scholarly journals Metallic nanoparticles (Cu, Ag, Au) in chalcogenide and oxide glassy matrices: comparative assessment in terms of chemical bonding

2017 ◽  
Vol 20 (1) ◽  
pp. 26-33
Author(s):  
O.I. Shpotyuk ◽  
Author(s):  
M. L. Knotek

Modern surface analysis is based largely upon the use of ionizing radiation to probe the electronic and atomic structure of the surfaces physical and chemical makeup. In many of these studies the ionizing radiation used as the primary probe is found to induce changes in the structure and makeup of the surface, especially when electrons are employed. A number of techniques employ the phenomenon of radiation induced desorption as a means of probing the nature of the surface bond. These include Electron- and Photon-Stimulated Desorption (ESD and PSD) which measure desorbed ionic and neutral species as they leave the surface after the surface has been excited by some incident ionizing particle. There has recently been a great deal of activity in determining the relationship between the nature of chemical bonding and its susceptibility to radiation damage.


2020 ◽  
Vol 92 (2) ◽  
pp. 20101
Author(s):  
Behnam Kheyraddini Mousavi ◽  
Morteza Rezaei Talarposhti ◽  
Farshid Karbassian ◽  
Arash Kheyraddini Mousavi

Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.


2020 ◽  
Vol 29 (12) ◽  
pp. 59-63
Author(s):  
O.I. Parakhina ◽  
◽  
M.N. Lokachuk ◽  
L.I. Kuznetsova ◽  
E.N. Pavlovskaya ◽  
...  

The research was carried out within the framework of the theme of state assignment № 0593–2019–0008 «To develop theoretical foundations for creating composite mixtures for bakery products using physical methods of exposure that ensure homogeneity, stability of mixtures and bioavailability of nutrients, to optimize diets population of Russia». The data on the species belonging of new strains of lactic acid bacteria and yeast isolated from samples of good quality gluten-free starter cultures are presented. A comparative assessment of the antagonistic and acid-forming activity of strains of lactic acid bacteria and the fermentative activity of yeast was carried out. The composition of microbial compositions from selected strains of LAB and yeast was developed. The influence of the starter culture on the new microbial composition on the physicochemical, organoleptic indicators of the bread quality and resistance to mold and ropy-disease was investigated.


2016 ◽  
Vol 39 ◽  
pp. 47-50
Author(s):  
Tiziano Venturini ◽  
Emanuele Trefolini ◽  
Edeardo Patelli ◽  
Matteo Broggi ◽  
Giacomo Tuliani ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document