High-temperature behaviour of lithium borates:: Part I: Characterization and thermal stability

Nine compounds, namely Li₃BO₃, -Li₄B₂O₅, β-Li₄B₂O₅, Li₆B₄O₉, -LiBO₂, Li₂B₄O₇, Li₃B₇O₁₂, LiB₃O₅ and Li₂B₈O₁₃ in the Li₂O–B₂O₃ system have been synthesized and characterized. The unit-cell parameters, density and solubility in water at room temperature of all the compounds are reported. The densities of the compounds were found to be in the 1.90–2.50 g cm⁻³ range, while their solubility in water at room temperature was in the 0.91–8.64×10⁻² g cm⁻³ range. Determination of the thermal stability of the compounds by quenching and differential thermal analysis (DTA) showed that only -LiBO₂ and Li₂B₄O₇ retained their original symmetry up to their congruent melting at 1121 and 1188 K, respectively, in air.     

Cover-Incomparability Graphs of Posets

Cover-incomparability graphs (C-I graphs, for short) are introduced, whose edge-set is the union of edge-sets of the incomparability and the cover graph of a poset. Posets whose C-I graphs are chordal (resp. distance-hereditary, Ptolemaic) are characterized in terms of forbidden isometric subposets, and a general approach for studying C-I graphs is proposed. Several open problems are also stated.     

Extra dimension searches at hadron colliders to next-to-leading order-QCD

The quantitative impact of NLO-QCD corrections for searches of large and warped extra dimensions at hadron colliders are investigated for the Drell-Yan process. The K-factor for various observables at hadron colliders are presented. Factorisation, renormalisation scale dependence and uncertainties due to various parton distribution functions are studied. Uncertainties arising from the error on experimental data are estimated using the MRST parton distribution functions.      

Solution Chemistry of Europium(III) Aqua Ion at Micromolar Concentrations as Probed by Direct Excitation Luminescence Spectroscopy

Direct excitation europium(III) luminescence spectroscopy is used to study the speciation of aqueous europium(III) ions at micromolar concentrations and near neutral pH. The pH and concentration dependence of the europium(III) ⁷F₀→⁵D₀ excitation peak is consistent with the formation of both mononuclear and dinuclear europium(III) hydroxide complexes at pH 6.5. Luminescence intensity and lifetime quenching studies in the presence of Nd^III at pH 5.0 and 6.5 support the formation of a dinuclear complex at pH 6.5. Steady state excitation and time‐resolved luminescence spectroscopy are consistent with the formation of innersphere nitrate and fluoride complexes, but outersphere perchlorate and chloride complexes at pH 6.5 and 5.0.     

PDF and scale uncertainties of various DY distributions in ADD and RS models at hadron colliders

In the extra dimension models of ADD and RS we study the dependence of the various parton distribution functions on observables of Drell–Yan processes to NLO in QCD at LHC and Tevatron energies. Uncertainties at LHC due to factorisation scales in going from leading to next-to-leading order in QCD for the various distributions get reduced by about 2.75 times for a μ_F range 0.5Q<μ_F<1.5Q. Further uncertainties arising from the error on the experimental data are estimated using the MRST parton distribution functions.     

Determination of trace metals in sodium by electro-thermal atomic absorption spectrometry

Graphite-furnace atomic absorption spectrometry is used to analyze sodium metal after conversion to sodium nitrate. Chromium, Ni, Co, Cd and Pb have detection limits in sodium of 0.18, 0.48, 0.11, 0.02 and 0.48 μg g^-1; these are similar to the concentrations in nuclear-grade sodium, except for lead, which is below the detection limit. The behaviour of sodium nitrate, chloride and sulphate as matrices is compared.     

The CNO free radical and its isomerization in inert-gas matrices

The CNO free radical is generated in solid Ne by in situ photolysis of fulminic acid, HCNO. Its electronic spectra and photoisomerization to NCO are examined.     

The first three anisotropy constants of nickel

The technique of ferromagnetic resonance at 23 GHz has been used to determine the first three anisotropy constants of pure Ni down to 4.2K. A temperature and orientation dependent linewidth has also been observed.     

Residue-squaring iterative diagonalization method for perturbation problems

We present a new method for the evaluation of the change in eigenvalues due to a perturbation of strength λ. It is a fast converging iterative method which, at thenth step, gives results accurate to order (2 ⁿ⁺¹?1) in λ. Unlike the Rayleigh-Schrödinger perturbation theory in quantum mechanics, which becomes prohibitively cumbersome when carried to higher orders, the present method involves a routine which remains stralghtforward at all stages.