Interaction between free carriers,free excitons,and electron-hole drops in germanium

Under steady-state conditions, we have observed an increase of photo-conductivity in Ge at low temperature simultaneously with radiation from electron-hole drops. A set of rate equations for a 3-phase system of carriers, free excitons and drops are used to interpret the results. Values of the exciton-recombination coefficient and the lifetimes of the three phases are determined.     

Experimental energy band dispersions for a TiN(100) crystal

The energy band dispersions of TiN along the Γ-X symmetry line have been determined using a TiN(100) crystal and the angle-resolved photoemission technique combined with tunable synchrotron radiation. Using the direct transition model with a free-electron like final state, the dispersions are mapped out by varying the photon energy. The results are compared to an APW energy band calculation.     

Characterizing R-duality in Banach spaces

R-duals of certain sequences in Hilbert spaces were introduced by Casazza, Kutyniok and Lammers in 2004 and later generalized to Banach spaces by Xiao and Zhu. In this paper we provide some characterizations of R-dual sequences in Banach spaces.     

Determination of glycyrrhetinic acid in human plasma by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method has been developed for measuring 18 beta-glycyrrhetinic acid (GRA) in human plasma in the range of 0.1-3 micrograms/ml. The acetate ester of GRA is added to the plasma as an internal standard, plasma proteins are denatured with urea to release GRA, and the GRA and the internal standard are extracted in an ion-pairing solid-phase extraction process. An isocratic, reversed-phase HPLC separation is used, followed by ultraviolet absorbance detection at 248 nm. The results from the analysis of five GRA-fortified plasma pools show a mean relative standard deviation of 7% and are accurate to within 10%. With evaporative concentration of the extract, the limit of detection for GRA in plasma is approximately 10 ng/ml.     

Sorption of actinides on magnetite and goethite under reducing conditions

The present study investigated the sorption of ²³⁷Np, ²³⁹Pu and ²⁴¹Am onto magnetite and goethite as a typical iron corrosion product under reducing conditions as a function of solution pH, both in the presence and absence of CO₂ at 25°C. The sorption experiments were carried out for each actinide independently and for the simultaneous presence of the three actinides. Alpha-spectrometry of the liquid phase was performed to determine the equilibrium concentrations of the actinides after the sorption period. The sorption was strongly pH dependent. The sorption of ²³⁷Np onto iron minerals was enhanced by the presence of CO₂ to some extent. In other cases, the presence of CO₂ did not affect or prevented the actinides from sorption. There seems to be no simple tendency in the observed data under the conditions examined, probably due to the effects of aqueous and surface complexation reactions with carbonate ions.     

Solvated positron chemistry competitive positron reactions with halide ions in water

It is shown by means of the angular correlation technique that the binding of positrons to halides is strongly influenced by solvation effects. For aqueous solutions we find increasing values for the binding energies between the halide and the positron with increasing mass of the halide. This is contrary to the calculations of Cade and Farazdel for the vacuum case.     

Generation of coherent radiation at 61.6 nm by fifth harmonic conversion of radiation from a XeCl laser

Fifth harmonic conversion of radiation from a XeCl laser in Ar and Kr, generating radiation at 61.6 nm, is reported. Fifth power law variation of the generated energy with the pump energy is observed. The effects of continuum absorption are observed in the width of the phase matching peak in Ar.     

The synthesis of novel macrocyclic multidentate compounds from dioxodioic acids

A series of novel macrocyclic multidentate crown compounds have been prepared from a series of dioxodioic acids. The dioxodioic acids were prepared by treating various oligoethylene glycols or amines with maleic, succinic, citraconic, and glutaric anhydrides. The crown compounds were then synthesized from the dioxodioic acid chlorides obtained from the diacids and various oligoethylene glycols or ethylene diamine. The following macrocyclic compounds have been prepared: 1,4,9,12-tetraoxacyclohexadecane-5,8,13,16-tetrone ( 1 ); 1,4,7,10,15,18-hexaoxacyclodocosane-11,14,19,22-tetrone ( 2 ); 1,4-dioxa-9,12-diazacyclohexadecane-5,8,13,16-tetrone ( 3 ); 1,4,7-trioxa-12,15-diazacyclonoadecane-8,11,16,19-tetrone ( 4 ); 1,4,7,10-tetraoxa-15,18-diazacyclodocosane-11,14,19,22-tetrone ( 5 ); 4-benzyl-1,7,12,15-tetraoxa-4-azacyclonona-decane-8,11,16,19-tetrone ( 6 ); 1,4,7,12,15,18-hexaoxacyclodocosa-9,20-diene-8,11,19,22-tetrone( 7 ); and 9,21-dimethyl-1,4,7,12,15,18-hexaoxacyclodocosa-9,20-diene-8,11,19,22-tetrone ( 8 ) (Figure 1).