Abstract: A porous graphene, a graphene quantum dot and a green preparation method for the porous graphene and the graphene quantum dot. The method includes adding a starting material, graphite, into an acetic acid aqueous solution of chitosan, using chitosan as a stripping agent, obtaining the porous graphene by an ultrasonic treatment, centrifugation and precipitation, and obtaining the graphene quantum dot by dialyzing a supernatant from the centrifugation. The obtained porous graphene has fewer layers and a larger lateral dimension of sheet. The obtained graphene quantum dot has good dispersity and a uniform particle size distribution. The preparation method is simple to perform and a graphitization degree of the prepared porous graphene and graphene quantum dot is high. The obtained porous graphene can be used as a carrier for a reverse gene transfection, and the graphene quantum dot can be used for cell imaging.

Abstract: A porous graphene, a graphene quantum dot and a green preparation method for the porous graphene and the graphene quantum dot. The method includes adding a starting material, graphite, into an acetic acid aqueous solution of chitosan, using chitosan as a stripping agent, obtaining the porous graphene by an ultrasonic treatment, centrifugation and precipitation, and obtaining the graphene quantum dot by dialyzing a supernatant from the centrifugation. The obtained porous graphene has fewer layers and a larger lateral dimension of sheet. The obtained graphene quantum dot has good dispersity and a uniform particle size distribution. The preparation method is simple to perform and a graphitization degree of the prepared porous graphene and graphene quantum dot is high. The obtained porous graphene can be used as a carrier for a reverse gene transfection, and the graphene quantum dot can be used for cell imaging.

Abstract: The invention presents a method using animation to relax the eyes and help the eyes to do exercises for the ciliary muscles and lens, and enhance the regulating function of the lens. The method does not require any dedicated device except a display screen to play the animation. The method can also interact with the users to provide entertainment.

Abstract: A distributed method for collision-free Beacon-enabled multi-hop IEEE 802.15.4 networking is presented. The method is compatible with the IEEE 802.15.4 standard. It can support a collision-free cluster-tree network for N-to-one data gathering applications or peer-to-peer applications. The beacon schedule and superframe structure arrangement are distributed, which are decided by each device itself based on the GTS allocated by its parent.

Abstract: An un-triangulated hole counting method is described in the invention to evaluate the performance of sensing coverage or wireless communication coverage in a randomly and uniformly deployed sensor network or wireless network without knowing the network topology. This method calculates the expected number of un-triangulated holes, which is the un-triangulated area size in the target area divided by mean un-triangulated hole size, given node density and target area size of the network. The present invention thus provides an aid for controlling the degree of coverage in node deployment for randomly deployed sensor networks. It can also aid to choose a suitable common transmission range for all nodes in a wireless network to provide acceptable wireless radio coverage. A position inside a target area is said to be un-triangulated if it is not enclosed by any triangle formed by connectivity links between three mutually connected nodes.

Abstract: A distributed coverage hole recovery process using connectivity information is proposed for wireless sensor networks and other wireless networks. A link is said to exist between two nodes which are sufficiently close. After a un-triangulated hole is detected enclosing by links between N (N>3) active boundary nodes, the distributed hole recovery process activates one or two redundant nodes to recover the hole at each iteration. This process is performed iteratively by each of the active boundary nodes adjacent to the hole independently without any central controller. It requires 2 hops connectivity or neighbor information from each boundary node adjacent to the hole. After each hole recovery iteration, the hole is reduced in size or split into two smaller holes. Then the hole recovery process repeats until the hole is recovered or detected as unrecoverable.