High-performance liquid metal electromagnetic actuator fabricated by femtosecond laser

Small-scale electromagnetic soft actuators are characterized by a fast response and simplecontrol,holding prospects in the field of soft and miniaturized robotics.The use of liquid metal(LM)to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness.Despite research efforts,challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance.To address these challenges,we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method.Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber(1.03 kPa),our actuator exhibits an excellent deformation angle(265.25?)and actuation bending angular velocity(284.66 rad·s^(-1)).Furthermore,multiple actuators have been combined to build an artificial gripper with a wide range of functionalities.Our actuator presents new possibilities for designing small-scaleartificial machines and supports advancements in ultrafast soft and miniaturized robotics.

The genome of okra (Abelmoschus esculentus) provides insights into its genome evolution and high nutrient content

Okra(Abelmoschus esculentus)is an important vegetable crop with high nutritional value.However,the mechanism underlying its high nutrient content remains poorly understood.Here,we present a chromosome-scale genome of okra with a size of 1.19 Gb.Comparative genomics analysis revealed the phylogenetic status of A.esculentus,as well as whole-genome duplication(WGD)events that have occurred widely across the Malvaceae species.We found that okra has experienced three additional WGDs compared with the diploid cotton Gossypium raimondii,resulting in a large chromosome number(2n=130).After three WGDs,okra has undergone extensive genomic deletions and retained substantial numbers of genes related to secondary metabolite biosynthesis and environmental adaptation,resulting in significant differences between okra and G.raimondii in the gene families related to cellulose synthesis.Combining transcriptomic and metabolomic analysis,we revealed the relationship between gene expression and metabolite content change across different okra developmental stages.Furthermore,the sinapic acid/S-lignin biosynthesis-related gene families have experienced remarkable expansion in okra,and the expression of key enzymes involved in the sinapic acid/S-lignin biosynthesis pathway vary greatly across developmental periods,which partially explains the differences in metabolite content across the different stages.Our study gains insights into the comprehensive evolutionary history of Malvaceae species and the genetic basis that underlies the nutrient content changes in okra,which will facilitate the functional study and genetic improvement of okra varieties.

A novel polarization converter based on the band-stop frequency selective surface

A dual-passband single-polarized converter based on the band-stop frequency selective surface(FSS)with a low radar cross-section(RCS)is designed in this article.The unit cell of the proposed converter is formed by a polarization layer attached to the band-stop frequency selective surface.The simulation results reveal that the co-polarization reflection coefficients below-10 d B are achieved in 3.82–13.64 GHz with a 112.4%fractional bandwidth(the ratio of the signal bandwidth to the central frequency).Meanwhile,a polarization conversion band is realized from 8.14 GHz to 9.27 GHz with a polarization conversion ratio which is over 80%.Moreover,the 1 d B transmission window is obtained in two nonadjacent bands of 3.42–7.02 GHz and 10.04–13.91 GHz corresponding to the relative bandwidths of 68.9%and 32.3%,respectively.Furthermore,the radar cross-section of the designed structure can be reduced in the wideband from 2.28 GHz to 14 GHz,and the 10 d B RCS reduction in the range of 4.10–13.35 GHz is achieved.In addition,the equivalent circuit model of this converter is established,and the simulation results of the Advanced Design System(ADS)match well with those of CST Microwave Studio(CST).The archetype of the designed converter is manufactured and measured.The experiment results match the simulation results well,which proves the reliability of the simulation results.