Development of mechanically strong and adhesive hydrogels with self-recovery and self-healing properties is important for many applications but has proven to be very challenging. Here, we reported a double-network design strategy to synthesize a fully physically cross-linked doublenetwork (DN) hydrogel, consisting of the first gelatin network and the second poly(N-hydroxyethyl acrylamide) network where both networks were mainly cross-linked by hydrogen bonds. The resultant gelatin/pHEAA hydrogels exhibited high mechanical property (tensile stress of 1.93 MPa, tensile strain of 8.22, tearing energy of 4584 J/m 2 ), fast self-recovery at room temperature (toughness/stiffness recovery of 70.2%/ 68.0% after 10 min resting), and good self-healing property (self-healed tensile stress/strain of 0.62 MPa/3.2 at 60 °C for 6 h). More importantly, gelatin/pHEAA hydrogels also exhibited strong surface adhesion on different hydrophilic solid surfaces, as indicated by high adhesion energy (i.e., interfacial toughness) of 645 J/m 2 on glass, 867 J/m 2 on Al, 702 J/m 2 on Ti, and 579 J/m 2 on ceramics. Surface adhesion can be largely retained after multiple, repeatable adhere on/peel off actions. Reversible and strong mechanical properties in bulk and on solid surfaces are likely attributed to reversible hydrogen bondings and physical coordinate bonds between the networks and between networks and surfaces. This work demonstrates our design principle that multiple physical bonds in both networks offer excellent mechanical recoverability, self-healing, and self-adhesive properties, while DN structure provides strong and tough mechanical properties via efficient energy dissipation by sacrificed bonds, which offers a new possibility to develop next-generation hydrogels with desirable properties used for soft robotics, wearable electronics, and human−machine interfaces.

This paper presents a detailed review of both theory and algorithms for the Cheeger cut based on the graph 1-Laplacian. In virtue of the cell structure of the feasible set, we propose a cell descend (CD) framework for achieving the Cheeger cut. While plugging the relaxation to guarantee the decrease of the objective value in the feasible set, from which both the inverse power (IP) method and the steepest descent (SD) method can also be recovered, we are able to get two specified CD methods. A compare study of all these methods are conducted on several typical graphs.

The polymerization of the bisaliphatic epoxy resin, 3,4‐epoxycyclohexylmethyl, 3,4‐epoxycyclohexylcarboxylate initiated by diaryliodonium or triarylsulfonium salts under both microwave energy and conventional thermal heating, was investigated. DSC and FTIR methods to determine the extent of polymerization were established. Some polymerization phenomena such as polymerization selectivity, polymerization temperature shift, and polymerization temperature shift by microwave power setting in microwave fields compared to thermal fields were investigated. To explain the phenomena, a theory that a new partition function existed in microwave fields was proposed with statistical thermodynamics. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4230–4246, 2004

The eigenvectors for graph 1-Laplacian possess some sort of localization property: On one hand, any nodal domain of an eigenvector is again an eigenvector with the same eigenvalue; on the other hand, one can pack up an eigenvector for a new graph by several fundamental eigencomponents and modules with the same eigenvalue via few special techniques. The Courant nodal domain theorem for graphs is extended to graph 1-Laplacian for strong nodal domains, but for weak nodal domains it is false. The notion of algebraic multiplicity is introduced in order to provide a more precise estimate of the number of independent eigenvectors. A positive answer is given to a question raised

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