bluuebunny/crossref_metadata_2025 huggingface dataset:
The WKB Method for a Complex Potential
Authors: Mohr CBO
Published: May 2011

The extension of the WKB method to a complex potential, as used in the optical "model of the nucleus, is discussed. The formula for the complex phase shifts is formally deduced, and its accuracy tested against exact calculations for a square potential well and a well with sloping sides. At low energies there occur large discrepancies; the WKB phases vary regularly with energy, whereas the exact values oscillate violently about the WKB values in a characteristic way and marked resonances occur. The factors affecting the accuracy of the method are discussed.
Free Path Formulae for the Coefficient of Diffusion and Velocity of Drift of Electrons in Gases
Authors: Huxley LGH
Published: May 2011

Free path methods are used to derive formulae for the coefficient of diffusion and the drift velocity of electrons in weakly ionized gases in the general case in which the collisional cross section is a function of the speed of an electron and the law of scattering of electrons in single collisions with molecules is not restricted to a few specific cases. It is found that the results are, in effect, the same as those derived by means of the methods of Maxwell and Boltzmann.
Seismological and Related Aspects of the 1954 Hydrogen Bomb Explosions
Authors: Burke-Gaffney TN , Bullen KE
Published: May 2011

Seismic data, recorded in the regular way, from four American hydrogen bomb explosions of 1954, indicate that the origin-times of the explosions were, in G.M,T. : (i) Feb. 28 days 18 hr 45 min 0 sec, (ii) Mar. 26 days 18 hr 30 min 0 sec, (iii) Apr. 25 days 18 hr 10 min 0 sec, (iv) May 4 days 18 hr 10 min 0 sec. If these surmised times are correct, and if the assumed source-point is correct, the results show that the seismic travel-times from Bikini in all azimuths need reductions of the order of 1?2 sec (possibly more) from the standard travel-times.
Galactic Absorption of 19·7 Mc/s Radiation
Authors: Shain CA
Published: May 2011

Observations have been made of galactic radiation at a frequency of 19�7 Mc/s .using an aerial having a beamwidth 1�� 4. The effect of an absobing band of H II regions around the galactic equator is clearly seen. Isolated H II regions, some very faint, have been detected in absorption. A detailed study of the sky near the galactic centre shows that the source Sagittarius-A is observed in absorption at 19�7 Mc/s.
Ionospheric Demodulation of Radio Waves at Vertical Incidence
Authors: Aitchison GJ
Published: May 2011

In a previous communication, Aitchison and Goodwin (1955) have described an investigation carried out at the University of Adelaide on the demodulation of radio waves at vertical incidence. At a frequency of 1550 kc/s, which is close to the local gyro frequency of approximately 1600 kc/s at the height of the E layer of the ionosphere, marked reductions in the modulation depth were observed on the sky wave. The experimental results tabulated in the previous communication suggested that the effect was greatest at a modulation frequency of the order of 800-1500 cis. From subsequent measurements it is apparent that, in the case of F-Iayer reflection the demodulation was greatest at a modulation frequency of, very approximately, 1 kc/s; in the case of E-Iayer reflection, the degree of demodulation did not vary markedly with change of modulation frequency.
The Clock Paradox and the General Theory of Relativity
Authors: Isaak GR
Published: May 2011

The clock paradox (Dingle 1956; McCrea 1956) which arises when the Special Theory of Relativity is applied to the problem of two identical clocks having different histories in the space time diagram is resolved by the General Theory of Relativity (G.T.R.) (Tolman 1934).
Angular Distribution of a?Particles from 7Li(d, a)5He
Authors: Riviere AC , Treacy PB
Published: May 2011

The deuteron bombardment of 7Li can result in the production of two a-particles and a neutron by one of the following processes: .
Radiative Transfer in Discontinuous Media
Authors: Giovanelli RG
Published: May 2011

The theory of radiative transfer is applied to a scattering and absorbing medium consisting of randomly distributed spherical regions of uniform extinction and scattering coefficients x and s, separated by free space.
The Resolution of the Clock Paradox
Authors: Builder G
Published: May 2011

It is shown that the so-called "clock paradox" can be resolved completely in terms of the restricted theory of relativity. Properly applied, the theory gives a unique and unambiguous value for the relative retardation of two clocks. The seeming paradox can, and does, arise only through using the "rate" of a moving clock without due regard to the exact significance of the quantity so described.
Neutrons from Deuteron Bombardment of Boron
Authors: Bird JR , Spear RH
Published: May 2011

A natural boron target has been bombarded by 920 keV deuterons, and the emitted neutrons detected using nuclear emulsions. A new procedure for analysing measurements is described ; this procedure allows approximate corrections for errors in geometry in the plane of the emulsions. The dependence of resolution on various experimental factors has been studied, and the resolution achieved is indiCated by peak widths of 245 � 25keV and 360 � 50 keV at neutron energies of 9�7 MeV and 13�9 MeV respectively. The angular distributions of the neutrons from the 10B(d,n)l1C reaction corresponding to the ground state of 11C, and the neutrons from the 11B(d,n)12C reaction corresponding to the 7�66 Me V state in 12C, have been determined; both distributions may be attributed to compound nucleus formation. A search has been made for a neutron group corresponding to an excited state at about 5�5 MeV in 12C suggested by Glassgold and Galonsky (1956) on the basis of the a-particle model. An upper limit for the intensity of any such group is set at 1 per cent. of the intensity of the group corresponding to the first excited state in 12C.
Hyperfine Structure in the Microwave Spectrum of Water
Authors: Posener DW
Published: May 2011

Measurement of hyperfine structure in the microwave spectrum of D2O gives (eqQ)OD= + 353 � 4 kc/s for the quadrupole coupling constant of the deuteron in the direction of the OD bond, and the corresponding electric field gradient is .
A Further Note on Ionospheric Recorders and Sporadic E
Authors: Thomas JA , Brown HE , Cairns GG
Published: May 2011

As a supplement to work reported earlier (Thomas, Svenson, and Brown 1956), in which the receiver gain of a P'f recording equipment was systematically changed from record to record, a similar experiment has been devised in which the power radiated by the transmitting aerial is systematically changed, thus altering the "signal-to-noise" ratio at the receiver. This should and does give results differing from those formerly obtained.
Determination of Photonuclear Cross Sections
Authors: Carver JH , Lokan KH
Published: May 2011

A typical photonuclear experiment is considered in which the ?-ray source is the bremsstrahlung from an electron accelerator. It is assumed that the electrons incident on the radiator have kinetic energy k0 and total energy k0+� (where � is the electron rest energy) so that the bremsstrahlung contains photons of all energies k = k0. The yield A(k0) for some particular photonuclear reaction is measured as a function of the electron energy and the problem is to use the data to determine the cross section s(k) as a function of the photon energy.
Obliquity Effects in Interferometry
Authors: Bruce CF , Thornton BS
Published: May 2011

Bruce (1955) and Thornton (1955) recently gave an analysis of the effects of oblique rays in length interferometers. It was shown that, for a given set of fringes produced in light of wavelength A and with a nominal path difference of 2t between the interfering rays, the fringe displacement due to obliquity depends on the value of a phase factor ? = (pt/?)?2, where ? is an obliquity angle.
A Source of Inaccuracy Encountered When Measuring Drift Velocities of Electrons in Gases by an Electrical Shutter Method
Authors: Crompton RW , IH Hall Barbara , Macklin WC
Published: May 2011

In this paper attention is drawn to the precautions which must be adopted when the drift velocities of very slow electrons are to be measured by an electrical shutter method. While the experimental results (which for convenience were taken in hydrogen) show that quite serious errors may result at very low energies when the experimental conditions are unsuitably chosen, they also show that it is possible to reduce such errors to any required degree by appropriate choice of the parameters l and p. The form of the variation of the measured from the true values is in qualitative agreement with a formula given by R. A. Duncan when discussing diffusion in relation to measurements of this type.
Extranuclear Effects with Fast Recoiling Nuclei
Authors: Treacy PB
Published: May 2011

Experimental results are given on angular distributions in the reaction 19F (p,p' ?) proceeding via the second excited state of 19F, with targets in different physical and chemical states. It is noted that effects of extranuclear interactions in flight, in solid or liquid media, should be negligible. Tentative information is obtained about the fate of recoil nuclei in the solids NaF and CaF2. The interpretation is consistent with some effects observed in a-? angular correlations from 241Am in solid sources.
Ionospheric Drifts at Brisbane
Authors: Burke MJ , Jenkinson IS
Published: May 2011

Examination of fading of signals recorded at closely spaced receivers has been used to measure the velocity of horizontal drifts of ionization in the ionosphere. Systematic observations have been made for a period of 2 years, on a frequency of 2�28 Mc/s.
Relation Between Meteor Showers and the Rainfall of August, September, and October
Authors: Bowen EG
Published: May 2011

The rainfall of approximately 300 stations over the globe during the 3 months August, September, and October show departures from the mean which are similar in character to those previously reported for the months November, December, and January. Peaks in the rainfall curve occur on the average 31 days after meteor showers, in good agreement with the value of 30 days arrived at for November, December, and January.
Lattice Thermal Conductivity of Some Copper Alloys
Authors: Kemp WRG , Klemens PG , Tainsh RJ
Published: May 2011

The thermal and electrical conductivities of three copper-zinc alloys annealed at high temperatures, and of two copper-gold alloys, were measured over a wide range of low temperatures, and their lattice component of thermal conductivity was deduced in the range 2?90 �K. It appears that the high lattice thermal resistance at liquid helium temperatures previously found in copper-zinc alloys is a function of solute content rather than of concentration of conduction electrons and that this resistance can be reduced by high-temperature annealing.
The Association of Solar Radio Bursts of Spectral Type III with Chromospheric Flares
Authors: Loughhead RE , Roberts JA , K McCabe Marie
Published: May 2011

The relationship of radio bursts of spectral type III to solar flares is investigated by comparing simultaneous optical and radio observations. Over 300 flares are examined, 85 per cent. of which are microflares (class 1?). About 20 per cent. of the flares are associated with type III events, while more than 60 per cent. of the bursts recorded occur during the lifetime of a flare. These bursts tend to occur near the beginning of the flare or even to precede it slightly.
Galactic Turbulence and the Origins of Cosmic Rays and the Galactic Magnetic Field
Authors: Piddington JH
Published: May 2011

A new absorption mechanism is discussed in relation to the turbulence of the interstellar gas in the presence of a magnetic field. It is evaluated and compared with ordinary viscous absorption in different types of interstellar gas. Wherever there is a proportion, even though very small, of neutral atoms (helium being most likely) the new mechanism predominates for waves of length comparable with one parsec or more.
The Effect of Remanent Magnetization on Aeromagnetic Interpretation
Authors: Sutton DJ , Mumme WG
Published: May 2011

The interpretation of aeromagnetic maps when the source may be approximated to a point dipole or line of dipoles is considered for the general case in which the dipole moment is not necessarily parallel to the Earth's magnetic field. For the line of dipoles, it is shown that even in this general case the depth and location of the source can be found, and in addition the direction of the component of the dipole moment in a plane normal to the line source may be determined. If the K�nigsberger ratio for the rock constituting the source is large, this is approximately the direction of the remanent magnetization. Such information is important from a palaeomagnetic viewpoint. When the source approximates closely to a point dipole, it is not possible both to locate the source and determine the direction of the dipole moment from an analysis of the aeromagnetic map and the solution of the problem requires further information.
Latitude Variations of Frequency of Occurrence of "Spread-F" Satellite Traces
Authors: McNicol RWE , Bowman GG
Published: May 2011

Night-time "spread-F" satellites, revealed as discrete extra traces of range greater than the main F-region echo on ionograms (h'f records) have been recorded by McNicol, Webster, and Bowman (1956)? as part of the spread-F phenomenon at Brisbane. This report is an investigation of the relative frequency of occurrence of such satellites at different latitudes.
Coupling of Nuclear Spins in Molecules
Authors: Posener DW
Published: May 2011

The theory of quadrupole, magnetic dipole, and dipole-dipole interactions of nuclear spins with molecular rotation is generalized for any number of nuclear spins in any free molecule which has no resultant electronic angular momentum.
The Townsend Ionization Coefficients in Crossed Electric and Magnetic Fields
Authors: Blevin HA , Haydon SC
Published: May 2011

An expression is obtained for the first Townsend ionization coefficient in uniform crossed electric and magnetic fields, and shown to be in better agreement with observation than previous theoretical expressions. The" equivalent pressure" concept for the effect of a transverse magnetic field on this coefficient is shown to be a valid approach to the problem, although the value for the equivalent pressure obtained in this analysis differs from the values given by earlier authors.
High Resolution Cinematography of the Solar Photosphere
Authors: Loughhead RE , Burgess VR
Published: May 2011

A description is given of a new photoheliograph designed for time-lapse cinematography on 35 mm film of any selected portion of a 20 cm solar image. The interval between successive photographs can be varied from 5 to 120 sec. Air-suction devices have been incorporated to suppress bad seeing originating within the telescope. The performance of the telescope is briefly discussed and the advantages of the cinematographic technique indicated. A discussion of the effects of atmospheric seeing is given in order to emphasize the great caution needed in the interpretation of solar photographs.
Gain Measurements of Large Aerials Used in Interferometer and Cross?Type Radio Telescopes
Authors: Little AG
Published: May 2011

A method has been developed for measuring the gain of large interferometer and cross-type radio telescope aerials. Use is made of the strong discrete radio sources, whose intensity need not be known, to allow comparison of the gains of the aerials with that of a standard.
Anomalies in Ionosonde Records Due to Travelling Ionospheric Disturbances
Authors: Heisler LH
Published: May 2011

Anomalies which frequently appear on ionosonde records of the F region during the passage of travelling disturbances are classified into four main types; and the diurnal and seasonal distribution of their occurrence is discussed.
Travelling Ionospheric Disturbances in the F Region
Authors: Munro GH
Published: May 2011

Observations of the horizontal movements of travelling ionospheric disturbances recorded on a single radio frequency from April 1948 to March 1957 are analysed for seasonal and diurnal variations of occurrence and of direction and speed of travel. Recording was mainly in daylight hours but some limited night results are included. The average number of disturbances recorded was six per day over the period. Observing accuracy and significance of the deduced data are discussed. The frequency of occurrence has a diurnal variation with a marked midday maximum and a seasonal variation with minima at the equinoxes.
The 1956 Phoenicid Meteor Shower
Authors: Weiss AA
Published: May 2011

From radio observation of this shower at Adelaide the radiant coordinates are estimated to be 15�2, ?55�3. The radio record was obtained when the Earth was some 6 hr from the centre of the stream. The radio rate of 30/hr measured on an equipment of high sensitivity is much lower than expected from the visual rates of from 20 to 100/hr reported from 1 to 9 hr later.
Low Latitude Reflections from the Aurora Australis
Authors: Seed TJ , Ellyett CD
Published: May 2011

Over the past 10 years, radio reflections from aurorae have been fairly extensively studied in the northern hemisphere (Bullough and Kaiser 1954 ; Booker, Gartlein, and Nichols 1955). The southern auroral zone, however, is so far removed from habitable land that very little information has yet become available on the aurora australis. Visual observations are relatively slight, and radio observations are only now commencing.
Coulomb Wave Functions
Authors: Learner A , Robson BA
Published: May 2011

Coulomb wave functions are required for the solution of many physical problems involving charged particles. Recently, Froberg's (1955) review article has shown the need for a skeleton table of the values corresponding to the higher incident energies now so readily available.
Methods for Numerical Calculations with the Type I Counter
Authors: Guest PG
Published: May 2011

Detailed schemes have been prepared for performing numerical calculations of frequency, expectation, and variance. Tables are given of the deviations of the asymptotic formulae from the exact formulae when the time of observation is small.
The General Relationships Between the Elastic Constants of Isotropic Materials in n Dimensions
Authors: Tschoegl NW
Published: May 2011

The relationships between the elastic constants of homogeneous isotropic materials in n dimension are derived and are shown to depend on n. The maximal value of the generalized Poisson's ratio is 1/(n?1). The n-dimensional formulae reproduce the well-known three-dimensional relations for n=3, while n=2 produces the relations, appropriate for monomolecular films. The correct degeneration is shown for n= 1.
Thermal Structures in the Lowest Layers of the Atmosphere
Authors: Taylor RJ
Published: May 2011

An analysis has been made of a number of records of simultaneous fluctuations of temperature at four heights. The results show that the correlation between temperatures at two heights is greatest when the records are displaced relatively to each other, so that earlier points in the upper record are considered together with later points in the lower, by an amount depending on the mean wind speed difference between the two heights. The correlation increases with height relatively to what would be expected in a locally isotropic turbulence.
The Flare?Surge Event
Authors: Giovanelli RG , K McCabe Marie
Published: May 2011

Studies of flare-surges recorded on low magnification Ha flare patrol films show that dark surges on the disk come directly from flares, the initial direction of motion being almost invariably away from the nearest large sunspot.
Polarization Measurements of the Three Spectral Types of Solar Radio Burst
Authors: Komesaroff M
Published: May 2011

A swept-frequency technique was used for measuring the polarization of solar radio bursts occurring at the beginning of the present sunspot cycle. Of special interest were the results for bursts of spectral type III. Contrary to the inference drawn from earlier work, it was found that many of these bursts are highly polarized. Furthermore, there were strong indications that the polarization is produced at the radiation source and is not imposed by propagation conditions in the overlying media.
Evidence of Echoes in the Solar Corona from a New Type of Radio Burst
Authors: Roberts JA
Published: May 2011

A new spectral type of solar radio burst is described. The bursts contain two elements, the second being a repetition of the first after a delay of sec. In each element the frequency increases with time at a rate of 2?8 Mc/s per sec. The bursts are of very short duration and are confined to the longer metre wavelengths. Occasionally they occur within, and evidently form part of the structure of, a burst of spectral type III.
On the Cylindrical Probe Method of Measuring Thermal Conductivity with Special Reference to Soils. I. Extension of Theory and Discussion of Probe Characteristics
Authors: de Vries DA , Peck AJ
Published: May 2011

The theory of cylindrical probes for measuring thermal conductivity is extended to the case of a probe of finite conductivity containing a line source at its centre. This provides a more realistic approximation to most actual probes than the theory for a probe of infinite conductivity developed by other authors. New experimental results are presented which are in complete agreement with theory It is shown how an estimate can be obtained of the magnitude of a possible thermal contact resistance between the probe and the medium and how its influence on the measured conductivity can be assessed.
Ether and Relativity
Authors: Builder G
Published: May 2011

The relative retardation of clocks, predicted by the restricted theory of relativity, demands our recognition of the causal significance of absolute velocities. This demand is also implied by the relativistic equations of electrodynamics and even by the formulation of the restricted theory itself. The observable effects of absolute accelerations and of absolute velocities must be ascribed to interaction of bodies and physical systems with some absolute inertial system. We have no alternative but to identify this absolute system with the universe. Thus, in the context of physics, absolute motion must be understood to mean motion relative to the universe, and any wider or more abstract interpretation of the "absolute" must be denied.
On the Seismological Aspects of the 1954 Hydrogen Bomb Explosions
Authors: Burke-Gaffney TN , Bullen KE
Published: May 2011

Tentative conclusions previously drawn from an analysis of seismic readings of four 1954 hydrogen bomb explosions are re-examined in the light of source data subsequently released on these explosions. The released data show that the authors' earlier computed origin-times for the four explosions were correct within 0�0, 0�4, 0�7, and 0�1 sec respectively. The re-examination shows that the J.B. P tables. need a correction of ?2�2 � 1�0 sec for surface epicentres in the mid Pacific and recordings at continental stations. It is confirmed that any difference between the P travel-times from Bikini to Australia and Bikini to the United States is not much more than 1/2 sec. The authors' previous inferences on the velocities of air waves from the explosions remain undisturbed. The re-examination confirms the occurrence of diffracted PKP waves in front of the 142� caustic, and confirms that these diffracted waves arrive at times significantly earlier than PKIKP waves.
A Study of "Spread-F" Ionospheric Echoes at Night at Brisbane. IV. Range Spreading
Authors: Webster HC
Published: May 2011

In the course of investigations of satellite echoes from the F region of the ionosphere, it was noted that the F and Es traces recorded at night, on h?t equipment at frequencies well below vertical, are broader than anticipated and tend to change in a characteristic manner as the gain of the receiver is lowered. In this paper, a quantitative explanation of these phenomena is elaborated, based on the postulate of a "rough" ionosphere.
Flare?Puffs as a Cause of Type III Radio Bursts
Authors: Giovanelli RG
Published: May 2011

An analysis has been made of the association of type III solar radio bursts with flares which show sudden bright expansions, or "puffs", Type III bursts occur within �2 min of the times of two-thirds of the puffs; by comparison, they occur during the whole lifetimes of about one-quarter of flares of all types (Loughhead, Roberts, and McCabe 1957). Most if not all puffs are followed by surges, and hence it appears that the same explosion yields two quite different ejections; one, at velocities of the order of one-fifth that of light, is responsible for the burst, and the other, at velocities of the order of 100 km/sec, is the surge.
A Catalogue of Radio Sources Between Declinations +10° and ?20°
Authors: Mills BY , Slee OB , Hill ER
Published: May 2011

A catalogue has been prepared of the radio sources observed between declinations +10� and ?20�, using the Sydney cross-type radio telescope at a wavelength of 3�5 m: a total of 1159 sources is listed in the area of 3�24 steradians. This supersedes an earlier catalogue of Mills and Slee in portion of the area, but the differences between the two are small. A number of new identifications with galaxies are suggested, and an analysis made of the statistics of the source distribution. It is concluded that cosmological effects displayed by the distribution, if present, are small. Possibilities are discussed of separating from this distribution the effects of the instrument, the finite angular sizes, and/or the physical clustering of the sources.
An Investigation of the Strong Radio Sources in Centaurus, Fornax, and Puppis
Authors: Sheridan KV
Published: May 2011

Isophotes of three strong southern radio sources have been prepared from observations at a wavelength of 3�5 m with a 50 min pencil�beam system. The two extragalactic sources Centaurus-A and Fornax-A are found to have extensive coronas very much larger than the size of the associated galaxies. Using optical estimates of distance these two sources are shown to have similar spatial extensions and may be physically similar systems. The third source, Puppis-A, may be the remnants of a galactic supernova of type II.
On the Cylindrical Probe Method of Measuring Thermal Conductivity with Special Reference to Soils. II. Analysis of Moisture Effects
Authors: de Vries DA , Peck AJ
Published: May 2011

Thermal conductivity measurements in unsaturated moist porous media are complicated by the action of gravity on the moisture and by moisture movement caused by temperature gradients. The effects of these factors are discussed for the cylindrical probe method.
Electromagnetic Radiation from Electrons Rotating in an Ionized Medium Under the Action of a Uniform Magnetic Field
Authors: Twiss RQ , Roberts JA
Published: May 2011

A theory is given for the radiation from a fast electron rotating, under the action of an external magnetic field, in an ionized plasma. It is shown that, although the radiation is emitted predominantly in the extraordinary mode, the ordinary mode is also weakly excited, even in the limiting case in which the density of the background plasma is vanishingly small. At the harmonics of the gyro frequency of the fast electron the power radiated in the ordinary mode is a few per cent. of that radiated in the extraordinary mode. This ratio is independent of v0,' the velocity of the fast electron, as long as V0 is sufficiently small compared with c, the velocity of light. However, at the fundamental gyro frequency the power radiated in the ordinary mode is lower by a factor than that radiated in the extraordinary mode and indeed is significantly smaller than that radiated, in either mode, at the third harmonic.
The Soft X-Ray L23 Emission Spectrum of Magnesium from Solid and Evaporated Targets
Authors: Crisp RS
Published: May 2011

Spectroscopic studies in the soft X-ray region of 50?1000 � have used both photographic and photomultiplier detection of the radiation diffracted in the grating spectrograph (see, for example, Tomboulian 1957). The photomultiplier method offers the advantage that it is possible to record the time variation in the intensity of radiation emitted at a particular wavelength as changes proceed in the condition of the target.
Electron Excitation of Collective Nuclear Transitions
Authors: Tassie LJ
Published: May 2011

The inelastic scattering of high energy electrons with excitation of collective nuclear transitions is treated using a simple hydrodynamical model in which the collective nuclear motion is assumed to be irrotational and incompressible. The effects of nuclear compressibility are discussed. Using the Born approximation, scattering form factors are calculated for several charge distributions for electric quadrupole transitions, and the sensitivity of the scattering to the form of the nuclear charge distribution is examined.
The Photodisintegration of Nuclei with Z Between 9 and 30
Authors: Spicer BM
Published: May 2011

It is pointed out that the Danos-Okamoto effect (splitting of the giant resonance for non-spherical nuclei into two components) should be more readily observable in the region 9 = Z = 30 than in the rare earth region where the initial search for the effect has been made. The ratio of the energies of the two components of the split resonance depends on the deformation of the nucleus from spherical shape. Deformations are even larger in this region of atomic number than for the rare earth nuclei, whose intrinsic electric quadrupole moments are large. The predictions of the theory of Danos (1958) are shown to be verified experimentally in five cases. Five other cases where the effect should be observable are discussed.
Excited States of 8Be From the 7Li(d,n)8Be Reaction
Authors: Spear RH
Published: May 2011

The energy spectrum of neutrons from the reaction 7Li(d,n)8 Be at 700 keV bombarding energy has been studied with nuclear emulsions at 0, 75, and 135�. Both resolution and statistics compare favourably with those of previous nuclear emulsion measurements of this spectrum. The results do not confirm the suggestions made by earlier workers that levels at 2�2, 4�1, 5�3, and 7�5 MeV in 8Be participate in the reaction, and support the view that the only excited state below 9 MeV in 8Be is the well-known broad level at 2�9 MeV.
A Pencil-beam Survey of the Galactic Plane at 3·5 m
Authors: Hill ER , Slee OB , Mills BY
Published: May 2011

A survey has been made of the galactic plane region from l = 223� through the galactic centre to l = 13� between b = +40� and ?6� using the 3�5 m wavelength cross-type aerial (beamwidth 50 min of arc) near Sydney. Contour diagrams of brightness temperature have been prepared. The preparation of contours is described in detail, and a detailed discussion of the accuracy of the temperatures is given.
Radio Emission from the Vela?Puppis Region
Authors: Rishbeth H
Published: May 2011

The Vela-Puppis region has been surveyed with Mills Cross radio telescopes, and radio isophotes plotted at two wavelengths. Many discrete sources have been observed. Several H II regions have been detected in emission at 3�5 m and in absorption at 15�2 m; the radiation from such objects is of thermal origin. The outstanding feature of this region is a group of strong non-thermal sources near the galactic equator. These are superimposed on an intense belt of radiation along the equator, and this, too, is certainly non-thermal in origin. Some correlation with galactic structure is suggested.
Radiation Transfer and the Possibility of Negative Absorption in Radio Astronomy
Authors: Twiss RQ
Published: May 2011

Stimulated transitions are relatively enormously more probable at radio than at optical frequencies and it is this which makes it possible for negative absorption to arise at radio wavelengths when the medium will behave like an amplifier to the incident radiation. A necessary condition for the existence of this phenomenon is that the kinetic energy distribution F(?) of the radiating electrons be markedly non-thermal with an appreciable excess of high energy electrons such that �F/�? is positive over a finite range of the kinetic energy ?. However, this condition is not sufficient, since it is shown that an electron gas in which free�free transitions provide the dominant radiation process can never exhibit negative absorption whatever the form of F(?), and it is further necessary that the stimulated transition probability should have a maximum at some finite value of the kinetic energy, the most favourable case occurring when this maximum is a sharp one at the value of ? at which �F/�? has a positive maximum. These conditions can both be met in principle for the cases in which the dominant radiation process is due (a) to Cerenkov effect, (b) to gyro radiation by non-relativistic electrons, (c) to synchrotron-type radiation by highly relativistic electrons, and it is shown that negative absorption can arise in all these cases; the relevance of these results to radio astronomy is discussed briefly.
The Clock Paradox in Special Relativity
Authors: Jeffreys H
Published: May 2011

Dr. G. Builder (1957) has produced a new analysis of this problem, which is criticized by Professor Dingle (1957). I think that both introduce concealed hypotheses, and that the methods of the special theory cannot produce a unique answer.
The Clock Paradox in Relativity
Authors: Fahy EF
Published: May 2011

I have been following with great interest the discussions on the above topic which have been published in several journals. On reading a recent letter to Nature by Professor Herbert Dingle (1957) in reply to a previous letter by Sir Charles Darwin (1957), I noticed that it is feasible to perform astronomical observations which could provide an experimental basis for choosing between the two points of view. In fact, these observations may have already been made.
Zero?Field Masers
Authors: Bogle GS , Symmons HF
Published: May 2011

Solid state three-level masers operating with zero magnetic field are shown to be feasible and to have advantages over magnetic field masers in many applications. The requirements of the working substance are discussed and it is found that compounds of CrH, Fe3+, NiH, and Gd3+ should be suitable.
The Photoneutron Cross Section of 9Be in the Intermediate Energy Range
Authors: Thies HH , Spicer BM , Baglln JEE
Published: May 2011

The photoneutron cross section of DBe has been measured in the region from 6�5 to 18 MeV, using filtered bremsstrahlung radiation from an 18 MeV synchrotron. The integrated cross section is in agreement with an earlier experiment, but increased resolution has shown a more complex shape, with sharp maxima at 1l�25�O�2 and 13� 25 � 0�2 MeV. The significant features of the cross section are discussed and compared with the level scheme as it is known at present.
Dirac Continuum Radial Wave Functions
Authors: Perlman HS , Robson BA
Published: May 2011

Tables of Dirac (Jontinuum radial wave functions for an electron in the Coulomb field of a mercury nucleus (Z =80) are presented for several energies and l's. Approximate methods of interpolation and extrapolation to regions not covered explicitly are indicated.
Theory of the Radio?Echo Meteor Height Distribution in a Non-isothermal Atmosphere
Authors: Weiss AA
Published: May 2011

The theory of the distribution in height of the echoing points of shower meteors and of sporadic meteors belonging to a homogeneous velocity group, is extended to the case of a model atmosphere in which the scale height is a linear function of height. The mean and the r.m.s. deviation from the mean of the height distribution in this atmosphere are obtained in terms of tabulated functions, and the dependence of these parameters upon the scale height gradient is evaluated. Neither parameter varies strongly with the scale height gradient unless the incident meteors include a large proportion of massive particles. Experimental cut-off and the approximations made in the formulation of the theory limit the accuracy with which atmospheric scale height and density can be determined from observed heights of sporadic meteors.
Electron Mobility in Liquid Argon
Authors: Stacey FD
Published: May 2011

Experiments of Williams (1957) showed that the drift velocity of electrons in liquid argon to which an electric field F is applied is essentially independent of F. If the electrons remain free then their motion can be described by kinetic theory, from which it appears that electron mobility is proportional to F-I and drift velocity to Fli. This is the dependence reported by Malkin and Schultz (1951), but it is evident that the recent, more exhaustive work of Williams (1957) is correct on this point and therefore that kinetic theory is not applicable to the problem. This theory could in principle be extended to explain a fieldindependent velocity, by supposing a special dependence upon electron energy of the scattering cross section for the collision of electrons with argon atoms, but this is very artificial and unnecessary in view of the alternative explanation suggested here; in any case it leaves further serious objections, which will also be discussed briefly.
The Microwave Spectra of Isotopic Molecules of Sulphur Dioxide
Authors: Smith WE
Published: May 2011

Some new lines in the spectra of 34802 and 33802 have been measured and accounted for in terms of a semi-rigid rotor model with centrifugal distortion coefficients derived from Kivelson's (1954) published figures for 32802, and rotational constants obtained from the measurements.
The Temporal Variation of the Heights of Reflection Points of Meteor Trails
Authors: Weiss AA
Published: May 2011

Heights of reflection points of over 6000 sporadic meteors measured with a 27 McJs combined C.W.�radar equipment are analysed. There is no significant seasonal variation in either the mean height or the width of the height distribution.
Neutral Hydrogen Gas in the Taurus?Orion Region Observed with a Multichannel 21 cm Line Receiver
Authors: McGee RX , Murray JD
Published: May 2011

A multichannel 21 cm hydrogen line receiver has been developed which is capable of producing a complete line profile in the very short time of 2 min.
Occultations of the Crab Nebula by the Solar Corona in June 1957 and 1958
Authors: Slee OB
Published: May 2011

A description is given of some observations of the occultations of the Crab nebula by the solar corona in June 1957 and 1958, obtained with pencil-beam, fan-beam, and interferometer-type instruments. It is shown that the distribution of 85� 5 Mc/s radiation on days when the angular separation is less than 10 solar radii is not consistent with a symmetrical scattering process. Better agreement is obtained by postulating the existence of scattering and regular refraction of comparable magnitude. Certain unexplained features of the pencil-beam distributions indicate that large-scale electron irregularities may be important in the scattering and refraction process. Additional evidence is presented for very short-term changes in the transmission properties of the corona.
A Discussion of Ionospheric Demodulation Near Gyro Frequency
Authors: Goodwin GL
Published: May 2011

Observations made in Adelaide of the ionospheric demodulation of radio waves near gyro frequency at vertical incidence are discussed. The effect occurs in the region of about 90 km, and does not appear to decrease through dawn. An F-Iayer reflected wave is demodulated by unequal amounts during its two passages through the region. The large magnitude of the effect and its lack of dependence on modulation frequency seem to be inconsistent with the theory of wave interaction.
The Structure of a Stream of Electrons and Ions Drifting and Diffusing in a Gas When Ionization by Collision and Molecular Attachment are Present
Authors: Huxley LGH
Published: May 2011

The theory is developed of the structure of a stream of electrons and ions drifting under the action of a uniform field and diffusing in a gas when either or both ionization by collision and electron attachment are present. The cases considered include a point source and a line source, and in the latter case the influence of a magnetic field is discussed.
The Shape of Spectral Lines: Tables of the Voigt Profile
Authors: Posener DW
Published: May 2011

A brief discussion is given of some methods of computing the line shape, commonly known as the Voigt profile, resulting when a spectral line is broadened simultaneously by Gaussian and Lorentz effects, and tables and curves are presented for representative values of the variables.
Photometric Observations of Subvisual Red Auroral Arcs at Middle Latitudes
Authors: Duncan RA
Published: May 2011

A photometer (Roach et aT. 1958) sensitive to the red oxygen emission at 6300 A has been in operation at Oamden, near Sydney (geomagnetic latitude 42�), since July 1958. In this period three bright aurorae have been seen in southern Australia; on July 8-9, September 4-5, and September 25-26. Following the first two the photometer detected a subvisual stable red arc the next night. On the night after the third aurora, observation was prevented by cloud.
The Use of Complete Temperature?Time Curves for Determination of Thermal Conductivity with Particular Reference to Rocks
Authors: Jaeger JC
Published: May 2011

Most of the transient methods at present in use for the determination of thermal conductivity involve the study of the asymptote of a temperature-time curve. This implies that they require relatively long times of experiment and make no use of the information contained in measurements of temperature at smaller times.
A Search for Levels of 7Li Between 9·0 and 9·55 MeV Excitation
Authors: Purser KH
Published: May 2011

The cross section of the reaction 6Li(n,3H)'He has been measured, with good energy resolution, over the neutron range 2�0--2�65 MeV. This corresponds to an excitation of 7Li from 9� 0 to 9� 55 MeV, a region in which photodisintegration experiments indicate the presence of one or more levels. No resonance structure was observed in this experiment and possible reasons for this are discussed.
A 21 cm Survey of the Southern Milky Way
Authors: Kerr PJ , Hindman JV , Gum CS
Published: May 2011

A study has been made of 21 cm hydrogen-line radiation around the Southern Milky Way, using a beamwidth of 1�.4 and a bandwidth of 40 kc/s (8�5 km/sec).
The Lorentz Transformations
Authors: Builder G
Published: May 2011

Sir Harold Jeffreys (1958) has asserted that my analysis of the clock paradox (Builder 1957) is based on concealed hypotheses; but the hypotheses to which he refers are ones that he claims are involved in the derivation of the Lorentz transformations and in the currently accepted methods of using them. He holds that the transformations cannot be shown to be unique and he infers that predictions based on them are not necessarily correct and " cannot be right ill any case" when applied to systems that are inertial at the time considered but that have been subject to acceleration at some other time.
Drift of a Charged Particle in a Magnetic Field of Constant Gradient
Authors: Seymour PW
Published: May 2011

A simple expression for the drift velocity of a charged particle moving in an inhomo, geneous magnetic field has been obtained by Alfven, who, in his first-order theory, considered the inhomogeneity as a small perturbation of a uniform field,
Radio Echo Observations of the Geminid Meteor Stream
Authors: Weiss AA
Published: May 2011

Measurements of radiant coordinates and echo rates from 1952 to 1957 are summarized. A mean radiant of a=113�4�, 3=31�4� at solar longitude 0=260�2�, a small radiant area, and a markedly asymmetrical distribution of meteors across the stream, with a maximum echo rate at 0,=260'8�, all agree with northern hemisphere radio echo observations made between 1949 and 1954.
Solar Radio Bursts of Spectral Type II
Authors: Roberts JA
Published: May 2011

The characteristics of bursts of spectral type II are studied in a sample of 65 bursts. Approximately half the bursts show harmonic structure and about half are compound type III-type II events. Band splitting, the doubling of both the fundamental and second harmonic bands, is also relatively common. A rather less common feature is the appearance of herring-bone structure in which the slowly drifting band of the type II burst appears to be a source from which rapidly drifting elements diverge towards lower and higher frequencies.
Location of the Sources of 19 Mc/s Solar Bursts
Authors: Shain CA , Higgins CS
Published: May 2011

By using large aerials in a new way, it has been possible to locate, with considerable accuracy, the sources of 19 Mcls solar bursts. The positions of these sources have been correlated with the positions of optically active regions associated with them, and the radial distances of the radio sources from the centre of the Sun have been deduced. In 1950-1951, 18�3 Mcls bursts came from sources at a radial distance estimated as 3�4Ro ; more reliable data in 1957 indicated that the sources of 19�7 Mcls bursts were at a radial distance of 2� 9Ro It is thought that these measurements give the distances of the fundamental plasma levels in coronal streamers.
Solar Radio Emission of Spectral Type IV and its Association with Geomagnetic Storms
Authors: McLean DJ
Published: May 2011

A new type of solar radio event, the type IV storm, first described by Boischot, has been identified on Dapto radio.spectrographic records. It has been shown to be distinguishable from type I storms by (i) its smooth spectrum, (ii) its close association with type II bursts, and (iii) its remarkably close association with geomagnetic storms. In common with some type I storms, all type IV storms are found to be associated with very large solar flares.
The Eta Carinae Nebula and Centaurus A Near 1400 Mc/s. II. Physical Discussion of the Eta Carinae Nebula
Authors: Wade CM
Published: May 2011

The 1400 Mcls observations of NGC 3372 described in Paper I (Hindman and Wade 1959) are discussed. Comparison of the flux densities at 85� 5 Mcls (Mills, Little, and Sheridan 1956) and at 1400 Mcls leads to a value of 10,000�1000 OK for the electron temperature of the nebula. Unpublished optical measurements of the distribution of surface brightness across the object, made by Gum, indicate that there is a dense core about 24 min of arc in diameter, surrounded by a much less dense region with a diameter of 120 min of arc.
Towards a Method for the Accurate Solution of the Schrödinger Wave Equation in Many Variables. I. Formulation of the Method for an Eigenvalue Problem without Symmetry Conditions
Authors: Bassett IM
Published: May 2011

The aim of this paper and those following is to formulate and explore a new method, suitable for use with an electronic digital computer, for the solution of eigenvalue. eigenfunction problems in many variables, with the aim of applying the method to the Schrodinger wave equation.
Towards a Method for the Accurate Solution of the Schrödinger Wave Equation in Many Variables. II. A Simple Numerical Illustration
Authors: Bassett IM
Published: May 2011

The method described in Part I is here applied to an eigenvalue problem in two Variables
Towards a Method for the Accurate Solution of the Schrödinger Wave Equation in Many Variables. III. Application of the General Method to the Wave Equation without Spatial Symmetry
Authors: Bassett IM
Published: May 2011

The method of Part I is applied to the problem of finding the lowest antisymmetric eigenfunction of the wave equation for n electrons without spatial symmetry, and the lowest antisymmetric eigenfunction of given multiplicity. Knowledge of the multiplicity of the ground state is not needed. Theorem 3 of Part I, which proves the equivalence of the central stationary condition to a minimum condition, is extended to cover the present case.