A torus subgroup of the isotropy group of a bounded homogeneous domain

We show that the isotropy group of a bounded homogeneous domain always has a non-trivial torus subgroup, which gives an answer to the problem posed by Hundemer.     

Reversible control of light reflection of a colloidal crystal film fabricated from monodisperse mesoporous silica spheres

In this letter, we report a novel method for controlling the light reflection of a colloidal crystal. Highly monodisperse mesoporous silica spheres have been successfully organized into a hexagonally close-packed colloidal crystal film. Just by introducing water vapor into the fabricated colloidal film, the structural color and reflection spectra were changed dramatically because of water vapor adsorption occurring in the mesoporous channels. This phenomenon can be observed reversibly over five cycles. We are convinced that this is the first report on controlling the light reflection of a colloidal crystal film dynamically by taking advantage of adsorption properties inherent to mesoporous silica spheres.     

Simultaneous multi-element analysis of total As, Se and Sb on titanium dioxide by slurry sampling-graphite furnace atomic absorption spectrometry

A simple and rapid method for simultaneous determination of As, Se and Sb was studied by graphite furnace atomic absorption spectrometry (GFAAS). Titanium dioxide adsorbing As, Se and Sb was separated from sample solution (100 ml) with a membrane filtration (0.45 μm), and then prepared to be slurry (5.0 ml) by adding ultrapure water. The behavior and influence of titanium dioxide on determination of As, Se and Sb were investigated in this experiment. The optimal conditions of a furnace for these elements were chosen as follows: pyrolysis temperature was 150 °C, and atomization temperature was 2300 °C. The optimal conditions of adsorption for As, Se and Sb on titanium dioxide were listed: pH 2.0 in sample solution; 10 min of stirring time; and 20.0 mg titanium dioxide. The difference of the chemical valence of each element had no effect on the recovery of each element at the same optimal conditions. Limits of detection (3σ) for As, Se and Sb were found to be 0.21 μg l⁻¹, 0.15 μg l⁻¹ and 0.15 μg l⁻¹, respectively, with enrichment rate of 20, when 20 μl of slurry was injected into a Zr-coating tube. The proposed method was applied to tap water and river water.     

Synthetic aperture digital holography with cross-correlation of reconstruction images

We propose a new nonoverlapping synthetic aperture digital holography without additional instruments. The relative distance between adjacent subholograms is estimated from the cross-correlation of reconstruction images from each subhologram. From the cross-correlation, the shift amount of the reconstruction object is estimated. Then, the relationship between the position of the subhologram and the reconstruction object from it enables the relative distance between adjacent subholograms to be calculated. The nonoverlapping synthetic aperture experiments with two subholograms are presented in two ways by changing the object. In the experiments, we show that the resolution of the reconstruction object increased twofold, thanks to the nonoverlapping.     

A new high spin isomer in 146Eu

High spin states of ¹⁴⁶Eu were studied by in-beam gamma ray spectroscopic techniques using ¹⁴⁰Ce(¹⁰B,4n)¹⁴⁶Eu and ¹³⁹La(¹³C,6n)¹⁴⁶Eu reactions. The level scheme was established up to 10MeV. A new high spin isomer with 10ns half life was found. Configurations of yrast states were understood by a weak coupling of f_7/2 neutron to those of ¹⁴⁵Eu. Received: 2 November 1999