bluuebunny/crossref_metadata_2025 huggingface dataset:
A Search for Ultra-high-energy Gamma-ray Emission from Binary X-ray Systems
Authors: Edwards PG , Ciampa D , Clay RW , Patterson JR
Published: June 2013

Observations have been made with the Buckland park air shower array over a two-year period from June 1984. We have examined events from the directions of six binary X-ray systems to search for any periodic component associated with ultra-high-energy gamma-ray emission above a threshold energy of -9xl014 eV. No statistically significant excess has been found and upper limits to the individual fluxes are presented.
A VLA Survey of Rich Clusters of Galaxies. I. Whole-cluster Maps, Source List and Source Statistics
Authors: Slee OB , Perley RA , C Siegman Betty
Published: June 2013

We have surveyed 58 fields near rich clusters of galaxies with the Very Large Array using scaled arrays in the B/C and/or C/O configurations at 1�5 GHz and 4�9 GHz. The fields were centred on steep spectrum sources in or near clusters that were earlier surveyed with lower resolution telescopes. The whole-field maps at 1�5 GHz are given and a list of 940 sources with 1�5 GHz flux densities down to -1 mJy is presented. Spectral indices of sources within 5' of the field centres are given. Complete flux-limited samples of sources are used to establish a criterion for cluster membership. Sources with total 1�5 GHz flux density >20 mjy and closer to the cluster centre than 0�28 of the cluster radius (a total of 57 sources) are accepted as cluster members.
Acquisition of Powder Diffraction Data with Synchrotron Radiation
Authors: Cox DE , Toby BH , Eddy MM
Published: June 2013

There was a typographical error on page 120: The treatment '�X2 = 0' should read '�X2 = 00'.
The Great Attractor ? A Cosmic String?
Authors: Mathewson DS
Published: June 2013

A brief review is made of the observational work on large-scale streaming motions in the Local Universe. There is considerable controversy as to whether the Great Attractor model of these streaming motions is correct. Preliminary results are presented of a southern sky survey of spiral galaxies to measure their peculiar velocities using the Tully-Fisher relationship. The region of strong peculiar motions has an elongated shape some 80� in angular extent centred roughly on the Great Attractor enclosing the brightest parts of the supergalactic plane. The peculiar velocities reverse in sign at a distance of 4000 km S-i which is conclusive evidence that such a dominant attracting region exists at that distance. However, there is little evidence of galaxies associated with this attracting mass and most galaxies appear to be participating in the streaming motions. The conclusion is that the attractor is largely invisible. It is proposed that a large moving loop of cosmic string is responsible for the peculiar velocities of the galaxies.
Soliton Characteristics at the Critical Density of Negative Ions in Ion-beam Plasmas
Authors: Das GC , lbohanbi Singh Kh
Published: June 2013

By using the reductive perturbation technique, ion-acoustic waves are studied in a generalised multicomponent plasma. The multiple ions modify drastically the characteristics of the solitary waves. In particular, the negative ions have a critical density at which the nonlinearity of the Korteweg-deVries (K-dV) equation vanishes and the ion-acoustic solitary wave is seen to be described by a modified K-dV (mK-dV) equation. Using higher order nonlinearities, the non-uniform transition of the K-dV equation to the mK-dV equation along with the conservation of the Sagdeev potential is described. Theoretical observations on the existence of the solitary waves, as expected, could be of interest in laboratory plasmas
Annual Reconstruction of the Solar Cycle from Atmospheric 14C Variations
Authors: Murphy JO
Published: June 2013

Initially, the rise and fall components of the ll-year solar sunspot cycle are approximated by separate least-squares polynomials for four cycle classifications, which are determined by the magnitude of the average of the annual sunspot numbers per cycle. Following, a method is formulated to generate detailed reconstruction of the annual variation of a solar cycle based on this cycle average, and the results obtained for cycles -4 through to 21 are compared with the annual Zurich values. This procedure is then employed to establish annual sunspot numbers using published average cycle values obtained from atmospheric carbon 14 variations, which have been derived from the chemical analysis of tree ring sections. The reconstructed sequences are correlated with the observed cycle values and with tree ring width index chronologies which exhibit a significant II-year periodicity. It is anticipated that the long carbon 14 records and parallel dendrochronological data could be employed to obtain a more detailed portrayal of previous periods of strong solar activity than that given by current estimates based on historical records.
Electronic Structure of Atoms, Molecules and Solids from (e,2e) Studies
Authors: McCarthy IE
Published: June 2013

The (e,2e) reaction on atoms can be described quite well in most of kinematic space by distorted-wave theories of varying sophistication. In some regions it is necessary to obey the newly-discovered boundary condition for three charged particles. The understanding enables us to recognise a kinematic region where the reaction is sensitive only to the target-ion structure. Single-particle and electron-correlation information has been discovered for a wide range of atoms and molecules. The understanding of solids is developing.
Effects of Diffraction on the (e,2e) Reaction in Crystals
Authors: Allen LJ , McCarthy lE , Maslen VW , Rossouw CJ
Published: June 2013

An expression is derived for the (e, 2e) differential cross section of a crystal, with allowance for dynamic diffraction of both the incident and outgoing electrons, all of which are assumed to be fast. Conditions for unique momentum determination on the one hand or for maximum enhancement of the (e,2e) signal on the other are discussed.
The Growth of Semiconductor Thin Films Studied by RHEED
Authors: Price GL
Published: June 2013

Recent developments in the growth of semiconductor thin films are reviewed. The emphasis is on growth by molecular beam epitaxy (MBE). Results obtained by reflection high energy electron diffraction (RHEED) are employed to describe the different kinds of growth processes and the types of materials which can be constructed. MBE is routinely capable of heterostructure growth to atomic precision with a wide range of materials including III-V, IV, II-VI semiconductors, metals, ceramics such as high Tc materials and organics. As the growth proceeds in ultra high vacuum, MBE can take advantage of surface science techniques such as Auger, RHEED and SIMS. RHEED is the essential in-situ probe since the final crystal quality is strongly dependent on the surface reconstruction during growth. RHEED can also be used to calibrate the growth rate, monitor growth kinetics, and distinguish between various growth modes. A major new area is lattice mismatched growth where attempts are being made to construct heterostructures between materials of different lattice constants such as GaAs on Si. Also described are the new techniques of migration enhanced epitaxy and tilted superlattice growth. Finally some comments are given On the means of preparing large area, thin samples for analysis by other techniques from MBE grown films using capping, etching and liftoff.
Auger Electron Spectra of Molecules: The First Row Hydrides
Authors: Larkins FP , Tulea LC , Chelkowska EZ
Published: June 2013

A semi-empirical molecular orbital approach primarily developed to predict the Auger energies and transition rates associated with complex polyatomic molecules has been evaluated by reference to the first row hydrides. For this suite of molecules, spanning a range of symmetry classes, high resolution experimental spectra and ab initio energy calculations are available for comparison. The method proposed provides a good first estimate for transition rates. Relative Auger energies are less satisfactory, especially when electron correlation effects are strong. Absolute kinetic energies are too low, principally due to the neglect of electronic relaxation. The usefulness of the approach is mainly for the interpretation of spectra for larger systems where ab initio calculations are not readily accomplished. A need for further experimental measurements obtained using photoelectron-Auger electron coincidence studies is identified to remove uncertainties associated with the extent of satellite contributions present in all the spectral profiles so far recorded. In the present work the satellite contribution to the methane Auger spectrum is estimated to be 16% of the total intensity compared with an earlier estimate in the literature of 49%.
Anisotropy Parameters and Adiabatic Approximations for Two-electron Atoms and lons
Authors: Macek Joseph
Published: June 2013

In dynamial processes atomic systems evolve from a condensation region at small distances where all particles are close together to an asymptotic region where some of the constituent particles are free and accessible to measurement. This dynamical evolution is characterised by the Jost matrix. Evaluation of the Jost matrix generally involves complex calculations, but considerable simplification is achieved when the evolution can be described in terms of adiabatic or diabatic potential curves. For low energy ion-atom and atom-atom collisions standard molecular potential curves have long been used. For low energy electron-atom scattering and photo-ionisation similar molecular-like potential curves have been proposed. There is no a priori justification for the adiabatic approach in these latter systems, thus confrontation with experiment is crucial for further development of this theory. Anisotropy parameters represent a particularly appropriate probe of the various adiabatic representations. This is illustrated by studies of photo-ionisation of helium at the n = 2 threshold. Potential curve crossings are important here and their relevance to the anisotropy parameters is illustrated
X-ray Diffraction Investigation of Epitaxial Layers of CdTe on Sapphire
Authors: W Stevenson Andrew , N Pain Geoff
Published: June 2013

The anomalous scattering of X-rays has been used to determine the polarity of CdTe epitaxial layers on sapphire. The results for two samples are presented, one of (111) orientation ('A face'), the other of (III) orientation (,B face'). The (III) layer is twinned, the two twin species being related by a 180� rotation about the [1111 axis. The twin fraction shows considerable variation for different positions on this sample, and must be taken into account when analysing the integrated X-ray intensities, in order to get meaningful Bijvoet ratios. The polarities of the two twin species are found to be the same.
Fabrication of Superconducting YBCO Thin Films on YSZ Substrates
Authors: Bailey A , Alvarez C , Puzzer T , Matthews DN , Sealey K , Russell CJ , Taylor KNR
Published: June 2013

In the title and running head of this paper. YBCO thin films should read YBCO thick films.
Pseudo-state Close Coupling in Electron?Atom Collisions
Authors: Stelbovics AT
Published: June 2013

In the last decade the role and nature of pseudo states applied to scattering problems has become better understood. The J-matrix technique has provided a direct physical interpretation for the pseudo states. Recent work in constructing and applying pseudo-state expansions based on analytic techniques is reviewed and convergence questions relating to the use of such expansions in the close-coupling equations are addressed.
Electron Scattering from Copper
Authors: Teubner PJO
Published: June 2013

A measurement of the total cross section for the excitation of the 42p state in copper by 60 eV electrons is described. These relative measurements are converted into absolute values by a generalised oscillator strength formalism which is also described. The result agrees very favourably with that predicted by a four state close coupling calculation, but is about a factor of three smaller than the previous measurement of Trajmar et al. (1977).
Feynman Rules for Magnetised Spin-O Bosons
Authors: Rowe ET
Published: June 2013

Solutions of the Klein-Gordon equation are given in the Landau and cylindrical gauges and these are used to calculate explicit forms of the vertex function. From an S-matrix expansion analogous to the spin-i case we obtain the Feynman rules for magnetised spin-O particles: the major differences between the spin-i and spin-O cases are the explicit forms of the respective vertex functions and the addition of a two-photon vertex in the spin-O case. This additional vertex makes possible a whole new class of Feynman diagrams.
Electron Spin Resonance of V4+(VO2+) in Beryl
Authors: Hutton DR , Darmann FA , Troup GJ
Published: June 2013

Synthetic Australian Biron beryl coloured green by vanadium was irradiated with a dose of 10 kGy of 137Cs y rays. The reSUlting ESR spectrum has been modelled as being due to 12 equivalent V02+ centres, each arising from a complex formed from the substitution of V3+ in the beryl aluminium octahedral site, together with electron loss and motion towards a nearest neighbour oxygen. Each centre can be fitted to an axial spin Hamiltonian
Cylindrical and Spherical Solitons at the Critical Density of Negative Ions in a Generalised Multicomponent Plasma
Authors: Das GC , Ibohanbi Singh Kh
Published: June 2013

Propagation of nonlinear ion-acoustic waves in generalised multicomponent plasmas bounded by cylindrical and spherical geometries is investigated. At the critical density of negative ions where the nonlinearity of the Korteweg-deVries (K-dV) equation vanishes, the ion-acoustic solitary wave is described by a modified K-dV (mK-dV) equation. It is also emphasised that near the critical density neither the K-dV nor mK-dV equation is sufficient to describe fully the ion-acoustic waves and thus there is a need to derive a further mK-dV (fmK-dV) equation in the vicinity of this critical density. Furthermore, the amplitude variations of the K-dV and mK-dV solitons depending on the limitations of geometrical effects are also discussed, emphasising that the results could be of interest for diagnosing the soliton properties of laboratory plasmas.
Design of Support Pillar Arrays in Flat Evacuated Windows
Authors: Collins RE , Fischer-Cripps AC
Published: June 2013

Flat evacuated glazing consists of two plane sheets of glass separated by a narrow evacuated space. These structures must incorporate an array of support pillars in order to maintain the separation of the glass plates under the influence of atmospheric pressure forces. A design procedure is outlined for determining the dimensions of this pillar array. Two important constraints in the design process are the mechanical tensile stress on the outside of the glass plates near the pillar, and the thermal conductance through the array of support pillars. A third constraint arises because of stress concentration near the pillars on the inside of the window. Evacuated windows having usefully low values of thermal conductance through the pillar array and tolerably small levels of exterior tensile stress can only be produced if large stresses exist on the inside of the structure in the region of the glass plates near the support pillars. The implications of these stresses are discussed. It is concluded that it is possible to design a pillar array for which the localised tensile stresses and overall thermal conductance have usefully small values.
The Nature of Pulsar Subpulse Drift
Authors: Kazbegi AZ , Machabeli GZ , Melikidze GI
Published: June 2013

A possible mechanism for the explanation of pulsar subpulse drift is suggested. In the region of the open magnetic field lines the existence of an electron-positron plasma penetrated by a primary particle beam is assumed. There is a possibility of excitation of large-scale drift waves propagating transversely to the magnetic field lines. These waves can affect the fulfilment of the radio-wave generation conditions. If the pulsar angular velocity is near to the frequency of the drift waves one should observe regular drift phenomena.
Kinetic Equation with Neutrino Oscillations in the Early Universe
Authors: Granek Henry , HJ McKellar Bruce
Published: June 2013

This paper considers the kinetic equation for interacting neutrino gas in the context of an expanding early universe. It is suggested that if neutrino oscillations are present and CP violations occur prior to the decoupling of the neutrino gas from the rest of the universe, then lepton number may not be conserved and, in principle, significant permanent neutrino chemical potentials may develop and survive until the present day. This would lead to the wen known effect that if the electron neutrino chemical potential is significantly non-zero, then the primordial abundances of the light elements are affected and differ from those of the standard model. Numerical computation is required to examine the parameter ranges leading to a significant non-zero electron neutrino chemical potential.
Characterisation of Semiconductors by Differential Reflectance Spectroscopy
Authors: Shwe C , Gal M
Published: June 2013

We have used differential reflectance (DR) spectroscopy, an optical modulation technique which does not require external modulation, to characterise bulk semiconductors and semiconductor microstructures. DR signals are the result of inhomogeneities on or below the semiconductor surface. They may be intrinsic, such as alloy fluctuations or layer thickness variations, or externally induced, such as ion implantation, hydrogenation, etc. The DR spectra are similar to spectra measured by other modulation techniques, exhibiting sharp derivative�like lineshapes at photon energies corresponding to the critical point transitions. The magnitude of the DR signal, its position and linewidth can all be used to identify and characterise fluctuations in semiconductor parameters, for example surface electric field, alloy composition, layer thicknesses, etc. It can also be used to monitor surface damage caused by different techniques, such as hydrogenation, reactive ion etching and ion implantation.
The MOST and Other Radio Telescopes
Authors: Robertson JG
Published: June 2013

The MOST performs rotational synthesis, in common with the Australia Telescope and other arrays overseas. However, the MOST's unique construction fits it into a complementary rather than a competitive niche, with its particular strength being rapid surveys of large areas of sky.
Dissociative Ionisation and Neutral Dissociation: CF4, a Case Study
Authors: Bonham RA , Bruce MR
Published: June 2013

New results for the total neutral dissociation cross section and an estimate of the gross cross section for the production of neutral fluorine by electron impact on CF4 have been obtained by combining previously reported results for the total dissociation cross section and the counting cross section for the total dissociative ionisation. This advancement was made possible by recently reported results for multication formation obtained from coincidence experiments. The estimate of the neutral fluorine production cross section is of the same order of magnitude as the total dissociation cross section itself, a similarity which may explain why CF4 is such an effective etching gas. The available cross section data for electron impact energies between 5 and 200 e V are reviewed.
Low-energy Electron Scattering from Polyatomic Molecules: The Role of Electron Correlation
Authors: William McCurdy C
Published: June 2013

Until recently the principal barrier to the accurate theoretical description of electronic collisions with polyatomic molecules was the problem of scattering by a nonlocal potential which is arbitrarily asymmetric. The last five or six years have seen the development of numerical techniques capable of solving the potential scattering problem, and the first applications of methods for treating many-body aspects of collisions of electrons with polyatomic molecules are beginning to appear in the literature. We describe the complex Kohn method and the use, in scattering calculations, of methods for treating electronic correlation which are standard in bound-state quantum chemistry. As examples of the application of these ideas we present the results of calculations on electron scattering from CH4, SiH4 and C2H6. All of these molecules exhibit Ramsauer-Townsend minima at low impact energies which are entirely correlation effects.
Some Recent Studies of Electron Swarms in Gases
Authors: Tagashira H
Published: June 2013

Some recent studies of electron swarms in gases under the action of an electric field are introduced. The studies include a new type of continuity equation for electrons having a form in which the partial derivative of the electron density with respect to position and to time are interchanged, a method to deduce the time-of-flight and arrival-time-spectrum swarm parameters based on a Fourier-transformed Boltzmann equation, an examination of the correspondence between experimental and theoretical electron drift velocities, and an automatic technique to deduce the electron-gas molecule collision cross section from electron drift velocity data. We also briefly introduce a method for the deduction of electron collision cross sections with gas molecules having vibrational excitation cross sections greater than the elastic momentum transfer cross section by using a gas mixture technique, an integral type of method for solution of the Boltzmann equation with salient numerical stability, a quantitative analysis of the effect of Penning ionisation, and the behaviour of electron swarms under radio frequency electric fields.
Optical Studies of Pre-breakdown Electron Avalanches
Authors: Blevin HA , Fletcher J
Published: June 2013

This paper reviews the work carried out at Flinders University over a number of years in relation to the light output from pre-breakdown Townsend discharges and isolated electron swarms. This 'luminous flux' technique has important advantages over conventional current measurements since regions remote from electrode boundaries can be studied yielding values of electron drift velocity, diffusion coefficients and ionisation/attachment rates from a single experiment. For the first time the internal structure of a single swarm has been studied by observing the light from different excited states. From these results it is clear that, in many cases, the diffusion equation does not give an adequate description of the spatial and temporal development of electron concentration, and higher order transport parameters are required in the analysis of experiments.
Star Formation in the Galaxy
Authors: J McGregor Peter
Published: June 2013

Star formation in the Galaxy occurs on different spatial scales from single star formation events in Bok Globules to the formation of OB associations and star clusters. We review recent observations of Bok Globules and relate them to the dense NH3 cores observed in dark clouds. Recent work on the Chamaeleon I dark cloud supports quasi-static subcritical collapse models for low mass star formation. This cloud is a typical region of low mass star formation similar to the Taurus-Auriga clouds; star formation has continued in the cloud for ",107 yr, the most massive embedded stars have masses of "'2M0, and the cloud appears to be magnetically supported in its long dimension.
Magnetic Susceptibility of V, Cr, Mn and Mo and Magnetism in Cr and Mn
Authors: Zhao Yuzhi , Fry JL
Published: June 2013

A tight-binding formulation has been used to compute the many-body enhanced magnetic susceptibility X(q) of transition metals around Cr in the periodic table. The pole structure of X(q) indicates paramagnetism for V and Mo, antiferromagnetism for Cr and I'Mn, and ferromagnetism for 8Mn at T = 0 K.
Anisotropic Dispersion of a Charged Particle Swarm in a Turbulent Gas in an Electrostatic Field
Authors: Robson RE
Published: June 2013

This paper generalises an earlier result of Saffman (1960) to account for cross effects between turbulent and molecular diffusion for charged particle swarms in a gas in the presence of an electrostatic field. It is shown that turbulence enhances the anisotropic character of diffusion. The desirability of using a full kinetic theory analysis as against a limited hydrodynamic description of the swarm is discussed, and one possible tractable approach pointed out.
Collisionless Damping of Fast and Ion?Cyclotron Surface Waves
Authors: Rowe GW
Published: June 2013

A recently developed general kinetic theory of surface waves is used to calculate the collisionless damping of low frequency fast and ion-cyclotron surface waves on a magnetised plasma-vacuum interface. In particular, the possibility of Cherenkov (Landau and transit-time magnetic) absorption by electrons is accounted for, assuming a bi-Maxwellian distribution of electrons in velocity space. It is shown that in general the surface waves are damped via mode conversion to a short-wavelength mode, such as the kinetic Alfven wave, which is subsequently Landau absorbed within the plasma. For high temperatures this short-wavelength mode can also be radiated into the plasma without being completely absorbed. It is also shown that the related ion-sound surface wave mode and instability identified by Alexandrov et al. (1984) are unphysical, and are the result of neglecting the gas pressure in the first-order magnetic field boundary condition.
Characterisation of III?V Multilayers Grown by Low-pressure Metal Organic Vapour-phase Epitaxy
Authors: Jagadish C , Clark A , Li G , Larson CA , Hauser N , Petravic M , Thompson TD , Halstead T , Williams JS
Published: June 2013

Undoped and doped layers of gallium arsenide and aluminium gallium arsenide have been grown on gallium arsenide by low-pressure metal organic vapour-phase epitaxy (MOVPE). Delta doping and growth on silicon substrates have also been attempted. Of particular interest in the present study has been the influence of growth parameters, such as growth temperature, group III mole fraction and dopant flow, on the electrical and physical properties of gallium arsenide layers. An increase in growth temperature leads to increased doping efficiency in the case of silicon, whereas the opposite is true in the case of zinc. Deep level transient spectroscopy (DTLS) studies on undoped GaAs layers showed two levels, the expected EL2 level and a carbon-related level. The determination of optimum growth conditions has allowed good quality GaAs and AlGaAs epitaxial layers to be produced for a range of applications.`
Charge Fluctuations in High-Electron-Mobility Transistors: A Review
Authors: Green F
Published: June 2013

The physics of high-electron-mobility transistors (HEMTs) plays a central role in contemporary design for millimetre-wave communications. HEMTs are the early fruits in a harvest of increasingly radical devices whose structural features are measured in nanometres. The operating principles of these devices are richly varied, and almost always far from classical. One of the tasks for device physics is to understand fluctuation phenomena, .or noise: the control of charge fluctuations is basic to high performance, yet the description of these processes remains incomplete if not obscure. This paper reviews some aspects of charge-transport noise that affect HEMT operation.
Covariant Formulation of the Ponderomotive Force
Authors: Luo Qinghuan , Melrose DB
Published: June 2013

A covariant and gauge-invariant theory of the ponderomotive force is developed for both unmagnetised and magnetised collisionless plasmas. The full expression for the force density exerted on the particle background by the waves (or the ponderomotive force in the general sense) is derived for both the unmagnetised and the magnetised cases. In the magnetised case, the 4-dimensional metric is projected into 'parallel' and 'perpendicular' components. The force density on the particle background then has a similar form to that for the unmagnetised case. The usual ponderomotive force is identified in the same way as in the unmagnetised case and has an equivalent form to that in the unmagnetised case when written in terms of the linear response tensor.
Quasi-particle Interference Effect in the Coulomb Blockade Problem
Authors: Hu CD , Mahanty J
Published: June 2013

The Coulomb energy in a tunnel junction of very small capacitance, in which there are two or more kinds of quasi-particles, will involve coupling between pairs of quasi-particle species. The variation in the number of one of them will affect the motion of the others. This should be detectable in a current-biased experimental setup. Taking Josephson and single-electron tunnelling as an example, we calculate the Fourier coefficients of the voltage across the junction, which is a periodic function of time. We show that the interference effect is significant in that the frequency dependence of the Fourier coefficients is completely different from that associated with tunnelling of a single species.
Low-temperature Thermal Expansion Anomalies in Indium and Its Solid Solution Alloys with Thallium
Authors: Liu M , Finlayson TR , Smith TF
Published: June 2013

Low-temperature thermal expansion measurements have been made for fct, solid solution indium-thallium single-crystal alloys containing 6, 19, 24 and 29 at.% Tl. The expansion coefficients along the a and c axes for the 6, 19 and 24% alloys follow the same anomalous variations with temperature below about 15 K as for those of pure indium, with no change in magnitude. This contrasts with an increased magnitude for the anomalies previously reported for an In26�5at.%TI alloy and reported here for the a-axis expansion for In29at.%Tl. These observations are discussed in terms of the Fermi surface topology for indium and their implications for the fcc to fct transformation in In-TI alloys being electronically driven.
Statistical Symmetries in Physics
Authors: Green HS
Published: June 2013

Every law of physics is invariant under some group of transformations and is therefore the expression of some type of symmetry. Symmetries are classified as geometrical, dynamical or statistical. At the most fundamental level, statistical symmetries are expressed in the field theories of the elementary particles. This paper traces some of the developments from the discovery of Bose statistics, one of the two fundamental symmetries of physics. A series of generalizations of Bose statistics is described. A supersymmetric generalization accommodates fermions as well as bosons, and further generalizations, including parastatistics, modular statistics and graded statistics, accommodate particles with properties such as 'colour'. A factorization of elements of ggl (nb' n f) can be used to define truncated boson operators. A general construction is given for q-deformed boson operators, and explicit constructions of the same type are given for various 'deformed' algebras; these include a rather simple Q-deformed variety as well as the well known q-deformed variety. A summary is given of some of the applications and potential applications.
Wild, Woolley and Savage ? or how John Bolton and I went hunting for Quasars and QSOs
Authors: Savage Ann
Published: June 2013

This paper is about how I met John Bolton and includes some highlights of the four years I took compiling my Ph.D. at the Parkes Observatory. It is strongly linked to the discovery of quasars (quasi-stellar radio sources) and QSOs (quasi-stellar objects, not necessarily radio sources)-John being dedicated to discovering quasars and I to discovering QSOs. I hope my perception of John Bolton as a person comes through as it seems I was fortunate in meeting him at a time when, according to some, he had mellowed!
Compact Radio Sources, Quasars and Active Galactic Nuclei
Authors: Kellermann KI
Published: June 2013

This paper reviews John G. Bolton's contributions to our understanding of compact radio sources associated with quasars and active galactic nuclei (AGNs), and his work leading to the discovery of quasars. Particular attention is given to the interpretation of the observed properties of quasars and AGNs within the framework of unified models which interpret the wide variety of observed properties as being the result of orientation rather than of any intrinsic differences.
Partial Wave Expansion of Three-particle Continuum. States in Hyperspherical Coordinates: Application to Ionisation Problems
Authors: Das JN
Published: June 2013

A partial wave expansion of three-particle continuum states has been developed using hyperspherical coordinates. An approximate three-particle continuum state appears which may be useful in electron-hydrogen atom ionisation studies. Further improvement in the result is also possible. The analysis may be easily extended for application to other three-body ionisation problems.
Schwinger Variational Calculation for Ionisation of Hydrogen Atoms by Electrons
Authors: Das JN , Dey A , Chakrabarti K
Published: June 2013

The Schwinger variational principle has been used to calculate the triple differential cross section for ionisation of hydrogen atoms by electrons at intermediate and high energies for Ehrhardt-type asymmetric geometry. The results are somewhat better in the recoil peak regions compared with those of the second Born and other similarly successful calcula
Effect of Electron Inertia on Double Layers in a Relativistic Hot Plasma
Authors: Roy Chowdhury K , Paul SN , Roy Chowdhury A
Published: June 2013

The ion-acoustic double layer in a relativistic hot plasma is studied by considering the effect of electron inertia. The critical region is analysed with the help of a combination of the KdV and mKdV equations obtained via a reductive perturbation technique. The profiles of the double layer are explicitly obtained for various values of the plasma parameters and of the electron-ion mass ratio.
Evidence for Top Quark Production in pp Collisions at vs = 1.8 TeV
Authors: L Tipton for the CDF Collaboration Paul
Published: June 2013

We summarise a search for the top quark with the Collider Detector at Fermilab (CDF) in a sample of pp collisions at Vs = 1� 8 Te V with an integrated luminosity of 19�3 pb ~ 1. We find 12 events consistent with either two W bosons, or a W boson and at least one b jet. Both of these are signatures for tt events. The probability that the measured yield is consistent with the background is 0�26%. Though the statistics are too limited to establish firmly the existence of the top quark, a natural interpretation of the excess is that it is due to tt production. Under this assumption, constrained fits to individual events yield a top quark mass of 174 � lO:::g GeV / c2? The tt production cross section is measured to be 13.9:::~:~ pb.
Photoelectron Spectroscopy of Solids Using Synchrotron Radiation
Authors: Leckey Robert , Riley John
Published: June 2013

A brief review of the technique of angle-resolved photoelectron spectroscopy as used in conjunction with synchrotron radiation is given. Examples of the use of the technique which emphasise the collection of full-hemisphere data are presented, covering the determination of Fermi surface topology and photoelectron diffraction/holography. An example of an investigation of quantum size effects and of the use of magnetic circular dichroism to explore the interaction of spin-orbit and exchange effects in iron is also provided.
The Prospects for Very High Energy Gamma Ray Astronomy
Authors: Kifune T
Published: June 2013

Very-high-energy (VHE) gamma rays, with energies .<: 1 TeV = 1012 eV, are observed with ground-based telescopes using the atmospheric Cerenkov technique. This field of astronomy has recently experienced its coming of age, opening a new observational window on the universe after efforts spanning almost 30 years. Recent advances in this field have been aided by the results from satellite detectors with high-energy (HE) gamma ray 'eyes'. Satellite detectors are sensitive to HE gamma rays, up to energies of about 10 GeV = 1010 eV. In this paper, VHE gamma ray astronomy is reviewed, and the 3�8 m diameter telescope of the Japanese-Australian CANGAROO project is used to illustrate the detection techniques. As VHE gamma ray astronomy is closely related to observations in the HE region, results from recent satellite experiments are also discussed.
Introduction
Authors: Cooper and Toshiaki Makabe Ron
Published: June 2013

In recent scientific history Australia and Japan have been especially active and gained international acceptance as centres of excellence in the areas of gaseous electronics. In this area of study, the identity and behaviour of all species-both charged and neutral, molecular and fragmented-in ionised gases are studied and theoretically modelled.
Drift Velocity and Longitudinal Diffusion Coefficient of Electrons in CO2?Ar Mixtures and Electron Collision Cross Sections for CO2 Molecules
Authors: Nakamura Y
Published: June 2013

The drift velocity and longitudinal diffusion coefficient of electrons in 0�2503% and 1� 97% C02-Ar mixtures were measured for 0�03 ~ E/N ~ 20 Td. The measured electron swarm parameters in the mixtures were used to derive a set of consistent vibrational excitation cross sections for the C02 molecule. Analysis of electron swarms in pure C02 using the present vibrational excitation cross sections was also carried out in order to determine a new momentum transfer cross section for the C02 molecule.
Helicon Wave Measurements in an Inductively Coupled Magnetoplasma
Authors: Nakamura Keiji , Suzuki Keiji , Sugai Hideo
Published: June 2013

Small-amplitude test waves at 30-100 MHz are externally excited in an inductive rf plasma for a magnetic field of rv100 G, to obtain a full dispersion relation for helicon waves. Measured wavelengths agree well with theoretical ones, not only for the test waves but also for largeamplitude principal waves at the discharge frequency of 13�56 MHz. Absolute measurements of the radial magnetic field B; of the large-amplitude helicon wave are carried out, and the r, q and z components of the wave electric field are estimated to be E; rv Eo rv 8 V cm-1 and Ez rv 0�7Vcm-1 at an rf power of 800 W.
Transport Analysis of RF Drift-velocity Filter Employing Crossed DC and AC Electric Fields for Ion Swarm Experiments
Authors: Iinuma K , Takebe M
Published: June 2013

The operational characteristics of the RF drift-velocity filter developed recently by us to separate a mixture of gaseous ions are examined theoretically. The solutions of the appropriate transport equations provide an analytical formula for the transmission efficiency of the filter in terms of the mobility and diffusion coefficient of the ions, the electric field strength, the RF frequency and the filter dimension. Using the experimental transport data for Li+ /Xe and Cs+ /Xe, the formula was tested and we find that it adequately accounts for the degree of ion separation achieved by the filter at high gas pressures. The variation of the profiles of the arrival time spectra for Li+, Na+ and Cs+ ions in C02, obtained by our drift-tube experiments, also supports this analysis.
Reactive Plasma Species in the Modification of Wool Fibre
Authors: Dai XJ , Hamberger SM , Bean RA
Published: June 2013

Physical and chemical changes to the surface properties of wool fibre caused by exposure to RF generated plasma have been studied. Comparison is made between the changes for a wide range of plasma conditions and of the experimentally measured concentrations of the relevant neutral and charged particle species to elucidate those principally responsible and the likely mechanism. Results show that the measured increase in surface energy (from hydrophobic to hydrophilic) is well correlated with the integrated flux to the fibre of atomic oxygen, regardless of its origin. Charged particles appear to have little effect beyond sputtering, while the role of metastable excited oxygen molecules seems to be not statistically significant. Changes in surface chemistry shown by XPS are consistent with direct interaction of reactive � on the C-C and C-H bonds of the lipid layer which forms the outer (",,3 nm thick) layer of the natural fibre. Similar but weaker effects sometimes seen with discharges in argon appear to be due to the presence of oxygen as an impurity.
The University of Western Australia?s Resonant-bar Gravitational Wave Experiment
Authors: Tobar ME , Blair DG , Ivanov EN , van Kann F , Linthorne NP , Turner PJ , Heng IS
Published: June 2013

The cryogenic resonant-mass gravitational radiation antenna at the University of Western Australia (UWA) has obtained a noise temperature of <2 mK using a zero order predictor filter. This corresponds to aIms burst strain sensitivity of 7x 10-19 . The antenna has been in continuous operation since August 1993. The antenna operates at about 5 K and consists of a 1� 5 tonne niobium bar with a 710 Hz fundamental frequency, and a closely tuned secondary mass of 0�45 kg effective mass. The vibrational state of the secondary mass is continuously monitored by a 9�5 GHz superconducting parametric transducer. This paper presents the current design and operation of the detector. From a two-mode model we show how we calibrate, characterise and theoretically determine the sensitivity of our detector. Experimental results confirm the theory.
Introduction
Authors: J Buckman Stephen , Weigold Erich
Published: June 2013

The Advanced Workshop on Atomic and Molecular Physics was held at the Research School of Physical Sciences and Engineering, Australian National University between February 13-15, 1995. The Workshop was a bilateral meeting involving physicists and chemists from Australia and the United States and the main goals were to bring together research workers in the field of low energy atomic and chemical physics to review recent advances and to chart possible directions for the future. The Workshop attracted 75 registrants. Of these, 20 eminent speakers in diverse areas of atomic and molecular physics were supported directly by grants from the Department of Industry, Science and Technology (Australia) and the National Science Foundation (USA). The remaining 55 attendees comprised 30 staff and, most importantly, 25 postgraduate students from Australian institutions.
Spin-resolved Alignment and Orientation Effects in Atomic Collisions
Authors: Bartschat Klaus , Andersen Nils
Published: June 2013

The density matrix parametrisation of collisionally excited atomic ensembles is generalised to account for projectile and target spin polarisations. The density matrix elements, containing spin-resolved alignment and orientation parameters, can be determined by measurements of the 'generalised Stokes parameters' introduced by Andersen and Bartschat (1994) to describe scattered-projectile-polarised-photon coincidence experiments. Focusing on electron impact excitation of light alkali-type targets and mercury, the present experimental status of such experiments is reviewed, in particular with regard to the 'perfect scattering experiment' whereby all independent scattering amplitudes are determined.
Recent Applications of (e, 2e) Techniques
Authors: Brunger MJ
Published: June 2013

The flexibility of the (e, 2e) technique in obtaining information on both structure and collision dynamics is demonstrated. An example of the structure information that can be obtained is illustrated by electron momentum spectroscopy studies on krypton, while the role of post-collision effects and correlations is explored by measurements in the autoionising region of helium.
Monte Carlo Calculations of Effective Surface Tension for Small Clusters
Authors: N Hale Barbara
Published: June 2013

In this study we have calculated configurational Helmholtz free energy differences between n and n – 1 molecule water clusters and nand n – 1 atom argon clusters using classical effective atom-atom pair potentials and the Bennett–Metropolis Monte Carlo technique. When plotted versus n–1/ 3 the slope of the free energy differences yields an effective surface tension, σ. It is found that these slopes display a universal (material independent) property related to the excess surface entropy / κ per molecule (or atom), Ω. For most materials (in the bulk liquid state) the latter quantity is about 2. The results indicate that clusters as small as n = 10 display bulk surface free energy properties. The temperature dependence of the effective surface tension for the model water clusters is also investigated and is consistent with a simple scaled form, σ / κTρ2/3liquid ≈ Ω(Tc /T – 1), where Tc = 647 K and Ω = 1�9.
Methoxy and Methoxide Adducts of Fullerene-60: Semiempirical Theoretical Studies
Authors: Barrie Peel J
Published: June 2013

Semi empirical molecular orbital calculations utilising the AM1 approximation with the MOPAC program have been used to suggest the likely stable isomeric structures of the smaller methoxylated adducts of C60, namely the anions C60(OMe)-n, n = 1,3,5,7, and the neutral species C60(OMe)n, n = 2,4,6. While the OMe species is expected to behave similarly to the F atom in respect of its electronegativity and electrophilicity, its greater size and asymmetric geometry influences the role of non-bonded interactions in determining the favoured configurations and relative chemical stabilities of the respective isomers of each structure. The 'string' model which describes the localised addition pattern observed in the case of the bromine adducts, C60Br2n, for n values up to 12, is also appropriate in describing the stable OMe and OMe- adducts of C60. The five-fold symmetric C60(OMe)-5 anion is of particular interest as it is revealed as the most stable species, in agreement with its observation as the most abundant species occurring in electrospray mass spectra. This suggests that metal salts of the general type M+C60L-5 may be isolable under appropriate experimental conditions.
Direct Observation of EnergyMomentum Densities in Solids
Authors: Weigold E , Cai YQ , Canney SA , Kheifets AS , McCarthy IE , Storer P , Vos M
Published: June 2013

Electron momentum spectroscopy (EMS), based on kinematically complete observations of high energy electron impact ionisation events, directly observes energymomentum dispersion laws and densities of electrons in solids. The valence electronic structure in the near surface region, up to a depth of about 20 Å is probed for thin free-standing films (about 100 Å) by the multiparameter EMS spectrometer at Flinders University. The principles of the measurement are described and its application to the determination of energymomentum densities in a range of amorphous, polycrystalline and crystalline materials is discussed.
Nonlinear Effects in Single-photon Resonant Excitation of Atomic Hydrogen
Authors: Unnikrishnan K
Published: June 2013

The first nonperturbative calculation of the amplitude for the excitation of a discrete atomic state by a classical electrornagnetic field is described. Specifically, the excitation amplitude for the H(ls) → H(2p) transition involving the net absorption of only one photon is shown to exhibit a nonlinear dependence on the field amplitude beyond an intensity I ≈ 1013 W cm-2 In this region, the rate of change of the transition amplitude decreases with increasing field strength, finally becoming negative after I ≈ 4 X 1014 W cm-2. Degeneracy of the excited state is shown to be largely responsible for the early onset of such behaviour, thereby picking out atomic hydrogen as the most suitable target for experimental observations.
Gauge Variance of Diamagnetic and Paramagnetic Moments
Authors: Stewart AM
Published: June 2013

A simple expression is obtained for the origin dependent change of the gauge variant paramagnetic and diamagnetic components of the electronic orbital magnetic moment. The sum of the two is gauge invariant, as is the total magnetic susceptibility.
Quantum Measurements in Atom Optics
Authors: Walls DF
Published: June 2013

We review recent progress in atom optics. We describe new quantum measurements based on the entanglement of quantum states of a light field with atomic external degrees of freedom. Examples include the quantum non-demolition measurement of the photon number in a cavity and the measurement of atomic position.