Abstract: An electromagnetic ultrasonic double wave transducer, comprising a shell (1), and a permanent magnet assembly, a coil (4), a shielding layer (5), and a wire (6) which are provided in the shell (1). The permanent magnet assembly comprises a first permanent magnet (2) and a second permanent magnet (3) sleeved on the first permanent magnet (2). The magnetizing directions of the first permanent magnet (2) and the second permanent magnet (3) are perpendicular to the bottom of the shell (1), and the magnetic field directions of the first permanent magnet (2) and the second permanent magnet (3) are opposite. A non-conducting non-magnetic bushing material (9) is provided between the first permanent magnet (2) and the second permanent magnet (3), and upper end faces of the first permanent magnet (2) and the second permanent magnet (3) realize magnetic circuit closing by means of a magnetic circuit closing element (8).

Abstract: The present invention discloses a performance prediction method and system of pervious concrete based on a meso-structure reconstruction model.

Abstract: An elevating mechanism is provided in the embodiments of the disclosure, which relates to the technical field of a substrate carrying mechanism device and is capable of decreasing incidence of an electrostatic-breakdown phenomenon of a substrate to be processed during an ascending-descending process thereof. The elevating mechanism is configured to carry the substrate to be processed, including a plurality of struts, each of which is provided at a supporting end thereof with a support portion which is in contact with the substrate to be processed, by means of a supporting surface provided on the support portion when the elevating mechanism carries the substrate to be processed; and an ionic wind supply.

Abstract: An elevating mechanism is provided in the embodiments of the disclosure, which relates to the technical field of a substrate carrying mechanism device and is capable of decreasing incidence of an electrostatic-breakdown phenomenon of a substrate to be processed during an ascending-descending process thereof. The elevating mechanism is configured to carry the substrate to be processed, including a plurality of struts, each of which is provided at a supporting end thereof with a support portion which is in contact with the substrate to be processed, by means of a supporting surface provided on the support portion when the elevating mechanism carries the substrate to be processed; and an ionic wind supply.