Abstract: The present disclosure provides a method for experimentally determining a critical sand-carrying gas velocity of a shale gas well. The method includes: collecting well structure and production data, calculating parameter ranges of a gas flow velocity and a liquid flow velocity; carrying out a physical simulation experiment of sand carrying in the shale gas well to obtain the sand holding capacity of the wellbore under different experimental conditions, and calculating a sand holding rate; by observing a change curve of the sand holding rate of the wellbore vs. the gas flow velocity, defining a turning point, and sensitively analyzing the influence of other experimental variables on the turning point, to calculate the critical sand-carrying production of the shale gas well under different conditions. Therefore, this calculation method is simple and applicable, and provides a theoretical basis for the optimization design of water drainage and gas production process.

Abstract: An LED filament, comprising a plurality of light-emitting chips, a metal electrical terminal, a fluorescent glue, an insulating substrate and an electrically and magnetically conductive connector. The plurality of light-emitting chips are connected in series, and encapsulated and fixed on a surface of the insulating substrate by the fluorescent glue, one face of the electrically and magnetically conductive connector is fitted on the other surface of the insulating substrate, the metal electrical terminal is electrically connected to a light-emitting chip at one end of the insulating substrate. Also provided is an LED filament light, comprising a plurality of LED filaments and a permanent magnet. The LED filaments are magnetically and movably connected by means of magnetic attraction via the permanent magnet, and are capable of automatic sliding adjustment during thermal expansion and elongation.

Abstract: An LED filament, comprising a plurality of light-emitting chips, a metal electrical terminal, a fluorescent glue, an insulating substrate and an electrically and magnetically conductive connector. The plurality of light-emitting chips are connected in series, and encapsulated and fixed on a surface of the insulating substrate by the fluorescent glue, one face of the electrically and magnetically conductive connector is fitted on the other surface of the insulating substrate, the metal electrical terminal is electrically connected to a light-emitting chip at one end of the insulating substrate. Also provided is an LED filament light, comprising a plurality of LED filaments and a permanent magnet. The LED filaments are magnetically and movably connected by means of magnetic attraction via the permanent magnet, and are capable of automatic sliding adjustment during thermal expansion and elongation.