bluuebunny/crossref_metadata_2025 huggingface dataset:
DIRECT TUNNEL-CURRENT NOISE IN TUNNEL DIODES FOR SMALL BIASES
Authors: Turner B. E. , Burgess R. E.
Published: April 2011

The Esaki theory describing the current components arising from direct interband tunneling in tunnel diodes has previously been used to predict a relation between the noise spectrum of direct-tunneling currents and the p–n junction voltage (Pucel 1961). In this paper is presented experimental confirmation of this relation, which provides a sensitive test of the Esaki formulation for tunneling currents and indicates as well, that the noise spectrum is independent of the band structure of the semiconductor and that the two oppositely flowing tunnel currents are uncorrelated. These facts form a basis for examining the extent to which the Esaki formulation can be generalized, and the relation independent of band structure, between the direct tunnel-current noise spectrum and the applied junction voltage.
VIBRATIONAL ISOTOPE SHIFTS OF ABSORPTION BANDS OF N2 IN THE SPECTRAL REGION 720–830 Å
Authors: Ogawa Masaru
Published: April 2011

Using a normal-incidence vacuum spectrograph with a 3-meter concave grating, the absorption spectra of 14N2 and 15N2 in the 720–830 Å region have been investigated. From the vibrational isotope shifts, it has been confirmed that the previous assignment given by Ogawa and Tanaka for the Rydberg series converging to the A2Πu state of N2+ was correct. The observed series limits converging to the [Formula: see text] state of 15N2+ are 134735(0,0), 136540(1,0), 138320(2,0), and 140070(3,0) cm−1. The observed vibrational isotope shifts at the series limits in both Rydberg series converging to the A2Πu and the X2Σg+ states of N2+ agree with those values calculated from the known vibrational constants of the A2Πu, and the X2Σg+ states of 14N2+ and the X1Σg+ state of 14N2. In addition to the Rydberg series, four new progressions have been identified tentatively. The observed vibrational quanta of the upper states of these progressions are almost the same, and are, moreover, almost the same as those of the A2Πu state of N2+.
EXPERIMENTAL EVIDENCE FOR THE CHANNELING OF HEAVY IONS IN MONOCRYSTALLINE ALUMINUM
Authors: Piercy G. R. , McCargo M. , Brown F. , Davies J. A.
Published: April 2011

The penetration of radioactive Na24, Kr85, Rb86, and Xe133 ions with energy between 20 and 100 kev into oriented aluminum single crystals has been measured using the anodic stripping technique. Many of the incident ions penetrated several times farther than normal when the ion beam was aligned with directions of closely packed atoms in the crystal lattice. Comparison with theory showed that these ions traveled down channels between the rows of closely packed aluminum ions. The penetration distance and fraction of incident ions traveling these channels increased successively for beams in the directions [111], [100], [112], and [110]. The energy and mass dependence of the penetration of these channeled ions indicates that an appreciable amount of their energy is lost by electron excitation.
THE VACUUM ULTRAVIOLET ABSORPTION SPECTRUM OF DIAZOMETHANE
Authors: Merer A. J.
Published: April 2011

Ultraviolet absorption spectra of CH2N2 and CD2N2 between 2000 Å and 1350 Å have been photographed. Many electronic transitions occur in this region, including a Rydberg series (first reported by Herzberg) which gives the first I.P. of diazomethane as 8.999 ± 0.001 ev. Examination of a band system at 1900 Å has shown that it contains three close-lying electronic transitions, with origins within 200 cm−1. Of the upper states, the two outermost, D and F, are shown by rotational analysis to be of the same symmetry species 1B1, while the third, E, lying between them, seems to be responsible for large perturbations observed in the K structures. By inference, this third state must be 1B2, in Coriolis interaction with the two 1B1 states. Various vibrational bands of this 1900 Å group have been assigned; among these are a number of vibrationally forbidden bands involving one and three quanta of the out-of-plane CH2 bending frequency, ν6. There is strong evidence that the molecule remains planar in these excited states.
THE INTERACTIONS OF NITROGEN AND CARBON MONOXIDE ON POLYCRYSTALLINE TUNGSTEN
Authors: Rigby L. J.
Published: April 2011

Desorption spectra from a polycrystalline tungsten wire have been obtained with a mass spectrometer to study: (a) the effect of preadsorbed nitrogen on the adsorption of carbon monoxide; (b) the reversibility and rearrangement of the carbon monoxide monolayer; and (c) the slow replacement of carbon monoxide by nitrogen. Surface coverages have been measured, and the activation energies of desorption obtained for all phases of carbon monoxide and the β phase of nitrogen.
ELECTRIC POLARIZATION MEASUREMENTS ON YELLOW BIRCH
Authors: Nanassy A. J.
Published: April 2011

Electric polarization spectra of oven-dry yellow birch (Betula alleghaniensis Britt.) were measured over the range of frequencies from 50 kc/s to 50 Mc/s and temperatures from 20° to 100 °C. These observations, which provide only a section of the total dispersion and relaxation absorption spectra of the material, give information on the general variation of the dispersion curve with frequency, temperature, and grain orientation to the electric field, and indicate that the total spectra spread over a wide frequency range, probably from 0 c/s to a few Gc/s and include several absorption peaks and dispersion curves.
LIFETIME MEASUREMENTS OF STATES IN O18 AND Ne22
Authors: Eswaran M. A. , Broude C.
Published: April 2011

Lifetime measurements have been made by the Doppler-shift attenuation method for the 1.98-, 3.63-, 3.92-, and 4.45-Mev states in O18 and the 1.28-, 3.34-, and 4.47-Mev states in Ne22, excited by the reactions Li7(C12, pγ)O18 and Li7(O16, pγ)Ne22. Branching ratios have also been measured. The results are tabulated.[Formula: see text]The decay of the 3.92-Mev state in O18 is 93.5% to the 1.98-Mev state and 6.5% to the ground state and of the 4.45-Mev state 74% to the 3.63-Mev state, 26% to the 1.98-Mev state, and less than 2% to the ground state. In Ne22, the ground-state transition from the 4.47-Mev state is less than 2% of the decay to the first excited state.
THE THERMODYNAMIC DESCRIPTION OF HETEROGENEOUS DISSIPATIVE SYSTEMS BY VARIATIONAL METHODS: IV. CONSEQUENCES OF A SYNTHESIS OF THE ONSAGER AND PRIGOGINE PRINCIPLES
Authors: Kirkaldy J. S.
Published: April 2011

Since Onsager's steady-state dissipation principle and Prigogine's principle of minimum entropy production share a common Euler–Lagrange equation, their configuration spaces may be combined to form a single potential surface. As applied to phase transformations, the entropy production forms a saddle surface in the configuration space of possible stationary states. Those macroscopic variations which involve a change in morphology and a corresponding change in the thermodynamic forces during a spontaneous regression stabilize at a minimum of the entropy production (Prigogine's principle), whereas those microscopic variations, due to fluctuations of the fluxes with fixed forces and fixed morphology, stabilize at a maximum of the entropy production (Onsager's principle). A stable steady state is, therefore, defined by the saddle point.The internal constraints attending stationary phase transformation often exclude the saddle point as a possible state so that unstable configurations are obtained. Dendritic growth of alloy crystals is an example.Some isothermal eutectic or eutectoid reactions may be located at the saddle point. In this case the stabilization of the configuration against microscopic fluctuations requires that the reaction product be in metastable equilibrium. Alteration of the growth conditions may lead to macroscopic instability and a transition to a state lying off the saddle point. These systems evidence their instability by the roughly periodic form of the reaction products.
DIFFRACTION BY A CONDUCTING HALF-PLANE IN AN ANISOTROPIC PLASMA
Authors: Jull E. V.
Published: April 2011

The diffraction of a plane electromagnetic wave by a perfectly conducting half-plane in an anisotropic plasma is considered. The plasma is characterized by a permittivity tensor and the wave is assumed to propagate in a direction normal to the magnetostatic field and the diffracting edge, but its angle of incidence is otherwise arbitrary. Only the H-polarized wave of the incident field, which has a single magnetic field component parallel to the edge, is affected by the anisotropy and the analysis is restricted accordingly. Representing the scattered field as an angular spectrum of plane waves leads to dual integral equations from which an expression for the scattered field is obtained. The total field is then reduced to Fresnel integrals and its far-field behavior is investigated. Agreement with Seshadri and Rajagopal's result for a wave normally incident on the conductor, which was obtained by using the Wiener–Hopf technique, is found. The differences between isotropic and anisotropic solutions to this problem, which arise from the differing boundary conditions on the tangential magnetic field, are examined.
NUCLEAR MAGNETIC RESONANCE IN METAL SINGLE CRYSTALS: I. TIN AND ALUMINUM
Authors: Jones E. P. , Williams D. Llewelyn
Published: April 2011

Nuclear magnetic resonance studies in single-crystal tin specimens have been done at liquid helium temperatures. The Knight shift has been studied as a function of crystal orientation in a constant magnetic field for different values of field and temperature. The anisotropy of the Knight shift has been observed directly for the first time. The linewidth of the resonance has also been studied and the results indicate a contribution to this from indirect exchange interactions. An attempt has been made to observe oscillations in the Knight shift as a function of magnetic field in both tin and aluminum single crystals. None have been detected but an upper limit to the effect has been set and this is compared with theoretical estimates.
A TUBULAR CAPACITOR OF STABLE VALUE
Authors: Kanno M.
Published: April 2011

Very high precision measurements of capacitance have been achieved by recent developments of transformer bridge techniques. Reference capacitors for use with these bridges must be very stable with time and temperature, as well as having other superior characteristics, all of which are very difficult to achieve with the usual mechanical assembly of conductors.This new capacitor uses fused quartz or pyrex glass tubing simply as a support for deposited metallic electrodes, and results in capacitance values of 1 pF which are stable to within one part per million (p.p.m.) for at least six months. They have a temperature coefficient of less than 3 p.p.m./°C, a voltage coefficient of less than 1 p.p.m. for applied voltages from 10 volts to 100 volts, and stability of 1 p.p.m. after free-fall drops from 10-cm heights.It is anticipated that a capacitor of this style will prove to be very useful as a transportable standard of capacitance, and could be used in international comparisons of capacitance values.
A NEW THERMAL NEUTRON FLUX DENSITY STANDARD
Authors: Hargrove C. K. , Geiger K. W.
Published: April 2011

Six Am241–Be(α, n) neutron sources are arranged around the central circumference of a graphite cylinder 28 cm in diameter by 26.5 cm high. This assembly is surrounded by 10 cm of polyethylene. The graphite cylinder contains an accessible central cavity, 5 cm in diameter by 5 cm high, for the calibration of thermal neutron detectors. The thermal neutron flux density in the cavity is measured by 4πβ–γ coincidence counting of irradiated gold foils. A flux density below cadmium cutoff of nthv0 = 8.70 × 103 cm−2 sec−1 (±1.5%) was found. The uniformity is shown to be constant within the cavity to better than ±0.5% over a cylindrical volume 5 cm in diameter by 2 cm high.
LOW-TEMPERATURE NEUTRON IRRADIATION DAMAGE IN ALUMINUM AND GOLD
Authors: Swanson M. L. , Piercy G. R.
Published: April 2011

Fast-neutron irradiation damage at 1.74 °K and its recovery to 100 °K have been investigated in Al and Au by means of residual electrical resistivity measurements. The effects of impurities, quenched-in vacancies, and dislocations were studied. It was found that the damage rate of Al was unchanged by impurity concentrations of less than 0.5 at. % and quenched-in vacancy concentrations of less than 0.002 at. %. Dislocation concentrations of ~2 × 1010/cm2 in Al and ~1011/cm2 in Au increased their damage rates by 35%and 50% respectively. Small amounts of impurity (~0.02 at. %) in Au increased its damage rate by 15% and suppressed the enhancement caused by deformation. The stage I recovery of Al and Au was only slightly increased by extra dislocations, but was increased considerably by quenched-in vacancies. An impurity concentration of ~0.5 at. % suppressed the stage I recovery of Al, but not that of Au. The results are interpreted in terms of channeling in Al and collision chains in Au.
RANGES OF HEAVY IONS IN AMORPHOUS OXIDES
Authors: Domeji B. , Brown F. , Davies J. A. , McCargo M.
Published: April 2011

The range distributions of Na24, Ar41, Kr85, and Xe125 ions in amorphous Al2O3 and WO3 have been measured in the energy interval 0.5 to 160 keV. The experimental technique consisted of measuring the transmission through oxide layers formed anodically on metal foils. The penetrating tail of distributions measured in crystalline targets is found to be absent in amorphous targets. Comparison with the calculations of Lindhard et al. (1963), who assume a random distribution of the target atoms, shows good agreement between theory and experiment.
DIFFUSION IN MULTICOMPONENT METALLIC SYSTEMS: VIII. A KINETIC CALCULATION OF THE ONSAGER L COEFFICIENTS IN SUBSTITUTIONAL SOLID SOLUTIONS
Authors: Lane J. E. , Kirkaldy J. S.
Published: April 2011

Diffusion in multicomponent close-packed solutions is described by means of two transition-state models—a pure interchange model and a pure vacancy model. In the first, the fluxes are given directly in the number-fixed frame of reference, which in dilute solutions may be identified with the volume-fixed frame of reference. In the second, the fluxes are calculated directly in the lattice-fixed (Kirkendall) frame of reference. The fluxes and the kinetically determined L matrix for the second model are transformed to the number-fixed frame for comparison with the first model. In both cases the L coefficients appear in a form to which Onsager's theorem of reciprocal relations is applicable, and all other thermodynamic requirements are satisfied. For dilute solutions the L coefficients are found to vary with composition as[Formula: see text]where the K's are slowly varying coefficients. The K's are always positive for the exchange model, but in exceptional circumstances the Kij may be negative in the vacancy model. The predictions of both models are found to be consistent with some experimental results for diffusion in an almost ideal nonaqueous ternary liquid mixture.Nonzero off-diagonal coefficients in the L matrix of an n component system necessarily arise as a consequence of the dependence between the n fluxes and the applicability of the Gibbs–Duhem relation to the thermodynamic forces. In rich substitutional solutions, these off-diagonal coefficients are nearly always expected to give measurable contributions to the fluxes.
THE SPECTRUM AND STRUCTURE OF THE FREE NCN RADICAL
Authors: Herzberg G. , Travis D. N.
Published: April 2011

A complicated group of bands near 3290 Å appearing in absorption in the flash photolysis of diazomethane has been photographed at high resolution. A detailed rotational analysis of the strongest (0–0) band has shown that the spectrum arises from a 3Πu(inv)–[Formula: see text] transition of the linear symmetric molecule NCN. The triplet fine structures have been resolved for both upper and lower states. The main molecular constants are found to be:[Formula: see text]The upper state shows evidence of Renner-Teller interaction, with a splitting parameter εω2 = −85.7 cm−1. None of the vibration frequencies of the molecule could be determined.
EXPERIMENTAL STUDIES OF THE ANNIHILATION OF POSITRONS IN THE NOBLE GASES
Authors: Falk W. R. , Jones G.
Published: April 2011

The direct annihilation rate of positrons in He, A, and Kr has been studied. Deviation from an exponential for the initial portion of the time distribution of these events is observed and is interpreted as a velocity dependence of the direct annihilation rate. The product of the gas pressure and the width of the non-exponential portion of the time distribution has a value of 270 nsec atm and is approximately independent of the pressure. An estimate of the fraction of positrons forming positronium in argon yields a value of 0.37 ± 0.03. Using this result, a check of the statistical ratio of ortho- to para-positronium formation indicates that 69 ± 7% of the positronium is formed in the ortho state.
ROTATIONAL TEMPERATURES OF THE AURORAL 3914 Å NITROGEN BAND VS. HEIGHT AT CHURCHILL, MANITOBA
Authors: Brandy J. H.
Published: April 2011

Rotational temperatures derived from rapid spectrometric scans of the 3914 Å N2+ band in the aurora have been made over a height range from 93 to 160 km. Simultaneous measurements of heights of lower borders were made using parallactic photography. The temperature range of approximately 190 to 570 °K agrees well with Hunten's profile and tends to confirm the gradient between 110 and 160 km at 5.2°/km.
PROTON CONDUCTION IN LITHIUM HYDRAZINIUM SULPHATE, Li(N2H6)SO4
Authors: Vanderkooy J. , Cuthbert J. D. , Petch H. E.
Published: April 2011

Electrical conductivity measurements have been made over a range of temperatures on single crystals of lithium hydrazinium sulphate. The d-c. conductivity was found to be markedly anisotropic with the direction of easiest conduction along the ferroelectric c axis. The protonic nature of the current carriers was established in an electrolysis experiment in which the evolution of hydrogen gas was found to be, after an initial time lag, directly proportional to the electrical charge transported across the crystal. The conduction process is discussed in terms of crystal structure and proton reorientations.
QUASI-POSITRONIUM IN METALS
Authors: Held A. , Kahana S.
Published: April 2011

A variational search is made for a quasi-bound state of an electron–positron pair in a metal. The basic equation used is the effective Schrödinger equation derived from the electron–positron propagator in an approximation which accurately accounts for the two-body correlations. It is found that no such state exists in metals and hence it can have no influence on the positron annihilation rates. However, the state appears for electron gases of sufficiently low density, [Formula: see text],* and thus determines the low-density annihilation rates.
OPÉRATION D'UN FILTRE DE MASSE QUADRUPOLAIRE EN CONDITION OPTIMUM
Authors: Marchand Pierre , Marmet Paul
Published: April 2011

An alternative method to sweeping masses with a quadrupole mass filter of. constant U/V is suggested. It consists in keeping the relative values of 27 and V such that the absolute resolution ΔA equals 1. The resulting transmission and allowable injection voltages are thereby kept maximum throughout the spectrum, while the resolution obtained is ideally suited for most kinds of mass spectrometric work in atmospheric research. The circuit modifications required can easily be applied to all existing amplitude-swept quadrupole mass filters.
KINETIC EQUATION FOR A HOMOGENEOUS PLASMA IN A UNIFORM MAGNETIC FIELD
Authors: Haggerty M. J. , Sobrino L. G. De
Published: April 2011

The theory of Prigogine and Balescu has been applied to a homogeneous single-species plasma in a static uniform magnetic field. A kinetic equation has been obtained for the one-particle velocity distribution, which is assumed initially isotropic in directions perpendicular to the field. The only stationary solutions of the kinetic equation are the Maxwellian equilibrium distributions, and an H theorem has been established. The neglect of "collisions" of the order of duration of one cyclotron period or less (a strong magnetic-field approximation) modifies the kinetic equation so that it no longer predicts any relaxation of the velocity components parallel to the magnetic field. The assumptions and approximations of the theory are stated, and are discussed in some detail.
ANGULAR DISTRIBUTIONS AND ENERGY SPECTRA OF ELECTRONS ASSOCIATED WITH AURORAL EVENTS
Authors: McDiarmid I. B. , Budzinski E. E.
Published: April 2011

A number of Black Brant II rockets containing various charged-particle detectors have been fired during 1963 and 1964 from Fort Churchill, Manitoba. Most of the firings took place at times of auroral events and the rocket instrumentation was designed to study the particles associated with these events.Pitch-angle distributions have been observed for electrons with energies greater than 40 keV, which show varying degrees of isotropy in the pitch-angle range 0° to 90°. In no case has a distribution been observed in which the intensity increased towards small angles. In some cases electron-intensity changes appear to be correlated with changes in spectrum and angular distribution, while in other cases changes in these quantities do not appear to be related.The particle intensity measurements are used along with radio-frequency probe measurements of electron density to infer values for the nighttime recombination coefficient in the D region of the ionosphere.
HIGH-FREQUENCY SCATTERING FROM A COATED CYLINDER
Authors: Uslenghi P. L. E.
Published: April 2011

The scattered field produced by a plane electromagnetic wave incident on an infinitely long imperfectly conducting cylinder coated with a layer of material with complex index of refraction is considered. The geometric optics and the creeping wave contributions to the backscattered field are obtained, for normal incidence and small wavelengths.
VARIATION IN HEIGHTS OF THE LOWER BORDERS OF AURORAL BANDS
Authors: Brandy J. H.
Published: April 2011

The variation in height of 20 well-defined auroras has been measured over projected distances from 70 to 401 km. Differences in height as large as 55 km have been found between two points on the lower borders of a band. Half the auroras measured showed relatively small variations, the other half considerable. These facts may need to be taken into account in the use of single-station photographs of bands for determining auroral properties such as heights and widths.
THE EFFECTIVE ANTENNA BEAM WIDTH FOR A SATELLITE-BORNE RADIO TELESCOPE
Authors: Hartz T. R. , Roger R. S.
Published: April 2011

For an antenna in the ionosphere above the F layer, there is a cone of directions within which a radio signal coming in to the earth can reach the antenna. Computations have been carried out of the aperture of this conical pattern for an antenna height of 1000 km, and for different ionospheric conditions. The computations are compared to experimental determinations of the aperture made using the sweep-frequency receiver in the Alouette satellite to observe the radiations from the sun.
ROTATIONAL FINE STRUCTURE OF THE 3Π STATE OF PF
Authors: Kovács I.
Published: April 2011

An investigation has shown that the 3Π state observed in the 3Π–3Σ transition of the PF molecule deviates from the known triplet formula. By taking into account both the spin–spin interaction and the perturbation of the 3Π state by 1Π states, this anomalous multiplet splitting can be interpreted. From the newly derived equations, accurate values of the rotational constants (B and D) and the multiplet splitting constants (A) have been derived for the ν = 0 and ν = 1 levels of the 3Π state.
IONIC CONDUCTIVITY OF POTASSIUM BROMIDE CRYSTALS
Authors: Rolfe J.
Published: April 2011

The conductivity of single crystals of potassium bromide has been measured as a function of temperature. Potassium carbonate was found to be sufficiently soluble at high temperatures in KBr to cause a conductivity due to negative ion vacancies. The ionic conductivity parameters of KBr were calculated from conductivity measurements on crystals containing known concentrations of potassium carbonate and calcium bromide without recourse to transport number experiments. A simple theory of association was found to be adequate to describe the interaction between calcium ions and positive ion vacancies. The solubility of free divalent impurities in KBr was also calculated from conductivity measurements. The following enthalpy values were found: for formation of a pair of Schottky vacancies, 2.53 eV; for the motion of positive ion vacancies, 0.665 eV; for the motion of negative ion vacancies, 0.87 eV; for the association of calcium ions and positive ion vacancies, 0.46 eV.
THE EFFECT OF STRAIN ON THE EXCITON SPECTRUM OF GERMANIUM
Authors: Glass A. M.
Published: April 2011

The intensity of optical absorption, near the absorption edge in germanium, is examined as a function of strain applied to the lattice at 90 °K. The results are interpreted in terms of the change of the band structure of the lattice with applied strain. The absorption edge in unstrained germanium shows a single sharp peak due to direct-transition exciton formation at k = 0, whereas the edge in the strained specimens shows two exciton peaks. The peak positions vary linearly with both compressional and tensional strain up to the maximum strains applied (0.1% deformation). The exciton binding energies in the strained germanium lattice, calculated within the effective mass approximation, are approximately equal and independent of the magnitude of the strain. The separation of the peaks gives for the shear deformation potentials the values |b| = (2.7 ± 0.3) eV/unit (100) shear and |d| = (4.7 ± 0.5) eV/unit (111) shear. The positions of the peaks give the shift of the energy gap as −(10.3 ± 1) eV/unit dilation.Lattice imperfections are found to have no effect on the interpretation of the results.
LIFETIMES OF THE LOW-LYING LEVELS OF 20Ne
Authors: Evans H. C. , Eswaran M. A. , Gove H. E. , Litherland A. E. , Broude C.
Published: April 2011

The lifetimes of the 1.63-, 4.25-, 4.97-, and 5.63-MeV levels in 20Ne have been measured by the Doppler shift attenuation method. The lifetimes in picoseconds are 1.23 ± 0.12, 0.134 ± 0.012, [Formula: see text], and 0.35 ± 0.075 respectively. The reduced widths in Weisskopf units for the 1.63-, 2.62-, 3.34-, and 4.00-MeV gamma-ray transitions, together with the gamma-ray multipolarities, are [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text].
EQUILIBRIUM FRACTIONS FOR A HYDROGEN-ION BEAM (10–50 keV) IN 17 GASES AND VAPORS
Authors: Wittkower A. B. , Bastide R. P. , Brooks N. B. , Rose P. H. , Hopwood L.
Published: April 2011

The equilibrium fractions for a hydrogen-ion beam have been measured, from 10 to 50 keV, in the following gases or vapors: hydrogen (H2), helium (He), nitrogen (N2), oxygen (O2), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), nitrous oxide (N2O), deuterium (D2), water vapor (H2O), ammonia (NH3), methane (CH4), sulphur hexafluoride (SF6), butane (C4H10), 2,2-dimethylpropane (C5H12), carbon dioxide (CO2).
ELASTIC SCATTERING OF ALPHA PARTICLES BY OXYGEN FOR INCIDENT ENERGIES BETWEEN 7.2 AND 8.5 MeV
Authors: McCallum G. J. , Ferguson A. J.
Published: April 2011

Angular distributions of α particles elastically scattered by 16O, obtained at 12 energies between 7.4 and 8.5 MeV, are presented together with the yield of scattered α particles measured by fixing the detectors at a given angle and varying the energy of the incident particles. Four such excitation curves in the energy-range 7.2–8.4 MeV are presented. Resonances are observed at energies 7.32, 7.66, 7.89, and 8.28 MeV. Tentative spin and parity assignments of 4+ and 2+ are obtained for the 7.89- and 8.28-MeV resonances.
BINARY CORRELATION FUNCTION FOR A HOMOGENEOUS PLASMA IN A UNIFORM MAGNETIC FIELD
Authors: Haggerty M. J.
Published: April 2011

Previous work on the application of the theory of Prigogine and Balescu to a homogeneous single-species plasma in a static uniform magnetic field has been extended. An equation for the binary correlation function has been obtained in terms of the one-particle velocity distribution, which is in turn determined by the kinetic equation previously derived. Equations for the binary spatial correlation function and the binary correlation function for the guiding centers have also been obtained. It is demonstrated that the binary spatial correlation function represents the well-known Debye-screened equilibrium correlations when the one-particle velocity distribution is the equilibrium distribution.
AMPLITUDE-MODULATED END-FIRE ARRAY
Authors: Nagai K.
Published: April 2011

The directivity formula of a very long end-fire array made up of a continuous line of isotropic radiators is derived, assuming a sine-modulated current amplitude along the axis and constant phase difference from element to element.Sample calculations are given for an array of 40 wavelengths. The directivity of the array is found to depend on the phase velocity and the modulation coefficient; and the optimum directivity of this array is found to be greater than that of a Hansen–Woodyard array of the same length.
THE COEFFICIENT OF THERMAL EXPANSION OF VARIOUS CUBIC METALS BELOW 100 °K
Authors: Fraser D. B. , Hallett A. C. Hollis
Published: April 2011

Measurements have been made of the coefficient of linear thermal expansion, α, of Cu, Ag, Au, Al, α-Fe, and Ni at temperatures below 100 °K using an interferometric method in which the spacer between the optical flats of a Fabry–Perot-type interferometer was made of the material studied. The lowest temperatures at which values of α are given are about 20 °K (Cu, Ag), 11 °K (Au), 25 °K (Al, Fe), and 32 °K (Ni). The results are discussed in terms of the Gruneisen parameter γ which, for Cu, Ag, and Au, is approximately constant at high temperatures, but tends to rise slightly as the temperature is reduced towards the lowest temperatures of measurement. For Al, a correction for the electronic contribution is applied below 40 °K to deduce the lattice contribution γL, which rises more spectacularly at low temperatures than the results for the noble metals. For Fe, separation of α into two contributions, one from the lattice and one from the combined magnetic and electronic effects, may be made, giving γL = 1.45; the combined magnetic and electronic contribution is very small.
A GENERALIZATION OF THE RASETTI AND SLATER METHODS FOR DETERMINING THE EIGENVALUES AND EIGENFUNCTIONS FOR A GIVEN ATOMIC FIELD
Authors: Tietz T.
Published: April 2011

This paper follows up the work of Rasetti and Slater and has the purpose of giving the eigenvalues and eigenfunctions of electrons for a given atomic field.
SOME LOW-ENERGY ATOMIC STOPPING CROSS SECTIONS
Authors: Ormrod J. H. , Macdonald J. R. , Duckworth H. E.
Published: April 2011

The electronic stopping cross sections for protons in aluminum are reported in the energy interval 10 < E < 70 keV. Stopping cross sections below 150 keV in carbon targets for projectiles with [Formula: see text], and in aluminum targets for [Formula: see text] are reported also. The results are compared with theory and show reasonable agreement. The previously reported periodic dependence of Se on the atomic number of the projectile is also evident in the present results.
ANOMALOUS ROTATIONAL LINE INTENSITIES IN ELECTRONIC TRANSITIONS OF POLYATOMIC MOLECULES: AXIS-SWITCHING
Authors: Hougen J. T. , Watson J. K. G.
Published: April 2011

It is convenient when performing calculations on a vibrating and rotating molecule to define an axis system which is somehow fixed to the molecule. The orientation of the usual molecule-fixed axis system, however, depends not only upon the instantaneous positions of the nuclei, but also upon the equilibrium positions from which the nuclei are regarded as being displaced. Thus, when a molecule of low enough symmetry undergoes an electronic transition accompanied by a change in geometry, it will, in general, be necessary to consider two molecule-fixed axis systems, corresponding to the two different electronic states. This change in axis system from one electronic state to another will be called axis-switching. The two axis systems can be related to each other by the 3 × 3 rotation matrix which brings them into coincidence. The elements of this matrix are functions of the equilibrium geometries of the two electronic states as well as of the instantaneous positions of the atoms in the molecule. Axis-switching leads to departures from the usual expressions for the intensities of rotational lines, the effects of which are most noticeable in near-symmetric tops. The forbidden subbands occurring in the 2 400 Å system of acetylene can be satisfactorily explained by axis-switching. Axis-switching effects may also be present in the spectra of HCN, HSiCl, and HSiBr.
PHOTOALPHA REACTIONS IN 12C AND 16O BELOW 17 MeV
Authors: Roalsvig Jan P.
Published: April 2011

Yield and cross-section curves have been obtained for the reactions 12C(γ, 3α), 16O(γ, 4α), and 16O(γ, α)12C from 12 to 17 MeV, by irradiating nuclear emulsions in the beam from the University of Saskatchewan betatron.
QUASI-SPIN TREATMENT OF JOSEPHSON TUNNELING BETWEEN SUPERCONDUCTORS
Authors: Wallace P. R. , Stavn M. J.
Published: April 2011

It is shown that the quasi-spin method in superconductivity permits a simple and direct calculation of the effects (which were first discussed by Josephson) associated with tunneling of electron pairs between superconductors across an insulating junction.
CONSTITUTION AND MAGNETIC AND ELECTRICAL PROPERTIES OF PALLADIUM TELLURIDES (PdTe–PdTe2)
Authors: Kjekshus A. , Pearson W. B.
Published: April 2011

The region from PdTe to PdTe2 has been examined by X-ray methods to establish the phase boundaries. The results confirm the existence of a continuous solid solution at high temperatures and narrow homogeneity regions for PdTe and PdTe2 at low temperatures. PdTe is a nonstoichiometric phase, at least below 500 °C. Magnetic susceptibility, electrical resistivity, thermoelectric power, and superconducting transition temperatures of PdTe and PdTe2 have been measured.
GEOMAGNETIC AND IONOSPHERIC OBSERVATIONS ASSOCIATED WITH AURORAL ACTIVITY DURING THE TOTAL SOLAR ECLIPSE OF JULY 20, 1963
Authors: Clark T. A. , Anger C. D.
Published: April 2011

Data obtained at Fort Providence, N.W.T., Canada, during the total solar eclipse of July 20, 1963, indicate that during most of the partial eclipse there was a moderate degree of auroral activity. This activity became slight during the period of totality and no auroral luminosity was detected. Electron precipitation was indicated by an enhancement of the intensity of X rays of energy greater than 9 keV at balloon altitudes and by small amounts of cosmic-noise absorption. A small but irregular increase in cosmic-noise level at 30 Mc/s, which was greater than 0.2 dB at totality, was recorded. It was concluded that the irregularity was caused by small amounts of superimposed auroral absorption.
ACOUSTICAL MOTION IN A SEMICONTINUOUS PLASMA
Authors: Frood D. G. H.
Published: April 2011

In many plasmas, the electron temperature is so high compared to the ion temperature that the electrons may be treated as a "collsionless" medium. Often, however, the mean free path for the ions is so small that the motion of these particles is dominated by the short-range "collisional" forces. Assuming a hydrodynamical model for the ions and rarefied conditions for the electrons, we discuss in this paper the linearized collective modes of such semicontinuous plasmas.The high-frequency oscillations are practically identical with those obtained in the rarefied theory (Frood 1963a), but for very long wavelengths the Landau (or electronic) contribution to the optical damping is negligible compared with the viscous (or ionic) damping. Similarly, for the acoustic modes the speed of sound is practically the same as in the rarefied case, but even at fairly short wavelengths the viscous contribution to the sonic damping outweighs the collisionless contribution.Comparison of the theories of acoustic damping in semicontinuous and rarefied plasmas indicates a convenient means of determining to what extent a plasma is behaving in a collision-free or a collision-dominated manner. Recent experiments at Princeton—performed simultaneously with, but independently of, the present theoretical predictions (Frood 1963b)—have done much to verify this contention.
LABORATORY INVESTIGATIONS OF THE INTERSTELLAR RADIO-FREQUENCY LINES OF CH AND OTHER MOLECULES
Authors: Douglas A. E. , Elliott G. A.
Published: April 2011

The 0–0 band of the 2Δ–2Π transition of CH has been remeasured from high-dispersion plates and more precise values of the Λ doubling in the 2Π state have been determined. From these optical measurements, the transition between the two components of the lowest rotational level can be predicted to lie at 3 400 Mc/sec. The possibility of finding CH and also other molecules in interstellar space by radio-frequency astronomical observations is discussed.
TEMPERATURE EFFECTS IN THE PHOTOCONDUCTIVITY OF HIGH-RESISTANCE Cu2O
Authors: Weichman F. L. , McInnis B. C.
Published: April 2011

Measurements were made at a number of different wavelengths to find the temperature dependence of the photoconductivity in Cu2O of resistivity greater than 108 ohm-cm between +100 °C and −100 °C. A number of features of this temperature dependence are discussed with particular reference to making a-c. measurements on a slowly responding photoconductor. It is shown that as the chopping period becomes short in comparison with the response time of the photoconductor, the r.m.s. photoconductivity will decrease linearly with the chopping period for three different types of response considered. Photoresponse at room temperature was also measured on Cu2O after two methods of vacuum annealing, one at 1 000 °C and the other at 300 °C. The former shows a sensitivity only for wavelengths less than 0.6 μ, whereas the latter shows the more usual behavior of a peak near 0.6 μ, with sensitivity measurable well into the near infrared.
THERMAL EXPANSION, GRUENEISEN PARAMETER, AND TEMPERATURE DEPENDENCE OF LATTICE VIBRATION FREQUENCIES OF ALUMINUM OXIDE
Authors: Schauer Alois
Published: April 2011

The linear thermal expansion coefficient of polycrystalline aluminum oxide has been measured in the temperature range from 100 °K to 1 500 °K by an interferometric method. The interferometer used is capable of giving high accuracy over a wide range of temperatures, and is described in some detail. The Grueneisen parameter of aluminum oxide is calculated and found to be 1.35 ± 0.05 over the whole temperature range. There is no significant change, such as might be expected from theory, of the Grueneisen parameter around 0.2 × Debye temperature. Based on the formulae given in an earlier publication, the temperature dependence of lattice vibration frequencies of aluminum oxide is calculated.
THE INFRARED SPECTRUM OF CARBON MONOXIDE IN CO–He MIXTURES AT HIGH PRESSURES
Authors: Armstrong R. L. , Welsh H. L.
Published: April 2011

The 1–0 and 2–0 infrared bands of carbon monoxide were measured in CO–He mixtures at pressures up to 3 000 atm at 295 °K. Extrapolation of the integrated intensities of the bands gave the absolute intensities, Γ01 = 2 686 ± 44 and Γ02 = 9.29 ± 0.27 cm2 per mole. A slight increase in the band intensities with pressure is due to apparent induced absorption. A moment analysis of the bands, as proposed by Gordon, shows the presence of a torque due to intermolecular forces which hinders the molecular rotation; the magnitude of the torque derived from the analysis varies linearly with the density of the perturbing gas.
FICTON THEORY OF DYNAMICAL SYSTEMS WITH NOISY PARAMETERS
Authors: Bourret R. C.
Published: April 2011

The theory of randomly perturbed waves described previously (Bourret 1962a, b) is presented in a form applicable to purely time-dependent systems, classical or quantum mechanical. It is then applied to the problem of a spin-[Formula: see text] dipole in a magnetic field with random fluctuations. One- and two-ficton processes are taken into account and a "renormalization" approximation is given also. Graphical comparison of the approximate solutions with the exact solution is presented. As a classical example, the harmonic oscillator with a noisy frequency parameter is analyzed in both the one- and two-ficton approximations.
THE EFFECT OF FINITE CONDUCTIVITY ON GRAVITY WAVES IN A HORIZONTAL MAGNETIC FIELD
Authors: Wentzell R. A. , Blackwell J. H.
Published: April 2011

A study has been made of the behavior of the plane interface between a vacuum and an electrically conducting fluid subject to a normal gravitational force and a magnetic field parallel to the interface. The system is examined for perturbations which bend the lines of force, without restriction to the extensively used idealization of infinite electrical conductivity. The eigenvalue spectra obtained, which are surprisingly different from the simpler ones corresponding to infinite conductivity, are examined by approximate and numerical techniques over the complete range of electrical conductivity from infinity to zero. The disappearance of a normal mode solution above a critical value of conductivity is an interesting feature of the effect of finite conductivity on magnetohydrodynamic stability.
THERMOELECTRIC PROPERTIES OF Bi2Te3–Sb2Te3 ALLOYS
Authors: Champness C. H. , Chiang P. T. , Parekh P.
Published: April 2011

Alloys of nominal composition Bi2−xSbxTe3+y were prepared in an evacuated, sealed ampule by a horizontal zone melting method. Single-crystal samples were cut from the ingots, and measurements of Seebeck coefficient, electrical conductivity, thermoelectric figure of merit (Z), and thermal conductivity (κ) were made over a temperature range of 160 to 360 °K using the Peltier–Seebeck method developed by Harman. Alloys of nominal composition Bi2−xSbxTe3.13 were found to be n type for [Formula: see text] and p type for x > 1. In alloys of high antimony content, the hole concentration was influenced very little by the amount of excess tellurium. The change of Z was studied by varying y from 0.06 to 0.26 at x equal to 0, 0.25, 1.4, 1.5, and 1.6 respectively. Optimum doping to maximize Z did not appear to be possible in a simple way over the entire range of x between 0 and 2. The temperature dependence of κ indicated that the maximum Z at x = 1.5 may be limited by an ambipolar contribution.
SOME OBSERVATIONS OF TYPE-B RED AURORA WITH A MULTICHANNEL PHOTOMETER
Authors: Evans W. F. J. , Jones A. Vallance
Published: April 2011

A five-channel interference filter photometer was used to make observations of the relative brightnesses of the First Positive Group N2 bands, the λ-3 914 N2+ band, the λ-5 577 [OI] line, and the First Negative O2+ bands in type-B red aurora. It was found that the time delay between the emission of the 1NG N2+ bands and the 1PG N2 bands was less than 0.1 second in disagreement with the O2−/N2+ charge neutralization mechanism for the enhancement of the First Positive Group bands.The lifetime of the O(1S) atoms emitting the green line was determined by the method of Omholt (1959) by comparing fluctuations in the emission of the green line with those of the N2+ bands. In type-B red aurora it was found that this lifetime corresponded to 0.48 ± 0.06 second as compared with 0.67 ± 0.06 second in normal aurora. This may indicate that collisional deactivation of the O(1S) state occurs in type-B red aurora and is one factor contributing to the reddening.The relative brightness measurements showed, for type-B red aurora compared with normal aurora, an appreciable intensification (~50%) of the 1PG emission compared to the 1NG N2+ bands. At the same time there was observed an average decrease of about 30% in the intensity of the green line compared to the 1NG bands.
PRESSURE-INDUCED INFRARED ABSORPTION OF GASEOUS HYDROGEN AND DEUTERIUM AT LOW TEMPERATURES: I. THE INTEGRATED ABSORPTION COEFFICIENTS
Authors: Watanabe A. , Welsh H. L.
Published: April 2011

The pressure-induced infrared absorption of the fundamental band of hydrogen, in the pure gas and in a H2–He mixture, and of deuterium was studied in the temperature range from 18 °K to 77 °K. Path lengths up to 13.6 m at 1 atm or somewhat higher were obtained in a multiple-traversal cell cooled by liquid hydrogen or nitrogen. The binary coefficient [Formula: see text] for hydrogen shows a rise at low temperature, indicating the existence of bound states predicted by theory for the (H2)2 complex. The effect is more pronounced for deuterium. For the H2–He mixture [Formula: see text] decreases monotonically with temperature, thus showing no evidence of bound states for H2–He pairs. Fine structure at the maxima of the pressure-induced band in hydrogen and deuterium gives direct spectroscopic evidence of bound states of (H2)2 and (D2)2 complexes at low temperatures.
THE DIFFUSION OF A HIGHLY IONIZED PLASMA ACROSS A MAGNETIC FIELD
Authors: Olson O. D. , Skarsgard H. M.
Published: April 2011

The decay of electron density and temperature has been measured in a low-pressure helium afterglow by means of double floating probes of very small collection area. The plasma was contained in a glass toroidal chamber; initial gas pressures were in the vicinity of 0.030 Torr. Magnetic confining fields from 0.004 to 0.0860 Wb/m2 were used and the degree of ionization was such that coulomb collisions were dominant. Strict criteria were adopted to ensure reliable operation of the double probes. A theory of diffusion is presented which includes interactions between all species of particles. Drift effects due to the inhomogeneous magnetic field are important at the higher field strengths and are taken into account. Reasonably good agreement is found between the theoretical and observed time constants for electron-density decay over a wide range of experimental conditions.
ANGULAR DISTRIBUTIONS IN GAMMA–ALPHA REACTIONS IN THE NUCLEI OF NUCLEAR EMULSIONS
Authors: Roalsvig Jan P.
Published: April 2011

The angular distribution for alpha particles produced by (γ, α) reactions in the nuclei of nuclear emulsions has been measured. For the reaction 16O(γ, α)12C, in which the 12C nucleus is left in its ground state (J = 0+, T = 0), through an excited state at 12.5 MeV in 16O, the angular distribution is in agreement with a mixture of E1 and E2 interactions, with an E2/E1 intensity ratio of 0.50. For the same reaction, through an excited state at 14.3 MeV in 16O, the angular distribution is best represented by a pure E2 interaction.
POLARIZATION OF ELASTICALLY SCATTERED 1.33-MeV PHOTONS
Authors: Williams R. A. , McNeill K. G.
Published: April 2011

Measurements have been made as a function of angle of the polarization of 1.33-MeV gamma rays elastically scattered by lead. The analysis of the experimental data included the contribution of the L-shell electrons to inelastic Compton scattering. The results show no apparent deviation from the polarizations expected on the basis of Rayleigh and Thomson scattering.
A METHOD OF DETERMINING THE REVERSAL TEMPERATURES IN AN EXCITED GAS
Authors: Nodwell R. A. , Irwin J. C.
Published: April 2011

A method of determining the reversal temperatures, the relative population densities, and the total absorption in highly excited and ionized gases is described. Measurements of the reversal temperatures of the lines emitted by a neon glow discharge are reported. The distribution of population densities of the excited states is shown to depart radically from a Boltzmann distribution.