Abstract: A composite polyimide separator and a preparation method thereof, and a secondary battery are described. The preparation method of the composite polyimide separator comprises: providing a porous polyamic acid film; subjecting a diamine aqueous solution and an acyl chloride organic solution to an interfacial polymerization reaction on a surface of the porous polyamic acid film to obtain a composite polyamic acid separator; and placing the composite polyamic acid separator in vapor of an imidization reagent for imidization treatment to obtain the composite polyimide separator. In the present application, by controlling the parameters of the interfacial polymerization reaction, a composite polyamic acid separator with a dense surface, a loose bottom, and an adjustable surface pore size can be obtained.

Abstract: An internal deformation analysis experimental device and method for a three-dimensional particle material, including an internal deformation analysis experimental device for a three-dimensional particle material includes: several particles, which are transparent solids; an infiltration liquid, the refractive index of the particles being the same as that of the infiltration liquid; a container, configured to accommodate the particles and the infiltration liquid; a laser device, arranged on an outer side of the container, the infiltration liquid being able to generate fluorescent light when laser emitted by the laser device irradiates the infiltration liquid; a recording apparatus, arranged on the outer side of the container and configured to collect and acquire a sequential image of the particles; and a computing terminal, the recording apparatus sending the acquired sequential image of the particles to the computing terminal, and the computing terminal constructing a three-dimensional particle system through

Abstract: Provided is a fire resistant yarn, the yarn comprises, based on the total weight of yarn, 4-20% by weight of modified polyphenylene sulfide fiber, and 35-90% by weight of modified acrylic fiber, wherein the modified polyphenylene sulfide is a polyphenylene sulfide which is at least partially sulphonylated, sulfoxidated, or a combination thereof. Provided further is a fire resistant fabric, the fabric comprises, based on the total weight of the fabric, 4-20% by weight of modified polyphenylene sulfide fiber, and 35-90% by weight of modified acrylic fiber, wherein the modified polyphenylene sulfide is a polyphenylene sulfide which is at least partially sulphonylated, sulfoxidated, or a combination thereof. Provided further is a garment and a fire resistant workwear comprising the fire resistant fabric according to the present disclosure.

Abstract: An antenna for generating an arbitrarily directed Bessel beam, including a beam-forming plane and a feeding horn, the beam-forming plane is a dual-layer dielectric substrate structure having a beam focusing function, including: a printed circuit bottom layer, a high-frequency dielectric substrate lower layer, a printed circuit middle layer, a high-frequency dielectric substrate upper layer, and, a printed circuit upper layer; the printed circuit bottom layer, the high-frequency dielectric substrate lower layer, the printed circuit middle layer, the high-frequency dielectric substrate upper layer, and the printed circuit upper layer are co-axially stacked from the bottom to the top: the beam-forming plane is entirely divided into periodically arranged beam-forming units by a plurality of meshes, and each beam-forming unit consists of printed circuit upper, middle and lower metal patches of which centers are on the same longitudinal axis, the high-frequency dielectric substrate lower layer and the high-frequenc

Abstract: An antenna for generating an arbitrarily directed Bessel beam, including a beam-forming plane and a feeding horn, the beam-forming plane is a dual-layer dielectric substrate structure having a beam focusing function, including: a printed circuit bottom layer, a high-frequency dielectric substrate lower layer, a printed circuit middle layer, a high-frequency dielectric substrate upper layer, and, a printed circuit upper layer; the printed circuit bottom layer, the high-frequency dielectric substrate lower layer, the printed circuit middle layer, the high-frequency dielectric substrate upper layer, and the printed circuit upper layer are co-axially stacked from the bottom to the top: the beam-forming plane is entirely divided into periodically arranged beam-forming units by a plurality of meshes, and each beam-forming unit consists of printed circuit upper, middle and lower metal patches of which centers are on the same longitudinal axis, the high-frequency dielectric substrate lower layer and the high-frequenc