Abstract: A brake disc and a preparation method, a brake system, and a vehicle. The brake disc comprises a dense region and a plurality of nanoporous regions distributed at intervals in the dense region, wherein the dense region comprises a carbon fiber reinforced silicon carbide material, and the nanoporous region comprises pyrolytic carbon in a continuous phase and carbon particles distributed in the pyrolytic carbon, wherein the pore size of the nanoporous region ranges from about 10 nm to about 100 nm, and the porosity ranges from about 15% to about 30.

Abstract: A brake disc, a preparation method for a brake disc, and a vehicle. The brake disc is a carbon-ceramic brake disc and is in the shape of a disc, and the overall graphitization degree of the brake disc ranges from 5% to 25%.

Abstract: An electronic cigarette atomization core, an electronic cigarette atomization assembly, and an electronic cigarette. The electronic cigarette atomization core includes a porous ceramic base body and a heating body, the porous ceramic base body includes a liquid absorbing surface and an atomization surface, the heating body is arranged on the atomization surface, the heating body is a porous heating body, and the porous heating body has a porosity less than or equal to 30%.

Abstract: Embodiments of the present disclosure provide an electronic-cigarette vaporization core and an electronic cigarette. The electronic-cigarette vaporization core includes a porous body and a heating element. The porous body includes an e-liquid absorption end and a vaporization end. The heating element is arranged at the vaporization end of the porous body. The porous body includes a first porous body and a second porous body. A groove is provided on a surface of the first porous body close to the e-liquid absorption end. The second porous body is partially or completely embedded in the groove. A thermal shrinkage difference between the first porous body and the second porous body is less than 2%.