Abstract: A piezoelectric sensor is provided. The piezoelectric sensor comprises a first base, a first conductive layer adjacent to the first base, a second base, a second conductive layer adjacent to the second base; and a first structure between the first conductive layer and the second conductive layer. The first structure comprises a first layer with a first carbon-based material and a plurality of second structures with piezoelectricity. Each of the plurality of second structures comprises a second layer with a second carbon-based material and a third layer adjacent to the second layer. The third layer comprises a material of two-dimensional crystals of unconventional stoichiometries such as Na2Cl crystals.

Abstract: A graphene oxide membrane with a controllable interlayer spacing, a preparation method and use thereof are provided. The preparation method provides of infiltrating a graphene oxide membrane in an aqueous solution A of salt to swell, thereby obtaining the graphene oxide membrane with the controllable interlayer spacing. The aqueous solution A of salt is a solution containing metal cation, and the concentration of the metal cation in the aqueous solution A is from 0.25-2.5 mol/L. The application can precisely control the size of the interlayer spacing of the graphene oxide membrane in the range of 11˜14 ?, and the variable range of this spacing can be controlled to within 0.6˜1 ?. The graphene oxide membrane with the controllable interlayer spacing of the application has excellent mechanical strength, which remains a complete membrane state after 5 hours of infiltration.

Abstract: This invention released a method for gas storage, characterized that gas is stored in the form of nanometer scale bubbles or gas layers on the solid-liquid surfaces. Said gas is hydrogen, the surface of the solid is planar solid surface, irregular solid surface, or porous material surface, especially highly oriented pyrolytic graphite (HOPG) surface, and the liquid is water, inorganic acid, inorganic salt, inorganic alkali, organic solution or colloid solution. The gas to be stored is produced by electrochemical method, inorganic reaction, organic reaction, biologic reaction or physical method.