In this letter, we report a flexible, all-dielectric metasurface fabricated via nanosphere lithography (NSL) and demonstrate its potentials in sensing applications. Regularly arrayed Si cylinders with hexagonal lattice fabricated on polyethylene terephthalate (PET) flexible substrate are exploited to detect applied strain and surface dielectric environment by measuring transmission spectra. Further numerical simulations coincide with experimental observations. The transmission peak can be attributed to coupled magnetic Mie resonance between close-packed Si cylinders. Such Mie resonance based sensor with high flexibility offers an alternative approach towards detecting surrounding variations besides traditional plasmon resonance based sensors, and provides more choices for designing photonic devices operating in the optical regime.

A microwave tunable metamaterial utilizing the semiconductor-to-metal transition of vanadium dioxide (VO₂) is proposed, experimentally demonstrated and theoretically scrutinized. Basic concept of the design involves the combination of temperature-dependent hysteresis in VO₂ with resonance induced heating, resulting in a nonlinear response to power input. A lithographically prepared gold split-rings resonator (SRR) array deposited with VO₂ thin film is fabricated. Transmission spectra analysis shows a clear manifestation of nonlinearity, involving power-dependence of resonant frequency as well as transmitted intensity at both elevated and room temperature. Simulation performed with CST Microwave Studio conforms with the findings. The concept may find applications in transmission modulation and frequency tuning devices working under microwave frequency bands.

The mechanical properties, microstructures and precipitation behaviors in AISI (American Iron and Steel Institute) H13 steel tempered at 863 K for 0.5, 2, 4, 10 and 20 h were investigated. The values for H13 tempered for 2–4 h resulted in die steel that reached the desired properties as specified in NADCA (North American Die Casting Association) #207-2016. The cubic Ostwald ripening model was applied to simulate the coarsening of the large carbides, which were mainly M₂₃C₆ and M₃C, as determined from FactSage predictions as well as measurements with transmission electron microscopy (TEM). TEM revealed that the equivalent circle radius (ECR) decreased during 0.5–2 h, because of the nucleation of many new precipitates. According to the Ashby-Orowan modified precipitation strengthening model, this decrease in ECR leads to an increase in the contribution of precipitates to yield strength. Between 2 and 4 h tempering, the ECR of large carbides increases sharply but then increases asymptotically from 4 to 20 h, which obeys the calculated Ostwald ripening rate for cementite and M₂₃C₆ in H13 after 863 K tempering. This observation for the Ostwald ripening of M₂₃C₆ is in agreement with experimental data for other steels in the literature.

This study examines the microstructure, mechanical properties, and precipitation behavior of 1000 MPa grade GEN3 steel when subjected to various quenching processes, with a focus on the quench and partition (Q&P) technique. The Q&P-treated samples achieved 1300 MPa tensile strength and demonstrated superior yield strength, attributed to their refined substructure and their large amounts of precipitates. The quenched samples exhibited the thinnest martensite laths due to the highest martensite volume. Despite the as-annealed samples having the smallest grain size, the Q&P treatment resulted in optimal microstructural refinement results and a high dislocation density, reaching 1.15 × 10¹⁵ m⁻². Analysis of the precipitates revealed the presence of V₈C₇, M₇C₃, M₂C, and Ti(C, N) across various heat treatments. The application of the McCall–Boyd method and the Ashby–Orowan correction model indicated that quench and tempered (Q&T) samples contained the largest volume of fine precipitates, contributing to their high yield strengths. These findings offer valuable insights for optimizing heat treatment processes to develop advanced high-strength steels for industrial applications.