University of Lorraine

About: University of Lorraine is a education organization based out in Nancy, France. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 11942 authors who have published 25010 publications receiving 425227 citations. The organization is also known as: Lorraine University.

Dynamic Consideration of DC Microgrids With Constant Power Loads and Active Damping System—A Design Method for Fault-Tolerant Stabilizing System

Abstract: It is known that constant power loads (CPLs) can yield instability in dc-power systems under certain operating conditions. This instability phenomenon is due to the interaction between the dc-grid and the negative input impedance characteristic of the CPLs. Dynamic behavior and stability analysis of a dc-microgrid with CPLs is presented in this paper. Then, a method to design a fault-tolerant stabilizing system for a dc-microgrid with CPLs is presented. It consists in implementing a local stabilizing agent on each CPL. Then, a method to design the stabilizing system is proposed. The method is based on the definition and resolution of a constrained optimization problem. It permits to consider several fault scenarios, such as the electrical reconfiguration of the dc-microgrid, or the failure of an agent. To illustrate the method's effectiveness, it has been implemented and experimentally tested on a test bed.

Bandgap energy bowing parameter of strained and relaxed InGaN layers

Abstract: This paper focuses on the determination of the bandgap energy bowing parameter of strained and relaxed InxGa1−xN layers. Samples are grown by metal organic vapor phase epitaxy on GaN template substrate for indium compositions in the range of 0

Quasi one-dimensional band dispersion and surface metallization in long-range ordered polymeric wires.

Abstract: On-surface covalent self-assembly of organic molecules is a very promising bottom-up approach for producing atomically controlled nanostructures. Due to their highly tuneable properties, these structures may be used as building blocks in electronic carbon-based molecular devices. Following this idea, here we report on the electronic structure of an ordered array of poly(para-phenylene) nanowires produced by surface-catalysed dehalogenative reaction. By scanning tunnelling spectroscopy we follow the quantization of unoccupied molecular states as a function of oligomer length, with Fermi level crossing observed for long chains. Angle-resolved photoelectron spectroscopy reveals a quasi-1D valence band as well as a direct gap of 1.15 eV, as the conduction band is partially filled through adsorption on the surface. Tight-binding modelling and ab initio density functional theory calculations lead to a full description of the band structure, including the gap size and charge transfer mechanisms, highlighting a strong substrate-molecule interaction that drives the system into a metallic behaviour.