bluuebunny/crossref_metadata_2025 huggingface dataset:
States in 40Ca near 12 MeV Excitation from the 39K(p, g)40Ca Reaction
Authors: Sevior ME , Crawley GM , Sargood DG
Published: June 2013

Measurements of the 39K(p, ytOCa reaction in the region near 12 MeV show that none of the four resonances observed between 12�03 and 12�09 MeV excitation energy in 40Ca has In = 0+. If one of these states corresponds to the fj.f = 0 transition seen in the high energy (p, p') reaction at an excitation energy of 12�06�0�02 MeV, this suggests that the spin and parity of this state are 1 +.
A Modified Solar Collector Flow Factor
Authors: O'Keefe MJ , Francey JLA
Published: June 2013

The mean fluid temperature in a solar collector is often approximated by the average of the inlet and outlet temperatures. When this is done a simpler expression for the collector flow factor can be derived, the use of which permits the formal proof that collector efficiency will decrease with any maldistribution of fluid flow in the risers of the collector.
Theoretical and Experimental Techniques for the Determination of X-ray Anomalous Dispersion Corrections
Authors: Creagh Dudley
Published: June 2013

Theoretical and experimental techniques for the determination of the X-ray anomalous dispersion corrections f'(w, LI) and fl/(w, LI) are discussed. The results of experiments on metallic, ionic and covalently bonded materials typified by copper and nickel, lithium fluoride, and silicon respectively are compared with the theoretical predictions. Attention is drawn to deficiencies in both the experimental and the theoretical approaches.
The Anatomy of an Image
Authors: Moodie AF , Whitfield HJ
Published: June 2013

Following the approach employed by Mathieson in his analysis of an X-ray Bragg reflection, we dissect the images of the 3, 3 polymorph of CuAsSe and show that certain characteristic patterns which outline the structure are to be found in the lattice images of a wide range of tetrahedrally bonded species.
Scattering at the Positive Energy Bound States
Authors: Husain D , Suhrabuddin S , Awin AM
Published: June 2013

For a rank- n separable potential, some of the conditions for the existence of positive energy bound states are given and discussed. It has been shown that scattering can occur at positive energy bound states and only a particular type of them can be interpreted as zero-width resonances.
The Reaction Rate Coefficient for the Clustering of He to Li + at Low Centre of Mass Energies
Authors: Cassidy RA , Elford MT
Published: June 2013

A drift tube-mass spectrometer employing Bradbury-Nielsen grids and the method of Takebe et at. (1982) has been used to determine the reaction rate coefficient for the primary clustering reaction of He to Li + at 80 K at mean centre of mass energies from 10 to 15 meV. The influence of mass discrimination in experiments where reactions are studied by ion sampling of both parent and product ions is discussed.
Coherent X-ray Scattering by Co III
Authors: Glass R
Published: June 2013

The atomic scattering factor for the ground state of the cobalt ion, 3d7 4F, has been evaluated using nonrelativistic and 'relativistic-corrected' wavefunctions of varying accuracy. The importance of incorporating all types of electron correlation systematically within the valence subshell while keeping a fixed argon core is discussed. From the results presented, it appears that atomic scattering factors evaluated using Hartree-Fock wavefunctions are of sufficient accuracy for an atomic ion with an open-shell ground-state configuration.
Thermal Properties of Stabilized Zirconia at Low Temperatures
Authors: Collins JG , Collocott SJ , White GK
Published: June 2013

The linear thermal expansion coefficient a from 2 to 100 K and heat capacity per gram cp from 0�3 to 30 K are reported for fully-stabilized zirconia containing a nominal 16 wt.% (9 mol.%) of yttria. The heat capacity below 7 K has been analysed into a linear (tunnelling?) term, a Schottky term centred at 1�2 K, a Debye term (e~ = 540 K), and a small T5 contribution. The expansion coefficient is roughly proportional to T from 5 to 20 K and gives a limiting lattice Griineisen parameter 'Yo ::::: 5, which agrees with that calculated from elastic data.
Magnetic Reconnection in the Earth's Magnetotail
Authors: W Hones Jr Edward
Published: June 2013

Over the past few years satellite observations of the plasma sheet in the Earth's magnetotail during magnetospheric substorms have established beyond reasonable doubt that magnetic reconnection occurs in the magnetotail and that it plays a central role in the substorm process. The features seen at Earth by which substorms were originally identified (e.g. the auroras and geomagnetic disturbances) are simply superficial manifestations of a more fundamental physical process-the magnetosphere divesting itself of stored energy and plasma that was acquired earlier from the solar wind. It does so by shedding a part of its plasma sheet. This is accomplished by magnetic reconnection near the Earth that severs the plasma sheet, forming a plasmoid that flows out of the tail and that is lost to the solar wind. Recognition of the existence of plasmoids and our developing understanding of them have been important elements in confirming the occurrence of reconnection in the magnetosphere. In an analogous way, the best evidence for the occurrence of reconnection on the Sun has come from observations of closed magnetic configurations (plasmoids) in the solar wind and in the corona. But while magnetic reconnection is certainly the key ingredient in solar flares and substorms, analogies between them should not be carried too far, because there are basic differences in the environments in which they prevail and in the physical procesSes that lead to their occurrence.
The Sunspot Cycle and Solar Magnetic Fields. II. The Interaction of Flux Tubes with the Convection Zone
Authors: G Giovanelli Ronald
Published: June 2013

Mechanisms of interaction between flux tubes or ropes and the convection zone are examined insofar as they are relevant to the sunspot cycle. These include floating, transport, and the penetration of gas from outside the tubes. It is found that all previous studies contain one or more major errors of physics which render their conclusions invalid. The errors include invariably the assumption that Archimedes' principle is applicable to flux ropes, that gas entry can be disregarded, and usually that floating criteria depend solely or primarily on local phenomena. Some of the results presented here are explanations of (i) the transport of flux tubes by the slow observed poleward motions and the even slower systems which carry extensions of these tubes downwards to depths of ~ 150 Mm and then equatorwards; (ii) their magnetic field strengths ( ~ 104 G at a depth 10 Mm to (6-12) x 104 G at ~ 150 Mm); and (iii) the amplitudes of the torsional oscillation. Taken in conjunction with Part I, where the mechanism of polar field reversal is described and the variation of the phase of the torsional oscillation explained, all major cycle observations are accounted for in what turns out to be a new type of dynamo mechanism.
Is there a Connection between Local and Global (In-)Stability?
Authors: Eckhardt B , Louw JA , Steeb W-H
Published: June 2013

We review two criteria which have been used to predict the onset of large scale stochasticity in Hamiltonian systems. We show that one of them, due to Toda and based on a local stability analysis of the equations of motion, is inconclusive. An approach based on the local Riemannian curvature K of trajectories correctly predicts chaos if K < 0 everywhere, but�no further conclusions can be drawn. New (counter-)examples are provided.
Interpretation of Backscattered HF Radio Waves from the Sea
Authors: Naylor GRS , Robson RE
Published: June 2013

Radar oceanographers have long relied upon a simple diffraction grating model of the sea surface to explain the predominant features in the backscattered Doppler frequency spectrum. It is argued in this paper, however, that the ruled diffraction grating model with scattering localized to wave crests is incorrect and that a sinusoidal grating of period one-half the radio wavelength, with scattering from the entire surface, is the simplest representation of the sea surface which is consistent with both rigorous theory and experimental observation.
Low Temperate Zone Sporadic-E: Seasonal and Diurnal Variations at Rarotonga
Authors: Baggaley WJ
Published: June 2013

The seasonal variations of strong E s occurrence as a function of diurnal period have been obtained for the Pacific station of Rarotonga (21 0 .2 S). The seasonal characteristics depend markedly on local time with afternoon Es activity showing large deviations-equinoxial enhancements and summer peaks occurring before solstice-from those expected from the formation processes currently understood.
Parity Violation from SUSY Vertex Corrections in Deep Inelastic Scattering
Authors: CL Hollenberg Lloyd , HJ McKellar Bruce
Published: June 2013

Corrections to the eey and qqy vertices, at the one loop level, from intermediate supersymmetric (SUSY) states are calculated. The induced parity-violating interaction between electrons and nucleons is applied to the calculation of the lowest order SUSY contribution to the asymmetry in deep inelastic e + deuteron scattering in both the 'tree-breaking' (TB) and 'renormalisation-group' (RG) supergravity models. The results indicate that, for a wide range of sparticle masses, the SUSY contributions lie well within constraints implied by present measurements.
The Discrepancy in the Fermi Matrix Elements of the Isospin-forbidden 4+ ? 4+ ß- Decay of 46Sc
Authors: Saw EL , Yap CT
Published: June 2013

A large number of measurements have been made on the ')I-polarisation asymmetry coefficient A ~- y - for 4 + --+ 4 + --+ 2 + of the 46Sc --+ 46Ti decay. Presently, there are two adopted values of A yielding the Fermi nuclear matrix elements 1M F I = (0� 06 ~ g: 6~) xl 0 - 3 and (1 �4 � 0�3) x 10- 3, the latter being the more probable. Using a one-body spheroidal Coulomb potential with Nilsson wavefunctions, the theoretical value of M F is found to be 0�91 x 10 - 3 in good agreement with the experimental value of(I.4�0.3)xlO- 3.
Excited-state Quenching Phenomena in Weakly Ionised Nitrogen
Authors: Ernest A , Haydon SC , Elford MT
Published: June 2013

A number of studies of the ionisation behaviour of molecular nitrogen have revealed the importance of N 2(A 3L ;;) metastable particles which are created by direct electron impact excitation or cascade processes. More recent studies using cleaner gas samples have indicated that the ionisation current may be affected by the presence of a second metastable particle. The possible identity of this second metastable particle and the sensitivity of the ionisation current to its presence have been investigated by observing the changes in the pre-breakdown ionisation current as a function of the purity of the N 2 gas samples. Both the spatial and temporal behaviour of the ionisation current were observed. Particular care was required in this study to ensure that stable electrode surface conditions were obtained and the procedures adopted are described in detail. The addition of CO and H2 to the N 2 samples at the parts per million level confirmed the dominant quenching action of CO. Further consideration of the spatial growth of ionisation has demonstrated that an ionisation mechanism involving both N2(A 3L ;;) and N2(a' 1 L;;-) particles provides a plausible explanation for the observations and should be further investigated.
The Effect of the Flow Distribution on the Thermal Efficiency of a Solar Collector
Authors: O'Keefe MJ , Francey JLA
Published: June 2013

An isothermal one-dimensional flow model is used to calculate the flow distribution across the manifold of a flat plate solar collector in order to quantify the effect of a non-uniform flow distribution on the thermal efficiency for a variety of manifold geometries. The predictions of this flow model are found to compare favourably with measured isothermal flow distributions.
The 12C(a,?)16O Cross Section at Stellar Energies
Authors: Barker FC
Published: June 2013

An earlier calculation of the El contribution to the 12C(a, y) 160 cross section at stellar energies, which used R-matrix formulae with parameters chosen to fit 12C+ a phase shifts and the a spectrum from 16N {3 decay, is updated by including in the fit 12C(a, y) 160 cross section data. The E2 contribution is obtained by an R-matrix fit to 12C + a phase shifts and to data derived from 12C(a, y) 160 angular distribution measurements. Estimates of these contributions by others are discussed critically. It is suggested that the long-accepted value of the stellar cross section should be increased by a factor of about 2 rather than the factor 3-5 that has been proposed recently.
An Analysis of the 12C(16O, a)24Mg Reaction
Authors: Ahsan MH , Ahmad AAZ , Afzal SA
Published: June 2013

The angular distribution of a particles from the reaction 12C(160, a)24Mg was calculated, with the help of an a particle model, for the ground state of 24Mg at bombarding energies with 160 of 15�25,16�48,17�10,17�85,19�30,20�70 and 21�80 MeV. Calculated results were compared with experimental data and satisfactory agreement was obtained.
Monte Carlo Simulation of an Electron Swarm in an Argon-like Gas
Authors: Koura Katsuhisa
Published: June 2013

A Monte Carlo simulation (MCS) of an electron swarm in an argon-like gas (of atomic mass a.m.u.), with Golden's cross section with a very deep minimum, is presented in order to examine the breakdown of the validity of the conventional two-term expression for the transverse diffusion coefficient Dr indicated by Milloy and Watts. It is found that the MCS value of Dr approaches the two-term value much slower than other swarm parameters such as the drift velocity Wand the longitudinal diffusion coefficient ~. The discrepancy between the MCS and two-term values of Dr revealed by Milloy and Watts is attributable to the evaluation of Dr at the long transient (correlation) stage in the MCS. It is concluded that the two-term expressions for Dr and ~ (and other swarm parameters) are sufficiently accurate even for Golden's cross section with a very deep minimum.
Systematics of Gyromagnetic Ratios of the 21+ States in Even Ge Isotopes
Authors: Lampard GJ , Bolotin HH , Stuchbery AE , Doran CE , Byrne AP
Published: June 2013

The relative gyromagnetic ratios of the 2t states in 70,72,74,76Ge were measured simultaneously by me ns of the thin-foil, perturbed y-r yngular distribution technique utilising the transient hyperfine field manifest t nuclei of Ge ions rapidly traversing polarised Fe. The states of interest were Coulomb excited using 75-MeV 34S projectiles incident upon natural element l Ge t rget. The present results re comp red with previously reported measurements and collective model expectations.
Effect of Randomness in Layer Thickness on the Phonon Structure of Superlattices
Authors: Pang GD , Xiong SJ , Tsai CH
Published: June 2013

A new type of disorder may occur in artificial superlattices, arising from the randomness in the layer thicknesses. We treat here its effect on the phonon structure. A modification of the infinite order perturbation theory by Wu et aL (1974 a, 1974 b) serves well to give satisfactory solutions of the problem.
Observation and Analysis of Nanosecond Time-resolved r.f. Corona in Air and Comparison with N2
Authors: Sato N , Haydon SC
Published: June 2013

The onset ofr.f. corona and the subsequent development of intermittent and continuous breakdown phenomena have been investigated in air in the space between a hyperboloidal needle-point and plane electrode for pressures from 80 to 650 Torr. Detailed records of the spatio-temporal development of the plasma and the complementary nanosecond time-resolved spectral emissions, with high spatial resolution, provide comparisons with corresponding data previously reported for nitrogen. The significant differences in the behaviour of the two gases are identified and attributed to the dominant role of electron attachment processes in the space-charge modified electric fields in air.
Microstructure of High Temperature Superconductors of the Perovskite Type
Authors: Moodie AF , Whitfield HJ
Published: June 2013

Combined high resolution electron microscopy and convergent beam electron diffraction (CBED) of the same areas of crystals of Ba3La3Cu6014 reveals defects of various types including ordinary dislocations and polytypic intergrowths. This latter type is considered to be intimately associated with the performance of this material as a high temperature superconductor ..
Why Baryons are not Skyrmions
Authors: Cahill RT , Roberts CD , Praschifka J
Published: June 2013

We present a critical analysis of the Skyrmion model for baryons. Using model quantum field theories we determine the origin of meson chiral effective actions and show that Skyrmions, i.e. chiral topological solitons of these effective actions, cannot be related to baryons and that indeed Skyrmions in these models are unstable.
Charge Symmetry Breaking in Neutron-Proton Scattering above Pion Production Threshold
Authors: Niskanen JA , Thomas AW
Published: June 2013

We examine the effect of the coupled N.6. inelastic channel on charge symmetry breaking in the np system. Our calculation includes the effects of mass splitting for the nucleon and delta multiplets in the channel coupling potentials. The results suggest that such effects become increasingly important at about 500 MeV laboratory energy.
Advances in Synchrotron X-ray Polycrystalline Diffraction
Authors: Parrish William
Published: June 2013

The advantages of synchrotron radiation for X-ray polycrystalline diffraction are illustrated by a number of examples. The plane wave parallel-beam X-ray optics uses a Si(lll) channel monochromator for easy wavelength selection and a set of long parallel slits to define the diffracted beam. The constant simple instrument function and the high resolution symmetrical profiles (FWHM 0.05") greatly simplify the data analysis and add a new dimension to profile broadening studies. The geometry permits uncoupling the 6-26 sample-detector relationship without changing the profile shape and makes possible new applications such as grazing angle incidence depth analysis of thin films. The same instrumentation is used for high resolution energy dispersive diffraction (BOD) by step-scanning the monochromator. The resolution is two orders of magnitude better than conventional BOD and can be used at high count rates. The easy wavelength selection yields diffraction patterns with the highest PI B and permits anomalous scattering studies.
Pitfalls in the Evaluation of X-ray Diffraction Line Shape
Authors: Zorn Gerhard
Published: June 2013

The sources of errors in the analysis of X-ray diffraction profiles are described, and recipes are given to minimise or eliminate these errors. It is proposed that a sample at high temperatures is used as a standard. The influence of measurement statistics on the Fourier transform of deconvoluted functions is demonstrated through computer simulations. The necessity for smoothing procedures is stressed. It is shown how the parameter step width, number of sampling points, and position of origin for the Fourier transformation can be optimised, and thus a reliable basis can be created for the interpretation of the Fourier transform in terms of crystallite size, size distribution, and micros train.
X-ray Line Broadening Study on Shock-modified Zirconia
Authors: Morosin B , Graham RA , Zhang Y , Stewart JM , Hubbard CR
Published: June 2013

Zirconia (Zr02) powder compacts have been subjected to controlled, quantitative high pressure shock loading at peak pressures from 5-27 GPa and preserved for post-shock analysis. The overlapping broadened X-ray diffraction peak profiles have been separated by least-squares fitting procedures. The separate lines have been analysed in the usual manner to determine the residual lattice strain and the coherent crystallite sizes. Maximum modification effects are observed near 20 GPa with strain values near 3 x 10-3 and size values near 200 A.
Use of Full Diffraction Spectra, Both Experimental and Calculated, in Quantitative Powder Diffraction Analysis
Authors: K Smith Deane , G Johnson Jr Gerald , M Wims Andrew
Published: June 2013

The use of the full powder diffraction trace over a selected diffraction range for quantitative analysis has advantages over using single peaks in that it compensates for the effects of peak overlap and low levels of preferred orientation. Using a data base composed of experimental and calculated traces, the phase composition of an unknown may be determined by determining the least-squares best-fit sum of the appropriate data base patterns to the pattern of the unknown. Weight fractions are calculated from the pattern weighting factors using the reference-intensity-ratio method.
Quantitative Analysis of Phases in Zeolite Bearing Rocks from Full X-ray Diffraction Profiles
Authors: Taylor JC , Pecover SR
Published: June 2013

It is shown that quantitative analysis of zeolite phases in mineral mixtures can be performed using calculated whole-pattern X-ray diffraction profiles and Bragg-Brentano patterns. The method was tested on binary and ternary standard mixtures containing quartz, heulandite, chabazite and stellerite, and gave zeolite weight percentages correct to within a few per cent. Structure analyses of the zeolites were necessary to obtain good calculated profiles. The platy zeolites heulimdite and stellerite had severe preferred orientation problems, which were minimised experimentally by adding Al powder diluent and an epoxy resin, and regrinding. Analyses of field samples are also described.
Non-systematic Three-beam Effects in Dynamical Electron Diffraction and Their Use in Determination of Amplitude and Phase of Structure Factors
Authors: Marthinsen K , Matsuhata H , Hfier R , Gjfnnes J
Published: June 2013

The treatment of non-systematic multiple-beam effects in dynamical diffraction is extended. Expressions for Bloch wave degeneracies are given in the centrosymmetrical four-beam case and for some symmetrical directions. These degeneracies can be determined experimentally either as critical voltages or by locating the exact diffraction condition at a fixed voltage. The accuracy when applied to structure factor determination is comparable with the systematical critical voltage, namely 1% in UfT The three-beam case 0, g, h is treated as well in the non-centrosymmetrical case, where it can be used for determination of phases. It is shown that the contrast features can be represented .by an effective structure factor defined by the gap at the dispersion surface. From the variation in the gap with diffraction condition, a method to determine the three-phase structure invariant I\J = 9 + _ h + h _ 9 is given. The method is based upon the contrast asymmetry in the weaker diffracted beam and can be applied in Kikuchi, convergent beam or channelling patterns. Calculations relating to channelling in backscattering are also presented.
Effect of n-beam Interaction
Authors: Okazaki A , Ohe H , Soejima Y
Published: June 2013

Weak spurious intensities arising from the n-beam interaction (the multiple diffraction) often obscure the existence of screw axes or glide planes. It is pointed out that the n-beam interaction may also introduce� significantly different intensities to a set of crystallographically equivalent reciprocal lattice points. These problems can be solved by making IJI scanning measurements and, more definitely, by a comparison with the simulation based on the Soejima-Okazaki-Matsumoto (1985) formalism; some examples are shown. Since the influence on the intensity reaches 10% for strong reftections and more for weaker ones, a careful examination is essential for the accurate determination of F values.
An Investigation of r.f. Travelling Wave Current Drive Using the Model
Authors: Bertram WK
Published: June 2013

Previous experimental investigations into the use of travelling r.f. waves to drive steady toroidal currents in a toroidal plasma have shown that It, the amount of current driven, is strongly dependent on the ratio of the static toroidal magnetic field Bz, to the strength of the r.f. magnetic field BO). This dependence is characterised by an initial increase and subsequent decrease of It when Btl BfIJ increases. It is shown that this observed behaviour is entirely consistent with the behaviour predicted by the <i X B) current drive model. Results from .numerical computations using the <i X B) model show good quantitative agreement with the published experimental results.
High-Tc Superconductors: Evidence on the Electron?Phonon Interaction from Transport Measurements
Authors: Kaiser AB , Uher C
Published: June 2013

We discuss the interpretation of measurements of thermal conductivity, thermopower, Hall coefficient, resistivity and mapetorcsistance in hiJh-temperaturc superconductors. The thermal conductivity of YBa2 Cu3 07 shows an increase below the transition temperature 7;:, demonstrating the importance of the electron-phonon interaction in reducing the phonon current in the normal state. Many features of resistivity and thermopower can be interpreted in terms of conventional metallic models, although morc exotic interpretations have been proposed. We show how measurements on morc disordered samples should help resolve controversy regarding the interpretation of the electronic transport properties.
Effects of X-irradiation on the Principal Uranium Centre in Alkali Fluorides
Authors: Runciman WA , Srinivasan B
Published: June 2013

When fluorescing crystals of LiF and NaF containing hexavalent uranium and oxygen are X-irradiated the fluorescence is quenched and new absorption centres are created. There are strong absorption lines created at 562�8 nm in LiF: U, 0 and at 580�6 nm in N aF: U, O. These and other absorption lines have been studied by magnetic circular dichroism (MCD). A temperature independent MCD was observed, indicating an upper state degeneracy. A Fano antiresonance is observed in the absorption spectrum. No splitting was observed for the lines under uniaxial stress at 10 K. A model for these new centres is proposed.
Thermal Performance of Solar Collectors with EPDM Absorber Plates
Authors: O'Keefe MJ , Francey JLA
Published: June 2013

An experimental study of flat-plate solar collectors using ethylene, propylenediene monomer (EPDM) absorber plates is descn"bed. In spite of the high thermal resistance of this material the performance is found to compare well with metal absorbers and to be in agreement with the Hottel-Whillier-Bliss equation. There is, however, an observed increase in the heat loss coefficient for mass flow rates below a critical value.
Accuracy in Temperature Factor Determination in Powder Diffractometry
Authors: Kimmel G , Schreiner WN
Published: June 2013

The discrepancy between the temperature factors derived from X-ray powder diffraction and those derived from X-ray single crystal or neutron powder diffraction led us to look for additional causes of systematic intensity errors for powders. Integrated intensities of powder diffraction lines were carefully measured for selected materials using a Bragg-Brentano powder diffractometer equipped with an automatic divergence slit and a graphite monochromator. The measured intensities were compared with calculated intensities and significant systematic effects were observed which could not be related to structural sources, but were traced to instrumental sources. Use of an empirical angular dependence correction factor resulted in acceptably low R values. The instrumental factor couples strongly to the temperature factor by virtue of a similar angular dependence. Thus, reliable temperature factors cannot be obtained from commercial powder diffractometers unless the instrumental contributions are first removed.
The Knee of the Cosmic Ray Energy Spectrum
Authors: Clay RW
Published: June 2013

An examination is made of possible primary cosmic ray energy spectra which are consistent with observed air shower size spectra. At the size spectrum knee, it is necessary to have a very sharp primary spectrum break in order to be consistent with both the size spectrum and also air shower ftuctuations. Such a break may be due to energy loss at the cosmic ray source.
Consistent Description of Unbound States Observed in Scattering and Reactions
Authors: Barker FC
Published: June 2013

The unbound states of a nucleus C may be studied in elastic scattering A + a -+ C -+ A + a, and in reactions of the type B+b -+ C+c, in which C is an unstable product nucleus. Expressions for the scattering cross sections or phase shifts, and for the dependence of the reaction cross section on Ee, have been derived from R-matrix theory, and it is argued that consistent values of the R-matrix parameters should be used in describing the two types of data. This requirement has been disregarded, however, in a recent paper concerned with the 2+ states of SBe. On the other hand, support for the consistency argument comes from theoretical and experimental work done recently in Canberra on the low-lying states of SHe and sLi.
Hadronisation of QCD
Authors: Cahill RT
Published: June 2013

Functional integral calculus (FIC) methods are used to transform the meson-diquark bosonisation of quantum chromodynamics into a meson-baryon effective action description of the low energy states of QCD-the adronisation of QCD.
Investigation of E1 Strength in Coulomb Excitation of Light Nuclei
Authors: Barke FC , Woods CL
Published: June 2013

Contributions to the predominantly E2 Coulomb excitation of the first excited states of 6U, 7U, lOB, 11 B, 12C and 170 due to virtual E1 transitions through intermediate states are calculated using for all states shell model wavefunctions of the lowest admissible configurations, obtained with a realistic Hamiltonian. When harmonic oscillator single-particle wavefunctions are used, the contributions can be calculated rigorously but are generally less than the experimental values. Increases due to use of Woods-Saxon wavefunctions are estimated in a semi-quantitative way. For 170, the additional increase due to admixtures from higher configurations in the wavefunctions is also considered.
Magnetic Susceptibility of Neutron Matter Using Skyrme Forces
Authors: Das BK , Satpathy RK , Mishra IP
Published: June 2013

The energy per particle and magnetic susceptibility in neutron matter are calculated using the Skyrme and modified Skyrme interactions. Results show a kind of ferromagnetic transition beyond the Fermi momentum kn - 1 �0 fm-I. It is concluded that such behaviour is a general phenomenon instead of a result due to the choice of a given effective interaction
Linear Force-free Magnetic Fields and Coronal Models
Authors: Durrant CJ
Published: June 2013

The mathematical properties of linear force-free fields generated by the Helmholtz equation are reviewed, and the solutions in terms of spherical, cartesian and cylindrical coordinate systems are discussed. When only the normal component of the field on a single (photospheric) surface is available as a boundary condition, the solutions are not niquely determined. If further conditions are imposed, solutions may be unique or multiple or may not exist. The
X-ray Photoelectron Studies of High-temperature Superconductors: Evidence for the Importance of Alkaline Earth Metals
Authors: Dobson JF , Bocquet AE , Healy PC , Myhra S , Stewart AM , Thompson JG
Published: June 2013

All high�temperature superconducting ceramics so far studied contain alkaline-earth ions, and in all cases core-level X-ray photoelectron spectroscopy shows an anomalous low-binding energy peak from these ions. We argue that this may point to electron-rich alkaline earth layers. These should be highly polarisable, allowing them to facilitate uperconductivity by screening the repulsion between electrons and/or holes in the CuD layers.
Role of Flux Pinning in High Temperature Superconductors
Authors: Muller K-H , Macfarlane JC , Ricketts BW , Driver R
Published: June 2013

The critical state model with a pinning force independent of flux density is employed to interpret the meas.ured ac magnetic flux response and the weak critical current density of ceramic Y-Ba-Cu-O material. The intergranular (Josephson) vortex pinning is found to be about 108 times weaker than that in conventional type II superconductors.
Primordial Perturbations, Early Evolution and Dark Matter in the Universe
Authors: Lukash VN
Published: June 2013

The problem of primordial cosmological perturbations which gave birth to the large scale structure of the universe is analysed from the time of their origin up to the nonlinear formation of the structure. We show how classical gravity accounts for the generation of perturbations near the beginning of the cosmological expansion. Dark matter which governs the further development of perturbations in the early universe includes both heavy and light weakly interacting particles. Transfer functions of the adiabatic and isothermal modes of perturbations are investigated and some astrophysical applications are given.
The Clustering and Evolution of QSOs
Authors: Boyle BJ
Published: June 2013

Recent advances in instrumentation, particularly at the Anglo-Australian Telescope, have greatly increased the number of quaSi-stellar objects (QSOs) identified at faint magnitudes (B> 20 mag) and high redshifts (z> 2.2). As a result, significant progress has been made in the study of QSO clustering and evolution in the last two to three years. This paper reviews the results obtained and discusses their relevance to models of galaxy formation and the large-scale structure of the universe.
K-Capture in the Decay of 191Pt
Authors: Binarh HS , Singh Harjinder , Ghumman SS , Sahota HS
Published: June 2013

Relative K-capture probabilities to three levels of 1911r are determined from the decay of 191 Pt using the sum coincidence method based on summing of gamma rays and K X-rays in a single HPGe detector. The results agree with theoretical values. The electron-capture decay energy calculated using j3-decay properties to different levels belonging to the same rotational family is in agreement with the experimental value.
(e,2e) Studies of Atoms ? Some Recent Developments
Authors: Weigold Erich
Published: June 2013

Some recent work on (e,2e) collisions in atoms is reported. The first (e,2e) results on an excited target and also on an oriented target are discussed. Sodium atoms are pumped to the m/ = +1 state of the excited 3p state by 0"+ light from a laser. The (e,2e) measurements are then performed on this excited state. The results are in excellent agreement with the momentum density profile given by the 3p(m/ = 1) Hartree-Fock wavefunction. High resolution electron momentum spectroscopy measurements are reported for argon. The first momentum profiles for excited Ar ion states belonging to the 2po and 20e manifolds are obtained. The latter are entirely due to initial state correlations. Comparison is made with several many-body calculations. The importance of core quadrupole (10) excitations is demonstrated. Although the 2se manifold is dominated by final state correlations, the momentum profile to the 4s 2S ion state in the 2Se manifold also shows the influenee of initial state correlation effects. The third series of measurements examines correlations in the autoionising region of helium, encompassing the (2s2)1 S, (2s2p)3p, (2p2)! 0 and (2s2p)! P resonances, at 100, 200 and 400 eV incident electron energies. Measurements, with an energy resolution of 150 meV, were taken at a number of scattered electron angles over an extended range of ejected electron angles, encompassing both the binary and recoil regions. The data show very strong correlations between the resonance amplitudes and the direct ionisation amplitudes.
The Study of Surfaces Using Ion Beams
Authors: O'Connor DJ , King BV , MacDonald RJ , Shen YC , Chen Xu
Published: June 2013

The study of surfaces has progressed by the development of techniques which use different probing species in the form of electrons, ions and photons. Specialisation within the use of each probe has resulted in the subsequent development of methods of analysis tuned to obtain specific information about a surface. In this presentation the various uses of ion scattering spectrometry over a wide range of energies will be reviewed to illustrate how it has been successfully used to yield structural and compositional information of the surface atomic layer and the near surface region.
A Tomographic Investigation of Variations in the Excited State Populations of E x B Discharges
Authors: Garvie AM , Brennan MJ
Published: June 2013

A comparison of the spatial distribution of emissions from two molecular nitrogen electronic states of markedly different threshold energies has been made in a non self-sustained Townsend discharge in an ExB field. The spatial mapping has been performed using a combination of the 'photon flux' technique and reconstructive tomography. Observed differences in the spatial distribution of the two excited states are interpreted in terms of the gradient expansion of the energy distribution function. Comparisons made with the results of two-model simulations confirm this interpretation.
On the Importance of Self-interaction in QCD
Authors: Cahill RT
Published: June 2013

The electromagnetic self-energy of charged particles has remained a problem in classical as well as in quantum electrodynamics. In contrast here, in a review of the analysis of the chromodynamic self-energy of quarks in quantum chromodynamics (QCD), we see that the quark self-energy is a finite and a dominant effect in determining the structure of hadrons.
Models for Fermion Generations based on Five Fermionic Coordinates
Authors: Delbourgo R , Jarvis PD , Warner RC
Published: June 2013

We show that a limited range of options for fermion families may be neatly encompassed in a spacetime augmented by five Grassmann internal coordinates if we require that the superfields are self-dual in an 5U(5) sense. Amongst the possibilities is a family of just three standard model generations. We consider the nature of Higgs fields in this formalism and the form of possible gauge symmetries.
Model Investigation of a Soft X-ray Photoionisation Laser
Authors: Weigold AM
Published: June 2013

A soft x-ray laser system is proposed in which resonantly excited Mg atoms are rapidly photoionised by soft x�rays from a laser produced plasma, causing inversion and superfluorescent laser action at 24�7 nm in Mg II. Model calculations show that significant gains should occur when a moderately sized (10 J, 200 ps) 1064 nm pump laser is used.
Nonlinear Susceptabilities of Conjugated Organic Systems: Fused-ring Oligomers
Authors: Williams GRJ
Published: June 2013

The finite-field modified neglect of diatomic overlap (MNDO) molecular orbital technique has been used to calculate the second hyperpolarisability (the molel:ular counterpart to the macroscopic nonlinear susceptability tensor X3) for selected fused-ring oligomers. The fusedring segments are the active electro-optic units in ladder polymers and rigid-rod/flexible-chain copolymers that are under current investigation as polymeric materials with applications in ultrafast optoelectronic devices.
Quantum Mechanics, Real and Artificial Intelligence
Authors: Green HS , Triffet T
Published: June 2013

Some incompletely resolved problems in the quantal theories of measurement and observation are discussed with reference to Schrodinger's 'cat paradox' and the paradox of Wigner's friend. A simple version of the theory of measurement is presented, which does not completely resolve these paradoxes but suggests the need for an objective quantal description of the process of observation, and the formation of memory, of an event originating at the microscopic level, by an animal or artificial intelligence. A quantised model is then developed to simulate the function of the cerebral cortex in the formation of memory of sensory impressions, with macroscopic observables expressed in terms of parafermion operators of very large order. A letter from Schrodinger, which corrects some published versions of his paradox, is presented as well as a short account of the simulated formation of long-term memory by the model in an appendix.
Models for Supersymmetric Quantum Mechanics
Authors: Baake M , Delbourgo R , Jarvis PD
Published: June 2013

An algebraic view of supersymmetric quantum mechanics is taken, emphasising the couplings between bosonic and fermionic modes in the supercharges. A class of model Hamiltonians is introduced wherein the fermionic (bosonic) operators are canonical and the bosonic (fermionic) ones satisfy a Lie algebra (superalgebra) whose representation theory permits the complete solution of the model in principle. The kinematical symmetry of such models is also described. The examples of one and two bosonic models, with 5U(2) and 5U(3) dynamical algebras respectively, are analysed in detail.
Structural Stability of Perturbed mKdV Solitons
Authors: Roessler J
Published: June 2013

Periodic perturbations are applied to the homoc\inic orbits corresponding to solitons of the modified Korteweg-de Vries (mKdV) equation, which is significant in plasma physics and lattice models. It is observed that for certain distinct frequencies the homoclinic orbits do not split into stable and unstable manifolds, which means absence of horseshoes and chaos. The analysis is performed on a travelling wave reduced form of the mKdV equation both by standard application of the Melnikov method as well as numerical generation of POincare maps. In particular, the geometry of the homoclinic orbits and their structural changes under perturbations is investigated.
Dirac Equation in the Field of a Charged Cosmic String and in the Field of a Point Charge with Z > 137
Authors: Allen TJ , Tassie LJ
Published: June 2013

In both spherical and cylindrical coordinates, the radial Dirac equation can be written in the form of a Schrodinger equation with an effective potential. It is shown that the difficulties at r -+ 0 for the Dirac equation in the field of a point charge for Z > 137 are the same as those for the Schrodinger equation with a l/r2 potential. The effective potential is used to show that similar difficulties do not arise for the field of a line charge, so allowing the consideration of the motion of electrons in the field of a charged superconducting cosmic string without considering the internal structure of the string.
Positron?Lithium Inelastic Scattering with Polarisation Potentials
Authors: EI-Shabshiry M , EI Bakry SY , Moussa AH , Abdel-Raouf MA
Published: June 2013

Positron-lithium inelastic scattering is studied at positron energies ranging from 0�005 to 20 eV using the coupled static model. Two channels are open namely the elastic and positronium formation. The polarisation potentials of the Li atom in the first channel and that of the positronium atom in the second channel are taken into consideration in calculating the corresponding cross sections. The partial cross sections in each channel are calculated for eight values of the total angular momentum (0 ~.e ~ 7). In the elastic channel the total cross section Ull has its maximum value at the lowest energy, and decreases with an increase in positron energy Ki. The total positronium formation cross section has a small dip at 0�1 eV, and maximum value at Ki = 1 �4 eV, and then decreases smoothly with e+ energy. We compare our results with those of Ward et al. (1989) where positronium formation is ignored. The agreement in elastic cross sections improves with e+ energy, while the total collisional cross sections have the closest agreement at 1�0 eV. From this comparison, we find that positronium formation is important in the very low energy region, and the role of the excitation cross section increases steadily with e+ energy.
Radio Surveys and Large Scale Structure
Authors: Shaver PA
Published: June 2013

An analysis of the Molonglo Reference Catalogue indicates that significant departures from isotropy are present in the sky distribution of strong extragalactic radio sources. This has been shown to be due to local large scale structure, specifically a concentration to the supergalactic plane, which also influences the slope of the source counts. A study of the three-dimensional distribution of local radio galaxies shows that they are more strongly concentrated to the supergalactic plane than are optically�selected galaxies, and that the supergalactic concentration is more extensive than hitherto believed. It appears that radio galaxies (and clusters of galaxies) trace the 'skeleton' of large scale structure, about which normal galaxies are more loosely distributed. Thus, while large scale structure evidently complicates the interpretation of radio source counts, it appears that radiO surveys can be of value in exploring structures on the largest scales.
Guest Comment
Authors: J Buckman Stephen , T Elford Malcolm
Published: June 2013

The Joint Symposium on Electron and Ion Swarms and Low Energy Electron Scattering, a satellite meeting of the XVII International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC), was held at Bond University, Queensland in July 1991. This satellite meeting was the second occasion that two traditional ICPEAC satellites, The International Swarm Seminar series and the Electron-Molecule Scattering and Photoionisation satellite, were combined in order to bring together delegates from two largely diverse areas of low energy physics. The first such occasion was in 1985 at the time of the XIV ICPEAC at Stanford University.
Observations of Magnetic Fields
Authors: K Aitken David
Published: June 2013

A review of the methods of determining magnetic field parameters in astrophysical situations is presented. The role of radio observations is only briefly discussed because of recent review coverage, but a more detailed description is given of the optical and infrared polarisation produced by aligned dust grains, with particular reference to the relation between the grain alignment direction and the ambient magnetic field. Some recent results are outlined.
8-13 µm Spectropolarimetry of Star Formation Regions
Authors: M Wright Christopher
Published: June 2013

Amongst other things, mid-infrared spectropolarimetry provides information on the direction of the transverse component of a magnetic field. The polarisation is produced by dichroic emission and/or absorption by dust grains whose alignment is controlled by the ambient magnetic field. The observed position angle of the E vector allows the field direction to be determined. Here results are presented of 8-13 p,m spectropolarimetric observations of a number of star formation regions. Comparisons are made between the field direction observed and the Galactic field established by optical polarimetry of nearby field stars, and with the orientation of bipolar outflows and/or disks which are associated with some of these objects.
Observations of Southern Radio Galaxies at 1415 MHz
Authors: Jones PA
Published: June 2013

The structures of 23 strong radio galaxies, all with angular size larger than 3 arcmin, have been observed with the Fleurs Synthesis Telescope (FST) at 1415 MHz with a resolution of 22 arcsec. Spectral index differences within the sources were investigated by omparing 843 MHz images made with the Molonglo Observatory Synthesis Telescope (MOST) with FST images convolved to the same beam-size of 44 arcsec.