bluuebunny/crossref_metadata_2025 huggingface dataset:
Minor Meteor Showers of October Observed over Waltair during 1962?71
Authors: Srirama Rao M , Gopalakrishna Murthy A
Published: June 2011

Systematic visual observations of meteors have been made over Waltair Qat. 17� 5� N.) in the month of October during 1962-71. From the data for 1835 meteors collected, after identification of 436 Orionid and 153 Taurid major shower meteors, 56 groups covering 439 meteors in the remainder have been observed to display common radiant points on the daily plotted meteor maps. These 56 groups are tentatively classed as minor meteor showers, after applying some tests of significance. The list is reduced to 20 groups by identifying common radiant coordinates within a divergence of � 10�. Of these 20 groups, 10 occur in at least two different years and on nearby dates and therefore are considered to be well-established minor meteor showers. It is found that a majority of the minor shower radiants lie close to the ecliptic.
Recombination Lines near 6 cm Wavelength in the Large Magellanic Cloud
Authors: McGee RX , M Newton Lynette , Brooks JW
Published: June 2011

Recombination lines H 10901: have been detected in eight sources in the Large Cloud of Magellan. Low ratios of line temperature to continuum temperature, TL/Tc, were found in most of the sources and are attributed to the difficulty of obtaining a true continuum value when such a large area is encompassed by the telescope beam. In the 30Doradus nebula the ratio N(He+)/N(H+) was found to be no greater than O' 08, or less than half that previously recorded by radio observations.
The Inverse Scattering Problem for Spherical Polydispersion
Authors: HJ McKellar Bruce
Published: June 2011

It is shown how the mean form factor for Rayleigh-Gans scattering from a spherical polydispersion may be inverted to obtain the size distribution of the polydispersion.
The Determination of Ion?Atom Interaction Potentials
Authors: Milloy HB , Watts RO , Robson RE , Elford MT
Published: June 2011

It is shown that given the present state of both theory and experiment the magnitude and form of the well in the interaction potential for an ion-atom system cannot be determined by comparing measured and predicted transport coefficients. The theory of Kumar and Robson (1973) is used to demonstrate that significantly different interaction potentials can be used to predict essentially the same transport coefficient data. Alternative techniques for determining the potential well are discussed, with particular emphasis on the possibility of analysing differential cross-section measurements taken under conditions where the rainbow oscillations are masked by the resolution of a typical apparatus.
The Mobility of H+3 and H+5 Ions in Hydrogen
and the Equilibrium Constant for the Reaction
H+3+2H2<=> H+5+H2 at Gas Temperatures of
195, 273 and 293 K
Authors: Elford MT , Milloy HB
Published: June 2011

The mobilities of hydrogen ions in hydrogen have been measured by the Bradbury-Nielsen time-offlight method at temperatures of 195, 273 and 293 K, at pressures in the range O' 5-200 torr and at E/ N values ranging from 0�4 to 200 Td. The zero field reduced mobilities of H~ and H~ have been determined to be 1l�18�0�05 and 10'61�0'05cm2 s-1 V-1 at 293K, and 1l�18�0�05 and 10'53�0'05cm2 s-1V-1 at 273�2K respectively. At 194'5K the zero field reduced mobility of H~ was determined to be 10�40�0�05 cm2 s-1V-1 ? The thermal equilibrium constant K. for the reaction H~ + H2 + H2 +2 H~ + H2 was obtained by fitting the mobility data as a function of gas pressure. The values of K. obtained were 1�83�0�45 X 10-18, 2�8�0�7 X 10-18 and 1'6�0'6 x 10-16 cm3 at 293,273 and 195 K respectively. The reduced mobility of Hj as a function of E/N was derived for values of E/ N up to 200 Td from the data taken at gas pressures less than 2 torr and was found to be in good agreement with the data of Miller et al. (1968). The ion species present were identified by the addition of contaminants and by use of supplementary data taken with a drifttube- mass-spectrometer system. The energy for the dissociation of H~ into Hj and H2 was derived by the method of Eyring et al. (1936) and found to be 250� 50 meV.
Simple Description of Anharmonic Phenomena in Cubic Crystals
Authors: Field DW
Published: June 2011

A simple spherically symmetric single-atom potential expression in the form of a series expansion in the atomic displacement is assumed to describe the potential energy of each atom in monatomic cubic crystals from room temperature to their melting point. Expressions are derived to account for thermal properties such as melting point and thermal expansion. Calculated results for 13 cubic metals are compared with experimental values. The model accounts for the broad trends in the experimental data and provides an estimate of the extent of anharmonicity to be found in these simple solids.
The Decay of 147Nd
Authors: Rangacharyulu C , Chaturvedi SN , Mehta GK , Nath N
Published: June 2011

An experimental level scheme has been determined for 147Pm from an investigation of the decay of 147Nd which employed a high resolution Ge(Li) detector and a sum-coincidence spectrometer with fast-slow coincidence. Conclusive evidence is presented for the existence of levels in 147Pm at 182,228�5,275,319�5 and 725 keY besides the six already established levels, while no evidence is found for another six levels suggested by some earlier workers. Thirty-two y-ray transitions and their cascade relations have been established, and relative intensities have been determined for most of the transitions.
Pulse Spacing Distribution of VHF Rural Wideband Radio Noise
Authors: Clay RW
Published: June 2011

VHF radio noise has been studied in a rural environment with a large bandwidth. The pulse spacing distribution is similar to that of random Poisson-distributed pulses over periods of a few minutes, but over longer periods the mean pulse rate changes causing the long-term pulse spacing distribution to exhibit a more complex form.
The Application of the String Model of Hadrons to the Inelastic Scattering of Electrons
Authors: Tassie LJ
Published: June 2011

A simple string model of hadrons, which is in agreement with scaling, is applied to the deep inelastic scattering of electrons by the nucleon and is used to make predictions of the average charge and the types of particles produced. In particular, the total baryon number of the particles produced in the photon fragmentation region is shown to be 0 for x ~ 0 and 1 for x ~ 1, where x is the Bjorken scaling variable.
Electron Diffusion in Finite Enclosures
Authors: I Leemon Howard , Kumar Kailash
Published: June 2011

Starting from the two-term approximation to the Boltzmann equation, a study is made of the time dependence of the density of electrons released inside a finite enclosure containing a neutral gas. The dominant behaviour can be represented by a diffusion equation containing an effective diffusion constant which depends upon pressure and dimensions of the enclosure. In the limit of large pressure and large enclosure the usual expression of the diffusion constant is obtained. The approach to this limit dePends upon the electron-neutral interaction. The effect of various model and measured cross sections for some inert gases is discussed.
Phonon Dispersion Relations for Chromium and Tantalum
Authors: Prakash Jyoti , Pathak LP , Hemkar MP
Published: June 2011

Phonon dispersion curves for the normal modes of vibration in chromium and tantalum are calculated along the symmetry directions [100], [110] and [111] using the five force-constant model of Behari and Tripathi (1970a). The results are compared with experimental values obtained from inelastic neutron spectroscopy and reasonably good agreement is found.
A Digital Method for Computation of Time-varying Power Spectra Applied to Geomagnetic Pi Pulsations
Authors: Yuan FFF
Published: June 2011

A digital method of computing time-varying power spectra involving complex demodulation followed by low pass filtering is described. The method is illustrated by an application to records of geomagnetic Pi pulsations from Macquarie Island. These show a steady decrease in power with increasing frequency in the range O� 1---{)' 5 Hz.
Electron Distribution Moments and Precipitation Dependence on Anisotropic Magnetospheric Content
Authors: Catchpoole JR
Published: June 2011

Precipitation of spiralling electrons from the magnetosphere is investigated, under cceleration by field line convergence and by superimposed electric field. Instead of an isotropic content, packets of electrons of fairly narrow pitch range are considered.
Total Yield Measurements in 31P(p, g)32S
Authors: O'Brien R , Switkowski ZE , Smith AK , Sargood DG
Published: June 2011

The reaction 31p(p, )I)32S has been investigated in the proton energy range 0�33-1�75 MeV. Total )I-ray strengths were determined for 28 resonances. Yield curves were measured over limited portions of the energy range, which between them covered the whole range. An estimate of the nonresonant cross section was obtained, and total resonance widths were deduced.
The Nature of D-region Scattering of Vertical Incidence Radio Waves. II. Experimental Observations Using Spaced Antenna Reception
Authors: Lindner BC
Published: June 2011

Statistical properties of the ground diffraction pattern formed by ionospherically reflected radio waves are used to examine models of the angular spectra of reflections from the ionospheric D-region. In the daytime two distinct height regions characterized by differing reflection mechanisms are identified within the D-region. Below 85 km the angular spectrum of reflected waves frequently contains coherent components, whereas a spectrum of incoherent or randomly phased components is characteristic of reflections from the region above 85 km. There is evidence which suggests the presence on many occasions of isolated moving reflectors in the reflecting 'ionospheric screen' . . Both the mean angular spread and the fading speed of waves partially reflected from the D-region show an increase with increasing height of reflection.
The Parkes 2700 MHz Survey (Eighth Part). Catalogue for the Declination Zone ?65° to ?75°
Authors: Bolton JG , Butler PW
Published: June 2011

A catalogue of 515 radio sources is presented for the region between declinations -65� and -75� (0�374sr). The survey is believed to be complete to 0�22Jy at 2700 MHz (-'900 sources per steradian). Flux densities at 5009 MHz have been measured for most of the sources stronger than o� 35 Jy at 2700 MHz.
Differential Cross Sections for the 13C(3He, p0) and 15N(3He, p0) Reactions at 15 MeV
Authors: Havloujian J , Ravalli G , Spice BM
Published: June 2011

The angular distributions of the ground state proton groups from 3He-induced reactions with 13C and BN targets have been measured at a bombarding energy of 15 MeV. The DWBA program DWUCK has been used to fit the differential cross sections with no free parameters. The optical model parameters for the proton-residual nucleus channel were taken from the literature, and the 3He-target nucleus channel parameters were obtained by fitting the 3He elastic scattering differential cross sections.
Fluctuation-generated Plasma Oscillations
Authors: Tirkel AZ , Francey JLA , Troup GJ
Published: June 2011

A theory of spontaneous plasma oscillations is developed from basic equations. Longitudinal modes in a one-dimensional system are presented in detail, while possible extensions to three dimensions and the effects of external magnetic fields are indicated. The basic equations lead to a Van der Pol equation. Similarities are noted between plasmas and two-level lasers.
The Mobility of 02+ and O4+ Ions in Oxygen and the Equilibrium Constant for the Reaction O2++2O2? O4++02 at 273 and 294 K
Authors: Milloy HB
Published: June 2011

The zero-field mobilities of oxygen ions in oxygen have been measured by the Bradbury-Nielsen time-of-flight method at temperatures of 194, 273 and 294 K and at pressures in the range 0�1-3�5kPa. The zero-field reduced mobilities of 0; and 0: have been determined to be 2�248�0�015 and 2'077�0'014cm2 s-1 V-1 at both 273 and 294K. The thermal equilibrium constant for the reaction 0; +02 +02 ;:t 0: +02 , obtained by fitting to the variation of the mobility with gas pressure, was found to be (3�4�0� 5) x 10-17 and (1�2�0�2) x 10-17 cm3 at 273 and 294 K respectively.
Molecular Dynamics Calculation of the Thermodynamic Properties of Methane
Authors: Hanley HJM , Watts RO
Published: June 2011

Thermodynamic properties of methane in the dense gas and liquid states have been calculated by the method of molecular dynamics. The methane pair interactions were modelled using a spherically symmetric m-6-8 potential, and the most significant three-body and quantum effects were included. Agreement between calculated and experimental values for the energy and pressure is generally good except at low temperatures and high densities. The specific heat at constant volume is also briefly discussed.
Accurate Branching Ratio Measurements in 23Na(p, g)24Mg
Authors: Boydell SG , Sargood DG
Published: June 2011

The reaction 23Na(p, y)24Mg has been investigated in the proton energy range O' 3-1' 75 MeV. Gamma ray spectra were measured for 22 resonances with Ge(Li) detectors which were carefully calibrated for relative peak efficiencies. Allowance was made for the effect of anisotropies in all the emitted y-rays. The speCtra have been analysed to give branching ratios for bound and unbound levels.
Accurate Branching Ratio Measurements in 31P(P,g)32S
Authors: Boydell SG , Sargood DG
Published: June 2011

The reaction 3 1p(p, y)32S has been investigated in the proton energy range 0'4-1'75 MeV. Gamma ray spectra were measured for 2S resonances with Ge(Li) detectors which were carefully calibrated for relative peak efficiencies. Allowance was made for the effect of anisotropies in all the emitted y-rays. The spectra have been analysed to give branching ratios for bound and unbound levels. Comparisons made with previous work reveal some differences.
Overdriven Supersonic Heat Waves
Authors: Strachan JD , Ahlborn B
Published: June 2011

If a supersonic heat wave is overtaken by a shock, either generated externally or'induced by the sudden cooling of the wave front, an overdriven heat wave is formed which is similar to an overdriven detonation. The Mach number of the overdrlven heat wave is proportional to the product of the Mach numbers of the pursuing shock and the heat wave.
Tests of Randomness in Astronomical Objects. I. Along Single Great Circles
Authors: Wesson PS
Published: June 2011

Results are presented for the first of two extensive computer tests for nonrandomness in the interobject positions of astronomical objects. The aim is to test the two predictions: the geometrical effect that it is impossible to put an arbitrarily large number of objects on the surface of a sphere and have them all randomly equivalent; and the physical effect that any astronomical objects which occur in clumps or clusters (like galaxies) should show the predicted regular-chain effect of Scott et at. (1954). Four other physical effects expected to give rise to nonrandomness are also discussed, including the Arp hypothesis
Compton Scattering of Deuterons
Authors: Saleem Mohammad , Shaukat MA
Published: June 2011

The Compton scattering of deuterons is accounted for by treating the deuteron as an elementary particle.
Statistics of Fission Widths for Partly Open Fission Channels
Authors: Cook JL , Rose EK
Published: June 2011

Statistics of Fission Widths for Partly Open Fission Channels
A Study of Resonances in the 58Ni(p, ?)59Cu Reaction below 2·15 MeV
Authors: Din GU , Al-Naser AM
Published: June 2011

The )I-ray spectra for seven resonances in the reaction s8Ni(p, )I)S9CU in the range Ep = 1400--2150 keV have been measured with a high resolution Ge(Li) detector. Consistent resonance decay schemes have been derived along with the decay schemes of bound levels. Decays to previously unreported bound levels at 2� 459, 2� 711 and 3� 025 MeV have been observed, while results significantly different from the earlier reports have been obtained for the decay of most of the bound levels. The reported level at 1� 865 MeV is confirmed. The decay schemes of the two resonances at Ep = 1424 and 1844 keV indicate that these are T = 3/2 analogue states associated with the levels at O' 880 and 1�301 MeV in s9Ni. A new value of Q = 3'415�0'OO3 MeV for the reaction S8Ni(p, )I)59CU was derived from the Ge(Li) spectra.
Nonlinear Diffusion of Ions in a Gas
Authors: Robson RE
Published: June 2011

The evolution in time of an initially closely bunched group of ions in a neutral gas is examined by solving a model kinetic equation, and limits to the validity of the linear law of diffusion (Pick's law) are established. The implications of nonlinear diffusion processes for determination of ion transport coefficients in drift tube experiments are discussed.
Anisotropic Diffusion in Electron Swarms
Authors: Francey JLA , Jones DA
Published: June 2011

We show that the distribution functions derived by Parker (1963) in his analysis of the TownsendHuxley experiment can be used to calculate DL/D, the ratio of longitudinal to isotropic diffusion coefficients for electron swarms in electrostatic fields in gases. In the case of a constant collision frequency interaction our results agree with previous calculations, whilst for a constant mean free path we find DL/D = 0�58. This result is some 16% higher than previously published values but provides better agreement with experiment for electrons in helium.
Downhole Induced-polarization Detection of Ore Bodies: Conductive Overburden Effects
Authors: Gleeson LJ , Thio Y-C
Published: June 2011

Highly c.onducting .overburderi layers inhibit the surface detecti.on .of .ore b.odies by induced p.olarizati.on (lP) measurements. The excitati.on and resp.onse .of an IP s.ource .obtained by means .of undergr.ound (d.ownh.ole) electr.odes is investigated utilizing a simple m.odel: the .overburden is represented by a unif.orm surface layer and the .ore b.ody by a small sphere. The shielding .of the s.ource from the surface is shewn. Quantitative estimates .of the improvement .obtained by siting the electr.odes bel.ow the .overburden-h.ost-rock interface are .obtained. It is expected that similar impr.ovement will be .obtained with larger .ore b.odies. It is shewn that the impr.ovement applies t.o time-d.omain and frequency-d.omain measurements. A feature .of the results is the presence .of a 'blind' z.one just beneath the interface. The .optimizati.on .of electrode p.ositi.ons in a particular ge.ometry is examined.
On the Interpretation of the Doppler Spectra of Ionospherically Propagated Ground Backscatter Echoes
Authors: Bennett JA
Published: June 2011

The mechanism giVing rise to the backscatter Doppler spectrum is discussed by means of a simple model. Attention is focused on the effect of movement of the region contributing to the echo which arises from time changes in the group velocity within the ionosphere. It is shown that the influence of these changes on the spectrum can be separated into two parts: (1) A change in the maximum possible width of the spectrum as a result of the change of the time for which an indiVidual scatterer is contributing to the echo; this effect is independent of the scatterer distribution. (2) A possible narrowing of the spectrum as a result of the way in which the signals from individual scatterers combine; this effect depends upon scatterer distribution. Scatter from a fixed'scattering surface and from dispersive waves (e.g. sea waves) is considered. A tentative extrapolation of the results to a more realistic model suggests that neither effect is likely to be significant in practical highfrequency radio experiments (except at short ranges with highly directional antennas), although they may be significant in acoustic wave simulations of the radio case.
Southern Hemisphere Meteor Stream Determinations
Authors: Gartrell G , Elford WG
Published: June 2011

Meteor orbits have been deduced from radio observations of meteor trails carried out at Adelaide (latitude 35� S.), using a combined multi-station continuous wave and pulse radar system operating at 27 MHz. Observations were made for one week each month during the period December 1968 to June 1969, and also during October 1969. The orbits of 1667 meteors have been determined down to a limiting radio magnitude of + 8. The data have been systematically searched for stream meteors, and the significance of minor associations has been appraised. Altogether 40� 4 % of the orbits were found to be associated with at least one other orbit, and 29� 8 % with two or more. Numerous minor streams with high inclination and low eccentricity have been found at deep, southern declinations from December to March, with little activity in this quarter during June and October. In addition to confirming several previously established cometary associations, a comprehensive search has indicated that 34 of the meteor associations found may be related to 17 comets. Associations between several long-period comets and low-eccentricity high-inclination streams appear to be indisputable, and they confirm the origin of at least some of the 'toroidal group' meteors, previously a matter of some doubt.
The Inverse Scattering Problem for Static Meson Fields and Nonlocal Potentials
Authors: Cook JL
Published: June 2011

The Inverse Scattering Problem for Static Meson Fields and Nonlocal Potentials
Shell Structure of the Even Tellurium Isotopes and Inelastic Proton Scattering
Authors: Nesci P , Smith R , Amos K , Geramb HV
Published: June 2011

The isotope variation of the inelastic proton scattering cross sections leading to the 5 - state in tellurium is explained in terms of simple configurations of neutrons in the Sl/2-<i3/ 2-hll/2 subshell.
Calculation of the Static Properties of Local Moment Systems by the Mean Field Method
Authors: Stewart AM
Published: June 2011

It is demonstrated that two different methods which have been used in the past to calculate the static properties oflocal moment systems in the mean field approximation are incomplete. A proof is given of the correctness of another method that the author has used in several previous calculations. It is found that some exact and very general relationships exist between the conduction electron magnetization and the local moment magnetization even when it is not valid to treat the interactions between the magnetic atoms by mean field theory.
Debye?Waller Factors of a-Iron and Sodium. II. Willis's Anharmonic Theory
Authors: Pathak LP , Prakash Jyoti , Singh VP , Hemkar MP
Published: June 2011

An application of Willis's anharmonic theory has been made to improve the earlier calculations of the Debye-Waller factors of (X-iron and sodium reported in Part I, and to estimate the effect of including anharmonic. terms in the crystal potential. The calculations have been compared with the existing experimental data in terms of the Debye-Waller factor temperature parameter Y. The agreement between the calculated values and the experimental results is now shown to be quite good over a wide range of temperature.
On the Classical Theory of Equilibrium Between Matter and Radiation
Authors: Monaghan JJ
Published: June 2011

The problem of establishing the Rayleigh-Jeans law for equilibrium electromagnetic radiation in a cavity is studied without making the customary simplifying assumptions. By using a Hamiltonian formalism analogous to that introduced by Fermi for quantum electrodynamics the analysis is simplified, general expressions for absorption and emission are obtained, and the correspondence with the quantum mechanical treatment is established. The model considered consists of a cavity which contains classical charged particles which move in an arbitrary potential while interacting with electromagnetic radiation. The work covers much the same ground as the fundamental but neglected work of McLaren, though the methods used are simpler and more direct. The applications are to those parts of radio astronomy where the wavelengths are sufficiently large to allow a classical description. In particular, Twiss's analysis of stimulated emission at radio wavelengths is incorporated in the analysis.
Deficiencies of the Asymptotic Solutions Commonly Found in the Quasilinear Relaxation Theory
Authors: Grognard RJ-M
Published: June 2011

Several authors have attempted to describe the dynamics of a suprathermal beam of electrons relaxing in a cold coIIisionless plasma by analytic asymptotic solutions of the quasilinear equations. These solutions are criticized on the grounds that they cannot correctly take account of the evolution of the plasma wave spectrum. A numerical solution is given which illustrates this point in the case of a homogeneous one-dimensional beam. Two important points can be made on the basis of the present work: (1) for self-consistency, the spontaneous emission terms cannot be neglected at any stage, and (2) the characteristic times of evolution in the early stages (accessible for the first time through the present numerical solutions) are found to be much longer than commonly quoted (Le. several times the linear growth time) when discussing the reasons for neglecting higher-order interactions.
Hysteresis of Primary Cosmic Rays Associated with Forbush Decreases
Authors: Rajan RS
Published: June 2011

Regression analysis of primary cosmic ray intensities during Forbush decreases indicates the existence of a differential modulation between high and low rigidity primaries.
On Stationary Distributions of Charged Dust
Authors: Banerjee A , Chakravarty N , Dutta Choudhury SB
Published: June 2011

The correct value of the ratio of charge density to mass density is obtained for a stationary distribution of charged dust with vanishing Lorentz force. It is found that the ratio is truly an arbitrary constant, in disagreement with the apparently. incorrect result obtained by Misra et al. (1972).
Measurement of the Energy Spectrum of 60Ni Recoils following 60Co Decay Using Nuclear Resonance Fluorescence
Authors: Sowerby BD
Published: June 2011

The energy spectrum of 6�Ni recoils from 60Co fJ decay in a vapour CoBr2 source has been studied by measuring the profile of the 1� 33 MeV y rays emitted by 6�Ni. The profile was deduced from the measured cross sections for resonance scattering of the 1� 33 MeV y rays in coincidence with the preceding 1�17 MeV y rays. The results show fair agreement with the profile calculated for free 60Co atoms. The influence of molecular Coulomb fragmentation and chemical binding are discussed.
On the Semi-classical Method for Electron Scattering by Atoms
Authors: Bransden BH , Noble CJ
Published: June 2011

In applications of the semi-classical approximation to excitation of atoms by electron impact, it is commonly assumed that the trajectory of the incident electron can be taken to be a straight line. The validity of this assumption is tested by comparing cross sections obtained in a coupled channel model using either a straight line trajectory or a trajectory computed from an effective potential. It is found that as far as total cross sections are concerned the assumption of a straight line trajectory does not cause appreciable error for elastic scattering at incident energies above 200 eV and for inelastic scattering above 100 eV. The influence of the choice of trajectory on the angular distributions is discussed briefly.
Crystal Field Effects in S-state Ions Due to Exchange Polarization
Authors: Newman DJ
Published: June 2011

It is shown that the matrix elements of the tensor operators describing a new type of crystal field can be calculated using the properties of the spin ~ quasi-spin transformation. The relationship of this field to electron correlation in open shells is clarified, and its contribution to the ground state splittings of S-state ions is discussed
Observations of Interstellar CH at 9 cm Wavelength
Authors: Gardner FF , Robinson BJ , Sinclair MW
Published: June 2011

The 9 cm ground-state lines of CH have been observed in southern galactic sources, mainly HII regions. The F = 0-1 transition at 3264 MHz has been detected in emission in 16 sources; the F = 1-1 transition at 3335 MHz has been seen in absorption in 5 sources and in emission in 2 others. Where the F = 1-1 transition is in absorption the transition temperature is positive and below about 100 K. The F = 0-1 transition is generally inverted, with a transition temperature between -10 and 0 K. The column densities of CH are in the vicinity of lO'4 cm-2, slightly below those for OH but many times those for H2CO. There is no correlation between apparent optical depths of CH and those for OH or H2CO absorption. There is also no enhancement of CH in the dense molecular clouds near the centre of the Galaxy.
Dual Absorptive Model and p-p Backward Elastic Scattering
Authors: Saleem M , Irshad Jawaid , Rasul Ghulam
Published: June 2011

The dual absorptive model is used to explain the structure of the differential cross section for n-p backward elastic scattering at incident pion momenta of 8 and 16 GeV/c.
Direct Reaction Inelastic Proton Scattering from 20Ne
Authors: Amos K , Nesci P , Smith R
Published: June 2011

The transition amplitudes for direct reaction inelastic proton scattering from nuclei are formulated using target spectroscopy given by angular momentum projection from axially symmetric minimal energy Hartree-Fock intrinsic states of N = Z nuclei. Applications to the scatterings from 20Neare made, from which the importance of virtual excitations of giant resonances is evident.
Extended Theory of Magnon Sideband Shapes. II. Impure Three-dimensional Antiferromagnets
Authors: Richardson DD
Published: June 2011

A phenomenological model is given for calculating magnon sideband lineshapes in the absorption spectra of antiferromagnetic crystals. The method allows an exact expression for the lineshape to be obtained when dispersion within the Brillouin zone of both the exciton energy and the exciton-magnon interaction strength is included. The effect of a substitutional spin impurity is calculated exactly, and a simple example is given which approximates the effects of an impurity on a magnon sideband in the antiferromagnetic perovskite RbMnF3 ? It is thought that the ability of the model to predict the existence of local modes and resonances justifies the simple form of the model Hamiltonians chosen. The pure crystal sideband Iineshape can also be well determined from information on the exciton dispersion and the behaviour of the exciton-magnon interaction strength within the Brillouin zone.
The Combined Effect of Rotation and Magnetic Field on Finite-amplitude Thermal Convection with Hexagonal Planform
Authors: Van der Borght R
Published: June 2011

In this paper a study is made of the combined effect of rotation and magnetic field on the convective transfer in a horizontal Boussinesq layer of fluid heated from below, in the case when the convection celIs have a hexagonal planform. The numerical integrations of the basic equations have been carried out to high values of the Rayleigh number, and two families of solutions have been discovered. A discussion of the main properties of these solutions is given.
Angular Correlations in 19O
Authors: Southon JR , Poletti AR , Beale DJ
Published: June 2011

p-y correlation measurements have been carried out on 190 levels populated by the 1BO(d, p) reaction. A cryogenically cooled thin target of lBO-enriched ice was used. Our data allow the following spin values: J(2'37) = 5/2,7/2 or 9/2; J(2'78) = 3/2+ or 7/2+; J(3'15) = 3/2 or 5/2. Previous spin assignments of 3/2 and 9/2 for the 2� 37 and 2� 78 MeY levels respectively are rigorously rejected. Mixing ratios measured for the 2,37-+0,2,78->0 and 3'15-+0'096MeY transitions agree with previous determinations. The results are discussed in terms of recent shell model and rotational model calculations on 190.
A Collective Rotational State of Spherical Nuclei
Authors: Henderson JR , Lekner J
Published: June 2011

We consider a particular many-body rotational excitation 'P of a spherical self-bound system of particles, of the form studied by Lekner (1974). This angular momentum eigenstate is translationally invariant and thus is not a spurious state. The energy of 'P is found from first principles to be substantially larger than that of the first 2+ excited states of even-even nuclei, with the exception of 208Pb. The quadrupole moment is negative, the g-factor is approximately Z/A and the lifetime is shorter than the single-particle (Weisskopf) value by a factor of the order of A/Z2. It is suggested that these states are the finite system rotational analogues of Feynman's phonons and rotons.
Theory of Temperature Modulation Studies of Ferromagnetic Materials
Authors: Wilson GVH , Chaplin DH , Sydney KR
Published: June 2011

A theoretical account is given of temperature modulation experiments on a ferromagnet sample in which the resulting voltage induced in a pick-up coil is monitored by phase-sensitive detection. Calculations are made of the effects of magnetic relaxation and of the thermal skin depth on the signal amplitude and phase. The relaxation calculations are shown to be consistent with recent experimental data for gadolinium.,
Magnetic Fields in Supernova Remnants
Authors: R Dickel John , Milne DK
Published: June 2011

Parkes 2�7 and 5�0 GHz polarization maps have been combined to obtain distributions of magnetic field, Faraday rotation and depolarization for 20 supernova remnants.
Variation in Magnetic Field Strength During a Specific Anisotropic Gravitational Collapse
Authors: Mason DP
Published: June 2011

The MHD approximation has been made in general relativity to derive expressions in terms of the fluid's total proper energy density and rest-mass density for the variation in the strength of the magnetic field during the anisotropic gravitational collapse in which the condition ?ab HaHb = 0 holds throughout the collapse, where ?ab is the expansion tensor. The physical significance of this condition is also examined.
Mach's Principle in Nonsymmetric Field Theories
Authors: L Murphy George
Published: June 2011

Most field theories allow an isolated particle to possess a rest mass, and thereby violate Mach's principle. The nonsymmetric theories of Schrodinger and of Einstein do not have this defect.
Statistical Concepts in Particle Physics
Authors: Peaslee DC
Published: June 2011

A review is given of the level density formula in hadron physics, which has reached a completely developed state on the basis of the bootstrap equation. It is shown how the approximate formula
Giant Resonances
Authors: S Hanna Stanley
Published: June 2011

A review is given of giant muitipole resonances in nuclei with emphasis on their systematic location, their great strength in terms of an appropriate sum rule and their concentration in a rather narrow region. Capture reactions as a source of information are especially considered.
Electron Scattering and Photonuclear Reactions at the MIT Bates Linac
Authors: Turchinetz W
Published: June 2011

Progress is reported in the development of the Bates Electron Linear Accelerator Facility at MIT. Preliminary data are shown for high resolution electron scattering, and for the high energy photoproton reaction on 160 and the threshold photoproduction of pions on 12C and llB.
Field Theory of Particles with Arbitrary Spin
Authors: Green HS
Published: June 2011

It is pointed out that existing field equations for particles of higher spin are unsuitable' for the formulation of field theories with interaction. ' A generalization of the Dirac and Kemmer matrices is discussed in terms of finite-dimensional representations of the de, Sitter group. ' It is shown how to formulate a general field theory in such a way as to exhibit a corresponding dynamical symmetry. The resulting field equation resembles Bhabha's, but is self-consistent in its applications to interacting particles and has a different type of mass spectrum. In the Appendix, it is shown that'within any'irreducible representation of the Poincare group there are finite-dimensional representations of the'Lorentz group'labelled (s, � s).
The Ratio of the Lateral Diffusion Coefficient to Mobility for Electrons in Argon at 294 K
Authors: Milloy HB , Crompton RW
Published: June 2011

The ratio of the lateral diffusion coefficient to mobility (DT/μ) for electrons in argon has been measured at 294 K in the range 0.001 ≤ E/N (Td) ≤ 0.1 using pressures in the range 309–1171 kPa. The total error in the best-estimate values is estimated to be less than � 2 % for E/N ≤ 0.0035 Td and less than � 1.5 % for E/N ≥ 0.004 Td. A discussion is given of the design of a Townsend–Huxley diffusion experiment in light of recent theoretical work on the influence of material boundaries on diffusing streams of charged particles and of the effects on the measurements of multiple scattering and dimer formation.
Monte Carlo Simulation of Electron Swarms in H2
Authors: Hunter SR
Published: June 2011

A Monte Carlo simulation of the motio'n of an electron swarm in molecular hydrogen has been studied in the range E/N = 1,4-170 Td. The simulation was performed for 400-600 electrons at several values of E/N for two different sets of inelastic collision cross sections at high E/N. ,Results were obtained for the longitudinal diffusion coefficient DL , lateral diffusion coefficient D, swarm drift velocity W, average swarm energy <Ii) and ionization and excitation production coefficients, and these were compared with experimental data where available. It is found that the results differ significantly from the experimental values and this is attributed to the isotropic scattering model used in this work. However, the results lend support to the experimental technique used recently by Blevin et al. to determine these transport parameters, and in particular confirm their results that DL > D at high values of E/N.
Mean Square Vibration Amplitudes in Zinc
Authors: Field DW
Published: June 2011

The structure factors of 98 independent reflections have been determined by measurement of the integrated intensities for X-ray diffraction from a zinc single crystal at 295 K. The mean square vibration amplitudes found for the two principal directions are' compared with 'other recent measurements. The X-ray Debye temperature determined from the data' is 207 � 3 K at 295 K.
Plane Symmetric Solutions of a Scalar-Tensor Theory of Gravitation
Authors: Reddy DRK
Published: June 2011

Plane symmetric solutions of a scalar-tensor theory proposed by Dunn have been obtained. These solutions are observed to be similar to the plane symmetric solutions of the field equations corresponding to zero mass scalar fields obtained by Patel. It is found that the empty space-times of general relativity discussed by Taub and by Bera are obtained as special cases.
2- States of 8Be
Authors: Barker FC
Published: June 2011

The cross sections for several reactions populating sBe in the region of the 7Be+n threshold show rapid changes, which have been attributed to a 2- threshold state. An analysis of these data using R matrix theory shows that there is considerable isospin mixing in the threshold state, implying another 2 - state nearby. A two-level R matrix approximation provides a good fit to all the relevant data, with parameters consistent with shell model calculations and with properties of sLi. Proper account must be taken of the neutron threshold in order to explain the isospin mixing. The threshold state is expected to show different widths in different reactions.
12C + 16O Elastic Scattering and Total Reaction Cross Sections Near the Coulomb Barrier
Authors: Nagorcka BN , Symons GD , Treacy PB , Maclean IC
Published: June 2011

Elastic scattering and total reaction cross sections (via y ray yields) have been measured for 160+ 12C in the c.m. energy range 5� 5-10,0 MeV. Some well-defined structure is observed, with peak widths of order 250 keV. An optical potential which fits peaks in the total reaction cross section is shown to be inadequate to explain the elastic scattering data. Possible reasons for this inconsistency, which imply the need for a more general optical potential, are discussed.
Cell Sizes at the Onset of Thermal Convection in a Fluid Layer Subject to the Influence of Rotation and a Magnetic Field
Authors: Murphy JO
Published: June 2011

A comparison is made between the theoretical and experimental cell sizes manifest at the onset of stationary convection in a mercury layer heated from below and subject to the influence of rotation about a vertical axis and a vertical magnetic field. The theoretical cell sizes have been derived on the basis of a variational technique, and the boundary conditions appropriate to the experimental situation have been applied.
The Molonglo Deep Sky Survey of Radio Sources. II. Declination Zone -62°
Authors: Robertson JG
Published: June 2011

Results are given for the second zone of a deep survey made at 408 MHz with the Molonglo cross. The catalogue lists positions and flux densities for 95 sources, none of which has been previously catalogued, in a solid angle of 5�51 x 10-3 sr. The right ascensions covered (with some excluded areas) are 18h 26m-OOh 06m, with a range in declination of 45'. The lower limit of flux density is 84 inJy. An upper limit of 1000 mJy has also been imposed. The position uncertainties are typically 12''at 100 mJy and 6# at 250 mJy.
The Molonglo Deep Sky Survey of Radio Sources. III. Source Counts
Authors: Robertson JG
Published: June 2011

Number-flux density counts of radio sources are given for the first two deep surveys made with the Molonglo Mills Cross at 408 MHz, extending to lower limits of 84 and 88 mJy. Practical techniques are developed for the calculation of corrections to the counts when confusion errors are significant. The resulting corrections due to noise, confusion and other effects are given. Counts are also given for the MC2 and MC3 catalogues in the range 2-10 Jy to reduce the statistical uncertainties there. Results are shown on a composite plot, using relevant Molonglo surveys and an all-sky catalogue of strong sources. The existence of a convergence in the number of weak sources is confirmed.
Basic Properties of the Exceptional Lie Groups
Authors: Wybourne BG , Bowick MJ
Published: June 2011

The exceptional Lie groups playa significant role in elementary particle models involving octonionic coloured quark fields. Simple methods for calculating the basic properties of these groups are outlined here. Among the properties computed are the dimensions and Dynkin index eigenvalues of irreps and branching rules for the most important group-subgroup structures. Kronecker products and symmetrized Kronecker powers of irreps of the exceptional groups are resolved. The concepts of elementary multiplets and Schur functions (S-functions) are used to greatly simplify the calculations, making possible manual calculations that are well beyond the capabilities of modem computer algorithms based on the enumeration of weights.
Ligand Ordering Parameters
Authors: Newman DJ
Published: June 2011

Lanthanide and actinide single-ligand crystal field parameters are shown to define similar spectrochemical series to the cubic parameter for 3d ions, providing direct evidence that the dominant electronic processes which cause crystal field splittings are the same for all open-shell ions. The contrast between the nephelauxetic series and the spectrochemical series and the existence of a strong empirical correlation between the former and ligand polarizability show that the nephelauxetic series cannot be determined by the admixture of ligand and open-shell wavefunctions as is often assumed. The influence of ligand polarizability on various spectroscopic parameters is then discussed.
Properties of 2:2 Chalcogenide Crystals with Sodium Chloride Structure
Authors: Thakur KP
Published: June 2011

Values of the compressibility, cohesive energy, atomization energy, force constant, i.r. absorption frequency, Debye temperature, Griineisen parameter, Anderson-Griineisen parameter and MoelwynHughes parameter for 45 chalcogenide crystals with sodium chloride structure are reported here. These have been obtained using a logarithmic interaction potential energy function. A new method of calculation, derived on the basis of the Moelwyn-Hughes parameter, has been employed for the computation of the potential parameters, since previous methods cannot be applied to these crystals in the absence of compressibility data. The results obtained are encouraging.
The Effect of Plate Oscillations on Horizontal Free Convection Flow
Authors: Verma RL , Singh Punyatma
Published: June 2011

The free convection flow along a semi-infinite horizontal plate oscillating in its own plane is analysed The basic flow is purely buoyancy induced, while the oscillations in the plate cause a time-dependent boundary layer flow and heat transfer. The boundary layer equations are linearized and the first two approximations are considered. Two separate solutions valid for high and low frequency ranges are obtained by a series expansion in terms of frequency parameters. The skin friction and the rate of heat transfer are studied for both frequency ranges. For very high frequencies, the oscillatory flow pattern is of a 'shear-wave' type, unaffected by the mean flow. It is found that the phase of the skin friction at the plate lags that of the plate oscillations by in and the rate of heat transfer has a phase lag of 1/2n.
Surface Waves in Viscoelastic Media Under the Influence of Gravity
Authors: Bhattacharyya S , De SN
Published: June 2011

In this paper formulae are derived for surface waves in a viscoelastic medium of Voigt type under the influence of gravity. The wave velocity equations are deduced from Biot's theory of stress by assuming that the effects of gravity are equivalent to a type of initial stress of a hydrostatic nature. The resulting equations are used to briefly investigate the particular surface waves of Rayleigh, Love and Stoneley type. In all cases the final results are in agreement with the corresponding classical results when the effects of gravity and viscosity are neglected.
Local and Nonlocal Potentials for Low Energy Pion-Nucleon Scattering
Authors: Clayton E , Cook JL , Rose EK
Published: June 2011

Local and nonlocal potentials have been evaluated using the reaction matrix approach to the inverse scattering problem for low energy pion-nucleon scattering. The nonlocal potential gave the oorrect position for the Pll ground state nucleon mass, but the local potential did not. Incident pion energies up to 700 MeV were considered.
Radiative Detection of Single-pulse and Spin-echo Nuclear Magnetic Resonance
Authors: Wilson GVH , Chaplin DH , Cooke P , Foster HR , Lynam P
Published: June 2011

The radiative detection of n.m.r. in thermally oriented radioactive nuclei by observing the effects of a resonant RF field on the anisotropic angular distribution of the ')I-ray radiations was first suggested by Bloembergen and Temmer (1953). The main advantage of radiative detection over conventional n.m.r. techniques, which detect the EMF induced in an RF coil by the precessing nuclei, would be that far fewer nuclei are required. Furthermore, such experiments should lead to new information on the fundamentals of the influence of resonant fields on the emission of radiations by nuclei (Shirley 1968). Thus, following the suggestion of Bloembergen and Temmer, several unpublished attempts were made to detect n.m.r. in nuclei that were oriented in paramagnetic dielectric materials at low temperatures. These attempts failed, probably because of the combination of nonresonant RF heating and the low thermal conductivity of the host materials. More recently, it has been realized that ferromagnetic metals offer significant advantages as host materials, e.g. large hyperfine magnetic fields generally act on the nuclei, the thermal conductivity is relatively high and, relative to the applied RF fields, there is a large ferromagnetic enhancement (Portis and Gossard 1960) of the RF fields which act on the nuclei.
Solar Zenith Angle Dependence of Sudden Cosmic Noise Absorptions
Authors: Sarma SBSS , Sharma MC
Published: June 2011

The zenith angle dependence of the flare-time absorption of SCNAs-(sudden cosmic noise absorptions) is investigated experimentally using riometer data at five widely spaced stations. A cos� X dependence is found with n = 1�4�O�04.