Mechanical responses and crystal plasticity model of CoCrNi medium-entropy alloy under ramp wave compression

It is of substantial scientific significance and practical value to reveal and understand the multiscale mechanical properties and intrinsic mechanisms of medium-entropy alloys(MEAs)under high strain rates and pressures.In this study,the mechanical responses and deformation mechanisms of an equiatomic CoCrNi MEA are investigated utilizing magnetically driven ramp wave compression(RWC)with a strain rate of 105 s^(−1).The CoCrNi MEA demonstrates excellent dynamic mechanical responses and yield strength under RWC compared with other advanced materials.Multiscale characterizations reveal that grain refinement and abundant micromechanisms,including dislocation slip,stacking faults,nanotwin network,and Lomer–Cottrell locks,collectively contribute to its excellent performance during RWC.Furthermore,dense deformation twins and shear bands intersect,forming a weave-like microstructure that can disperse deformation and enhance plasticity.On the basis of these observations,we develop a modified crystal plasticity model with coupled dislocation and twinning mechanisms,providing a relatively accurate quantitative description of the multiscale behavior under RWC.The results of simulations indicate that the activation of multilevel microstructures in CoCrNi MEA is primarily attributable to stress inhomogeneities and localized strain during RWC.Our research offers valuable insights into the dynamic mechanical responses of CoCrNi MEA,positioning it as a promising material for use under extreme dynamic conditions.

Editorial for the Special Issue on Deep Matter & Energy

Volatile elements—such as carbon, hydrogen, sulfur, nitrogen, and halogens—are minor constituents of Earth’s deep interior. Despite their low abundances, deep volatiles mediate major Earth processes, including magma generation, volcanism, mantle convection, and plate tectonics, which control the exchange of volatiles between Earth’s deep interior and its surface. Over geological time, deep volatiles play critical, primary roles in governing energy resources, natural hazards, atmospheric composition, climate, and planetary habitability. Human activities after the industrial revolution have played an impactful, secondary role, and the resulting risk of add-on effects that could lead to irreversible runaway catastrophes has greatly increased.

The on-chip thermoelectric cooler:advances,applications and challenges

With the development of 5G technology and increasing chip integration,traditional active cooling methods struggle to meet the growing thermal demands of chips.Thermoelectric coolers(TECs)have garnered great attention due to their rapid response,significant cooling differentials,strong compatibility,high stability and controllable device dimensions.In this review,starting from the fundamental principles of thermoelectric cooling and device design,high-performance thermoelectric cooling materials are summarized,and the progress of advanced on-chip TECs is comprehensively reviewed.Finally,the paper outlines the challenges and opportunities in TEC design,performance and applications,laying great emphasis on the critical role of thermoelectric cooling in addressing the evolving thermal management requirements in the era of emerging chip technologies.

Nanoscale all-optical devices based on surface plasmon polaritons

Surface plasmon polariton,a kind of surface electromagnetic wave propagating along the interface between metals and dielectrics,provides an excellent platform for the realization of integrated photonic devices due to its unique properties of confining light into subwavelength scales.Our recent research progresses of nanoscale integrated photonic devices based on surface plasmon polaritons,including all-optical switches,all-optical logic discriminator,and all-optical routers,are introduced in detail.

On-chip polarization splitter based on a multimode plasmonic waveguide

The miniaturization of polarization beam splitters(PBSs) is vital for ultradense chip-scale photonic integrated circuits. However, the small PBSs based on complex hybrid plasmonic structures exhibit large fabrication difficulties or high insertion losses. Here, by designing a bending multimode plasmonic waveguide, an ultrabroadband on-chip plasmonic PBS with low insertion losses is numerically and experimentally realized. The multimode plasmonic waveguide, consisting of a metal strip with a V-shaped groove on the metal surface, supports the symmetric and antisymmetric surface plasmon polariton(SPP) waveguide modes in nature. Due to the different field confinements of the two SPP waveguide modes, which result in different bending losses, the two incident SPP waveguide modes of orthogonal polarization states are efficiently split in the bending multimode plasmonic waveguide. The numerical simulations show that the operation bandwidth of the proposed PBS is as large as 430 nm because there is no resonance or interference effect in the splitting process. Compared with the complex hybrid plasmonic structure, the simple bending multimode plasmonic waveguide is much easier to fabricate. In the experiment, a broadband(Δλ≈ 120 nm) and low-insertion-loss(<3 dB with a minimum insertion loss of 0.7 dB) PBS is demonstrated by using the strongly confined waveguide modes as the incident sources in the bending multimode plasmonic waveguide.