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The remarkable capability in regulating light polarization or amplitude at the nanoscale makes metasurface a leading candidate in high-resolution image display and optical encryption. Diverse binary or grayscale meta-images were previously shown concealed in a single metasurface, yet they are mostly stored at same encryption level and share an identical decryption key, running the risk of exposing all images once the key is disclosed. Here, we propose a twofold optical display and encryption scheme demonstrating that binary and grayscale meta-images can be concurrently embedded in a nonspatially multiplexed silicon metasurface, and their decryptions demand for drastically different keys. Unlike previous metasurfaces relying on isolated transmission or phase manipulations upon orthogonal linear polarization incidences, this is made possible by exploiting silicon meta-atoms featuring joint transmission amplitude and polarization control at two wavelengths. In detail, the selected two meta-atoms exhibit large polarization-independent transmission difference (∼85 %) at a wavelength of 800 nm, while functioning as the nano-quarter-wave plate at wavelength of 1200 nm. Through elaborate design in simulation, a binary image can be witnessed when the metasurface is merely illuminated by an unpolarized light of wavelength 800 nm or under white light illumination. However, a distinct binary or grayscale image will come into view by inspecting the metasurface with an analyzer and when the incident light is circularly polarized at the wavelength of 1200 nm. Two metasurface samples are fabricated and successfully verified the claims experimentally. The proposed approach is expected to bring new insights to the field of optical display and encryption.

Cholesteric liquid crystal elastomers (CLCEs) possess tunable optical properties and excellent thermal responsiveness, making them ideal for temperature monitoring applications. However, their broad applications are hindered due to the lack of an efficient method to correlate sample color with temperature. In this study, we developed two machine learning models: a Color-based Temperature Value Prediction Model (CTVPM) and a Color Array-based Temperature Mapping Model (CATMM), to predict temperature values and temperature maps, respectively, from images of colored CLCE samples. CLCE samples with thermal-responsive color are synthesized taking advantage of solvent evaporation-induced molecular alignment and dynamic bond-enabled crosslinking. Experimental results demonstrated that temperature values can be accurately predicted based on RGB images using CTVPM, particularly in the temperature range of 50–70 °C, corresponding to the phase transition temperature range of the CLCE samples. Furthermore, temperature distributions can be effectively mapped using CATMM. Applying machine vision to CLCE samples offers an intuitive and cost-effective method for temperature monitoring and mapping. These findings pave the way for combining CLCEs with deep learning algorithms for sensing and safety-related applications. [ABSTRACT FROM AUTHOR]

Transformer oil will inevitably be contaminated by impurity particles in the actual operation process; Carbon particles are the most abundant conductive particles in transformer oil. The adhesion behavior on the internal insulating surface will cause electric field distortion, which will pose a serious threat to the safe and stable operation of oil-immersed power equipment. To this end, this paper builds an experimental platform for simulating the adhesion behavior of carbon particles in transformer oil, studies the adhesion characteristics of carbon particles, and analyzes the influence of electric field, particle size, oil flow velocity, and other factors on the adhesion of carbon particles. The results show that: the DC electric field is the main factor driving the adhesion of carbon particles on the surface of epoxy resin (with the increase in electric field strength, the degree of adhesion of carbon particles firstly rises and then decreases); the smaller the size of the carbon particles, the easier it is to adhere, and the corresponding electric field strength is different for different sizes of carbon particles when the degree of adhesion is the largest; the velocity of the transformer oil will have a significant impact on the adhesion behavior of the carbon particles (with the increase in the flow velocity, the degree of adhesion of carbon particles firstly rises and then decreases). The research conclusion of this article is helpful in guiding the evaluation of insulation performance and the optimization of insulation structure design in the converter transformer valve-side bushing considering the phenomenon of particle adhesion. [ABSTRACT FROM AUTHOR]

This paper introduces a novel fuzzy logic switched model predictive control (MPC) algorithm for articulated steering vehicles, addressing significant path tracking challenges due to varying road conditions and vehicle speeds. Traditional single-model and parameter-based controllers struggle with tracking errors and computational inefficiencies under diverse operational conditions. Therefore, a kinematics-based MPC algorithm is first developed, showing strong real-time performance but encountering accuracy issues on low-adhesion surfaces and at high speeds. Then, a 4-DOF dynamics-based MPC algorithm is designed to enhance tracking accuracy and control stability. The proposed solution is a switched MPC strategy, integrating a fuzzy control system that dynamically switches between kinematics-based and dynamics-based MPC algorithms based on error, solution time, and heading angle indicators. Subsequently, simulation tests are conducted using SIMULINK and ADAMS to verify the performance of the proposed algorithm. The results confirm that this fuzzy-based MPC algorithm can effectively mitigate the drawbacks of single-model approaches, ensuring precise, stable, and efficient path tracking across diverse adhesion road conditions. [ABSTRACT FROM AUTHOR]

Non‐Hermitian metasurfaces with chiral exceptional points (EPs) in their scattering matrices have garnered significant attention due to their potential for optical polarization manipulation and wavefront control. However, existing approaches predominantly operate under normal incidence conditions, limiting their application in the manipulation of chiral EPs in momentum space. Here, the wavelength‐fixed manipulation of the chiral EPs across a wide‐range momentum space using a polyatomic metasurface is realized, which is attributed to the effective modulation of the collective interference of guided‐mode resonances excited by oblique transverse magnetic (TM) and transverse electric (TE) illuminations. Further, both theoretical and experimental analyses are conducted to explore the potential applications of the proposed design in the wavevector‐ and spin‐selective manipulation of reflection intensity and optical encryption. This work provides a straightforward method to realize and manipulate chiral EPs in momentum space at a fixed operational wavelength, paving the way for designing polarization‐selective and wavevector‐selective devices. [ABSTRACT FROM AUTHOR]