Multifractal Analysis of Dimension Spectrum in Non-uniformly Hyperbolic Systems

Mediterranean Journal of Mathematics - We study the multifractal analysis of dimension spectrum for almost additive potentials in a class of one-dimensional non-uniformly hyperbolic dynamic systems.     

A Note on the Uniqueness of Koebe–Andreev–Thurston Theorem

In this paper, we present a new proof of the uniqueness of Koebe-Andreev-Thurston theorem. Our method is based on the argument principle in complex analysis and reviews the connection between the circle packing theorem and complex analysis.     

A decomposition-related throughput property of tandem queueing networks with blocking

A general throughput property of tandem queueing networks with blocking that relates existing decomposition methods to throughput bounds is discussed using the sample path approach.     

Crystal structure,dielectric and piezoelectric properties of Ta/W codoped Bi3TiNbO9 Aurivillius phase ceramics

Aurivillius phase Bi₃Ti_1−xTa_xNb_1−xW_xO₁₂ high temperature piezoceramics were prepared by a conventional solid state reaction method. The crystal structure, dielectric, electrical conduction and piezoelectric properties were systematically studied. Pure or modified Bi₃TiNbO₉ ceramics revealed the presence of only two-layered Aurivillius phase, indicating that Ta/W doping entered into the B-site of pseudo-perovskite structure and formed solid solutions. The Curie temperature had a strong reliance on the structural distortion. Furthermore, Ta/W dopants act as a donor doping, decrease the number of oxygen vacancies and facilitate the domain wall motion. As a result, Ta/W modifications significantly increase the DC resistivity and piezoelectric properties. Bi₃Ti_0.98Ta_0.02Nb_0.98W_0.02O₁₂ ceramics possess the optimum d₃₃ value (∼12.5 pC/N) together with a high T_C point (∼893 °C). Moreover, the resonance–antiresonance spectra demonstrate that the Ta/W-BTN ceramics are indeed piezoelectric in nature at 600 °C. The d₃₃ value of BTTNW-2 ceramic remains ∼12.2 pC/N after annealing at 700 °C. These factors suggest that the BTTNW-based ceramic is a promising candidate for ultra-high temperature sensor applications.     

Focused ion beam fabrication and magneto-electrical transport properties of La0.67Ca0.33MnO3 nanobridge

La_0.67Ca_0.33MnO₃ particle films with an average particle size of ~150 nm were grown on single-crystal silicon substrate using pulsed electron deposition technique and then focused ion beam was introduced to fabricate nanobridge in size of 300 × 900 nm on the particle film. The magneto-transport properties of both samples were studied. For the film, there is only one resistance peak at 182 K in temperature-dependent resistance (R–T) curves, which is far lower than ferromagnetic–paramagnetic transition temperature (T _C) of 250 K. When compared to the film, double peaks were observed in both R–T curves and magnetoresistance dependent on temperature (MR–T) curves of the nanobridge, one peak is at 186 K, which is very close to metal–insulator transition temperature (T _P) of film, the other one is at 250 K, which is close to the T _C of film, and these two peaks caused separately by grain and grain boundary (GB), which demonstrated that the electrical transport behavior of grain was separated from that of GB.     

The impact of human activity patterns on asymptomatic infectious processes in complex networks

The study of the impact of human activity patterns on network dynamics has attracted a lot of attention in recent years. However, individuals’ knowledge of their own physical states has rarely been incorporated into modeling processes. In real life, for certain infectious processes, infected agents may not have any visible or physical signs and symptoms; therefore, they may believe that they are uninfected even when they have been infected asymptomatically. This infection awareness factor is covered neither in the classical epidemic models such as SIS nor in network propagation studies. In this article, we propose a novel infectious process model that differentiates between the infection awareness states and the physical states of individuals and extend the SIS model to deal with both asymptomatic infection characteristics and human activity patterns. With regards to the latter, we focus particularly on individuals’ testing action, which is to determine whether an individual is infected by an epidemic. The simulation results show that less effort is required in controlling the disease when the transmission probability is either very small or large enough and that Poisson activity patterns are more effective than heavy-tailed patterns in controlling and eliminating asymptomatic infectious diseases due to the long-tail characteristic.     

Theoretical study on the dislocations in the bubble rafts

The core structure of the dislocation in a bubble raft has been evaluated by using the improved P–N equation. The dislocation profile has been obtained explicitly for the bubble radius R=0.296, 0.592, 0.650, 0.888 mm. The results show that the core width of dislocation will increase rapidly when the bubble radius decreases, especially, this trend will become more significant as the radius is more smaller. Our calculated results agree well with the experimental data, and our method can be used to predict the core structure of the dislocation in a bubble raft where bubble-radius is given arbitrarily.     

高功率可变脉宽辐射系统

介绍了一种应用在高功率VHF频段可变脉冲产生及辐射系统的组成。在实验室条件下,通过优化设计、调节实现了数ns至数十ns脉冲宽度辐射输出。利用开路容性天线加载可调电感原理,达到辐射脉冲宽度可变的目的,同时通过并联引入耗能大电感,实现减少辐射脉冲拖尾,增加系统效率的功能;并利用高能量、快脉冲电源为种子电源,为放电回路进行储能放电,利用这一体制减小了系统辐射脉冲间的同步抖动。     

Minimal switching voltage for magnetization reversals in asymmetric nanorings

Micromagnetic simulations based on the Landau–Lifshitz–Gilbert equation are presented to study spin-polarized current induced magnetization switching in asymmetric nanoring-shaped magnetic tunnel junctions. The results show that in a nanoring with an intermediate eccentric distance S, the critical switching voltage V_C reaches the minimum whose magnitude is less than half of the voltage for a symmetric nanoring. In addition to the spin-transfer torque, the current induced Ampère field is found to play a crucial part in the switching process. Analysis is given to explain the existence of such an energy valley that leads to the minimal voltage.     

Generalized quasi-variational-like hemivariational inequalities

In this paper, we introduce and study a new class of generalized quasi-variational-like hemivariational inequalities with multi-valued η$\eta$-pseudomonotone operators in Banach spaces. Some new existence theorems of solutions for this class of generalized quasi-variational-like hemivariational inequalities are proved. The results presented in this paper generalize and extend some known results.