Abstract: Disclosed are a display apparatus and a method for controlling screen projections from multiple devices to a same screen. The display apparatus includes: a display and at least one processor configured to execute instructions to cause the display apparatus to: establish a connection with a first projection device; receive projection contents; control the display to show a top-level application of a user interface displayed, in a case that the projection content is vertical media resource; determine whether the top-level application supports split screen display; when the top-level application supports split screen display, the top-level application is displayed in a first window and the projection contents are displayed in a second window; when the top-level application does not support split screen display, the top level application after proportional reduction is displayed in either of the two windows, and the projection content are displayed in the other window of the two windows.

Abstract: Disclosed are a SARS-COV-2 antigen polypeptide, a recombinant adeno-associated virus (rAAV) expressing the polypeptide, and a vaccine containing the virus. A sequence of the antigen polypeptide is shown in SEQ NO. 1. and SEQ ID NO. 2. A method for preparing the recombinant adeno-associated virus comprises co-incubating pHelper, pRep2Cap5, and an expression vector, transfecting a cell in the presence of polyethyleneimine as a transfection reagent; culturing the cell, then collecting the cell by centrifugation, performing lysis and purification to obtain a purified liquid comprising the recombinant adeno-associated virus. The rAAV is delivered and expressed in vivo to produce a fusion antigen polypeptide, induces the production of serum neutralizing antibodies, which have a neutralizing titer to the novel SARS-COV-2 coronavirus and are expressed continuously; the rAAV composition can be used to immunize humans against the novel coronavirus pneumonia COVID-19.