The European Physical Journal B最新文献

In this study, we analyze a generalist predator–prey model that includes a strong Allee effect in the prey population. We investigate the positivity and boundedness of solutions, identify ecologically relevant equilibrium points, and determine their stability conditions. Further, we analyze the transcritical, saddle-node, Hopf, Bogdanov-Takens, generalized-Hopf, and cusp bifurcations. Our numerical investigation shows that the model exhibits multiple stable states under similar parametric conditions, driven by bifurcation scenarios linked to the Allee effect. It also underscores the significant role of additional foods for predators in shaping system dynamics, unveiling scenarios ranging from the extinction of predators to their persistence, and the coexistence of both the species. Furthermore, our study delves into the impact of environmental white noise on predator–prey dynamics, introducing stochastic elements. We explore noise-induced transitions between two stable states within the system. Overall, our study highlights the complex dynamics of predator–prey interactions, emphasizing the role of Allee effect and additional food sources.

In this study, we explore the emergence of spatial patterns in a predator–prey model influenced by habitat loss, incorporating the effects of linear diffusion. By examining the stability of the system through the Jacobian matrix, we derive conditions for the occurrence of both Hopf and Turing bifurcations using analytical and numerical approaches. Numerical simulations yield Hopf bifurcation diagrams, revealing the system’s dynamic responses to varying conditions. Our findings contribute to the understanding of how habitat loss and harvesting affect the spatial dynamics in predator–prey systems, which are described by partial differential equations (PDEs) under flux boundary conditions. We also investigate the impact of habitat loss due to harvesting on spatial patterns, identifying formations such as spots and stripes as a result of changes in harvesting efforts. We analytically derive the conditions for Turing instability, which are confirmed through numerical validation.

This study investigates the physical properties of the novel mixed metal oxide Mg₃ZnO₄, emphasizing its potential in optoelectronic manufacturing. We provide a comprehensive analysis of its structural, optoelectronic, mechanical, and thermodynamic characteristics, focusing on the ternary compound, which crystallizes in a rocksalt phase similar to the mineral Caswellsilverite. Using advanced density functional theory (DFT) and the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method within the WIEN2k package, we predict the material’s properties in detail. Our structural analysis confirms the stability of Mg₃ZnO₄ in the cubic Pm3̅m space group, revealing key crystallographic parameters. The electronic structure calculations indicate a well-defined energy band gap, confirming its semiconducting nature and suitability for optoelectronic applications. Optical properties, including the dielectric function, absorption, and reflection spectra, demonstrate significant light interaction, highlighting the material’s potential for UV photodetectors and photovoltaic solar cells. The investigation of elastic properties provides critical insights into the mechanical strength and durability of Mg₃ZnO₄, further supporting its viability for demanding applications. Additionally, our thermodynamic analysis reveals the material’s behavior under varying environmental conditions, reinforcing its potential in high-performance optoelectronic devices. These findings establish Mg₃ZnO₄ as a promising candidate for advanced thin-film solar cells and pave the way for future experimental and theoretical studies to explore its unique properties for innovative technological applications.

Graphical abstract

Mass and energy rate (ER) data have been collected for a wide variety of dissipative systems from the biological, cultural, and cosmological realms. They range from 6 × 10^–25 kg and 3 × 10^–25 W for a synthetic, molecular engine to 1.5 × 10⁵³ kg and 10⁴⁸ W for the observable universe and, thus, span 78 mass and 73 ER orders of magnitude, respectively. The combination of (i) convergence of smaller systems (parts) to a larger system and (ii) scaling of ER as a function of mass with a power law constant β > 0 for groups of systems, explains why the ER and mass data points fall in a diagonal band in the double logarithmic ER vs. mass master plot. There appears to be an ER vs. mass limit, corresponding to an energy rate density (ERD = ER/mass) of around 10⁵ W/kg, separating stable, dissipative systems from unstable, “explosive” systems (atomic weapons, supernova, etc.) in all realms. This limit is probably the result of a balance between the energy flow through a system, resulting in increased temperature and pressure, and the strength of the system’s structure and boundary. ERD has been proposed as a metric for the development of the complexity of dissipative systems over deep time Chaisson (Cosmic evolution; The rise of complexity in nature. Harvard University Press, Cambridge, 2002), Chaisson (Sci World J 384912, 2014). Thus, the observed ERD threshold of 10⁵ W/kg may correspond to a maximum of complexity. Several ways to further increase complexity while circumventing this ERD limit are proposed.

Graphical abstract

The study of renewable energy sources is currently an urgent problem. Such materials are produced by constructing phase diagrams or by cation–anionic substitution of an existing material. From this point of view, the formation of a solid solution (CdSe)_1–x(As₂S₃)x can be due to anionic substitution, which is capable of creating functional properties. In this regard, differential thermal analysis (DTA), X-ray diffraction (XRD), microstructural analysis (MSA), as well as measurements of microhardness and density were performed on solid solutions (CdSe)_1–x(As₂S₃)_x. The nature of the chemical interaction of CdSe with As₂S₃ was studied and it was established that the introduction of As₂S₃ into the composition of CdSe leads to the formation of solid solutions. Moreover, it has been found that solid solutions are formed up to 3 mol% concentration of As₂S₃. The temperature dependence of the electrical conductivity and thermo-EMF of (CdSe)_1–x(As₂S₃)_x (x = 0.01; 0.02; 0.03) solid solutions has been studied. It has been established that the obtained alloys of the solid solution (CdSe)_1–x(As₂S₃)_x (x = (x = 0.01; 0.02; 0.03) are semiconductors of medium resistance. When introducing high-resistance samples of 1; 2 and 3 mol. % As₂S₃ into the composition of CdSe, the specific resistance of the alloys increases depending on the composition, and the conductivity decreases accordingly. For alloys of solid solutions (CdSe)_1–x(As₂S₃)_x, in the composition of 0.3; 0.6; 0.8 and 1.0 mol % As₂S₃, the spectral distribution of the photocurrent was studied. Samples containing 0.3; 0.6; 0.8 and 1.0 mol% As₂S₃ are photosensitive materials capable of operating in the wavelength range of 0.4–1.1 μm.

Graphical abstract