Tianjin Chengjian University

Optical topological quasiparticles have attracted considerable attention due to their unique topological properties. While much effort has been devoted to their generation, studies on the optical field characteristics and functional applications remain limited. In this work, we verified the chirality of optical Stokes bimeron and demonstrated the separation of chiral particles by means of this optical topological quasiparticle generating with a metasurface. Further results reveal that chirality of bimeron fields can enable selective manipulation and separation of chiral particles with opposite handedness. Furthermore, by introducing phase modulation, we achieve in-plane rotation of the bimeron optical field, thereby enabling dynamic control of the chiral particle trajectories, and it can produce a centrifugal-like effect with chiral-dependence. Our findings can be utilized as a versatile platform for chirality-based sorting, transport, and dynamic particle control.

ABSTRACT Extreme‐cold operations are constrained by synergistic material failures, including embrittlement, arrested ion transport, interfacial icing, diminished damping and catastrophic seal leakage. Current engineering is typically countered using a ‘patchwork’ approach of heavy, costly components that introduce new fragilities. Herein, we designed and synthesized a microphase separated hydrophobic eutectogel that retained good stretchability, high damping and continuous ionic conductance from −100°C to 100°C, enabled by a freezing point of −118.7 °C. The strong temperature dependence of Young's modulus was harnessed in two novel applications: a thermally‐actuated smart‐switch and an O‐ring that eliminated cryogenic leakage. By addressing materials‑system constraints in cryogenic environments within a single monolithic medium, this eutectogel simplified system design and enhanced reliability for industrial operation in frigid extremes.

In this paper, a low-cost manual micro- and nano-displacement adjustment mechanism is proposed, based on the principle of flexible hinge transmission and micro-displacement scaling. The manual micro- and nano-displacement platform consists of a micrometer input platform, a nano-output platform, a differential head, and a strain displacement sensor. Firstly, a micro-displacement reduction mechanism based on a flexible beam triangular mechanism and a compact asymmetric flexible beam guiding mechanism are proposed, and a theoretical model is established for static mechanical characteristics, such as the displacement reduction multiplier, guiding stiffness, maximum stress, etc., and this is analyzed and verified by finite element simulation. The software and hardware system of the strain displacement sensor is designed and developed, and the calibration experiments of the strain displacement sensor are completed. Finally, the micro-displacement reduction times, resolution, stability, repeat positioning accuracy, load capacity and travel of the manual micro-nano-displacement platform were analyzed and experimented. The results show that when the input range of the micrometer input platform is 0-1 mm, the travel of the nano-output platform is about 0-16 μm; when a differential head with a step resolution of 2 μm is used to input 2 μm micro-displacement, the minimum displacement output of the nano-output platform is about 35.4 nm; the theoretical and simulated values of the reduction multiple of the micro-nano-displacement are 57.29 and 56.69, respectively; the calibration experiment is performed by the self-developed strain sensors, and capacitive displacement sensors measured the reduction multiples of 57.74 and 62.67, respectively, with high consistency; the vibration range of the platform after the displacement adjustment is about ±30 nm, and the load of 0-300 g has less influence on the output characteristics of the platform.

This study investigates the effects of an arch rib inclination angle and loading scenario on the elasto-plastic stability of steel basket-handle arches to support bridge design. A parametric finite element analysis was performed on 48 models, with inclination angles ranging from 0° to 15° under three vertical loading conditions: uniformly distributed (V), transversely eccentric (V1), and longitudinally eccentric (V2). A nonlinear analysis was conducted using the arc-length method. The results indicate that the ultimate bearing capacity is highest under loading V, followed by V1 and V2, irrespective of the inclination angle. The initial stiffness increases monotonically with inclination in all cases. Under V, the capacity peaks at a 10° inclination before declining, with a corresponding transition from out-of-plane to in-plane buckling at this critical angle. Under V1, out-of-plane buckling dominates, and the capacity fluctuates slightly before increasing with the inclination. Under V2, in-plane antisymmetric buckling prevails, and the capacity decreases gradually as the inclination increases. Eccentric loading induces severe stress concentration and local buckling at the arch feet, accelerating global failure. It is concluded that an inclination angle up to 10° enhances elasto-plastic stability under symmetric vertical loading, whereas eccentric loading substantially reduces the capacity; therefore, symmetric and simultaneous loading on both arches is recommended during construction.