Determination of various inorganic anions and organic acids in the atmospheric particulate matter using capillary zone electrophoresis with indirect UV detection

Capillary zone electrophoresis with indirect UV detection was developed for the simultaneous analysis of inorganic anions and organic acids using a mixed solution of 2,6-pyridinedicarboxylic acid and cetyltrimethylammonium hydroxide as the background electrolyte (BGE). The parameters which influence the separation, such as indirect UV detection wavelength, BGE conditions, applied voltage and extraction conditions were investigated. Thirteen inorganic anions and organic acids were detected within 20 min. The calibration curves of each analyte were linear with correlation coefficients greater than 0.991. The relative standard deviations (n = 10) of the peak areas ranged from 0.6% to 3.3%. The detection limits for these species ranged from 0.4 to 1.4 mg/L at a signal-to-noise ratio of 3. The recovery rate of each analyte was more than 80% under optimised extraction conditions, except for nitrite. The proposed method was applied towards the analysis of inorganic anions and organic acids in the atmospheric particulate matter using an Andersen sampler. The particle size of the particulate matter was determined, but not the size of the anions.     

LPE-like growth of YIG ferrimagnetic thin films by pulsed laser ablation with molten droplets

Yttrium iron garnet (YIG) films were grown by pulsed laser ablation (PLA) on (111) Gadolinium Gallium Garnet (GGG) substrates. The second harmonic of YAG laser (532 nm) with a high laser fluence was employed to produce YIG droplets efficiently. It was found that YIG films prepared at RT substrates have a large number of solidified droplets of various sizes. Highly oriented YIG crystals were grown on the (111) GGG substrate heated at 860 °C by PLA using a large number of molten droplets, suggesting an LPE-like growth. This YIG film shows a small ferrimagnetic resonance linewidth of 7.5 Oe. This value is quite small for films prepared by vapor-phase epitaxy techniques.     

Anion exchange in the channels of a robust alkaline earth sulfonate coordination network

The barium sulfonate network presented herein, [[Ba2(L)(H2O)5]Cl]infinity (1), represents the first metal sulfonate compound to possess a cationic framework. The network is layered with channels between pillaring ligands in which chloride ions reside. Compound 1 contracts slightly upon dehydration but retains its overall structural motif to 420 degrees C. Significantly, the chloride ions of the structure can be exchanged in 80% yield for fluoride ions in a facile manner. This exchange is quantified by elemental analyses, gravimetric determination, and 19F NMR spectroscopy. Confirmation of retention of structure is provided by standardized powder X-ray diffraction experiments. This last point is notable as the F-analogue of the structure is not attainable by a direct synthesis. These results illustrate one of the hallmark features of supramolecular chemistry, that a robust and functional framework can result through cooperative interactions between more weakly interacting units.     

Measurement of enantiomeric excess using molecularly imprinted polymers

[reaction: see text] A new method is presented for the measurement of enantiomeric excess (ee) utilizing molecularly imprinted polymers (MIPs). The method is demonstrated to be accurate and rapid, as the ee values can be calculated from straightforward concentration measurements. The MIP-based assay can also be adapted to measure the ee of samples of differing initial concentrations.     

Control of light pulse propagation with only a few cold atoms in a high-finesse microcavity

Propagation of a light pulse through a high-Q optical microcavity containing a few cold atoms (N<10) in its cavity mode is investigated experimentally. With less than ten cold rubidium atoms launched into an optical microcavity, up to 170 ns propagation lead time ("superluminal"), and 440 ns propagation delay time (subluminal) are observed. Comparison of the experimental data with numerical simulations as well as future experiments are discussed.     

Surface-enhanced emission from single semiconductor nanocrystals

The fluorescence behavior of single CdSe(ZnS) core-shell nanocrystal (NC) quantum dots is dramatically affected by electromagnetic interactions with a rough metal film. Observed changes include a fivefold increase in the observed fluorescence intensity of single NCs, a striking reduction in their fluorescence blinking behavior, complete conversion of the emission polarization to linear, and single NC exciton lifetimes that are >10(3) times faster. The enhanced excited state decay process for NCs coupled to rough metal substrates effectively competes with the Auger relaxation process, allowing us to observe both charged and neutral exciton emission from these NC quantum dots.     

Electronic structure of the trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta)

The low-energy electronic structure of the nearly optimally doped trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta) is investigated by angle-resolved photoemission spectroscopy. The normal state quasiparticle dispersion and Fermi surface and the superconducting d-wave gap and coherence peak are observed and compared with those of single- and bilayer systems. We find that both the superconducting gap magnitude and the relative coherence-peak intensity scale linearly with T(c) for various optimally doped materials.