Abstract: The invention discloses a multi-stage shock absorption and seismic resistance system for urban underground comprehensive pipe tunnels. It includes a pipe gallery tunnel and pipeline grooves. Inside the tunnel, a multi-segment active cavity with multiple arc-shaped inner cavity walls forms a pipe shape with the same axis line as the tunnel. Each inner cavity wall has a sealing elastic contact pad, ensuring a tight seal. Adjacent active cavities connect end to end, forming an inner tunnel body that extends with the pipe tunnel. The outer wall of the inner cavity is fixed to the tunnel's inner wall by a fixed frame. The pipeline groove is installed on the inner wall of the inner cavity through a telescopic frame. The inner tunnel body can swing up and down or left and right, absorbing transverse and longitudinal earthquake waves and resisting impact and collapse.

Abstract: The invention discloses a system for enhancing the damping and aseismic capacities of an underground integrated pipe rack. It includes a pipe fixing assembly installed on the inner walls of the underground space on both sides. The assembly comprises multiple lifting frames arranged vertically and a lifting mechanism. The telescopic end of the lifting mechanism is fixedly connected to the lowermost lifting frame. One side of the lifting frame is slidingly connected to the inner wall of the underground space and features a recess for placing the pipe. A pipe holder inside the recess secures the pipe. During vibrations, the lifting frame slides on the inner wall, causing relative movement between adjacent pipe holders. The vibration is absorbed by the telescopic spring, preventing hard contact between the pipe and the vibration source. This reduces vibration and protects the pipe, thereby enhancing the aseismic capacity of the underground pipe rack.

Abstract: The invention discloses an enhanced anti-seismic structure suitable for urban underground comprehensive pipe galleries. Comprising a polygonal frame with an outer frame and an inner frame arranged inside it. Vertex of the inner frame is connected to the bending position inside the outer frame via a support rod. Outer frame has installation grooves for pipe installation, corresponding one-to-one with its sides. The outer frame, located outside the installation groove, can be disassembled to install a limit frame. A limit mechanism for fixing the pipe is installed on the limit frame. The outer frame, positioned outside the installation slot, can be disassembled to install a limit frame. Screwing in a screw drives a lifting block to compress a spring, causing a top block to press against the pipe surface and secure it. The polygonal frame allows for multiple pipes to be installed simultaneously, enhancing overall stability through the support rod connections.

Abstract: A method for underwater acoustic communication includes steps of S1: capturing a synchronization signal using a cross-correlation operation; S2: performing time forward shifting and reversing processing and time backward shifting and reversing processing, respectively, on the synchronization signal to obtain a forward shifted time reversal coefficient and a backward shifted time reversal coefficient; S3: performing a convolution operation of the forward shifted time reversal coefficient and the backward shifted time reversal coefficient, respectively, with a subsequently captured information sequence to obtain a forward shifted time reversal output and a backward shifted time reversal output; S4: processing the forward shifted time reversal output and the backward shifted time reversal output, respectively, with a forward shift equalizer and a backward shift equalizer to obtain two sets of equalizer outputs; and S5: selecting one of the two sets of equalizer outputs with a smaller error for data decoding to o

Abstract: A method for underwater acoustic communication includes steps of S1: capturing a synchronization signal using a replica correlation operation; S2: performing time reversal forward shift processing and time reversal backward shift processing, respectively, on the synchronization signal to obtain a forward shift time reversal coefficient and a backward shift time reversal coefficient; S3: performing a convolution operation of the forward shift time reversal coefficient and the backward shift time reversal coefficient, respectively, with a subsequently captured information sequence to obtain a forward shift time reversal output and a backward shift time reversal output; S4: processing the forward shift time reversal output and the backward shift time reversal output, respectively, with a forward shift equalizer and a backward shift equalizer to obtain two sets of equalizer outputs; and S5: selecting one of the two sets of equalizer outputs with a smaller error for data decoding to obtain a desired signal.