Abstract: There is provided a solid-state switch device connected between a single-phase power supply source and a load, including: a phase bridge arm circuit, including a first and a second power semiconductor switches, which each includes a first, a second and a control ends and each includes a body diode, wherein the second ends of the first and the second power semiconductor switches are connected in series in phase of a single-phase power supply source; a phase voltage sampling circuit, configured to acquire sampled values of phase voltage of the phase bridge arm circuit; and a control circuit, configured to determine direction of the phase voltage according to the sampled values, turn on one of the power semiconductor switches whose body diode direction is the same as the direction of the phase voltage, and turn on the other within a half cycle after the immediate zero-crossing of the phase voltage.

Abstract: Disclosed in the present invention are a laser chip and a preparation method therefor.

Abstract: A method for cemented material dam construction based on whole-process quality control includes: determining a water-binder ratio of a sand and gravel material through a simulation test; laying rockfill on the first cemented sand and gravel layer before the final setting time of the first cemented sand and gravel layer; adjusting the maximum particle size of the rockfill and the distance between the particles in the rockfill according to the design requirements; spraying a cement slurry on the rockfill to wrap all the particles in the rockfill and laying a second cemented sand and gravel layer before the initial setting time of the cement slurry; performing rolling compaction on the construction layer until the decline in the thickness of the construction layer and the apparent density of the rolled surface meet the design requirements; and completing the cemented material dam construction.