Promoting information spreading by using contact memory

Promoting information spreading is a booming research topic in network science community. However, the exiting studies about promoting information spreading seldom took into account the human memory, which plays an important role in the spreading dynamics. In this paper we propose a non-Markovian information spreading model on complex networks, in which every informed node contacts a neighbor by using the memory of neighbor's accumulated contact numbers in the past. We systematically study the information spreading dynamics on uncorrelated configuration networks and a group of $22$ real-world networks, and find an effective contact strategy of promoting information spreading, i.e., the informed nodes preferentially contact neighbors with small number of accumulated contacts. According to the effective contact strategy, the high degree nodes are more likely to be chosen as the contacted neighbors in the early stage of the spreading, while in the late stage of the dynamics, the nodes with small degrees are preferentially contacted. We also propose a mean-field theory to describe our model, which qualitatively agrees well with the stochastic simulations on both artificial and real-world networks.Comment: 6 pages, 6 figure

Implementing the 3E assessment model of sustainable development to investigate coastal pollution management: using PET recycling (bottle-to-fiber) as a case study

Recently, plastic pollution of the ocean has been garnering increasing attention. The United Nations considers the problem as a major issue, and the UN Environment Programme (UNEP) has launched a global "Clean Ocean" campaign. An estimated 51 trillion plastic particles can be found in our oceans, and the pollution has caused plastics to enter the food chain. This study investigates the life cycle of recycling waste PET (polyethylene terephthalate) bottles in the ocean to the regeneration of recycled raw materials in the process of producing blankets made from such materials. First, the activity data of the relevant literature was collected, and the life cycle assessment software Open LCA was used as the assessment tool. We assume that the functional unit is 1 kg of recycled PET bottles. Secondly, with the ILCD 2011 Midpoint impact assessment method for environmental impact analysis, we identify the impact of pollutants generated during the recycling process on the environment as follows: Photochemical ozone formation 7872256.41218/ kg NMVOC eq; Fresh-water ecotoxicity 240566129.10051/ CTUe; Human toxicity, cancer effects 120.28305/ CTUh; Human toxicity, non-cancer effects 1.53496/ CTUh. Finally, we conduct risk assessment using the 3E (Engineering, Environment and Economic) assessment model, and propose an overall recovery treatment optimization assessment model

New class of 3D topological insulator in double perovskite

We predict a new class of three-dimensional topological insulators (TIs) in which the spin-orbit coupling (SOC) can more effectively generate a large band gap at $\Gamma$ point. The band gap of conventional TI such as Bi$_2$Se$_3$ is mainly limited by two factors, the strength of SOC and, from electronic structure perspective, the band gap when SOC is absent. While the former is an atomic property, we find that the latter can be minimized in a generic rock-salt lattice model in which a stable crossing of bands {\it at} the Fermi level along with band character inversion occurs for a range of parameters in the absence of SOC. Thus, large-gap TI's or TI's comprised of lighter elements can be expected. In fact, we find by performing first-principle calculations that the model applies to a class of double perovskites A$_2$BiXO$_6$ (A = Ca, Sr, Ba; X = Br, I) and the band gap is predicted up to 0.55 eV. Besides, more detailed calculations considering realistic surface structure indicate that the Dirac cones are robust against the presence of dangling bond at the boundary with a specific termination.Comment: submitted; title changed and new references added; see DOI for published versio