Abstract: The present disclosure provides a packet processing method including: in response to a first service packet from a client to a server, replacing a source address of the first service packet with an encrypted client segment identifier corresponding to the client; encrypting the source address and a destination address of the first service packet using a public key of the server according to the encrypted server segment identifier, and sending an encrypted first service packet to the server; in response to a second service packet from the server, decrypting a source address and a destination address of the second service packet using a private key of the client, and replacing the destination address of the second service packet with an address of the client. A packet processing method applied to a server end device, a client end device, a server end device, and a computer-readable medium are further provided.

Abstract: The present disclosure provides a magnetic dressing and a preparation method and use thereof, belonging to the technical field of pharmaceutical preparations. The magnetic dressing includes a magnetic layer, a drug-loading layer, and a protective layer that are stacked in sequence, where the magnetic layer includes polyvinyl alcohol, gluten, and iron particles. In the present disclosure, a swallowed magnetic dressing is controlled by an external magnetic field, and the magnetic dressing is moved to a pathological position by changing a direction of the external magnetic field; after the external magnetic field is removed, the magnetic dressing changes from a ring to a sheet, thereby completing attachment of an entire lesion surface to complete treatment by autonomous drug release.

Abstract: A method for preparing the network-pore polyvinylidene fluoride membrane based on polyvinyl alcohol (PVA) gel includes the steps of (1) mix and stir PVA, masking agent and solvent, heat and dissolve the mixture evenly under 105 degree Celsius to obtain a PVA solution; (2) in the PVA solution, add PVDF and pore-forming agent, where the rest shall be added with the solvent until the total mass fraction sum is 1, stir, heat and dissolve the solution evenly to obtain the homogeneous casting solution; (3) the casting solution is filtered, deaerated, phase-separated and solidified as membrane A; (4) removes the PVA gel from membrane A to obtain membrane B; (5) membrane B is washed with water to remove the residual solvent to obtain the PVDF membrane with network-pore structure. The resulting PVDF membrane is an asymmetric membrane with an ultra-thin cortex and an interpenetrating network-pore sub-cortex structure.

Abstract: The present disclosure relates to a membrane comprising a porous polymer body with a plurality of channels extending through the polymer body, a method of producing the same and a water treatment system comprising the membrane.