bluuebunny/crossref_metadata_2025 huggingface dataset:
ON THE PRODUCTION OF Be7 IN THE NRX REACTOR BY THE B10(p,α)Be7, Li7(p,n)Be7, AND Li6(d,n)Be7 REACTIONS
Authors: Roy J. C. , Hawton J. J. , Bresesti M.
Published: April 2011

Beryllium-7 has been produced in the NRX reactor by the following reactions: B10(p,α)Be7, Li7(p,n)Be7, and Li6(d,n)Be7. The Be7 has been identified by its half-life and gamma-ray energy. The (p,α), (p,n), and (d,n) reactions were initiated by protons and deuterons produced by neutron – hydrogen atom collisions and by neutron – deuterium atom collisions from the irradiation of boric acid, lithium hydroxide, and lithium deuteroxide respectively. The same three reactions were also initiated by protons and deuterons produced by (n,p) and (n,d) reactions on boron, lithium, and other target elements chemically combined with lithium.
DECAY OF Au196m
Authors: Kavanagh T. M.
Published: April 2011

The isomeric state in Au196 decays to the ground state with an initial M4 transition of energy 175.5 ± 0.5 kev, followed by 148.2 ± 0.5 kev and 188.8 ± 0.5 kev transitions in cascade; a transition of 85.0 ± 0.5 kev is probably also in cascade with these transitions. There is evidence of a weak 135.9 ± 0.5 kev transition converted in Pt, indicating a small electron capture branch in the decay. The half-life of the isomeric state is 9.5 ± 0.3 hours.
FABRICATION ET ÉTUDE DES PROPRIÉTÉS DES ÉMULSIONS IONOGRAPHIQUES
Authors: Fournaux Jean , Demers Joseph , Demers Pierre
Published: April 2011

not available
A FABRY-PEROT SPECTROMETER FOR AURORAL AND AIRGLOW OBSERVATIONS
Authors: Shepherd G. G.
Published: April 2011

A 1-in. Fabry-Perot interferometric spectrometer employing mechanical scanning has been constructed to operate at low order. Such an instrument gives a resolution similar to that of a grating spectrometer but has, at that resolution, a much higher light gathering power. The spectrometer is capable of resolving the sodium D lines in the twilight airglow, scanning once per minute. Some preliminary results on the variation of D2/D1 ratio during twilight are presented. This type of spectrometer should be useful for a number of other applications.
SCATTERING BY A NARROW UNIDIRECTIONALLY CONDUCTING INFINITE STRIP
Authors: Seshadri S. R.
Published: April 2011

The scattering of a plane electromagnetic wave of wave number k by a uni-directionally conducting infinite strip of width 2a is investigated, The problem is formulated in terms of an integral equation whose solution is obtained by a well-known procedure in the form of a series in powers of ka. Expressions for the far-zone fields and the first two terms in the series for the total scattering cross section are obtained.
SCALAR DIFFRACTION BY A PROLATE SPHEROID AT LOW FREQUENCIES
Authors: Senior T. B. A.
Published: April 2011

For the scalar problem of the diffraction of a plane wave by a prolate spheroid the exact solution is known, and by expanding this in ascending powers of ka, where k is the wave number and 2a is the interfocal distance, the Rayleigh series for both the "soft" and "hard" bodies are obtained up to and including terms in (ka)6. The corresponding results for an oblate spheroid can be deduced by a trivial change of parameters. Some particular cases are examined.
THE HYDROGEN ION EFFECT IN WHISTLER DISPERSION
Authors: Barrington R. E. , Nishizaki T.
Published: April 2011

Four low-altitude whistlers have been carefully analyzed by a specially developed filtering technique. In each case the low-frequency portions of the resulting dispersion curves show similar departures from the simple [Formula: see text] law developed by Eckersley. The departures are found to be of the form and magnitude predicted by Storey on the assumption that the propagation is partly supported by the light hydrogen ions of the exosphere. If it is assumed that the observed deviations are due only to hydrogen ions, and that above some transitional level the positive ions are mostly hydrogen, an estimate of 1000 km for the height of the transitional level is obtained.
A SOLUTION OF THE EINSTEIN FIELD EQUATIONS
Authors: Rastall Peter
Published: April 2011

An exact, cylindrically symmetric, time-dependent solution of the Einstein gravitational field equations for empty space is derived. A particular case of the solution has singularities only on the axis of symmetry and may represent a number of particles in an otherwise empty universe.
NUCLEAR ORIENTATION IN ANTIFERROMAGNETIC SINGLE CRYSTALS
Authors: Daniels J. M. , Giles J. C. , LeBlanc M. A. R.
Published: April 2011

Mn54 and Co60 have been successfully oriented in five antiferromagnetic single crystals (MnCl2∙4H2O, MnBr2∙4H2O, CoCl2∙6H2O, Co(NH4)2(SO4)2∙ 6H2O, and MnSiF6∙6H2O) and the orientation was detected by the anisotropy of the emitted γ rays. Only in the case of Co60 in MnBr2∙4H2O was no γ-ray anisotropy seen. It is concluded that antiferromagnetism can be used as a means of producing nuclear orientation. Attempts to orient Br82 and 1131 in the manganese halides by superexchange were unsuccessful.
TURBULENT DIFFUSION IN TWO AND THREE DIMENSIONS BY THE RANDOM-WALK MODEL WITH MEMORY
Authors: Bourret R. C.
Published: April 2011

A lattice model used for the derivation of the telegraph equation for diffusion is extended to two and three dimensions. Appropriate generalizations of the telegraph equation are obtained. These equations give a fine-grained chronological description of diffusion. From these equations, the velocity autocorrelation functions of the diffusing particles are obtained.
THEORY OF TRANSLATIONAL ABSORPTION IN GASES
Authors: Poll J. D. , Kranendonk J. Van
Published: April 2011

The theory of translational infrared absorption in gases is developed. Invariant expressions for the integrated absorption coefficients are derived. The absorption coefficients are expanded in powers of the density, and the binary absorption coefficients are expressed in terms of a model for the induced pair dipole moments. Monatomic gas mixtures, diatomic gases, and diatomic–monatomic gas mixtures are considered in detail. As an application the binary absorption coefficient of the translational band of hydrogen is calculated.
REFRACTION AND DIFFRACTION OF PULSES
Authors: Williams W. E.
Published: April 2011

It is shown that the solution for the reflection and refraction of a plane pulse at a plane interface may be obtained, by Fourier synthesis, from the corresponding solution for a time-harmonic plane wave even when the angle of incidence is such that total reflection occurs. The application of the Fourier superposition method to problems involving both refraction and diffraction is also discussed.
ON THE PRODUCTION OF Be7, Mg28, AND Ni66 IN THE SLOW NEUTRON FISSION OF U235
Authors: Roy J. C.
Published: April 2011

The yields of 53-day Be7, 21.3-hour Mg28, and 56.6-hour Ni66 from the slow neutron fission of U235 have been investigated. Upper limits of 3 × 10−7% and 4.2 × 10−9% have been set for the fission yields of Be7 and Mg28 respectively. A fission yield of 2.0 ± 1.0 × 10−8% has been found for the formation of Ni66. These results are compared with the current knowledge of the frequency of triple fission of U235.
DIPOLE-FIELD TYPE MAGNETIC DISTURBANCES AND AURORAL ACTIVITIES
Authors: Bhattacharyya B. K.
Published: April 2011

The characteristics of the magnetic field components at Agincourt have been calculated for a current system produced by an electric dipole located in the region of auroral activity near Ottawa. It is noted that, irrespective of the orientation of the dipole, the horizontal magnetic field component rotates in the clockwise and anticlockwise senses for motion of the dipole towards the east and the west respectively, when the dipole is situated in the north half of the sky as seen from the observing station.Next, the magnetograms obtained at Agincourt have been studied at those times of the night when auroral activity was recorded in the all-sky camera photographs at Springhill near Ottawa. It is noted that the horizontal magnetic field describes a loop during a particular phase of auroral activity because of its gradual growth and decay. The distributions of clockwise and anticlockwise rotations with respect to local time are found to be very similar in many respects to those of auroral motions to the east and west respectively. The sense of rotation of the loop is predominantly anticlockwise in the early part of the night and clockwise in the late hours of the night.It is found that eastward and westward orientations of the dipole are the most probable ones. The direction of movement and the initial location of the predominant auroral form in the sky are found to tally well with those of the dipole deduced from a study of the magnetograms.It seems that there is a time sequence relationship between successive phases of auroral activity and changes of characteristics of the loops described by the horizontal magnetic field vector. The area of a loop and the maximum magnitude of the field vector in the loop appear to be related to the brightness and horizontal extent of the auroral forms.
PRODUCTION OF Lu178 BY THE Ta181(n, α)Lu178 REACTION IN THE NRX REACTOR
Authors: Betts R. H. , Glentworth P.
Published: April 2011

A rare earth activity of half-life 19 ± 1 min, produced by irradiating tantalum in the fast neutron flux of the NRX reactor has been shown to be a lutetium nuclide. The 19 ± 1 min activity was ascribed to Lu178 produced by the Ta181 (n, α)Lu178 reaction. Three γ rays of 450 ± 15 kev, 320 ± 15 kev, and 680 ± 15 kev (very weak) are associated with the 19 ± 1 min Lu178 activity.
PHONON DRAG IN LEAD
Authors: Pearson W. B. , Gold A. V.
Published: April 2011

We have carried out measurements on the thermoelectric power of dilute alloys of lead with the solutes Cd, In, Sn, Tl, and Bi in order to test a plausible hypothesis that much of the thermoelectric behavior of pure lead at low temperatures can be ascribed to phonon drag. The results are qualitatively consistent with the phonon-drag picture only if it is assumed that the scattering of phonons by these impurities depends more critically on the valence difference between solvent and solute than on the mass difference.
ROOM TEMPERATURE STABILIZATION OF RADIATION-PRODUCED FREE RADICALS IN BARBITURIC ACIDS
Authors: Cloutier J. A. R.
Published: April 2011

Experimental evidence has shown that a boric acid glass may be used to stabilize at room temperature organic free radicals produced by radiation in a number of barbituric acid derivatives. The method and the experimental results are discussed.
THE HALL EFFECT AND RESISTIVITY OF TELLURIUM
Authors: McKay R. W. , Gravelle W. E.
Published: April 2011

The Hall effect and resistivity of seven crystalline samples of highly purified tellurium were investigated over the temperature range −190 °C to +350 °C. The samples were grown from zone-refined tellurium with an adaptation of the method of Tammann. The effective impurity concentrations were in the range 5 × 10−6 to 5 × 10−5 atomic per cent. The measurements were made with an a-c. method of high sensitivity.X-Ray investigations indicated that the purest sample was a single crystal, but that the others were polycrystalline. However, differences in the observed properties as a result of crystal structure were not large.At high temperatures pure tellurium exhibits an anomalous behavior in its Hall effect, and three proposed explanations of this anomaly were investigated in view of the data of this research. At much lower temperatures, it was concluded that tellurium behaved as a simple semiconductor with unique conduction and valence bands with a non-degenerate carrier distribution.
A POWER SERIES EXPANSION OF THE MASTER EQUATION
Authors: Kampen N. G. van
Published: April 2011

In order to solve the master equation by a systematic approximation method, an expansion in powers of some parameter is needed. The appropriate parameter is the reciprocal size of the system, defined as the ratio of intensive and extensive variables. The lowest approximation yields the phenomenological law for the approach to equilibrium. The next approximation determines the mean square of the fluctuations about the phenomenological behavior. In equilibrium this approximation has the form of a linear Fokker–Planck equation. The higher approximations describe the effect of the non-linearity on the fluctuations, in particular on their spectral density. The method is applied to three examples: density fluctuations, Alkemade's diode, and Rayleigh's piston. The relation to the expansion recently given by Siegel is also discussed.
THE FINITE BEAM SPACE-CHARGE LIMITED DIODE AS A NOISE TRANSDUCER
Authors: McFarlane R. A.
Published: April 2011

A method is presented for calculating the noise properties of a cylindrical electron beam from a space-charge limited diode electron gun. The multivelocity character of the beam is considered and correction is made for finite beam diameter. The ratio of anode noise current to full shot noise is found to depend on ω1/2/V0a where ω is the frequency and V0a the anode voltage.
MODELS OF AURORAL IONIZATION: PART II. APPLICATIONS TO RADIO OBSERVATIONS OF AURORA
Authors: Moorcroft D. R.
Published: April 2011

In this paper the available experimental evidence concerning radio reflections from aurora is examined in relation to the reflection characteristics of the models of auroral ionization discussed in Part I.The existence of critical reflection from auroral ionization at frequencies between 30 and 50 Mc/s appears to be established. This implies electron densities as great as 3 × 1013 electrons/m3. It is shown that the observations are consistent with a model consisting of irregularities of ionization elongated parallel to the earth's magnetic field in a ratio of between 5 and 10 times, and having sizes transverse to the held lines of the order of a few meters. Some of the observations require the irregularities to be distributed in size. It is clear that there is a need for more relevant measurements on radio reflections from aurora to specify the characteristics of the ionization more precisely.
SCATTERING OF RADIO WAVES BY AN IONIZED GAS IN THERMAL EQUILIBRIUM IN THE PRESENCE OF A UNIFORM MAGNETIC FIELD
Authors: Fejer J. A.
Published: April 2011

In an earlier paper (Fejer 1960) a theory was developed for the scattering of radio waves by the electron density fluctuations that exist in an ionized gas in thermal equilibrium. The theory treated only the extreme cases where the "characteristic scale" of the scattering irregularities is either very much larger or very much smaller than the Debye length. The presence of only one type of singly charged ion was considered and the ion and electron temperatures were assumed equal. The effects of an external magnetic field were not taken into account.These earlier limitations are removed in the present paper and the effects of an external magnetic field are taken into account.It is shown that the total power is independent of the magnetic field and an expression for the frequency spectrum of scattered power in the presence of a uniform magnetic field is obtained. Useful approximations to this expression are derived for various limiting cases of interest.It is concluded that the magnetic field need not be taken into account in the interpretation of past observations by Bowles (1958, 1959) and by Pineo, Kraft, and Briscoe (1960). In future experiments, however, particularly at great heights, the effect of the magnetic field could be considerable.
EFFECT OF TWO-DIMENSIONAL MECHANICAL STRESS ON THE DIELECTRIC PROPERTIES OF POLED CERAMIC BARIUM TITANATE AND LEAD ZIRCONATE TITANATE
Authors: Brown R. F.
Published: April 2011

Studies have been made of the dielectric behavior of several ferroelectric ceramic materials when a two-dimensional stress was applied normal to the axis of polarization. It has been shown that the dielectric constant decreases and the dielectric loss increases with increasing stress, part of the change being irreversible and part reversible. Upon application of stress to a sample, the dielectric constant did not change instantaneously but appeared to decrease linearly with the logarithm of time. Mechanisms are suggested for the observed effects.
REPRESENTATIONS OF SPACE GROUPS
Authors: Raghavacharyulu I. V. V.
Published: April 2011

The construction of the irreducible representations of space groups by the little-group method making use of their solvability property is discussed. As an example the two-dimensional space group p4g is considered and all the allowable representations for the groups Gk’s of typical wave vectors k of the group pig are obtained.
THE KNIGHT SHIFT OF CADMIUM IN SOME ALLOYS WITH GROUP IB AND IIB METALS
Authors: Grant R. F. , Henry W. G.
Published: April 2011

The Knight shift of the Cd111 and the Cd113 resonance in the primary solid solutions of silver, gold, magnesium, zinc, and mercury in cadmium has been investigated. The effect of the solute metal on the Knight shift of the solvent is discussed in terms of the charge displacements.
NUCLEAR SPIN RELAXATION IN GASES AND LIQUIDS: I. CORRELATION FUNCTIONS
Authors: Oppenheim Irwin , Bloom Myer
Published: April 2011

Calculation of nuclear spin–lattice relaxation times T1 in liquids and gases involves the correlation functions of the matrix elements between different spin states of the interaction coupling the nuclear spin to other degrees of freedom of the system. The correlation functions are expressed in terms of a time-dependent pair-distribution function (TDPDF) for the system. The TDPDF is evaluated using the Wigner distribution function to describe the equilibrium ensemble of the gas or liquid. A time expansion of the dynamics of the system to a constant acceleration approximation and use of the symmetry properties of the TDPDF leads to an expression of the form[Formula: see text]This form for the TDPDF is derived for the high temperature dilute gas, for the dilute gas with first quantum correction, and for classical liquids in which the molecular dynamics can be described by the Langevin equation. The quantity g(R) is the radial distribution function appropriate to each case. The quantity P(R2, R′2, t) is the free particle TDPDF for the classical gas; it is the classical free particle TDPDF at an effective temperature for the quantum gas; it is the product of solutions to the diffusion equation for the liquid multiplied by the (density)2.
NUCLEAR MAGNETIC RESONANCE MEASUREMENTS IN HYDROGEN GAS
Authors: Lipsicas M. , Bloom M.
Published: April 2011

The proton spin–lattice relaxation time T1 has been measured for H2 gas using pulse techniques over the temperature range 39 °K to 300 °K and at pressures up to 150 atmospheres. T1 is proportional to density, ρ, at low densities and constant temperature, over the entire temperature range studied. Deviations from linearity due to three-body collisions are observed at densities of the order of 500 Amagats. T1/ρ for the dilute gas is approximately constant from about 100 °K to 300 °K but increases sharply at lower temperatures. The spin–spin relaxation time T2 was measured at 78 °K and found to be proportional to ρ but shorter than T1. The diffusion constant D was measured, using the properties of the spin echo, at 78 °K in the dilute gas. Dρ was found to be constant. An analysis of the temperature dependence of T1/ρ using the theory of Needler and Opechowski shows that the excited rotational states of ortho-H2 probably play no role in the spin–lattice relaxation below 300 °K. The T1 results are interpreted in terms of the theory of Oppenheim and Bloom to give information on the anisotropic H2–H2 interactions. The constancy of T1/ρ at high temperatures cannot be understood in terms of the classical properties of the gas. Quantum mechanical diffraction effects play an extremely important role in the spin–lattice relaxation even at high temperatures because of the very short range nature of the anisotropic interactions.
THE SPECTRUM OF NEUTRONS FROM THE IRRADIATION OF URANIUM BY 14-MEV NEUTRONS
Authors: Clarke R. L.
Published: April 2011

The spectrum and absolute yield of neutrons resulting from 14-Mev neutrons incident on natural uranium was observed at 90°± 16 to the incident neutron beam by a time-of-flight method. Further observations of the spectrum from 9 to 13.5 Mev were made for scattering angles at 30° and 60°. In addition to the expected neutrons resulting from evaporation and fission, strong evidence is seen for direct interaction inelastic scattering. The (n,n′) cross section is estimated to be 150 ± 70 millibarns.
NEUTRON EVAPORATION IN THE 14-MEV NEUTRON FISSION OF URANIUM
Authors: Hanna G. C. , Clarke R. L.
Published: April 2011

The numbers of prefission and postfission neutrons expected from the 14-Mev neutron fission of uranium have been calculated from the experimental data on partial cross sections and neutron multiplicities. It has been assumed that the competition between neutron emission and fission does not change with increasing energy beyond threshold. The neutron energy spectrum measured recently by Clarke gives a smaller intensity in the energy range 4–6 Mev than is expected from the calculated number of postfission neutrons. The measured intensity suggests that only 2.1 ± 0.5 neutrons are evaporated from the moving fission fragments.
THE ELECTROMAGNETIC FIELDS OF A HORIZONTAL DIPOLE IN THE PRESENCE OF A CONDUCTING HALF-SPACE
Authors: Wait James R.
Published: April 2011

The problem considered is a horizontal electric dipole which is located above or below the plane surface of a conducting half-space. Expressions for the fields are obtained using three different approaches. The formulas developed are quite simple and, taken together, the whole range of distances from the far-zone to the near-zone is adequately covered.
THE K–LL AUGER SPECTRUM OF 66Dy161
Authors: Graham Robert L. , Merritt Janet S.
Published: April 2011

The K–LL Auger spectrum of 66Dy161 has been studied using the Chalk River iron-free β-ray spectrometer at an instrumental resolution of ~0.07%. After correcting for the estimated intensity of the L3 43.81-kev conversion line (96% M1 + 4% E2), which coincides with the second (K–L1L2) Auger line, the following energies and intensities are obtained for the seven Auger lines:[Formula: see text]The energies are from 20 to 50 ev higher than the non-relativistic predictions. The relative intensities are consistent with experimental results at other atomic numbers.
A NOTE ON THE DIFFRACTION OF A SCALAR WAVE BY A SMALL CIRCULAR APERTURE
Authors: Hurd R. A.
Published: April 2011

The power series solution for the diffraction of a scalar plane wave incident normally on a small circular aperture in a hard screen is extended to include terms of order α12 in the aperture field, and to terms of order α10 in the transmission coefficient (α = 2π × radius of aperture/wavelength). To do this, a set of recurrence relations is developed, and a relatively simple method of obtaining the transmission coefficient is devised.
MESURE DU TEMPS DE RELAXATION D'UNE VIBRATION DE N2O PAR UNE MÉTHODE INFRAROUGE
Authors: Gauthier Germain , Marcoux Jules
Published: April 2011

not available
ALFVÉN WAVES IN PARTIALLY IONIZED GASES
Authors: Watanabe Tomiya
Published: April 2011

The conditions for a wave, propagated in a partially ionized gas along an external magnetic field, to be of Alfvén type have been obtained.
THE T(α,γ)Li7 REACTION
Authors: Griffiths G. M. , Warren J. B. , Morrow R. A. , Riley P. J.
Published: April 2011

The T(α,γ)Li7 reaction has been observed using thin targets of tritium absorbed in zirconium bombarded by singly charged helium ions of energy from 0.5 Mev to 1.9 Mev. The cross section rises smoothly with energy in a fashion characteristic of a direct radiative capture process. The ratio of the intensities of transitions to the first excited state at 478 kev and to the ground state is 0.40 ± 0.05. The angular distribution is, to within errors, isotropic at Eα = 0.8 Mev but is significantly higher at 0° than at 90° for Eα = 1.6 Mev. The total capture cross section at a mean alpha-particle energy in the target of 1.32 Mev is 3.58 ± 0.60 microbarns and the corresponding astrophysical S factor is 0.064 ± 0.016 kev barn in the center of mass system. The results are compared with recent theoretical results on the direct radiative capture process.
ON THE STATISTICAL PROPERTIES OF OPTICAL AND RADIO AURORA
Authors: Hector F. , Forsyth P. A.
Published: April 2011

The latitudinal variation of certain auroral forms has been investigated by means of all-sky camera records made in central Canada during the I.G.Y. The forms chosen were those that may have significance in theories of auroral morphology. The occurrence of "curl forms" seems to be concentrated near the auroral zone. One type of radio reflection (A2) appears to be associated with the curl forms and another type (A3) with patchy, early morning aurora, which occurs most frequently well south of the auroral zone.
A UNIFYING THEORY OF HIGH-LATITUDE GEOPHYSICAL PHENOMENA AND GEOMAGNETIC STORMS
Authors: Axford W. I. , Hines C. O.
Published: April 2011

This paper is concerned with the occurrence at high latitudes of a large number of geophysical phenomena, including geomagnetic agitation and bay disturbances, aurorae, and various irregular distributions of ionospheric electrons. It shows that these may all be related in a simple way to a single causal agency, namely, a certain convection system in the outer portion of the earth's magnetosphere. The source of this convection is taken to be a viscous-like interaction between the magnetosphere and an assumed solar wind, though other sources of an equivalent nature may also be available. The model is capable of accounting for many aspects of the phenomena concerned, including the morphology of auroral forms and the occurrence of 'spiral' patterns in the loci of maximum intensities of several features. It also bears directly on the steady state of the magnetosphere, and in particular on the production of trapped particles in the outer Van Allen belt. In short, it provides a new basis on which a full understanding of these several phenomena may in time be built.
CHANGES IN THE DIURNAL HOUR OF MAXIMUM OF THE COSMIC-RAY INTENSITY
Authors: Katzman J.
Published: April 2011

The diurnal hour of maximum of the meson component changed progressively at Ottawa, Canada, from 10 hr 44 min to 14 hr 40 min during the period January 1955 to December 1960 while the nucleon component changed from 12 hr 12 min to 15 hr 16 min for the same period. This evidence favors the 22-year cycle in the diurnal hour of maximum that was first suggested by Thambyahpillai and Elliot, for stations within a geomagnetic latitude belt between 58.1° N. and 48.1° S. The diurnal hour of maximum at Churchill changed from 14 hr 40 min to 15 hr 24 min during the period April 1957 to December 1960 for the meson component and from 15 hr 12 min to 15 hr 52 min for the nucleon component. Although the change was for a later hour the indication of a 22-year cycle at Churchill is not impressive. At Resolute the diurnal hour of maximum is dominated by the varying magnetic masses in interplanetary space. It is shown that the anisotropy varies both in magnitude and direction depending on the conditions that exist in the solar system.
UNCHARGED CONDUCTING TOROIDAL RING IN A UNIFORM ELECTRIC FIELD
Authors: Loh S. C.
Published: April 2011

Mathematical expressions for the potential function of an uncharged conducting toroidal ring placed in a uniform electric field are derived and expressed in terms of toroidal functions. Some numerical results were calculated by the IBM 650 computer at the University of Toronto and are included in the present paper. To verify the calculated results, a systematic study of an electrolytic tank was undertaken. It was found that the theoretical calculations agreed well with the experimental results.
THE B10(α,n)N13 AND B10(t,2n)C11 REACTIONS IN A NUCLEAR REACTOR
Authors: Roy J. C. , Hawton J. J.
Published: April 2011

Ten-minute N13 and 20-minute C11 have been produced in the NRX reactor by the following reactions:[Formula: see text]The alpha particles and the tritons were generated by thermal neutron capture in B10 and Li6, respectively. These reactions offer a simple and rapid method of obtaining C11 and N13 in fairly high specific activities. It is estimated that activities of the order of 100 μc of N13 and 1 mc of C11 can be produced in a thermal neutron flux of 6.5 × 1013 n/cm2 sec. Incidental to these studies are some observations on the chemical behavior of N13 and C11 recoil atoms in a few boron compounds.
AN ABSOLUTE THERMAL RADIATION CALORIMETER
Authors: McGuire J. H.
Published: April 2011

To allow the absolute calibration of field and laboratory radiometers in the range 0.1 to 1.5 cal/cm2 sec, a continuous flow radiation calorimeter has been constructed, based on a design originally developed by the British Joint Fire Research Organization. The temperature difference established between a water outlet and an inlet is sensed by a thermistor bridge and the radiation intensity measurement is made in terms of the level of the electrical power, applied to a built-in immersion heater, which is necessary to reproduce the same temperature difference.
HIGHER-ENERGY GAMMA RAYS IN THE DECAY OF NEPTUNIUM-239
Authors: Connor R. D. , MacKenzie D. R.
Published: April 2011

In the decay of neptunium-239 only two γ-rays with energies in excess of 335 kev have been detected. These have energies of 440 ± 10 and 490 ± 10 kev and intensities of 3.6 ± 0.9 × 10−5 and 2.0 ± 0.5 × 10−5 photons per disintegration respectively. A search at high resolution failed to reveal the associated conversion lines in the β-spectrum.
STUDIES IN CHROMATOGRAPHIC TRANSPORT: II. THE EFFECT OF ADSORPTION ISOTHERM SHAPE
Authors: Tudge A. P.
Published: April 2011

When an adsorbate with a complex adsorption isotherm is transported chromatographically, concentration shocks, either stable or unstable, can occur. Methods are given for determining the transport behavior of each type of shock. Mistakes in the literature are corrected.
NORMAL MODES OF VIBRATIONS OF CRYSTALS
Authors: Raghavacharyulu I. V. V.
Published: April 2011

The general theory of the normal modes of vibrations of crystals as given by Max Born and von Karman has been analyzed group theoretically. This is illustrated with reference to the diamond lattice.
COMPRESSIBILITY OF LIQUID He4
Authors: Edwards M. H. , Woodbury W. C.
Published: April 2011

The refractive index n, density ρ, and isothermal compressibility kT = (1/ρ) × (∂ρ/∂P)T of liquid He4 have been measured along isotherms between the saturated vapor pressure and 4.5 atmospheres at 3.0°, 3.5°, 4.0°, 4.5°, and 5.0° K. The liquid was compressed in an optical cell 9.58 cm long in a Jamin interferometer. Changes in density were inferred through the Lorenz–Lorentz equation from refractive index changes measured with a photomultiplier fringe recorder. One fringe corresponds to a change in refractive index of (5.699 ± 0.003) × 10−6 in this apparatus. Densities range between 0.0995 g cm−3 at 5.0° K at the saturated vapor pressure and 0.1501 g cm−3 at 3.0° K and 4.5 atmospheres pressure. Compressibilities range between 65 × 10−8 cm2 dyne−1 at 5.0° K at the saturated vapor pressure and 1.16 × 10−8 cm2 dyne−1 at 3.0° K and 4.5 atmospheres pressure. The limiting liquid structure factors for zero-angle X-ray scattering and for coherent scattering of slow neutrons have been calculated from these density and compressibility measurements. In addition, the ratio of heat capacities has been calculated at 3.0°, 3.5°, and 4.0° K where other measurements of the velocity of first sound are available.
THE AUTOCORRELATION FUNCTION OF SYMMETRICALLY FOLDED GAUSSIAN NOISE
Authors: Shepertycki T. H.
Published: April 2011

Noise with a uniform distribution of amplitudes and frequency of level crossings can be obtained by passing Gaussian noise through a symmetrical folder. A nonlinear device is required to do this. The input–output amplitude characteristic of this device has a positive unity slope between certain voltage (folding) levels which are symmetrical with respect to zero. The characteristic assumes a negative slope, called the folding slope, for voltages above and below the respective folding levels. The autocorrelation function of symmetrically folded noise is calculated. Curves are presented showing the power spectrum of symmetrically folded low-pass Gaussian noise for various degrees of folding and various values of folding slopes.
THE CONCENTRATION DEPENDENCE OF PARAMAGNETIC RELAXATION IN DILUTE POTASSIUM CHROMI- AND FERRI-CYANIDES AT LIQUID HELIUM TEMPERATURE
Authors: Kipling A. L. , Smith P. W. , Vanier J. , Woonton G. A.
Published: April 2011

Measurements of the spin–spin relaxation time and of the effective, lattice-induced, transition probabilities are reported for magnetically dilute potassium chromicyanide in chemically analyzed concentrations ranging from 0.06 to 1.5%. In these measurements the c-axis of the cobalticyanide matrix was parallel to the static magnetic field. All measurements were made at a temperature of 4.2° K. Measurements made at a concentration of 1.5% did not fit into the same pattern as measurements made at lower concentrations, suggesting a change in the dominant mechanism of relaxation. Pulse and saturation measurements have been compared. The effective, lattice-induced transition probability by the pulse method for samples in the lower range of concentration was found to be independent of the concentration and of the transition involved and was found to have a value of[Formula: see text]The results for potassium ferricyanide were much less reliable and only two concentrations, 0.2 and 0.4%, have been examined. The static magnetic field was parallel to the b-axis and the temperature was 4.2° K. The value of W is probably between 1000 and 2000 sec−1.
ROCKET MEASUREMENTS OF AURORAL RADIO ABSORPTION
Authors: Heikkila W. J. , Penstone S. R.
Published: April 2011

Three Black Brant rockets were instrumented by the Radio Physics Laboratory of the Defence Research Board to measure ionospheric radio absorption during ionospheric disturbances. This instrumentation included v.h.f. receivers to measure the strength of cosmic radio noise and of radio signals from the ground during the flight. Geiger counters were provided by the National Research Council of Canada to measure the flux of energetic particles. Results from a flight made at dawn on October 28, 1960, during auroral absorption, indicate that most of the absorption at 22 Mc/s occurred at an altitude between 65 and 90 km, with the most intense absorption occurring in the 70- to 75-km region.This observation is consistent with the observation made by N.R.C. of increasing numbers of electrons with energies greater than 30 kev above about 74 km, both during the ascending and the descending portions of the flight. Assuming large horizontal extent of the absorbing regions, the rocket measurement of 11.5 db of total absorption at 22 Mc/s along an oblique path at 60° from the zenith agrees closely with the 30 Mc/s zenith riometer observation of 3.3 db.
DIRECT MEASUREMENT OF CHARGED PARTICLES ASSOCIATED WITH AURORAL ZONE RADIO ABSORPTION
Authors: McDiarmid I. B. , Rose D. C. , Budzinski E.
Published: April 2011

A rocket experiment to study the charged particles associated with auroral radio absorption is described. A primary electron flux, probably in the form of beams or columns, with a maximum intensity of 2 × 106 particles cm−2 sec−1 was observed. The integral electron energy spectrum could be represented by exp (−E/22 kev) at energies above 30 kev. The angular distribution of the incident electrons was approximately isotropic over the upper hemisphere. Two other types of angular distributions, involving large intensities of upward-moving particles, were observed. The measured electron flux was sufficient to account for the observed radio absorption.Protons in the energy range greater than 500 kev were recorded with a maximum intensity of 6 × 102 particles cm−2 sec−1 sterad−1. The proton intensity was relatively steady and was not correlated with the electron flux either in space or in time. Most of the protons appeared to enter the atmosphere to the south of Fort Churchill.
VARIATIONS WITH HEIGHT AND FORM OF ROTATIONAL TEMPERATURES IN AURORA
Authors: Johanson A. E. , Jones A. Vallance
Published: April 2011

The height variations of [Formula: see text] rotational temperatures in aurora have been measured from the long slit spectra of suitable auroral forms near the northern horizon. The results show a definite increase in temperature with emission height. Under the best observing conditions, temperature gradients of about 6° K/km were found in the 100- to 160-km region. Temperatures were also obtained from different forms and types of aurora using a narrow field of view. The results indicate that type-A red and sunlit auroral forms give higher temperatures more frequently than do more normal types; the former show many temperatures between 700 and 1000° K which correspond to heights in the 200- to 250-km range. When the temperatures obtained were classified according to the form of aurora, it was found that diffuse and pulsating surfaces also show higher temperatures more frequently than do bands and arcs. The temperatures obtained from these forms quite often correspond to heights in the 150- to 190-km range.
THE MICROWAVE SPECTRUM AND MOLECULAR STRUCTURE OF CHF2Cl
Authors: McLay David B. , Mann C. R.
Published: April 2011

Sufficient Q- and R-branch rotational transitions have been measured in the microwave spectrum of the asymmetric top molecule CHF2Cl to determine the moments of inertia Ia, Ib, and Ic for each of the three isotopic species C12HF2Cl35, C12HF2Cl37, and C13HF2Cl35. The value of Ia+Ic−Ib, which should depend only upon the out-of-plane co-ordinate of the fluorine atoms, is sufficiently constant to give a very accurate value for the co-ordinate of 1.08524 ± 0.00006 Å but involves some variations which limit the accuracy of determining molecular structures by isotopic substitutions. The components of the nuclear electric quadrupole coupling dyadics in the principal axes systems for the moments of inertia ellipsoids have been calculated accurately from the hyperfine structure of the C12HF2Cl35,37 spectra. In both cases, eQVaa+eQVbb+eQVcc = 0 and the ratio of any component for Cl35 to the same component for Cl37 is equal to 1.269 within the experimental error. The low-field Stark splitting of the 00,0 → 11,0 transition indicates a dipole moment component μc = 1.5 debyes while the absence of a-type transitions indicates a value for μa, which is less than 0.1 μc. The C—Cl bond length and the angle between this bond and the a-axis have been calculated by Kraitchman's formulae for isotopic substitution to be 1.747 ± 0.002 Å and 14.3 ± 0.2°. This angle and the values of eQVaa, eQVbb, and eQVcc lead to eQVzz = eQq = −71.5 ± 0.3 Mc/s and quadrupole coupling asymmetry parameter η = −0.012 ± 0.006, which indicates very little π-electron character. If the C—H bond length is assumed to be 1.095 ±.015 Å and the angle H—C—Cl is assumed to be 108 ± 1°, then the calculated values for the C—F bond length and for the angle F—C—F are 1.350 ±.003 Å and 107.0 ± 0.4°, a value considerably less than the tetrahedral angle. The values for bond lengths, bond angles, and nuclear electric quadrupole coupling components are compared with those in other halogenated methanes.
LATTICE DYNAMICS OF CALCIUM FLUORIDE: PART I. LYDDANE, SACHS, TELLER FORMULA, DIFFUSE X-RAY SCATTERING, AND SPECIFIC HEAT
Authors: Ganesan S. , Srinivasan R.
Published: April 2011

The reported violation of the Lyddane, Sachs, Teller formula in calcium fluoride has been shown to arise from an error due to the non-application of a symmetry operation in the second neighbor fluorine–fluorine interaction in Cribier's work. By correct deduction of the force constants, the diffuse X-ray scattering measurements are shown to be in accord with the Lyddane, Sachs, Teller formula, but the specific heat calculation on this model is in disagreement with the experimental data.Reflection measurements in the infrared and dispersion of refractive index are shown to be consistent with the principal infrared absorption frequency near 40 μ and not near 51 μ as assumed in the previous model. The calculation of the specific heat using this new infrared frequency agreed with the measurements only at very low and very high temperatures.The two curves are brought into agreement by assuming that the non-Coulomb cross interaction force constant β1 between first neighbor calcium and fluorine decrease with the wave vector. The diffuse X-ray scattering was recalculated on the model, which explained the specific heat data, and was again found to be in agreement with the Lyddane, Sachs, Teller formula. It is suggested that detailed infrared and inelastic neutron scattering studies be made on this crystal.
THERMOELECTRICITY AND ELECTRICAL RESISTIVITY OF DILUTE COPPER ALLOYS OF CHROMIUM, MANGANESE, IRON, AND COBALT AT LOW TEMPERATURES
Authors: Kjekshus A. , Pearson W. B.
Published: April 2011

Low-temperature thermoelectric and electrical resistivity measurements on dilute copper alloys with Cr, Mn, Fe, or Co are reported and discussed, particularly in relation to similar measurements on gold alloys. Both thermoelectric and resistivity measurements have been made for the first time on the same alloys. This paper is a sequel to an earlier paper where the thermoelectric power of "pure" copper was analyzed.
SPECULAR ECHOES FROM DENSE METEOR TRAILS
Authors: Brysk Henry
Published: April 2011

The scalar wave equation is solved for scattering of a normally incident wave by a cylindrical Gaussian distribution of electrons. The backscattered intensity is computed for various line densities, as a function of the radius of the Gaussian. The echo intensity for specular backscattering from meteor trails of arbitrary density is thus obtained, including its variation with time.
THE EFFECT OF THE MARTENSITIC TRANSFORMATION IN SODIUM ON THE THERMOELECTRIC POWER
Authors: Adler J. , Woods S. B.
Published: April 2011

When sodium is cooled, its crystal structure partially changes by martensitic transformation from body-centered cubic to close-packed hexagonal below about 40° K. Reversion does not begin until the temperature is raised above about 45° K, so there is a small temperature range in which sodium may consist of either pure body-centered cubic or mixed phases. Using results obtained by Dugdale and Gugan, it is possible to estimate the amount of hexagonal phase present in the mixed samples from electrical resistance measurements. We have measured the thermoelectric power at 43° K for specimens of body-centered cubic sodium and for partially transformed sodium whose composition was thus known. From these measurements the thermoelectric power of pure hexagonal sodium is estimated to be 10% smaller than that of cubic sodium at 43° K. The distribution of the phases in the partially transformed material is represented by two different models and this result is found to be insensitive to which is used. A brief description of the experimental apparatus is given and some theoretical implications of the results are considered.
STUDIES IN CHROMATOGRAPHIC TRANSPORT: III. CHROMATHERMOGRAPHY
Authors: Tudge A. P.
Published: April 2011

A compilation is given of the many Soviet publications on chromathermography (regular displacement chromatography plus a moving thermal gradient). However, the Soviet workers have failed to describe adequately the transport of adsorbates having Langmuir isotherms. The author corrects this situation with a simple but accurate theoretical treatment. It was found (in contrast to isothermal chromatography) that the relative velocity of transport in the trailing edge of a band obeyed the equation[Formula: see text]The characteristic temperature and/or spread of an adsorbate band depend on (1) the temperature distribution within the gradient; (2) the relative velocity of the gradient; (3) the adsorption isotherm as a function of temperature; (4) the amount of adsorbate; (5) the nature of the carrier solvent; (6) the presence, the amounts, and the isotherms of other adsorbates.Whereas most forms of chromatography dissipate the adsorbate and reduce its concentration, chromathermography provides a mechanism for concentrating the adsorbate to a level that can be above the concentration at which it is injected into the column.
A 4Σ−–2Π TRANSITION OF THE SiF MOLECULE
Authors: Verma R. D.
Published: April 2011

The η bands of SiF, in the region 3300–3400 Å, have been photographed in emission at high resolution. A detailed rotational analysis has shown that these bands represent a 4Σ−–2Πτ transition. The lower state is the ground state of the molecule. The principal rotational constants of the upper and lower electronic states in cm−1 are as follows:[Formula: see text]A discussion of the electron configurations is also given.
A NEW METHOD FOR THE REDUCTION OF ALPHA-RAY BACKGROUND IN A GRIDDED IONIZATION CHAMBER
Authors: Doke Tadayoshi
Published: April 2011

By making use of grid pulses in a double-gridded ionization chamber, it was attempted to eliminate the background pulses caused by the alpha particles emitted from electrodes other than the cathode. Operating conditions for the reductions of the background in this method were investigated analytically. Using the double-gridded chamber of a parallel-plate type with a maximum sample area of 80 cm2 for alpha particles of 9 Mev, a background counting rate of one count per hour was achieved in the energy region from 3.5 to 9 Mev. It was found that an insulator like polyethylene could be used as a sample base with a good resolution for very weak activity. Spectra of weak alpha activities were measured by the present method. For the purpose of practical applications, the construction of a cylindrical double-gridded chamber is proposed.
THE ELASTIC SCATTERING OF Co60 γ-RAYS
Authors: Standing K. G. , Jovanovich J. V.
Published: April 2011

Cross sections have been measured for 90° elastic scattering of Co60 γ-rays (1.33 and 1.17 Mev) from aluminum, copper, and tin. They agree with theoretical predictions for Rayleigh and nuclear Thomson scattering. A continuum between the Compton and the elastically scattered γ-rays interfered with the measurements for heavier elements, since it increased rapidly with Z.The continuum was investigated by observing the γ-rays scattered through 60° by thin gold foils. It was found to be produced directly by the γ-rays themselves, not by the electrons they knock out of the target atoms. The experimental cross section was compared with that expected for incoherent scattering from the bound atomic electrons. It agrees within a factor of 2 with the cross section given by the form factor approximation, although it is more than an order of magnitude larger than a modification of the form factor, which is based on comparison with elastic scattering calculations.The spectrum of elastically scattered γ-rays from lead was examined by a special method in order to reduce the contribution of the inelastic continuum; two photomultipliers faced a single scintillator and pulses from one photomultiplier were counted only when they corresponded to the largest pulses from the other. The cross section between 12° and 150° was found to be much lower than that of most previous measurements. It agrees with the calculated cross section for Rayleigh and nuclear Thomson scattering within the possible errors in the calculations. Therefore the measurements yield no evidence for the presence of Delbrück scattering, the upper limit on its intensity now being set primarily by the uncertainties in the theory.