Sorption–Spectrophotometric and Test Determination of Zinc(II) as the Mixed-Ligand Complex of 1,10-Phenanthroline and Bromophenol Blue

The interaction of Zn(II), Cd(II), and Pb(II) with 1,10-phenanthroline noncovalently immobilized on silica in the presence of Bromophenol Blue was studied. The optimum conditions of the reaction and the composition of mixed-ligand complexes that are formed at the surface were found, and a scheme was proposed for the interaction at the interface. A sorption–spectrophotometric procedure and a test scale were developed for the determination of zinc with detection limits of 0.011 and 0.018 mg/L, respectively. The procedure was used for the determination of labile zinc species in soil.     

Determination of Cu(II) and Zn(II) using silica gel loaded with 1-(2-thiasolylazo)-2-naphthol

The silica gel with 1-(2-thiasolylazo)-2-naphthol adsorbed was obtained. The adsorption of Cu(II) and Zn(II) from an aqueous solution onto loaded silica gel was studied. The capabilities of 1-(2-thiasolylazo)-2-naphthol immobilized for Cu(II) and Zn(II) preconcentration, visual and diffusion reflectance spectroscopic detection was evaluated. The detection limits were 10 and 15 microg.l(-1), respectively. Visual test scales for metal ions determination in the range 0.65-13 microg per sample were worked out. The developed methods were applied to Cu(II) and Zn(II) determination in natural and tap water. The obtained results agreed well with the reported value.     

Hydrodynamic Behavior of Epoxy and Phenol-Formaldehyde Oligomers in Solution during Thermal Precondensation

The concentration dependences of the relative viscosity of epoxy-4,4'-isopropylidenediphenol (Epikot 1009, E-05) and phenol-formaldehyde (DFFr) resins in Cellosolve solutions in the concentration range c = 5-60%, as well as the kinetics of thermal precondensation of a mixture of E-05 and DPFr resins in solution at molar ratios N ₁/N ₂ = 0.6-1.5, were studied by the method of capillary viscometry. The cluster structure of the surface of coatings on the metal sheet formed by cross-linked epoxy-phenol polymer in various kinetic stages of precondensation of the mixture of E-05 and DFFr resins in solution was studied by electron microscopy with gold decoration. The optimal concentrations of resins in solution and the precondensation kinetics of oligomer mixtures essential for formulating the compounds were calculated.     

Reactivity of nanoparticles; interaction between zinc and copper oxide nanoparticles and iron ions in an alkaline medium

The reactivity of zinc and copper oxide nanoparticles was investigated upon their interaction with iron oxides. It was ascertained that, depending on the reaction conditions, nanoparticles of zinc and copper ferrites (ZnFe₂O₄ and CuFe₂O₄) or core/shell nanoparticles (Fe₃O₄/ZnO) are produced. Size, composition, and structure of the resulting nanoparticles were determined by transmission electron microscopy and X-ray diffraction analysis. The average size of zinc and copper ferrite nanoparticles was ascertained to be 9–10 and 2–3 nm, respectively. For core/shell Fe₃O₄/ZnO nanoparticles, the average size is 20 nm. It was experimentally proved that the photoluminescence radiative characteristics of ZnO nanoparticles are retained in core/shell Fe₃O₄/ZnO nanoparticles.     

Effect of electron irradiation on fluorides of alkali-earth elements (CaF2, SrF2 and BaF2)

The effect of electron irradiation on fluorides of alkaline-earth elements CaF₂, SrF₂, and BaF₂ in the column of an electron transmission microscope is studied by means of elemental and diffraction analysis. It is established that when the current density of the electron beam exceeds the threshold value, we observe the desorption of fluorine and the binding of liberated metal ions by the oxygen of the residual vacuum to form oxide phase MeO (Me = Ca, Sr, and Ba) with the structure of rock salt NaCl.     

Simulation study on light vector meson decays to electron-positron pairs with the ALICE experiment

Simulation study on ω, ϕ, ρ decays to e ⁻ e ⁺ pairs in the ALICE detector for Pb-Pb collisions at LHC energy was performed. The possibility of selecting resonance signals over the combinatorial backgrounds is demonstrated using the realistic simulation tracking and particle identification algorithms of the ALICE offline framework (AliRoot). Results for J/ψ are presented also for comparison.     

Effect of energy losses on the amplitude-frequency characteristic of the electrodynamic system of optical modulators

The results of calculations of main parameters of a slot-type electrodynamic system taking into account losses in a single-mode nonresonance regime of excitation and in the regime of responance excitation in the vicinity of the cutoff frequency are presented. Analytic expressions obtained for the transmission coefficient, resonance frequency, and transmission band can be used in designing wide-band optical modulators. Experimental verification of laboratory prototypes of electrodynamic systems and their application in available modulators confirms the possibility of employment of such analysis for choosing optimal designs of ultrahigh-frequency modulators of optical radiation.