Search Results (478)

Achieving both universality and robustness in smart sensing remains a central yet unresolved challenge. Herein, we move beyond the conventional dichotomy of selective versus cross-sensitive sensors by demonstrating their synergistic integration within differential sensing architectures. Optical micro- and nanoparticle-based sensors—both selective (UW) and cross-sensitive (WUT)—were rationally combined to construct information-rich sensing arrays. Performance enhancement was explored considering three complementary strategies: the reduction of inter-sensor redundancy, the exploitation of full spectral fingerprints and multimode optical readout. Across independent datasets, log F analysis uncovered pronounced context-dependent chemosensitive particle behavior, enabling the identification of task-specific leading nanostructures while confirming metric robustness. Full-spectrum chemometric modeling delivered consistently high classification accuracy without overfitting, where SVM-DA excelled in resolving complex multiclass problems. Collectively, this work establishes a generalizable framework for engineering adaptive, high-dimensional sensing platforms, advancing the design of next-generation smart analytical systems, including smart noses and smart tongues. Full article

To address brine discharge pipe blockage caused by salt crystallization in natural gas storage facilities within salt caverns, this study employed GROMACS molecular dynamics simulations to develop a three-dimensional regulatory model integrating interfacial polarity, roughness, and diffusion fields. By constructing and comparing four representative interface models, rough iron, smooth iron, epoxy resin, and polytetrafluoroethylene interfaces in sodium chloride solution, the study systematically revealed the coupled microscopic mechanisms of ion adsorption, diffusion, and ordering. The rough iron interface exhibits a nanotrapping effect, increasing the sodium ion concentration to 3.8 times that of the bulk solution. In contrast, the epoxy resin interface forms a hydrated buffer layer, thereby reducing adsorption energy. Conversely, the PTFE interface exhibits superior anti-crystallization performance, extending the induction period by 3.2 times through synergistic effects of ultra-low adsorption energy, high diffusion coefficient, and weak interfacial tension. By integrating these key parameters, an innovative interfacial anti-crystallization index was established, exhibiting a significant negative correlation with crystallization mass in experiments. Furthermore, a nanostructure modification strategy featuring nano-pore arrays was proposed. This approach reduces effective adsorption sites while enhancing ion diffusion rates, thereby decreasing crystallization rates. Such atomically precise control offers novel pathways for designing advanced anti-crystallization coatings. Full article

This paper proposes an engineering-oriented inverse-design framework to engineer metasurface nanostructures for ultra-broadband electromagnetic absorption over 0.36–10.36 μm. The framework integrates a genetic algorithm (GA) with finite difference time domain (FDTD) simulation and uses a composite objective function combining full-spectrum average reflectance and absorptivity standard deviation to balance absorption level and spectral uniformity. Three strategies, namely dynamic elitist preservation, fitness reuse, and diversified candidate expansion, are introduced to improve the search ability, reduce redundant FDTD evaluations, and retain multiple engineering-relevant candidate solutions. The optimized structure exhibits an average absorptivity of 90.9%, a standard deviation of 0.054, a coefficient of variation of 0.059, a deviation of 0.044, and a Relative Deviation of 0.049. The absorber also maintains robust performance under different polarization states and oblique incidence; over 0–55°, the average absorptivity is 88.9% for TE polarization and 92.5% for TM polarization, with an overall unpolarized average absorptivity of 90.7%. These results demonstrate a design workflow that extends GA inverse design from searching for a single minimum-fitness structure toward engineering-oriented multi-criteria candidate selection. Full article

Surface-enhanced Raman scattering is highly promising for trace molecular detection but requires substrates with both ultrahigh sensitivity and macroscopic uniformity. Current bimetallic nanostructures struggle to achieve large-area structural reproducibility and high-density “hot spots” due to the lack of precise spatial control over nanoparticle arrangement and the random distribution of nanogaps, which severely limits their quantitative reliability in realistic applications. Here, we developed a simple and scalable method to fabricate a highly ordered Au/Ag composite nanoshell array via combining the gas–liquid interface self-assembly and ion sputtering. This prepared substrate is featured by abundant nanoscale openings, crevices, and interfacial junctions. The Au/Ag composite nanoshell array achieves an ultra-low limit of 10⁻¹¹ M for the standard probe Rhodamine 6G. The highly ordered array also ensures advanced large-area signal reproducibility with a relative standard deviation of 6.1%. This work successfully balances the large-area uniformity and high sensitivity in SERS detection. It also provides a robust and reliable plasmonic platform for practical food safety analysis and environmental monitoring. Full article

Resistive random-access memory (RRAM) has emerged as one of the most promising device platforms for neuromorphic, in-memory computing because its two-terminal metal–insulator–metal (MIM) structure can reproduce the weight-update behavior of biological synapses while remaining compatible with mainstream CMOS processing. This review summarizes the current state of RRAM-based neuromorphic technology from four complementary perspectives: device physics, materials, fabrication processes, and packaging. We first describe the operating principles of filamentary and interface-type RRAM, including the forming/set/reset switching sequence, and the two dominant analytical frameworks used to describe the reset transition—the ion-migration model and the thermally driven filament-dissolution model. We then review the switching-layer and electrode materials that have been most widely investigated such as HfO_x, TiO_x, TaO_x, ZnO, ZrO₂, and Cu/Ag-based conductive-bridge systems, together with representative bilayer and doped architectures reported for synaptic devices. The biological functions that RRAM can emulate are discussed alongside the non-ideal characteristics that currently limit on-chip training accuracy, with emphasis on separating device-to-device from cycle-to-cycle variability and on the workload-dependent nature of endurance and retention requirements. We further summarize the process technologies used to integrate RRAM into large-scale, CMOS-compatible arrays, including atomic layer deposition, interfacial oxygen-reservoir engineering, low-thermal-budget back-end-of-line integration, and three-dimensional vertical RRAM patterning, and discuss the advanced packaging strategies such as 2.5D/3D heterogeneous integration, chiplet architectures, thermal-interface materials, and nanostructured underfills required to manage the power density and interconnect demands of large synaptic arrays, distinguishing solutions that have been demonstrated specifically for RRAM neuromorphic arrays from those that remain general advanced-packaging concepts. Finally, RRAM is benchmarked against competing emerging non-volatile memories, and the key research directions such as three-terminal memtransistor architectures, three-dimensional integration with high-performance selectors, and hardware–algorithm co-design that will determine whether RRAM-based neuromorphic hardware can move from laboratory demonstrations to on-device AI, autonomous systems, and large-scale artificial-neural-network accelerators are outlined. Relative to prior reviews that focus primarily on RRAM device physics or on switching-layer materials in isolation, the distinctive contribution of this review is an explicit, cross-layer synthesis that connects device-level non-idealities to their consequences for wafer-scale process integration and for advanced 2.5D/3D packaging—a combination that, to our knowledge, has not been jointly treated in the recent review literature on RRAM-based neuromorphic hardware. Full article

Strict monitoring of methane (CH₄) during underground coal mining is necessary, as the lower explosive limit (LEL) is 5 vol% in air. A conventional tin oxide (SnO₂)-based metal–oxide semiconductor (MOS) sensor has an operating temperature of 200–400 °C, which requires a prohibitive power demand and entails the risk of ignition within an intrinsically safe environment. The decoration of SnO₂ nanoarchitectures with palladium has been demonstrated to achieve room temperature (RT) detection of CH₄ due to the chemical sensitisation spillover mechanism and electronic sensitisation by Schottky barrier modulation. Moreover, palladisation of SnO₂ nanowires (NWs) is likely to be an effective route for achieving a more efficient detection of CH₄ aerosol at RT or near RT. The purpose of this mini-review is to provide a critical synthesis of advances that have been reported between 2020 and 2026. Because no published study to date has directly demonstrated room-temperature CH₄ detection using pure Pd-decorated SnO₂ nanowires, performance data from mechanistically analogous systems—namely H₂-sensing Pd–SnO₂ nanowires and CH₄-sensing non-nanowire Pd–SnO₂ nanostructures—are included in this review and are explicitly labelled as such throughout. This absence of direct RT CH₄ NW data constitutes the primary research gap motivating this review. The performance of Pd-containing SnO₂ nanostructures reported in the literature spans response values of 17.6 (300 ppm CH₄, 2.5 mol% Pd–SnO₂ nanoporous, 340 °C) to 21.3 (3000 ppm CH₄, bimetallic Pt–Pd–SnO₂ mesoporous, 400 °C), representing a 3–10× improvement over bare SnO₂ (response: 2–10 in the same concentration range). These benchmarks were obtained at elevated temperatures (340–400 °C); no equivalent room-temperature CH₄ detection data for Pd–SnO₂ nanowires currently exists in the published literature. Reported response times range from 3 to 9 s at elevated temperature (340–400 °C) to 74–78 s for room-temperature visible-light-activated systems, where photocatalytic oxygen activation is the rate-limiting step. The 30 s MSHA alarm threshold is met by elevated-temperature systems but remains a challenge for RT configurations. The LODs were 175.9 ppb (bimetallic PdxPt/SnO₂ mesoporous system). Two hybrid composites containing rGO exhibited an extended capability for RT operation. Bimetallic PdPt decoration and ML-augmented sensor arrays are identified as the most promising near-term pathways to bridge the selectivity and stability gaps for certified mining deployment. Full article

Self-assembled artificial nanostructures, such as DNA origami, have attracted interest as templates for the placement of inorganic materials because their design enables the incorporation of binding sites for attaching nanocomponents with nanometer-scale precision. In this work, we introduce a lithographically defined window-array substrate as an addressable platform for dark-field spectroscopic studies of individual DNA-origami-templated metallic nanostructures. The pattern was designed using the Nanometer Pattern Generation System (NPGS) software and written by electron beam lithography (EBL) on a SiO_x/Si substrate. The role of the EBL pattern is to provide spatially separated measurement sites that facilitate the localization, selection, and optical interrogation of single-particle and dimer configurations. Metallic nanostructures created by the DNA origami technique, with programmable placement of spherical gold nanoparticles (Au NPs), are used here. The nanostructures are rectangular, measuring 70 nm × 90 nm, with an Au NP attached at one corner or at two opposite corners. These seed NPs are later enlarged by controlled coalescence via electroless silver deposition. Localized surface plasmon resonance (LSPR) studies by dark-field microscopy (DFM) are presented as a proof-of-concept application for evaluating the scattering response of individual silver-metalized nanoparticles and dimers. Full article

Plasmonic nanostructures offer a practical solution for solar-to-thermal conversion, yet simultaneously achieving ultra-broadband absorption, scalable fabrication, and long-term stability using earth-abundant aluminum remains difficult. In this work, we present a three-dimensional (3D) crown-like aluminum nanostructure absorber that achieves an experimental average absorption of 92% across the solar spectrum (200–2500 nm), with only 1.9% degradation in average absorption over 24 months. The structure is fabricated via a scalable anodic aluminum oxide (AAO) template-assisted method, enabling large-area production without costly lithography and exhibiting broad fabrication tolerance to deposition-thickness variations. Electromagnetic simulations and structure analysis reveal that the ultra-broadband absorption arises from three synergistic mechanisms: multi-mode electric resonances, magnetic resonance behavior within the metal–dielectric–metal architecture, and a graded-refractive-index profile. Proof-of-concept photothermal experiments under simulated sunlight offer experimental confirmation of the absorber’s solar-to-thermal conversion capability, showing substantially enhanced solar-to-thermal energy utilization compared to pure-water references. This work provides a scalable, durable, and cost-effective platform for ultra-broadband solar absorption and solar-to-thermal conversion, and offers a viable design strategy for plasmonic absorbers based on earth-abundant materials. Full article

The critical binding of quantum states in Screened Coulomb Potentials such as Yukawa/Debye, Hulthén, and ECSC (Exponential Cosine Screened Coulomb) potentials is of perennial interest and relevance in many fields of science, ranging from nuclear and particle physics; plasma physics, astrophysics, cosmology, and nuclear fusion; physical chemistry, condensed matter, and materials physics; to synthetic nanostructures and nanophotonics. The purpose of this paper is to heuristically explore two related mysteries, one new, the other more than 50 years old. The solutions to these mysteries have implications for a much broader class of potentials, those addressed by Klaus and Simon. In our recent paper we presented numerical calculations using the Phase Method (PM), which is accurate to 60 digits and to screening lengths $\mathcal{D}\le {10}^3$ au and l = 0–20 of the critical binding parameters for these potentials and, for Yukawa and ECSC, l = 0–12 to $\mathcal{D}\le {10}^5$ au, at 30 digits. In doing so, we discovered an anomalous period-40 sawtooth structure in the critical parameters of the ECSC potential that is not observed for the Yukawa potential. In this second paper, we quantitatively explain the origin and periodicity of this newly discovered structure. To do so, we use two complementary approaches: a “neoclassical” (NC) variant of conventional semiclassical phase-space quantization and the PM for very precise fully quantum calculations. The observed period-40 sawtooth structure is quantitatively explained in terms of a novel “tick-tock” mechanism. The periodicity is calculated in terms of the ratio of phase-space integrals for the primary and secondary potential wells. A quartic double-well potential is used as a simple model to further illustrate the tick-tock mechanism. Using the NC method, an approximate expression is derived to predict the locations of tick-tock glitches from higher-order wells; it is confirmed by a PM calculation up to $\mathcal{D}\le {10}^6$ au. The second mystery is a strangely linear dependence of the total number of bound states vs. screening length for both the Yukawa and ECSC potentials. Using the PM, we confirm and extend these empirical relations. We show, using the PM, that an approximate trivariate linear relation between the square root of the critical screening length $\sqrt{D_c}$, state number n, and angular momentum l applies to these potentials. This, plus a geometrical state accumulation argument, solve the second mystery. We show these properties derive from the scaling relation between screening length and coupling constant and, as such, are predicted to be applicable to the whole class of potentials. These results are expected to be of both theoretical interest and experimental relevance when interpreting spectra or calculating thermal properties. The significance of these results, and the applicability of these methods and conclusions to a vast array of related potentials, is briefly discussed. Full article

Large-area MoS₂ nanotube arrays were successfully prepared using a combination of simple and reliable electrochemical deposition and chemical etching techniques, with highly ordered ZnO nanorod arrays used as the template. The thickness of MoS₂ nanotube walls can be effectively controlled by adjusting the deposition time. The characterization results of SEM and TEM showed the successful preparation of MoS₂ nanotube arrays with different wall thicknesses. The composition of the obtained nanotube arrays was verified to be MoS₂ by EDS, XRD, and XPS characterizations. It is worth noting that compared to MoS₂ nanofilms, the as-prepared MoS₂ nanotube arrays exhibit stronger photoelectric response properties; the on/off ratio and photoresponsivity increased by 2.8 times and 3.8 times, respectively, mainly attributed to its significantly increased specific surface area. These research results provide new ideas for the large-area controllable preparation of MoS₂ low-dimensional nanostructures, as well as new material candidates for the development of low-cost and high-performance photodetectors. Full article

Metasurfaces, planar structures made on a subwavelength scale, enable state-of-the-art manipulation of light and have become a promising solution for compact optical devices. However, fabrication of these nanoscale structures relies on demanding processes, limiting their integration into diverse structures, including three-dimensional ones. In this study, we develop a manufacturing and transfer technique that renders the manipulation and deposition of metasurfaces achievable with high freedom by embedding the nanostructure into a flexible polymer matrix. A metasurface consisting of a TiO₂ nanoparticle array fabricated by nanoimprint lithography was encapsulated within a poly(methyl methacrylate) (PMMA) layer through spin-coating. The layer containing the metasurface was then detached from the original SiO₂ substrate using wet-etching, becoming a free-standing soft sheet carrying nanostructures that can be transferred onto various surfaces. After the transfer, the layer thickness was further tuned through reactive ion etching to modulate the optical response. Incident-angle-resolved transmittance exhibited no significant change in optical bands before and after transfer, confirming that the nanostructure, as well as the photonic band, was well preserved. Thickness reduction of the PMMA cladding induced a clear optical resonance shift, demonstrating controllability of the optical response. This approach provides a versatile route for the installation of metasurfaces and expands the design possibilities for nanophotonic devices. Full article

Recent advances in metasurface-based research have enabled significant reductions in the size and weight of optical devices. By employing metallic nanostructures with subwavelength dimensions, color filtering can be achieved through phenomena such as extraordinary optical transmission (EOT), which allows specific bands of visible light to pass through. However, conventional EOT-based color filters often suffer from strong side peaks outside the desired transmission band, degrading color purity and hindering accurate color reproduction. In this study, we propose an ultrathin, polarization-independent color filter based on a nanohole array that utilizes the EOT effect while effectively suppressing unwanted side peaks. To achieve this, we introduce a modified design in which additional metallic triangular edges are placed around a hole in a conventional hole array. This configuration suppresses higher-order diffraction modes and enables selective transmission at RGB wavelengths, thereby improving spectral selectivity and overall color performance. Full article

The development of high-throughput, sensitive and portable strategies for detecting foodborne pathogens is urgently needed in food safety, especially during an outbreak. Herein, an ultrasensitive suspension array was constructed by designing photonic crystal microsphere (PCM)-assisted loop-mediated isothermal amplification (LAMP) for Staphylococcus aureus detection. The PCM-LAMP suspension array integrated the optical signal enhancement capability of the biomimetic microporous three-dimensional PCM surface with the thousand-fold signal amplification of LAMP. The biomimetic PCMs displayed a periodic dielectric nanostructure and enhanced the fluorescence intensity of the LAMP reaction, leading to high sensitivity. The PCM-LAMP suspension array allowed sensitive detection of the target DNA of S. aureus without long-term culture. Under optimal conditions, the limit of detection for S. aureus genomic DNA reached as low as 0.18 fM, and the assay exhibited excellent specificity against other bacteria. Furthermore, trace target DNA in food samples was accurately quantified, demonstrating its potential for practical applications. Therefore, the developed PCM-LAMP suspension array holds great promise for ultrasensitive and rapid detection of foodborne pathogens. Full article

Fibromyalgia (FM) is a complex chronic syndrome marked by widespread musculoskeletal pain, neurocognitive dysfunction (“fibro-fog”), and autonomic disturbances. Clinical management remains challenging due to subjective symptom reporting and the lack of definitive diagnostics. Emerging evidence points to a multifactorial origin involving central sensitization, neuroendocrine imbalance, and systemic immune-inflammatory alterations. A wide array of candidate biomarkers has been reported in FM, encompassing neurotransmitters (serotonin, norepinephrine), excitatory and inhibitory amino acids, metabolic and glycolytic enzymes, stress-related proteins, autoantibodies, oxidative stress markers and pro-inflammatory cytokines. This molecular heterogeneity reflects the systemic and multidimensional nature of FM. However, most of these biomarkers have been primarily investigated in serum or plasma, where analytical validation and reference ranges are more established. In contrast, the exploration of salivary biomarkers—although highly attractive due to its non-invasive, stress-free, and repeatable collection—remains comparatively limited. Saliva contains a reduced concentration range of many systemic markers and is strongly influenced by circadian rhythms, stress, flow rate, and oral health conditions. While promising candidates such as α-amylase, cortisol, calgranulins, and selected metabolic enzymes have shown potential in saliva, many proposed FM-related biomarkers lack full analytical validation, standardized protocols, and clinically defined reference intervals in this matrix. In this context, non-invasive electrochemical biosensors represent a transformative technological approach. Advanced electrode architectures incorporating nucleic acid probes, redox reporters, and nanostructured materials offer high sensitivity in low-volume and low-concentration biofluids such as saliva. The integration of multiplexed biomarker panels into portable platforms could enable real-time, longitudinal monitoring of FM pathophysiology, supporting phenotype stratification, personalized therapeutic adjustment, and objective disease activity tracking. Full article

Superhydrophobic surfaces are typically achieved through the synergistic integration of appropriate nanostructures and low-surface-energy chemical compositions. This study presents a novel and facile method for constructing a superhydrophobic hierarchical structure directly on a pristine selective laser melting (SLM) titanium surface. The intrinsic partially melted Ti particles, which are inherent to the SLM fabrication process, were strategically utilized as a natural microscale template for the in situ growth of TiO₂ nanotubes via electrochemical anodization. Three distinct micro/nano-topographies were successfully fabricated, integrating the spherical microparticles with either conventional TiO₂ nanotube arrays or separated nanotube arrays. The results demonstrate that the resulting superhydrophobic behavior can be effectively regulated by two key factors: the liquid–solid contact mode at the microscale and the strength of capillary action within the nanostructures. Notably, these characteristics can be tailored by controlling the nanotube diameter and intertubular spacing. These findings contribute to a deeper understanding of the role of micro–nano hierarchical structures in engineering superhydrophobic surfaces, thereby opening new avenues for advanced applications. Full article