Abstract: A three-dimensional (3D) printing-based 3D re-entrant negative Poisson's ratio prefabricated composite protective structure is provided, which includes multiple 3D double-branch re-entrant hexagonal unit cells, steel screws, and a lightweight foam material. Each of the multiple 3D double-branch re-entrant hexagonal unit cells is formed by rotating one of two double-branch re-entrant hexagonal units 90 degrees along a long axis direction thereof and then arranging the double-branch re-entrant hexagonal units orthogonally.

Abstract: A hydrogel includes a polysaccharide including aldehyde groups and carboxy groups, a functionalized chitosan, and iron (III) ions. The hydrogel further includes particles including a core including a carboxy-functionalized polythiophene and a shell including polydopamine. A wound dressing includes the hydrogel and a base layer selected from the group consisting of a gauze, lint, plaster, bandage and cotton wool. The hydrogel is attached or adhered to the base layer.

Abstract: A hydrogel includes a polysaccharide including aldehyde groups and carboxy groups, a functionalized chitosan, and iron (III) ions. The hydrogel further includes particles including a core including a carboxy-functionalized polythiophene and a shell including polydopamine. A wound dressing includes the hydrogel and a base layer selected from the group consisting of a gauze, lint, plaster, bandage and cotton wool. The hydrogel is attached or adhered to the base layer.

Abstract: A method for real-time and in-situ monitoring of freeze-thaw damage to concrete, comprising embedding pairs of gradient electrical resistance probes into a surface of concrete being monitored at a depth of 0-50 mm, the paired gradient electrical resistance probes having an anti-corrosion metal bar, with the buried depth gradient of different pairs of electrical resistance probes being in the range of 1 mm to 20 mm, and the buried depth gradient of the pair of electrical resistance probes nearest to the surface being less than 5 mm; transmitting an impedance value of the concrete measured by the paired gradient electrical resistance probes to a monitoring center for processing; and evaluating a spalling status of freeze-thaw damage to the concrete based on changes in impedance value which may be abrupt. Real-time in-situ monitoring of the freeze-thaw damage of concrete can be achieved by the electrical resistance probes and monitoring center of this invention.

Abstract: Method for real-time and online monitoring the freeze-thaw damage of concrete, firstly, embed pairs of gradient electrical resistance probes into surface of the monitoring concrete at the depth of 0˜50 mm, the paired gradient electrical resistance probes adopt anti-corrosion metal bar, and the buried depth gradient of different pairs of electrical resistance probes in the range of 1 mm to 20 mm, and the buried depth gradient of the pair of electrical resistance probes nearest to the surface is less than 5 mm. Transmit the impedance value of the concrete measured by the paired gradient electrical resistance probes to the monitor center for processing. Judge the spalling status of freeze-thaw damage of concrete though the abrupt change in impedance value. Real-time online monitoring of the freeze-thaw damage of concrete can be achieved by the electrical resistance probes and monitoring center of this invention.