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On the heels of orthogonal time frequency space (OTFS) modulation, the recently discovered affine frequency division multiplexing (AFDM) is a promising waveform for the sixth-generation wireless network. In this paper, we study the widely-used embedded pilot-aided (EPA) channel estimation in multiple-input multiple-output AFDM (MIMO-AFDM) system with fractional Doppler shifts. We first formulate the vectorized input-output relationship of MIMO-AFDM, and theoretically prove that MIMO-AFDM can achieve full diversity in doubly selective channels. Then we illustrate the implementation of EPA channel estimation in MIMO-AFDM and unveil that serious inter-Doppler interference (IDoI) occurs if we try to estimate the channel gain, delay shift, and Doppler shift of each propagation path. To address this issue, the diagonal reconstructability of AFDM subchannel matrix is studied and a low-complexity embedded pilot-aided diagonal reconstruction (EPA-DR) channel estimation scheme is proposed. The EPA-DR scheme calculates the AFDM effective channel matrix directly without estimating the three channel parameters, eliminating the severe IDoI inherently. Since the effective channel matrix is necessary for MIMO-AFDM receive processing, we believe this is an important step to bring AFDM towards practical communication systems. Simulation results validate the effectiveness of the proposed EPA-DR scheme.

The split energy storage-embedded modular multilevel converter has emerged as a promising solution to address energy efficiency and power quality concerns in electrified railways. However, the intricate system topology and coupled control objectives of the existing ones aggravate the reliability and flexibility. To address these challenges, a star-connection supercapacitor-embedded cascaded H-bridge multilevel converter (SCCHMC) STATCOM is proposed in this article. The proposed configuration offers advantages as it requires fewer power cells, enhancing reliability while reducing costs. To facilitate the flexible control of multiobjective, including regenerative braking energy utilization, negative sequence current suppression, and reactive compensation, a sequence components-based decoupling control is developed for the SCCHMC-STATCOM. The proposed method features straightforwardness and flexibility, with its effectiveness validated through experimental results. Additionally, a comprehensive discussion regarding fault protection and a comprehensive comparison between the proposed SCCHMC-STATCOM and the state-of-the-art energy storage-based solution for railway applications are conducted.

Adhesives that can in situ adhere to substrates and long-term maintain robust adhesion at extremely low temperatures are highly desired in fields such as aerospace, polar regions, and biological industries. Unfortunately, developing such adhesives has been a daunting task so far, as most polymers tend to freeze in such an environment, leading to poor interfacial wetting, serious deformation, and significant fragileness. To address this challenge, a series of poly(dimethylsiloxane)-based polyurea adhesives were synthesized through a non-isocyanate route. This adhesive exhibited exceptional segmental dynamics and toughness at extremely low temperatures, as demonstrated by the continuous evolution of ordered and disordered hydrogen bonds associated with C═O until the test limit of −170 °C and unprecedented bendability in liquid nitrogen (LN, −196 °C). It could adhere firmly and reversibly to various substrates in LN, achieving an in situ adhesion strength of as high as 1.6 MPa on steel. Evenly important, this adhesive exhibited outstanding long-term tolerance in LN with an ultrahigh adhesion strength of 18.3 MPa after 30 days of immersion. Surprisingly, long-persistent phosphorescence lasting for ∼7s was also observed in LN. This study reduced the adhesion temperature of adhesives to −196 °C while enhancing the in situ adhesion strength in LN to the MPa level.

Rate splitting multiple access (RSMA) empowered simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided networks have been extensively researched to enhance spectrum efficiency and coverage capability without considering eavesdropping. However, the 360° service coverage provided by STAR-RIS inevitably leads to comprehensive eavesdropping, posing more significant security risks for private information transmission compared to traditional reflection-only RIS. In this letter, we propose a secure transmission scheme for STAR-RIS aided downlink communication systems, which is empowered by a novel multiple access paradigm called RSMA. To address the security challenge, we study the proposed security transmission scheme by jointly designing active beamforming, passive beamforming, and common rate allocation to maximize the sum secrecy rate. To tackle the highly coupled non-convex optimization problem, we propose an efficient and low-complexity successive convex approximation-based penalization RSMA-STAR (PE-RSSTA) algorithm. The numerical results demonstrate that: i) the algorithm converges through iterations; ii)the proposed algorithm improves secrecy rate performance by 5.22% compared to the PE space division multiple access (SDMA) STAR algorithm and achieves a notable 27.37% improvement over the conventional RIS algorithm.

The synergistic effect of pre-intercalated Mn2+and H2O enlarge the interlayer spacing and improve the stability of MVOH for aqueous zinc-ion batteries. Zn2+/H+co–(de)intercalation mechanism is also validated through in-situ and ex-situ characterizations.

We propose and experimentally demonstrate a spatial-light-modulator (SLM) based optical wireless communication (OWC) system using non-orthogonal multiple access realizing four-layer of successive interference cancellation (SIC) iterations for the first time. This can be attributed by our two contributions. First, an iterative phase correction algorithm (PCA) is proposed for addressing the SLM non-ideal effects. Second, low-density parity check is utilized to provide coding gain for the SIC. Experimental results show that 3.5-dB improvement at a steering angle of (5o, 5o) is achieved by the PCA, and >54-Gbps total data rate is achieved in the 4-user OWC system.

The advent of wearable sensors heralds a transformation in the continuous, noninvasive analysis of biomarkers critical for disease diagnosis and fitness management. Yet, their advancement is hindered by the functional challenges affiliated with their active sensing analysis layer. Predominantly due to suboptimal intrinsic material properties and inconsistent dispersion leading to aggregation, thus compromising sensor repeatability and performance. Herein, an innovative approach to the functionalization of wearable electrochemical sensors was introduced, specifically addressing these limitations. The method involves a proton-induced self-assembly technique at the organic–water (O/W) interface, facilitating the generation of biomarker-responsive films. This research offers flexible, breathable sensor capable of real-time precision tracking l-cysteine (l-Cys) precision tracking. Utilizing an activation mechanism for Prussian blue nanoparticles by hydrogen peroxide, the catalytic core exhibits a specific response to l-Cys. The implications of this study refine the fabrication of film-based analysis electrodes for wearable sensing applications and the broader utilization of two-dimensional materials in functional-specific response films. Findings illuminate the feasibility of this novel strategy for precise biomarker tracking and extend to pave the way for constructing high-performance electrocatalytic analytical interfaces.

The effective transmission of signals from high-temperature sensors in harsh environments is crucial in aerospace applications. However, the rapid fabrication of thin/thick film conductive lines (TFCLs) while avoiding damage to the substrate and minimizing disturbance remains challenging. Here, we present a strategy for the direct conformal printing of silver-palladium (AgPd) TFCLs, enabling the stable lead-out of signals from high-temperature sensors across corners without drilling the substrate, solving the problem of traditional perforated leads damaging the substrate structure. The fabricated AgPd TFCL exhibits excellent electrical performance with a low-temperature coefficient of resistance (TCR) of 197 ppm/°C (from 200 °C to 800 °C) and high long-term stability, as evidenced by a resistance drift rate (DR) of 0.71%/h (during 24 h of isothermal aging at 800 °C). Furthermore, the TFCL demonstrates outstanding scouring resistance, high bond strength, and exceptional process compatibility. As a proof of concept, a high-temperature probe was prepared, and cross-corner TFCLs enabled the nondestructive extraction of signals from a resistance temperature detector (RTD), spanning from the front to the back of the substrate. This technology establishes a foundation for signal lead-outs from sensors on specially shaped curved surfaces in extreme environments.

This letter explores potential of a segment anything model (SAM), the first promptable image segmentation system, in detecting wireless interference based on time-frequency images (TFI). Since the original SAM is pre-trained with natural images, it struggles to segment interferences within bandwidth of legitimate communication signals. To address this, we propose a novel prompting and tuning enhanced SAM to effectively segment in-band interferences, especially in the presence of blurred boundaries on TFIs. We first exploit the difference in single-channel luminance among gray-scaled TFI pixels and propose a mean shift clustering on this basis which helps to prompt the interference regions for segmentation. Then the lightweight mask decoder of SAM is fine-tuned using an augmented dataset containing the refined examples of in-band interferences. Compared to the state-of-the-art, experiments show that the proposed method significantly improves the segmentation accuracy as indicated by dice coefficients and intersection-over-union in a wide rang of jamming-to-signal ratio.

F-44 phenolic epoxy fibers were produced through high-temperature dry spinning utilizing F-44 phenolic epoxy resin as the base material, combined with n-butanol and ethylenediamine (EDA) as the curing agent. The fibers were subsequently analyzed for their structural, thermal stability, microstructural, and mechanical properties using techniques such as Fourier transform infrared spectroscopy, micro-infrared imaging, thermogravimetric analysis, nuclear magnetic resonance, scanning electron microscopy, and fiber strength testing. The limitations of phenolic resins, including high brittleness, poor toughness, and low elongation at break, restrict their potential applications, necessitating modifications to broaden their utility. Research findings indicate that modifying EDA induces a ring-opening reaction of epoxy groups, thereby enhancing the resin’s structure and improving the thermal stability and mechanical properties of fibers. The thermal stability and mechanical strength of the fibers were optimized at an EDA concentration of 2.0 wt% and curing time of 30 min, resulting in a tensile strength of 105 MPa and an elongation at break of 27.6 %.

[Display omitted] • SCC and RM are synergistic treated by hydrothermal acid-leaching. • Thermodynamic calculation reveals the synergistic leaching mechanism. • The leaching rates of Fe and Al increased by 7.01 % and 8.66 %, respectively, compare with that of RM alone. • The activation energies of Al and Fe are 21.52 kJ/mol and 2.82 kJ/mol, respectively. Spent carbon cathode (SCC) and red mud (RM) are two kinds of solid wastes that are harmful to the environment and rich in valuable components from the aluminum industry. In this study, the valuable components of SCC and RM are co-treated by the hydrothermal acid-leaching. The synergistic treatment process is analyzed by phase characterization, thermodynamic calculation, single factor experiment, orthogonal experiment and kinetic study. The results show that the leaching of impurities by the synergistic treatment is better than that of hydrothermal acid-leaching alone. Under the optimal leaching conditions (liquid–solid ratio of 25 mL/g, temperature of 453 K, time of 270 min and acid concentration of 4 mol/L), the leaching efficiency of aluminum and iron reaches 89.70 % and 87.91 %, respectively. For aluminum, the time is the key factor affecting its leaching, the activation energy is 21.52 kJ/mol, and the leaching process is controlled by chemical reaction and solid product layer diffusion. For iron, the acid concentration is the key factor affecting its leaching, the activation energy is 2.82 kJ/mol, and the leaching process is controlled by the solid product layer diffusion. The leaching residue obtain by synergistic hydrothermal acid-leaching is C and SiO 2. This process provides a new solution for the treatment and recovery of SCC and RM. [ABSTRACT FROM AUTHOR]

Graphical Abstract:

The shrinkage and collapse of wood cell walls during carbonization make it challenging to control the size and shape of carbonized wood (CW) through pre- or postprocessing (e.g., sawing, cutting, and milling). Herein, a shape-adaptive MXene shell (MS) is created on the surface of the wood cell walls. The MS limits the deformation of wood cell walls by spatial confinement and traction effects, which is supported by the inherent dimensional stability of the MS and the formation of new C–O–Ti covalent bonds between the wood cell wall and MS. Consequently, the volumetric shrinkage ratio of CW encapsulated by the MS (CW-MS) is significantly reduced from 54.8% for CW to 2.6% for CW-MS even at 800 °C. The harnessing of this collapse enables the production of CW-MS with prolonged stability and high electric conductivity (384 S m–1). These properties make CW-MS suitable for energy storage devices with various designed shapes, matching the increasingly compact and complex structures of electronic devices.

In this work, we employed a one-step hydrothermal method, assisted by PVP and LAA additives, to synthesize NiFe-LDH@Ti3C2Txin situ with a three-dimensional network structure. The crumpled NiFe-LDH nanoflakes were anchored on the Ti3C2Txsurface in close face-to-face contact by heterogeneous nucleation and growth with oxygen-containing functional groups as active sites. More importantly, an oxygen bridge was simultaneously formed at the interface between NiFe-LDH and Ti3C2Tx, which, as an electron migration channel to form a connected conductive network, significantly enhanced the structural stability and electron migration rate. Meanwhile, the open 3D network (SBET: 125.6 m2g–1) facilitates the exposure of active sites and accelerates the ion migration rate, leading to excellent diffusion kinetics. As a consequence, NiFe-LDH@Ti3C2Txdemonstrates outstanding electrochemical stability as an anode for LIBs (987 mAh g–1at 0.5 A g–1up to 200 cycles and 912 mAh g–1at 1 A g–1up to 600 cycles) and SIBs (280 mAh g–1at 0.5 A g–1up to 200 cycles and 211 mAh g–1at 1 A g–1up to 2000 cycles).

The morphological features of materials significantly influence their interactions with cells, consequently affecting the cellular uptake of these materials. In this study, we examine the cellular uptake behavior of spherical metal–organic frameworks (MOFs) and petaloid MOFs, both possessing similar sizes and compositions. In comparison to spherical MOFs, dendritic cells (DCs) and macrophages exhibit superior phagocytic uptake of petaloid MOFs. Next, the results demonstrate that R848@petaloid MOFs more effectively promote the repolarization of tumor-associated macrophages (TAMs) from the M2 to M1 phenotype and the maturation of DCs. More importantly, the R848-loaded petaloid MOFs are found to significantly enhance the therapeutic effects of radiotherapy (RT) by eliciting antitumor responses. Furthermore, R848@petaloid MOFs combined with RT and αPD-L1 elicit a potent abscopal effect, effectively suppressing tumor metastasis. Therefore, this work proposes a new strategy to enhance the uptake of immunomodulators by immune cells through modulating the morphology of drug delivery carriers.

Hierarchical biobased micro/nanomaterials offer great potential as the next-generation building blocks for robust films or macroscopic fibers with high strength, while their capability in suppressing crack propagation when subject to damage is hindered by their limited length. Herein, we employed an approach to directly convert bulk wood into fibers with a high aspect ratio and nanosized branching structures. Particularly, the length of microfibers surpassed 1 mm with that of the nanosized branches reaching up to 300 μm. The presence of both interwoven micro- and nanofibers endowed the product with substantially improved tensile strength (393.99 MPa) and toughness (19.07 MJ m–3). The unique mechanical properties arose from mutual filling and the hierarchical deformation facilitated by branched nanofibers, which collectively contributed to effective energy dissipation. Hence, the nanotransformation strategy opens the door toward a facial, scalable method for building high-strength film or macroscopic fibers available in various advanced applications.

MXenes, represented by Ti3C2Tx, have been widely studied in the electrochemical energy storage fields, including lithium-ion batteries, for their unique two-dimensional structure, tunable surface chemistry, and excellent electrical conductivity. Recently, Nb2CTx, as a new type of MXene, has attracted more and more attention due to its high theoretical specific capacity of 542 mAh g–1. However, the preparation of few-layer Nb2CTxnanosheets with high-quality remains a challenge, which limits their research and application. In this work, high-quality few-layer Nb2CTxnanosheets with a large lateral size and a high conductivity of up to 500 S cm–1were prepared by a simple HCl-LiF hydrothermal etching method, which is 2 orders of magnitude higher than that of previously reported Nb2CTx. Furthermore, from its aqueous ink, the viscosity-tunable organic few-layer Nb2CTxink was prepared by HCl-induced flocculation and N-methyl-2-pyrrolidone treatment. When using the organic few-layer Nb2CTxink as an additive-free anode of lithium-ion batteries, it showed excellent cycling performance with a reversible specific capacity of 524.0 mAh g–1after 500 cycles at 0.5 A g–1and 444.0 mAh g–1after 5000 cycles at 1 A g–1. For rate performance, a specific capacity of 159.8 mAh g–1was obtained at a high current density of 5 A g–1, and an excellent capacity retention rate of about 95.65% was achieved when the current density returned to 0.5 A g–1. This work presents a simple and scalable process for the preparation of high-quality Nb2CTxand its aqueous/organic ink, which demonstrates important application potential as electrodes for electrochemical energy storage devices.