Abstract: Methods and apparatuses for controlling a reconfigurable intelligent surface (RIS) to generate one or more modulated symbols may be described herein. The processor may be configured to generate an amplitude of the modulated symbol(s) by activating one or more of the plurality of portions of the RIS. The processor may be configured to generate a phase of modulated symbol(s) by controlling one or more phase shifts applied by one or more activated portions of the RIS. The method may include transmitting the one or more modulated symbols using the RIS. The method may include a RIS-based joint beamforming and/or modulation scheme with low PAPR. The RIS may be divided into one or more portions for attaining various gains. The RIS may be divided into an In-phase and/or Quadrature branches. The method may include an Amplitude-phase shift keying (A-PSK) and/or Quadrature amplitude-phase shift keying (AQ-PSK) joint beamforming and/or modulation scheme(s).

Abstract: A drilling casing includes a casing wall and several sand control apparatuses disposed on the casing wall in a spacing. Each sand control apparatus includes a sand control net, a sealing steel sheet and a sealing rubber plug. A plurality of mutually-paralleled sand control meshes are disposed on the sand control net. The sand control mesh exactly faces the sealing steel sheet. The sand control net is connected with the sealing steel sheet through a steel pin. Further, a method of performing fast drilling and completion of a large-borehole multilateral well by the drilling casing includes forming a main borehole by drilling to a destination well depth at one time with a large-size drill bit, drilling a lateral borehole in a natural gas hydrate reservoir by using the drilling casing, and taking out the drill bit for completion. The method is applicable to various natural gas hydrate extraction manners.

Abstract: Disclosed is a new drilling casing, including a casing wall and several sand control apparatuses disposed on the casing wall in a spacing, wherein each sand control apparatus includes a sand control net, a sealing steel sheet and a sealing rubber plug, a plurality of mutually-paralleled sand control meshes are disposed on the sand control net, the sand control mesh exactly faces the sealing steel sheet, and the sand control net is connected with the sealing steel sheet through a steel pin. Further a method of performing fast drilling and completion of a large-borehole multilateral well by using the new drilling casing is disclosed. a main borehole is formed by drilling to a destination well depth at one time with a large size drill bit, a lateral borehole is then drilled in a natural gas hydrate reservoir by using the new drilling casing, and then, the drill bit is taken out for completion. The method is applicable to various natural gas hydrate extraction manners.