Preconcentration of noble metals on a polymer support as complexes of organic reagents and their subsequent determination in the solid phase

Conditions of the sorption preconcentration of Pt, Pd, Au, Ag, and Hg as colored complexes of azorhodanines, tyrodine, and sulfonitrophenol M from acidic solutions (pH 0–2) on a polyamide membrane in the flow mode are determined. At a flow rate of 10–20 mL/min, concentrations of determined elements of 10^-9-10^-7 M, and pressure of 10–20 mm Hg, the complexes are nearly quantitatively sorbed on a polyamide membrane disk (d = 1 cm,m = 2.7 mg, andl = 0.1 mm). The influence of the composition of the test solutions on the formation of the analytical signal in the solid phase is studied. Rapid sorption-spectrometric procedures are developed for the determination of Pt, Pd, Au, Ag, and Hg with the detection limit 5–30 ng of the element in the sorbent zone     

Arsenazo III and its analogues-VII Colour reactions of the rare earth elements with a new reagent-carboxynitrazo

A new reagent, Carboxynitrazo, gives a colour reaction with some rare earth elements. For the individual rare earth elements the sensitivities of the reactions are very different. The difference is greatest for the elements of the Ce- and Y-subgroups. For the first subgroup the molar absorptivities are about 16 x 10(4) l.mole(-1) cm(-1), whereas most of the elements of the Y-group do not give any colour reaction. A possible procedure for the determination of lanthanum in the presence of ytterbium is discussed.     

Complexes of metallochromic substances IX

Summary The optimum conditions of the complex formation between quinquevalent niobium and Chlorosulphophenol S were found. The composition as well as the formation and stability constants of the complex formed were determined and the conditions for a highly sensitive and selective niobium determination were demonstrated.

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Zusammenfassung Die optimalen Bedingungen der Komplexbildung zwischen fünfwertigem Niob und Chlorsulphophenol S wurden gefunden. Die Zusammensetzung sowie die Bildungs- und StabilitÄtskonstanten der gebildeten Komplexe wurden bestimmt und die Bedingungen einer hochempfindlichen und selektiven Niobbestimmung festgestellt.

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Part VIII, see⁸.     

Preparation, structural analysis and dielectric properties of Bi x La1−x FeO3 perovskite

Rare earth element substituted bismuth ferrites (BiFeO₃) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi _x La_1−x FeO₃ (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz). All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity as well as ε′ are found to be maximum for the sample x=0.2 at room temperature.     

Determination of diffusion and activity coefficients in the gallium-indium system by the contact-melting method

The concentration profile in the liquid layer and the rate of contact melting are derived. These characteristics are found as functions of the self-diffusion coefficients D_A and D_B of the components and of the activity coefficients in the regular-solution approximation. Comparison of these equations with the experimental concentration profile and with the experimental contact-melting rate allows calculation of D_A, D_B, and the factork in the expression for Inf in the Ga-In system.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 53–57, April, 1971.     

Single crystalline YAG:Ce phosphor for powerful solid-state sources of white light. The influence of production conditions on luminescence properties and lighting characteristics

It is shown that the spectral properties and spatial distribution of LED radiation with a YAG:Ce single crystalline luminescent converter significantly depend on the morphology of the converter surface. The variation of surface roughness enables one to obtain a light source with a wide range of color characteristics. As a result of optimization of converter parameters we demonstrate a possibility of creating a white light LED with correlated color temperature Т_CC ~ 5000–6500 K and color rendering index CRI ≈ 60–70.     

Complexation of vanadium(IV) with organic reagents on the solid phase of fibrous ion exchangers according to diffuse reflectance and EPR data

Diffuse reflectance and EPR spectroscopic data are reported for the formation of vanadium complexes with the organic reagents (ORs) sulfochlorophenol S (SCP) and pyridylazoresorcinol (PAR) on the solid phase of polyacrylonitrile fiber filled with the cation exchanger KU-2 or the anion exchanger AV-17 or A-5. The effects of the order of sorption of the reaction components, sorption conditions, and the V: OR ratio on the complexation process are discussed. The characteristics of the complexes obtained on the solid phase and in solution are compares. Both M : OR = 1 : 1 and M : OR = 2 : 1 SCP complexes can form on the solid phase without involving any croups of the matrix. PAR forma a 1 : 1 complex involving groups of the A-5 matrix.