bluuebunny/crossref_metadata_2025 huggingface dataset:
THE IEC METHOD AND CONVERSION COEFFICIENTS OF THE 605-keV TRANSITION IN 134Ba
Authors: Zganjar E. F. , Hamilton J. H.
Published: April 2011

Tests of the internal–external method of measuring conversion coefficients in the Vanderbilt double-focusing spectrometer have been made in search of possible errors arising from scattering of photoelectrons in the converter for a photon energy of 605 keV. This scattering may affect the factor, f, which corrects for the anisotropic distribution of the photoelectrons. The 605-keV transition in 134Ba populated by the beta decay of 134Cs was used. An accurate determination of the K, L, and M conversion coefficients of the 2+ to 0+, 605-keV, E2 transition in 134Ba was made. Three uranium converters 1.12, 2.19, and 3.71 mg/cm2 thick were used. The results are compared with the new theoretical calculations of f which depend on the converter thickness and consequently consider the effect of scattering. For photons of energy 605 keV or greater, the IEC method used in the Vanderbilt double-focusing spectrometers is insensitive (< 5%) to scattering in uranium converters < 4 mg/cm2 thick. The K, L, and M conversion coefficients were determined to be (5.03 ± 0.20) × 10−3, (7.07 ± 0.50) × 10−4, and (1.64 ± 0.18) × 10−4, respectively. The respective theoretical values of Rose are 5.08 × 10−3, 6.92 × 10−4, and 2.77 × 10−4. Sliv and Band give a value of 5.10 × 10−3 for the K conversion coefficient.
THE APPROACH TO NUCLEAR STATISTICAL EQUILIBRIUM
Authors: Truran J. W. , Cameron A. G. W. , Gilbert A.
Published: April 2011

The transformation of a region composed initially of 28Si to nuclei in the vicinity of the iron peak, which is thought to take place in the late stages of evolution of some stars, is considered in detail. In order to follow these nuclear transformations, a nuclear reaction network is established providing suitable reaction links connecting neighboring nuclei. A method of solution of the network equations is outlined. Thermonuclear reaction rates for all neutron, proton, and alpha-particle reactions involving the nuclei in this network have been determined from a consideration of the statistical properties of nuclei. The evolution of this silicon region has been followed in time for two cases: T = 3 × 109 °K, ρ = 106 g cm−3 and T = 5 × 109 °K, ρ = 107 g cm−3. While both the observed solar and meteoritic abundances display a broad peak in the vicinity of iron, centered on 56Fe, in these calculations 54Fe is found to be the most abundant isotope in this mass range. Beta decays required to change the peak to 56Fe are very slow. As the transformation 2 28Si → 54Fe + 2p is endothermic by ~1.3 MeV, these results suggest that the silicon-to-iron conversion may not comprise an exothermic nuclear burning stage of stellar evolution.
SOLAR EVOLUTION WITH VARYING G
Authors: Ezer D. , Cameron A. G. W.
Published: April 2011

The model-sequence calculations by the writers of early solar evolution have been extended to the case of a varying-G cosmology. In the varying-G sun there is less lithium depletion than in a constant-G sun, and the time required to burn out central hydrogen is decreased by less than the ratio of luminosities, owing to the much greater total helium production in the varying-G sun. At the present time the varying-G model has four times the 8B neutrino flux of the constant-G model, a prediction that can be subjected to an experimental check.
BEHAVIOR OF THE SCHWARZSCHILD SINGULARITY IN SUPERIMPOSED GRAVITATIONAL FIELDS
Authors: Mysak Lawrence , Szekeres George
Published: April 2011

The effect of superimposed gravitational fields upon the behavior of the Schwarzschild singularity is examined. It is shown that while static disturbances generally have no effect on the nature of the singularity, time-dependent disturbances of an assumed form convert it from a coordinate singularity into a true, coordinate-independent singularity.
SPECTRAL DIFFUSION STUDIES OF THE Cr3+ ION USING ELECTRON SPIN ECHOES
Authors: Dyment John C.
Published: April 2011

Spectral diffusion studies of the Cr3+ ion in the lattices of RbAl(SO4)2∙12H2O (alum) and K3Co(CN)6 (cyanide) have been made, using electron spin-echo techniques. Below 4.2 °K, the nearly temperature-independent behavior suggests that echo attenuation is caused primarily by local field fluctuations due to spin–spin flips. In alum, the nearby nuclear magnetic moments of hydrogen determine the echo attenuation, which is essentially independent of the Cr3+ concentration below 6.7 × 1018 ions/cc. Conversely, in cyanide, the echo attenuation depends strongly on the Cr3+ concentration, which indicates that the diffusion is caused by other Cr3+ moments. However, the Cr3+ decay times were reduced by the addition of Fe3+ ions to the cyanide samples. The results follow a "nearly" Lorentzian diffusion law, as predicted theoretically by Klauder and Anderson (1962). Echo behavior indicates inhomogeneous resonance lines in alum at 1.7 × 1019 Cr3+ ions/cc and in cyanide between 1.5 × 1019 and 4.7 × 1018 Cr3+ ions/cc.
THE SCATTERING FROM ACOUSTICALLY HARD AND SOFT PROLATE SPHEROIDS FOR AXIAL INCIDENCE
Authors: Senior T. B. A.
Published: April 2011

Using a recent comprehensive tabulation of spheroidal functions, the backscattered and surface fields for a variety of prolate spheroids at end-on incidence have been computed, and selected results are presented. In the case of acoustically hard spheroids it would appear that the backscattering is determined primarily by the surface field strengths in the vicinities of the front and rear tips. Some of the consequences of this fact are discussed.
NOUVELLE MÉTHODE TRÈS PRÉCISE D'ÉTALONNAGE DES SPECTRES ENREGISTRÉS À L'AIDE DU SPECTROMÈTRE PHOTOÉLECTRIQUE FABRY-PÉROT
Authors: Gagné Jean-Marie , Helbert J. M. , Gerstenkorn S.
Published: April 2011

not available
DIFFRACTION BY A WIDE APERTURE IN AN ANISOTROPIC MEDIUM
Authors: Jull E. V.
Published: April 2011

Two-dimensional scattering of a plane electromagnetic wave by an aperture in a conducting screen immersed in an anisotropic medium, such as a magnetically gyrotropic plasma, is considered. With the aperture edge, or its tangent, parallel to the gyrotropic axis, the E-polarized field of the wave is unaffected by the anisotropy and attention is confined to the H-polarized field. From the asymptotic form of the exact solution for half-plane diffraction, a coefficient is extracted and the geometrical theory of diffraction used to derive expressions for singly and first-order multiply scattered fields of a slit and, for normal incidence, of a circular aperture. Far-field diffraction patterns of a normally incident wave are shown of slits with ka ranging from 3 to 8, where k is the propagation constant in the medium and 2a is the slit width, for various degrees of anisotropy. The patterns indicate an enhancement in the forward direction for a highly anisotropic surrounding medium. While the phase of the patterns is asymmetrical about the forward direction, their amplitude is not, in contrast with results obtained from approximate solutions for radiation from a small aperture.
SENSITIZED FLUORESCENCE IN VAPORS OF ALKALI METALS: VI. ENERGY TRANSFER IN COLLISIONS BETWEEN RUBIDIUM AND INERT GAS ATOMS
Authors: Pitre Bruce , Rae A. G. A. , Krause L.
Published: April 2011

The total cross sections for inelastic collisions between rubidium and inert gas atoms, leading to a transfer of excitation between the 5 2P1/2 and 5 2P3/2 levels in rubidium, have been determined in a study of sensitized fluorescence in rubidium – inert gas mixtures. The experiments were performed at a rubidium vapor pressure of 1.5 × 10−6 mm Hg, at which there is no imprisonment of resonance radiation, and over a range of inert gas pressures extending from 1 to 350 mm Hg. The cross sections Q1(5 2P1/2 → 5 2P3/2) and Q2(5 2P1/2 ← 5 2P3/2) are as follows: Rb–He: 7.6 × 10−18 and 10.3 × 10−18 cm2; Rb–Ne: 1.7 × 10−19 and 2.3 × 10−19 cm2; Rb–A: 1.0 × 10−19 and 1.6 × 10−19 cm2; Rb–Kr: 6.4 × 10−20 and 1.5 × 10−19 cm2; Rb–Xe: 7.9 × 10−20 and 2.1 × 10−19 cm2. The cross sections are subject to two apparent anomalies: they do not vary monotonically with the polarizabilities of the inert gases and not all of their ratios Q1/Q2 have values predicted by the principle of detailed balancing. These properties of the cross sections, as well as a partial disagreement with Franck's rule, are interpreted qualitatively in terms of a "free particle" interaction between the inert gas atoms and the 5 2P orbital electron in rubidium. A competing process involving three-body collisions and the possible formation of Rb – inert gas van der Waals' molecules is also suggested.
SENSITIZED FLUORESCENCE IN VAPORS OF ALKALI METALS: VIII. ENERGY TRANSFER BETWEEN THE 4 2P LEVELS IN POTASSIUM INDUCED BY INELASTIC COLLISIONS
Authors: Chapman G. D. , Krause L.
Published: April 2011

Sensitized fluorescence in potassium vapor and its mixtures with inert gases was investigated in order to determine cross sections for the inelastic collisions leading to excitation transfer between the 4 2P1/2 and 4 2P3/2 states in potassium. The study was carried out at potassium vapor pressures of about 10−6 mm Hg, which were not formerly accessible to such experiments, and in the absence of radiation trapping. The cross sections Q1(4 2P1/2 → 42P3/2) and Q2(4 2P1/2 → 4 2P3/2) are as follows: for K–K collisions: 370 and 250 Å2; for K–He: 60 and 41 Å2; for K–Ne: 14 and 9.5 Å2; for K–A: 37 and 22 Å2; for K–Kr: 61 and 41 Å2; for K–Xe: 104 and 72 Å2. These values supersede those published previously (Chapman, Krause, and Brockman 1964; Chapman and Krause 1965). The cross sections for collisions between potassium and inert gas atoms do not increase monotonically with the polarizabilities of the inert gases but behave similarly to the electron – inert gas elastic scattering cross sections. This behavior is interpreted on the basis of a semiclassical model for the interaction, which involves overlap forces.
PRESSURE BROADENING OF THE ROTATIONAL RAMAN LINES OF SOME SIMPLE GASES
Authors: Jammu K. S. , John G. E. St. , Welsh H. L.
Published: April 2011

Self-broadening of the rotational Raman lines of O2, N2, CO2, and CO, and foreign-gas broadening of O2 and N2 by He and Ar were measured in the pressure range from 7 to 43 atm at room temperature. Spectrograms were obtained with Hg 2 537 Å as exciting line and a reciprocal linear dispersion of 11.2 cm−1 per mm. In each case the broadening was found to be proportional to the pressure so that a broadening coefficient [Formula: see text] could be defined. The broadening coefficient shows a monotonie decrease with increasing rotational quantum number J. The values of [Formula: see text] for N2 and their variation with J are in good agreement with the values calculated theoretically by Van Kranendonk on the basis of quadrupolar interaction in the impact approximation.
QUASI-LINEAR THEORY OF TRANSVERSE PLASMA INSTABILITIES WITH APPLICATIONS TO HYDROMAGNETIC EMISSIONS FROM THE MAGNETOSPHERE
Authors: Watanabe Tomiya
Published: April 2011

Transverse instabilities in two magnetoactive plasma streams are investigated theoretically. The approach taken is to investigate how a small signal transverse electromagnetic wave, which, in a zero temperature background plasma, can be propagated as a circularly polarized sinusoidal wave (with the two possible modes, electron and ion cyclotron) along the external magnetic field, behaves under perturbations arising from the existence of the streaming plasma and the nonlinear terms in the Boltzmann equations describing the plasma particle distribution. The perturbation method originally given by Bogoliuboff et al. and since developed into the so-called multiple time-scale method by Frieman et al. (1963) is employed to solve the problem. The cyclotron instability is rediscovered as the effect of the lowest order (viz., the most effective) among all possible instability processes. The wave amplitude is found to grow gradually with time in the vicinity of the cyclotron resonance frequency because of the instability. The effective wave frequency is also found to change gradually in time. The growth rate of the signal intensity and the rate of the time change in the frequency are calculated for a case of geophysical interest, viz. the instability in the ion cyclotron mode of waves by a proton stream proposed as the generation mechanism for hydromagnetic (hereafter hm) emissions. The location of the occurrence of the instabilities is taken to be the equatorial region in the outer magnetosphere. A model is considered where the instabilities occur in the region with L value equal to about 5.6. The growth rate of the signal strength calculated with reasonable values of the geophysical parameters involved is in agreement with the observations. Calculations of the rate of the time change in the wave frequency show that the frequency is seen to increase with time, and the rate, which is of the order of 0.1 c.p.s./minute, is comparable to that obtained from observations, showing that the process proposed for hm emissions may be correct.
FLUCTUATIONS IN BRIGHTNESS FROM QUIET-FORM AURORAS
Authors: Paulson K. V. , Shepherd G. G.
Published: April 2011

Observations of brightness fluctuations in quiet-form auroras have been made from Saskatoon. The resulting data sequences were analyzed on the basis that they are physical realizations of second-order stationary stochastic processes. It is shown that these fluctuations occur almost always and that certain reciprocal frequencies dominate the fluctuation spectra. The spectral-density estimates invariably show one and sometimes two pronounced peaks in the reciprocal frequency range of 3–20 seconds. The scale size of the spatial fluctuations has been determined to be of the order of 50 kilometers. These spatial fluctuations are anisotropic. At times, a disturbance has been detected moving within a quiet form and the propagation speed has been measured. Simultaneous fluctuations in brightness at wavelengths of 3 914 Å and 4 861 Å have been observed and their nature is described. Examination of a simple model based on the precipitation of trapped electrons reveals that the observations can be explained only partially by such a mechanism.
EQUILIBRIUM COMPUTATIONS FOR MULTICOMPONENT PLASMAS
Authors: Zeleznik Frank J. , Gordon Sanford
Published: April 2011

A method is presented for the calculation of multicomponent plasma properties. The method includes both Debye–Hückel and ionization potential lowering effects. These effects are shown to be partially compensating. A perturbation technique is used to make the calculation compatible with a scheme used for calculating ideal gas properties. Thermodynamic derivatives, such as heat capacity, can be calculated directly.
A NOVEL IONOSPHERIC CYCLOTRON RESONANCE PHENOMENON OBSERVED ON ALOUETTE I DATA
Authors: Muldrew D. B. , Hagg E. L.
Published: April 2011

Characteristics of an extraordinary wave trace recently identified on Alouette I topside ionograms, and called the remote resonance trace by Hagg (1966), are discussed in detail. From the observations it has been deduced that the radio energy associated with the production of this trace propagates along an ionospheric magnetic field-aligned wave guide. The electric field of an h.f. wave propagating along such a guide would have a gradient normal to the earth's magnetic field, and because of this gradient the wave could excite an electron–cyclotron resonance in a region of the ionosphere that includes the height where the wave frequency is equal to twice the electron gyrofrequency. At some time delay after the wave has passed through the resonant region, the resonating electrons generate an extraordinary wave, which propagates upward along the guide and is subsequently received by the satellite. This wave is responsible for the production of the remote resonance trace. The equation for the time delay is given and the resonance trace computed, using this equation, is shown to be in good agreement with the observed resonance trace for a specific ionogram.
RADAR EQUIPMENT FOR CONTINUOUS METEOR OBSERVATIONS
Authors: Neale M. J.
Published: April 2011

The specifications and the component parts of a 20-kW meteor radar working at about 33 Mc/sec are described. In the design of this equipment special attention was given to long-term use and constancy of performance. Serviceability characteristics are noted for 8 years of continuous use.
AXISYMMETRIC RESISTIVE INSTABILITIES IN THE HARD-CORE PINCH
Authors: Hosking R. J. , Blackwell J. H.
Published: April 2011

The hard-core pinch configuration with azimuthal equilibrium magnetic field only is considered. Provided finite conductivity is included, unstable axisymmetric modes are found. These instabilities are apparently due to nonlocalized plasma diffusion across the magnetic flux lines. On the laboratory scale, the growth rates do not appear to be significant, when the material of the conducting shell is mercury. For a hydrogen plasma shell, however, it appears that the growth rates may be of practical importance. It is found that the ratio of the current in the shell to the hard-core current has a significant effect on the "spectrum" of instabilities. This effect in part accounts for the observed relative stability of the hard-core system when there is no axial equilibrium magnetic field.
A MATHEMATICAL MODEL FOR ANALYSIS OF WAVE PROPAGATION IN A LINEARIZED VERTICALLY NONUNIFORM PARTIALLY IONIZED GAS
Authors: Raemer Harold R.
Published: April 2011

Wave propagation in fully and partially ionized gases, with and without magnetic fields, has been treated by several workers; e.g., Tanenbaum and Mintzer (1962) obtained dispersion relations for a linearized and spatially uniform gas of electrons, positive ions, and neutrals. The present paper discusses the basic formulation and mathematical treatment of wave propagation in a linearized electron – ion – neutral gas, with static magnetic field, in which ambient-gas parameters vary arbitrarily vertically and are uniform horizontally.A standard formulation of the general problem is discussed via Boltzmann and Maxwell equations. By momentum-space averaging, the Boltzmann equation yields motion, continuity, and dynamic adiabatic state equations. These are combined to yield neutral and plasma equations of motion, continuity, and adiabatic state and a generalized Ohm's Law. Steady-state plane-wave solutions of the form exp[−i(ωt – kxx)] are assumed, reducing the x, y, and t dependence to algebraic relations, but the equations remain differential in z. The system consists of 10 simultaneous coupled ordinary first-order complex differential equations and 11 simultaneous complex algebraic equations in 21 complex unknowns.The second part of the paper is a discussion of the solution of this coupled algebraic differential equation system, equivalent to the system arising in the analysis of coupled linear electrical networks. Referring to the literature of differential equations and modern automatic control systems, various purely analytical approaches are discussed with emphasis on their deficiencies in obtaining practical numerical results with an arbitrary z variation. The Runge–Kutta step-by-step-procedure was invoked eventually and a Fortran program based on this technique was written. The program can be used to obtain accurate numerical solutions to many problems involving wave propagation in a linearized, vertically nonuniform electron – ion – neutral gas without requiring drastic simplifying assumptions for the vertical nonuniformity. This program can be used, by changing input parameter values, to treat such diverse problems as the perturbing effect of acoustic–gravity waves on ionospheric electron density, electromagnetic wave propagation in the vertically inhomogeneous ionosphere, MHD waves high in the ionosphere, or various kinds of wave propagation in prepared plasmas with a one-dimensional inhomogeneity. Numerical solutions for the acoustic – gravity wave – plasma interaction problem and their interpretation will be reported in a later paper.
DIFFRACTION BY A SLIT OF INTERMEDIATE WIDTH IN AN ANISOTROPIC PLASMA
Authors: Zitron N. R.
Published: April 2011

The problem of diffraction by a wide slit in a uniaxially anisotropic plasma is solved by means of a multiple-scattering technique. The principal result is the consideration of the effect of the dipole term, which is the principal contribution to the interaction in certain ranges. Numerical data obtained from the analytical results are used to discuss the effects of the various kinds of interaction, anisotropy, and slit widths on the diffraction pattern of the slit at normal incidence.
PROPERTIES OF LEVELS AT 6.69 AND 6.88–6.89 MeV IN 28Si
Authors: Levesque R. J. A. , Ollerhead R. W. , Blackmore E. W. , Kuehner J. A.
Published: April 2011

Levels at 6.69, 6.88, and 6.89 MeV were observed in the 16O(16O, α)28Si reaction, and angular correlations were measured for the resulting gamma-ray transitions, using the geometry in which the alpha particle is detected at 0°. The level at 6.69 MeV had not been reported previously and was assigned spin and parity 0+. The doublet of levels at 6.88–6.89 MeV was not resolved in these measurements, but angular correlations of the gamma-ray transitions were possible, using spectrum subtraction techniques. One member of the doublet, previously assigned spin 3, has a strong ground-state transition; the angular correlation for this transition confirms a 3− assignment to this level. The other member of the doublet, which decays almost entirely to the first excited state, could not be assigned a spin on the basis of these measurements. However, taken in conjunction with other measurements, an assignment of 4+ is favored.
NONLINEAR PLASMA OSCILLATIONS WITH TRAPPED ELECTRONS
Authors: Wang H. S. C.
Published: April 2011

Propagation of stationary longitudinal waves in a hot (Maxwellian) plasma is investigated, when the wave amplitude, phase velocity, and electron temperature are such that the relativistic effect is negligible but trapped electrons must be taken into account. The treatment is based on an exact solution of the nonlinear collisionless Boltzmann equation compatible with the equilibrium electron distribution. The existence, propagation, and amplitude limit of a dimensionless periodic potential wave ψ are discussed in terms of the behavior of the first integral Y(ψ) of the Poisson equation. It was found that, for α = mW2/2κT (W is the wave velocity) less than a critical value αe = 0.854, no stationary wave can exist, irrespective of its amplitude. For α slightly greater than αe, wave propagation is limited to small amplitude and low frequency. As α is further increased, waves of progressively larger amplitude can also propagate; but their amplitude is limited when Y(ψ) becomes tangent to the ψ axis at ψmin because of the excessive number of electrons trapped in the wave troughs. An expression for the maximum wave amplitude as a function of α is derived and plotted. Wavelengths for different values of α and amplitude levels are computed numerically and plotted as dispersion curves. A typical example for wave form is also displayed to show the progressive distortion from pure sinusoids due to nonlinearity and the effect of trapped electrons.
THE CHARGE SPECTRUM AND INTERACTIONS OF RELATIVISTIC HEAVY NUCLEI IN THE PRIMARY COSMIC RADIATION
Authors: Judek B. , Heerden I. J. van
Published: April 2011

The charge spectrum of relativistic heavy nuclei in the primary cosmic radiation has been investigated in a stack of nuclear emulsions exposed over Texas at a ceiling height of 136 000 ft. Charges of 601 primary and of 203 fast secondary nuclei arising from fragmentations have been determined. Using a "range" criterion to count δ rays, charge resolutions up to Z = 15 have been obtained.All of the tracks have been followed through the stack and the interaction mean free paths in emulsion and the fragmentation probabilities evaluated for individual elements up to Z = 15. Using these probabilities, the relative abundances at the top of the atmosphere were 12.7 ± 1.3% L nuclei [Formula: see text], 63.5 ± 3.5% M nuclei [Formula: see text], 13.6 ± 1.6% H3 nuclei [Formula: see text], 1.7 ± 0.5% H2 nuclei [Formula: see text], and 8.5 ± 1.4% H1 nuclei [Formula: see text]. It was found that the interaction mean free paths in emulsion of the M and H nuclei were about 10% lower than previous experimental and calculated values. The fragmentation probabilities were generally in agreement with previous determinations, except for a significantly high value for the fragmentation of H1 to L nuclei.
ON A CYLINDRICAL ANTENNA IN A HOMOGENEOUS ANISOTROPIC MEDIUM
Authors: Aoki K.
Published: April 2011

The admittance problem of an antenna imbedded in a homogeneous anisotropic medium in which the dielectric tensor is given by the form in eq. (1) is formulated by the theory of Fourier transforms, and analyzed with the aid of the Wiener–Hopf technique. The current distribution and the input admittance of an infinite and finite antenna are evaluated approximately under the following assumptions: (1) the medium is loss free, (2) (radius of the antenna/wavelength) [Formula: see text], (3) the nondiagonal elements of the dielectric tensor are very small compared with its diagonal elements and ωp < ω < ωe (ωp, ω, and ωe are the plasma, signal, and cyclotron frequencies), (4) (antenna length/wavelength) is not small. Our present results have forms similar to the well-known solutions in an isotropic medium, except for two distinctions. The first is that a circulating current flows on the antenna, although its magnitude is very small. The second is an additional resonance phenomenon due to the interaction of two traveling current waves with slightly different propagation constants.
ROTATIONAL ANALYSIS OF THE E–X AND C–X BAND SYSTEMS OF THE CuI MOLECULE
Authors: Nair K. P. R. , Upadhya K. N.
Published: April 2011

The rotational structure of the CuI bands has been obtained and some of the bands of the E–X and C–X systems have been analyzed. The transitions involved are found to be E1Σ–X1Σ and C1Σ–X1Σ which are closely analogous to those of the E–X and C–X systems of the CuCl bands. The molecular constants obtained are as follows:[Formula: see text]
THEORY OF COLD NEUTRON SCATTERING BY HOMONUCLEAR DIATOMIC LIQUIDS: I. FREE ROTATION
Authors: Sears V. F.
Published: April 2011

The cold neutron scattering cross section for a system of homonuclear diatomic molecules with arbitrary nuclear spin and an arbitrary ortho–para ratio is calculated in first Born approximation, assuming that the molecular rotation is unhindered. The cross section is expressed in the form of an expansion in terms of the angular momentum transfer. This expansion is shown to be rapidly convergent for all the permanent homonuclear diatomic liquids. To the extent that the intermolecular forces are described by an isotropic Lennard-Jones potential, the terms in the expansion can be calculated with the help of the law of corresponding states and the observed scattering functions for the condensed inert gases. The problem of neutron diffraction by homonuclear diatomic liquids is also investigated.
DIRECTIONAL CORRELATIONS IN 127I
Authors: Neeson J. F. , Roalsvig J. P. , Arns R. G.
Published: April 2011

Gamma–gamma coincidence measurements on the decay of 9.3-hour 127Te to 127I form the basis of the decay scheme presented, which confirms the accepted decay sequence. Directional correlation measurements have been made on the 215–203 keV and 360–58 keV cascades. The respective correlation functions are:[Formula: see text]The directional correlation results have been interpreted in terms of the accepted spin sequence, and limits of multipole mixtures are presented. A short discussion of the collective properties of the levels is presented.
ATMOSPHERIC CONTRIBUTION TO THE DIURNAL VARIATION OF THE COSMIC-RAY MESON INTENSITY AT DEEP RIVER
Authors: Bercovitch M.
Published: April 2011

We have established the correlation between the atmospheric temperature contribution to the diurnal variation observed by a meson monitor at Deep River and the diurnal variation of two easily and continuously observable atmospheric variables, the ground-level air temperature and the barometric pressure. The atmospheric meson diurnal variation vector is taken to be, on a statistical basis, A = M−RN, where M and N represent the observed meson-monitor and neutron-monitor diurnal variations and R is the factor of proportionality between the meson and neutron monitor responses to the primary anisotropy. It is found that A is proportional in amplitude to T, the ground-level temperature diurnal variation, and, further, that T and the barometric-pressure diurnal variation P are proportional in amplitude. The "best-fit" representation of A in terms of T and P is determined by minimizing the mean-square deviation between the daily vectors RN and (M−A). Where A = CtT + CpP, the best fit occurs when Ct = −0.0052%/ °C, Cp = 0.038%/mb, R = 0.47, and the phase of T is shifted by + 1.0 hour. These values apply to Deep River, where the original hourly meson data have been barometer-corrected using a coefficient of 0.16%/mb.
TEMPORAL VARIATIONS OF OUTER RADIATION ZONE ELECTRON INTENSITIES AT 1 000 km
Authors: McDiarmid I. B. , Burrows J. R.
Published: April 2011

The intensities of electrons in the outer Van Allen radiation zone are examined as a function of time using particle detectors on the Alouette 1 satellite. The study covers the period December 1962 to May 1963, during which several moderately large magnetic storms occurred. It is shown that within a few hours after the onset of a magnetic storm the intensity of electrons above 40 keV increases consistently, while the intensity of electrons above 3.9 MeV may decrease and remain low for about a day, or it may remain at prestorm levels for about a day, after which an increase in intensity usually follows. During magnetically quiet periods, electron intensities decay with time constants τ which depend on the particle energy. Typical values of τ are as follows: electrons E > 40 keV at L ~ 6, τ = 4 ± 1 days; E > 250 keV at L ~ 4.7, τ = 6 ± 2 days; E > 3.9 MeV at L ~ 4.3, τ = 14 ± 2 days. Some of the measurements are compared with Explorer 14 measurements which were made at the same time, and significant differences are observed in the behavior of energetic electrons on the same L shells at 1 000 km and near the equatorial plane. For electrons above 40 keV an attempt is made first to relate intensity increases at times of magnetic disturbances to an influx of particles from the "tail" of the magnetosphere and secondly to relate the intensity decreases at magnetically quiet times to a loss of particles into the atmosphere.
EFFECT OF ION SHEATH ON RADIATION IN A MAGNETOIONIC MEDIUM: I. SOURCE CURRENT PARALLEL TO THE MAGNETOSTATIC FIELD
Authors: Seshadri S. R. , Bhatnagar K. L.
Published: April 2011

The radiation characteristics of an axially oriented point source of electric current and a filament of finite length with a triangular current distribution are treated for the case in which these sources are situated at the center of an infinite cylindrical column of free space and surrounded by a homogeneous, loss-free magnetoionic medium. The direction of the magnetostatic field is assumed to be parallel to the axis of the free-space column which is an idealization for the geometry of the ion sheath formed around the antenna in the ionosphere. The dependence of the radiation resistance of these sources on the frequency and the ion-sheath thickness is examined. It is found that, within the framework of the classical magnetoionic theory, the radiation resistance of even a point source of electric current remains finite for all frequencies, provided the ion-sheath effects are included. Also the radiation resistance of a finite-length filament with a triangular current distribution is found to be insensitive to the changes in the thickness of the ion sheath. This result is in conformity with the experimental observations, which indicate no data variations correlated with the changes in the thickness of the ion sheath.
CONTINUOUS-HEATING ADIABATIC CALORIMETER FOR THE RANGE 300 TO 475 °K—THE SPECIFIC HEAT OF α-Al2O3
Authors: Martin Douglas L. , Snowdon Robert L.
Published: April 2011

A continuous-heating calorimetric apparatus with semiautomatically controlled adiabatic shields is described. The calorimeter vessel is of novel construction. Measurements on the Calorimetry Conference Standard Sample of Aluminum Oxide give results about 0.25% higher than those tabulated by Furukawa et al. (1956).
NEW ALPHA-DECAY BARRIER PENETRABILITIES WITH IGO POTENTIAL: EVEN-MASS NUCLEI
Authors: Kohlmann L. , Vörös T.
Published: April 2011

The lgo potential is used for the calculation of barrier penetrabilities for ground-state and excited-state transitions of even–even nuclei and for transitions of odd–odd nuclei, measured after 1959. The barrier penetration factors were calculated by numerical integration in the WKB approximation, taking into consideration centrifugal barrier effects for even–even nuclei, but ignoring non-central interactions. Using the calculated penetration factors and the experimental alpha half-lives, the reduced level widths were calculated in each case. The barrier penetration factors and the reduced level widths are given for total decay energy (alpha-particle energy plus electron-screening correction plus recoil energy).
ABSORPTION SPECTRUM OF THE NO MOLECULE: VI. BAND STRUCTURES BELOW 1 600 Å, RYDBERG STATES C2Π, D2Σ+, K2Π, M2Σ+, S2Σ+, NON-RYDBERG STATES B2Π, L2Π AND THEIR INTERACTIONS
Authors: Lagerqvist A. , Miescher E.
Published: April 2011

The study of the absorption spectrum of the NO molecule has been continued on plates taken in the fourth order of a 10.5-m vacuum spectrograph. The spectra of 14N16O, 15N16O, 14N18O, and 15N18O gases, each kept at liquid-oxygen temperature, were photographed separately. Rotational analyses were carried out for many bands observed below 1 600 Å. Constants for levels of the Rydberg complexes 3p, 4s, 4p, and 5s have been derived. These levels include ν = 5 and ν = 6 of the C2Π state, levels that interact with the levels ν = 21 and 24 respectively of the configurationally different B2Π state. It is shown that the vibrational levels, now well established above the energy where the potential curves of the C and B states cross, are to be attributed to "crossing" curves.The level ν = 4 of the L2Π state, which was discerned in the spectra of the heavier isotopes only, coincides in 14N16O with the level ν = 6 of C2Π and produces a strong three-level perturbation. The level, perturbed in this way, has the appearance of a separate electronic state in 14N16O and at one time was so identified.Many interaction energies are determined, and the new systems of "deper-turbed" levels are thoroughly discussed.
HALL EFFECT AND ELECTRICAL CONDUCTIVITY OF Cu2O MONOCRYSTALS
Authors: Fortin E. , Weichman F. L.
Published: April 2011

Hall-effect and electrical conductivity measurements were performed on Cu2O single crystals both before and after heating the samples in vacuo at temperatures ranging from 200 °C to 800 °C. Both the absolute values of the mobility and the conductivity, as well as their temperature dependence, were found to be strongly altered by the heating process. Room-temperature conductivities usually dropped from 10−6 ohm−1 cm−1 to 10−8 ohm−1 cm−1, while the mobility increased from about 30 to 100 cm2 V−1 sec−1 after heating to 300 °C. At the same time, the activation energies for the conductivity increased and a region of exponential temperature dependence for the mobility showed up. Vacuum heating above 800 °C again changed the sample characteristics quite drastically and appeared to stabilize them with respect to their environment with different atmospheres. Reproducibility for a given sample and from sample to sample could be obtained only after heating the samples in vacuo. The results are compared with previous investigations, and it is suggested that different surface conditions or thermal histories could account for the wide variety of data found in the literature.
A MEGAWATT PULSE RADAR TRANSMITTER FOR METEOR RESEARCH
Authors: Neale M. J.
Published: April 2011

A meteor radar with peak power well into the megawatt range was built for use near Ottawa and has been operated intermittently since 1961. The pulse transmitter produces 4 MW at 33 Mc/sec and no serious difficulties have been encountered in 1 200 hours of use. Details of the design are discussed.
PRODUCTION DE RAIES SPECTRALES DE He I ET He II PAR L'EXCITATION D'ATOMES He+ ACCÉLÉRÉS AU MOYEN D'UN VAN DE GRAAFF
Authors: Bashkin S. , Beauchemin S. J. G.
Published: April 2011

We have used the fast beam-foil technique to excite various levels in He I and He II, and have observed three spectral lines in He I and six in He II. Three of the He II lines exhibit peculiar intensity patterns.
LASER LINES FROM CO2 IN THE 11–18 MICRON REGION
Authors: Hartmann B. , Kleman B.
Published: April 2011

A number of lines at 11 microns emitted from a pulsed CO2 laser have been identified as the P branch of the CO2 vibrational transition (0111)–(1110). Five other transitions, between 13 and 18 microns, have been observed. The possibilities that these are perpendicular transitions with Δν2 = 1 are discussed.
MEASUREMENTS OF ANISOTROPIC PLASMAS USING A TURNSTILE MULTIPLE-PROBE POLARIMETER
Authors: Bachynski M. P. , Osborne F. J. F. , Gibbs B. W.
Published: April 2011

A turnstile multiple-probe polarimeter has been designed for plasma diagnostics at microwave frequencies. With the polarimeter, it is possible to measure simultaneously the amplitude and phase of the space quadrature components of an electromagnetic wave of arbitrary polarization. This technique is thus well suited for determining the properties of time-varying or steady-state anisotropic plasmas. Measurements have been conducted at a frequency of 9.2 Gc on a helium afterglow in a magnetic field, using both linearly polarized and circularly polarized incident plane waves. The agreement of these experiments with theory indicates that the multiple-probe polarimeter can be a reliable tool for plasma measurements.
ACOUSTIC PRESSURE DISTRIBUTIONS AND ENERGY REFLECTIONS IN A FLUID-FILLED CYLINDER
Authors: Giguere J. C.
Published: April 2011

From consideration of the expression for the acoustic velocity potential in a semi-infinite liquid cylinder, it is shown that the acoustic energy density is a maximum along the axis of the cylinder and a minimum along the wall.The amount of energy returned from a disk reflector whose center is located along the pipe axis is shown to depend, for small reflectors, primarily upon the disk diameter, and for large reflectors upon the energy distribution in the cylinder. Experimental results bear out the theory.
ÉTUDE THÉORIQUE DES PERTURBATIONS HOMOGÈNES : I. APPLICATION AUX INTERACTIONS Π–Π ET Δ–Δ DE NO
Authors: Felenbok P. , Lefebvre-Brion H.
Published: April 2011

A theoretical interpretation of homogeneous perturbations is proposed for the case of two electronic excited states that differ strongly in electron configuration. The interaction parameter H can be expressed in terms of the vibrational overlap integral and the electrostatic interaction between the two states. In the case of the Π–Π and Δ–Δ interactions in the spectrum of the NO molecule, a semi-empirical calculation of this parameter is made, using Morse functions for the vibrational part and the LCAO-MO SCF function for the electronic part. The comparison with the "experimental" values given by Lagerqvist and Miescher supports this interpretation.
THE ELECTRICAL PROPERTIES OF ALUMINA AT HIGH TEMPERATURES
Authors: Matsumura T.
Published: April 2011

The ionic transport number and the d-c. electrical conductivity of single-crystal and polycrystalline alumina have been studied between 1 000 °K and 1 750 °K at an oxygen partial pressure of 0.2 atm. The ionic transport number was determined by the galvanic-cell e.m.f. measurements; the electrical conductivity was measured by the three-terminal method.It was found that alumina is a mixed conductor, being predominantly an ionic conductor at temperatures below 1 100 °K and predominantly electronic at temperatures higher than 1 600 °K. The activation energies found for the electrical conductivity of the single-crystal and polycrystalline specimens are 0.8 eV and 2.4 eV respectively in the ionic range and 3.0 eV and 3.7 eV in the electronic range.
SEMICLASSICAL THEORY OF PHONON RADIATION PROCESSES
Authors: Kranendonk J. Van
Published: April 2011

For the various forms of the spin-lattice coupling in paramagnetic salts of the iron group ions, derived in a previous paper, a semiclassical phonon radiation theory is developed. The phonon fields are analyzed in terms of phonon multipole fields, and the phonon multipole moments are expressed in terms of the effective spin variable. The phonon multipole fields are all monopole fields in the sense that the corresponding static fields fall off at large distances as R−2, but they are monopole, dipole, and quadrupole fields as far as the angular dependence is concerned. As a result, the rates of emission by the different phonon multipoles are all of the same order of magnitude. The equation of motion of a dressed spin is derived, and the phonon radiation damping is shown to depend on the third time derivative of the phonon multipole moments. As an application, the classical theory of the resulting spin-lattice relaxation is discussed briefly.
THE MASSIVE SPIN–TWO FIELD
Authors: Deser S. , Trubatch J. , Trubatch S.
Published: April 2011

The energy of the free massive spin-two field is exhibited as a manifestly positive-definite function of its canonical variables. The indefiniteness of the form recently obtained by Adler is shown to be only apparent in nature. A summary of the canonical reduction of the theory is given in the Appendix.
IMAGES NORMALES ET STRIOSCOPIQUES FORMÉES PAR UN RÉSEAU ET LA FIGURE DE DIFFRACTION (Sin X)/X
Authors: Delisle Claude
Published: April 2011

An objective diaphragmed by a wide slit, parallel to a narrow slit of the object plane, gives as a picture of the latter a well-known diffractional structure (sin X)/X. A new distribution of coherent luminous states is realized by superposing on this image a grating whose narrow slits are parallel to those of the system, equidistant, and separated by a distance equal to half the width of the central portion of (sin X)/X. The pupil obtained this way gives a repeated diffraction pattern whose structure and properties are studied.It is established particularly that the image has a periodic structure and that it can readily be broken down into adjoining zones that are deductible by a simple shifting of any one of them. So it is sufficient to study the central zone, which is placed symmetrically on the optical axis and on which the distribution of intensity and phase is symmetrical.The repeated diffraction patterns present two distinct aspects: normal images and strioscopic images, whether the center of the pattern (sin X)/X is located inside or outside the region bordered by the marginal slits of the grating.Similarities are brought out between the images formed by gratings with different numbers of slits. We therefore deduce an evolution process that justifies and completes a previous paper on the repeated diffraction patterns given by an infinite grating.There is satisfactory agreement between the theory and the experimental recordings.
DIRECT MEASUREMENTS OF THE HALF-LIVES OF SOME SHORT-LIVED XENON AND CESIUM ISOTOPES
Authors: Archer N. P. , Keech G. L.
Published: April 2011

Experimental techniques that are useful in the production and study of the fission product rare gases have been developed. The experimental developments reported in this work include a new radiation-resistant fission-gas-emanating compound, a fast technique for the separation of trace quantities of xenon or krypton from a fission gas mixture, and a "charged-wire chamber" used in the continuous removal of decay products from radioactive gas sources.These methods have been applied in the determination, by direct counting techniques, of the half-lives of 138Cs (32.3 ± 0.1 min), 139Cs (9.0 ± 0.15 min), 140Cs (63.8 ± 1.2 sec), 137Xe (3.80 ± 0.05 min), 139Xe (14.1 ± 0.8 min), 139Xe (41.2 ± 0.15 sec), and 140Xe (13.7 ± 0.15 sec). These results compare favorably with the most recently published measurements of these half-lives.
FARADAY-CUP MEASUREMENT OF PROTON TOTAL REACTION CROSS SECTIONS AT 100 MeV
Authors: Kirkby P. , Link W. T.
Published: April 2011

The proton total reaction cross sections of 41 elements have been measured at 99 MeV, using a double Faraday cup to measure the proton-beam attenuation. The results are consistent with the semiclassical form of the absorption cross section with a nuclear radius parameter of 1.47 fm (1 fm = 10−13cm) and a mean free path for 99-MeV protons in nuclear matter of 5.7 fm.
THE ELECTRIC AND MAGNETIC FIELDS AT THE SURFACE OF A FLAT CONDUCTING EARTH IN THE NEAR FIELD OF AN OSCILLATING LINE CURRENT
Authors: Dosso H. W.
Published: April 2011

The electric and magnetic fields at the surface of a flat conducting earth in the near field of an oscillating line current are studied in this work. The equations for the amplitudes and phase angles developed by Law and Fannin (1961) were used for the numerical calculations. The source heights (h = 105 to 4 × 105 meters), the source frequencies (ƒ = 10−3 to 10 sec−1), and the earth conductivities (σ = 10−5 to 10 mho/m) considered are of interest in geophysics.
INTERMEDIATE-STATE REORIENTATION OF ORIENTED NUCLEI
Authors: Daniels J. M. , Misra Sushil K.
Published: April 2011

When radioactive nuclei in a paramagnetic ion at low temperatures become oriented (the magnetic h.f.s. method of nuclear orientation) and decay by β emission followed by a delayed γ ray, frequently, these nuclei become reoriented between the emission of the β ray and the γ ray, and this reorientation affects the observed angular distribution of the γ ray. The theory of this reorientation process is presented, assuming a time-independent Hamiltonian during the reorientation period. Numerical calculations of the effects to be expected on this static reorientation model have been made for 175Yb, 147Nd, and 141Ce in cerium magnesium nitrate, 57Co in cerium zinc nitrate, and 147Nd in neodymium ethyl sulphate. These calculations are compared with the reported experimental results. The experimental values for 147Nd in neodymium ethyl sulphate, 141Ce in cerium magnesium nitrate, and 57Co in cerium zinc nitrate could be explained by the static reorientation model; the others could not. The need is stressed for more reliable experimental results, in order to develop the theory of reorientation further.
CROSS SECTIONS AND RESONANCE INTEGRALS FOR THE NEUTRON ACTIVATION OF 103Rh
Authors: Walker W. H. , Copley L. A.
Published: April 2011

The cadmium ratio method has been used to determine the ratio I′/σ0 for activation of 103Rh, where I′ is the reduced resonance integral and σ0 is the 2 200-m/s cross section. For the production of 104gRh we obtain I′/σ0 = 8.1 ± 0.3 and, for 104mRh, I′/σ0 = 7.4 ± 0.3. These results disagree with a value of ~3.5 obtained in an earlier cadmium ratio measurement. We have also measured the half-lives of the two isomers. In the following table, which summarizes our results, the thermal cross sections are normalized to an absorption cross section in 103Rh of 146 barns and a value of 12.2 for the production of 104gRh relative to 104mRh per 103Rh capture.[Formula: see text]The total reduced resonance integral is 1 175 barns for activation compared with a value of 1 015 ± 25 barns for absorption derived from published resonance parameters.
THE THERMAL CONDUCTIVITY OF PURE LEAD
Authors: Dauphinee T. M. , Armstrong L. D. , Woods S. B.
Published: April 2011

Results of two previously unreported determinations of the thermal conductivity of very pure lead are given. The first set of measurements covered the temperature range −40 to +310 °C, while the second set covered the range 25 to 170 °C to check a small irregularity of the first set. The resistance ratio R/R0 of the first sample was measured from 0 °C to 160 °C. The results may be expressed within 1% by the linear equation K = 0.3555 – 1.36t/104 watt cm−1 °C−1. The Lorenz number drops linearly by about 0.5% between 0 and 150 °C.