A critical appraisal of the use of branched capillaries in analytical flame spectroscopy

The operating pressure of a pneumatic nebulizer has been measured. The rsult has been used to explain the problems associated with the variation in flame spectroscopy signal with sample position when a capillary T piece is used for continuous addition of releasing agent. The way to minimize this variation is outlined.     

On the dynamics of itinerant electron magnets in the paramagnetic state

It is shown how disordered local-moment states, in a metal such as Fe, may be stabilized by constraining magnetic fields. Effective interaction parameters between moments are defined in terms of spin density functional theory. On removing the constraints the moments initially precess but then decay rapidly, the latter process leading to an energy width of S(q, ω) at large q of order $\text{(k}{}_{\mathrm{B}}\text{T}{}_{\mathrm{C}}\text{W)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, where T_C is the Curie temperature and W is the width of the d-band. T he consequences for neutron scattering experiments are discussed and the rather different case of Ni is considered.     

Phase diagram of the tetramethylammonium heptadecafluorononanoate (TMAHFN)/D2O system as determined by 2H and 14N NMR

The high resolution phase diagram of the tetramethylammonium heptadecafluorononanoate (TMAHFN)/D₂O system has been mapped out using ²H and ¹⁴NNMR spectroscopy. The ¹⁴N quadruple splittings are more than an order of magnitude larger than corresponding ²H splittings, while the line widths are only two to three times larger. Thus, ¹⁴NNMR offers an order of magnitude improvement over ²H NMR in the resolution of the spectra from coexisting phases. The ²H spectra of samples in biphasic regions are often complicated by chemical exchange of D₂O molecules between coexisting phases, particularly at low TMAHFN concentrations. Analysis of the ²H line shapes of a TMAHFN/D₂O sample with a weight fraction of TMAHFN of 0.230 obtained at various times following cooling of the sample into the isotropic/nematic biphasic region shows that the mean diameter for the dispersed nematic droplet grows from about 7 to about 26 μm over a period of 2 h. At a mean droplet size of 7 μm the exchange of TMA⁺ ions between the coexisting phases is slow on the NMR time-scale and exchange effects are not observed in ¹⁴N spectra. The TMAHFN/D₂O phase diagram exhibits the generic form of those of the CsPFO/water and APFO/D₂O systems, which are the only other systems composed of stable discotic micelles for which high resolution phase diagrams are currently available, but the nematic phase is displaced to smaller TMAHFN concentrations. Specifically, a discotic nematic phase N_D⁺, intermediate between an isotropic micellar phase I and a lamellar phase L, exists for weight fractions of TMAHFN between 0.149 (φ = 0.105) and 0.420 (φa = 0.325) and temperatures between 277.3 and 327.6 K.     

Raman study of the O2F2 + VF5 reaction: Isolation and identification of an unstable reaction intermediate

The reaction of O₂F₂ with polymeric VF₅ in the temperature range -119 to -78°C leads first to the reaction intermediates

. On increasing the temperature of this intermediate, a new compound O⁺₂V₂F^-₁₁ is formed which in turn decomposes rapidly at room temperature. Raman studies of these species as well as of O₂F₂(solid), VF₅, KVF₆, KV₂F₁₁, CsVF₆ and CsV₂F₁₁ are reported and discussed.     

A new synthesis of indolo[2,3-α]quinolizidine derivatives: a formal total synthesis of (±)-geissoschizine

A stereospecific elimination process has been developed for introducing the E-ethylidene group in a transformation of tryptamine into methyl (±)-geissoschizoate.     

Mathematical foundations of quantum field theory: Fermions,gauge fields,and supersymmetry part I: Lattice field theories

In this paper we explore the mathematical foundations of quantum field theory. From the mathematical point of view, quantum field theory involves several revolutions in structure just as severe as, if not more than, the revolutionary change involved in the move from classical to quantum mechanics. Ordinary quantum mechanics is based upon real-valued observables which are not all compatible. We will see that the proper mathematical understanding of Fermi fields involves a new concept of probability theory, the graded probability space. This new concept also yields new points of view concerning ergodic theorems in statistical mechanics.     

Polarisation parameters in neutral pion photoproduction

The polarisation parameters Σ, P and T have been measured for the process γp→π⁰p in the photon energy range 1300–2100 MeV and c.m. angles between 30° and 110°, in an experiment with a polarised beam and polarised target. The results are compared with a recent theoretical analysis which fits data from threshold to 16 GeV. The new data are in general agreement with the analysis, but with some significant discrepancies in detail.     

Analysis of 2ν2, ν1, and ν3 of H2Se

We have run the high-resolution infrared absorption spectrum of 2ν₂, ν₁, and ν₃ of H₂Se in the region 5.2 to 3.8 μm. We have identified and fitted approximately 520 transitions in 2ν₂, 930 transitions in ν₁, and 620 transitions in ν₃. Included are transitions from the isotopic species containing selenium isotopes 82, 80, 78, 77, and 76. Using Typke's rotational Hamiltonian, we analyzed all isotopic species simultaneously. Ground-state constants were determined from a simultaneous least-squares fit of 879 distinct ground-state combination differences formed from our data and 109 microwave transitions. Upper-state constants were obtained from least-squares fits of our spectral lines analyzing 2ν₂ as a single noninteracting band and analyzing the Coriolis interacting bands ν₁ and ν₃ simultaneously, keeping the ground-state constants fixed.     

The turbulent flow of non-Newtonian fluids in the absence of anomalous wall effects

For Newtonian fluids, the engineering predictions for pressure drop in turbulent pipe flow are well established. However, in the case of non-Newtonian liquids, only a few design techniques have been proposed and these do not share a common basis with the approach for Newtonian systems. This present work attempts to provide a common basis for both Newtonian and non-Newtonian systems in situations where anomalous wall effects are absent. Previously published experimental data suggest that if the Reynolds number is calculated on the basis of the apparent viscosity at the wall then the standard Newtonian correlations can be used for the prediction of pressure drop. The use of the wall viscosity in defining the Reynolds number also serves as a test for anomalous behaviour. Any departure of the experimental data from the Newtonian turbulent friction factor correlation indicates anomalous behaviour.