Comment on "Perturbation theory of scattering for grazing-incidence fast-atom diffraction", by W. Allison, S. Miret-Artés and E. Pollak, , 2022, , 15851.

In this comment we discuss some aspects of , 2022, , 15851, by Allison , an article intensely motivated by our study of grazing incidence fast atom diffraction (GIFAD) for He-KCl(001) [G. A. Bocan, H.

Long Carbon Fibers for Microwave Absorption: Effect of Fiber Length on Absorption Frequency Band.

This work presents lightweight epoxy foams loaded with very low weight percentages (≤0.5 wt.%) of carbon fibers (CFs) with different lengths (3 mm, 6 mm, and 12 mm) as broadband microwave absorbing materials for anechoic chamber application.

Toward an Ultra-Wideband Hybrid Metamaterial Based Microwave Absorber.

In this paper, we propose a novel design of an ultra-wideband hybrid microwave absorber operating in the frequency range between 2 GHz and 18 GHz. This proposed hybrid absorber is composed of two different layers that integrate a multiband metamaterial absorber and a lossy dielectric layer. The metamaterial absorber consists of a periodic pattern that is composed of an arrangement of different scales of coupled resonators and a metallic ground plane, and the dielectric layer is made of epoxy foam composite loaded with low weight percentage (0.