Identification of aliphatic 2- and 3-hydroxy acids in the form of cyclic phenylboronates by GLC-mass spectrometry

A method is prepared for identifying aliphatic 2- and 3-hydroxy acids which is based on the GLC-mass spectrometry of the corresponding phenylboronates. The phenyl-boronates are sufficiently volatile for analysis with the aid of GLC and give simple and informative mass spectra.     

Investigating <Superscript>64</Superscript>Zn<Superscript>+</Superscript> ion-doped silicon under conditions of hot implantation

The results from visualizing the structure and identifying the composition of surface and the nearsurface layers of CZ n-Si (100) implanted by ⁶⁴Zn⁺ ions with dose of 5 × 10¹⁶ cm^–2 and energy of 50 keV under conditions of a substrate heated to 350°C are presented. It is found that there is no Si amorphization after Zn implantation, and only one layer 200 nm thick forms and is damaged because of radiation-induced defects. Zn nanoparticles 10–100 nm in size are found on a sample’s surface and in its near-surface layer. Computer analysis and mapping of the elemental and phase composition of FIB crater walls and the surface show that the main elements (54%) in the sample near-surface layer are Si, O, and Zn. The presence of ZnO phase is recorded to a depth of 20 nm in the sample.     

Determination of pH value of isoelectric solution and identification of passive iron surface phases using immersion method

Using the method of phase modeling, the pH values of solutions corresponding to the uncharged surface of passive iron and ferric oxide γ-Fe₂O₃ (pH₀) are compared. According to the theory of connected places, the charge of metal oxide surface is determined by the adsorption or desorption of hydrogen ions leading to a change in the potential drop at the oxide/solution interface. Preliminarily passivated iron electrode was washed with twice-distilled water and placed into 0.5 M NaNO₃ solution with various pH values; the variation in the potential (ΔE) with time was studied. The pH₀ value for passive electrode under the open-circuit conditions was determined by the dependence of ΔE on the pH value (pH₀ 6.2 ± 0.1). The pH₀ value was close to that for γ-Fe₂O₃ (pH₀ 6.2), which was determined by the method of potentiometrical titration of oxide suspension in the nitrate solution. The introduction of surface-active ions Ba²⁺ and Cl^? changes the charge of passive iron surface: Ba²⁺ ions increase the electrode potential, while Cl^? ions decrease it. Comparing the pH₀ values for passive electrode and metal oxides, one can identify the composition of passive electrode surface.     

On the valency of uranium in aegirine and on behavior of isotopes<Superscript>234</Superscript>U and<Superscript>238</Superscript>U at dissolving the mineral

An attempt has been undertaken to find a correlation between the valency forms of uranium and the isotopic ratio (AR=²³⁴U/²³⁸U) following the incongruent dissolving of the mineral aegirine. The low values of AR (≈0.7) observed for hematite are assumed to be connected with the existence of considerable fraction of U(V) form in the original mineral. The discussion is given on the origin of the values of AR≈1 and on its connection with different stabilities of U(IV) and U(VI).