Abstract: The present disclosure relates to electromagnetic shielding paper based on modification of a conductive MOF material and a preparation method thereof, and belongs to the technical field of electromagnetic shielding. The method includes the following steps: putting polyimide fibers into a precursor solution of the conductive MOF material, and reacting to obtain MOF material modified PI fibers; mixing the modified fibers with aramid pulp, and carrying out papermaking, squeezing and drying to obtain a paper-based precursor; generating a conductive polymer (polypyrrole) in situ by using a gas-phase polymerization method, and finally obtaining the electromagnetic shielding paper based on the modification of the conductive MOF material. The electromagnetic shielding paper prepared by the present disclosure not only has good conductivity and electromagnetic shielding performance, but also has good mechanical properties and thermal stability.

Abstract: A Class-D amplifier includes a loop filter circuit, a comparator circuitry, an output circuitry, and a common-mode control circuitry. The loop filter circuit generates first and second signals according to input and output signals and adjusts common-mode levels of the first and second signals according to a first common-mode signal. The comparator circuitry respectively compares a ramp signal with the first and second signals to generate pulse signals, and a common-mode level of the ramp signal is set based on a second common-mode signal. The output circuitry is powered by a power supply voltage to generate the output signals according to the pulse signals. The common-mode control circuitry performs an AC-coupling operation on the power supply voltage to generate a noise signal and generate one of the first and second common-mode signals according to the noise signal and another one of the first and second common-mode signals.

Abstract: The present disclosure relates to electromagnetic shielding paper based on modification of a conductive MOF material and a preparation method thereof, and belongs to the technical field of electromagnetic shielding. The method includes the following steps: putting polyimide fibers into a precursor solution of the conductive MOF material, and reacting to obtain MOF material modified PI fibers; mixing the modified fibers with aramid pulp, and carrying out papermaking, squeezing and drying to obtain a paper-based precursor; generating a conductive polymer (polypyrrole) in situ by using a gas-phase polymerization method, and finally obtaining the electromagnetic shielding paper based on the modification of the conductive MOF material. The electromagnetic shielding paper prepared by the present disclosure not only has good conductivity and electromagnetic shielding performance, but also has good mechanical properties and thermal stability.

Abstract: Disclosed are a paper-based electromagnetic shielding composite with flame retardant properties and its preparation method and application, belonging to the technical field of electromagnetic shielding. In the present disclosure, PI fibers are modified by polydopamine and grafted with carbon nanotubes, polyimide fiber paper is prepared by a wet papermaking technology, an in-situ synthesis method is used to enable conductive MOFs and polymer PPy to grow on the fiber paper, and finally polyimide resin is sprayed onto the paper to prepare the paper-based electromagnetic shielding composite with flame retardant properties. The method is simple in process without complex synthesis equipment, and solves the problems that polyimide fiber paper is poor in paper forming property and paper mechanical property, and carbon nanotubes are easy to agglomerate in paper and limited in addition amount in the prior art.

Abstract: A folio shielding mechanism suitable for protecting an operation surface of a host is provided. The folio shielding mechanism includes a first shell, a second shell, and a transmission module. The transmission module is disposed on a first supporting surface of the host adjacent to the operation surface, and is connected to the first shell and the second shell. When the first shell is moving towards a first direction, the second shell is driven by the first shell through the transmission module and moving towards a second direction opposite to the first direction, so that the first shell and the second shell would be either joined together above the operation surface for covering the operation surface or apart from each other for exposing the operation surface.