New mass spectrometric approaches to structural analysis in mixtures

Structural analysis of minor components in mixtures is a vital requirement in the development of any pharmaceutical compound. Mass spectrometry is uniquely able to give this kind of information on the trace amounts of material present as minor impurities in a drug substance. In this study we show that a combination of mass spectrometric analysers with different characteristics is an even more powerful approach with a higher chance of establishing a potential structure. In particular the advent of analysers capable of accurate mass measurement on small amounts of material has enabled structures to be proposed in situations where previously no real conclusions could be made. Copyright 1999 John Wiley & Sons, Ltd.     

Rational matrix approximation with a priori error bounds for non-symmetric matrix Riccati equations with analytic coefficients

In this paper the exact solution of the non-symmetric matrixRiccati equation with analytic coefficients is approximatedby a rational matrix function with a prefixed accuracy. Thisrational matrix function is locally defined as the exact solutionof a Riccati problem with matrix polynomial coefficients obtainedby truncation of the Taylor expansions of the matrix coefficientsof the original problem.     

The observation of a superdeformed structure in82Y

The⁵⁸Ni(³⁰Si,αpn)⁸²Y reaction at a beam energy of 134 MeV was used to populate the odd-odd nucleus⁸²Y and coincidentγ rays depopulating high spin states in the evaporation residues were detected with the EUROGAM Phase 2 array. A superdeformed structure has been observed with an intensity of 1.5±0.5%. The cascade of 9 coincidentγ rays has consecutive energy spacing of ～160 keV. This corresponds to a dynamic moment of inertia which is almost constant at approx mately 25h ² MeV^?1. The band is interpreted as a signature=0, negative parity SD band with aπ5¹ V5² intrinsic intruder configuration.     

Combined compact difference method for solving the incompressible Navier–Stokes equations

This paper presents a numerical method for solving the two‐dimensional unsteady incompressible Navier–Stokes equations in a vorticity–velocity formulation. The method is applicable for simulating the nonlinear wave interaction in a two‐dimensional boundary layer flow. It is based on combined compact difference schemes of up to 12th order for discretization of the spatial derivatives on equidistant grids and a fourth‐order five‐ to six‐alternating‐stage Runge–Kutta method for temporal integration. The spatial and temporal schemes are optimized together for the first derivative in a downstream direction to achieve a better spectral resolution. In this method, the dispersion and dissipation errors have been minimized to simulate physical waves accurately. At the same time, the schemes can efficiently suppress numerical grid‐mesh oscillations. The results of test calculations on coarse grids are in good agreement with the linear stability theory and comparable with other works. The accuracy and the efficiency of the current code indicate its potential to be extended to three‐dimensional cases in which full boundary layer transition happens. Copyright © 2011 John Wiley & Sons, Ltd.     

Study of 170,171,173Ta isotopes at high spinṡ

High-spin data are presented for ¹⁷⁰Ta and ¹⁷¹Ta for the first time, and the known level scheme of ¹⁷³Ta is extended to higher spins. Anomalies found in the crossing frequencies for the alignment of a pair of neutrons are considered. At high spin a large and constant value of J⁽²⁾, with J⁽²⁾ > J⁽¹⁾, is found for two ¹⁷¹Ta bands and the implications of this are discussed. The πi_13/2 [660]1/2⁺, α = + 1/2 orbital is identified as it crosses the rotational band built on the [402]5/2⁺, α = + 1/2 orbital in ¹⁷¹Ta. Magnetic transition probabilities obtained from measured branching ratios show the effects of the aligning pair of neutrons and the spectator orbital. The data are interpreted using cranked shell-model calculations and a semiclassical vector-coupling scheme developed by Donau and Frauendorf.