No abstract

No abstract

Social media analytics has drawn new quantitative insights of human activity patterns. Many applications of social media analytics, from pandemic prediction to earthquake response, require an in-depth understanding of how these patterns change when human encounter unfamiliar conditions. In this paper, we select two earthquakes in China as the social context in Sina-Weibo (or Weibo for short), the largest Chinese microblog site. After proposing a formalized Weibo information flow model to represent the information spread on Weibo, we study the information spread from three main perspectives: individual characteristics, the types of social relationships between interactive participants, and the topology of real interaction networks. The quantitative analyses draw the following conclusions. First, the shadow of Dunbar's number is evident in the "declared friends/followers" distributions, and the number of each participant's friends/followers who also participated in the earthquake information dissemination show the typical powerlaw distribution, indicating a rich-gets-richer phenomenon. Second, an individual's number of followers is the most critical factor in user influence. Strangers are very important forces for disseminating real-time news after an earthquake. Third, two types of real interaction networks share the scale-free and small-world property, but with a looser organizational structure. In addition, correlations between different influence groups indicate that when compared with other online social media, the discussion on Weibo is mainly dominated and influenced by verified users.

No abstract

Two novel vanadium(III) complexes: V(dipic)(Hbdc)(H2O)2 (1) and [V2(dipic)2(H2btec)(H2O)4]·2H2O (2) (H2dipic = 2,6-pyridinedicarboxylic acid, H2bdc = 1,3-benzene-dicarboxylic acid, H4btec = 1,2,4,5-benzenetetracarboxylic acid) are synthesized by the reaction of V2(SO4)3, 2,6-pyridinedicarboxylic acid and 1,3-benzene-dicarboxylic acid (for 1) or 1,2,4,5-benzenetetracarboxylic acid (for 2) under hydrothermal condition at 120 °C for 3 days. They were characterized by elemental analysis, IR, UV-Vis, single crystal X-ray diffraction analysis and thermogravimetric analyses (TG). Structural analyses show that the vanadium atoms in the complexes 1 and 2 are both in a pentagonal-bipyramidal coordination environment with the NO6 donor set, and there is intermolecular hydrogen bonding in each complex. Research results found that the complexes exhibited bromination catalytic activity in the single-pot reaction of the conversion of phenol red to bromophenol blue in the mixed solution of H2O-DMF at the constant temperature of 30 ± 0.5 °C with pH = 5.8, and catalytic C-H bond cleavage activity for the peroxidative oxidation (with hydrogen peroxide) of cyclohexane to cyclohexanol and cyclohexanone (the maximum total turnover number is 395) under the mild conditions.

No abstract

The original minimal exposure path problem in wireless sensor networks did not consider path constraint conditions. To consider the actual demand, this article proposes a minimal exposure path problem that requires the passage of the path through the boundary of a certain region. In this situation, because a corresponding weighted graph model cannot be developed, the methods that are used to solve the original minimal exposure path problem (the grid method and the Voronoi diagram method) are ineffective. Thus, this article first converts the problem into an optimization problem with constraint conditions. Because of the difficulty in finding a solution due to the model's high nonlinearity and high dimensional complexity, as well as the special characteristics of the problem, a hybrid genetic algorithm is proposed to find the solutions. This article also provides a proof for the convergence of the designed algorithm. A series of simulation experiments demonstrates that the designed optimization model with constraints and the hybrid genetic algorithm can effectively solve the proposed minimal exposure path problem.

A new hydroxylated and carbonylated melamine was purposefully designed and constructed for the synthesis of targeted porous O-doped g-C3N4 nanosheets.