Internal rapid stabilization of a 1-D linear transport equation with a scalar feedback

We use the backstepping method to study the stabilization of a 1-D linear transport equation on the interval (0, L), by controlling the scalar amplitude of a piecewise regular function of the space variable in the source term. We prove that if the system is controllable in a periodic Sobolev space of order greater than 1, then the system can be stabilized exponentially in that space and, for any given decay rate, we give an explicit feedback law that achieves that decay rate

Design of Dispersive Delay Structures (DDSs) Formed by Coupled C-Sections Using Predistortion with Space Mapping

The concept of space mapping is applied, for the first time, to the design of microwave dispersive delay structures (DDSs). DDSs are components providing specified group delay versus frequency responses for real-time radio systems. The DDSs considered in this paper are formed by cascaded coupled C-sections. It is first shown that aggressive space mapping does not provide sufficient accuracy in the synthesis of DDSs. To address this issue, we propose a predistortion space mapping technique. Compared to aggressive space mapping, this technique provides enhanced accuracy, while compared to output space mapping, it provides greater implementation simplicity. Two full-wave and one experimental examples are provided to illustrate the proposed predistortion space mapping technique

Synthesis of NiO nanowalls by thermal treatment of Ni film deposited onto a stainless steel substrate

Two-dimensional nanostructures have a variety of applications due to their large surface areas. In this study, the authors present a simple and convenient method to realize two-dimensional NiO nanowalls by thermal treatment of a Ni thin film deposited by sputtering onto a stainless steel substrate. The substrate surface area is supposed to be significantly increased by creating nanowalls. The effects on the nanowall morphology of the thermal treatment temperature and duration are investigated. A mechanism based on the surface diffusion of Ni2+ ions from the Ni base film is then proposed for the growth of the NiO nanowalls. The as-synthesized NiO nanowalls are characterized by scanning electron microscopy, energy-dispersive x-ray analysis, x-ray diffraction, transmission electron microscopy and high resolution transmission electron microscopy

Enhanced Bandwidth and Diversity in Real-Time Analog Signal Processing (R-ASP) using Nonuniform C-section Phasers

We show that a continuously nonuniform coupled line C-section phaser, as the limiting case of the step discontinuous coupled-line multisection commensurate and non-commensurate phasers, provides enhanced bandwidth and diversity in real-time analog signal processing (R-ASP). The phenomenology of the component is explained in comparison with the step-discontinuous using multiple-reflection theory and a simple synthesis procedure is provided. The bandwidth enhancement results from the suppression of spurious group delay harmonics or quasi-harmonics, while the diversity enhancement results from the greater level of freedom provided by the continuous nature of the nonuniform profile of the phaser. These statements are supported by theoretical and experimental results

Realization of aligned three-dimensional single-crystal chromium nanostructures by thermal evaporation

Aligned three-dimensional single-crystal chromium nanostructures are fabricated onto a silicon substrate by thermal evaporation in a conventional thermal evaporator, where the incident angle of Cr vapor flux with respect to the substrate surface normal is fixed at 88°. The effects of the deposition time and incident angle on the morphology of the resulting nanostructures are investigated. The achieved Cr nanostructures are characterized by scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and surface area measurement. This study provides a convenient way to fabricate three-dimensional single-crystal Cr nanostructures, which is suitable for batch fabrication and mass production. Finally, the same technique is employed to fabricate the nanostructures of other metals such as Ag, Au, Pd, and Ni