bluuebunny/crossref_metadata_2025 huggingface dataset:
A NOTE ON ADIABATIC FAST PASSAGE, AND SPIN TEMPERATURE AND ADIABATIC DEMAGNETIZATION IN THE ROTATING COORDINATE SYSTEM
Authors: Daniels J. M.
Published: April 2011

It is shown that the phenomenon of adiabatic fast passage in magnetic resonance, and the concepts of spin temperature in the rotating coordinate system and adiabatic demagnetization in the rotating coordinate system, are simply explained by considering as a unit a spin coupled to a quantized electromagnetic field. Adiabatic fast passage in forbidden transitions is also explained simply.
THE DECAY OF Sb125
Authors: Mann K. C. , Payne F. A. , Chaturvedi R. P.
Published: April 2011

The beta, internal-conversion, and gamma radiations of Sb125–Te125 have been examined with magnetic and scintillation spectrometers, and by means of beta–gamma and conversion electron–gamma coincidence techniques. The results lead to self-consistent transition intensities, and completely support the decay scheme and spin–parity assignments of Narcisi (1958). There is evidence that a considerable fraction of the 633-keV radiation may originate at the 668-keV level. There is also supporting evidence for the 62-keV transition reported by Chandra and Pandharipande (1963).
ISOTOPE SHIFT OF THE NITROGEN ABSORPTION BANDS IN THE VACUUM ULTRAVIOLET REGION
Authors: Ogawa M. , Tanaka Y. , Jursa A. S.
Published: April 2011

The vibrational isotope shift of the nitrogen absorption bands has been studied in the 830–1000 Å region. A 3-meter normal-incidence vacuum spectrograph was used with the helium continuum as background.According to our analysis, the vibrational quantum numbers assigned to the lowest observed vibrational levels for the various electronic states of N214 are as follows: [Formula: see text], 100 824 cm−1, ν = 0; (b 1Πu), 101 455 cm−1, ν = 1; (l 1Πu), 104 146 cm−1, ν = 5; [Formula: see text], 104 366 cm−1, ν = 0; (m 1Πu), 105 350 cm−1, ν = 5 ~ 7; (o 1Πu), 105 703 cm−1, ν = 0; [Formula: see text], 106 649 cm−1, ν = 4; (p 1Πu), 108 373 cm−1, ν = 9 ~ 10; [Formula: see text], 109 833 cm−1, ν = 11 ~ 12; [Formula: see text] 110 944 cm−1, ν = 10; (s ?), 116 688 cm−1, ν > 20; and (t ?), 118 486 cm−1,[Formula: see text]. The observed isotope shift for the bands [Formula: see text], 106 381 cm−1; [Formula: see text], 108 549 cm−1; (f ?), 110 196 cm−1; [Formula: see text] 110 664 cm−1; [Formula: see text], 112 777 cm−1; (h′ ?), 114 841 cm−1; (h″ ?), 116 820 cm−1; and [Formula: see text], 118 778 cm−1 increases in this order and shows that none of these bands corresponds to a (0, 0) band.
METEOR RADAR STATISTICS. I
Authors: Millman Peter M. , McIntosh Bruce A.
Published: April 2011

A backscatter, pulse-type, patrol radar has recorded meteor echoes continuously near Ottawa for the years 1958 to 1962 inclusive. Five-year mean hourly echo rates for each day in the year are presented for all echoes counted, a total of some seven million, and for echoes of duration [Formula: see text] seconds. The diurnal variations in hourly echo rates throughout the year are given as five-year means in five-day groups.
A SOLUTION OF THE FOKKER–PLANCK EQUATION FOR HOMOGENEOUS PLASMAS
Authors: Jankulak F. J. , Sobrino L. G. de , Tam Y. K. S.
Published: April 2011

The linearized Fokker–Planck equation for homogeneous and isotropic plasmas is solved by using the Raleigh–Ritz variational procedure. The problem is considerably simplified when only dominant terms in the ratio of the electron mass to the positive ion mass are taken into consideration. The results are compared with the solution of the Balescu–Guernsey–Lenard equation obtained by Rosenberg and Wu. The agreement of the solutions can be taken as a justification for the use of the Fokker–Planck equation for homogeneous plasmas.
THE K–LL AUGER SPECTRUM OF 79Au197
Authors: Wolfson J. L. , Baerg A. P.
Published: April 2011

The K–LL Auger spectrum of 79Au197 has been examined in a high-resolving-power beta-ray spectrometer adjusted for a linewidth of 0.1% in momentum. A source of 65-hour Hg197 was used. A six-line spectrum was observed consisting of the lines K–L1L1, K–L1L2, K–L1L3, K–L2L2, K–L2L3, and K–L3L3. The K–L1L3 line is noticeably wider than the others and the line may be interpreted as consisting of the two components 3P1 and 3P2. The energies of the lines are 51.78 ± 0.02, 52.42 ± 0.02, 54.20 ± 0.02, 52.95 ± 0.03, 54.81 ± 0.02, and 56.63 ± 0.02 keV respectively. The relative intensities found were, respectively, 1.00, 1.54 ± 0.11, 0.99 ± 0.09, 0.11 ± 0.03, 1.83 ± 0.13, and 0.75 ± 0.07. Neither the energies nor intensities are in complete agreement with the latest theoretical work.
STUDIES IN THE DECAY OF THE ACTIVE DEPOSIT OF ACTINIUM: I. ALPHA–GAMMA ANGULAR CORRELATION IN THE DECAY OF Bi211 (AcC)
Authors: Cothern C. R. , Connor R. D.
Published: April 2011

The α–γ angular correlation of the cascade Bi211(α, 6.27 MeV)Tl207*(γ, 350 keV)Tl207 has been found to be isotropic to within [Formula: see text].Accepting the spin and parity of the ground state of Tl207as 1/2+, a search was made for all reasonable spins and angular momenta, pure and mixed, which could yield an isotropic correlation. Shell-model predictions and other situations have been examined. No case of unmixed α-, unmixed γ-angular momenta satisfies the isotropy condition. Many other cases are found which do so, but only with the spin and parity of the excited state of Tl207 taken as 3/2+. It has been shown that 5/2+ does not yield an isotropic correlation. With one radiation mixed and the other pure, there are eight possible combinations which fit the observations. With both radiations mixed, there is an infinity of combinations of the two mixing parameters which lead to an isotropic distribution. The αk value of the 350-keV transition (0.175 ± 0.017) shows the γ ray in question to be 76% M1 and 24% E2. The present work is consistent with only one of the two possibilities given by Gorodetzky et al. (1962) from polarization–correlation work. Accepting this additional evidence it would appear that the most plausible interpretation is that of shell-model spins and parities with both radiations mixed, α—(λ = 3, 5), γ—(76% M1, 24% E2).
RAPID DETERMINATION OF AURORAL HEIGHTS
Authors: Brandy J. H. , Hill J. E.
Published: April 2011

A method using wide-angle cameras has been developed which reduces the time and labor required for the parallactic determination of auroral heights. The system consists of two wide-angle or "all-sky" cameras at a fixed separation of 21.65 km. Simultaneous photographs from the two stations are projected on a predetermined grid from which the parallax can be read directly. Heights on arcs and bands having well-defined borders can be found over a much greater length than before and with comparative ease. The system is particularly useful during the flight of rockets into aurora and for studies of height versus any other measurable property of aurora. The accuracy obtainable is approximately ± 3%.
SOME TEMPERATURE EFFECTS ON POSITRON ANNIHILATION IN METALS
Authors: MacKenzie I. K. , angstroth G. F. O. , McKee B. T. A. , White C. G.
Published: April 2011

Angular correlation of gamma rays from two-quantum positron annihilation has been investigated in seven metals: zinc, cadmium, indium, lead, tin, aluminum, and bismuth, over a range of temperatures from –150 °C up to their melting points. The distributions for lead, tin, aluminum, and bismuth show no more than the small variation with temperature expected because of the change in lattice volume. Zinc, cadmium, and indium display a large increase in the proportion of annihilations occurring with the valence electrons at higher temperatures. This observation and evidence of increased thermal scattering correspond to features reported for the solid–liquid transition. Consequently, it is suggested that these three metals exhibit some of the disorder properties of their liquid state as they are heated above room temperature. In addition to the continuous temperature dependence observed for these metals we find evidence of a small discontinuous change in the distribution for zinc. This occurs at a temperature midway between previously reported anomalies in the properties of zinc.
THERMAL EXPANSION OF SOLIDS AND THE TEMPERATURE DEPENDENCE OF LATTICE VIBRATION FREQUENCIES
Authors: Schauer Alois
Published: April 2011

It is shown that a close relation exists between the temperature coefficient of lattice vibration frequencies and the thermal expansion coefficient. The basic equations[Formula: see text](νi being the frequency of the ith mode of vibration, T the temperature, Ci the Einstein function of frequency νi, γ the Grueneisen parameter, and β the volume thermal expansion coefficient) are derived and discussed for various temperature ranges.
A PRECISION MEASUREMENT OF THE ENERGIES OF TRANSITIONS IN Hg198 AND Hg199
Authors: Kaye G. , Graham R. L.
Published: April 2011

The energies of the Hg199 50-, 158-, and 208-keV, and Hg198 676-and 1088-keV transitions have been measured. This has been done by comparing the momenta of the internal conversion lines of each transition with three conversion lines of the Hg198 412-keV transition, the energy of which has been previously measured with high accuracy. The comparison was made using the Chalk River π√2 β-ray spectrometer. From the momentum comparisons the following transition energies were obtained: Hg199, 49.828 ± 0.004, 158.370 ± 0.006, and 208.198 ± 0.007 keV; Hg198, 675.878 ± 0.018 and 1087.69 ± 0.03 keV.
LOW-TEMPERATURE RECOVERY OF DEFORMED ALUMINUM
Authors: Swanson M. L.
Published: April 2011

The isochronal recovery of deformed polycrystalline Al was measured from 4 to 300 °K by means of residual electrical resistivity measurements. A well-defined recovery stage was observed between 60 and 100 °K (stage IIA); it has also been observed after neutron irradiation, but not after electron irradiation (Sosin 1963). This stage was enhanced by increasing the deformation or introducing quenched-in vacancies, and was suppressed by impurity atoms. These results can be explained by di-interstitial migration. The recovery below 60 °K (stage I) amounted to approximately 5%, and was independent of impurity content or degree of deformation. Both stage I and stage IIA recovery were greatly increased by a prior deformation and low-temperature anneal. A similar increase was observed for Au. This enhancement was attributed to a change in deformation mechanism because of dislocation pinning, which resulted in the formation of a preponderance of interstitial defects.
MAN-MADE ELECTROMAGNETIC INTERFERENCE AT EXTREMELY LOW FREQUENCIES
Authors: Lokken J. E. , Shand J. A.
Published: April 2011

In the electromagnetic spectrum between 6 and 36 c.p.s. several classes of man-made noise have been observed in rural areas adjacent to cities. Their probable sources are suggested. In many Canadian semirural areas this interference, though appreciable, is not sufficient to prevent reception of natural electromagnetic background, most of which is believed to originate with tropical lightning and to be propagated as Schumann resonance modes in the earth–ionosphere cavity.
A GROUP-THEORETICAL TREATMENT OF ELECTRONIC, VIBRATIONAL, TORSIONAL, AND ROTATIONAL MOTIONS IN THE DIMETHYLACETYLENE MOLECULE
Authors: Hougen Jon T.
Published: April 2011

The Hamiltonian for the dimethylacetylene molecule is expressed in terms of a set of coordinates which allow a separation of the molecular wave function into an electronic part, a vibrational part, a torsional part, and a rotational part. Symmetry species are introduced which can be used to classify separately any one of the parts of the molecular wave function as well as the total wave function itself. These symmetry species correspond not only to the single-valued representations of the group proposed by Longuet-Higgins for the dimethylacetylene molecule, but also to double-valued representations of that group. The use of these symmetry species and of the corresponding selection rules is illustrated by the example of an optical transition which would correspond to a [Formula: see text] transition in the linear portion of the dimethylacetylene molecule.
CUMULATIVE YIELDS OF THE HEAVY FRAGMENTS IN THE THERMAL-NEUTRON FISSION OF 241Pu
Authors: Farrar H. , Clarke W. B. , Thode H. G. , Tomlinson R. H.
Published: April 2011

The relative yields of isotopes of xenon, cesium, barium, cerium, neodymium, and samarium formed by the thermal neutron fission of 241Pu have been obtained by mass spectrometric methods. The relative yields of the elements were normalized by means of the isotope dilution and isobaric techniques, and absolute cumulative yields were determined by summing the relative yields to 100%. The curve obtained for 241Pu is compared with other mass–yield curves. The general shape of this mass–yield curve is similar to that for 239Pu; yet the fine structure shows greater similarity to that for 235U thermal-neutron fission.
CAUSALITY REQUIREMENTS AND LINEAR FIELD EQUATIONS
Authors: Morris T. F.
Published: April 2011

The requirements of Lorentz and time-reversal invariance, causality, positive definiteness of the field energy, and a boundedness condition on the propagator are used to determine the possible forms of linear field equations through the determination of their Green's functions in momentum space. The classical definition of causality, no output before input, is applied to a scalar field and is shown to imply the uniqueness of the usual propagator for a spin-zero particle of discrete mass.The classical definition of causality is then replaced by one appropriate for quantum theory. An additional type of equation is possible, which represents a particle with a continuous distribution of mass.
COLLISIONS OF LONG-LIVED EXCITED IONS OF OXYGEN AND NITROGEN
Authors: McGowan William , Kerwin Larkin
Published: April 2011

The role of some excited ions in laboratory ion–molecule reactions has been investigated, and their possible importance in the upper atmosphere considered. The mass spectrometer techniques of Aston banding and of comparing I.P. curves of parent and product ions have been applied to studies of collision-induced dissociation and charge exchange of oxygen and nitrogen in their parent gas. In every case studied, cross sections depended markedly upon the presence in the ion beam of ions in metastable or long-lived radiative states. In order that an ion reach the collision region, it had to have a mean lifetime greater than 3 μsec.The a 4Πu and b 4Σg excited states of O2+ were identified in the collision[Formula: see text]Higher states of O2+, which have not as yet been identified spectroscopically, were found in the collision[Formula: see text]The thresholds of these new states are 23.9, 27.9, 31.3, and 34.1 eV with an uncertainty ±0.2 eV. From the collision-induced dissociation of N2+, the A 2Πu and the [Formula: see text] states have been identified. Also, the reported transfer of the ν = 3 level of the B [Formula: see text] to the ν = 14 level of the A 2Πu was found.The cross section for 10/01 charged exchange of N2+ in N2 exhibited a marked decrease as excited-state ions diluted the beam. The 10/01 collisions of N+ in N2 and O+ in O2 exhibited an increase in cross section as metastables were added to the parent ion beam. The 10/20 reaction of O2+ in O2 was also observed to depend on excited O2+ ions.
CLASSICAL THEORY OF PLASMA AND HELICON RESONANCES IN SOLIDS
Authors: Wallace P. R.
Published: April 2011

A classical self-consistent theory of the long-wavelength normal modes of electrons in solids in the presence of a constant magnetic field is developed, similar in concept to that of Bohm and Pines. It is found convenient, however, to emphasize current rather than density fluctuations. The essential approximations are the neglect of retardation effects, which puts an upper limit on the wavelength which can be treated, and the random-phase approximation.The cases considered are those of a single carrier, and two carriers of opposite sign, each described by an effective mass.An equation is found for the normal frequencies, which has a predominantly longitudinal (plasma) solution and one or two predominantly transverse (helicon) solutions, as the case may be. The associated current distributions and electric fields are calculated. The helicon modes are found to transmit circularly polarized fields. In the case of two carriers, there is one mode of each polarization.The relation of the transverse resonance of Mermin and Canel to the helicon modes is shown.
A NEW GAMMA TRANSITION FOLLOWING THE DECAY OF 2.4-MINUTE 108AG
Authors: Taylor H. W. , Eastwood T. A.
Published: April 2011

A low-intensity peak has been found at 1010 ± 30 keV in the gamma-ray spectrum of 2.4-minute 108Ag obtained with NaI scintillation spectrometers. Consideration of the source-to-crystal distance as well as the effects of absorbers and decay time shows that it is the full-energy peak of a 1010 ± 30 keV gamma ray emitted by 108Ag. Gamma–gamma coincidence studies indicate that this gamma transition occurs between a new level at 1433 ± 30 and the 433-keV level of 108Pd.
ASYMMETRY IN THE ELECTROSTATIC DISPERSION OF LIQUIDS
Authors: Ryce S. A. , Wyman R. R.
Published: April 2011

The division of an electrically charged drop into two drops is considered. It is shown that for symmetric division the surface energy and electric energy of the final state of the system are at a minimum only if the surface charge Q on the drop of radius R and surface tension γ is[Formula: see text]If, however, Q2 is a fraction of this value, asymmetric division leads to a minimum of the final energy terms.Results of the photographic observation of the division of charged water drops in paraffin oil support the theory, i.e. asymmetric division is observed. Symmetry is approached for higher charges on the drops.For the division of uniformly volume-charged drops the theory predicts symmetric division.Theoretical energy–asymmetry plots bear a strong resemblance to fission-yield curves. The validity of the application of the theory to the observed asymmetry in nuclear fission is discussed.
ON THE THEORY OF ALLOY SOLIDIFICATION IN A MAGNETIC FIELD
Authors: Youdelis W. V. , Colton D. R. , Cahoon J.
Published: April 2011

The degree of segregation in unidirectionally solidified ingots, chill-cast in magnetic fields up to 34 kilo-oersteds, has been determined for alloys of the aluminium–copper and bismuth–antimony systems. It is found that the chill-face segregation in aluminium–copper ingots is increased approximately 50% above the no-field ingots for a 34-kilo-oersted field. The effect is independent of field direction. A 13-kilo-oersted field decreases the chill-face segregation by 60% in ingots of the bismuth (rich) – antimony system. A theory based on the diffusion inhibition effect of the magnetic field (previously reported) is presented to explain the segregation change. By applying irreversible thermodynamic principles, it is shown that the segregation changes in the field-solidified ingots are a manifestation of the decreased entropy production of the diffusion, convective mixing, and viscous flow processes of solidification in a magnetic field. For the aluminium–copper ingots there is order-of-magnitude agreement between the observed segregation change and the decreased diffusion rate in the magnetic field.
HIGH-RESOLUTION RAMAN SPECTROSCOPY OF GASES: XVIII. PURE ROTATIONAL SPECTRA OF CYCLOPROPANE AND CYCLOPROPANE-d6
Authors: Jones W. Jeremy , Stoicheff B. P.
Published: April 2011

A high-resolution study of the rotational Raman spectra of cyclopropane and cyclopropane-d6 has yielded the values 0.66962 ± 0.00020 cm−1 and 0.46079 ± 0.00015 cm−1 for their ground-state rotational constants. From these values the C–C internuclear distance is determined to be 1.514 ± 0.002 Å.
HIGH-RESOLUTION STUDIES OF GAMMA-RAY SPECTRA USING LITHIUM-DRIFT GERMANIUM GAMMA-RAY SPECTROMETERS
Authors: Ewan G. T. , Tavendale A. J.
Published: April 2011

This paper describes the use of germanium lithium-drift p-i-n diodes as high-resolution γ-ray spectrometers. With these spectrometers we have obtained γ-ray resolutions of 2.05 keV at 122 keV, 4.0 keV at 1333 keV, and 5.5 keV at 2614 keV. Using the detectors as pair spectrometers for high-energy γ rays, we have obtained a resolution of 9.8 keV on a 7.6-MeV γ ray. The factors affecting the resolution of the detectors are discussed. Fano factors of ~0.4 have been observed. Efficiency curves are given for a 2.5 cm2 × 3.5 mm detector and for a 5 cm2 × 8 mm detector.The detectors have been used to make high-resolution studies of the complex γ-ray spectra from sources of 131Cs, 161Pm, 153Gd, 156Eu, 159Gd, 177Yb, and 226Ra. Results are reported for the energies and intensities of the γ rays observed in these studies.
A 2Δ–2Π TRANSITION OF SiCl
Authors: Verma R. D.
Published: April 2011

The unclassified bands of SiCl in the region 2830–2760 Å have been photographed at high resolution. The vibrational and rotational analyses of these bands are discussed. It is shown that the upper electronic state is 2Δ case (b) and the lower state is the ground state X 2Π. The principal molecular constants in cm−1 (except for re, which is in Å) for both the states of 28Si35Cl are as follows:[Formula: see text]A discussion on electron configurations is also given.
DELAYED PROTONS FOLLOWING 21Mg AND 25Si DECAY
Authors: McPherson R. , Hardy J. C.
Published: April 2011

The delayed-proton precursors 21Mg and 25Si have been produced by proton bombardment of targets of sodium, magnesium, aluminum, and silicon dioxide in the internal beam of the McGill synchrocyclotron. Half-lives of 118 ± 4 and 225 ± 6 msec respectively were measured, and a spin-parity assignment of (5/2)+ has been made to the ground state of 21Mg. Strong lines in the delayed-proton spectra have been attributed to decay of the expected first T = 3/2 states in 21Na and 25Al, fed by superallowed β transitions from the respective precursors 21Mg and 25Si.
THE NONLINEAR INTERACTION OF AN ELECTROMAGNETIC WAVE WITH A TIME-DEPENDENT PLASMA MEDIUM
Authors: Papa Robert J.
Published: April 2011

A one-dimensional, inhomogeneous model is used to describe the nonlinear interaction of a radio-frequency plane wave with a time-varying plasma medium. A monochromatic plane wave is normally incident upon an electron density profile where the electron density gradients are shallow compared to a wavelength. Changes in electron temperature and electron density are induced which continually alter the pattern of electromagnetic energy deposition into the medium. The electron energy relaxation time is much longer than the period of the electromagnetic wave, so that the electron temperature does not follow the rapid variations in the impressed field. A nonlinear constitutive relationship is derived relating the macroscopic current density to the impressed electric vector, assuming that the wave field is almost monochromatic in the medium. The time-dependent response of the plasma medium may be found by numerically solving the energy-balance equations and the continuity equation for the electron gas. The spread in frequency of the electromagnetic wave field due to the time-varying electrical conductivity may be computed by employing the WKB approximation as a solution to the wave equation for a time-varying medium. Graphs are presented which represent the time-dependent response of the electron temperature and electron density as a function of the incident r-f. field amplitude.
THE SOLAR AND EXTRAGALACTIC RED SHIFTS
Authors: Gillieson A. H.
Published: April 2011

A photon model is postulated whereby the peculiar nature of the observed solar red shift is explained, and by which the extragalactic red shifts are interpreted as caused not by the Doppler effect, but by interaction and consequent loss of energy of the photon in passing through the inhomogeneities of the gravitational field in space.
INVESTIGATION OF RELAXATION OSCILLATIONS IN THERMISTOR–CAPACITOR SYSTEMS
Authors: Morley G. A.
Published: April 2011

It is known that a thermistor displays negative resistance at low frequencies when biased with a current greater than turnover current. Thus, when shunted by a capacitance in this condition, sustained oscillations are possible. These oscillations range from a sinusoidal small-amplitude character, when the system is just above threshold for oscillation, to a strongly relaxational type when a large shunt capacitance is employed.The investigation involved a study of the dynamic properties of these oscillations and their relation to the static properties of the thermistor. The relevant thermistor parameters which were measured included the thermal time constant for which special very-low-frequency techniques were developed.The oscillations were studied over a wide range of capacitance covering the transition from sinusoidal to relaxational type. The voltage extrema and period were measured as functions of capacitance, voltage supply resistance, and operating point.An investigation was made of the features of the differential equations describing the behavior of the system, especially for limit cycles corresponding to relaxation oscillations. The asymptotic form of the cycles was derived for the case where the circuital time constant greatly exceeds the thermal time constant of the thermistor. The complicated nature of the equations precluded a solution in a closed form, and approximative methods were found to be necessary. However, in the case of sinusoidal oscillations of small amplitude, the period can be expressed exactly in terms of the system parameters (Burgess 1955b) and this result was confirmed experimentally.
OPTICAL OBSERVATIONS OF THE STARK EFFECT ON OH
Authors: Phelps D. H. , Dalby F. W.
Published: April 2011

The ultraviolet spectrum of the OH molecule has been obtained in electric fields up to 64 000 volts per cm. Stark line splittings, broadenings, and field-induced parity-forbidden transitions have been observed. The electric dipole moment of OH in its electronic and vibrational ground state (X2Π) has been determined to be (1.727 ± 0.02) Debyes. The dipole moment in the first excited vibrational state has been found to be about 4% lower.
THERMOMAGNETIC PROPERTIES OF SULPHIDE ORE FROM THE NORANDA AREA, CANADA, MEASURED WITH A MAGNETIC BALANCE
Authors: Schwarz E. J.
Published: April 2011

The instrument balances the force exerted upon a specimen in an inhomogeneous magnetic field by the force acting on a long magnet in a current-carrying coil while the temperature of the specimen is varied between 20 and 800 °C. The force on the specimen decreases strongly when the Curie temperatures of ferromagnetic minerals present in the specimen are reached upon heating. The results for a specimen of sulphide ore show good reproducibility in Curie temperatures and in the force acting on the specimen under identical conditions. Two ferromagnetic minerals are present with Curie points of 310 °C ± 4 (pyrrhotite FeS1+0.11) and 578 °C ± 4 (magnetite). The TRM of the pyrrhotite is unstable if the specimen is left in the geomagnetic field at room temperature; that of the magnetite is stable under similar conditions.
THE UNMATCHED GUARD METHOD OF MEASURING THERMAL CONDUCTIVITY: II. THE GUARDLESS METHOD
Authors: Laubitz M. J.
Published: April 2011

A new system for measuring thermal conductivity at high temperatures is described in detail. The system is based on the Unmatched Guard Method, and forms a limiting case of it. The system is easy to assemble and to operate; it has a fast thermal response, and gives results with an uncertainty of only ± 2.3%, and an imprecision of ± 1.5%. Results obtained with the new system on Inconel 702 agree very well with previous work.
THE ANOMALOUS STARK EFFECT OF FLUOROFORM IN THE ν6 = 1 VIBRATIONAL STATE
Authors: Costain C. C.
Published: April 2011

It is shown that the paper of Maes and Amat, which explains the anomalous frequencies of the ν6, J = 2 ← 1, K = 0 lines in CHF3 and CDF3 by taking into account a strong mixing of K = 0 and K = 2 levels, also predicts accurately the Stark effect of these transitions. In addition, the perturbing J = 2, K = ±2, l = ±1 level of the ν6 = 1 vibration of CHF3 has been found at the position they predict. Further examination of the ν3 + ν6, J = 2 ← 1 line has removed the uncertainty in the assignment of the ν3 + ν6 and ν2, J = 1 ← 0 transitions.
PHOTO-IONIZATION OF N2 IN THE 734–805 Å REGION
Authors: Cook G. R. , Ogawa M.
Published: April 2011

Absolute photo-ionization coefficients and ionization efficiencies of N2 have been measured in the 734–805 Å region using a 1-meter Seya–Namioka scanning vacuum monochromator with the Hopfield helium continuum as a background light source.The ion-current spectrum obtained has been compared with the absorption spectrum observed photographically. Nearly all of the absorption bands with higher energies than the first ionization potential showed ion-current peaks, indicating pre-ionization. However, their ionization efficiencies showed strong fluctuations whose magnitudes decreased toward the shorter wavelengths. The spectral regions with the lowest absorption coefficients (180–340 cm−1) beyond the first ionization potential showed the highest efficiencies, the values of which were about 80%. Efficiencies of bands with m[Formula: see text] of the Ogawa–Tanaka Rydberg series were much larger than those of the corresponding bands of the Worley third Rydberg series. The progressions (1) and (2) had a rather high efficiency of 70% which increased slightly with an increase of the vibrational quantum numbers of the upper electronic states.
CERENKOV RADIATION OF PIONS
Authors: Coombes Charles A.
Published: April 2011

The energy radiated by a nucleon as pions in nuclear reactions is calculated by classical methods in the dipole approximation. This leads to a Cerenkov-type radiation of pions. The results are in good agreement with the measured number and spectra of pions in high-energy cosmic-ray events.
THE EFFECT OF AN ENERGY-DEPENDENT RELAXATION TIME ON THE MAGNETIC PROPERTIES OF CONDUCTION ELECTRONS
Authors: Muir W. B.
Published: April 2011

It is shown that a conduction-electron relaxation time, τ, which is sharply energy-dependent near the Fermi energy, such that τ = τ0 everywhere except when [Formula: see text] where τ is assumed to be zero, will have a negligible effect on the electronic diamagnetism for all temperatures less than the degeneracy temperature of the electrons. This anomalous relaxation time is also shown to induce temperature-dependent reduction in the spin paramagnetism which becomes of the same order as the spin paramagnetism at liquid-helium temperatures. However, alloys in which the anomalous relaxation might be expected to exist exhibit a Curie paramagnetism. The net effect of the anomalous relaxation time is to reduce the observed susceptibility of the alloy by about 1% at liquid-helium temperatures.
SUR QUELQUES ANOMALIES DU SPECTRE DE ROTATION PURE DU FLUOROFORME DANS UN ÉTAT VIBRATIONNEL EXCITÉ
Authors: Maes Serge , Amat Gilbert
Published: April 2011

An interpretation is given for various anomalies reported by C. C. Costain concerning the rotation spectrum of CHF3 and CDF3 in the excited vibrational state ν6 = 1. These anomalies are related to an essential resonance between levels K = 0, [Formula: see text], and K = ± 2, l6 = ±1, this resonance being accidentally strong, particularly in the case of CDF3.
THE STABILITY OF A SELF-GRAVITATING SYSTEM WITH TWISTED MAGNETIC FIELDS
Authors: Sundaram A. K.
Published: April 2011

The stability of a gravitating plasma column surrounded by a vacuum has been investigated for the case where both uniform volume and surface currents are present in the plasma. Some general stability criteria have been obtained for long-wavelength perturbations and the disturbance-growth-rate curves have been drawn for different modes m. It has been found that the stability of gravitating plasma is increased by the effect of both uniform volume current and external axial field for a specific range of values of b12. Further, for certain critical values of b12 much greater than 1.3 it has been found that the instability sets in for the mode m = 1.Some general dispersion relations have also been derived for the cases: (i) when there are general magnetic field and current distributions; (ii) when the system is subjected to uniform and nonuniform angular velocities. In the case of axi-symmetric disturbances whose wavelengths are assumed to be very large, it has been found that the stability characteristics of the gravitating plasma are unaltered by the effect of uniform rotation.
EQUILIBRIUM FRACTIONS FOR AN OXYGEN BEAM (15–50 KEV) IN 17 GASES AND VAPORS
Authors: Wittkower A. B. , Rose P. H. , Bastide R. P. , Brooks N. B. , Hopwood L.
Published: April 2011

The equilibrium fractions of O−, O+, and O2+ have been measured from 15 to 50 keV for the charge-changing of an O+ beam in the following gases and vapors: hydrogen (H2), helium (He), nitrogen (N2), oxygen (O2), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), nitrous oxide (N2O), deuterium (D2), water (H2O), ammonia (NH3), methane (CH4), sulphur hexafluoride (SF6), butane (C4H10), 2,2-dimethylpropane (C5H12), carbon dioxide (CO2). The neutral fraction, O0, may be inferred from the results.
DETERMINATION OF THE MEAN FREE PATH OF SLOW ELECTRONS BY THE MEASUREMENT OF BACK-DIFFUSION IN HELIUM AND ARGON
Authors: Orient O. J.
Published: April 2011

In the theoretical examination of back-diffusion Varney found a relationship between the extent of the back-diffusion of electrons starting from the cathode and the distance to the cathode. When adequate conditions are ensured the dependence of back-diffusion on distance permits the determination of the mean free path of the electrons. A test device has been developed to measure back-diffusion as a function of the distance to the cathode, for electrons that have an energy distribution corresponding to the specified pressure and the field intensity. From the dependence on distance, mean free paths for helium and argon gases in the range from X/p = 0.5 volt/cm. mm Hg to X/p = 5 volts/cm. mm Hg have been determined. The results are in fair accordance with the mean free paths computed by Barbiere from electron-energy distribution values. Variances have been found, however, with Townsend's and Bailey's data, particularly in the case of argon, where the free path of electrons depends greatly on velocity.
MODIFIED SPHERICAL HARMONIC METHOD AND NEUTRON TRANSPORT PROBLEM WITH FINITE SPHERICAL CORE
Authors: Wilson S. J. , Sen K. K.
Published: April 2011

The modified double-interval spherical harmonic method developed in the earlier papers has been applied to the spherical analogue of the Milne problem for the half-plane to determine the neutron density as a function of position. The values of the "extrapolated end point" are compared with those obtained by Marshak using the single-interval spherical harmonic method.
HIGH-RESOLUTION VACUUM ULTRAVIOLET ABSORPTION SPECTRUM OF THE E 1Π ← X 1Σ+ TRANSITION IN CO
Authors: Tilford S. G. , Vanderslice Joseph T. , Wilkinson P. G.
Published: April 2011

The (0–0) and (1–0) bands of the E–X transition have been observed in absorption at high resolution. The analysis of the (0–0) band identifies the E state as 1Π, thus confirming recent theoretical calculations. Λ-type doubling of the order of 0.2–0.3 cm−1 is observed at medium J values. The much weaker (0–0) band of 13C16O was also observed and analyzed. The pertinent spectroscopic constants for the E state of 12C16O are as follows: T00 = 92 930.04 cm−1, B0 = 1.9645 cm−1, and D0 = 6.50 × 10−6 cm−1. For the 13C16O molecule the corresponding constants are: T00 = 92 929.62 cm−1, B0 = 1.8773 cm−1, and D0 = 5.94 × 10−6 cm−1.
ON THE SYMMETRIC S-STATE COMPONENT OF THE TRITON WAVE FUNCTION
Authors: McMillan Malcolm
Published: April 2011

Approximate forms of the symmetric S-state component of the triton wave function are found which are improvements on the well-known exponential and Irving functions. The method does not involve variational parameters; the functions are obtained from reduced Schrödinger equations found using the methods of Feshbach and Rubinow and of Morpurgo. Some properties of these equations and their solutions are given. The reduced equations are solved numerically for various phenomenological nucleon-nucleon potentials without hard cores, and the functions are presented graphically. The eigenvalves of the reduced equations differ from the experimental triton energy, as is to be expected if only the symmetric S-state component is considered, and in an effort to simulate the effect of the other components, the depth of the nucleon–nucleon potential is increased until the computed eigenvalues equal the experimental triton energy. The corresponding eigenfunctions are given graphically. The Coulomb radius of 3He has been calculated with each of the functions, and the values found are generally reasonable.
THE CHEMISORPTION OF NITROGEN ON POLYCRYSTALLIN TUNGSTEN WIRES
Authors: Rigby L. J.
Published: April 2011

Desorption spectra have been obtained for successively increasing amounts of nitrogen adsorbed on three polycrystalline tungsten wires at room temperature. Two β phases were desorbed, β1 with first-order kinetics and an activation energy of 73 kcal/mole and β2with second-order kinetics and an activation energy of 75 kcal/mole. Surface impurities such as carbon or thorium reduced the size of the β1 phase. Mass spectrometric evidence showed that the small α phase was adsorbed as molecules, and the β1 and β2 phases were adsorbed as atoms.
SENSITIZED FLUORESCENCE IN VAPORS OF ALKALI METALS: II. ENERGY TRANSFER IN POTASSIUM–ARGON COLLISIONS
Authors: Chapman G. D. , Krause L.
Published: April 2011

Sensitized fluorescence in potassium, induced by argon at pressures between 0.01 mm Hg and 350 mm Hg, was investigated to determine the cross sections for collisions of the second kind between potassium atoms in the 4 2P states and argon atoms in their ground states. The experiment was carried out at a potassium vapor pressure of 2 × 10−6 mm Hg at which there is no trapping of resonance radiation. The collision cross sections at very low argon pressures, at which the collision frequencies do not exceed one per average lifetime of the excited states, are Q1 = 10 × 10−15 cm2 for the 4 2P1/2 → 4 2P3/2 transition and Q2 = 7.2 × 10−15 cm2 for the 4 2P1/2 ←  4 2P3/2 transition. At higher pressures, where the collisions are much more frequent, Q1 = 1.8 × 10−15 cm2, Q2 = 1.1 × 10−15 cm2, and Q1/Q2 = 1.6, in exact agreement with the principle of detailed balancing. The variation of the collision cross sections with argon pressure is ascribed to different transfer mechanisms predominating in the various pressure regions.
MEASUREMENT OF SPIN-LATTICE RELAXATION AT 890 Mc/s BY A RESONANCE-DISPERSION TECHNIQUE
Authors: Carruthers J. A. , Rumin N. C.
Published: April 2011

A new technique has been used to measure the spin-lattice relaxation time of Cr+++ in K3Co(CN)6 at 890 Mc/s. The method depends on observing both the amplitude and phase of the audio signal developed at the modulation frequency in a bridge-type microwave resonance spectrometer. One or more modulation frequencies are used, depending on the value of the relaxation time and the degree of saturation employed. Although similar to the saturation technique, this method does not require knowledge of the power level or the linewidth, and is suited to measurements on weak lines. Results have been obtained for lines at 100, 300, 1 400, and 2 100 oersteds, using crystals containing 0.06% and 0.4% chromium. The values of T1 for the lower concentration are in the 20–30-millisecond range, but relaxation appears to be not equivalent to a single time-constant. For the higher concentration the relaxation times are shorter and there is a marked evidence of multiple time-constants.
ON THE OSCILLATIONS OF A WEAKLY INHOMOGENEOUS PLASMA
Authors: Krishan Som
Published: April 2011

Oscillations of a collisionless plasma in equilibrium with a magnetic field which is weakly inhomogeneous in one dimension are studied. The calculations are based on longitudinal oscillations, i.e. the electric vector is parallel to the wave vector. The procedure employed is to use Maxwell's equations and expand the velocity distribution function about its equilibrium value for finding the perturbation in the distribution. The dispersion relation so obtained is different from that of Rosenbluth et al. (1962). The system is stable for the small Landau growth rate (Landau 1946), which might become appreciable for wavelengths comparable with the Larmor radius, provided [Formula: see text], where k is the wave vector and ε is a small inhomogeneity parameter.
THE RANGES OF 133Xe AND 134Cs IONS IN TUNGSTEN SINGLE CRYSTALS AND TUNGSTEN OXIDE AT ENERGIES OF 40 AND 125 keV
Authors: Ball G. C. , Brown F.
Published: April 2011

When 133Xe and 131Cs ions of 40- or 125-keV energy are stopped in single crystals of tungsten, the tails of the range distributions are different, the Cs ranges being ~15% smaller. No significant difference exists in the ranges of these ions in amorphous WO3.
COLLISION-INDUCED ABSORPTION OF COMPRESSED GASES IN THE FAR INFRARED, PART II
Authors: Bosomworth D. R. , Gush H. P.
Published: April 2011

The induced spectra of compressed helium–argon and neon–argon mixtures, and of compressed hydrogen, nitrogen, and oxygen have been measured in the frequency region 20 to 400 cm−1. The far-infrared spectra consist of a translational branch and a rotational branch which overlap, except in the rare-gas mixtures where only the translational component exists. The latter is a broad band which extends from zero frequency to about 500 cm−1, with a maximum near 150 cm−1 in the room-temperature gas. In the case of hydrogen the translational branch is readily distinguished from the rotational branch because it lies at a lower frequency than the latter. In the case of oxygen and nitrogen the spacing between the rotational lines is small and the translational and rotational branches overlap completely.
GALACTIC HYDROGEN AS A HAZARD IN AURORAL SPECTROSCOPY
Authors: Montbriand L. E. J. , Tinsley B. A. , Jones A. Vallance
Published: April 2011

Hydrogen emissions from diffuse galactic nebulae in the Milky Way region have been found to interfere seriously at times with studies of the occurrence of auroral hydrogen emissions made with patrol spectrographs. Charts have been prepared in which the brightness of galactic hydrogen is plotted in galactic coordinates as contour lines of constant brightness in Rayleighs. This presents the information available from the astronomical literature in a form suitable for use in upper atmosphere spectroscopy.
SATELLITE STUDIES OF ISOLATED IONOSPHERIC IRREGULARITIES
Authors: Turnbull R. M. , Forsyth P. A.
Published: April 2011

Ground-based observations of the radio signals propagated through the ionosphere from artificial satellites provide useful information about ionospheric irregularities. The technique has been extended to include recordings of the relative phase of the radio waves received at two stations as well as the customary amplitude recordings. This additional information is useful in interpreting the records. In particular, when relatively isolated single irregularities occur, a rather complete physical description can be derived including the location of each irregularity in three dimensions and a quantitative electron-density profile for the irregularity.
ON THE DISSOCIATION OF PbF AND BiF MOLECULES
Authors: Singh Ran B. , Rai D. K.
Published: April 2011

True potential energy curves have been calculated for the A and X states of BiF and PbF molecules using the Rydberg–Klein–Rees (R.K.R.) method as modified by Vanderslice et al. It has already been shown that by fitting an empirical potential function to the actual potential (R.K.R.) curve of a state we can obtain an idea of the correct dissociation energy of the molecule in that particular state. The three-parameter Lippincott function has been used for this purpose. The resulting dissociation energies for the ground states of PbF and BiF are (2.4 ± 0.2) eV and (2.60 ± 0.2) eV respectively. In PbF a large number of band systems are known, two of which show predissociation in the upper excited state. It has been found possible to account for both of these predissociations in PbF as being due to the A state of the molecule.
SCATTERING AT THE JUNCTION OF TWO SEMI-INFINITE PARALLEL-IMPEDANCE PLANE WAVE GUIDES
Authors: Karjala D. S. , Mittra R.
Published: April 2011

This paper considers an arbitrary mode in a parallel-impedance plane wave guide to be incident upon the junction of this guide with another. This problem has been used in an earlier work as a model for v.l.f. propagation past a shoreline, but is also of more general interest. A mode-matching technique results in the exact solution, and explicit results for the mode coefficients of both the transmitted and reflected fields are given.
LIGHT SCANNING ON EXTERNAL SLEEVE DISCHARGE IN HALOGENS
Authors: Venugopalan M.
Published: April 2011

It has been verified that the Joshi effect (the photovariation, enhancement +Δi, and diminution −Δi of the discharge current i) in halogen-filled discharge tubes, excited by a transformer discharge of 50-cycle potentials using external sleeve electrodes, is associated with the electrode regions and predominantly with the high-tension (HT) electrode region. The techniques of (i) partial irradiation and (ii) varying the irradiated length of the discharge column starting from either electrode were used and the Joshi effect was observed with (i) a reflection galvanometer and (ii) a cathode-ray oscillograph. The effect of scattered light from the illuminated glass side of the discharge tube and the gas or vapor reaching either electrode was minimized by increasing the spacing of the electrodes and using low gas pressures.It has also been verified that the applied field is one of the factors that determine the magnitude and sign of the Joshi effect. The maximum magnitude of +Δi was observed at the breakdown value (in the dark) of the applied field; the reversal in sign of Δi and maximum magnitude of −Δi were attained by only a small rise in the applied field above that required for the breakdown of the system in the dark.
DIRECTIONAL STUDIES OF ENERGETIC COSMIC-RAY MUONS: ANISOTROPY OF GALACTIC COSMIC RADIATION
Authors: Bukata R. P. , Standil S.
Published: April 2011

The use of a pair of equatorially mounted, narrow-angle, high-energy particle telescopes to effect an experimental study of energetic, directionally selected muons at the University of Manitoba in Winnipeg, Manitoba, is described. Experimental results are presented which indicate anisotropics up to ~15% in the primary radiation above about 40 BeV arriving at the earth in or near the equatorial plane. Preferred arrival directions were found, the most prominent being given by a RA of 20.5 ± 1 hour. Evidence is also presented for the existence of a solar modulation of the primary radiation.
THE ELECTRIC AND MAGNETIC FIELDS IN A STRATIFIED FLAT CONDUCTOR FOR INCIDENT PLANE WAVES
Authors: Dosso H. W.
Published: April 2011

The electric and magnetic fields in the upper layer of a stratified flat conductor in the field of plane waves are studied. Expressions for the amplitude and phase of the components of the electric and magnetic fields are obtained and evaluated for various frequencies, angles of incidence, layer thicknesses, depths, and conductivities. The conductivities σ = 10−11 to 10−16 e.m.u. and the frequencies ƒ = 10−3 to 104 cycles/second considered are of interest in geophysics.