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Nonlinear nanophotonic devices have shown great potential for on‐chip information processing, quantum source, 3D microfabrication, greatly promoting the developments of integrated optics, quantum science, nanoscience and technologies, etc. To promote the applications of nonlinear nanodevices, improving the nonlinear efficiency, expanding the spectra region of nonlinear response and reducing device thickness are three key issues. Herein, this study focuses on the nonlinear effect of third‐harmonic generation (THG), and present a thin Si meta‐sructure to improve the THG efficiency in the ultraviolet (UV) region. The measured THG efficiency is up to 10−5 at an emission wavelength of 309 nm. Also, the THG nanosystem is only 100 nm in thickness, which is two–five times thinner than previous all‐dielectric nanosystems applied in THG studies. These findings not only present a powerful thin meta‐structure with highly efficient THG emission in UV region, but also provide a constructive avenue for further understanding the light–matter interactions at subwavelength scales, guiding the design and fabricating of advanced photonic devices in future. By utilizing the confined hybrid anapole mode, the ultra‐thin silicon‐based meta‐structure can not only achieve ultraviolet third harmonic generation (THG), but also greatly enhance the conversion efficiency to as high as 10−5, which is a new record to date of the ultraviolet‐region THG in the all‐dielectric nanosystems.

Dimethyl sulfoxide is a suitable solvent for reversible oxygen reduction in the presence of Ca2+, but not sufficiently stable towards the anode. Solvents suitable as anolytes tend to underperform in the context of oxygen reduction. Thus, a combined approach using different electrolytes at the cathode and anode promises superior performance. However, due to the electroosmotic drag, a cross‐contamination of both electrolytes is expected. In this work, the influence of solvent mixtures of dimehtyl sulfoxide as an excellent electrolyte is investigated for the cathode with tetraglymeor tetrahydrofuran for oxygen reduction in the presence of Ca2+ at gold and glassy carbon electrodes using the rotating ring disc electrode assembly and oxygen solubilities and diffusivities are determined. While a high share of tetraglyme and tetrahydrofuran leads to a quick deactivation of the electrodes products, intermediate shares (1:1 mixture by volume), are beneficial for the oxygen reduction. This is due to the increased solubility of oxygen in those solvent. Even more interesting is the fact that the re‐oxidizability of soluble peroxide species is eased by the addition of the ethers. While the reasons for this behavior remain elusive, the beneficial effect of other solvents is an encouraging starting point for a dual electrolyte Ca2+‐battery. The oxygen reduction in tetraglyme and tetrahydrofuran in the presence of Ca2+‐ions leads to solvent degradation and fast blocking of the electrode. Adding dimethyl sulfoxide to the solvent leads to the facile production of superoxide and peroxide, with little deactivation of the electrode.

Fano resonances in plasmonic nanostructures, generated by the spectral interference between a broad resonance or continuum and a narrow resonance, have attracted significant interest in recent literature. Herein, by introducing a nanodisc next to a nanoring via electron beam lithography, a set of Fano resonances for such a ring‐disc‐pair (RDP) hybrid is confirmed through coupling between the dipolar disc mode and different multipolar bonding ring modes. Furthermore, the influence of the RDP's geometric dimensions on the dark‐field scattering spectra is experimentally studied, indicating that the contrast ratio of Fano resonances can be improved by optimizing the ring/disc sizes and narrowing the gap in accordance with previous studies. The disc size can also control the spectral locations of these Fano peaks ranging from the visible to the near‐infrared regime. In addition, by comparing the Fano resonances among a series of ring/split‐ring/rod structures with varying curvatures coupled to a neighboring disc in simulations, it is demonstrated that the RDP presents stronger sensitivity for the same gap distance and shows high‐quality Fano resonances compared with more common disc‐inside‐ring cavities in literature. Fano resonances occurring in coupling ring–nanodisc pairs with varying parameters are systematically studied. By comparing scattering spectra of a series of rings, split‐ring, and rod structures combined with identical discs, it is demonstrated that the pair structure with a disc outside the ring provides relatively stronger Fano resonances due to intense plasmonic near‐field hybridization.

A compact nanosensor that explores the tie-in between stress-induced deformation and optical resonance characteristics is theoretically proposed for pressure sensing. The structure modeling, electromagnetic (EM) wave simulation, and performance evaluations were carried out using the 2D finite element method (FEM). The proposed surface plasmon resonance (SPR) based metal-insulator-metal (MIM) model responds to the pressure induced on the top-facing side of an Ag concave square ring-square disc arrangement (Concave SR-SD) in terms of a structural curve-in into the insulator cavity. These deformations alter the electromagnetic field distributions and plasmonic resonance conditions, shifting the absorption cross-section profiles towards higher wavelengths. The shift in the resonant wavelength (Δλ) for specific measured deformations (d) exhibited by the normal SR-SD hinds at the application level perspective of the designed system in pressure sensing via its optomechanical correlation. Further, multiple parameters like insulator cavity width (W I ) and structure wise modifications in the outer ring structure are investigated for performance optimization, and subline sensitivity values (maximum) of 24.496 nm/MPa and 40.46 nm/MPa are observed from normal and concave SR-SD systems respectively. The suggested nano pressure sensor of suitable sensitivity and broad sensing range promises strong applicability in biomedicine, health monitoring, nanomechanics, chip-based devices, and nanoelectronics.

Analyzing network connectivity is important for evaluating the robustness, efficiency, and overall performance of various architectural designs. By examining the intricate interactions among nodes and their connections, researchers can determine a network’s resilience to failures, its capacity to support efficient information flow, and its adaptability to dynamic conditions. These insights are critical across multiple domains—such as telecommunications, computer science, biology, and social networks—where optimizing connectivity can significantly enhance functionality and reliability. In the literature, there are many variations of connectivity to measure network resilience and fault tolerance. In this survey, we focus on connectivity, tightly super connectivity, and h-extra connectivity within DVcube networks—a compound architecture combining disk-ring and hypercube-like topologies. Additionally, we identify several open problems to encourage further exploration in future research.

In this paper, an ultrathin and dual-band bidirectional metasurface absorber (MSA) based on ring-disk (RD) resonators structure. The simulation results indicate that the proposed MSA can achieve a high absorbance of 95.1% and 93.6% at 6.64 GHz and 13.36 GHz, respectively, for both forward (+  z ) and backward (−  z ) incidences, which is effectively validated by the experiment. The retrieved equivalent electromagnetic (EM) parameters and simulated surface current distributions demonstrate that the dual-band high absorption is mainly attributed to the fundamental dipolar resonance excited by the ring-shape (RP) and disk-shape (DS) resonators, respectively. Moreover, the designed bidirectional MSA can achieve wide-angle absorption for both transverse electric (TE) and transverse magnetic (TM) modes. Furthermore, the absorption performance of the bidirectional MSA can be tuned by varying the geometrical parameters of the unit-cell structure. The proposed dual-band bidirectional MSA has promising application prospects in detection, sensing, and imaging.

The rotating ring‐disk electrode (RRDE) is a common example of generator‐collector assemblies made up of two electron conducting components: the ring (collector) surrounding the centrally located disk (generator). The operating principle of RRDEs is that products of the disk electrode reaction – the rate of which may be influenced by rotation – move to the ring by forced convection, where they participate in an additional electrochemical reaction and will thus be detected. In contrast to classical RRDE experiments, where potentiostatic control is applied to at least one of the electrodes, new techniques were developed in the past decade that utilized dynamic potential control of both electrodes at the same time. The method of “dual dynamic voltammetry” (DDV) has since been applied to study the mechanism of electrochemical processes from electrocatalytic reactions involving dissolved species (such as oxygen reduction) to the study of metal corrosion and polymer degradation phenomena. This paper reviews the basics of the DDV method and some of its possible applications. Tune Both to Find More: Changing simultaneously both the disk and ring potentials of a rotating ring‐disk electrode (RRDE) facilitates better intermediate detection.

Ring Brazilian disc specimens are favored for determining the tensile strength and mixed mode fracture toughness. To further understand the fracture mechanism of ring Brazilian disc specimens, the phase field method is used to investigate the cracking process and peak load of ring Brazilian disc specimens. First, the numerical validity and accuracy of the phase field method is verified by a benchmark example. Then, the effect of aperture ratio and crack inclination angle on the failure process and peak load of ring Brazilian disc specimens is studied. Finally, by combining the phase field method and J -integral method, the influence of prefabricated crack inclination angle and aperture ratios on mode I and II fracture toughness of cracked ring Brazilian disc specimens is discussed.

In the current work, heteroatom-doped graphene materials containing different atomic ratios of nitrogen and sulphur were employed as electrocatalysts for the oxygen reduction reaction (ORR) in acidic and alkaline media. To this end, the hydrothermal route and different chemical reducing agents were employed to synthesize the catalytic materials. The physicochemical characterization of the catalysts was performed by several techniques, such as X-ray diffraction, Raman spectroscopy and elemental analysis; meanwhile, the electrochemical performance of the materials toward the ORR was analyzed by linear sweep voltammetry (LSV), rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) techniques. The main results indicate that the ORR using heteroatom-doped graphene is a direct four-electron pathway, for which the catalytic activity is higher in alkaline than in acidic media. Indeed, a change of the reaction mechanism was observed with the insertion of N into the graphenic network, by the rate determining step changes from the first electrochemical step (formation of adsorbed OOH) on glassy carbon to the removal of adsorbed O (Oad) from the N-graphene surface. Moreover, the addition of sulphur atoms into the N-graphene structure increases the catalytic activity toward the ORR, as the desorption of Oad is accelerated.

Metal‐Organic Frameworks (MOFs) hold great potential to be used as porous (photo)‐electrocatalytic platforms containing large concentration of immobilized molecular catalysts. Indeed, the use of MOFs in a photo‐electrochemical devices was recently demonstrated. However, so far there are no reports of MOFs used for photo‐electrochemical O2 reduction to H2O2. Herein, we utilize a Co‐porphyrin based MOF (Co‐MOF‐525), that produces H2O2 at high faradaic efficiency (95 %), both electrochemically and photo‐electrochemically. Electrochemical characterization show that the active catalytic site is a MOF‐tethered Co(I)‐porphyrin. Additionally, under light illumination, the MOF's intrinsic catalytic rate is significantly accelerated compared to dark electrolysis conditions. Thus, this work could open a path for future implementation of photoactive MOFs in solar fuel schemes. A Co‐porphyrin based MOF (Co‐MOF‐525) is shown to be an effective photo‐electrocatalyst for oxygen reduction into peroxide, performing with a high faradic efficiency of ~95 %.