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Metasurfaces based on resonant subwavelength photonic structures enable novel ways of wavefront control and light focusing, underpinning a new generation of flat-optics devices1. Recently emerged all-dielectric asymmetric metasurfaces, composed of arrays of metaunits with broken in-plane inversion symmetry2–7, exhibit high-quality resonances originating from the intriguing physics of bound states in the continuum. Here, we combine dielectric metasurfaces and hyperspectral imaging to develop an ultrasensitive label-free analytical platform for biosensing. Our technique can acquire spatially resolved spectra from millions of image pixels and use smart data-processing tools to extract high-throughput digital sensing information at the unprecedented level of less than three molecules per μm2. We further show spectral data retrieval from a single image without using spectrometers, enabled by our unique sensor design, paving the way for portable diagnostic applications. This combination of nanophotonics and imaging optics extends the capabilities of dielectric metasurfaces to analyse biological entities and atomic-layer-thick two-dimensional materials over large areas.Spatially resolved spectra from millions of pixels and information extraction from three molecules per μm2 is now possible using dielectric metasurfaces.

Long-term stability and high-rate capability have been the major challenges of sodium-ion batteries. Layered electroactive materials with mechanically robust, chemically stable, electrically and ironically conductive networks can effectively address these issues. Herein we have successfully directed carbon nanofibers to vertically penetrate through graphene sheets, constructing robust carbon nanofiber interpenetrated graphene architecture. Molybdenum disulfide nanoflakes are then grown in situ alongside the entire framework, yielding molybdenum disulfide@carbon nanofiber interpenetrated graphene structure. In such a design, carbon nanofibers prevent the restacking of graphene sheets and provide ample space between graphene sheets, enabling a strong structure that maintains exceptional mechanical integrity and excellent electrical conductivity. The as-prepared sodium ion battery delivers outstanding electrochemical performance and ultrahigh stability, achieving a remarkable specific capacity of 598 mAh g −1 , long-term cycling stability up to 1000 cycles, and an excellent rate performance even at a high current density up to 10 A g −1 . Here the authors construct carbon nanofiber interpenetrated graphene architecture with in-situ grown MoS 2 nanoflakes alongside the framework. The design combines exceptional mechanical integrity and excellent electronic conductivity, enabling outstanding electrochemical performance in sodium-ion battery.

Although mid-infrared (mid-IR) spectroscopy is a mainstay of molecular fingerprinting, its sensitivity is diminished somewhat when looking at small volumes of sample. Nanophotonics provides a platform to enhance the detection capability. Tittl et al. built a mid-IR nanophotonic sensor based on reflection from an all-dielectric metasurface array of specially designed scattering elements. The scattering elements could be tuned via geometry across a broad range of wavelengths in the mid-IR. The approach successfully detected and differentiated the absorption fingerprints of various molecules. The technique offers the prospect of on-chip molecular fingerprinting without the need for spectrometry, frequency scanning, or moving mechanical parts. Science , this issue p. 1105 A pixelated dielectric metasurface is used for the mid-infrared detection of molecular fingerprints. Metasurfaces provide opportunities for wavefront control, flat optics, and subwavelength light focusing. We developed an imaging-based nanophotonic method for detecting mid-infrared molecular fingerprints and implemented it for the chemical identification and compositional analysis of surface-bound analytes. Our technique features a two-dimensional pixelated dielectric metasurface with a range of ultrasharp resonances, each tuned to a discrete frequency; this enables molecular absorption signatures to be read out at multiple spectral points, and the resulting information is then translated into a barcode-like spatial absorption map for imaging. The signatures of biological, polymer, and pesticide molecules can be detected with high sensitivity, covering applications such as biosensing and environmental monitoring. Our chemically specific technique can resolve absorption fingerprints without the need for spectrometry, frequency scanning, or moving mechanical parts, thereby paving the way toward sensitive and versatile miniaturized mid-infrared spectroscopy devices.

Huygens’ metasurfaces demonstrate almost arbitrary control over the shape of a scattered beam; however, its spatial profile is typically fixed at the fabrication time. The dynamic reconfiguration of this beam profile with tunable elements remains challenging, due to the need to maintain the Huygens’ condition across the tuning range. In this work, we experimentally demonstrate that a time-varying metadevice which performs frequency conversion can steer transmitted or reflected beams in an almost arbitrary manner, with fully dynamic control. Our time-varying Huygens’ metadevice is made of both electric and magnetic meta-atoms with independently controlled modulation, and the phase of this modulation is imprinted on the scattered parametric waves, controlling their shapes and directions. We develop a theory which shows how the scattering directionality, phase, and conversion efficiency of sidebands can be manipulated almost arbitrarily. We demonstrate novel effects including all-angle beam steering and frequency-multiplexed functionalities at microwave frequencies around 4 GHz, using varactor diodes as tunable elements. We believe that the concept can be extended to other frequency bands, enabling metasurfaces with an arbitrary phase pattern that can be dynamically tuned over the complete2πrange.

A potential non-precious metal catalyst for oxygen reduction reaction should contain metal-N 4 moieties. However, most of the current strategies to regulate the distances between neighboring metal sites are not pre-designed but depend on the probability by tuning the metal loading or the support. Herein, we report a general method for the synthesis of neighboring metal-N x moieties (metal = Fe, Cu, Co, Ni, Zn, and Mn) via an interfacial-fixing strategy. Specifically, polydopamine is used to coat nanotemplates made of metal oxides, followed by pyrolysis to form a metal-oxide skeleton coated by rich nitrogen-doped carbon shells. After chemically etching the skeleton, only interfacial metal atoms strongly bonded with the support via nitrogen atoms are retained. The high purity (>95%) of dual Fe sites was confirmed by both the direct visualization of local regions and the indirect evidence of the averaged information. When these neighboring metal-N x moieties are applied for oxygen reduction reaction, Fe-N x moieties exhibit the superior activity, even outperforming commercial Pt/C in the aspects of the half-wave potential, methanol tolerance, carbon monoxide tolerance, and robustness. Generic synthesis of metal-N4 moieties is interesting but challenging. Here the authors report an interfacial-fixing strategy to prepare neighboring metal-N4 sites, such as Fe2-N6, for oxygen reduction reaction.

Developing efficient and economical electrocatalysts for acidic oxygen evolution reaction (OER) is essential for proton exchange membrane water electrolyzers (PEMWE). Cobalt oxides are considered promising non-precious OER catalysts due to their high activities. However, the severe dissolution of Co atoms in acid media leads to the collapse of crystal structure, which impedes their application in PEMWE. Here, we report that introducing acid-resistant Ir single atoms into the lattice of spinel cobalt oxides can significantly suppress the Co dissolution and keep them highly stable during the acidic OER process. Combining theoretical and experimental studies, we reveal that the stabilizing effect induced by Ir heteroatoms exhibits a strong dependence on the distance of adjacent Ir single atoms, where the OER stability of cobalt oxides continuously improves with decreasing the distance. When the distance reduces to about 0.6 nm, the spinel cobalt oxides present no obvious degradation over a 60-h stability test for acidic OER, suggesting potential for practical applications. Dissolution of Co atoms in acidic media impedes the application of cobalt oxides in proton exchange membrane water electrolyzers. Here, the authors reveal a stabilizing effect induced by Ir single atoms on cobalt oxides that suppress Co dissolution.

The soluble nature of polysulfide species created on the sulfur electrode has severely hampered the electrochemical performance of lithium-sulfur （Li-S） batteries. Trapping and anchoring polysulfides are promising approaches for overcoming this issue. In this work, a mechanically robust, electrically conductive hybrid carbon aerogel （HCA） with aligned and interconnected pores was created and investigated as an interlayer for Li-S batteries. The hierarchical cross-linked networks constructed by graphene sheets and carbon nanotubes can act as an ＂internet＂ to capture the polysulfide, while the micro- and nano-pores inside the aerogel can facilitate quick penetration of the electrolyte and rapid transport of lithium ions. As advantages of the unique structure and excellent accommodation of the volume change of the active materials, a high specific capacity of 1,309 mAh.g-1 at 0.2 C was achieved for the assembled Li-S battery, coupled with good rate performance and long-term cycling stability （78% capacity retention after 600 cycles at 4 C）.

As foundational infrastructure for spatiotemporal information, the Global Navigation Satellite System (GNSS) delivers high-precision positioning, navigation, and timing (PNT) services worldwide. However, satellite atomic clock drift causes satellite clock bias, degrading PNT service quality. Compared to post-processed clock bias products and real-time estimation, satellite clock bias prediction offers a key advantage: it provides high-precision real-time clock bias even in scenarios with limited real-time data or poor communication. Through analysis and summarization of error sources in prediction models, this paper proposed generalized modeling frameworks for both classical and AI-based approaches. We reviewed current research on classical mathematical models—including polynomial, grey, Kalman filter, and time series models—and AI-based models such as machine learning (ML), multilayer perceptron (MLP), recurrent neural networks (RNN), and Transformer architectures. Technical characteristics, applicability, and limitations of each model were discussed. While AI-based models demonstrate superior flexibility and adaptability in complex scenarios compared to classical approaches, they require extensive datasets and computational resources. In conclusion, we summarized the advantages, disadvantages, and future research directions, offering insights for developing next-generation real-time high-precision GNSS PNT services.

In order to solve the problem of coordinated development among mining economy, social governance and environmental conservation in global resource-based cities, we choose Guangxi Zhuang Autonomous Region as the research area. The advantage of resource endowment and resource industry was measured by location quotient and input-output method. The panel data related to mining governance from 2010 to 2021 were selected to build the evaluation and coupling analysis model between mining economic, social governance and environmental conservation, and the spatial-temporal heterogeneity and coupling effect of them were analyzed by comprehensive empowerment evaluation, spatial autocorrelation analysis and barrier degree methods. The results show that: (1) Except for the overall upward trend of social governance, the development level of mining economy and environmental conservation are basically stable; (2) The resource-rich areas have obvious mining economic advantages, and the central cities have good social governance capabilities, and the environmental conservation effectiveness is uncertain; (3) The coupling effect between mining economy and social governance is stronger than that between mining economy and environment conservation, and the synergistic coupling effect of the three is relatively random. Finally, we put forward some policy response strategies to Guangxi, and theoretical and practical reference would be provided for resource-based cities around the world.

Renewable biomass serves as a cost-effective source of carbon matrix to carry single-atom catalysts (SACs). However, the natural abundant oxygen in these materials hinders the sufficient dispersion of element with high oxygen affinity such iron (Fe). The lowered-density and oxidized SACs greatly limits their catalytic applications. Here we develop a facile continuous activation (CA) approach for synthesizing robust biomass-derived Fe-SACs. Comparing to the traditional pyrolysis method, the CA approach significantly increases the Fe loading density from 1.13 atoms nm −2 to 4.70 atoms nm −2 . Simultaneously, the CA approach induces a distinct coordination tuning from dominated Fe-O to Fe-N moieties. We observe a pH-universal oxygen reduction reaction (ORR) performance over the CA-derived Fe-SACs with a half-wave potential of 0.93 V and 0.78 V vs. RHE in alkaline and acidic electrolyte, respectively. Density functional theory calculations further reveal that the increased Fe-N coordination effectively reduces the energy barriers for the ORR, thus enhancing the catalytic activity. The Fe-SACs-based zinc-air batteries show a specific capacity of 792 mA·h·g Zn −1 and ultra-long life span of over 650 h at 5 mA cm −2 . Developing efficient single-atom catalysts for clean energy technologies is still challenging. Here, the authors report a facile method to increase the density and tune the coordination of iron atom loaded in single-atom catalysts that boosts the activity for pH-universal oxygen electrolysis.