The linear dispersion law of graphene is modified in periodically gated structures, the charge carriers acquiring a finite effective mass. We show that, in the low energy approximation, periodically gated graphene structures are equivalent, from the point of view of charge transport, to a bilayer-like gated graphene region, i.e., to a material that satisfies the same equation as bilayer graphene but with a potentially different effective mass. The hypothetic bilayer-like material becomes identical to the genuine bilayer graphene if its effective mass matches that of the latter. The effective mass, potential energy, and width of bilayer-like graphene can be identified by imposing the condition that the transmission coefficient through the bilayer-like region, computed using a transfer matrix approach, is identical to that through the periodically gated graphene structure.

In the present work we elaborate the innovative design of the solar air heater and justify it by a Computational Fluid Dynamics (CFD) simulation, implementing and experimentally testing a sample. We propose to use this device for maintenance of constant ambient conditions for thermal comfort and low energy consumption for indoor environments, inside greenhouses, passive houses, and to protect buildings against temperature fluctuations. We tested the functionality of our sample of the solar air heater for 50 weeks and obtained an agreement between the results of the numerical simulation, implemented usingOpenFOAM (an open source numerical CFD software) and the experimental results.

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In this work, we effectuated the numerical simulations of the phase dynamics of an array of Josephson junctions taking into account the capacitive coupling between the neighboring junctions and the diffusion current in the stack. We observed that, if we increase the coupling and the dissipation parameters, the IV characteristic changes qualitatively from the IV characteristics studied before. For currents greater than the critical one, we obtained an additional branch in the IV characteristics. This branch is characterized by a lower voltage than the outermost one. Moreover, we obtained an additional charging of the superconducting layers in the IV region for currents greater than the critical one. We studied the time evolution of this charging by the means of Fast Fourier Transform. We proved that the charge density wave associated with this charging has a complex spectral structure. In addition, we analyzed the behavior of the system for different boundary conditions, appropriate to different experimental setups.