bluuebunny/crossref_metadata_2025 huggingface dataset:
SMALL COSMIC-RAY INCREASES MEASURED AT GROUND LEVEL, SEPTEMBER 3, 1960, JULY 18 AND JULY 20, 1961
Authors: Wilson B. G. , Rose D. C. , Wilson Margaret D.
Published: April 2011

Three small increases in cosmic-ray intensity, observed in high counting rate neutron monitors in Canada, are described and the results examined in relation to the impact zone effect with particular reference to recent studies by McCracken. Pronounced impact zone effects were observed during the July 18, 1961, event, the largest of these three increases, while the September 3, 1960, event showed no such effects. Considerations of the state of the interplanetary magnetic fields at these times show that these results are consistent with McCracken's explanations. The sharp rise to maximum of the July 20, 1961, increase would suggest strong impact zone effects, but such conclusions that can be drawn from the limited data and the small magnitude of the increase suggest that it does not conform with the usual pattern.
ELECTRON SHOWER CURVES IN LEAD FOR ENERGIES OF 3 TO 40 Bev
Authors: Wilson Margaret D. , McDiarmid I. B.
Published: April 2011

Electron–photon showers in lead have been studied in a multiplate cloud chamber at energies up to 40 Bev. The numbers of electrons under various thicknesses of lead have been determined by a photometric method combined with scintillator measurements. Experimental shower curves for several energies are given as well as the mean number of electrons at the shower maximum as a function of shower energy. The results are compared with standard shower theory under Approximation A with an assumed low-energy cutoff.
THE ROTATIONAL ENERGY LEVELS OF DIATOMIC MOLECULES IN 4Σ ELECTRONIC STATES
Authors: Hougen Jon T.
Published: April 2011

Expressions are derived for the rotational energy levels of diatomic molecules in 4Σ states. These expressions contain two rho-type doubling parameters (γ's), and thus differ from earlier expressions which contain only one such parameter. The new expressions are in better agreement with the experimental data, though some discrepancy still exists.
SPECIFIC HEAT ANOMALIES OF Mn3AlC AND Mn3ZnC
Authors: Swanson M. L.
Published: April 2011

The specific heats of the ordered alloys Mn3AlC and Mn3ZnC were measured from −150 to 100 °C. A single higher-order anomaly was observed at the Curie temperature (−9 °C) of Mn3AlC, indicating that a ferromagnetic state existed above −150 °C. The two specific heat anomalies observed for Mn3ZnC at −35 and 65 °C showed that two co-operative magnetic transitions occurred in this alloy.
HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: XV. ROTATIONAL SPECTRUM AND MOLECULAR STRUCTURE OF CYCLOBUTANE
Authors: Lord R. C. , Stoicheff B. P.
Published: April 2011

An investigation of the rotational Raman spectra of normal and fully deuterated cyclobutane (C4H8 and C4D8) has given values of the rotational constants for these molecules. From these results it was found that the C—C bond length is 1.558 ± 0.003 Å, irrespective of whether cyclobutane belongs to the molecular point group D4h (planar C4 ring) or D2d (puckered C4 ring).
AN ANTICOINCIDENCE RING FOR A WHOLE-BODY COUNTER
Authors: McNeill K. G. , Davis L. D.
Published: April 2011

An account is given of an anticoincidence ring of plastic scintillator designed to fit round a 5 in. by 4 in. NaI crystal used as detector in a "whole-body counter". Results presented show that this system can produce a marked diminution of the background and that it can be usefully used to attenuate spectra of nuclides emitting gamma rays in cascade, thus helping in the analysis of complex spectra.
WHISTLERS AND MAGNETIC ACTIVITY
Authors: Barrington R. E. , Thompson W. E.
Published: April 2011

The relationship between whistlers and magnetic activity was studied using planetary K indices and a whistler occurrence index. This index, Wk, is the percentage of observing periods with a given Kp value during which at least one whistler was recorded. Data from eight whistler stations which were operated during the I.G.Y. were used. In almost all cases, the value of Wk was found to increase with Kp up to Kp values of 1–3, and then decrease as Kp is further increased. The decrease of Wk with increasing Kp is shown to be due in part to masking of whistlers by very low-frequency emissions, but this does not account for the whole effect. No diurnal variations of the relationship of Wk to Kp was detected, but a small seasonal change was observed. The formation and destruction of ducts or columns of enhanced ionization in the outer ionosphere are suggested as possible mechanisms for explaining some of the observed effects.
RANDOM DIGIT GENERATION WITH A NOISE SOURCE AND COUNTER
Authors: Steele K. A.
Published: April 2011

A method of generating random decimal digits with commercially available equipment is described and the effect of operating parameters on the randomness of the digits is discussed. A figure of merit is obtained for the generated sequence which is based on the relative entropies of the actual source and a hypothetical ideal source.
THE FORMATION OF STRIATION-TYPE SUBSTRUCTURE IN ALUMINUM
Authors: McGrath J. T. , Craig G. B.
Published: April 2011

Striations are one type of substructure which can form in metals as they solidify from the melt. The formation of striations is dependent upon the rate of crystal growth, the purity, and the crystallographic orientation. In aluminum single crystals, it was found that striation boundaries tended to approach a preferred (100) growth direction with increasing rate of growth and with increasing solute concentration. With different types of solute, it appears that similar values of the average concentration of solute in the liquid at the solid–liquid interface (C0/k) produced the same effect on striation direction.The number of striations found in any sample appeared to be a complex function of the purity, the orientation, and the rate of growth.
A PRECISION OXYGEN POINT CALIBRATION BATH
Authors: Berry R. J.
Published: April 2011

The usual form of oxygen point calibration bath has been modified in a simple manner to give better than an order of magnitude greater temperature stability. Tests have demonstrated that the bath can be used to transfer oxygen point calibrations from one platinum resistance thermometer to another with a reproducibility of 10−4 °C average deviation. A method for simplifying the calculation of the oxygen point resistance and a method for removing the troublesome nitrogen impurity from industrial liquid oxygen are also given. It is suggested that any laboratory can readily equip itself with a high precision oxygen point calibration bath by using a calibrated resistance thermometer in conjunction with the bath described here.
RYDBERG ABSORPTION SERIES OF CO2 CONVERGING TO THE 2Πu STATE OF
Authors: Tanaka Y. , Ogawa M.
Published: April 2011

The absorption spectrum of CO2 has been reinvestigated in the region 670–790 Å with a 6.8-meter grazing-incidence-type vacuum spectrograph. The Henning Rydberg series has been remeasured accurately along with its ν′ = 1 vibration series. In this manner, the ionization energy of the 2σu electron was determined to be 18.076 ev. Sixteen other Rydberg series were observed in this region. It was concluded that they are formed by the excitation of the 1πu electron. The ionization potentials corresponding to the energies of the 2Πu,3/2 and 2Πu,1/2 states of [Formula: see text] were found to be 17.312 ev and 17.323 ev respectively.
THE MAGNETIC MOMENT OF INDIUM-115m
Authors: Cameron J. A. , King H. J. , Eastwood H. K. , Summers-Gill R. G.
Published: April 2011

The hyperfine structure of the 4.5-hour metastable state of indium-115 has been studied by the method of atomic beam magnetic resonance. The values found for the hyperfine interaction constants are −903.5 ± 1.1 and −95.973 ± 0.010 Mc/sec in the 2P1/2 and 2P3/2 electronic states respectively. Neglecting a possible hyperfine anomaly, these correspond to a nuclear magnetic moment for In115m of −0.24371 ± 0.00005 nuclear magnetons. The construction of the atomic beam apparatus, recently completed at McMaster University, is also described.
STRUCTURE IN THE MASS–YIELD DISTRIBUTION FOR U235 FISSION
Authors: Farrar H. , Tomlinson R. H.
Published: April 2011

Recent measurements of the cumulative yields of essentially all the mass chains in the thermal neutron fission of U235 have enabled a detailed examination of the fine structure in the mass–yield curve. It has been found that most of the structure results from a slowly changing neutron yield as a function of the mass of the primary fission fragments.
SHORT-LIVED ISOMERIC STATES OF POLONIUM
Authors: Hargrove C. K. , Martin W. M.
Published: April 2011

Two new nuclear isomeric states have been discovered in Po207 by the reaction Bi209(p,3n)Po207m, and additional information has been found on a previously discovered isomer in Po205 produced by the reaction Bi209(p,5n)Po205m. A 47-μsec activity was found in Po207 which was assigned as the decay of a 13/2+ level by 310-kev M2 radiation to a 9/2− level, followed by an 820-kev E2 -γ-ray to the 5/2− ground state. The 13/2+ level in this nucleus was found to be fed by a 2.8-sec isomeric state which was assigned to the decay of a 19/2− level by 260-kev E3 radiation. A new 160-kev γ-ray was discovered in the Po205 isomer. This isomerism is caused by a 13/2+ state which decays by a 160-kev M2, 707-kev E2 cascade to the 5/2− ground state through a 9/2− level. The various multipolarity assignments are supported by measurements of intensities, lifetimes, and K conversion coefficients. The levels found are compared with similar levels in analogous nuclides of lead.
FLUORESCENCE DECAY TIME MEASUREMENTS OF ORGANIC SCINTILLATORS
Authors: Falk W. R. , Katz L.
Published: April 2011

The time dependence of the fluorescence emission from scintillators has been measured for a number of commonly used organic scintillators under alphaparticle and gamma-ray excitation. A sampling oscilloscope was used to record the pulses obtained from a fast scintillation counter. Using such a system, a gating arrangement can be employed which permits selection of only those scintillation events which deliver a predetermined total charge output from the photomultiplier. Noise within the sampling unit limits the measurements to the main fast components in the fluorescence emission. All of the plastic scintillators exhibit decay times between 2.1 and 4.4 nsec. Stilbene exhibits "particle type" discriminating characteristics with a strong second component in the decay (~35 nsec) appearing under alpha-particle excitation. In addition to the main component in the decay of anthracene, evidence of two shorter components was also found. For all the scintillators tested, the alpha-particle induced scintillation had a slightly longer decay time than the corresponding gamma-ray induced scintillation.
SOME MATRIX CALCULATIONS ON THE ISING MODEL
Authors: Robinson R. O.
Published: April 2011

The derivation of thermodynamic and magnetic properties of a crystal, on the basis of the Ising model, concerns essentially two non-commuting matrices which are here called A and B. In particular, one must evaluate the traces of Am, Bm, AmBm, and (AB)m for general integer m. The first two traces relate to the one-dimensional case; the third and fourth to the two-dimensional case. A and B are of dimension 2n, m and n being respectively the numbers of rows and columns.Previous methods of evaluating these traces have been elaborate, involving concepts such as spinor rotations in a space of 2n dimensions. In this paper elementary methods are used to derive closed expressions for the first three and the fourth is evaluated in an interesting special case.To date the Ising model has been treated exactly in two cases only. For this reason the search for simple calculational methods is of particular importance.
A NOTE ON THE CLASSIFICATION OF GEOMAGNETIC SIGNALS BELOW 30 CYCLES PER SECOND
Authors: Lokken J. E. , Shand J. A. , Wright C. S.
Published: April 2011

Simultaneous measurements in the frequency range 0.003 to 30 c.p.s. at a number of widely spaced stations have led to the identification of two general micropulsation classes, impulsive and regular, as well as to an adjacent but independent extremely low frequency (e.l.f.) background. The signal bandwidths and the dependence on geomagnetic latitude and longitude serve to distinguish the classes.
CUMULATIVE YIELDS OF LIGHT FRAGMENTS IN U235 THERMAL NEUTRON FISSION
Authors: Farrar H. , Fickel H. R. , Tomlinson R. H.
Published: April 2011

A mass spectrometric study of the relative yields of the strontium, yttrium, zirconium, and molybdenum isotopes formed in the thermal neutron fission of U235 has made possible a detailed examination of structure of the light mass region of the mass–yield curve. The relative yields of this work have been normalized to 5.77% for Sr90, and when literature and extrapolated values are taken for the remaining chains, the fission yields total 100.8%.
WAKE METAMORPHISM BEHIND A SPHERE
Authors: Magarvey R. H. , Blackford B. L.
Published: April 2011

The formation of a vortex ring on the immediate downstream side of an accelerating liquid sphere has been examined. The manner in which vorticity is transferred to the axisymmetric ring has been deduced from photographs of the sheet as it curls inward. Measurements of the distance moved by the open end of the sheet relative to the displacement of the sphere indicate the sheet length to be about 20% of the distance travelled by the sphere. The ratio of the distances gives the relative velocity of the sphere and the sheet. The former is relative to the quiescent ambient fluid and the latter to the sphere. A sequence of photographs is shown, indicating changes in the wake configuration from the beginning of motion to the ejection of the initial-vortex element.
THE HYDROGEN COMPONENT IN THE PRIMARY COSMIC RADIATION
Authors: Aly H. H.
Published: April 2011

Two values for the flux of the hydrogen component in the primary cosmic radiation have been measured. The first one was over Guam in the Marianas Islands, geomagnetic latitude λ = 0°. The value of the flux was found to be (123 ± 12) hydrogen nuclei/m2 sterad sec. The second measurement was made over Texas, λ = 41 °N., and the value found was (530 ± 53) hydrogen nuclei/m2 sterad sec. The detectors in both cases were stacks of nuclear emulsion exposed at high altitude. The results obtained in this experiment are in good agreement with the values obtained by the other authors using electronic counters flown at the same geomagnetic latitudes.
DRIFT VELOCITY OF HOT ELECTRONS IN n-TYPE GERMANIUM
Authors: Barrie Robert , Burgess R. R.
Published: April 2011

The drift velocity of electrons in n-type germanium has been measured as a function of applied electric field at lattice temperatures of 77° K and 295° K. Three directions of applied field were used, viz. (100), (110), and (111) crystal directions. The range of field strength was from 500 v/cm to 75 kv/cm. A longitudinal anisotropy was observed at 77° K but not at 295° K. All specimens showed saturation of the drift velocity at high fields. At 77° K, all (100) specimens exhibited a breakdown effect, the cause of which is not known. The results are analyzed on the basis of an extension of Stratton's theory to the case of a many-valley semiconductor.
ON THE POSSIBILITY OF INTRINSIC LOSS OCCURRING AT THE EDGES OF FERRITES
Authors: Hurd R. A.
Published: April 2011

It is shown that Maxwell's equations together with some commonly used approximations to the magnetodynamics equation of a ferrite imply that a peculiar form of electromagnetic loss may occur at ferrite–air–metal junctions. This loss, which is called "intrinsic", is non-zero even when the media involved are formally non-lossy. It is shown that an unusual loss in the problem of input to a ferrite-loaded waveguide is an intrinsic loss. Intrinsic loss is put forward as a means of resolving the thermodynamic paradox of Button and Lax.
UNE REPRÉSENTATION DE LA DIFFRACTION INSTRUMENTALE
Authors: Lansraux Guy
Published: April 2011

not available
DIFFRACTION ITÉRÉE DE LA FIGURE (sin X/X) PAR UN RÉSEAU INFINI
Authors: Lansraux Guy , Delisle Claude
Published: April 2011

not available
A MODIFIED CONTINUOUS-HEATING CALORIMETER FOR THE TEMPERATURE RANGE 15° TO 300° K
Authors: Martin Douglas L.
Published: April 2011

The calorimeter described by Martin in 1960 has been modified to permit the use of a platinum resistance thermometer and to enable measurements to be made on granular or powdered samples. Measurements in the room temperature region on the Calorimetry Conference Standard Sample of aluminum oxide show this new apparatus to have an accuracy of the order of 0.1%. Annealed and cold-worked copper samples measured previously have been remeasured from 15° to 90° K and in the room temperature region. A previously measured lithium sample has been remeasured between 100° and 300° K. Excellent agreement between the earlier and present sets of results confirms the accuracy of much previous work from this laboratory. The comparative usefulness of copper and platinum resistance thermometers in calorimetry is discussed.
ON THE EDDY TRANSFER OF WATER VAPOR ABOVE AN OUTDOOR SURFACE
Authors: Hay D. R. , Pemberton E. V.
Published: April 2011

Fluctuations in the refractive index of the air above an outdoor surface have been examined by a 180-ft microwave interferometer. The observed standard deviations of refractivity are less than 10−6. These deviations are associated with instability of the air at the interferometer path but not with instability of the air immediately above it. Smallest refractivity deviations occur for weak eddy transfer of water vapor downwards through moist air in the radio path; intermediate deviations are associated with strong eddy transfer of vapor upwards through drier air in the path. Largest refractivity deviations are observed for less vigorous upward transfer of water vapor from the surface. It is suggested that the more vigorous eddies disperse the entrained water vapor more rapidly into smaller eddies than do the less vigorous eddies; and hence, lesser local fluctuations in air refractivity appear along an extended path that is highly-unstable than along the same path under conditions of greater stability.
FRAMING CAMERA STUDIES OF THE Z-PINCH IN NITROGEN
Authors: Curzon F. L. , Churchill R. J.
Published: April 2011

The Z-pinch discharge in nitrogen has been studied by means of a high-speed framing camera. Pressure dependence of pre-pinch striations and electrode effects is reported. Development of Rayleigh–Taylor instabilities after the first pinch is verified, and the dispersion relationship is evaluated for the fastest growing m = 0 mode at a pressure of 100 μ Hg.
THE ABSORPTION SPECTRUM OF DBr IN THE VACUUM ULTRAVIOLET REGION
Authors: Stamper J. G.
Published: April 2011

The absorption spectrum of DBr has been photographed under high dispersion in the vacuum ultraviolet region. More than 30 bands have been observed and rotational analyses have been obtained for most of them. As is the case for HBr, little regularity is to be found among the various bands and the relationship between the spectra of the two isotopic species is frequently unclear. It has therefore not proved possible to arrive at any detailed conclusions as to the nature of the upper states of the bands.
PLASTIC DEFORMATION OF THICK-WALLED SNOW-ICE CYLINDERS UNDER HYDROSTATIC PRESSURE
Authors: Jellinek H. H. G.
Published: April 2011

The results of experiments on the plastic deformation of hollow snow-ice cylinders, closed at one end, as a function of circumferential stress and temperature are discussed. Data are graphed on deformation as a function of time for a snow-ice cylinder under 7.03 and 14.06 kg/cm2 hydrostatic pressure at −4.5 °C, deformation as a function of hydrostatic pressure from 2.11 to 7.03 kg/cm2, and deformation as a function of temperature at a constant pressure of 10.55 kg/cm2. The natural strain rate of closure at constant circumferential stress and temperature was a constant, which varied with circumferential stress as a sine function and was "exponentially dependent on temperature, with an activation energy of 14.1 kcal/mole at an average circumferential stress of 3.1 kg/cm2. The experiments agree well with an earlier interpretation of the plastic flow process representing flow between grain boundaries.
ON THE PROPAGATION OF E.L.F. PULSES IN THE EARTH–IONOSPHERE WAVE GUIDE
Authors: Wait James R.
Published: April 2011

The paper is concerned with the connection between frequency domain and time domain for propagation in the earth–ionosphere wave guide. Attention is focussed on the extremely low frequency (e.l.f.) range. It is assumed that the propagation constant is proportional to (frequency)v where v is a fraction between 0 and 1. For such a frequency law, the corresponding transient responses are computed. These illustrate a number of important points. In particular, it is indicated that the frequency dependence of the propagation constant could be estimated directly from the wave forms themselves without resorting to conventional spectral analysis.
OBSERVATIONS OF TWILIGHT AND SUNLIT AURORA
Authors: Lytle E. A. , Hunten D. M.
Published: April 2011

The 3914-Å band of [Formula: see text] has been observed in the zenith at twilight by a photoelectric spectrometer; simultaneous measurements of the 5577-Å line were made as a check on auroral activity. A small twilight enhancement was probably observed in the absence of aurora in 1960, but it could not be detected in 1961. After subtraction of this background, the auroral measurements showed [Formula: see text] densities of about 1000 ions/cm3 at 160 km, with a sharp decrease at lower altitudes; some displays, presumably located near 100 km, showed no twilight effect at all. It is suggested that [Formula: see text] ions are rapidly removed in the 100-km region by either charge–exchange or ion–atom interchange reactions which convert them into NO+ or some other ion. The ions in the twilight airglow are therefore probably located at 550 to 620 km, being produced there by solar extreme ultraviolet. However, this process requires a much higher N2 concentration at such heights than is normally supposed. This may be produced at times of high solar activity, and especially during magnetic storms.
NOTE ON THE PRODUCT OF RANDOM VARIABLES
Authors: Webb E. L. R.
Published: April 2011

The probability distribution of the product of independent random variables is computed for some particular cases which illustrate the principle that random variables having finite probability density at the origin give rise to products having infinite probability density at the origin.
STUDIES OF AURORAL HYDROGEN EMISSIONS IN WEST-CENTRAL CANADA: I. TIME AND GEOGRAPHICAL VARIATIONS
Authors: Montbriand L. E. , Jones A. Vallance
Published: April 2011

An account is given of some relations, between the appearance of the hydrogen lines and the other features of auroral spectra found, from the study of I.G.Y. patrol spectra and from high time resolution spectra obtained during the winter of 1959–1960. At Saskatoon it was found that quiet, weak auroral arcs characterized by strong hydrogen emission occur in the evening at the southern fringe of auroral activity while brighter forms with weak hydrogen emissions occurred simultaneously to the north. The north–south–north progression of the hydrogen emissions found by Rees, Belon, and Romick in Alaska was observed from Saskatoon. The observations show that there is a wide zone of hydrogen emission which is always present and which becomes brighter and is displaced to the south during periods of magnetic disturbance. Quiet arcs showing relatively strong hydrogen emission are characteristic, in the evening, of the southern edge of this zone.
THE INITIAL LATTICE DISTORTIONS OF MANGANESE IN COPPER, SILVER, AND GOLD
Authors: Calvert L. D. , Henry W. G.
Published: April 2011

The initial lattice distortions for manganese dissolved in copper, silver, and gold are found to be 0.383 ± 0.003, −0.003 ± 0.002, and −0.070 ± 0.002 kX per mole respectively. The precautions taken in making the lattice parameter measurements are briefly described. A similarity in the behavior of zinc and manganese as solutes in the noble metals is pointed out.
TEMPERATURE DEPENDENCE OF ABSORPTION LINE WIDTH IN BORON-DOPED SILICON
Authors: Colbow Konrad , Bichard J. W. , Giles J. C.
Published: April 2011

In boron-doped silicon, optical absorption takes place through the excitation of bound holes from the ground to excited states. This leads to a line spectrum. Due to a lack of sufficient resolution and a failure to make proper allowance for line distortion by the finite spectrometer slit width, previous authors gave incorrect values for both the low temperature half-width and the temperature dependence of this half-width. In re-evaluating these quantities, two of three previously known lines were found to be doublets. It is found that presently available theory does not explain the results adequately.
CALCULATION OF THE STRUCTURE OF THE S1(0) AND S1(0)+S1(0) LINES IN THE INFRARED SPECTRUM OF SOLID HYDROGEN
Authors: Gush H. P. , Kranendonk J. Van
Published: April 2011

At low ortho concentrations, the satellites appearing in the S1(0) infrared absorption feature of solid hydrogen arise from transitions in para molecules possessing one nearest-neighboring ortho molecule. The 15-fold degeneracy of the combination of the v = 1, J = 2 excited state of the para molecule and the v = 0, J = 1 ground state of the ortho molecule is partially lifted by the quadrupole–quadrupole interaction between the two molecules. The calculated structure of the S1(0) line is in good over-all agreement with the observed profile. The agreement is improved by taking into account the quadrupole–hexadecapole interaction. The best fit is obtained for a positive value of the hexadecapole moment of about 1.2 atomic units. The fine structure of the S1(0)+S1(0) line in the overtone region of pure parahydrogen, resulting from the splitting of the 25-fold degeneracy of the upper state by the combined quadrupole–quadrupole and quadrupole–hexadecapole interaction, is also calculated. The splitting and relative intensity of the two components of the resulting doublet structure are in close agreement with the experimental values. All the calculations are performed assuming a rigid close-packed hexagonal lattice structure. The discrepancy of about 20% between the theoretical values of the quadrupole moment of a hydrogen molecule in the v = 0 and v = 1 states and the empirical values deduced from the analysis of the S1(0) and S1(0)+S1(0) lines may be due to the neglect of the splittings arising from the coupling between the rotational motions of the molecules and the lattice vibrations.
KINETIC EQUATION OF A PLASMA IN WEAK STATIC ELECTRIC AND MAGNETIC FIELDS
Authors: Sundaresan M. K. , Wu Ta-You
Published: April 2011

The present work is concerned with the formulation of the kinetic equation for an ionized gas in a weak static electric field and magnetic induction, along the line of the theory of Bogoliubov for a neutral gas. It is an extension of the recent work of Wu and Rosenberg on the kinetic equation describing the irreversible processes in a spatially inhomogeneous ionized gas. The equation obtained describes the approach of a plasma in a weak static electric field E and magnetic induction B towards spatial homogeneity, and determines the critical field E, for a given (small) inhomogeneity, beyond which the plasma will further digress from spatial homogeneity. For the magnetic induction B, there is no critical value.
KINETIC EQUATION OF A PLASMA IN A STRONG STATIC MAGNETIC FIELD
Authors: Sundaresan M. K. , Wu Ta-You
Published: April 2011

In an extension of the recent works on the kinetic equation of a plasma in (1) the spatially homogeneous case by Guernsey, (2) the spatially inhomogeneous case by Wu and Rosenberg, and (3) the presence of "weak" static electric and magnetic fields by Sundaresan and Wu, the present work deals with the formulation of the kinetic equation of a plasma in a "strong" static magnetic field B, on the basis of the "initial condition" of Bogoliubov that introduces the time arrow, or irreversibility, into the theory. By a "strong" field, it is meant that the cyclotron frequencies of the charged particles ωσ = zσeB/mc are large compared with the "collision" frequencies, so that the randomizing effect of the interparticle interactions can be regarded as a "perturbation" on the dynamical motion of the particles. For the spatially homogeneous plasma, the kinetic equation is formulated in an expansion in powers of (1/ωσ) [Formula: see text] (1/B). For the spatially inhomogeneous case, the kinetic equation is given in a further expansion in powers of the wave vector κ measuring the spatial variation of the inhomogeneity. The theory gives the formal scheme in which the distribution functions F1(r, p, σ, t) of particles of charge zσe can be obtained to various orders in1/B and κ.
THE MAGNETIC FIELD AT THE SURFACE OF A STRATIFIED FLAT CONDUCTOR IN THE FIELD OF PLANE WAVES WITH APPLICATION TO GEOPHYSICS
Authors: Dosso H. W.
Published: April 2011

The problem of plane electromagnetic waves incident on a stratified flat conductor is considered. Expressions for the amplitude and phase of the components of the resultant magnetic field at the surface of the conductor are obtained and evaluated for a wide range of frequencies, conductivities, surface layer depths, and angles of incidence. The frequencies f = 10−3 to 103 cycles/sec and the conductivities σ = 10−11 to 10−16 emu considered are of interest in studying geomagnetic variations.
SIMPLER FORMULAE FOR THE THERMAL DIFFUSION FACTOR OF BINARY GAS MIXTURES
Authors: Saxena S. C. , Dave S. M. , Pardeshi P. A.
Published: April 2011

Simpler formulae for the second approximation to the thermal diffusion factor of a binary gas mixture are derived according to both the approximation procedures of Chapman and Cowling, and Kihara. These formulae are much simpler than the rigorous theoretical formulae from the view point of computational labor. These new formulae are derived by expanding the rigorous expressions in powers of the molecular weight ratio, M, and deleting all those terms which contain explicitly the power of M higher than two. The accuracies of these simpler formulae are demonstrated by numerical calculations on gas systems as a function of both temperature as well as composition.
TIME-OF-FLIGHT FISSION STUDIES ON U233, U235 AND Pu239
Authors: Milton J. C. D. , Fraser J. S.
Published: April 2011

The prompt mass and kinetic energy distributions resulting from the thermal neutron fission of U233, U235, and Pu239 have been reinvestigated using time-of-flight methods to measure simultaneously the velocities of the fragment pairs. A new feature shown by the present work is the existence of fine structure in the prompt mass yields. This fine structure is most pronounced at high total kinetic energies where the fragments have little excitation energy and may be associated with irregularities in the energy release as a function of mass. The fine structure is most noticeable in U235 and least in Pu239; the fragments of U235 have the lowest average excitation and those of Pu239, the highest. Another feature, which is confirmed by this work, is the large drop in total kinetic energy when the fragments are near symmetry. This decrease is about 35 Mev and is consistent either with a picture in which the nucleus with 50 protons is especially preferred or with one in which fragments at symmetric fission have an abnormally high excitation energy and a consequent large number of neutrons. The mean kinetic energies for thermal neutron fission of U233, U235, and Pu239 were found to be 167.6, 168.3, and 175.0 Mev with an error of ± 1.7 Mev.
PHOTOCONDUCTIVITY IN CUPROUS OXIDE SINGLE CRYSTALS
Authors: Fortin Emery , Weichman Frank L.
Published: April 2011

Measurements were made on both single and multicrystalline samples of Cu2O of high resistivity. Conductivity measurements gave three activation energies, 1.0, 0.5, and 0.027 ev, for different temperature regions. The photoconductivity at constant temperatures as a function of wavelength as well as the photoconductivity as a function of temperature at constant wavelengths were measured. Over the temperature range investigated no significant difference was found between single and multicrystalline material. Surface recombination states are postulated to explain the very small temperature dependence at low temperatures.
NEUTRON FLUX DISTRIBUTIONS IN CYLINDERS BY A VARIATIONAL METHOD
Authors: McKay C. D.
Published: April 2011

A variational method in which the trial functions are linear combinations of a finite set of simple basic functions is considered as a means of obtaining simple and sufficiently accurate approximations to the flux distributions in homogeneous circular cylinders which range from purely capturing to purely scattering. In particular, analytic formulae and some numerical results are given for basic functions which are even powers of the distance from the cylinder axis and some formulae are given for trial functions composed of square-pulse functions.It is found that even though the trial function with the parameters determined by the variational principle is not itself a particularly good approximation to the exact flux distribution, it may often be easily iterated in the integral equation to give a satisfactory approximation. The trial function may also be used to evaluate integrals of the flux times arbitrary weighting functions with results equivalent to those given by complex variational methods which require the introduction of an auxiliary equation.
A CALCULATION OF THE ENERGY LEVELS OF THE FIRST ROTATIONAL BAND OF Ne20
Authors: Talman James D.
Published: April 2011

The energies of the levels in the first rotational band of Ne20 have been calculated using a model which combines the shell-model aspect of the problem with the rotational nature of the observed spectrum. The agreement of the results with the experimental observations is quite good.
LOOP EXCITATION OF TRAVELLING WAVES
Authors: Senior T. B. A.
Published: April 2011

When a long, thin body is viewed at or near nose-on, a major contribution to the back-scattered field is provided by the travelling waves on the surface. To determine the role of the shadow boundary in the excitation of these waves, the more simple problem of an infinitely long circular cylinder in the presence of a ring source is considered. So that the cylinder may support a travelling wave, the surface impedance is assumed nonzero, and its magnitude is taken to be comparable with that of a typical metal at high frequencies. From the expression for the scattered field, the power going into the travelling wave, as opposed to the radiated field, is obtained. It is concluded that as a source of such waves the "launching efficiency" of a ring current is extremely small.
ENERGY LOSS IN CONDENSED MATTER OF H1 AND He4 IN THE ENERGY RANGE 4 < E < 30 kev
Authors: Wijngaarden Arie Van , Duckworth Henry E.
Published: April 2011

Measurements are reported of the energy loss suffered by H1 and He4 particles, of 4- to 30-kev energy, in passing through thin films of carbon, aluminum oxide, and VYNS. Only those particles that emerged in the forward direction were studied. Evidence is presented for identifying the stopping cross sections per atom observed in this way with Se, the electronic component of the total stopping cross section per atom. It appears that the calculated energy dependence of [Formula: see text] is somewhat in error, and that the magnitudes of the Se's for He4 are systematically too small by 10–15%.
ON THE THEORY OF RADIATIVE CAPTURE OF 1S ORBITAL ELECTRONS
Authors: Paquette Guy
Published: April 2011

A nonrelativistic calculation of the continuous gamma spectrum accompanying the capture of 1S orbital electrons in A37 is presented. The calculation takes into account the retardation effects in treating the electromagnetic interaction. A comparison with the relativistic calculation of Martin and Glauber (1958) shows that relativistic effects and screening corrections do not affect the high-energy part of the gamma spectrum. On the other hand, the retardation effects are important over the whole spectrum, except at the very lowest photon energies. The method employed in the calculation allows one to ascertain the relative importance of various intermediate states in their contribution to the spectrum intensity.
WIDTHS OF HCl OVERTONE LINES AT VARIOUS TEMPERATURES
Authors: Goldring Hanna , Benesch William
Published: April 2011

In an effort to elucidate the roles of the various factors contributing to the self-broadening of molecular lines, width measurements have been made on the overtone band of HCl at several temperatures from 200° K (dry ice) up to 1283° K. The first 10 lines of the R-branch were chosen for study and the recorded data were subjected to treatment by the equivalent width method and by direct analysis of the transmission curve widths, peaks, and slopes.The general pressure broadening theory of Anderson as amplified by Tsao and Curnutte is readily adaptable to the conditions of the present investigation. Calculations based thereon and incorporating the resonant dipole interaction in combination with a non-resonant term which maintains a ("billiard ball") lower limit to the collision cross section at an intermolecular distance, r0, yield widths which generally agree well with the experimental data. The values of the billiard ball cross section ultimately chosen to give an adequate fit were r0 = 6.2, 6.0, 5.7, and 5.5 A corresponding to the temperatures 200, 300, 513, and 1283° K.
ULTRAHIGH VACUUM IN SMALL GLASS SYSTEMS
Authors: Redhead P. A. , Kornelsen E. V. , Hobson J. P.
Published: April 2011

Techniques and apparatus used in these laboratories for the production of ultrahigh vacuum in glass systems of 1 to 5 liters volume are described. Constructional details of the gauges, ionization pumps, and control circuits are given. No diffusion pumps are used with this method, thus avoiding contamination from pump fluids and the need for refrigerated vapor traps. Pressures in the range 5 × 10−11 to 10−10 torr are routinely obtained in Pyrex glass systems by minimizing the outgassing rate of the components and by pumping with small ionization pumps.
ON LARGE NONUNIFORMLY SPACED ARRAYS
Authors: Yen J. L. , Chow Y. L.
Published: April 2011

An integral approximation of the space factor of a nonuniformly spaced linear array is derived from a geometrical representation of the summation involved. At a given direction, the array is divided into stationary phase zones and destructive interference zones. The integral representation of the space factor is then evaluated approximately for the two zone types. The major characteristics of nonuniform spacing and the method of pattern evaluation are illustrated by means of two examples.
THEORY OF THE IMPACT BROADENING OF RAMAN LINES DUE TO ANISOTROPIC INTERMOLECULAR FORCES
Authors: Fiutak J. , Kranendonk J. Van
Published: April 2011

The impact theory of Raman line broadening developed previously is applied to the broadening due to anisotropic intermolecular forces. The concept of frequency degeneracy is introduced, and its importance for the broadening of isotropic Raman lines is discussed. The components of a pure vibrational Raman band show a broadening due to the anisotropic intermolecular forces proportional to the density as long as the separation between the components is large compared with the line width. However, if the components of the vibrational band are not resolved the anisotropic forces give no further broadening with increasing density. Explicit expressions are derived for the elastic and inelastic parts of the optical cross section by expanding the collision operator in powers of the interaction responsible for the broadening and retaining only the lowest-order nonvanishing terms, but preserving the unitarity of the collision operator. The dependence of the cross section on the interaction and on the molecular diameter is shown to be quite different for weak and strong interactions.
WAVE PROPAGATION IN A CYLINDRICAL WAVE GUIDE CONTAINING INHOMOGENEOUS PLASMA INVOLVING A TURNING POINT
Authors: Samaddar S. N.
Published: April 2011

Propagation of axially symmetric E-type and H-type modes of electromagnetic waves in a radially inhomogeneous plasma inside a wave guide is considered. For E-type modes conditions for the propagation of slow surface waves along the plasma–dielectric interface have been obtained. Approximate expressions for fields for wavelengths much smaller than the ratio of the gradient of the permittivity to the permittivity of the plasma are also given.It is also shown that if the dielectric constant ε(r) of the plasma vanishes along a particular surface r = r0, the electromagnetic fields for E-type modes behave singularly along this surface. In particular, if ε(r) has a simple zero at r0 ≠ 0, the radial and the longitudinal electric fields become singular as 1/ε(r0) and log ε(r0) respectively at r0. On the other hand, if ε(r) has a multiple zero at r0, the singularities of the above-mentioned fields will be as strong as a multiple pole at r0.Turning-point phenomena are also observed when the radial wave number [Formula: see text] vanishes along a surface. It is shown that the fields are oscillatory in the region [Formula: see text] and evanescent in the region [Formula: see text] for both E-type and H-type modes. The treatment of the singular behavior of the fields at ε(r) = 0, and of the turning-point phenomena at [Formula: see text], does not consider any boundary effect; therefore the results obtained here will be valid also for an inhomogeneous plasma column in free space.
THE STATIC POTENTIAL ATTAINED BY AN INFINITE CYLINDER IMMERSED IN A MOVING AND LOW DENSITY PLASMA OF INFINITE EXTENT
Authors: Sengupta Dipak L.
Published: April 2011

The static potential acquired by an infinite cylinder immersed in a low density collisionless plasma is discussed in detail. It is assumed that the plasma is uniform at large distances from the cylinder and of infinite extent and has a constant drift velocity in one specific direction. Approximate expressions for the distribution functions of the electrons and ions in the presence of the conducting cylinder are derived from the collisionless Boltzmann equation. Expression for the static potential of the cylinder is derived from the condition that the electrical neutrality of the plasma is maintained at large distances from the cylinder. Simplified expressions for the static potential are given for various physical situations. The case of stationary plasma is obtained as a special case of the former when the drift velocity equals zero. Numerical values are given for some cases.
SCATTERING FROM A CYLINDER COATED WITH AN INHOMOGENEOUS DIELECTRIC SHEATH
Authors: Yeh C. , Kaprielian Z. A.
Published: April 2011

As a space vehicle re-enters the atmosphere, a plasma sheath, surrounding the vehicle, is generated. It is well known that the sheath is inhomogeneous. However, to make this problem suitable for theoretical analysis, most investigators make the assumption that the sheath is homogeneous. To investigate the validity of this assumption, the idealized problem of the scattering of plane waves by a conducting cylinder coated with a stratified dielectric sheath is considered. The wave equation is separated using the vector wave-function method of Hansen and Stratton. It is then applied to the plane-wave scattering problem. The backscattering cross section is defined and obtained. Analytical expressions for the scattering coefficients of a thin inhomogeneous sheath are also given. Numerical computations are carried out for a specific variation of the dielectric sheath: i.e., ε(r) = ε0α/k0r, where α is a constant, k02 = ε2 με0, and ε0 is the free-space dielectric constant. Results are compared with the homogeneous sheath problem; the dielectric constant of the homogeneous sheath is taken to be the average value of that for the inhomogeneous sheath. It is found that in general rather distinct differences are observed except when the sheath is very thin.
THE CREEP OF ICE IN BENDING
Authors: Krausz A. S.
Published: April 2011

Observations were made on the creep behavior of columnar ice beams of different thicknesses subjected to repeated and reversed loading. More than half of the beams tested showed unusual creep behavior. During transient creep the strain rate increased to a maximum value and decreased only thereafter. It was established that this behavior was not a permanent property of ice. On reloading, the same beams exhibited normal creep behavior. For the conditions of the experiments, the deflection was very sensitive to the thickness of the beams. It was found that the neutral axis was located at the center of the beam when the maximum strain was less than 1%.
A STUDY OF TRANSATLANTIC RADIO PROPAGATION MODES AT 41.5 MC/S
Authors: Hagg E. L. , Rolfe W.
Published: April 2011

Both great-circle and off-path propagation modes have been investigated on a transatlantic path. Measurements of signal strength and azimuthal bearing were made at Ottawa, Canada, on the 41.5-Mc/s BBC TV sound channel transmissions during the winter months of 1957–58. The predominant signal was found to be a ground (land or sea) sidescatter signal arriving about 35° to the south of the great circle path. The presence of this signal can be explained qualitatively by ground-level focusing near the intersection of the receiver and transmitter skip distances.A secondary off-path signal, arriving about 7° to the north of the great circle path, was observed. This signal may be ionospheric sidescatter from irregularities in the auroral zone. It is suggested that the ionospheric sidescatter is analogous to ground sidescatter since focusing is not restricted to ground level.It is shown that the method using the two-hop geometric great circle path is superior to the 2000-km control-point method for predicting monthly median transatlantic maximum usable frequencies during winter daytime when low to moderate transmitted power is used.
THE VACUUM VIBRATOR AS A SOURCE OF IONS FOR MASS SPECTROSCOPY
Authors: Venkatasubramanian V. S. , Duckworth H. E.
Published: April 2011

The metallic ions that are produced in the arc that occurs when a contact is broken in a vacuum have been studied. The energy spread amongst such ions is significantly smaller than for the ions produced in a vacuum spark. Also, the relative ionization efficiencies for both singly and doubly charged ions can be greatly different in the two cases. The vacuum arc may prove of use in solid-source mass spectroscopy.
RADIATION FROM A LINE SOURCE IN A UNIAXIALLY ANISOTROPIC PLASMA
Authors: Tuan H. S. , Seshadri S. R.
Published: April 2011

Two problems of radiation in a magnetized, incompressible plasma are investigated. The radiation characteristics of a line source of magnetic current are studied for the case in which the external magnetic field is infinite and oriented in a direction perpendicular to that of the source. The second problem that is treated is the radiation from a uniformly moving line charge. Two cases are considered, namely: (1) when the motion of the line charge is parallel and (2) when it is perpendicular to the direction of the external magnetic field. In each case it is found that there is a Cerenkov-type radiation for frequencies less than the plasma frequency. The frequency and the angular spectrum, as well as the total energy radiated per unit path length, are determined for both cases.