Temperature dependence of local density augmentation for acetophenone N,N,N',N'-tetramethylbenzidine exciplex in supercritical water

Local density augmentation around exciplex between acetophenone and N,N,N',N'-tetramethylbenzidine in supercritical water was measured by observing the peak shift of transient absorption spectrum at temperatures from 380 to 410 degrees C and at pressures from 6 to 37 MPa. Large local density augmentation was observed at lower solvent densities. Local density augmentation was evaluated by the excess density, which was defined as the difference between local density and bulk density, and the density enhancement factor, which was defined by the ratio of the local density to the bulk density. The number of solvating molecules was estimated with a Langmuir adsorption model. The excess density was found to exhibit a maximum at approximately 0.15 g cm(-3), which decreased with increasing temperature. The density enhancement factor was found to decrease with increasing temperature; however, its value was much greater than unity at 410 degrees C, which provides evidence that exciplex-water interactions still exist at these conditions. The temperature dependence of local density augmentation around the exciplex in supercritical water was comparable with that in supercritical carbon dioxide, which suggests that the ratios of the solute-solvent and solvent-solvent interactions are comparable between these two systems.     

Integral Formulas for the Minimal Representation of O(p,2)

The minimal representation of O(p,q) (p+q: even) is realized on the Hilbert space of square integrable functions on the conical subvariety of R^p+q–2. This model presents a close resemblance of the Schrödinger model of the Segal–Shale–Weil representation of the metaplectic group. We shall give explicit integral formulas for the inversion together with the analytic continuation to a certain semigroup of O(p+2,C) of the minimal representation of O(p,2) by using Bessel functions.Mathematics Subject Classifications (2000) primary 22E30; secondary 22E46, 20M20, 43A80.     

Variable range hopping in Si:P at very low temperature

The resistivity of doped semiconductor Si: P in the intermidiate concentration range was measured in low temperature region down to 10 mK. In the lowest temperatures Mott's formula for the variable range hopping is shown to be not applicable and T^-n-like temperature dependence of resistivity is confirmed. The Importance of the level correlation in the random system is discussed.     

Evidence for a Peierls-Fröhlich state of one-dimensional platinum complex,K1.81Pt(C2O4)2·2H2O

Chemical analyses and electrical conductivity measurements were made on K_xPt(C₂O₄)₂·nH₂O (KDOX). X os 1.62 for α-KDOX and 1.81 for γ-KDOX. 2k_F calculated from the degree of partial oxidation shows that the lattice modulation wave in the superstructure of γ-KDOX is produced by the condensation of 2k_F phonon.     

Lueders' lines detection by means of brittle coatings

The objective of this paper is to compare some of the techniques used to detect Lueders' lines and present the results of a more extensive study using the brittle-coating method. A hot-rolled steel tensile specimen was yielded plastically under successively higher amounts of load and the resulting Lueders' lines were recored using oblique-incident light, etching, photoelastic coatings and brittle coatings. When the results from the various methods were compared, the authors found some advantages in the use of brittle coatings. This method was then used to record the Lueder's lines in beams under pure bending and simple bending, and in plates with notches and holes.     

Thermodynamic properties of superconducting 2H-NbSe2 exhibiting anisotropy and strong-coupling effect

A simple semi-empirical model which takes account of effects of the anisotropy and the strong coupling interaction in the expression of the energy gap together with the ellipsoidal energy spectrum is proposed to explain results of specific heat measurements on layer structure compound 2H-NbSe₂. The thermodynamic properties such as the electronic specific heat and the thermodynamic critical field deduced from this model give good agreements with experimental results.