an electrochemical in situ Fourier transform infrared spectroscopy (FTIRS) CO adsorption probe method to study the surface structure of Pt-based alloy catalysts. Combined with high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and the in situ FTIRS CO-probe method, our study demonstrated that the red/blueshift of COadwavenumbers could be attributed to the modifications in the surface Pt electronic structure, resulting in a shift of the d-band center for Pt. This would enhance the d-π* feedback effect between Pt and CO and result in the redshifts of the CO adsorption peaks. This phenomenon can also be observed in transition metal–nitrogen–carbon catalysts, further proving the universality of the in situ FTIRS CO-probe method.

Decoupled water electrolysis systems, incorporating a reversible redox mediator that allows for the construction of membrane-free electrolyzers, have emerged as a promising approach to produce high-purity hydrogen with remarkable flexibility. The key factor crucial for practical applications lies in the development of mediator electrodes that possess suitable redox potential, high redox capacity, excellent cycling reversibility and stability. Herein, we introduce a novel concept of oxygen-mediating redox mediators (ORMs) employing Bi2O3as an example material, which are capable of sequestering oxygen during the hydrogen evolution reaction and subsequently releasing it to generate oxygen gas under alkaline conditions. Thanks to its remarkable reversible redox activity and specific capacity, the Bi2O3electrode boasts an impressive reversible specific capacity of 300.8 mA h g–1and delivers outstanding cycling performance for >1000 cycles at a current density of 2.0 A g–1. Furthermore, the implementation of such a decoupled alkaline water electrolysis system can be integrated with a Bi2O3–Zn battery, enabling both power-to-fuel (hydrogen production) and chemical-to-power (rechargeable Bi2O3–Zn battery) conversion. With many oxygen-carrier materials readily available and the potential integration with rechargeable alkaline batteries, this study provides an alternative competitive route for membrane-free decoupled water splitting through the oxygen-mediating mechanism with combined energy transformation and storage.

Nitrate (NO3–) in wastewater poses a serious threat to human health and the ecological environment. The electrocatalytic NO3–reduction to ammonia (NH3) reaction (NO3–RR) emerges as a promising carbon-free energy route for enabling NO3–removal and sustainable NH3synthesis. However, it remains a challenge to achieve high Faraday efficiencies at a wide potential window due to the complex multiple-electron reduction process. Herein, spatially separated dual-metal tandem electrocatalysts made of a nitrogen-doped ordered mesoporous carbon support with ultrasmall and high-content Cu nanoparticles encapsulated inside and large and low-content Ru nanoparticles dispersed on the external surface (denoted as Ru/Cu@NOMC) are designed. In electrocatalytic NO3–RR, the Cu sites can quickly convert NO3–to adsorbed NO2–(*NO2–), while the Ru sites can efficiently produce active hydrogen (*H) to enhance the kinetics of converting *NO2–to NH3on the Cu sites. Due to the synergistic effect between the Cu and Ru sites, Ru/Cu@NOMC exhibits a maximum NH3Faradaic efficiency (FENH3) of approximately 100% at −0.1 V vs reversible hydrogen electrode (RHE) and a high NH3yield rate of 1267 mmol gcat–1h–1at −0.5 V vs RHE. Finite element method (FEM) simulation and electrochemical in situ Raman spectroscopy revealed that the mesoporous framework can enhance the intermediate concentration due to the in situ confinement effect. Thanks to the Cu–Ru synergistic effect and the mesopore confinement effect, a wide potential window of approximately 500 mV for FENH3over 90% and a superior stability for NH3production over 156 h can be achieved on the Ru/Cu@NOMC catalyst.

The spatial constraints imposed by the DNA structure have significant implications for the walking efficiency of three-dimensional DNA walkers. However, accurately quantifying and manipulating steric hindrance remains a challenging task. This study presents a steric hindrance-controlled DNA walker utilizing an enzymatic strand displacement amplification (ESDA) strategy for detecting microRNA-21 (miR-21) with tunable dynamic range and sensitivity. The steric hindrance of the DNA walker was precisely manipulated by varying the length of empty bases from 6.5 Å to 27.4 Å at the end of the track strand and adjusting the volumetric dimensions of the hairpin structure from 9.13 nm3to 26.2 nm3at the terminus of the single-foot DNA walking strand. This method demonstrated a tunable limit of detection for miR-21 ranging from 3.6 aM to 35.6 nM, along with a dynamic range from ∼100-fold to ∼166 000-fold. Impressively, it exhibited successful identification of cancer cells and clinical serum samples with high miR-21 expression. The proposed novel strategy not only enables tunable detection of miRNA through the regulation of steric hindrance but also achieves accurate and quantitative analysis of the steric hindrance effect, promising broader applications in personalized medicine, early disease detection, and drug development.

As the core component in proton exchange membrane fuel cells, carbon corrosion is one of the main issues that can cause cell performance degradation. In situ analysis of carbon corrosion with high spatial and temporal resolution is helpful to reveal the mechanism and influencing factors of carbon corrosion and provides guidance for catalyst optimization. Herein, we investigate the carbon corrosion process by in situ transmission electron microscopy (TEM) and other characterization methods. The microstructure evolution and molecular scale reaction mechanisms of carbon corrosion have been analyzed. Carbon corrosion is extremely severe when exposed to a high potential (1< E< 1.5 V versus RHE). At the high potential, carbon undergoes incomplete oxidation and forms numerous oxygen-containing functional groups, which improves the hydrophilicity of the carbon surface. In this case, the pore distribution changes with corrosion of carbon and the destruction of the carbon microstructure causes the expansion of volume. Through the comparison experiment of hollow carbon spheres and carbon black XC-72, it is found that the observed volume expansion can be greatly alleviated with the increase in graphitization. This provides new visual understanding of why highly graphitized carbon has higher durability.

This letter presents a multiband modified Yagi antenna, which can operate at four individual frequency bands (0.87 GHz, 1.53 GHz, 2.32 GHz, and 5.55 GHz). The proposed antenna consists of four groups of Yagi elements cascading in a shared transverse aperture. Each Yagi element has one dipole as the radiator, one or two directors, and one reflector corresponding to one resonant frequency. In order to realize independent control of each frequency band, a high-impedance structure is employed between two adjacent Yagi elements, which can be used to reduce the mutual coupling as well. Therefore, the four groups of Yagi elements can work individually or in combination to achieve single-band, dual-band, tri-band and quad-band Yagi antennas. The measured results show that the proposed antenna can achieve a −10 dB impedance bandwidths of 11.5% [(0.82 to 0.92) GHz], 10.5% [(1.45 to 1.61) GHz], 17.7% [(2.11 to 2.52) GHz], and 16.2% [(5.1 to 6) GHz] for the four operating bands. The maximum realized gains for each band are 5.8 dB, 7.9 dB, 6.7 dB, and 4.8 dB.

A feeding network with arbitrary I/O ports and excitations is useful in wireless communication systems, especially in near-field focusing (NFF) scenarios, where the excitation weights should take the antenna position into consideration.In this brief, a new feeding network synthesis methodology based on modified QR factorization theory for arbitrary I/O ports and excitations has been proposed. By establishing the mapping relationship of the complex Givens rotation matrix with multi-port devices, the transmission matrix of the orthogonal feeding network can be decomposed into complex Givens rotation matrices in cascading. Moreover, the matrix decomposition order can be further modified for the feeding network simplification. As an example, a specialized orthogonal $2\times 8$ feeding network is synthesized for the NFF application operating at 3.5 GHz. The obtained NFF results show the potential of the feeding network design theory and testify to its extensive application scenarios.

Hard carbon (HC) is a promising anode candidate for Na-ion batteries (NIBs) because of its excellent Na-storage performance, abundance, and low cost. However, a precise understanding of its Na-storage behavior remains elusive. Herein, based on the D2O/H2SO4-based TMS results collected on charged/discharged state HC electrodes, detailed Na-storage mechanisms (the Na-storage states and active sites in different voltage regions), specific SEI dynamic evolution process (formation, rupture, regeneration and loss), and irreversible capacity contribution (dead Na0, NaH, etc.) were elucidated. Moreover, by employing the online electrochemical mass spectrometry (OEMS) to monitor the gassing behavior of HC-Na half-cell during the overdischarging process, a surprising rehydrogen evolution reaction (re-HER) process at around 0.02 V vs Na+/Na was identified, indicating the occurrence of Na-plating above 0 V vs Na+/Na. Additionally, the typical fluorine ethylene carbonate (FEC) additive was demonstrated to reduce the accumulation of dead Na0and inhibit the re-HER process triggered by plated Na.

To find a better way to estimate the lift force induced by an interceptor on a high-speed mono-hull ship, a series of high-speed mono-hull ship models are designed and investigated under different conditions. Different lift forces are obtained by numerical calculations and validated by a model test in a towing tank. The factors that influence the force are the interceptor height, velocity, draft, and deadrise angle. The relationship between each factor and the induced lift force is investigated and obtained. We found that the induced lift mainly depends on the interceptor height and advancing velocity, and is proportional to the square of the interceptor height and velocity. The results also showed that the effects of the draft and deadrise angle are relatively less important, and the relationship between the induced lift and these two factors is generally linear. Based on the results, a formula including the combined effect of all factors used to estimate the lift force induced by the interceptor is developed based on systematic analysis. The proposed formula could be used to estimate the lift force induced by interceptors, especially under high-speed condition.

A 1–2-GHz wide-scanning cylindrical conformal array antenna with a large curvature is proposed in this article. A novel dipole element with integrated feeding balun is proposed, featuring a bending angle of 30° in the E-plane, and a metal wall is employed to suppress common-mode resonance. Optimizations based on a cylindrical conformal subarray further improve the beam scanning ability. According to the analyses, the element large-curvature bending suppresses the edge element impedance mismatch and array beam pointing deviation. In addition, the cylindrical contour of the proposed array leads to an obvious scattering cross section reduction (SCSR) compared to flat metal ground, and the co-polarized (co-pol) SCSR is enlarged by in-band absorptions of array elements. To increase the cross-polarized (cr-pol) SCSR, a cr-pol absorbing structure terminated by a resistor is designed in the flexible impedance matching layer of a polyimide (PI) film. Consequently, the proposed conformal dipole array antenna achieves both notable co-/cr-pol in-band monostatic SCSRs, as well as the beam scanning in the E-/H-planes within ±75°/±60°. The correctness of the proposed design method is verified by the experiment on an $8\times 6$ cylindrical conformal array prototype, and the measured results demonstrate the broadband wide-scanning performances and low-scattering characteristics.

The purpose of this brief is to present a two-dimensional wideband and wide beam-steering phased array antenna with a combined superstrate. The arched metal columns are incorporated in the dipole array antenna to suppress the mutual coupling, resulting in wideband matching and wide beamwidth characteristics in the ${E}$ -plane. A combined superstrate, comprising metasurface slabs and a dielectric layer, is located above the antenna to increase the beamwidth and enhance the impedance matching property. The same effect can be achieved by optimizing the curvature of the exponential curves of the dipole edge to obtain a deformed dipole. To showcase the wideband wide-scanning capability of the device, a prototype is designed with a scanning range of ±60° in both the ${E}$ - and ${H}$ - plane at 2.5-4.75 GHz (62.1%, active VSWR $\leq 2$ ). The simulated co-polarization gain of the array is close to the ideal aperture, which decreases no more than 3 dB in large-angle scanning. To ascertain the viability of the proposed design, an $8\times 8$ prototype is manufactured and subjected to testing. The overall dimension is $2.23\lambda _{0}\times 2.23\lambda _{0}\times 0.24\lambda _{0}\,\,(\lambda _{0}$ is the free space wavelength at 2.5 GHz). Based on the findings of the experiment, there is a good concurrence between the design and measurement outcomes. The proposed array demonstrates the advantages of low-cost, broadband, and wide beam-steering capability, which is expected to be suitable for the implementation of fifth-generation (5G) communication systems.

The void-free filling of microvia through copper electronic plating in printed circuit board application relies critically on multi-component additives including suppressor, accelerator, and leveler. In this study and for the first time, we have developed a new hypotoxic additive, Polixetonium Chloride (PC), as a single component additive in copper electronic plating. Chronocoulometric measurements and finite element method computations combined with Cu electronic plating indicate that the PC can inhibit copper deposition at the mouth of microvia and improve copper deposition at the bottom of microvia by increasing local current densities. Chronopotentiometric studies and in situ FTIR spectroscopic analysis together with density functional theory calculations illustrate that Cl−behaves the anchor of PC to enhance its adsorption, and the adsorption ability of PC in microvia is gradually weakened from top to bottom, which is in favor of the electrodeposition of cupric ions at the bottom of microvia for void-free filling.

ABSTRACT As promising structural materials in seismic isolation and energy dissipation systems, low yield point (LYP) steels have been developed and have begun to be adopted in seismic design. This [...]

ABSTRACT As new advanced high performance structural steels, low yield point (LYP) steels have been widely accepted and used in the technology of energy dissipation for seismic design. This paper [...]

ABSTRACT For seismic control and isolation techniques, low yield point steels are among the most reliable and ideal energy-dissipating materials. Structures under earthquake conditions are usually subjected to cyclic loads [...]

Intelligent utilization of the anionic redox reaction (ARR) in Li-rich cathodes is an advanced strategy for the practical implementation of next-generation high-energy-density rechargeable batteries. However, due to the intrinsic complexity of ARR (e.g., nucleophilic attacks), the instability of the cathode-electrolyte interphase (CEI) on a Li-rich cathode presents more challenges than typical high-voltage cathodes. Here, we manipulate CEI interfacial engineering by introducing an all-fluorinated electrolyte and exploiting its interaction with the nucleophilic attack to construct a gradient CEI containing a pair of fluorinated layers on a Li-rich cathode, delivering enhanced interfacial stability. Negative/detrimental nucleophilic electrolyte decomposition has been efficiently evolved to further reinforce CEI fabrication, resulting in the construction of LiF-based indurated outer shield and fluorinated polymer-based flexible inner sheaths. Gradient interphase engineering dramatically improved the capacity retention of the Li-rich cathode from 43 to 71% after 800 cycles and achieved superior cycling stability in anode-free and pouch-type full cells (98.8% capacity retention, 220 cycles), respectively.

Mantidisflavin A (1) was isolated from the egg cases of the Tenodera sinensisSaussure. It exhibits an unprecedented 6/6/6/5/5 skeleton, accompanied by the formation of two additional fused heterocycles through a novel C–C bond and an oxygen bridge on riboflavin backbone. The structure of 1was identified by spectroscopic and computational methods. To assess the inhibitory effect against renal fibrosis, compound 1was evaluated in TGF-β1-induced rat kidney epithelial cells, and the results were compared to those of its precursor, riboflavin.

Astrocyte-derived IL-3 activates the corresponding receptor IL-3Rα in microglia. This cross-talk between astrocytes and microglia ameliorates the pathology of Alzheimer’s disease in mice. In this study we investigated the role of IL-3/IL-3Rα cross-talk and its regulatory mechanisms in ischemic stroke. Ischemic stroke was induced in mice by intraluminal occlusion of the right middle cerebral artery (MCA) for 60 min followed by reperfusion (I/R). Human astrocytes or microglia subjected to oxygen-glucose deprivation and reoxygenation (OGD/Re) were used as in vitro models of brain ischemia. We showed that both I/R and OGD/Re significantly induced decreases in astrocytic IL-3 and microglial IL-3Rα protein levels, accompanied by pro-inflammatory activation of A1-type astrocytes and M1-type microglia. Importantly, astrocyte-derived VEGFD acting on VEGFR3 of astrocytes and microglia contributed to the cross-talk dysfunction and pro-inflammatory activation of the two glial cells, thereby mediating neuronal cell damage. By using metabolomics and multiple biochemical approaches, we demonstrated that IL-3 supplementation to microglia reversed OGD/Re-induced lipid metabolic reprogramming evidenced by upregulated expression of CPT1A, a rate-limiting enzyme for the mitochondrial β-oxidation, and increased levels of glycerophospholipids, the major components of cellular membranes, causing reduced accumulation of lipid droplets, thus reduced pro-inflammatory activation and necrosis, as well as increased phagocytosis of microglia. Notably, exogenous IL-3 and the VEGFR antagonist axitinib reestablished the cross-talk of IL-3/IL-3Rα, improving microglial lipid metabolic levels via upregulation of CPT1A, restoring microglial phagocytotic function and attenuating microglial pro-inflammatory activation, ultimately contributing to brain recovery from I/R insult. Our results demonstrate that VEGFD/VEGFR3 signaling contributes to the dysfunction of the astrocyte IL-3/microglia IL-3Rα cross-talk and drives pro-inflammatory activation, causing lipid metabolic reprogramming of microglia. These insights suggest VEGFR3 antagonism or restoring IL-3 levels as a potential therapeutic strategy for ischemic stroke.

In this letter, a low radar cross section (RCS) Vivaldi antenna is designed based on characteristic mode analysis (CMA). The characteristic mode theory (CMT) is first applied to wideband RCS reduction of the Vivaldi antenna. Three typical frequency points are selected at low (8 GHz), medium (10 GHz) and high frequency (12 GHz), respectively, for CMA with the aim of realizing broadband RCS reduction. Different from the traditional analysis of mode weighting coefficient (MWC) and current distribution, the analysis of the magnitude and phase of each mode is further introduced, which makes the analysis more effective for guiding the RCS reduction design. By modification, the cheapest and most effective way, scattering currents corresponding to the dominant scattering modes are effectively suppressed so that the monostatic RCS is reduced as much as possible. Simulated and measured results show that compared with the reference antenna, the peak reduction of RCS of the proposed antenna reaches 27.36 dB, and the design doesn't degrade the radiation performance.

Meshed dc grids help improve the current network's configuration, flexible power management, and reliable power supply. However, the existing power converters implemented in dc grids do not have enough controllability in adjusting each feeder's power, leading to transmission congestion, overloads, and high-power loss issues. The dc power flow controller (DCPFC) is prominent in addressing problems with a better system performance. This article proposes an embedded dc power flow controller (eDCPFC) with full-bridge modular multilevel converter (MMC) (FB-MMC) topology. The eDCPFC is directly integrated into a host MMC. The device's energy is balanced through the coordinated control of the eDCPFC and the host MMC without using isolation transformers or external power supplies. The working principle and the corresponding control strategies of the FB-MMC type eDCPFC and its host MMC are elaborated. Experimental results conducted in a scaled-down prototype validate the feasibility and effectiveness of the proposed topology and control schemes under typical working conditions.

As a critical component of a tunnel boring machine (TBM), the precise condition monitoring and fault analysis of the main bearing is essential to guarantee the safety and efficiency of the TBM cutter drive. Currently, under conditions of strong noise and complex working environments, traditional signal decomposition and machine learning methods struggle to extract weak fault features and achieve high fault classification accuracy. To address these issues, we propose a novel residual denoising and multiscale attention-based weighted domain adaptation network (RDMA-WDAN) for TBM main bearing fault diagnosis. Our approach skillfully designs a deep feature extractor incorporating residual denoising and multiscale attention modules, achieving better domain adaptation despite significant domain interference. The residual denoising component utilizes a convolutional block to extract noise features, removing them via residual connections. Meanwhile, the multiscale attention module uses a 4-branch convolution and 3 pooling strategy-based channel-spatial attention mechanism to extract multiscale features, concentrating on deep fault features. During training, a weighting mechanism is introduced to prioritize domain samples with clear fault features. This optimizes the deep feature extractor to obtain common features, enhancing domain adaptation. A low-speed and heavy-loaded bearing testbed was built, and fault data sets were established to validate the proposed method. Comparative experiments show that in noise domain adaptation tasks, proposed the RDMA–WDAN significantly improves target domain classification accuracy by 42.544%, 23.088%, 43.133%, 16.344%, 5.022%, and 9.233% over dense connection network (DenseNet), squeeze-excitation residual network (SE-ResNet), antinoise multiscale convolutional neural network (ANMSCNN), multiscale attention module-based convolutional neural network (MSAMCNN), domain adaptation network, and hybrid weighted domain adaptation (HWDA). In combined noise and working condition domain adaptation tasks, the RDMA–WDAN improves the accuracy by 45.672%, 23.188%, 43.266%, 16.077%, 5.716%, and 9.678% compared with baseline models.

This article presents a dual-polarized wide-angle scanning phased array antenna for 5G application. This antenna has the properties of compact structure, orthogonal polarization, and low elevation coverage. The parasitic metal columns are used to suppress the abnormal resonance and improve the beamwidth of the elements. Bent frame metal arms are applied to make a compact element size of $0.37\times 0.37\times 0.33\lambda _{0}^{3}$ (where $\lambda _{0}$ represents the center frequency wavelength), which further broadens the beamwidth of the antenna element and optimizes the active reflection coefficients for large-angle scanning within the operating frequency band. Subsequently, a $6\times 6$ antenna array prototype based on the proposed element is designed and fabricated. The measured results indicate that the operational frequency band of the array spans from 3.0 to 3.8 GHz, and a wide scanning angle of ±80° can be achieved with a gain fluctuation below 7 dB. The measured results are closely correlated with the simulated ones, which confirms the effectiveness of the proposed design for wide-angle scanning.

The soft normally-open points (SNOP) have been proposed in response to challenges raised from renewable energy in the grid. Main scheme adopted in SNOP demonstration projects are back-to-back modular multilevel converter (BTB-MMC), which is costly in multifeeder scenarios. The series shunt multiport SNOP (S2-MSNOP) can reduce the cost and volume. But its energy balance faces difficulties under operating conditions where reactive power provided by the cascaded H-bridge of the device is too small, thus impeding its practical implementation. Accordingly, this article presents a novel delta-type serial shunt soft-normally open points (D-S3NOP) scheme, offering a practical multifeeder interconnection solution. D-S3NOP employs an internal circulating current mechanism to achieve energy balance among its constituent parts, thereby expanding the power flow regulation range. First, the topology feature and working principle of D-S3NOP are presented. Subsequently, a suitable control strategy is designed. Comparison of power flow regulation area and cost among S2-MSNOP, D-S3NOP, and BTB-MMC is made after. Finally, a simulation model and an experimental prototype are constructed for verifying the effectiveness of D-S3NOP.

The multiport power electronic transformer (PET) is a critical equipment in ac/dc hybrid distribution grids, which has the functions of multidirectional power flow, flexible power flow regulation and reactive power control, and fault isolation. However, most proposed PETs have only a single-medium-voltage-ac (MVac) port, limiting their application scenarios in distribution grids. To address this problem, in this article, we propose a PET topology with multiple controllable MVac ports based on the cascaded H-bridge PET. The proposed PET topology can connect to multiple-MVac feeders and supply low-voltage-side loads through multiple terminals, achieving the full utilization of the remaining capacity of connected feeders, thus delaying the distribution capacity expansion and grid upgrade due to the rapid development of energy electrification. Besides, the decoupling control of active and reactive power for each feeder can be achieved. In this article, the operating principle, energy balance mechanism, control strategies, and design and comprehensive comparison of the proposed topology are studied. The simulation and experimental results demonstrate the validity of the proposed topology and control strategy.

A wide-angle scanning array based on a new pattern-reconfigurable element (PRE) is presented. The PRE is formed by docking two modified coupling planar inverted F-shaped antennas, one as the main element and the other as a parasitic element. Amplitude and phase perturbations are attached to the binary array, forming a tilt pattern and a wide operating band. A 1 × 8 antenna array based on the PRE is designed. The active patterns tilt gradually with the increase of frequency, suppressing the grating lobes appearing at low elevations and realizing wide-angle scanning under a large spacing. The special bias circuitry reduces the impact of additional wires on the array performance. The antenna array prototype was manufactured and measured to verify the design. The dimension is 3.93λ0 × 0.61λ0 × 0.08λ0 (λ0 is the free-space wavelength at 4.1 GHz). The main lobe realized ±70° scanning range at 3.75–4.5 GHz (18.3%) with a gain fluctuation within 3.2 dB. The maximum sidelobe levels remain below −7.2 dB during scanning. The cross-polarization levels are kept below −45 dB. The measurement is consistent with the simulated results.

High cost and large volume are always associated with the conventional unified power flow controller (UPFC) formed by two back-to-back connected voltage source converters and two transformers. Both additional series-connected converters and their adjacent transformers are necessitated when controlling the power flow among multiple transmission lines. Such implementation will further increase the cost and volume of the equipment owing to the port expansion. In this regard, this article proposes a multiport transformer-less UPFC (MTUPFC) with easy terminal expandability. The decoupled active and reactive power flow are also controlled independently. This device presents several advantages, including low cost, lightweight, fast dynamic response characteristics, and easy port expansion. Therefore, the MTUPFC has significant advantages in power grids with complex configurations and large-scale renewable energy integration. The operation principle and control strategies of the proposed MTUPFC are elaborated. The feasibility and effectiveness of the MTUPFC are verified by a 60-MVA simulation model and a 2.5-kVA scaled-down experimental platform, respectively.

In this study, a new method to reduce the in-band radar cross section (RCS) of a circularly polarized microstrip antenna array (CPMAA) based on a novel feed network is presented, which can independently regulate the radiation and scattering performances without loading metasurface or modifying the shape of the antenna element. Using the principle of the Van Atta antenna, the 180° phase difference between waves reradiated by the adjacent subarrays of the proposed CPMAA is realized by controlling the transmission phase of connected microstrip lines in the feed network; thus, the monostatic RCS is reduced by phase cancellation. Compared with the reference antenna array, the monostatic RCS of the proposed CPMAA is reduced in the frequency band of 3–5.4 GHz under both ${x}$ - and ${y}$ -polarized incident waves. The maximum monostatic RCS reduction value under ${x}$ - and ${y}$ -polarized incident waves is 19.22 and 22.18 dB, respectively. To verify the validation of the proposed method, a prototype is manufactured and its performance measured. The measured results are in good agreement with the simulation ones.

Many signals in the real world are nonlinear and complex, and signal time-frequency analysis has been widely used in many fields. It remains a challenging task to accurately decompose amplitude modulation-frequency modulation (AM-FM) signals with complex variation laws. The existing methods still have room to improve the decomposition accuracy of complex AM-FM signals, such as signals with crossing instantaneous frequency (IF) or close IFs. This article presents a novel sparsity-assisted variational nonlinear component decomposition (SVNCD) for analyzing nonstationary multicomponent signal with complex variation laws. To better restrict the bandwidth of demodulated signal and accurately estimate IF, SVNCD establishes a new sparse optimization model with clear mathematical meaning for the demodulated signal of the original signal, considering the smoothness and Fourier spectrum constraints. Moreover, SVNCD establishes a sparse constraint optimization model on the IF of the signal and its increment, which is capable of effectively extracting the IF variation law of complex signals and addressing the mode aliasing problem. Besides, we build a unified framework for extracting the initial IFs of complex signals with uncrossing or crossing frequency trajectories. The decomposition experiments of various simulated and experimental complicated signals are carried out for verification. The results verify that SVNCD achieves better decomposition accuracy for complex nonstationary multicomponent signals with uncrossing or crossing frequency trajectories than existing signal decomposition and time-frequency transform methods. Moreover, SVNCD could accurately estimate the IF of the original signal and reconstruct the subsignals.

ABSTRACT In order to characterize static and cyclic behavior of high strength structural steels, coupons made of two typical kinds of such steels in China, i.e. Q550 and Q690 steels [...]

Demosaicing is a technique that reconstructs an RGB image from fragmentary color samples sensed by the image sensor. The color filter array (CFA), which is placed over the image sensor, determines the color of each pixel. The most used color filter array is the Bayer CFA. This paper proposes an Anti-Aliasing and Anti-Color-Artifact Demosaicing (AAACA) algorithm for the Bayer pattern and the resource-efficient very-large-scale integration (VLSI) architecture for the proposed algorithm. The AAACA comprises an anti-aliasing approach and a color artifacts filter named color difference-based median filter (CDMF). Compared to the traditional demosaicing methods that equally treat pixels on and not on edges, the AA reconstructs the pixels on edges with different strategies from those not on edges, significantly removing the aliasing around recovered edges. Then the CDMF is utilized to remove the color artifacts of the reconstructed RGB image based on the color difference after median filtering. We respectively simulate the quantitative evaluation and subjective visual quality on McMaster and Kodak datasets. Our experiments reveal that the proposed AAACA algorithm can significantly remove the visual aliasing around recovered edges and greatly reduce color artifacts in demosaiced images compared to the state-of-art demosaicing algorithms. The proposed VLSI architectures can achieve superior visual qualities compared with the previous VLSI implementations under the same process technology conditions with 180nm CMOS technology, an image resolution of $1280\times 720$ (HD), and a working frequency of 200MHz.

With the increasing demand for high-resolution video and real-time processing, the limited efficiency of video-denoising algorithms has become a critical factor. This paper proposes a spatio-temporal video denoising co-processor to suppress an image sequence’s spatial and temporal noise. Temporal denoising is achieved by merging the current and previous frames at the pixel level in which the current frame is processed by a spatial filter. After exploiting noise estimation and motion detection, the Wiener filter calculates the merge ratio. Rather than buffering the entire previous frame, the JPEG-like codec can dynamically adjust the compression ratio through a predefined quantization table to satisfy the designed on-chip storage. The experimental results demonstrate that the spatio-temporal denoising co-processor can effectively eliminate the fluctuation of the grayscale value of the noise in videos. Simultaneously, the adaptive codec can reduce the storage space consumption for the frame buffer by at least 80% of the original size. To the best of our knowledge, this is the first fully integrated spatio-temporal denoising co-processor without any external memory. Additionally, the grayscale, RGB, and RAW versions of the co-processor are also implemented on the Stratix V FPGA platform and synthesized in 28nm CMOS technology.

Soft normally open point (SNOP) is an emerging solution for distributed networks (DNs) to address voltage violation and feeder congestion caused by the increasing integration of distributed energy resources and new types of loads. Based on power electronics, SNOPs can substitute traditional tie switches for power flow regulation, voltage adjustment, and power quality improvement, enhancing the DNs’ controllability and flexibility. Existing SNOPs found in demonstration projects and the literature are generally based on the back-to-back voltage-source converter (VSC). Because it requires more full-power-rating VSCs as the number of connected feeders increases, this solution is uneconomical in multifeeder flexible interconnection scenarios due to the high device cost and volume. Alternatively, this article proposes a series–shunt multiport SNOP (S2-MSNOP) based on a cascaded H-bridge structure and series–shunt arrangement. The proposed topology can easily extend its ports by increasing the number of submodules with small power ratings, reducing the device cost and volume. The operation principles and control strategies of the S2-MSNOP are elaborated. Verifications on both a 1-MVA simulation model and a 3.3-kVA scaled-down experimental platform prove the feasibility and effectiveness of the S2-MSNOP.

Lithium (Li) metal anodes have become an important component of the next generation of high energy density batteries. However, the Li metal anode still has problems such as Li dendrite growth and unstable solid electrolyte interface layer. Herein, we present a functional electrolyte additive (PANHF) successfully synthesized from acrylonitrile and hexafluorobutyl methacrylate via a polymerization reaction. With extensive analytical characterization, it is found that the PANHF can improve the reversibility and Coulombic efficiency of the Li deposition/dissolution reaction and prevent the growth of Li dendrites by forming a solid electrolyte interphase rich in organic matter on the outer layer and LiF on the inner layer. The results show that the cycling performance of the Li/Li cell was greatly improved in the electrolyte containing 0.5 wt % PANHF. Specifically, the cycling stability of more than 700 cycles was achieved at a current density of 1.0 mA cm–2. Moreover, the Li/NCM811 cell with 0.5 wt % PANHF has a higher capacity of 137.7 mA h g–1at 1.0 C and a capacity retention of 83.41% after 200 cycles. This work highlights the importance of protecting the Li metal anode with functional bipolymer additives for next-generation Li metal batteries.

The meshed high-voltage dc network is an effective solution for large-scale new energy consumption and long-distance power transmission. However, when the number of lines is larger than the number of controllable nodes, the converters cannot fully control all line currents. This article proposes a cascaded multilevel embedded dc current flow controller (DCCFC) to increase the dc current flow control freedom in the meshed high-voltage direct current transmission system. It is directly coupled with the main modular multilevel converter (MMC) and maintains power balance through collaborative control. The DCCFC achieves the bidirectional control of dc current flow without an additional power supply or isolation transformer. This article analyzes the working principle of the proposed embedded DCCFC. A power balancing control strategy is proposed with the main MMC and the DCCFC operating in concert. This article also proposes an internal power balancing control strategy considering two circulation optimization methods: common-mode dc voltage injection and q-axis ac voltage injection. The experimental results of the downscaled prototype validate the feasibility and effectiveness of the proposed embedded DCCFC and its control strategy.

The characterization of gene–environment interactions (GEIs) can provide detailed insights into the biological mechanisms underlying complex diseases. Despite recent interest in GEIs for rare variants, published GEI tests are underpowered for an extremely small proportion of causal rare variants in a gene or a region. By extending the aggregated Cauchy association test (ACAT), we propose three GEI tests to address this issue: a Cauchy combination GEI test with fixed main effects (CCGEI-F), a Cauchy combination GEI test with random main effects (CCGEI-R), and an omnibus Cauchy combination GEI test (CCGEI-O). ACAT was applied to combine pvalues of single-variant GEI analyses to obtain CCGEI-F and CCGEI-R and pvalues of multiple GEI tests were combined in CCGEI-O. Through numerical simulations, for small numbers of causal variants, CCGEI-F, CCGEI-R and CCGEI-O provided approximately 5% higher power than the existing GEI tests INT-FIX and INT-RAN; however, they had slightly higher power than the existing GEI test TOW-GE. For large numbers of causal variants, although CCGEI-F and CCGEI-R exhibited comparable or slightly lower power values than the competing tests, the results were still satisfactory. Among all simulation conditions evaluated, CCGEI-O provided significantly higher power than that of competing GEI tests. We further applied our GEI tests in genome-wide analyses of systolic blood pressure or diastolic blood pressure to detect gene–body mass index (BMI) interactions, using whole-exome sequencing data from UK Biobank. At a suggestive significance level of 1.0 × 10−4, KCNC4, GAR1, FAM120AOSand NT5C3Bshowed interactions with BMI by our GEI tests.

Benefiting from high energy density (2,600 Wh kg−1) and low cost, lithium–sulfur (Li–S) batteries are considered promising candidates for advanced energy-storage systems1–4. Despite tremendous efforts in suppressing the long-standing shuttle effect of lithium polysulfides5–7, understanding of the interfacial reactions of lithium polysulfides at the nanoscale remains elusive. This is mainly because of the limitations of in situ characterization tools in tracing the liquid–solid conversion of unstable lithium polysulfides at high temporal–spatial resolution8–10. There is an urgent need to understand the coupled phenomena inside Li–S batteries, specifically, the dynamic distribution, aggregation, deposition and dissolution of lithium polysulfides. Here, by using in situ liquid-cell electrochemical transmission electron microscopy, we directly visualized the transformation of lithium polysulfides over electrode surfaces at the atomic scale. Notably, an unexpected gathering-induced collective charge transfer of lithium polysulfides was captured on the nanocluster active-centre-immobilized surface. It further induced an instantaneous deposition of nonequilibrium Li2S nanocrystals from the dense liquid phase of lithium polysulfides. Without mediation of active centres, the reactions followed a classical single-molecule pathway, lithium polysulfides transforming into Li2S2and Li2S step by step. Molecular dynamics simulations indicated that the long-range electrostatic interaction between active centres and lithium polysulfides promoted the formation of a dense phase consisting of Li+and Sn2−(2 < n≤ 6), and the collective charge transfer in the dense phase was further verified by ab initio molecular dynamics simulations. The collective interfacial reaction pathway unveils a new transformation mechanism and deepens the fundamental understanding of Li–S batteries.

Medium voltage (MV) ac–dc hybrid distribution network attracts much interest due to its high reliability, high power quality, and high compatibility with distributed generation and dc loads. As the key enablers to interconnect ac and dc grids, the converter stations usually adopt the modular multilevel converter (MMC) topology due to its superior modularity and scalability. Unlike the conventional stations that are implemented with multiple MMCs to accommodate multiple ac feeders, a novel multi-ac-port MMC station (MACP-MMC), which evolves from the MMC topology, is proposed in this article to interconnect different ac feeders and facilitate flexible power exchange in the MV hybrid distribution network. In addition to the benefits inherited from the MMC, the proposed MACP-MMC also features easy multiport extension, bidirectional power flow adjustment, high power density, and low cost. The operation principle, energy balance mechanism, and control strategies are elaborated. Finally, its effectiveness is verified by both simulation results in a 3-MVA case and experimental results obtained from a 3-kVA scaled-down lab prototype.

The OEMS was conducted by “operando” mode in industry-scale pouch-type cell with real-time monitoring under practical operation conditions, and the trapped-gas-derived derivative reactions were revealed and investigated.

Ni-rich layered metal oxide cathodes and extreme fast charging (XFC) protocol have been introduced into lithium-ion batteries for the wider adoption of various electric devices. However, nickel intensifies electrolyte decomposition and XFC poses challenges due to extremely high current density. Based on the characterization paradigm established in our previous work, our findings reveal a fundamental difference in the decomposition pathway of the electrolyte under XFC conditions compared to the enhanced reactivity between the oxide and electrolyte caused by Ni content. Specifically, Ni catalyzes solvent dehydrogenation, leading to the formation of protic species that can attack the intermediate, PF5, thereby promoting the decomposition/hydrolysis of LiPF6. But in XFC conditions, the reaction time of dehydrogenation conducted at high voltages is significantly reduced, while conversion of LiPF6to PF5lasts throughout the discharging process. Greater accumulation of PF5as a new initiator changes the solvent decomposition pathway, leading to different cathode–electrolyte interface layers.

A broadband double-layer transmitarray antenna (TA) is proposed in this letter. In order to obtain broadband performance in a double-layer structure, we use a “receiving–transmitting” (RX-TX) structure instead of a double-layer frequency selective surface. The elements of the new TA are composed with metal layers and dielectric substrate. Both the metal layer are connected by a metallized via and etched with orthogonal slots. The RX and TX layers work without interfering while converting the linearly polarized incident wave into orthogonal polarization. Phase compensation can be achieved by changing the direction and length of the microstrip meander ling. Then, a broadband TA is designed. Considering the simplicity of the design, we sequentially selected eight phase states at 45° intervals for phase modulation. The measured maximum antenna gain is 24.5 dBi. The center frequency is 10 GHz. The measured 1 and 3 dB gain bandwidth are 18.7% and 29.4%, respectively. The maximum aperture efficiency is 51%.

The initial Na loss limits the theoretical specific capacity of cathodes in Na-ion full cell applications, especially for Na-deficient P2-type cathodes. In this study, we propose a presodiation strategy for cathodes to compensate for the initial Na loss in Na-ion full cells, resulting in a higher specific capacity and a higher energy density. By employing an electrochemical presodiation approach, we inject 0.32 excess active Na into P2-type Na0.67Li0.1Fe0.37Mn0.53O2(NLFMO), aiming to compensate for the initial Na loss in hard carbon (HC) and the inherent Na deficiency of NLFMO. The structure of the NLFMO cathode converts from P2 to P′2 upon active Na injection, without affecting subsequent cycles. As a result, the HC||NLFMOpreNafull cell exhibits a specific capacity of 125 mAh/g, surpassing the value of 61 mAh/g of the HC||NLFMO full cell without presodiation due to the injected active Na. Moreover, the presodiation effect can be achieved through other engineering approaches (e.g., Na-metal contact), suggesting the scalability of this methodology.

Organophosphate pesticides are used in agriculture due to their high effectiveness and low persistence in eradicating insects and pests. However, conventional detection methods encounter the limitation of undesired detection specificity. Thus, screening phosphonate-type organophosphate pesticides (OOPs) from their analogues, phosphorothioate organophosphate pesticides (SOPs), remains a challenge. Here, we reported a d-penicillamine@Ag/Cu nanocluster (DPA@Ag/Cu NCs)-based fluorescence assay to screen OOPs from 21 kinds of organophosphate pesticides, which can be used for logic sensing and information encryption. Acetylthiocholine chloride was enzymatically split by acetylcholinesterase (AChE) to produce thiocholine, which reduced the fluorescence of DPA@Ag/Cu NCs due to the transmission of electrons from DPA@Ag/Cu NCs donor to the thiol group acceptor. Impressively, OOPs acted as an AChE inhibitor and retained the high fluorescence of DPA@Ag/Cu NCs due to the stronger positive electricity of the phosphorus atom. Conversely, SOPs possessed weak toxicity to AChE, which led to low fluorescence intensity. By setting 21 kinds of organophosphate pesticides as the inputs and the fluorescence of the resulting products as the outputs, DPA@Ag/Cu NCs could serve as a fluorescent nanoneuron to construct Boolean logic tree and complex logic circuit for molecular computing. As a proof of concept, by converting the selective response patterns of DPA@Ag/Cu NCs into binary strings, molecular crypto-steganography for encoding, storing, and concealing information was successfully achieved. This study is expected to advance the progress and practical application of nanoclusters in the area of logic detection and information security while also enhancing the relationship between molecular sensors and the world of information.

Demetalation, caused by the electrochemical dissolution of metal atoms, poses a significant challenge to the practical application of single-atom catalytic sites (SACSs) in proton exchange membrane-based energy technologies. One promising approach to inhibit SACS demetalation is the use of metallic particles to interact with SACSs. However, the mechanism underlying this stabilization remains unclear. In this study, we propose and validate a unified mechanism by which metal particles can inhibit the demetalation of Fe SACSs. Metal particles act as electron donors, decreasing the Fe oxidation state by increasing the electron density at the FeN4position, thereby strengthening the Fe–N bond, and inhibiting electrochemical Fe dissolution. Different types, forms, and contents of metal particles increase the Fe–N bond strength to varying extents. A linear correlation between the Fe oxidation state, Fe–N bond strength, and electrochemical Fe dissolution amount supports this mechanism. Our screening of a particle-assisted Fe SACS led to a 78% reduction in Fe dissolution, enabling continuous operation for up to 430 h in a fuel cell. These findings contribute to the development of stable SACSs for energy applications.