Picosecond time-resolved laser emission of coumarin 102: Solvent relaxation

The time-resolved laser emission of coumarin 102 was investigated in various aprotic and protic solvents at picosecond resolution by frequency upconversion technique. The spectral shift of the transient emission spectrum is attributed to solvent reorientation and the results are discussed.     

Application of Kirkwood-Buff theory of liquid mixtures to water-butanol system

The various integrals over the pair correlation functions G_AA' G_WW, and G_AW were calculated for the t-butanol(A)-water(W) system (0 to 8 mole % alcohol) at 25°C by utilizing the thermodynamic quantities, the isothermal compressibility, partial molal volumes, and vapour pressure and by the application of an inverse procedure for Kirkwood-Buff theory of solutions as suggested by Ben-Naim. It is observed that as functions of concentration G_AA', G_AW, and G_WW have extrema in the concentration range studied. The results are interpreted on the basis of structural changes of solvent water. The behavior of G_AA in the concentration range of 0 to 4 % of t-butanol indicates that the strength of hydrophobic interactions decreases with concentration as x_A increases from 0 to 0.04.     

Synergetic extraction and spectrophotometric determination of gold(III)

Summary A method is described for the synergetic extraction and subsequent spectrophotometric determination of gold(III). The gold--furil dioxime-pyridine complex extracted into chloroform has a characteristic yellow colour with an absorption maximum at 330 nm. Beer's law is obeyed in the concentration range [Au(III)]45g/ 10 ml organic phase. A scheme to separate gold from interfering elements by extraction with 4-methyl-2-pentanol in benzene has been proposed.

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Zusammenfassung Ein Verfahren zur synergetischen Extraktion und nachfolgenden spektrophotometrischen Bestimmung von Gold(III) wurde beschrieben. Die Komplexverbindung des Goldes mit-Furildioxim und Pyridin ist in chloroformischer Lösung gelb gefärbt. Ihr Absorptionsmaximum liegt bei 330 nm. Bis 45g Au(III)/10 ml organischer Phase wird das Beersche Gesetz befolgt. Die Trennung des Goldes von störenden Elementen durch Extraktion mit 4-Methyl-2-pentanol in Benzol wurde vorgeschlagen.

     

Free carrier absorption in a ferromagnetic semiconductor below Curie temperature

The free carrier absorption (FCA) in a non-degenerate ferromagnetic semiconductor due to electron-two-magnon scattering is calculated below the Curie temperature, assuming a wide conduction band model. It has been found that in EuO FCA due to two-magnon scattering is proportional to λ^2·1 (wavelength of radiation) and it has been noticed that for high conductivity samples, explanation of FCA requires the inclusion of ionized impurity scattering of electrons besides the two-magnon process.     

Studies on the nature of the reactions and species involved in potentiometric titrimetric determination of uranium

The species and reactions involved in the determination of uranium by the Davies and Gray method have been investigated through the behaviour of the various species when present alone or in various combinations in the reaction medium. The studies indicate the formation of Fe(II) and V(III) in the titration system. These two species appear easily prone to oxidation by the titration medium. Probable reasons for the negative bias found when the titration is not completed in the stipulated time period, and for the sharpening of the end-point by the presence of vanadium(IV), are discussed.     

Anomalous behaviour of hyperfine fields at iron in new magnetic systems RuxFey Si and RuFeB

A new class of magnetic system Ru_xFe_ySi, has been identified in which the hyperfine field at Fe, as sensed by⁵⁷Fe Mossbauer effect, is seen to evolve at a characteristic temperature far below the bulk magnetic ordering temperatures.     

Effect of iso-propanol on the radiolysis of aqueous solutions of periodate

The -radiolysis of IO ₄ ^– in aqueous solution and binary solutions containing iso-propanol has been studied as a function of reactant concentration and absorbed dose. The disappearance of periodate ion in the presence of alcohol is found to be higher as compared to that observed in the pure system. The trend in the G-values determined at various combinations of the reactant concentrations suggests the occurrence of a chain reaction in the radiolytic process.     

RuFeSi — A new magnetic system

A ternary system consisting of Ru, Fe and Si is identified in which the hyperfine field at Fe is seen to evolve at a characteristic temperature, T¹, far below the magnetic ordering temperature, T_m. It is speculated that the magnetic ordering at T_m is itinerant and T¹ corresponds to the localization of the majority spin electrons at the Fe atoms.     

On the length equalities for one-dimensional rings

In this article we characterize noetherian local one-dimensional analytically irreducible and residually rational domains (R,m_R) which are non-Gorenstein, the non-negative integer is equal to τ_R-1 and ?(R/(C+xR))=2, where τ_R is the Cohen-Macaulay type of R, C is the conductor of R in the integral closure of R in its quotient field Q(R) and xR is a minimal reduction of m by giving some conditions on the numerical semi-group v(R) of R.