bluuebunny/crossref_metadata_2025 huggingface dataset:
HIGH PULSED FIELD MAGNETORESISTANCE IN INDIUM ANTIMONIDE AND INDIUM ARSENIDE
Authors: Champness C. H.
Published: April 2011

Measurements of transverse magnetoresistance have been made using pulsed fields up to about 300 kilo-oersteds on oriented single-crystal samples of near-intrinsic indium antimonide and extrinsic indium arsenide at room temperature. At the maximum field, about a 400-fold resistivity increase was found in indium antimonide and about a 4-fold increase in indium arsenide. The variation with field can largely be accounted for by classical two-carrier conduction theory, even though ħωc/kT > 1 and [Formula: see text] for the electrons in indium antimonide. At the lower fields in indium antimonide the individual bands alone give no measurable contribution to the magnetoresistance, indicating that for the electrons at least, the relaxation time must be almost independent of energy. While no strong evidence of Landau quantization effects was apparent, the magnetoresistance values at the higher fields in general fell below the classical theoretical curve. This could be interpreted as a variation of the electron mobility at high fields such that approximately [Formula: see text].
THE SPIN OF THE 3.70-MEV LEVEL IN Al25
Authors: McCallum G. J.
Published: April 2011

The 3.70-Mev level in Al25 has been studied by means of the reaction Mg24(p, γ)Al25 at the 1.49-Mev resonance. Direct angular distribution measurements of the de-excitation gamma radiation support the spin assignment of 7/2− for this level. An E2/M1 amplitude mixing ratio of −0.55 ± 0.2 is found for the 1.79-Mev de-excitation radiation from the fourth excited state to the ground state of Al25. The ratio of the reduced transition probability of the E2 radiation from the 1.79-Mev level to the first excited state is shown to be ~30 times that to the ground state. This result provides further confirmation of rotational band structure in Al25 since the collective model predicts such an enhancement of E2 transitions between rotational bands whereas cross-band transitions are not expected to be enhanced.
THE DECAY OF Ba133
Authors: Mann K. C. , Chaturvedi R. P.
Published: April 2011

The electron-capture decay of Ba133 and the subsequent de-excitation of Cs133 have been investigated with magnetic and scintillation spectrometers. The measured conversion coefficients and transition intensities lead to the following spin assignments for the states of Cs133: ground, 7/2+; 81 kev, 5/2+; 161 kev, 5/2 +; 383 kev, 3/2+; and 437 kev, 1/2+. The multipolarities of the connecting transitions are: 54 kev (M1), 80 kev (M1), 81 kev (M1), 161 kev (M1+E2), 276 kev (E2), 302 kev (M1+E2), 356 kev (E2), and 383 kev (E2). The limits of experimental error in the measured conversion coefficients do not exclude the possibility that the 437-kev level is 3/2+ and that both the 276- and 356-kev transitions are M1 + E2 admixtures.
NEW OBSERVATIONS ON THE SWAN BANDS OF C2
Authors: Callomon J. H. , Gilby A. C.
Published: April 2011

The molecular spectra emitted by flash discharges of short duration through carbon dioxide gas are wholly those of C2, the Swan system predominating. Rotational structure extends to very high quantum numbers, and numerous small perturbations, some reported previously, are prominent. Eleven of these in the levels ν = 0–2 of the A3Πg state are discussed; eight are shown to arise through interactions with the recently described [Formula: see text] state.
HEAT FLOW IN A SYSTEM OF CYLINDRICAL SYMMETRY
Authors: Jessop A. M.
Published: April 2011

Numerical values of two heat flow integrals have been obtained by means of a digital computer. Expressions have been obtained for the temperature of, and the heat flow from, a mass having a resistive internal boundary, and a boundary temperature varying sinusoidally with time.
CONDUCTION AND ELECTROLYSIS IN CELLULOSE
Authors: Murphy E. J.
Published: April 2011

Dry cellulose conducts in accordance with the theoretical expression for the temperature dependence of ionic conductivity. The appearance of products of electrolysis in approximate agreement with Faraday's law and the presence of gaseous hydrogen as the main component indicate that the conduction is ionic (rather than electronic, as in organic semiconductors), and that it depends upon the migration of protons and proton holes. It is proposed that conduction in dry cellulose involves tunneling of the proton between equivalent sites, the one in the ion, the other in an adjacent neutral molecule. Resonance tunneling occurs when these structures are in suitable mutual configurations. This occurs with a frequency given by a Boltzmann factor. Experiment indicates that the energy in this factor is 10.6 kcal/mole. As this is about twice the energy of the hydrogen bond, it is proposed that the energy of activation for mobility represents the simultaneous breaking of two hydrogen bonds in bringing adjacent structures into suitable configuration for resonance tunneling. The results are considered to exhibit an example of an organic dielectric which conducts by the transport of protons at a rate depending upon an activation energy due to the breaking of hydrogen bonds.A small dependence of the molar yield of gas per Faraday on the applied voltage gradient was observed. Its significance is discussed in terms of a generalization of the electrode process to include effects of field emission as the voltage gradient approaches the breakdown level.
THE THICKNESS OF MOVING HELIUM II FILM
Authors: Gribbon P. W. F. , Jackson L. C.
Published: April 2011

The thickness of moving liquid helium II films has been measured using the polarized light method developed by Burge and Jackson. The moving film was that on the outside of a cylindrical stainless steel beaker emptying by creep at the rate corresponding to the temperature for the two cases 1.68° K and 1.83° K. Measured at a height of 1 cm above the outer level of the liquid the thicknesses were 5.6% and 4.5% less than those of the stationary film at 1.68° K and 1.83° K respectively. The observations are compared with the theoretical expressions for the difference in thickness of stationary and moving films derived by Kontorovich and by Franchetti.
KINETIC EQUATION DESCRIBING IRREVERSIBLE PROCESSES IN IONIZED GASES, II
Authors: Rosenberg R. L. , Wu Ta-You
Published: April 2011

In a previous paper, the authors formulated the theory of irreversible processes in a spatially inhomogeneous plasma on the basis of Bogoliubov's theory as extended by Guernsey and Uhlenbeck. The kinetic equation, in terms of g(κ, n, t), the Fourier transform of the spatially inhomogeneous part f(r, n, t) of the one-particle distribution function F(r, n, t), has been obtained to the first order in 4πe2, all orders in (4πe2/ν), and the first order in κ which is related to the spatial inhomogeneity. In the present work, the mathematical part of the previous paper, especially the expansion in various orders in κ, has been revised. The kinetic equation is given in (33), in which are exhibited: (a) the stream term; (b) the corrections to the stream term arising from the "collisions"; (c) the Vlasov term; (d) the corrections, in the zeroth and the first order in κ, to the Vlasov term depending not only on the "static" effective field but also on the divergence of the mean current, these corrections being momentum-dependent and time-irreversible in nature; (e) the main "collision integral" which is time-irreversible, in the zeroth and the first order in κ.
ANALYSIS OF THE OUTPUT OF ROCKET-BORNE MAGNETOMETERS*
Authors: Ito M.
Published: April 2011

The output of rocket-borne magnetometers is analyzed for assumed simple angular motions of the magnetometer frame of reference. Calculated output records are given and a qualitative analysis is made by referring to a simple pictorial model for the magnetometer output pattern.
GAMMA-ACTIVE FALLOUT NEAR TORONTO IN 1961–1962
Authors: Mohindra V. K. , Harrison J. E. , Trojan A. D. , McNeill K. G.
Published: April 2011

Results are given of measurements of the Cs137 activity in the human body, milk, and air over a two-year period. They show that after a continuing decrease in activity since 1959, the levels of Cs137 in the biosphere have taken a sharp rise since the fall of 1961. The latest figure for the Cs137 burden in man is 10−2 μc, one three-thousandths of the occupational maximum permissible burden.
ZEEMAN EFFECT DATA FOR SINGLY IONIZED LUTETIUM
Authors: Pinnington E. H.
Published: April 2011

Zeeman patterns are listed for the Lu II lines at 2969.8, 3198.1, 3254.3, 4184.2, 5476.7, and 6611.7 Å. These results are used to determine the g factors for the levels at 11796, 14199, 17332, 32453, 41225, 44919, and 45458 cm−1.
GROWTH OF MUTUAL FRICTION IN LIQUID HELIUM II
Authors: Bhagat S. M. , Critchlow P. R.
Published: April 2011

An explanation is offered to account for the fact that two propagation velocities of turbulence—one in either direction—may be observed when a heat current is applied to a long, narrow channel containing liquid helium II. The theory also gives qualitatively the correct dependence of the velocities on temperature and heat current.
THE REACTOR NEUTRON CAPTURE CROSS SECTION OF Ag110m
Authors: Hart R. G. , Graham R. L.
Published: April 2011

Natural silver has been irradiated for 75.3 days in a thermal neutron flux of 2.42 × 1014 cm−2 sec−1 and the complex beta-ray spectrum of the resulting activities of 249-day Ag110m and 7.5-day Ag111 have been studied with a magnetic spectrometer. From the measured ratio of the respective beta-ray intensities and using the currently accepted decay schemes of these nuclides a value of 82 ± 11 barns is obtained for the reactor neutron capture cross section of Ag110m. Possible causes of systematic error are discussed.
SATELLITE MEASUREMENTS IN THE "STARFISH" ARTIFICIAL RADIATION ZONE
Authors: McDiarmid I. B. , Burrows J. R. , Budzinski E. E. , Rose D. C.
Published: April 2011

Particle detectors in the Alouette satellite have been used to study radiation artificially injected into the earth's magnetic field by the "Starfish" high-altitude nuclear explosion. The spatial distribution of electrons with energies greater than 3.9 Mev is given for a time about three months after the explosion for regions in BL space sampled by the satellite. The measurements show that the electron spectrum is a strong function of the magnetic shell parameter L; in the range L = 1.25 to 1.70 there is a marked softening of the spectrum with increasing L. The decay of the artificial radiation zone has been studied for a period of from three to six months following the explosion, and decay constants at different points in BL space have been estimated.
THE EFFECT OF PRESSURE ON THE ELECTRICAL RESISTANCE OF LITHIUM
Authors: Gugan D.
Published: April 2011

The change of resistance of lithium with hydrostatic pressure has been studied at low temperatures. Anomalous results have been found at all temperatures. The pressure coefficient of residual resistivity of dilute alloys of magnesium in lithium has been found to depend on the structure of the parent lattice.
BREAKDOWN OF A RADIO-FREQUENCY DISCHARGE IN A NONRESONANT MAGNETIC FIELD
Authors: Sen S. N. , Ghosh A. K.
Published: April 2011

The breakdown of a radio-frequency discharge excited by a radio-frequency voltage of frequency lying between 7 and 10 Mc/sec has been studied in a cylindrical discharge tube (length 10 cm) in air and in nitrogen with the pressure varying between 10 and 300 μ, in the presence of a nonresonant magnetic field varying from 0 to 80 gauss. The breakdown voltage is found to be greater than when no magnetic field is present for all values of pressure, and the pressure at which the breakdown voltage becomes minimum increases with the application of the magnetic field. Kihara's theory regarding radio-frequency discharge (1952) has been modified by the introduction of effects due to the magnetic field, and a new expression for the breakdown voltage and the pressure at which the breakdown voltage becomes minimum has been deduced. The new expression explains the observed results, and the quantitative disagreement has been ascribed to the uncertainty in the numerical values of the molecular constants introduced by Kihara in his theory. The effect of attachment in the case of air has been calculated within some limitations and it has been observed that when attachment is taken into consideration, the calculated theoretical values are in better agreement with the observed experimental results.
STRAIN RATE DEPENDENCE OF THE FLOW STRESS IN CADMIUM CRYSTALS
Authors: Davis K. G.
Published: April 2011

The strain rate dependence of the flow stress in cadmium crystals of 99.9 and 99.9999% purity tested in tension at 77° K has been investigated. A Cottrell–Stokes Δτ–τ relationship is fairly closely followed, with a change in slope at a stress corresponding to the end of the linear region of glide. The change in slope is much less pronounced in the lower-purity material.
NEUTRON SEPARATION ENERGIES FOR TELLURIUM AND THE I130–Te130 AND Te123–Sb123 DECAY ENERGIES
Authors: Barber R. C. , McLatchie W. , Bishop R. L. , Rookhuyzen P. Van , Duckworth H. E.
Published: April 2011

Values derived from mass spectral doublets are reported for the following mass differences: Te124−Te122, Te125−Te123, Te126−Te124, Te128−Te126, and Te130−Te128. The double neutron separation energies for Te124, Te126, Te128, and Te130 are found to exhibit a strikingly regular behavior. Single neutron separation energies are calculated for Te123 to Te130 inclusive and total decay energies are deduced for the I130–Te130 and Te123–Sb123 transitions.
THE THERMOELECTRIC POWER OF V3X COMPOUNDS
Authors: Sarachik M. P. , Smith G. E. , Wernick J. H.
Published: April 2011

The thermoelectric powers of the intermetallic compounds V3Ge, V3Si, V3Ga, and V3Sn have been measured from their superconducting transition temperatures to room temperature. It is found that the thermoelectric coefficients are all positive and about 10 μv/° K at room temperature. The coefficients for V3Si, V3Ga, and V3Sn are monotonically increasing functions of the temperature, whereas for V3Ge there is a pronounced maximum at about 60° K. The results are discussed in terms of a two-band model consisting of a conduction band and a d-band.
THE FRESNEL FIELD IN KOTTLER'S DIFFRACTION THEORY
Authors: Karczewski B.
Published: April 2011

The Kottler theory of electromagnetic diffraction has been shown to be in good agreement near the boundary of geometrical shadow with the Kirchhoff scalar approach.
Kπ SCATTERING
Authors: Margolis B. , Rotsstein A.
Published: April 2011

The s-wave Kπ phase shifts for the two isospin states T = 1/2 and T = 3/2 are calculated on the basis of a variational method due to Schiff by assuming a quartic boson–boson interaction. The trial forms for the state functions are optimized by making the expectation value of the field Hamiltonian stationary. The trial functions used are of separable form and it is hoped that with the development of more elaborate functions, this variational method may lead to a description of the Kπ resonances. In particular, the vacuum, single-particle, and two-particle (scattering and bound) states are investigated. Finally, the results are compared with the effective-range formula for Kπ scattering developed by Lee (1960).
THE UNMATCHED GUARD METHOD OF MEASURING THERMAL CONDUCTIVITY AT HIGH TEMPERATURES
Authors: Laubitz M. J.
Published: April 2011

The theory of a new, precise method of measuring thermal conductivity is described in detail. The results obtained by this method are insensitive to radial and longitudinal misalignment of the components of the apparatus, and to deviations from nominal in the calibration curves of the thermocouples. Results of some experimental checks of this method are given.
CRACK FORMATION IN ICE PLATES BY THERMAL SHOCK
Authors: Gold L. W.
Published: April 2011

Cracks were formed in the surface of smooth ice blocks by bringing them into contact with a second colder ice block. The temperature change within each block and the associated thermal stress were calculated. The ultimate strength of a smooth ice surface was found to be between 30 and 40 kg/cm2. The surface temperature shock necessary to produce this stress was about 6 °C. There was a marked preference for the cracks to form parallel to the basal and prismatic planes.Maximum depth of crack penetration was obtained with ice blocks made up of only one or two crystals with their C axis perpendicular to the surface. The minimum observed value for the strain energy release rate at crack arrest was calculated to be between 150 and 200 ergs/cm2 for each cm2 of new crack surface, indicating that for the crystallographic orientation and stress distribution of those experiments there was relatively little plastic deformation at the crack tip. The associated crack edge stress intensity factor was between 3.0 × 106 and 3.5 × 106 dynes cm−3/2. It was observed that the calculated strain energy release rate at crack arrest increased with decreasing average size of segments formed by the cracks. It is considered that the calculated strain energy release rates for these cases may exceed the true values because of reduction in the stress between the surface and the bottom of the crack prior to crack arrest.
CARTESIAN TENSOR EXPANSION OF THE FOKKER–PLANCK EQUATION
Authors: Shkarofsky I. P.
Published: April 2011

The Fokker–Planck equation is expanded via Cartesian tensors. The results, valid for arbitrary mass ratio, reduce to known expressions for the f0, (isotropic) and f1 (directional) parts of the distribution. The same analysis also gives the relation for the f2 (tensor) part of the distribution. Nonlinear and recoil terms are also investigated. The f0 relation yields relaxation times and energy equipartition times for arbitrary velocity distributions. The ion recoil term is important for low-frequency waves in the electron f1 equation but is negligible in the electron f2 equation. The electron–electron contributions to the f1 and f2 collisional terms are of the same order as the electron–ion contributions. Except for momentum transfer calculations, the ion–ion collisional terms dominate over the ion–electron terms in the ion collision equations referring to the directional (F1) and tensor (F2) parts of the ion distribution.
PHONON BROADENING OF IMPURITY SPECTRAL LINES: II. APPLICATION TO SILICON
Authors: Barrie Robert , Nishikawa Kyoji
Published: April 2011

The general theory of the phonon broadening of impurity spectral lines discussed in an earlier paper is applied to shallow impurity levels in silicon. With the use of a modified hydrogenic model and a deformation potential description of the electron–phonon interaction, expressions are obtained for typical contributions to the half-widths. Some numerical estimations are made for both acceptor and donor cases and are compared with experiment.
THE ANALYTIC STRUCTURE OF FUNCTIONS DEFINED BY MULTIPLE INTEGRALS
Authors: Cunningham John
Published: April 2011

Modes of analytic continuation of scattering amplitudes are studied. Some features of paths, connecting regions where the amplitudes are mathematically well defined to ones of physical interest, and which lie on the Landau curves, are described.
THE EFFECT OF AN ARRAY OF OBSTACLES ON HEAT CONDUCTION IN GASES
Authors: Mate C. F.
Published: April 2011

The main features of heat conduction in an obstructed gas are described with the help of a cell model of the obstacle array. An expression is derived for calculation of the average conductivity of the obstructed gas over a wide pressure range extending to indefinitely low pressures. Conductivities calculated from this expression are compared with low-temperature data for helium gas in powdered alumina. The relevant transport properties of gases are summarized in an appendix.
THE DECAY OF METASTABLE ATOMS IN A PULSED DISCHARGE IN KRYPTON
Authors: Smith D. S. , Turner R.
Published: April 2011

The rate of decay of metastable krypton atoms in the 1s5 state has been measured in the range 0.2 to 1.8 mm Hg of krypton pressure. The measured values of decay time τ can be fitted to a theoretical curve 1/τ = 30/p + 75p + 44p2∙ (p = pressure in mm). The effects of collisions with electrons have been estimated. Comparison with previous measurements of destruction frequencies in neon and argon show that the relative importance of three-body collisions is greater for krypton than for the other two gases.
NOTE ON THE VLASOV EQUATION FOR PLASMAS
Authors: Wu Ta-You , Sundaresan M. K.
Published: April 2011

The linearized Vlasov equation is solved as an initial value problem by expanding (the Fourier components of) the distribution function in a series of Hermite polynomials in the momentum, with coefficients which are functions of time. The spectrum of frequencies is given by the eigenvalues of an infinite matrix. All the frequencies ω are real, extending from small values of order ω2 = k2(u22), where (u22) is the mean square velocity of the positive ions (of mass M), to [Formula: see text], where ω1, (u12) are the plasma frequency and mean square velocity of the electrons (of mass m). The classic work of Landau solves the Vlasov equation for (the Fourier transform of) the potential for which he obtains the "damping", whereas Van Kampen and the present writers solve the equation for (the Fourier transform of) the distribution function itself. While the present work gives results equivalent to those of Van Kampen, the method is simpler and in fact elementary.
REACTIVE ENERGY IN APERTURE FIELDS AND APERTURE Q
Authors: Collin R. E. , Rothschild S.
Published: April 2011

An analysis of the properties of a radiating aperture in an infinite conducting screen is made by expanding the field in terms of plane waves. Expressions for the far zone field, power flow, and energy stored in the reactive electric and magnetic fields are obtained. This enables the Q of the aperture to be evaluated. A theorem on the frequency sensitivity of the aperture susceptance (the rate of change of susceptance with frequency is proportional to the total energy stored in the reactive field) is proved. Finally a method of optimizing the aperture field to obtain, for example, maximum gain and minimum Q is developed. The method is based on an application of the sampling theorem and reduces the optimization problem to one of optimizing a polynomial function.
OBSERVATION OF DELAYED PROTON RADIOACTIVITY
Authors: Barton R. , McPherson R. , Bell R. E. , Frisken W. R. , Link W. T. , Moore R. B.
Published: April 2011

The observation of delayed proton emission is reported. Bombardment of both aluminum and silicon with 97-Mev protons leads to the emission of delayed proton energy groups from 2 to 5 Mev. They follow the beta decay of Si25 (T1/2 about 0.3 sec) to proton-unstable excited states of Al25. Delayed protons were also observed following bombardment of Mg, Na, F, N, and O. The energy groups in the delayed proton spectra are explained by assuming that, in each case, a nuclide whose (Z, N) is of the form (2k + 2, 2k − 1) is the parent nuclide, the decay chain being of the form:[Formula: see text]The observed delayed proton energies are those deduced by assuming that known levels of the intermediate nucleus emit the protons. Agreement of this kind, together with cross bombardment, threshold, and lifetime measurements, established the observation of the previously unreported Si25. With less experimental detail, delayed protons have been assigned to the decay schemes of the previously unreported Mg21, Ne17, and O13.
PLANE WAVE SPECTRA IN GRATING THEORY: II. SCATTERING BY AN INFINITE GRATING OF IDENTICAL CYLINDERS
Authors: Millar R. F.
Published: April 2011

The scattering of a scalar plane wave by an infinite grating of identical elements is analyzed by methods of Part I. Representations for the field outside the grating, and between the elements, are given. It is shown that the discrete plane-wave spectrum for the exterior field, in general, may be continued analytically into the grating; in particular, this exterior field representation for a grating of circular cylinders is valid everywhere other than on the plane containing the axes of the cylinders. Field representations within the corrugations of a reflection grating are also discussed; it is inferred that analytic boundary data prescribed on an analytic boundary surface permit continuation of the exterior solution into the grating. An equation is derived which relates the scattering function of an element in the grating to its form for an isolated cylinder. From this relation it is shown that the many-body scattering function has branch points in the plane of complex angle of incidence at the Rayleigh wavelengths, and is two-valued in a suitable neighborhood of each branch point. Elsewhere, including the neighborhood of grazing incidence, the scattering function is analytic with respect to the angle of incidence. It is shown, for a grating of arbitrary elements, that the scattered field for grazing incidence takes an especially simple form.
DIFFUSION IN MULTICOMPONENT METALLIC SYSTEMS: VII. SOLUTIONS OF THE MULTICOMPONENT DIFFUSION EQUATIONS WITH VARIABLE COEFFICIENTS
Authors: Kirkaldy J. S. , Lane J. E. , Mason G. R.
Published: April 2011

Analytic solutions of the multicomponent diffusion equations are only available for constant diffusion coefficients, a situation which is unlikely in real systems. Using an extension of Boltzmann's treatment for binary diffusion, the multi-component diffusion equations with variable coefficients have been converted to an integral form which can be solved by iterative methods. For those multicomponent systems in which the off-diagonal Onsager L-coefficients may be approximated by zero, a simple numerical method of solution of the activity profile has been derived, which is applicable even if the D's are variable. A method is developed for designing and analyzing experimental diffusion couples to obtain the maximum amount of information about variable coefficients in ternary systems. The possibility of obtaining thermodynamic data from diffusion experiments is discussed.
STRUCTURE OF THORIUM A-LINE
Authors: Ewan G. T.
Published: April 2011

The shape of the Th A-line (L1 39.85 kev) has been studied at high resolution in the Chalk River β-ray spectrometer. The broadening of the line is found to be due to two effects: (1) the nuclear recoil due to the α decay preceding the 39.85-kev transition, and (2) the presence of the K-conversion line of a 115.1-kev transition in Bi212. The relative intensities of the K 115.1-kev line and the L1 39.85-kev line are (0.195 ± 0.02):1. The energy separation is 142 ± 8ev.
MAGNETORESISTIVITY BEHAVIOR OF SOME DILUTE Cu–Fe, Gu–Mn, AND Gu–Zn ALLOYS AT LIQUID HELIUM TEMPERATURES
Authors: Muto Y. , Noto K. , Hedgcock F. T.
Published: April 2011

Resistance measurements in magnetic fields up to 100 kilo-oersteds have been made on some Cu–Fe, Cu–Mn, and Cu–Zn alloys in the liquid helium temperature range, where the Cu alloys containing paramagnetic impurities exhibit resistance anomalies. The sign of both the transverse and longitudinal magnetoresistivity in Cu–Fe alloys at 4.2 °K is positive for alloys containing less than 0.04 at.% Fe and negative for alloys containing more than this concentration of iron. For all of the Cu–Fe alloys studied the magnitude of the magnetoresistance normalized to the zero-field resistivity is larger at 4.2 °K than at lower temperatures.The sign of both the transverse and longitudinal magnetoresistivity in a Cu – 0.007 at.% Mn alloy at 4.2 °K is positive for all magnetic field values. However, at lower temperatures (1.3°K) the same alloy has a negative magnetoresistivity at low fields, which saturates and becomes positive at higher field values. The rate of change of the normalized transverse and longitudinal magnetoresistivity for Cu–Mn is also larger at 4.2°K than at lower temperatures.The magnetoresistivity of the Cu–Zn alloys decreases with decreasing field strength and increasing Zn concentration, with a modified Kohler law fitting the experimental data. The transverse magnetoresistivity is always larger than the longitudinal one, and for the most dilute Cu–Zn alloy the magnitude of both components is of the same order as that of pure Cu.It is found possible empirically to separate the Cu–Mn magnetoresistivity data into a positive and negative component; however, for the Cu–Fe alloys studied the present analysis proves the existence of a negative component for the more concentrated alloys but does not permit a separation from the total magnetoresistivity effect.
EFFECT OF MAGNETIC FIELD NONUNIFORM ITIES ON THE PERFORMANCE OF DOUBLE-FOCUSING MASS SPECTROMETERS
Authors: Cambey L. A. , Ormrod J. H. , Barber R. C.
Published: April 2011

The effects of magnetic field nonuniformities on the focusing properties of the three types of magnetic field sectors commonly employed in mass spectrometers and spectrographs are discussed. Two types of magnetic field non-uniformities are considered: those in which the vertical component of the magnetic field, Bz, varies along the central ion path ("azimuthal nonuniformities") and those in which Bz is a function of the displacement in the direction normal to the central ion path ("radial nonuniformities"). To facilitate the interpretation of results, the ions entering the magnetic field are assumed to have the velocity dispersion required to form a velocity focus at the position of the direction focus (i.e., to give a double focus), if the magnetic field were uniform.
SPIN–PARITY COMBINATIONS OF LEVELS IN Mg24 BELOW 9.6-MEV EXCITATION
Authors: Hird B. , Kuehner J. A. , Almqvist E. , Brassard C.
Published: April 2011

Alpha-particle spectra from the reaction C12(O16, α)Mg24 have been examined at 0°, 3°, and 15° with a magnetic spectrometer at a number of bombarding energies between 22 Mev and 24 Mev. The parities of all the levels in Mg24 up to and including the 9.517-Mev level are established as (−)J with the following exceptions: 5.224 Mev, 7.746 Mev, 7.808 Mev,8.864 Mev, and 9.456 Mev, which are probably (−)J+1. Further implications of these measurements on spin and parity assignments are discussed.
ADSORPTION OF HELIUM FOUR ON SARAN CHARCOAL AT TEMPERATURES BELOW 5 °K
Authors: Dacey J. R. , Edwards M. H.
Published: April 2011

Isotherms for the adsorption of helium on Saran charcoal in the region of the boiling point of helium and for pressures above 7 × 10−4 torr have been determined and isosteric heats of adsorption calculated. The average density of the adsorbed helium is 0.249 g cm−3. It is concluded that the first two layers of helium on the carbon are in a solid state while higher layers are a liquid. The view that Saran charcoal contains a system of micropores 10–15 Å in width is confirmed.
VARIATIONS IN THE SCINTILLATION OF COSMIC RADIO SOURCES DEPENDENT ON THE SCINTILLATION RATE
Authors: Harrower G. A. , Srivastava R.
Published: April 2011

A study of scintillation of the source Cassiopeia A at 52 Mc/s, using apparatus capable of separating the scintillating wave form into various frequency components, reveals differences between faster scintillations and slower scintillations with the division occurring at approximately 25 seconds. The sidereally dependent differences are pronounced; the local solar time dependent differences are small. All scintillation activity during 1962 showed strong correlation with the number of solar flares.
MEASUREMENTS ON AN EXPERIMENTAL MODEL OF A NEW "THERMAL GRADIENT" VACUUM PUMP
Authors: Schumacher B. W. , Falckenberg H. R. , Thiede U.
Published: April 2011

An experimental model of a new type of vacuum pump was built and its behavior studied. Pumping was achieved without moving parts, fluid-driving media, or absorption media, by using thermal effects only. Results showed that pumps of practical size and performance most likely can be built.
OBSERVATIONS UPON CLEAR-AIR STRATIFICATION IN THE LOWER TROPOSPHERE
Authors: Bell M. B. , Hay D. R. , Johnston R. W.
Published: April 2011

A study of the fine structure of air refractivity in the lower troposphere has been continued through the spring and summer of 1962 by the observation of weak radio reflections from clear air (radar angels), with a vertically directed radar of special design operating at 6770 Mc/s. These observations have been limited to the layer of frictional influence, within 1500 meters of the surface. The interpretation suggests that the reflecting centers are broad strata whose refractivity contrasts weakly with that of their environment, whose vertical depths are no more than a few centimeters, and which are either flat over horizontal distances of at least several meters or concave downwards with radii of curvature somewhat less than their height above ground. The incidence of transitory reflections generally follows a regular distribution in the vertical, with a maximum at 300 meters; the form of this distribution is modified by the intrusion of weather fronts, thermals, and other clear-weather structures. The transitory reflecting stratum is cut off from its generating source early in its life history, to be dispersed into its environment by molecular or eddy diffusion. The total incidence of transitory angels fluctuates quasi-periodically in time, with a period of about 10 minutes; it is suggested that this periodicity is due to the influence of internal gravity waves in the atmosphere. In contrast, persistent reflections are associated with a more stable environment; the maximum incidence is at the lowest heights observed, with a gradual decrease towards higher levels. Their relationship to clear-weather structure is less certain than for the transitory reflections. The persistent reflecting stratum must be replenished continuously by the generating source during its lifetime to offset diffusion into the environment.
ASSESSMENT OF THE RADIATION DOSE TO CANADIANS FROM FALLOUT
Authors: Grummitt W. E. , Guthrie J. E.
Published: April 2011

Sr89, Sr90, Cs137, and plutonium in precipitation collected at Deep River, Ontario, have been measured for the 10-year period ending December 1962. The accumulated deposit, in mc/km2, amounted to 34 mc of Sr90, 53 mc of Cs137, and 0.5 mc of plutonium. The mean concentration of Sr90 in rain (and snow) for the same period was 4.2 pc/l. Using these results, the 30-year infinite plane γ-dose from fallout deposited prior to 1963 was calculated to be 27 mrem. It is shown that this calculation applies to all of southern Canada.
SCATTERING BY A PERFECTLY CONDUCTING CYLINDER IN A COMPRESSIBLE PLASMA
Authors: Seshadri S. R. , Morris I. L. , Mailloux R. J.
Published: April 2011

The scattering of a plane electromagnetic (EM) or plasma (P) wave by a perfectly conducting and rigid circular cylinder immersed in an isotropic compressible plasma is treated. Expressions for all the physical quantities of interest are obtained in the form of infinite series. For the case of a plane EM wave incidence, numerical results for the current induced on the surface of the cylinder, the total scattering cross sections, and the backscattering cross section are obtained as a function of ke0a for various values of the plasma frequency, where a is the radius of the cylinder and keo is the wave number of the EM wave in free space.
NEW 5− AND 6+ STATES IN Ne20
Authors: Kuehner J. A. , Pearson J. D.
Published: April 2011

Excited states of Ne20 at excitation energies of 8.46 Mev and 8.79 Mev have been identified and assigned spin and parity values of 5− and 6+, respectively. The excited states were produced in the C12(C12, α)Ne10 reaction and the spin assignments were made on the basis of angular correlations of the decay alpha particles from these states leaving O16 in its ground state. It is postulated that the 5− state is the fourth member of a K = 2 negative-parity rotational band based on the 2– 4.97-Mev state and that the 6+ state is the fourth member of a K = 0 rotational band based on the 0+ ground state of Ne20.
LEVELS IN Ne20 FROM THE C12(C12, α)Ne20 REACTION
Authors: Pearson J. D. , Almqvist E. , Kuehner J. A.
Published: April 2011

A high-resolution magnetic spectrometer which compensates for dE/dθ effects has been used to examine levels in Ne20 produced in the C12(C12,α) Ne20 reaction, using the C12 beam from the Chalk River tandem accelerator. Levels were observed at excitations (Mev) of 4.25, 4.97, 5.62, 5.79, 6.71, 7.02, 7.17. 7.21, 7.43, 7.85, 8.46, 8.71, 8.79, 8.87, 9.04, 9.11, (9.31), 9.48, and 10.24 all with an estimated error of ± 0.02 Mev.
THE BETA DECAY OF Cs134
Authors: Wijngaarden W. Van , Connor R. D.
Published: April 2011

Magnetic spectrometer studies have revealed that the β decay of Cs134 proceeds via three partial spectra whose end-point energies, intensities, and log10ft values are as follows:[Formula: see text]No evidence is found for β transitions of intermediate energies. Upper limits have been placed on two previously reported β transitions of higher energy as follows:[Formula: see text]These β intensities to a revised level scheme produce a good balance with the γ-ray intensities depopulating the levels.The Qβ− value is 2.059 Mev.
ELECTRICAL RESISTIVITY, HALL COEFFICIENT, AND THERMOELECTRIC POWER OF AuSb2 AND Cu2Sb
Authors: Pearson W. B.
Published: April 2011

The electrical conductivity and absolute thermoelectric power of AuSb2 and Cu2Sb have been measured between 2.5° and 300 °K. Room-temperature Hall coefficients were also determined. Iron impurity causes a giant diffusion thermoelectric power at low temperatures in the compound Cu2Sb, as it has previously been found to do in Cu, Ag, and Au.
ON THE THEORY OF SCHUMANN RESONANCES IN THE EARTH–IONOSPHERE CAVITY
Authors: Wait James R.
Published: April 2011

The concept that the concentric region between the earth and the ionosphere acts as a cavity resonator was proposed by Schumann over a decade ago. It is the purpose of this paper to review the theory of these cavity resonances. Some of the assumptions used in current work on the subject are also discussed. An alternative derivation is presented which appears to be more general than any given heretofore.
SPIN–LATTICE RELAXATION TIME OF Fe3+ ION
Authors: Madan M. P.
Published: April 2011

The spin–lattice relaxation time T1 of Fe3+ ions in iron–rubidium alum [RbAl(SO4)2∙12H2O], in rutile [TiO2], and in potassium cobalticyanide [K3CO(CN)6] has been measured in the temperature range 1.6 °K to 4.2 °K at a frequency of 9400 Mc by the pulse saturation technique. For Fe3+ in rubidium alum, it is found that for crystals having a nominal concentration of 1% and lower the variation of relaxation time with temperature is of the form [Formula: see text]; for higher concentrations the variation is of the form [Formula: see text]. Cross-relaxation effects are noticed for higher concentrations at all settings of crystal orientations. For Fe3+ in rutile on the average, the relaxation time is approximately inversely proportional to temperature, thus indicating the presence of a direct process. There is no significant change in the relaxation time, when the angle of the applied magnetic field with the crystal axis is varied. For Fe3+in K3Co(CN)6, above 2.8 °K, it is found that the relaxation time is proportional to T−8; this is consistent with a two-phonon interaction process (Raman). It is not believed that at the lowest temperature used in this experiment relaxation is taking place through a single-phonon process (direct).
SPIN–LATTICE INTERACTION EXPERIMENTS ON COLOR CENTERS IN QUARTZ
Authors: Taylor A. L. , Farnell G. W.
Published: April 2011

The paramagnetism of the color centers in smoky quartz is caused by the electron which is missing from a nonbonding oxygen orbital near an aluminum impurity. The effects produced by externally introduced microwave phonons on the spin-resonance signal from these color centers have been studied in detail as a function of the relative phonon and spin-resonance frequencies, the phonon power, the spectrometer power, the magnetic field angle, and the phonon polarization. As has been noted previously, these interactions do not conform with those observed in other paramagnetic crystals. Effects of an applied electric field on the resonance lines and various further experiments on the color centers in smoky quartz are reported; two in particular suggest that the "hole", the missing electron, makes thermally excited transitions between two different sites adjacent to a given impurity atom. One of the experiments is a measurement of the cross relaxation which takes place between the various lines of the spectrum, while the other is a measurement of the low-frequency dielectric loss found at liquid helium temperatures. An attempt is made to discuss the spin-phonon results in terms of such transitions for the holes.
THE MICROWAVE SPECTRUM OF DICHLOROFLUOROMETHANE
Authors: McLay David B.
Published: April 2011

The microwave spectra of C12HFCl235 and C12HFCl35Cl37 have been measured in the frequency range from 10 to 35 Gc/s. Enough R branch and Q branch rotational transitions have been measured in each case to determine the rotational constants A = 6988.73 ± 0.02, B = 3307.25 ± 0.05, and C = 2350.03 ± 0.02 Mc/s for CHFCl235 and A = 6943.37 ± 0.05, B = 3219.58 ± 0.04, and C = 2300.57 ± 0.06 Mc/s for CHFCl35Cl37. The out-of-plane coordinate of Cl35 in the symmetric species has been deduced to be 1.4350 ± 0.0006 Å and, if the C–Cl bond length is assumed to be 1.750 ± 0.005 Å, then the Cl–C–Cl angle can be calculated to be 112.2 ± 0.5°. The analysis of the hyperfine structure has led to the values eQVaa = −41.0 ± 0.2 Mc/s, eQVbb = +11.37 ± 0.13 Mc/s, and eQVcc = 29.62 ± 0.13 Mc/s for the diagonal components of the quadrupole coupling tensor along the principal inertial axes. The results are consistent with a cylindrically symmetrical charge distribution around the C–Cl bond and a quadrupole coupling tensor component of eQVzz = −76.75 Mc/s in the direction of the bond. The only impurity in the sample, obtained from the Matheson Company, seems to have been a trace of HCCF for which the J = 0 → 1 transition has been measured.
ON THE NECESSITY OF AXIAL ASYMMETRY IN SOME NUCLEI
Authors: Gupta S. Das , Gunye M. R.
Published: April 2011

It is pointed out that the relative positions of the second 2+ level and the first 4+ level in some nuclei suggest that they possess axially asymmetric equilibrium deformation.
SPECTROGRAM OF ARTIFICIAL AURORA NEAR SAMOA OF JULY 9, 1962, AND ASSOCIATED LITHIUM EMISSION IN TWILIGHT
Authors: Tinsley B. A.
Published: April 2011

Observations made from Western Samoa of the artificial auroral display in the region magnetically conjugate to the nuclear explosion of July 9, 1962, are described. Notable features of the display were its great intensity (6.5 × 106 rayleighs for [OI] 5577 Å), the presence of helium emissions, and characteristics of helium or heavier particle excitation. Lithium emission was found to be present in twilight for observations made up to six days after the explosion.
A SENSITIVE DILATOMETER FOR USE AT LOW TEMPERATURES
Authors: Shapiro J. M. , Taylor D. R. , Graham G. M.
Published: April 2011

A new dilatometer for the measurement of thermal expansion at very low temperatures is described. It employs a doubly twisted strip which converts the linear expansion of a specimen into a rotation which can be measured with an optical lever. The present limit of detection of the apparatus is about 3 × 10−10 cm change in length of a specimen 8 cm long. So far, measurements have been made only on copper; these indicate that below 8 °K α is given by 3.10 × 10−11T3 + 2.78 × 10−10T/° K. This implies a limiting lattice Grueneisen constant, [Formula: see text], of 1.95, and an electronic γe of 1.21.
ISOTOPE SHIFT IN BARIUM
Authors: Kelly F. M. , Tomchuk E.
Published: April 2011

Isotope shifts and magnetic hyperfine structures for lines in the first and second spectra of barium are reported and compared with previous results in an attempt to remove anomalies which have existed in isotope-shift determinations. The unusual order of the barium isotopes in the Ba I resonance line has been partially confirmed by observations on Ba II.
ANGULAR DIFFERENTIAL DOSE ALBEDO MEASUREMENTS FOR 0.66-Mev γ's INCIDENT ON CONCRETE, IRON, AND LEAD
Authors: Clifford C. E.
Published: April 2011

The angular dependence of the scattered dose produced by 0.66-Mev γ's incident on concrete, iron, and lead was measured for angles of incidence of 0°, 30°, and 60°. The angular distributions from these materials were dependent both on the angle of incidence and on the angle of scatter to a detector and could not be related to each other by simple multiplicative factors. As the angle of incidence increased, the scattering in the forward directions became increasingly anisotropic for each material. For iron exposed at normal incidence the effect of the scatterer thickness on the angular distribution of the scattered dose was measured also.A Monte Carlo program was used to study the distribution of distances between the point of incidence and the point at which a backscattered γ emerged and indicated that scatter from the "shadow" zone could be significant in some shielding studies. The program was used also to study the distribution of depths of the point at which a backscattered γ had its last scattering interaction.
THEORY OF THE Q BRANCH OF THE INFRARED SPECTRUM OF SOLID HYDROGEN
Authors: Sears V. F. , Kranendonk J. Van
Published: April 2011

The theory of the zero-phonon Q branch of the infrared spectrum of solid hydrogen is developed. At low ortho-concentrations the spectrum can be analyzed in terms of transitions due to single and pairs of neighboring ortho-molecules. The Q1(1) transitions due to single ortho-molecules give rise to a sharp absorption line, the Q2(0) transitions to a band with a total width of about 3 cm−1 and a line profile following approximately a Δν3/2 law. The integrated intensities of these lines are calculated and compared with the experimental data. The Q1(1) and Q1(0) transitions due to pairs of ortho-molecules give rise to a number of components resulting from the removal of the ninefold degeneracy of the orientational state of the pair of ortho-molecules by the quadrupole–quadrupole interaction. The intensities and frequency separations of these components are calculated. Finally, a calculation is presented of the total integrated intensity of the zero-phonon Q branch at arbitrary ortho-concentrations. These theoretical results are of importance for the study of the percolation problem in solid hydrogen, and of the order-disorder transition taking place at high ortho-concentrations.
PLANE-WAVE APPROXIMATION FOR THE SCATTERING AMPLITUDE
Authors: Chan H. H. , Razavy M.
Published: April 2011

Different methods of calculating the S-wave scattering amplitude using the plane-wave approximation are discussed. The resulting scattering amplitudes satisfy the unitarity condition and for high energies approach the Born approximation asymptotically. These methods are applied to the special class of potentials that can be expressed as an infinite sum of exponential potentials, and in particular to some potentials for which the exact solutions are known. It is found that imposing the unitarity condition on the Born approximation, in general, does not improve the result of the calculation.
THE NEAR INFRARED SPECTRUM OF THE NIGHT AIRGLOW OBSERVED FROM HIGH ALTITUDE
Authors: Gush H. P. , Buijs H. L.
Published: April 2011

The infrared emission spectrum of the upper atmosphere between 1.2 and 2.5 microns has been measured at night by means of a Michelson interferometer carried to an altitude of 90,000 feet by a balloon. The complete Δν = 2 sequence of rotation–vibration OH bands has been observed at a resolution sufficient to resolve the rotational structure. The (0, 0) band of the electronic transition [Formula: see text] of oxygen at 1.27 microns has been observed in the night-sky spectrum for the first time. Its brightness is comparable with that of the (4, 2) OH band at 1.6 microns.