Spectrophotometric determination of iron(II) with 1,10-phenanthroline in the presence of large amounts of iron(III)

A study was made to establish proper conditions for the selective determination of Fe(II) by the 1,10-phenanthroline method in the presence of large amounts of Fe(III). It was shown that fe(III) is effectively masked by fluoride. The pH of the solution to be masked should be below 2.5 in order to prevent acceleration by the fluoride of aerial oxidation of Fe(II).     

Qualitative analysis of ultraviolet-absorbing substances by use of fluorescent materials

Developments of detection techniques of ultraviolet absorbing substances with fluorescent materials are reviewed.     

Impurity nuclear physics

Using a germanium-detector array for hypernuclear γ spectroscopy (Hyperball), we measured B(E2) of the ⁷ _ΛLi hypernucleus and observed a significant shrinkage of the ⁶Li core induced by a Λ-particle. In this way, nuclear properties can be drastically changed by introducing a Λ-particle, which can be investigated by high-resolution hypernuclear γ spectroscopy. In the future neutron-rich hypernuclei will also be studied, where interesting modifications of nuclear structure by a Λ-particle are expected. Received: 1 May 2001 / Accepted: 4 December 2001     

Scattering and diffraction of a plane wave by a randomly rough half-plane

The scattering and diffraction of a TE (transverse electric) plane wave by a randomly rough half-plane are studied by a combination of three techniques: the Wiener-Hopf technique, the small perturbation method and a probabilistic method based on the shift-invariance of a homogeneous random function. By use of the D^a-Fourier transformation based on the shift-invariance, it is shown that the scattered wave is written by an inverse Fourier transformation of a homogeneous random function with a complex parameter. For a small rough case, such a random function with a complex parameter is expanded in a perturbation series and then the first-order solution is obtained exactly in an integral form. The first-order solution involves two physical processes such that the edge-diffracted wave is scattered by the randomly rough plane and the scattered wave, due to roughness, is diffracted by the half-plane. The solution is transformed into a sum of the Fresnel integrals with complex arguments, an integral along the steepest descent path and a branch-cut integral, which are evaluated numerically. Then, intensities of the coherently scattered wave and incoherent wave are calculated in the region near the edge and illustrated in figures.     

A synthesis of 5-amino- and 5-hydroxy-l-ethyl-1,4-dihydrio-4-oxo-3-quinolinecarboxylic acids and their derivatives

The synthesis and antimicrobial activity of 5-Hydroxy-l-ethyl-1,4-dihydrio-4-oxo-3-quinolinecarboxylic acids and their derivatives have been investigated. The 5-hydroxy-3-quinolinecarboxylic acids were prepared by thermal cyclization of 3-oxocyclohexenylaminomethylenemalonates followed by aromatiza-tion with iodine-ethanol, ethylation and hydrolysis of products. The 5-amino derivatives were prepared by several steps involving novel aromatization of isoxazole intermediates.     

Laser fluorimetry of polynuclear aromatic hydrocarbons based on time-resolved fluorescence detection

Three polynuclear aromatic hydrocarbons are quantified from the pre-exponential factor of the fluorescence decay curve, instead of the integrated fluorescence intensity. The slopes of the calibration plots are independent of the oxygen concentration in the solvent as predicted. Deaeration of sample solutions gives lower detection limits (around 10^?10 M); the extent of improvement depends on the fluorescence lifetime.