Jan Długosz University

About: Jan Długosz University is a education organization based out in Częstochowa, Poland. It is known for research contribution in the topics: Crystal structure & Luminescence. The organization has 749 authors who have published 2311 publications receiving 19395 citations. The organization is also known as: Higher Teacher Education School.

Anti-mackay polyicosahedral clusters in La-Ni-Mg ternary compounds: synthesis and crystal structure of the La(43)Ni(17)Mg(5) new intermetallic phase.

Abstract: The crystal structure of the complex La43Ni17Mg5 ternary phase was solved and refined from X-ray single crystal diffraction data. It is characterized by a very large unit cell and represents a new structure type: La43Ni17Mg5 − orthorhombic, Cmcm, oS260, a = 10.1895(3), b = 17.6044(14), c = 42.170(3) A, Z = 4, wR1 = 0.0598, wR2 = 0.0897, 4157 F2 values, 176 variables. The crystal structures of the La-rich La−Ni−Mg intermetallic phases La4NiMg, La23Ni7Mg4, and La43Ni17Mg5 have been comparatively analyzed. The constitutive fragments of these structures are binary polyicosahedral core−shell clusters of Mg4La22 and Mg5La24 compositions together with binary polytetrahedral clusters of nickel and lanthanum atoms. The structures of the Mg−La clusters are described in detail as a unique feature of the analyzed intermetallic phases; the dodecahedral Voronoi polyhedra are proposed as a useful tool to characterize polyicosahedral clusters. The arrangements of the building units in the studied phases show some regular...

The BMC method for the existential part of RTCTLK and interleaved interpreted systems

Abstract: In the paper, we focus on the formal verification of multi-agent systems - modelled by interleaved interpreted systems - by means of the bounded model checking (BMC) method, where specifications are expressed in the existential fragment of the Real-Time Computation Tree Logic augmented to include standard epistemic operators (RTECTLK). In particular, we define an improved SAT-based BMC for RTECTLK, and present performance evaluation of our newly developed BMC method by means of the well known train controller and generic pipeline systems.

Signatures of nonadiabatic superconductivity in lithium-decorated graphene

Abstract: Recent studies confirmed that the long-searched-for phonon-mediated superconducting phase in graphene may be induced via lithium deposition. However, it is also suggested that lithium-decorated graphene (${\mathrm{LiC}}_{6}$) behaves as a canonical superconductor, despite the moderate electron-phonon coupling constant and low Fermi energy in this material. Herein, this issue is addressed within the isotropic Eliashberg formalism in the adiabatic and nonadiabatic regimes to account for the potentially pivotal effects hitherto not captured. The conducted analysis indicates signatures of the nonadiabatic superconductivity in ${\mathrm{LiC}}_{6}$ and the resulting effects on the selected thermodynamic properties. It is shown that although the critical temperature obtained in the nonadiabatic regime is similar to the earlier estimates ($\ensuremath{\sim}6$ K), its value corresponds to the smaller magnitude of the Coulomb pseudopotential than previously expected. Moreover, the characteristic ratio of the pairing gap and the inverse temperature is found to notably exceed estimates of the BCS theory. In what follows, the obtained results attempt to present coherent interpretation of the superconducting phase in ${\mathrm{LiC}}_{6}$ and vital insight into its fundamental properties. Moreover, they allow us to draw potential directions for future research on low-dimensional superconductivity by reveling that many other graphene-related superconductors may be subject to nonadiabatic effects. This aspect appears to be essential for the design of new two-dimensional hexagonal superconductors aimed at relatively high critical temperature values.

Solutions to the fractional diffusion-wave equation in a wedge

Abstract: The diffusion-wave equation with the Caputo derivative of the order 0 < α ≤ 2 is considered in polar coordinates in a domain 0 ≤ r < ∞, 0 < φ < φ0 under Dirichlet and Neumann boundary conditions. The Laplace integral transform with respect to time, the finite sin- and cos-Fourier transforms with respect to the angular coordinate, and the Hankel transform with respect to the radial coordinate are used. The numerical results are illustrated graphically.

High-throughput first-principles calculations as a powerful guiding tool for materials engineering: Case study of the AB2X4 (A = Be, Mg, Ca, Sr, ba; B = Al, Ga, in; X = O, S) spinel compounds

Abstract: Modern methods of theoretical and experimental materials engineering can be greatly facilitated by reliably established guiding trends that set directions for a smart search for new materials with enhanced performance. Those trends can be derived from a thorough analysis of large arrays of the experimental data, obtained both experimentally and theoretically. In the present paper, the structural, elastic, and electronic properties of 30 spinel compounds AB2X4 (A = Be, Mg, Ca, Sr, Ba; B = Al, Ga, In; X = O, S) were investigated using the CRYSTAL14 program. For the first time the lattice constants, bulk moduli, band gaps and density of states for these 30 spinels were systematically calculated and analyzed. Influence of the cation and anion variation on the above-mentioned properties was highlighted. Several relations between lattice constants, bulk modulus and ionic radii, electronegativities of constituting ions were found. Several linear equations are proposed, which provide a convenient way to predict the lattice constants and bulk moduli of isostructural spinels.