bluuebunny/crossref_metadata_2025 huggingface dataset:
New Developments in Optical Microscopy for Biological Applications
Authors: Dixon Andrew
Published: June 2013

In the past ten years a quiet revolution has been taking place in optical
microscopy. So quiet indeed that if one has not been working in life sciences
research one may have seen little or no evidence of it. Yet what has been
going on is an excellent example of how developments in physical
instrumentation drive research and research in turn drives further
developments in instrumentation. In this paper I will briefly review these
developments in optical microscopy and, in particular, show how processes
originally proposed 65 years ago as esoteric theoretical solutions to
Dirac’s equation are now used in practice for some of the most
adventurous biological microscopy yet attempted.
High-field Study of Layered Manganites R1/2Sr3/2MnO4 (R = La and Nd)
Authors: Tokunaga M. , Miura N. , Moritomo Y.
Published: June 2013

We have studied the effects of a magnetic field on the magnetism and transport
properties of the layered manganites
R1/2Sr3/2MnO4
(R = La and Nd) in pulsed magnetic fields up to
40 T. The R = La crystal shows metamagnetic-like
transitions above 30 T, concomitantly with a colossal magnetoresistance (CMR)
effect as large as [ρ(0) - ρ(H)]/ρ(H) >
103 with a field of µοH = 38 T at low
temperatures. These transitions can be ascribed to the field-induced melting
of the real-space ordering of the
eg electrons (charge ordering).
For the R = Nd crystal, a magnetic field along
the c-axis enhances the two-dimensionality in the
conductivity. Moreover, we observed metamagnetic-like transitions accompanied
by the CMR effects at low temperatures, in spite of the absence of charge
ordering.
Nonlinear Dynamics of the Dust Grain Charge and Dust Acoustic Waves in a Plasma with an Ion Beam
Authors: Nejoh Y. N.
Published: June 2013

The temporal evolution of the dust grain charge is investigated for the first
time in a dusty plasma with an ion beam. The grain charge attains to the
stationary state after the fluctuation of short time. The dust charge
increases as the ion beam temperature and the plasma ion density increase, but
decreases as the beam density increases. The speed of the wave increases as
the ion density and temperature increase, whereas it decreases as the dust
charge increases. The variable dust mass-to-charge and ion-to-electron density
ratios govern the existence of dust acoustic waves. The findings of this
investigation may be useful in understanding laboratory plasma phenomena.
Vapour - Liquid Equilibrium Properties for Two- and Three-dimensional Lennard-Jones Fluids from Equations of State
Authors: Mulero A. , Cuadros F. , Faúndez C. A.
Published: June 2013

Vapour–liquid equilibrium properties for both three- and two-dimensional
Lennard-Jones fluids were obtained using simple cubic-in-density equations of
state proposed by the authors. Results were compared with those obtained by
other workers from computer simulations and also with results given by other
more complex semi-theoretical or semi-empirical equations of state. In the
three-dimensional case good agreement is found for all properties and all
temperatures. In the two-dimensional case only the coexistence densities were
compared, producing good agreement for low temperatures only. The present work
is the first to give numerical data for the vapour–liquid equilibrium
properties of Lennard-Jones fluids calculated from equations of state.
A Millisecond X-ray Reflectometer
Authors: White John W. , Garrett Richard F. , Brown Anthony S. , King David J. , Dowling Trevor L.
Published: June 2013

Many important processes occur at surfaces and interfaces on timescales
ranging from milliseconds up to hours. The advent of third generation
synchrotrons provides X-ray fluxes sufficiently high that it is now
conceivable that these processes can be studied with millisecond time
resolution using X-ray reflectometry. Several configurations for an X-ray
reflectometer designed to measure X-ray reflectivity profiles with this time
resolution are examined. The feasibility of each configuration in terms of
information retrieval from reflectivity data is explored by application of
modelling techniques to simulated ‘experimental’ data.
Properties of the Inelastic Form Factors of the Nucleus
Authors: Koo WK , Tassie LJ
Published: June 2013

Based on an inversion formula for the energy-weighted sum rules, a study is made of the properties of the inelastic form factors of the nucleus. The inversion formula is derived by using a simple representation of the identity operator for a restricted set of non-orthogonal states and it is applicable to both isoscalar and isovector transitions. As a result, it is shown that the longitudinal form factor for a particular multipolarity cannot be explicitly factorized into a product of a function of momentum transfer and a function of excitation energy over the entire range of momentum transfer. Further, the ambiguity arising out of the use of the hydrodynamical model to assign spins of giant resonances is illustrated, taking the isovector electric dipole form factor as an example.
Isospin Mixing in Light Nuclei
Authors: Barker FC
Published: June 2013

Isospin mixing matrix elements are calculated for several pairs of mixed T = 0 and 1 states in aBe, 12C and 160, using an extension of the method of Dalton and Robson (1966). This includes contributions due to differences between neutron and proton wavefunctions produced in the asymptotic region by the Coulomb force, as well as the internal Coulomb contribution. These cases provide no evidence for a charge-dependent nuclear interaction other than the Coulomb interaction.
Threshold Effects in Proton-induced Reactions on Copper
Authors: Switkowski ZE , Heggie JCP , Mann FM
Published: June 2013

A study has been made of proton-induced reactions on the two copper isotopes 65CU and 63CU for bombarding energies in the range 1�2-4�6 MeV. This energy range includes the (p,n) thresholds for 65CU and 63CU, which occur at 2�17MeV and 4�21 MeV respectively. Excitation functions for (p, y) reactions were obtained by observing discrete y-ray transitions between low-lying states of the compound nuclei. Data were also obtained for the charged-particle reactions 65Cu(p,lXo)62Ni and 63CU(p, lXo.,)6�Ni. As the respective (p, n) thresholds are crossed, the yields of proton-induced reactions on 65CU fall by a factor of about 5 while the excitation functions of proton-induced reactions on 63CU reveal no evidence of a significant threshold effect. These data are ompared with Hauser-Feshbach statistical model calculations. The structure in the 65CU+p reaction yield is interpreted in terms of Wigner cusps.
18O(p, ?)19F and 18O(p, p'g)18O Reactions below 3·50 MeV
Authors: Din GU
Published: June 2013

The )I-ray decay schemes of resonance levels from the 180(p, )I)19F reaction in the energy range Ep = 630-2260 ke V and the angular distributions of the 1 �98 Me V )I rays from inelastically scattered protons from 180 in the energy range Ep = 3�00-3� 50 MeV have been studied to obtain additional information on the properties of the resonant and bound levels of 19F. Single )I-ray spectra have been measured using high resolution 40 and 120 cm3 Ge(Li) detectors for the 10 resonances at Ep = 630, 850, 1169, 1400, 1620, 1770, 1933,2010,2175 and 2260 keY.
Estimation of the Equilibrium Properties of the Simple AB Alloy
Authors: Johnson CHJ
Published: June 2013

Simulation estimates are presented for the equilibrium values of energy, long-range order and particle concentration as functions of temperature and chemical potential for the AB aIloy set on a simple square lattice. The simulation was based on a simple Markov process with transitions defined in terms of particle exchange between nearest-neighbour lattice sites. An ensemble mode of relaxation, employing an ensemble of five 32 x 32-particle samples from the aIloy, was used in order to reduce the level of the fluctuations. The usual periodic boundary conditions were replaced by probability boundary conditions where the states of the external lattice site were estimated using probability distribution functions whose lower moments were equal to the running moments of the sample.
Commutation Rules for Generalized Pauli Spin Matrices
Authors: Jeffery EA
Published: June 2013

The algebra is developed for matrices involved in 2(2j+ I)-component arbitrary spin equations. These matrices can act as generators for the unitary group, and are shown to deserve the name 'generalized Pauli spin matrices'. Their commutation and anticommutation rules are derived from those for the ordinary Pauli spin matrices by a method termed mixed induced multiplication.
Determination of Maximum Safe Bombarding Energies and B(E3) Values in Reorientation Experiments with 204Pb, 206Pb and 208Pb
Authors: Spear RH , Zabel TH , Baxter AM , Fewell MP , Hinds S , Joye AMR , Kean DC
Published: June 2013

Data are presented which display the onset of Coulomb-nuclear interference in the inelastic scattering of 4He, 12C and 160 projectiles from 204Pb and 206Pb. These results have been used to determine maximum safe bombarding energies in a recent reorientation effect determination of the quadrupole moments of the first 2+ states in these nuclei. Similar data are also presented for the excitation by projectiles of the first 3 - states in 204Pb, 206Pb and 208Pb. The results are used to determine B(E3; 0+-.3-) values for the first 3- states of 204Pb and 206Pb; these are found to be remarkably similar to each other and to the corresponding value for the first 3 - state in 208Pb.
Vibronic Effects in Mossbauer Spectra: The 57Fe Quadrupole Splitting in FeCO3
Authors: Price DC
Published: June 2013

The methods developed by Orbach and coworkers for calculating spin-lattice relaxation rates have been generalized to enable calculation of the effects of vibronic admixture between low-lying electronic states on observables, such as the Mossbauer quadrupole splitting, associated with magnetic ions in crystals. Emphasis is placed on the need to take proper account of the symmetry properties of the phonons until a late stage in the calculation. Application is made to the temperature dependence of the 57Fe quadrupole splitting in FeC03 , and it is concluded that, in general, vibronic coupling effects must be considered before static splitting parameters are extracted from experimental data relating to the temperature-dependent populations of electronic levels. The superposition model of the crystal field is employed to estimate the vibronic coupling parameters.
Extensive Air Showers and Radio Frequency Electromagnetic Fields
Authors: Sivaprasad K
Published: June 2013

An estimate is made of the electric field expected from the ionization electrons produced by an extensive air shower moving in the geoelectric field for frequencies from 10 kHz to 10 MHz. The calculations are for a geoelectric production mechanism, and they invoke quite reasonable assumptions regarding the shower development. The calculated fields are found to be comparable with those produced by the geomagnetic mechanism, and fall short of the high values observed in this frequency range. Higher fields cannot be obtained from the present shower mechanism under normal weather conditions, but would require exceptionally large values for the geoelectric field (1 MVm-1) or a model for electron diffusion that is radically different from that assumed here.
Laboratory Modelling of Neutron Star Magnetospheres
Authors: Eremin BG , Zheleznyakov VV , Kostrov AV , Z. Slutsker Ya , Suvorov EV
Published: June 2013

The problem of modelling a rotating neutron star magnetosphere is discussed. Attention is drawn to the possibility of qualitative modelling of this cosmic object without conforming to the similarity laws. Two models, one simulating an aligned magnetic rotator and the other an oblique rotator, are suggested. Preliminary results from such modelling of pulsar magnetospheres in the oblique rotator case are reported.
Galactic Supernova Remnants: Radio Evolution and Population Characteristics
Authors: Caswell JL , Lerche I
Published: June 2013

Shell SNRs show a systematic gradient of radio surface brightness normal to the galactic plane, and a measured scale height for this effect has been obtained. The progenitor distribution and birth rate are significantly modified when allowance is made for this effect. The galactic height dependence of radio surface brightness satisfactorily accounts for the otherwise anomalous highlatitude SNR AD 1006. It also provides a crucial clue to the origin of the radio emission, suggesting that the interstellar magnetic field is dominant over internally generated fields in shell SNRs. Recently we have independently reached the same conclusion from a consideration of the cumulative number count of shell SNRs.
On the Structure of the Crab Nebula
Authors: Matveyenko LI , Kostenko VI
Published: June 2013

Utilizing a large number of published observations, we investigate the detailed structure of the Crab Nebula over a range of wavelengths from 3�5 mm to 75 em, and identify many different features. The spectra of some of these features are followed to longer wavelengths, extending to nearly 10 m. Physical conditions within the features are discussed.
Comparison between the Boltzmann and Monte Carlo Simulation Methods for the Determination of Electron Swarm Transport Coefficients in Molecular Hydrogen
Authors: D Reid Ivan , R Hunter Scott
Published: June 2013

The transport properties of an electron swarm drifting and diffusing in hydrogen as determined from a numerical solution of Boltzmann's equation are compared with those derived previously from a Monte Carlo simulation. The same set of cross sections has been used with each method to calculate transport coefficients in the range 0�5 .;;; EIN.;;; 200 Td. The comparison shows that the Boltzmann analysis is valid in this case whenever ionization is not significant.
Comment on Recent Results for 40Ca Giant Resonances obtained from the 40Ca(3He, 3He')40Ca ?36 Ar +a Reaction
Authors: Branford D
Published: June 2013

Yamagata et at. (1978) have recently made measurements on 40Ca giant resonance states using the 3He inelastic scattering reaction. It is shown here that the 3He spectrum obtained in coincidence with 0( particles leading to the 36 Ar ground state is similar in shape to the previously reported 36 Ar(O(, l'o)40Ca giant dipole resonance excitation function. The assignments of JX = 0+ and 3- (tentative) made to the 14�2 and 16�7 MeV states of 40Ca respectively are reconsidered. It is concluded that the (3He, 3He') data could be explained by assuming that the reaction proceeds through JX = 1 - giant dipole states.
Existence and Stability of Circular Orbits in a Schwarzschild Field with Nonvanishing Cosmological Constant
Authors: Howes RJ
Published: June 2013

The Schwarzschild metric with A > 0 allows circular orbits only within the annular region 3m < ro < (3m/A)-t. For m < tA --t this region includes a narrower annular zone, throughout which circular orbits are stable but outside of which they are unstable.
The HI Column Density as a Function of Position in the Southern Sky
Authors: Heiles C , Cleary MN
Published: June 2013

HI column densities for the LSR velocity ranges -50 to +50kms-1 and -100 to + 100 km S -1 are given in tabular and photographic forms for ~ .,. - 30� and I b I ~ 10�
An Analysis of the ?-ray Decay of Weak s Resonances in 40Ca
Authors: Knat'ko VA , Martsynkevich BA , Rudak EA
Published: June 2013

The structure of the negative-parity low-lying levels in 41Ca is calculated on the basis of a core-nucleon model. Good agreement is obtained between the calculated and experimental level characteristics. The resulting p-level wavefunctions are used to analyse the mechanism of the )I-ray decay of the weak s resonances in 40Ca at 20�4 and 42�1 keY.
The Nucleon Ground State
Authors: Rose EK , Cook JL , Clayton E
Published: June 2013

From the parameters obtained in a previous paper for the Pll pion-nucleon state, the ground state potential is determined and the meson probability density is calculated. The results hold for the simplest form of the overlap matrix and are phase-equivalent to an infinite set of nonlocal potentials.
Helium 23S Densities and Excitation Mechanisms in a Hollow Cathode He-Cd+ Laser
Authors: McIntosh AI , Grace JR
Published: June 2013

Helium singlet and triplet metastable number densities have been measured in the active region of a hollow cathode He-Cd + laser. The results are shown to be consistent with measurements of the electron density and energy distribution functions obtained in other experiments. The excitation mechanisms for the 441 �6 nm Cd + laser transi tion have been investigated by comparing the parametric behaviour of the triplet metastable number density, the 441�6 nm spontaneous emission and the laser output power. Unlike positive column He-Cd + lasers, Penning ionization is found to be only partially responsible for populating the upper laser level. Electron impact excitation is shown to be the major pumping mechanism for both the upper and lower laser levels, and it is the faster rate of this process for the lower level which is responsible for the observed saturation of laser power with increasing discharge current.
Far Infrared Absorption by Tetrahedrally Bonded Amorphous Semiconductors
Authors: Trodahl HJ
Published: June 2013

A discussion of the electronic structure of amorphous semiconductors is given and the ideas are developed for the case of the tetrahedrally bonded elements silicon and germanium. This background is used to interpret far infrared conductivity data taken in our laboratory. The results suggest that the void structure in these materials plays a central role in the photon-vibration coupling, particularly at low frequencies.
Stress Enhancement of the G Line of Singly Ionized Zinc in Germanium
Authors: Duff KJ , Fisher P , Butler NR
Published: June 2013

Predictions of the relative intensities of stress-induced components of the D and G lines of Zn ? in germanium are compared with the experimental results. Striking disagreement is obtained if interaction is permitted between both pairs of appropriate adjacent substates of the final states of these two transitions. However,if the Zn - is allowed to be slightly displaced from the tetrahedral substitutional site and interaction is permitted between adjacent substates then the observations can be understood provided the displacement of the Zn - from its substitutional site increases with stress and the very weak G line is split even at zero stress.
Relativistic Effects in Electron Scattering by Atoms. I. Elastic Scattering by Mercury
Authors: Sin Fai Lam LT
Published: June 2013

Elastic scattering of electrons in the energy range 0-25 eV by mercury atoms is investigated by applying a perturbation method to the (nonrelativistic) Schrodinger equation. Relativistic correction to the potential is treated using two models: a Pauli approximation and a second-order Dirac potential. The nonrelativistic Hartree-Fock wavefunction is used to describe the target in the zeroth order approximation. Electron exchange is found to be important in the collision. The relativistic correction due to mass variation makes a significant contribution, in particular to p-wave scattering which is dominated by a low energy shape resonance. Phase shifts for s-, p-, d- and f-wave scattering are presented. An analytic expression for the momentum transfer cross section for relativistic scattering is obtained. The total cross section, momentum transfer cross section, differential cross section and spin polarization are calculated and compared with experiment.
A Study of Centre-fed Antiphase Circular Antennas in a Warm Plasma
Authors: Soni KR , Arora CL
Published: June 2013

The radiation characteristics of a centre-fed antiphase circular arc antenna immersed in a warm electron plasma are studied using linearized hydrodynamic theory. The effects of antenna and plasma parameters on the radiation properties have been studied by computing the results and presenting them graphically. It is found that, whereas the power radiated in the TEM mode depends on the length as well as on the angle of the arc antenna, the power in the LP mode is independent of the angle and depends only on the length of the arc. It is also found that the power in the LP mode is relatively much larger in the case of small angled centre-fed antiphase arc antennas. Hence small angled arcs should be suitable for the launching of plasma waves, whereas large angled arcs will be more useful for communication through a plasma medium.
Zenith Angle Dependence of Cosmic Ray Shower Development from Observations of the Time Structure of Atmospheric Cerenkov Pulses
Authors: Clay RW , Thornton GJ
Published: June 2013

The attenuation of extensive air showers has been studied using atmospheric Cerenkov techniques. Observations over a range of zenith angles are correlated and an attenuation length of 234 � 38 g cm ? 2 obtained for showers with sea-level sizes of ~ 106 ?
Fluxoid Dynamics in Relativistically Streaming Plasmas
Authors: Burman RR
Published: June 2013

When particle inertia causes the magnetohydrodynamic flux-freezing condition to fail, a fluxvorticity conservation theorem can be valid: for relativistically streaming, multifluid. pressure-free plasmas, each species has a 'fluxoid' that is frozen-in to its motion. Here, fluxoid dynamics is treated with particular reference to the effects of scalar partial pressure gradients corresponding to nonrelativistic thermal speeds. Several forms or the theorem are given, including explicitly covariantones valid in general relativity. The circumstances under which the separate contributions to the fluxoid law have significant effects on fluxoid dynamics are made clear by order-or-magnitude analysis. The case of steadily rotating systems is developed and used to investigate the applicability or the fluxoid theorem to pulsar magnetospheres.
The Low-lying Levels of 13C and 13N
Authors: Barker FC , Ferdous Nasima
Published: June 2013

An attempt is made to give a consistent account of observed properties of the low-lying levels of the mirror nuclei 13C and 13N. In the first stage of this analysis, least squares fits of the data are made using R-matrix formulae in the one- and two-level approximations; in the second stage, the resultant parameter values are compared with shell model predictions. Fitted properties include level widths, neutron scattering data, El radiative widths and El capture cross sections .. The R-matrix formulae include external contributions to the El transition matrix elements, calculated using wavefunctions with the correct asymptotic forms. Acceptable fits are obtained for channel radii in the range 4-6 fm, with the lower values preferred. The parameter values obtained in these fits agree with shell model predictions, except for quantities involving the t - levels. Level displacement energies are calculated from the fitted parameter values. A reasonable account is given of two notable asymmetries between 13C and 13N-the very different excitation energies of the first excited states and the very different strengths of the El decays of these states.
Nuclear Systematics in the Interacting Boson (IBA) Model
Authors: Morrison I
Published: June 2013

Within the framework of the interacting boson approximation, simple analytical formulae are presented for analysing the mass dependence of particle transfer, inelastic scattering and electromagnetic decay from experimental data in nuclear physics. It is shown that the identical boson model provides a useful tool to correlate the results of these experiments and that the extension to equivalent proton and neutron bosons leads to some new and interesting results in the Pt-Hg mass region, namely the possibility of phase transitions and symmetry breaking.
Angular Correlations in Electron?Atom Scattering
Authors: F Williams James
Published: June 2013

The principles of angular correlation coincidence experiments are discussed in relation to electron impact excitation of atoms. Examples are given of the resolution of triplet states above the 14�7 eV dissociation limit of H2 and of the determination of differential cross sections for the magnetic sublevels of the 2p state of atomic hydrogen.
Enumeration of Group Invariant Quartic Polynomials in Higgs Scalar Fields
Authors: Wybourne BG
Published: June 2013

The. properties of Schur functions are used to enumerate the terms that must appear in a G-invariant symmetric quartic polynomial constructed from a set of Higgs fields. The importance of classifying Higgs fields as to their orthogonal, symplectic or complex representations is emphasized. The peculiar difficulties associated with symplectic irreps are noted. The groups SUs and SOlO are used to provide examples of the methods developed.
Analysis of Angular Distributions of Heavy-ion Transfer Reactions
Authors: Mohr CBO
Published: June 2013

Proceeding as in our earlier analysis of elastic scattering, but with a form for the S matrix appropriate for transfer, peaked at the critical value Ie and with width parameter .d, it is shown how to analyse the angular distribution of transfer reactions of heavy ions to obtain.d. The effect of the nuclear phases is found not to be of such fundamental importance as in elastic scattering. Analysis of theexperimental data reveals an increase of.d with nuclear size especially at low energies, but an increase of nuclear penetration for transfer collisions of the lightest nuclei. The circumstances in which strong coupling might occur between elastic scattering and transfer are examined.
Empirical Lineshape for Computer Fitting of Spectral Data
Authors: Price DC
Published: June 2013

The usefulness of the pseudo- Lorentzian as an empirical lineshape function for fitting a wide variety of spectral data is pointed out. As examples, its approximation to the universally important Voigt profile, or Doppler integral, is documented and its application to fitting saturated absorption lines is indicated, with particular reference to saturated Mossbauer lineshapes.
New Classical Solutions to F4 Theory
Authors: Jeffery EA
Published: June 2013

The partial differential equation 02rf>+m2c/>+Ac/>3 = 0 (where 0 2 = 0;-\72) is converted to the ordinary differential equation 2�>/du2 + (Nlu)d�>ldu +m2c/> +).�>3 = O. In this conversion, 02U and (OU)2 are assumed to depend only on u, where u is a Fnction of x,y, Z, t, and further, Nlu is the normal curvature of the hypersurface u = constant. In order to solve for u, the analogous Euclidean 4-space problem with 0 2 = 0; +\72 is examined initially. The only possible values of N are then 0, 1, 2, 3 corresponding to hypersurfaces that are a hyperplane, a hypercylinder (one curved face), a hypercylinder (two curved faces) and a ypersphererespectively. These hypersurfaces are transformed to Minkowski space via xk ~ ixk , k = 1,2,3. Then by solving the ordinary differential equation new solutions to the original partial differential equation are found, one of which has a closed form.
Proton-Proton Total Cross Sections and the Neglect of Masses in Data Fitting in the Regge Region
Authors: Kamran Mujahid
Published: June 2013

It is shown by taking the example of pp total cross .sections that the use of the approximation s ~ 2qs-t while fitting data in the Regge region can be misleading. Several standard fits to O"tot(pp) data are based on the assumption of weak p-f-w-A2 exchange degeneracy (EXD). However, these fits involve the use of the approximation mentioned. We find, quite surprisingly, that it is impossible to fit the O"tot(pp) data in the range 6 ~ Plab ~ 2092 GeVjc using the precise factor 2qs~ in conjunction with weak p-f-w-A2 EXD. OUf investigation shows that O"tot(pp) data alone seem to indicate either a breaking of weak p-f-w-A 2 EXD or the presence of low-lying contributions, or both, provided one does not ignore the masses of the interacting particles in data fitting in the Regge region (Plab ;:;: 5 GeVjc). Caution is therefore urged in the use of such approximations in phenomenological calculations.
Solution with Third-order Accuracy for the Electron Distribution Function in Weakly Ionized Gases (or in Intrinsic Semiconductors): Application to the Drift Velocity
Authors: Cavalleri G
Published: June 2013

The first four components 10, I" 12 and 13 of the expansion in Legendre polynomials of the electron distribution function I are shown to be of order t:D, et, e2 and e3 respectively, with e = (m/M)'/2 where m and M are the masses of the electron and molecule respectively. This allows the solution of the so-called P3 approximation to the Boltzmann equation applied to a weakly ionized gas (or to an intrinsic semiconductor) in steady-state and uniform conditions and for dominant elastic collisions. However, nonphysical divergences appear in 10 and in the drift velocity W. This can be understood by the equivalence of the Boltzmann-Legendre formulation and the mean free path formulation in which a Taylor expansion is performed around the 'origin', i.e. for a -+ 0, where a = eE/m is the acceleration due to an external electric field E. Indeed, one sees that the expansion under the integral sign (integrals appear in the evaluation of transport quantities) leads to divergent integrals if the expansion is around a = O. Fortunately, it is easy to perform a Taylor expansion around a oft 0 in the mean free path formulation and then to find the corresponding expansion in Legendre polynomials outside the origin. In this way, explicit convergent expressions are found for 10, I" 12, 13 and W, with third-order accuracy in e = (m/M)'/2. This is better than the best preceding expression, that by Davydov-Chapman-Cowling, which has first-order accuracy only (it is the solution of the P, approximation to the Boltzmann equation).
Flux Densities at 8·87 GHz of 347 Small-diameter Radio Sources
Authors: Shimmins AJ , Bolton JG
Published: June 2013

Flux densities at" 8�87 GHz (A = 3�4 cm) have been determined with the Parkes 64 m telescope for 347 radio sources, using an improved on-off integration method. The sources were selected from the Parkes 2700 MHz catalogue as those having estimated flux densities at 8�87 GHz greater than 0'5 Jy (= 0�5 x 1O- 26 Wm-2 Hz-I) and relatively small angular sizes. A total of 156 of the sources are identified with QSOs and 58 with galaxies, and 133 have not been optically identified. Of the 347 sources 101 have been previously measured at this frequency at Parkes. Some of these repeats were made to check variability and others to compare the flux density scale with that of previous measurements. The estimated accuracy of most of the measurements is � 0�034 Jy (r.m.s.) due to noise and confusion and 3�0 % due to other causes.
Profile Refinement of Single Crystal and Powder Data: The Accuracy of Crystallographic Parameters
Authors: Hewat AW , Sabine TM
Published: June 2013

Sakata and Cooper have recently published a comparison between profile refinement (in which each ordinate of the diffraction pattern is included separately in the least squares analysis) and, what they term, integrated intensity refinement (in which the ordinates are first summed over each Bragg peak). They find different results for the two methods and conclude that the results obtained from profile analysis are wrong. We show analytically that the two methods give identical results, and that the Sakata and Cooper analysis is in error because of the method they used to estimate integrated intensity. It is verified, using simulated data, that profile analysis gives lower values for the standard deviations of crystallographic parameters than simple ordinate summation.
The Effect of Discharge Depth on Contaminant Dispersion in Turbulent Open Channel Flow
Authors: J Gabric Albert
Published: June 2013

The transport and diffusion of neutrally buoyant, conservative contaminants in an open, finite depth channel is analysed at times before uniform mixing over the depth has occurred. Analytical expressions for the total mass at a given depth, the centre of mass and the variance of the contaminant patch are presented.
The Orbit-Lattice Interaction for Lanthanide Ions. III. Superposition Model Analysis for Arbitrary Symmetry
Authors: Chen SC , Newman DJ
Published: June 2013

Explicit formulae are obtained for the superposition model contributions to phenomenological orbit-lattice parameters for sites of arbitrary symmetry. As an example, these results are applied to derive expressions for the orbit-lattice parameters in C3h and D3h symmetry, without the assumption of uniform strain.
The Parkes 2700 MHz Survey: A Resurvey of the ± 4° Declination Zone
Authors: E Wright Alan , L Jauncey David , Bolton JG , Savage Ann
Published: June 2013

The + 4� declination zone of the Parkes 2700 MHz survey has been resurveyed with the Parkes 64 m telescope. The catalogue of 822 sources is complete to a limiting flux density of 0�25 Jy (= 0�25x 10- 26 Wm-2 Hz- 1), substantially lower than the original (1971) survey. All but one of the sources have flux density measurements at 5000 MHz. Appreciable changes in flux density have been found for 20% of the sources in the original survey and 59 new optical identifications ha ve been made.
Corrigendum: Simple Theory of the 'Negative Residual Linewidth' in Reflection Spectroscopy of Magnetically Concentrated Local Moment Systems
Authors: Stewart AM
Published: June 2013

The reference to Hasegawa should read:
The Anharmonic Temperature Factor for Crystals with the Hexagonal Wurtzite Structure and Its Inclusion in Models for Least-squares Refinement of Intensity Data
Authors: Fakineos A , Stevenson AW , Barnea Z
Published: June 2013

The anharmonic temperature factor for binary compounds of the ANB8-N type possessing the wurtzite structure is derived as a perturbation expansion about the harmonic case. The terms in this expansion are obtained from combinations of spherical harmonics. The derivation utilizes group theory and follows the treatment of Von der Lage and Bethe (1947) and Nizzoli (1976). A set of constraints between the cubic anharmonic coefficients in the one-particle potential (OPP), which appear in the temperature factor, is then derived, enabling least-squares refinements to be carried out successfully. The use of the anharmonic temperature factor, with these constraints, is shown to result in a significant reduction in Hamilton's R factor for two extensive data sets.
A Semi-empirical Law for Sputtering in Plasma Devices
Authors: Cook JL , Rose EK , Connolly JW
Published: June 2013

A general law is given for sputtering coefficients as a function of the energy of hydrogen and helium isotope ions incident on metallic and graphite walls and limiters. The average over a Maxwellian spectrum is performed analytically.
The Physics of Macromolecules
Authors: Mason Peter
Published: June 2013

The long, flexible, chain-like macromolecules playa major role in our existence. As carbohydrates they are the central link in the food chain of all living things; as rubbers they enable the world's transport system to function; as textiles they clothe us, whilst as plastics they serve us in a thousand ways. Above all, perhaps, as biopolymers they constitute most of the interesting parts of ourselves. Physical interest in these varied materials ranges from the shape and size of individual molecules to properties such as the strength, elasticity or dielectric behaviour of amorphous and paracrystalline polymers. Mechanical behaviour is examined in relation to four separate states of polymers: rubberlike, glassy, viscoelastic and partially crystalline. Examples of biopolymers and synthetic polymers are described and the role of viscoelasticity in the performance of motor car tyres is discussed.
Some Properties of Radio Galaxies in Clusters
Authors: Slee OB , Wilson IRG , C Siegman Betty
Published: June 2013

We present a statistical survey of the properties of 148 radio sources that are highly likely to be in AbeI1 clusters, and compare them with 127 identified field sources with the same range of redshifts from the Culgoora-3 list.
H2O Masers in the Galactic Plane. I. Longitude 340º to the Galactic Centre
Authors: Caswell JL , Batchelor RA , Forster JR , Wellington KJ
Published: June 2013

Twenty-five new H20 masers in the southern galactic plane have been discovered using a 22 GHz maser receiver on the Parkes telescope. The search was conducted at the locations of all the known 1665 MHz OH masers in the longitude range 340� through the galactic centre to 2�; of the 46 type I OH masers 38 are now found to have an H20 maser nearby; three other main-line OH emitters, possibly unusual late-type stars, also show H20 emission. We give an up-to-date tabulation of all 46 currently known H20 masers in the region which includes for completeness several H20 masers with no readily detectable associated type I OH emission.
Cross Sections for Electron?Carbon Monoxide Collisions in the Range 1?4 eV
Authors: Haddad GN , Milloy HB
Published: June 2013

The scattering of electrons from CO molecules has been studied over the energy range from 1 to 4 eV by analysing drift velocity data for pure CO and CO-inert gas mixtures at 294 K. The validity of using the so-called 'two term approximation' for the velocity distribution function in the solution of the Boltzmann equation to analyse drift velocity data for the pure gas (and thus also for the gas mixtures) has been established. The momentum transfer cross section for CO has been determined in the energy range 1-4 eV, and the measurements of the vibrational cross sections by Ehrhardt et al. (1968) have been renormalized. By using a solution of the Boltzmann equation which avoids the two term approximation, these cross sections have been shown to be consistent with previous measurement.s of the transport parameter D 1.1 fl in pure CO.
Determinantal Representations for the Crystallographic Point Groups
Authors: Duff KJ , Salib EH
Published: June 2013

A table of the values of the determinants of the representation matrices for the crystallographic point groups is given to facilitate the application of some recent theorems concerning determinantal wavefunctions.
The Australian High Resolution Neutron Powder Diffractometer
Authors: Howard CJ , Ball CJ , Davis RL , Elcombe MM
Published: June 2013

The high resolution neutron powder diffractometer installed on the AAEC HIFAR reactor at Lucas Heights is described. The resolution is in good agreement with predictions and, although below the most optimistic estimates, the intensities are usable. Examples are given of problems solved using the diffractometer which could not have been solved either by X-ray diffraction or by use of a conventional neutron powder diffractometer. Plans for diffractometer development are outlined.
A Covariant and Unitary Equation for Single Quantum Exchange
Authors: Pierre Noyes H , V Lindesay James
Published: June 2013

By requiring the 'bound state' of particle and quantum to have the mass of the particle and be physically indistinguishable from the particle we derive fully covariant and unitary equations for particle-particle scattering; these reduce to the Lippmann-Schwinger equation for Yukawa potential scattering in the nonrelativistic kinematic region and provide a new definition of the 'nuclear potential'.
Note on Nuclear Disintegration Widths
Authors: Swiatecki WJ
Published: June 2013

Symmetric expressions for fission and neutron (or other particle) emission widths rr, rn etc. are erived by applying uniformly the canonical version of the transition-state method to both cases. The resulting expression for the ratio I'o/ rc etc. is somewhat different from conventional formulae.
An Estimate of the Flux of Free Quarks in High Energy Cosmic Radiation
Authors: McCusker CBA
Published: June 2013

The flux of quarks in air shower cores at sea level is estimated from four different types of experiments. All four estimates agree and yield a quark flux of 8 x 10-12 cm-2 s- 1 sr- 1 ? The calculated concentration of quarks in the Earth's crust resulting from this flux is compared with that found in niobium in the Stanford quark search.
Diffusion, Attachment and Attachment Cooling of Thermal Electrons in Oxygen and Oxygen Mixtures
Authors: Hegerberg R , Crompton RW
Published: June 2013

The Cavalieri electron density sampling technique has been used to measure the diffusion and attachment rate coefficients for thermal electrons in O2, and in O2–N2 and O2–C02 mixtures. The observed pressure dependence of the three-body attachment rate coefficient va/N2 is shown to be caused by the selective removal of electrons from the distribution at the attachment resonance energy, and the magnitude of this effect (so-called 'attachment cooling') is shown to be a measure of the magnitude of the rotational excitation cross sections in O2 and N2. Three-body rate coefficients for the formation of O2 involving O2, N2 and CO¯2 as third bodies have been found to be 2.2,011 and 3.5 X 10¯30 cm6 S¯l respectively. The value of the diffusion coefficient ND for thermal electrons in O2 is found to be (37 � 3) x 1021 cm¯1s¯1.
Townsend Discharges in Transverse Magnetic Fields
Authors: Blevin HA , Brennan MJ
Published: June 2013

Expressions are derived for the electron concentration in Townsend discharges in the presence of a transverse magnetic field for both steady state and pulsed conditions. These results indicate that the two components of the electron drift velocity and the four diffusion coefficients required to describe the concentration distribution can be determined by observation of photons emitted from the discharge.
Toroidal Flow in Axisymmetric Pulsar Magnetospheres
Authors: Burman RR
Published: June 2013

This paper deals with dissipation-free toroidal flow in steadily-rotating axisymmetric pulsar magnetospheres; for each species, relativistic inertia is balanced by the Lorentz force. A complete integral for such flows is obtained; precise corotation with the star corresponds to a singular solution. Except for the case of corotation, all quantities follow from a single scalar quantity, which is determined by the Stokes stream function of the magnetic field. A fundamental differential equation for the problem is obtained. Particular attention is paid to flows that tend toward corotation as the symmetry axis is approached, and implications of the results for model building are discussed.
Corrigendum: Electric Quadrupole Excitation of the First Excited State of 11B
Authors: Fewell MP , Spear RH , Zabel TH , Baxter AM
Published: June 2013

The correction to the value of B(E2; t - ~ t --) due to the effect of the ground-state quadrupole moment was applied with the wrong sign. Thus lines 6 and 7 of p. 507 should read ' ... and the ground-state quadrupole moment produces a decrease of 13%...' Consequently, the result of the experiment is B(E2; t - ~ t -) = 2�6�0�4 e2 fm" corresponding to 3�5 W.u. The conclusions of the paper are not affected.
Power-law Form of the Temperature Dependence of the Magnon Specific Heat CM(T) in Linear, Planar and Spatial Antiferromagnets
Authors: Joshua SJ
Published: June 2013

The power-law form of the temperature dependence of the magnon specific heat has been calculated for some real, low dimensionality antiferromagnetic crystals. The simple power laws predicted from dimensionality considerations are reproduced in the low temperature, non-interacting spin-wave approximation, but with limited validity.
Tight-binding Central Interaction Model for the Band Structure of Silicon
Authors: Betteridge GP
Published: June 2013

We consider a simple tight-binding model involving all interactions between first and second nearest-neighbour (n.n.) bonds in the diamond lattice. We show that the band structure may be solved analytically in the central approximation in which all second n.n. bond interactions of the same type, for example all bonding: bonding or all bonding: antibonding interactions, are considered equal. The k dependence of the solution is given in terms of the corresponding s-band eigenvalues, which are determined by the topology of the structure.
Solar Electricity and Recent Progress in Thin Film Photovoltaics
Authors: Haneman D
Published: June 2013

Current methods of producing electricity from solar energy are summarized. The role of photovoltaics is described and the increasing importance of thin film technology. The photovoltaic industry is doing well over $108 worth of business in 1984 with a growth rate of about 50 % p.a. Already over 15 % of the output is in the form of thin films, practically all as amorphous hydrogenated silicon. A number of other thin film systems are being actively explored, most of them semiconductor heterojunctions, including CdS: Cu2S and CuInSe2 : CdS. The problems of durability and cost effective production are yielding under major research and development efforts on thin semiconductor films and interfaces.
L-subshell X-ray Production by 100?250 keV/a.m.u. Ions
Authors: Harrigan MF , Spicer BM , Cohen DD
Published: June 2013

Individual L-subshell ionization cross sections have been measured for bombardment of 100-200 keY H+ ions in 10 keY steps upon a thick Gd (Z = 64) target and for bombardment of 600-1000 keY He+ ions in 100 keY steps upon thick W (Z = 74) and thick and thin Au (Z = 79) targets. Experimental results for the individual L subshells are compared with the theoretical predictions of the ECPSSR theory as developed by Brandt and Lapicki. The differences are discussed as a function of the reduCi:,d ion velocity. The occurrence of collision induced intra-shell transitions is discussed as a possible source for the discrepancy between experiment and theory.
The Relationship between r .f. Current Drive and the Measured Loop Voltage in Tokamak r.f. Heating Experiments
Authors: Hugrass WN
Published: June 2013

The properties of tokamak discharges are known to undergo noticeable variations during r.f. heating. In particular, a significant drop in the loop voltage has been observed in a number of experiments, which can be attributed to a decrease in the plasma resistance or inductance or to 'r.f. current generation'. The problem is analysed from the circuit theory point of view. The ambiguities encountered in interpreting the loop voltage measurements in 'small' tokamak experiments are discussed.
The Electrical Resistance of the Lower Consolute System 2,6-Lutidine?Water
Authors: Collings AF , Bajenov N , Inglis BD
Published: June 2013

The one-phase electrical resistance of the lower consolute system 2,6-lutidine-water has been measured in the reduced temperature range 2x 10-6 < 8 < 0�11. Particular attention has been given to the drift in resistance and separation temperature caused by the leaching of ' ions during long contact with glass surfaces. When correction is made for this effect, no contribution to the electrical resistance due to critical fluctuations is observed. The effect of the leaching of ions has not been taken into account in previously published studies which have observed, and attempted to characterize, a weak divergence in the electrical resistance of critical binary mixtures.
Corrigendum: Atomic X-ray Transition Probabilities: A Comparison of the Dipole Length, Velocity and Acceleration Forms
Authors: Quiney HM , Larkins FP
Published: June 2013

All the expressions given in Table 1 (p. 47) must be multiplied by -}3/-}2 and the numerical values in Tables 2-4 by 3/2. Due to a typographical error, the coefficient of the matrix element for process C [ls]-[2p2(lS)]3p should be --}2/3 and not --}2/-}3 as printed.
Corrigendum: Absolute Cross Sections of Proton Induced Reactions on 65Cu, 64Ni and 63Cu
Authors: Sevior ME , Mitchell LW , Anderson MR , Tingwell CIW , Sargood DG
Published: June 2013

In the analysis of the 64Ni(p, y)65CU cross-section data (Fig. 2, p. 467), insufficient weight was placed on the influence of resonance to ground state transitions. When these transitions are properly taken into account, the measured cross section is increased by amounts varying from 5 % to 30 % for individual points. A plot of the revised data, together with the predictions of the statistical model code HAUSER*4 is now presented