No abstract

No abstract

The effect of different organic-water mixtures on the acidity constants of alizarine red s (9,10-dihydro-3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid) were determined at 25°C and an ionic strength of 0.1 M by a multiwavelength spectrophotometric method. Two pK a values for the -OH derivatives were determined. The organic solvents used were the amphiprotic (methanol, ethanol), dipolar aprotic (dimethyl sulfoxide), and low basic aprotic (acetonitrile). To evaluate the pH absorbance data, a resolution method based on the combination of soft-and hard-modeling is applied. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data using an established factor analysis model. The data analysis program DATAN was applied for determination of acidity constants. Generally, the pK a values increase with an increase in the content of the organic solvent. This behavior can be accounted for in terms of the high stabilization of both the nonprotonated and the ionic forms of this compound by dispersion forces rather than by hydrogen bonding. There are linear relationships between acidity constants and the mole fraction of different solvents in the mixtures. The effect of solvent properties on acid-base behavior is discussed.

In this study, Ge1-x-ySnxSiy layers (0.01{less than or equal to}x{less than or equal to} 0.06 and 0{less than or equal to}y{less than or equal to}0.12) using Ge2H6, SnCl4 (SnD4) and Si2H6 have successfully grown at 290-310 {degree sign}C on Ge virtual layer on Si(100) by using RPCVD technique. It has been demonstrated that the quality of epitaxial layers is dependent on the growth parameters, layer thickness and the quality of Ge virtual layer. The incorporation of P and B in GeSn matrix has been studied and the effect of dopant specie and concentration on Sn content has been presented. It was found that a proper balance of P, B or Si and Sn flux during the epitaxy improves the incorporation of Sn in Ge matrix. This is explained by the compensation of tensile strain induced by dopants or Si with the compressive strain caused by Sn to obtain the minimum energy in Ge matrix. P-i-n type doped structures of Ge-Sn-Si were grown and the layer quality was analyzed.