Abstract: The present disclosure discloses a preparation method of an aluminum nitride (AlN) composite structure based on a two-dimensional (2D) crystal transition layer. The preparation method of the present disclosure includes: transferring the 2D crystal transition layer on a first periodic groove of an epitaxial substrate; forming a second periodic groove staggered with the first periodic groove on the 2D crystal transition layer; depositing a supporting protective layer; depositing a functional layer of a required AlN-based material; and removing the 2D crystal transition layer through thermal oxidation to obtain a semi-suspended AlN composite structure. The preparation method of the present disclosure has low difficulty and is suitable for large-scale industrial production.

Abstract: An electronic cigarette atomizer and an electronic cigarette are disclosed. The electronic cigarette atomizer comprises an air inlet (1), an air inlet passage (2), an atomization cavity (3), an air outlet passage (4), an air outlet (5), and a suction nozzle (6) that are communicated in sequence. The electronic cigarette atomizer further comprises a housing (8) and an adjustment mechanism (7) for adjusting the air input of the air inlet (1). The air inlet passage (2), the atomization cavity (3), and the air outlet passage (4) are all arranged in the housing (8), and a top of the housing (8) is provided with a top cover (9). The adjustment mechanism (7) comprises a movable member (10) located in the top cover (9) and movable axially along the top cover (9).

Abstract: An electronic cigarette atomization core and atomizer is disclosed. The electronic cigarette atomization core includes an atomization member (3), an outer sleeve (24), a connection sleeve (22), and atomization cotton (14). A lower segment of the connection sleeve (22) is sleeved outside an upper segment of the outer sleeve (24). The outer sleeve (24) is sleeved outside the atomization cotton (14). The outer sleeve (24) is provided with a first e-liquid passage hole (2401) capable of communicating an inner cavity of an electronic cigarette e-liquid bin (12) with the atomization cotton (14). The connection sleeve (22) is axially movable or circumferentially rotatable relative to the outer sleeve (24) to close or open the first e-liquid passage hole (2401). A buffer sealing structure is arranged between the connection sleeve (22) and the outer sleeve (24).

Abstract: A railway freight car bogie includes a side frame, a bolster and a friction damper. The friction damper includes a wedge, a constant friction damping spring, a variable friction damping spring and an ejector rod. The variable friction damping spring in the middle and below the wedge is deviated at a distance in a direction away from a center of the bolster with respect to damping springs at two sides of the variable friction damping spring. An axis of each of the constant friction damping spring and the ejector rod is coincident with an axis of the variable friction damping spring in the middle and below the wedge. The bogie not only has an ideal relative friction coefficient in both an unloaded condition and a loaded condition, a large diamond resistant rigidity, a better vertical dynamics performance and a better transverse dynamics performance.

Abstract: A railway freight car bogie includes a side frame, a bolster and a friction damper. The friction damper includes a wedge, a constant friction damping spring, a variable friction damping spring and an ejector rod. The variable friction damping spring in the middle and below the wedge is deviated at a distance in a direction away from a center of the bolster with respect to damping springs at two sides of the variable friction damping spring. An axis of each of the constant friction damping spring and the ejector rod is coincident with an axis of the variable friction damping spring in the middle and below the wedge. The bogie not only has an ideal relative friction coefficient in both an unloaded condition and a loaded condition, a large diamond resistant rigidity, a better vertical dynamics performance and a better transverse dynamics performance.

Abstract: A central suspension device, a wagon bogie and an express railway wagon, wherein the central suspension device is arranged between a frame and a bolster of the wagon bogie and comprises a rubber-metal pad spring group composed of at least two rubber-metal pad springs, a bottom end of each rubber-metal pad spring is connected with the frame, a top end of at least one rubber-metal pad spring of the rubber-metal pad spring group is connected with the bolster, and a gap exists between the top end of at least one rubber-metal pad spring and the bolster. The central suspension device has multiple stages of rigidities in the transverse and vertical directions, so that the different rigidities can be mutually shifted conveniently on the empty vehicle condition and the heavy-load condition of the vehicle, therefore, the central suspension device is applicable to express railway vehicles for safe and stable running.

Abstract: A central suspension device, a wagon bogie and an express railway wagon, wherein the central suspension device is arranged between a frame and a bolster of the wagon bogie and comprises a rubber-metal pad spring group composed of at least two rubber-metal pad springs, a bottom end of each rubber-metal pad spring is connected with the frame, a top end of at least one rubber-metal pad spring of the rubber-metal pad spring group is connected with the bolster, and a gap exists between the top end of at least one rubber-metal pad spring and the bolster. The central suspension device has multiple stages of rigidities in the transverse and vertical directions, so that the different rigidities can be mutually shifted conveniently on the empty vehicle condition and the heavy-load condition of the vehicle, therefore, the central suspension device is applicable to express railway vehicles for safe and stable running.