Percolation on interdependent networks with different group size distributions under targeted attack

Traditional research studies on interdependent networks with groups ignore the relationship between nodes in dependency groups. In real-world networks, nodes in the same group may support each other through cooperation and tend to fail or survive together. In this paper, based on the framework of group percolation, a cascading failure model on interdependent networks with cooperative dependency groups under targeted attacks is proposed, and the effect of group size distributions on the robustness of interdependent networks is investigated. The mutually giant component and phase transition point of networks with different group size distributions are analyzed. The effectiveness of the theory is verified through simulations. Results show that the robustness of interdependent networks with cooperative dependency groups can be enhanced by increasing the heterogeneity between groups under targeted attacks. The theory can well predict the numerical simulation results. This model provides some theoretical guidance for designing robust interdependent systems in real world.

Quantum batteries at the verge of a phase transition

Starting from the observation that the reduced state of a system strongly coupled to a bath is, in general, an athermal state, we introduce and study a cyclic battery-charger quantum device that is in thermal equilibrium, or in a ground state, during the charge storing stage. The cycle has four stages: the equilibrium storage stage is interrupted by disconnecting the battery from the charger, then work is extracted from the battery, and then the battery is reconnected with the charger; finally, the system is brought back to equilibrium. At no point during the cycle are the battery-charger correlations artificially erased. We study the case where the battery and charger together comprise a spin-1/2 Ising chain, and show that the main characteristics - the extracted energy and the thermodynamic efficiency - can be enhanced by operating the cycle close to the quantum phase transition point. When the battery is just a single spin, we find that the output work and efficiency show a scaling behavior at criticality and derive the corresponding critical exponents. Due to always present correlations between the battery and the charger, operations that are equivalent from the perspective of the battery can entail different energetic costs for switching the battery-charger coupling. This happens only when the coupling term does not commute with the battery's bare Hamiltonian, and we use this purely quantum leverage to further optimize the performance of the device.

Dynamical Gibbs–non-Gibbs Transitions in the Curie–Weiss Potts Model in the Regime $$\beta <3$$

We consider the Curie–Weiss Potts model in zero external field under independent symmetric spin-flip dynamics. We investigate dynamical Gibbs–non-Gibbs transitions for a range of initial inverse temperatures $$\beta <3$$ β < 3 , which covers the phase transition point $$\beta = 4\log 2$$ β = 4 log 2 (Ellis and Wang in Stoch Process Appl 35(1):59–79, 1990). We show that finitely many types of trajectories of bad empirical measures appear, depending on the parameter $$\beta $$ β , with a possibility of re-entrance into the Gibbsian regime, of which we provide a full description.

RELAXATION FREQUENCY SHIFT IN TRIGLYCINE SULFATE UNDER THE INFLUENCE OF SILICA NANOPARTICLES AT LOW FREQUENCIES

The present work is devoted to clarifying the influence of silica nanoparticles on dielectric relaxation frequencies of a classical ferroelectric – triglycine sulfate at low frequencies (102 – 107 Hz) from 20 ˚C to phase transition point for composite samples prepared at different composition weight ratios. Theresults indicated the reduction of relaxation frequency with increasing the silica content due to the intensified interaction between nanoparticles and tryglycine sulfate inclusion. The nature of this interaction was thoroughly discussed in this study.

Holographic entanglement entropy in general holographic superconductor models with logarithmic nonlinear electrodynamics

We explore the behaviors of the holographic entanglement entropy (HEE) in holographic superconductor models with logarithmic nonlinear electrodynamics (LNE) both in AdS soliton and in AdS black hole backgrounds. We observe that the slope of the HEE at the phase transition point behaves discontinuously for different LNE parameters b and geometry parameters $$\ell $$ ℓ , which may be a quite general feature for the second order phase transition. Moreover, at the critical point, the stronger nonlinearity of the LNE gives rise to the smaller HEE in metal/superconductor while leaves the HEE in insulator/superconductor model as is. Interestingly, the behavior of the HEE also implies a “confinement/deconfinement” phase transition in the insulator/superconductor model, and the critical width of the phase transition depends on the chemical potential and the strength of the LNE.

Hot Deformation Behavior and Processing Maps of Ti-6554 Alloy for Aviation Key Structural Parts

With the development of the aviation industry, the performance requirements of materials for aviation large-scale structural parts are getting higher and higher. Ti-6554 alloy is the material of choice for aviation large-scale structural parts, but its forming process window is narrow and its microstructure is sensitive to process parameters, which affects the performance of the alloy. By adjusting the existing hot deformation process, it is of great significance to improve the properties of the alloy. Hot compression tests of Ti-6554 alloy were carried out at temperatures of 715–840 °C and strain rates of 0.001–1 s−1. The results show that the flow stress and peak stress increased significantly with the increase of strain rate. At the same strain rate, the strain required for the stress to reach the peak point is smaller with the temperature increases. When the deformation temperature is below the phase transition point, the volume fraction and size of primary α phase gradually decrease with the increase of deformation temperature, while when the temperature is above the phase transition point, with the increase of deformation temperature, β grains grow up gradually, and the grain boundary bending effect is more obvious. The hyperbolic-sine Arrhenius constitutive equation was established. The correlation coefficient between experimental data and model calculated data reached 0.994. It indicates that the stress constitutive model proposed in this study can accurately reflect the stress characteristics of Ti-6554 alloy. Based on the dynamic material model, the processing maps of the alloy were established. The optimum hot deformation parameters range of the alloy was determined by analyzing the processing maps: the deformation temperature range of 800–830 °C, the strain rate range of 0.001–0.01 s−1. Through the analysis of the processing maps, the instability regions in the process of cross-phase forging can be effectively avoided, and the performance of the forging can be effectively improved.