A novel approach for the rapid decomposition of Actinide resin and its application to measurement of uranium and plutonium in natural waters

A rapid and robust procedure is described for the decomposition of Actinide resin permitting the routine application of this resin as a preconcentrator. Although the classical Fe(OH)3 precipitation is effective in scavenging actinides, the need for careful handling to recover the sticky precipitate makes the new method much more attractive. The known difficulty of decomposing Actinide resin, which is required prior to the subsequent separation of adsorbed actinides, is innovatively overcome by using a borate fusion attack. This procedure effectively solves the normally encountered problem by safely and speedily decomposing the resin in minutes rather than hours. The alternative and apparently simpler technique of direct ashing of the Actinide resin is not used since it leads to a residue that is not readily leachable. The new technique has been incorporated into a procedure for the isolation of Pu and U from natural water samples and their subsequent quantification by alpha spectrometry. The efficiency of loading of the elements onto Actinide resin has been tested using both batch and column-based approaches. The integrated method involving Actinide resin preconcentration, borate fusion, anion and UTEVA chromatography and electrodeposition provides limits of detection of 0.001 BqL(-1) and chemical recoveries in excess of 80% from groundwater and seawater samples as large as 5L. Comparative data, presented for the analysis of independently analysed river, borehole and surface run-off waters using both the described procedure and other competing techniques, show very good agreement.     

Pyridinium CH...anion and pi-stacking interactions in modular tripodal anion binding hosts: ATP binding and solid-state chiral induction

The preparation of two new tripodal "pinwheel" type anion hosts based on a triethylbenzene core and bipyridinium or ethylnicotinium arms is reported. The new materials bind anions via CH...anion interactions. Complexes with Br(-) and PF(6)(-) have been characterised by X-ray crystallography as both solvates in a pure form. In the bipyridinium host CH...F interactions to PF(6)(-) induce a chiral C(3) symmetric conformation that is disrupted in the hydrate. The compound is also selective for ATP(2-) in aqueous acetonitrile.     

The micro and semimicro determination of alkoxyl groups

An examination has been made of the sources of error associated with the determination of alkoxyl groups. Several features of other methods have been incorporated in a simple apparatus, and a modified procedure is presented for both the micro and semimicro determination of methoxyl and ethoxyl groups.     

Quantum cryptography without switching

We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates with increased bandwidths than previous schemes that only make single quadrature measurements. It also offers the further advantage of simplicity compared to all previous protocols which, to date, have relied on switching.     

The determination of strontium in coal ash by atomic absorption spectrophotometry

An atomic absorption spectrophotometric method for the determination of 0.01%–0.40% strontium in coal ashes is proposed. After suitable dissolution of the sample, 2000 p.p.m. of lanthanum are added to overcome interferences before the solution is atomized. The results obtained were compared with those obtained by flame-emission spectrophotometry. The method is rapid and no preliminary separations are necessary.     

Experimental demonstration of continuous variable polarization entanglement

We report the experimental transformation of quadrature entanglement between two optical beams into continuous variable polarization entanglement. We extend the inseparability criterion proposed by Duan et al. [Phys. Rev. Lett. 84, 2722 (2000)]] to polarization states and use it to quantify the entanglement. We propose an elaboration utilizing two quadrature entangled pairs for which all three Stokes operators between a pair of beams are entangled.