A model of active acid-base surface sites for zinc sulfide electroluminescent phosphors

The Improvement of Foam Concrete Geoecoprotective Properties in Transport Construction

“…This screen must be more reliable if saturate one side of the screen with silica sol and create a protective film preventing leakage through the screen into the soil during exploitation. These geoecoprotective properties are examined in papers [12][13][14][15][16][17][18][19][20].…”

Effect of Electron-Beam Induced Nanostructuring on Surface Properties and Radioluminescence of ZnS:Cu,Br Phosphors

“…For all the samples, a drastic increase of the "green" RL component is observed at wurtzite:sphalerite ratio about 30-40, suggesting that EB-induced phase change promote not only the redistribution of activating agents (Cu and Br) between the bulk and surface of the phosphor but also leads to the spectral bands redistribution causing the brightness growth. To analyze the EB-induced changes in the surface chemistry of the phosphors, the irradiated samples were characterized by the adsorption of acid-base indicators in comparison with similar studies for these samples before EB treatment reported earlier in [19]. The obtained distributions of adsorption centers according to pKa values are shown in Fig.…”

“…A common trend for all the studied phosphors involves the increase in the content of centers with pKa -4.4 and growth in the content of centers with pKa 14.2 with the increase of Cu concentration. According to the model proposed in our previous studies [19], Lewis basic centers with pKa < 0 correspond to two-electron orbitals of surface sulfur atoms S •• , and their amount characterizes the content of surface zinc vacancies VZn'. The Broensted basic centers with pKa > 10 relate to sulfur vacancies VS • or Zn-OH groups on the phosphor surface.…”

Quality Improvement of Concrete Articles

“…Parameter С reflects absorption of silica sol and formation of new phases in the pore space of articles according to the reaction (1). From the data of table 1 it is clear that value of parameter C increases with the rise of density of concrete article [15][16][17][18]. Table 1.…”