Maximizing network lifetime is the main goal of designing a wireless sensor network. Clustering and routing can effectively balance network energy consumption and prolong network lifetime. This paper presents a novel cluster-based routing protocol called EECRAIFA. In order to select the optimal cluster heads, Self-Organizing Map neural network is used to perform preliminary clustering on the network nodes, and then the relative reasonable level of the cluster, the cluster head energy, the average distance within the cluster and other factors are introduced into the firefly algorithm (FA) to optimize the network clustering. In addition, the concept of decision domain is introduced into the FA to further disperse cluster heads and form reasonable clusters. In the inter-cluster routing stage, the inter-cluster routing is established by an improved ant colony optimization (ACO). Considering factors such as the angle, distance and energy of the node, the heuristic function is improved to make the selection of the next hop more targeted. In addition, the coefficient of variation in statistics is introduced into the process of updating pheromones, and the path is optimized by combining energy and distance. In order to further improve the network throughput, a polling control mechanism based on busy/idle nodes is introduced during the intra-cluster communication phase. The simulation experiment results prove that under different application scenarios, EECRAIFA can effectively balance the network energy consumption, extend the network lifetime, and improve network throughput.
Five kinds of amino-functionalized (polyaniline, poly(1,2-diaminobenzene), poly(1,3-diaminobenzene), poly(diphenylamine), and poly(o-toluidine)) Fe3O4/SiO2 submicron composites (SCs) were prepared. The SEM and TEM results showed that these SCs possessed a sphere-like core/shell structure with an average diameter of ~500 nm. The XRD results indicated good crystallinity of Fe3O4 core, the amorphous SiO2, and amino-functionalized shells. The XPS results confirmed that amino groups were plentiful rich outside the surface of these SCs which acted as the effective groups for adsorbing the metal ions. These SCs showed a good thermal stability at 20–250 °C. The high saturation magnetization of 60–70 emu/g is better than other similar reports. In3+ adsorption coefficients from aqueous solution by these SCs were higher than 106 mL/g, indicating the higher selectivity and affinity to In3+ compared with Cd2+ and Hg2+ ions. In addition, these SCs could be magnetically reclaimed within 30 s and regenerated with acid after adsorption. The adsorption capabilities only decreased by 6 % after five cycles. The present work indicates that the amino-functionalized Fe3O4/SiO2 SCs are promising for removal of In3+ ions in field application. 相似文献