Well-posedness of a dissipative nonlinear electrohydrodynamic system in modulation spaces

In this paper we prove the local and global well-posedness of a dissipative nonlinear electrohydrodynamic system in modulation spaces under certain conditions of s, q, and σ.     

Exploration of amphoteric and negative refraction imaging of acoustic sources via active metamaterials

The present work describes the design of three flat superlens structures for acoustic source imaging and explores an active acoustic metamaterial (AAM) to realise such a design. The first two lenses are constructed via the coordinate transform method (CTM), and their constituent materials are anisotropic. The third lens consists of a material that has both a negative density and a negative bulk modulus. In these lenses, the quality of the images is “clear” and sharp; thus, the diffraction limit of classical lenses is overcome. Finally, a multi-control strategy is developed to achieve the desired parameters and to eliminate coupling effects in the AAM.     

Interplay between superconductivity and pseudogap state in bilayer cuprate superconductors

The interplay between the superconducting gap and normal-state pseudogap in the bilayer cuprate superconductors is studied based on the kinetic energy driven superconducting mechanism. It is shown that the charge carrier interaction directly from the interlayer coherent hopping in the kinetic energy by exchanging spin excitations does not provide the contribution to the normal-state pseudogap in the particle–hole channel and superconducting gap in the particle–particle channel, while only the charge carrier interaction directly from the intralayer hopping in the kinetic energy by exchanging spin excitations induces the normal-state pseudogap in the particle–hole channel and superconducting gap in the particle–particle channel, and then the two-gap behavior is a universal feature for the single layer and bilayer cuprate superconductors.     

Transition from fractal to non-fractal scalings in growing scale-free networks

Real networks can be classified into two categories: fractal networks and non-fractal networks. Here we introduce a unifying model for the two types of networks. Our model network is governed by a parameter q. We obtain the topological properties of the network including the degree distribution, average path length, diameter, fractal dimensions, and betweenness centrality distribution, which are controlled by parameter q. Interestingly, we show that by adjusting q, the networks undergo a transition from fractal to non-fractal scalings, and exhibit a crossover from ‘large’ to small worlds at the same time. Our research may shed some light on understanding the evolution and relationships of fractal and non-fractal networks.     

Topologies and Laplacian spectra of a deterministic uniform recursive tree

The uniform recursive tree (URT) is one of the most important models and has been successfully applied to many fields. Here we study exactly the topological characteristics and spectral properties of the Laplacian matrix of a deterministic uniform recursive tree, which is a deterministic version of URT. Firstly, from the perspective of complex networks, we determine the main structural characteristics of the deterministic tree. The obtained vigorous results show that the network has an exponential degree distribution, small average path length, power-law distribution of node betweenness, and positive degree-degree correlations. Then we determine the complete Laplacian spectra (eigenvalues) and their corresponding eigenvectors of the considered graph. Interestingly, all the Laplacian eigenvalues are distinct.     

Random Sierpinski network with scale-free small-world and modular structure

In this paper, we define a stochastic Sierpinski gasket, on the basis of which we construct a network called random Sierpinski network (RSN). We investigate analytically or numerically the statistical characteristics of RSN. The obtained results reveal that the properties of RSN is particularly rich, it is simultaneously scale-free, small-world, uncorrelated, modular, and maximal planar. All obtained analytical predictions are successfully contrasted with extensive numerical simulations. Our network representation method could be applied to study the complexity of some real systems in biological and information fields.     

An empirical study of Chinese language networks

Chinese is spoken by the largest number of people in the world, and it is regarded as one of the most important languages. In this paper, we explore the statistical properties of Chinese language networks (CLNs) within the framework of complex network theory. Based on one of the largest Chinese corpora, i.e. People’s Daily Corpus, we construct two networks (CLN1 and CLN2) from two different respects, with Chinese words as nodes. In CLN1, a link between two nodes exists if they appear next to each other in at least one sentence; in CLN2, a link represents that two nodes appear simultaneously in a sentence. We show that both networks exhibit small-world effect, scale-free structure, hierarchical organization and disassortative mixing. These results indicate that in many topological aspects Chinese language shapes complex networks with organizing principles similar to other previously studied language systems, which shows that different languages may have some common characteristics in their evolution processes. We believe that our research may shed some new light into the Chinese language and find some potentially significant implications.     

Constructing Intrapenetrated Hierarchical Zeolites with Highly Complete Framework via Protozeolite Seeding

Creation of intrapenetrated mesopores with open highway from external surface into the interior of zeolite crystals are highly desirable that can significantly improve the molecular transport and active sites accessibility of microporous zeolites to afford enhanced catalytic properties. Here, different from traditional zeolite-seeded methods that generally produced isolated mesopores in zeolites, nanosized amorphous protozeolites with embryo structure of zeolites were used as seeds for the construction of single-crystalline hierarchical ZSM-5 zeolites with intrapenetrated mesopores (mesopore volume of 0.51 cm³ g⁻¹) and highly complete framework. In this strategy, in contrast to the conventional synthesis, only a small amount of organic structure directing agents and a low crystallization temperature were adopted to promise the protozeolites as the dominant growth directing sites to induce crystallization. The protozeolite nanoseeds provided abundant nucleation sites for surrounding precursors to be crystallized, followed by oriented coalescence of crystallites resulting in the formation of intrapenetrated mesopores. The as-prepared hierarchical ZSM-5 zeolites exhibited ultra-long lifetime of 443.9 hours and a high propylene selectivity of 47.92 % at a WHSV of 2 h⁻¹ in the methanol-to-propylene reaction. This work provides a facile protozeolite-seeded strategy for the synthesis of intrapenetrated hierarchical zeolites that are highly effective for catalytic applications.     

Inclusion Complex of Podophyllotoxin with γ‐Cyclodextrin: Preparation,Characterization, Anticancer Activity,Water‐Solubility and Toxicity

An inclusion complex of podophyllotoxin (PPT) with γ‐cyclodextrin (γ‐CD) was prepared. The behavior, characterization, and water solubility of the inclusion complex were carefully investigated via fluorescence spectroscopy, thermogravimetry, differential scanning calorimetry, X‐ray diffraction analysis, and ¹H and 2D nuclear magnetic resonance spectroscopy. Furthermore, antitumor activity to human cancer lines and toxicity in mice were studied. Results showed that the inclusion complex formed in a 1:1 ratio with a considerable apparent stability constant K_s (4245.5 L·mol^?1). Water solubility was considerably improved. In addition, the anticancer activity of the inclusion complex was better than that of cis‐platinum (DDP, positive control). Most importantly, the toxicity of podophyllotoxin inclusion complex reduced and became more safety to mice which will be great valuable to research its applications as a kind of antitumor drug to human in the further.     

Synthesis and Properties of a Novel FRET-Based Ratiometric Fluorescent Sensor for Cu<Superscript>2+</Superscript>

A novel FRET-based probe LS3 was designed and synthesized. As expected, it exhibited high selectivity and sensitivity for detecting Cu²⁺ over other commonly coexistent metal ions. The detection limit was measured to be 0.0423 μM for Cu²⁺, which can meet the selective requirements for practical application. In addition, the newly synthesized compound 3a/b have potential value of further synthesizing more analogous FRET-based probes.