bluuebunny/crossref_metadata_2025 huggingface dataset:
The deconvolution of a mass spectrum
Authors: Weichert D. H. , Russell R. D.
Published: April 2011

The use of digital recording systems for mass spectrometers is rapidly expanding. The design of such systems is rather critical if subtle sources of error are to be avoided. This paper reports the theoretical considerations on which Weichert et al. (1967) based their design. The Fourier transform of the expected mass spectra is predicted, and a suitable transversal filter is constructed. An inadequate bandwidth will result in measurements which are area-sensitive, leading to errors unless the scan rate is extremely well regulated. This situation can also arise through excessive digital filtering as well as through an inadequate measuring system. It follows that Wiener optimum filters are not usually appropriate. The sampling rate represents a compromise between computational efficiency and noise rejection, since the noise is not normally band limited. The problem of resolving-power multiplication is considered.
Spectral analysis of pearls
Authors: Jones F. W. , Geldart L. P.
Published: April 2011

A method of analyzing pearls with an analogue computer is presented. Power density spectra of short, consecutive samples of data are obtained, and thus the time of occurrence of each frequency component during the event is determined. The relative power in each frequency component is also obtained.
Magnetic field leakage into a semi-infinite pipe
Authors: Latham R. W. , Lee K. S. H.
Published: April 2011

Various conditions near the end of a semi-infinite, perfectly conducting pipe with a perfectly conducting flange are critically examined with regard to their effects on the interior field when the pipe is exposed to a low-frequency magnetic field. This is accomplished by solving several pertinent boundary-value problems. The results of this investigation indicate that (1) the effect of removing the flange is about 34%, (2) the effect of inserting a resistive cap is to yield a "shielding ratio" similar to that in other low-frequency shielding problems, and (3) the effect of an extremely narrow annular slot in an otherwise perfectly conducting cap is surprisingly large.
High-temperature susceptibility of a Heisenberg ferromagnet using Green function theory
Authors: Dembinski S. T.
Published: April 2011

A new first-order decoupling recently proposed, which gave very satisfactory results for the low-temperature magnetization of a Heisenberg [Formula: see text] ferromagnet, is used here to calculate the high-temperature zero-field susceptibility series. The results are close to those known from the random-phase-approximation decoupling.
The b1Σ+–X3Σ− band system of SO
Authors: Colin R.
Published: April 2011

The 0–0, 1–1, 2–2, and 0–1 bands of the b1Σ+–X3Σ− transition of the SO molecule have been observed in the afterglow produced when COS + O2 is pumped rapidly through a microwave discharge. The two strongest bands, 0–0 and 1–1, which lie respectively at 9549.08 and 9626.13 Å, have been photographed at high resolution and have been analyzed. Using the known X3Σ− rotational constants, the vibrational and rotational constants of the 1Σ+ state (Tc = 10 509.97 cm−1) have been determined: ωc′ = 1067.66 cm−1, Bc′ = 0.70262 cm−1, and rc′ = 1.5005 Å. Rotational intensity distributions for 1Σ+–3Σ− transitions are discussed. The a1Δ state of SO is predicted to lie at T ~ 6350 cm−1.
Tabulation of glow-curve characteristics
Authors: Fleming R. J.
Published: April 2011

A tabulation of the expected variation of the intensity of thermoluminescence glow curves with temperature is presented, based on a recent analysis due to Kelly and Laubitz. The temperatures at which the intensity equals one-half, two-thirds, and four-fifths of the peak intensity, on both sides of the maximum emission, have been calculated for both first- and second-order kinetics, over a trap-depth range of 0.1–1.5 eV. A linear heating rate has been assumed, and the temperatures of maximum emission vary from 100 to 700 °K. It is hoped that other workers in the thermoluminescence area will thus be enabled to analyze experimental data accurately without recourse to digital computing facilities.
D(3He, γ)5Li reaction from 2 to 11 MeV
Authors: Bianco W. Del , Lemire F. , Lévesque R. J. A. , Poutissou J. M.
Published: April 2011

The 90° yield of the D(3He, γ)5Li reaction has been measured from 2.3 to 11.2 MeV 3He energy. No clear evidence of a level in 5Li has been found over this energy range. The upper limits for the resonance integrated cross section and gamma-ray width were estimated to be σint ~ 15 μb MeV and Γγ ~ 100eV, respectively.
Comment on approximate molecular orbitals. III. The 1sσ and 2pπ states of HeH++
Authors: Matcha Robert L. , Lyon William D. , Hirschfelder Joseph O.
Published: April 2011

The results and conclusions of a recent paper by Cohen, McEachran, and McPhee concerning a perturbation calculation of the ground-state energy of HeH++ are compared with those found in an earlier paper by Matcha, Lyon, and Hirschfelder, which treated the same problem using essentially identical variation–perturbation techniques with a more general trial function.
Krebs's model and Lindemann's melting law
Authors: Singh A. K. , Sharma P. K.
Published: April 2011

Lindemann's melting criterion for cubic metals is examined using Krebs's model for the lattice dynamics of metals by computing the ratio, xm, of the mean square displacement of thermal vibrations and the square of interatomic spacing at the melting temperature for a number of cubic metals belonging to different groups of the periodic table. This ratio has nearly the same value for elements of one particular group, but exhibits wide variation from one group to another. It is concluded that Lindemann's melting law is inadequate.
Electronic absorption spectrum of nickel acetate tetrahydrate
Authors: Narayana P. A. , Mehra A. , Venkateswarlu Putcha
Published: April 2011

The absorption spectrum of Ni(CH3COO)2∙4H2O has been studied at room temperature and at liquid nitrogen temperature. The interesting feature of the observed spectrum is the appearance of a double-peaked red band similar to those observed in aqueous solution and hexahydrated crystals of Ni2+. The various possible assignments of this red band are examined and the most likely assignment is found to be such that the lower wavelength peak corresponds to the transition to the 1E(D) level, while the higher wavelength peak corresponds to the 3T1(F) level. This assignment is confirmed by calculating the positions of these levels in the cubic field approximation with the values of the parameters B = 975 cm−1, C = 4B, and Dq = 845 cm−1 obtained from the positions of other observed bands. The fit obtained with the positions of the two respective peaks is found to be quite good. The spin-forbidden transition to the 1E state borrows its intensity through the mixing of the triplet character into the state and, by solving the spin–orbit matrices, it is found that the Γ3 (1E) state does contain an appreciable amount of triplet character (35%).
Auroral energy input rates from radio scintillation measurements
Authors: Forsyth P. A.
Published: April 2011

The refraction suffered by radio waves passing through a developing auroral form is used to estimate the rate of energy input required to create the form.
Scattering of light from entropy fluctuations in 3He–4He mixtures
Authors: Ganguly B. N. , Griffin A.
Published: April 2011

In 1957, Gor'kov and Pitaevskii showed that second sound in 3He–4He mixtures is strongly coupled into the concentration fluctuations, which, in turn, scatter light quite strongly (especially near the critical point). In this paper, we give a more complete analysis of the fluctuations in density, entropy, and concentration. Our discussion is based on the hydrodynamic equations of Khalatnikov, which assume that the 3He atoms move with the normal fluid, and for simplicity we omit all dissipative coefficients. If we limit ourselves to scattering from density and concentration fluctuations, our results for the first and second sound intensities agree essentially with those of Gor'kov and Pitaevskii. Near the critical point, second sound scatters light about six times more strongly than first sound does.
The magnetic interaction effect. II. Experiments on silver
Authors: Shoenberg D. , Templeton I. M.
Published: April 2011

The de Haas – van Alphen effect in silver has been studied by the modulation method for the field along directions close to [Formula: see text], for which there is a dominant central belly oscillation and a weak noncentral one of nearly equal frequency. The use of pickup coils parallel and perpendicular to the field enabled both the parallel and perpendicular components of dM/dH to be observed. The prediction of Part I that strong magnetic interaction should generate a relatively much stronger difference frequency for the perpendicular than for the parallel component was semiquantitatively verified, although the parallel component of this difference frequency appeared rather more strongly than predicted. This and other discrepancies with the theory, such as the observation of rather too strong beats between the two frequencies in the parallel component, probably occur because of departures from the ideal conditions assumed in the theory (ellipsoidal shape and perfect homogeneity). The results are briefly compared with those of Joseph and Thorsen (1965), who studied the perpendicular component of M by the torque method.
A study of magnetothermal and Shubnikov – de Haas oscillations in arsenic
Authors: Vanderkooy J. , Datars W. R.
Published: April 2011

Magnetothermal and Shubnikov – de Haas oscillations were observed in arsenic. The periods of the oscillations are in agreement with those from recent de Haas – van Alphen experiments that support the Lin–Falicov model of the arsenic Fermi surface. The ratio of oscillatory and non-oscillatory resistivities is of the magnitude predicted by Adams–Holstein theory. It is shown that, for the same sample material, the Dingle temperature of the Shubnikov – de Haas effect is larger than the corresponding temperature of the de Haas – van Alphen effect. The long-period oscillation is not observed in the Shubnikov – de Haas effect. Factors that could attenuate the long-period oscillation are considered. Variations in temperature in the magnetothermal effect are compared to calculated values determined from the amplitude of the de Haas – van Alphen torque oscillations.
Cerenkov radiation in a periodic laminar dielectric
Authors: Casey K.
Published: April 2011

The electromagnetic field produced when a charged particle traverses a periodic laminar dielectric medium in a direction normal to the laminations is determined. The field is the sum of an infinite number of the normal modes of the structure. The conditions under which the individual modes are radiative are discussed, and expressions for the field components and energy spectral densities of the modes are obtained. Numerical examples illustrate the behavior of the spectral densities and emission angles of the various modes with respect to the particle velocity and the degree of inhomogeneity of the medium. It is found that the total energy spectral density of the radiation is nearly equal to that of Cerenkov radiation in a homogeneous medium. The principal effect of the periodicity of the medium is to cause the emission to occur at several angles with respect to the direction of travel of the particle.
Optical-model calculation of the 9Be(3He, 3He)9Be elastic scattering
Authors: Park J. Y.
Published: April 2011

Optical-model analysis of the elastic scattering of 6.0- and 8.0-MeV 3He particles on 9Be is performed with and without spin–orbit coupling. Good agreements with data are obtained, indicating the applicability of the optical model in describing the elastic scattering of 3He particles from such light nuclei as 9Be. Inclusion of spin–orbit interaction is found to improve fits, especially at backward angles. Almost equally good results are obtained by volume or surface absorption, although surface absorption gives slightly better fits at 8.0 MeV. Parameters giving the optimum fits to the data are presented and several ambiguities in the potential are discussed.
Newton's gravitational constant
Authors: Rosen Gerald
Published: April 2011

The formula for Newton's gravitational constant [Formula: see text] follows from a previous conjecture by the author regarding quantized gravitational theory and the size of elementary particles. It is observed that this formula does not conflict with geophysical and astrophysical evidence. Moreover, this formula for Newton's gravitational constant has the desirable feature of exhibiting no dependence on the speed of light.
An investigation of hydrodynamic waves with a cylindrical microwave resonator. II. The oscillation and damping frequencies of the waves
Authors: Pike R. L. , Curzon F. L.
Published: April 2011

We have measured the oscillation and damping frequency of a simple rotationally symmetric gravity-surface tension wave on mercury, as a function of depth and surface diameter. The oscillation frequency is apparently affected by the curvature of the mercury meniscus, and is largest for clean surfaces. The observed damping frequencies are well predicted by a theory in which it is assumed that the free mercury surface is laterally immobile. In all cases measurements are made when the linearized Navier Stokes equations provide a valid description of the waves.
Hyperfine energy splitting of positronium measured in water
Authors: Iaci G. , Savio M. Lo , Turrisi E.
Published: April 2011

In order to investigate the behavior of positronium in water, magnetic quenching measurements have been performed at various temperatures from 0 to 45 °C and with applied fields up to 12.5 kG. From these measurements it has been possible to evaluate the effect of the water. In fact, while for the positronium-free atom in the ground state the hyperfine structure energy splitting is ΔW0 = 8.34 × 10−4 eV, for positronium in water we find two consistent values, ΔW = (6.32 ± 0.20) × 10−4 eV and ΔW = (7.30 ± 0.80) × 10−4 eV, obtained by considering the magnetic-field effect on the positronium component which decays by pickoff and on its decay rate.
Stability of a viscous liquid flowing down a flexible boundary
Authors: Gupta A. S.
Published: April 2011

The stability characteristics of a viscous liquid flowing down a flexible boundary are investigated for long-wave disturbances. In the case of a normally compliant boundary which resembles a thin stretched membrane resting on an elastic foundation with viscous damping, it is found that the critical Reynolds number Rc increases with the elastic parameter. For a boundary showing purely tangential compliance, Rc is found to depend on the phase shift between the oscillation of the shear stress and tangential deformation.
Shell-model calculations in the 16O region with the Tabakin potential
Authors: Takacsy N. de
Published: April 2011

Shell-model calculations are performed with the Tabakin potential for the simplest configurations in 14N, 15O, 16O, 17O, 18O, and 18F. The second-order ladder diagrams are calculated in relative coordinates, using harmonic oscillator intermediate states; all second-order corrections to the effective interaction are included.
Diffraction by a wide unidirectionally conducting strip
Authors: Jull E. V.
Published: April 2011

The diffraction of a plane electromagnetic wave by an infinitely long, unidirectionally conducting strip is formulated as a Wiener–Hopf integral equation and is solved asymptotically for a wide strip by transform techniques. In addition to the diffracted fields produced by a perfectly conducting strip, surface-wave excitation and scattering at the edges and interaction between the ends of the lines of conductivity appear in the solution. These effects are illustrated by numerical results of the scattering cross section at normal incidence for various directions of conductivity.
Study of moving striations in plasmas. IV. Electron-energy transfer and the determination of the electron thermal relaxation length
Authors: Drouet Michel G.
Published: April 2011

A general expression relating the small variations of the electron density, the electric field, and the electron temperature in a positive column is derived. It is shown that measurements of the variations of these plasma parameters in moving striations of small amplitude and in particular of the relative phase of these variations can be used to determine the thermal relaxation length for the electrons in a positive column.The value of the electron thermal relaxation length for a positive column in neon, with a pressure of 1 Torr, discharge current 26 mA, discharge-tube diameter 6.5 cm, is found to be approximately 1 cm.
Surface potentials in vacuum-deposited MIS structures
Authors: Brodie D. E. , Kawaliw I. , Tokarsky R.
Published: April 2011

The high-frequency capacitance method has been used to study surface states in vacuum-deposited structures of Au–SiOx–CdSe, Au–CaF2–CdSe, and Au–SiOx–CaF2–CdSe. Monoenergetic surface states (0.04 eV) are observed in the latter structures and these states are observed to be unstable. Zero bias bending at the surface of the semiconductor has been evaluated by calculating the surface potential ψs as a function of the applied bias.
Planar antenna arrays above a stratified medium
Authors: VanKoughnett A. L.
Published: April 2011

Infinite uniform planar arrays of linear antennas are considered. It is shown that the antenna impedance and current distribution can be found from a straightforward generalization of previous analyses when an array is placed above any medium that is homogeneous in planes parallel to that containing the array.
On the thermodynamics of a relativistic scalar fluid
Authors: Tam Kwok-Kee
Published: April 2011

Some relativistic, thermodynamical relations for a system of particles interacting through a classical, scalar field are derived.
Phonon mean free paths from magneto–thermal-conductivity measurements
Authors: Brock J. C. F. , Huntley D. J.
Published: April 2011

Thermal conductivity measurements on lanthanum cobalt nitrate in the temperature range 1–5 °K and in magnetic fields up to 20 kOe are described. The data are analyzed in terms of a simple model in which phonons that are on speaking terms with the paramagnetic cobalt ions are completely removed from the heat flux; this allows one to calculate the mean free path of these phonons due to other processes. In crystals of low thermal conductivity the interacting phonons are not completely removed from the heat flux and the model, extended to include this, allows one to determine the strength of the spin–lattice interaction.
Effect of the lifetime of the intermediate 5Li state in the 6Li(3He, αp)4He reaction
Authors: Reimann M. A. , Martin P. W. , Vogt E. W.
Published: April 2011

A cylindrical asymmetry about the direction of motion of 5Li has been seen in the breakup of the ground state of this nucleus observed as an intermediate state in the reaction 6Li(3He, pα)4He. Measurements were made at bombarding energies of 1.00, 1.25, and 1.50 MeV with isotopically enriched LiF targets using a two-dimensional analysis technique. We explain both the rough magnitude of the asymmetry and its qualitative energy dependence in terms of a simple semiclassical model. In this model the origin of the asymmetry is associated with the short life of the 5Li intermediate state and with the memory retained by the proton during this short life of its "localization" at the time of formation of 5Li.
The second-order phase transition and the Ehrenfest relations
Authors: Grindlay J.
Published: April 2011

A new derivation of the Ehrenfest relations for a second-order phase transition is given. Two examples of the second-order phase transition of the type envisaged by Ehrenfest are described, one a superconducting and the other a ferroelectric phase transition.
The effects of end holes and the glass tube on average electron number density measurements in a TM010 cavity
Authors: Gregory B. C.
Published: April 2011

The importance of end holes and the glass tube in TM010 mode measurements of the average electron number density in cylindrical plasmas is evaluated.
The dielectric constants of finite ionic crystals
Authors: Grindlay J. , Wong H. C.
Published: April 2011

Expressions are derived for the low-temperature behavior of the dielectric constants of an ellipsoid of diatomic ionic material with CsCl symmetry for the case of deformable ions. The derivation is based on an extension of the method used previously for the rigid ion model. Two errors appearing in this earlier work are corrected. We conclude that within the quasi-harmonic approximation there are no shape effects in the dielectric constants of this model.
Numerical Hartree–Fock results for the atoms helium to radon
Authors: Fischer Charlotte Froese
Published: April 2011

Numerical Hartree–Fock results for the atoms helium to radon are reported.
Energy levels of excited in the decay of the isomeric pair and
Authors: Monaro S. , Barrette J. , Boutard A.
Published: April 2011

The γ-ray spectra accompanying the decay of 96gTc (4.3 d) and 96mTc (52 m), produced in the reactions 96Mo (p, n) 96Tc and 97Mo (p, 2n) 96Tc, have been studied with lithium-drifted Ge detectors.Gamma rays (relative intensities are in parentheses) of 314.2 ± 0.2 (2.4), 316.3 ± 0.2 (1.5), 434.8 ± 0.4 (0.8), 460.2 ± 0.4 (0.48), 568.9 ± 0.4 (.95), 778.2 ± 0.2 (100), 812.5 ± 0.2 (83), 849.8 ± 0.2 (98), 1091.3 ± 0.4(0.9), 1126.8 ± 0.3 (15.3), 1200.0 ± 0.4 (0.41), and 1497.7 ± 0.5 keV (0.081), plus several other very weak lines, have been observed in the decay of 96Tc (4.3 d). Several transitions never previously reported were found in the decay of 96mTc (52 m). All but four of these transitions could fit already known excited levels in 96Mo at 778.2, 1497.9, 1628.0, 1869.6, and 1978.3 keV, whereas the placing of the remaining 616.1-, 966.6-, 1096.6-, and 1816.2-keV gamma rays required the existence of a new level in 96Mo at 2594.5 keV.In view of the results obtained from the study of the decay of the 96Tc isomeric pair, it was considered very desirable to reinvestigate the decay of 96Nb to levels in 96Mo. The 96Nb source was produced in the reaction 96Zr (p, n) 96Nb. Ge(Li) detectors were again employed and gamma–gamma directional correlation measurements were performed with two NaI(Tl) crystals, a fast coincidence circuit, and a multiparameter analyzer to record the data.The experimental directional correlation coefficients of the 1200.1–778.2, 1200.1–460.1, 778.2–460.1, 1091.4–778.2, 1091.4–568.7, and 778.2–568.7 keV cascades are[Formula: see text]respectively.These values seem to be compatible with spin assignments of 4+, 3+, and 5+ for the 1869.6-, 1978.3-, and 2438.4-keV levels in 96Mo respectively.
Relations between electronegativity and potential energy in the alkali metal molecules
Authors: Szöke S. , Baitz E.
Published: April 2011

Potential energy functions can be constructed by the aid of parameters other than spectroscopic constants to render the possibility of linking different areas in chemical physics. By using a formula connecting force constants of diatomic molecules and bonds in polyatomics, a potential energy function can be obtained by replacing some of the spectroscopic parameters by expressions based on the use of electronegativities.
Spectrum of the night airglow between 3 and 4 microns
Authors: MacDonald R. , Buijs H. L. , Gush H. P.
Published: April 2011

The spectrum of the night airglow has been measured between 3 and 4 μ at a limit of resolution of 4 cm−1, the observations being made at an altitude of 95 000 feet. The most prominent feature of the spectrum is the Δν = 1 sequence of hydroxyl bands. An intensity analysis of the rotational structure yields a rotational temperature of 234 °K. In addition, the ν3 band of methane near 3000 cm−1 and the ν3 band of CO2 near 2350 cm−1 appear in emission.
Decay of 134Cs
Authors: Nagpal T. S.
Published: April 2011

The gamma ray spectrum and the conversion line spectrum of 134Cs have been investigated using lithium-drifted detectors. The 563–569 and 796–802 keV doublets have been completely resolved for the first time. The energies in keV, relative intensities in percent per disintegration, and dominant multipolarities of the transitions observed are: 475.57(1.6%, E2); 563.06(8.6%, E2); 569.30(13.3 %, M1); 604.83(97.5%, E2); 796.02(87.0%, E2); 801.90(7.9%, E2); 1038.19(1%, M1 + E2); 1168.40(2%, E2); 1365.40(3.5%, E2); and 1580(0.03%, M1 or E2). The present results are consistent with the levels in 134Ba at 0(0+), 605(2+), 1168(2+), 1401(4+), 1580([Formula: see text]), 1643(3+), and 1970(4+) keV. There is no evidence for the previously reported levels at 923, 1062, 1374, 1770, and 1854 keV. The intensity of the beta-feeds to the levels at 1970, 1643, 1580, and 1401 keV respectively are 24.7%, 1.6%, 0.03%, and 73.7%, as computed from the intensity balance of levels in 134Ba. A modest attempt at comparison between the observed excited levels and theoretical predictions is made.
Scattering from a thin sheet obstacle on a curved surface
Authors: Wait James R.
Published: April 2011

The problem of the reflection and transmission from a thin conducting sheet, erected over a cylindrical surface, is considered. The sheet is characterized by a jump condition on the tangential magnetic field. The geometry is restricted to the case when the thin sheet is in a plane normal to the cylindrical impedance-type boundary. Although the problem is two dimensional, the conductivity of the sheet may be nonuniform in the radial direction. It is shown that this nonuniformity results in appreciable conversion between the creeping wave type modes on the cylindrical surface.
Modification of scattering of waves by central loading
Authors: Chen Chin-Lin
Published: April 2011

The problem of the scattering of a plane wave by a long, thin, perfectly conducting wire is studied. The scatterer is loaded at its center by a lumped element. The effects of the loading on the scattering of waves are investigated. Numerical results are obtained for the case of normal incidence. The results show that for relatively short wires, the back-scattering cross sections may be modified effectively by central loading, while for longer wires, the modification is rather difficult to achieve. To nullify the back-scattering cross section completely, it is necessary to use active loading if kh > 3.6. A physical explanation is also presented.
Levels in 143Pr populated in the decay of 143Ce
Authors: Gregory P. R. , Schellenberg L. , Sujkowski Z. , Johns M. W.
Published: April 2011

Experiments using Ge(Li) and Nal(Tl) detectors singly and in a 2-parameter coincidence arrangement have been carried out to establish the role of a number of weak transitions in the decay of 143Ce. Twenty-six of the twenty-seven observed γ rays have been placed in a decay scheme with levels at 57.4, 350.6, 490.2, 721.8, 739.9, 847.9, 937.3, 1059.8, (1156.5), 1160.1, 1381.6, and 1397.4 keV. The K-conversion coefficients of the 293 and 350 keV transitions, measured with a Si(Li) detector, are 0.10 ± 02 and 0.024 ± 0.03 respectively.
The effects of nonuniform electromagnetic fields on the dielectric properties of crystals
Authors: Beaulieu A. J.
Published: April 2011

All the treatments of the interaction between electromagnetic radiation and phonons in ionic crystals assume that the electromagnetic field can be considered as uniform. With the very strong absorption present in such crystals this assumption leads to serious errors for all finite angles of incidence. Taking into account the nonuniformity of the field leads to the conclusion that significant interaction with the LO modes exists even in crystals of cubic symmetry, contrary to all other theoretical models assuming the uniformity of the electromagnetic field.
Transcription de la quasi-particule dans l'espace ideal et la méthode des bosons
Authors: Simard P. A.
Published: April 2011

A transcription of the quasi-particle into the ideal space is written in such a way that all the terms which contribute for the three quasi-particles system in QTD approximation can be found. Canonical transformations between the ideal quasi-particles are studied. An application to one shell is done with the result that the boson method gives exactly the same spectra as the Kuo method.
Vacuum polarization and D-wave α−α scattering
Authors: Kermode Mark W.
Published: April 2011

The D-wave phase shifts for α−α scattering at low energies are obtained from (i) new analyses of the differential cross sections and (ii) the effects of vacuum polarization. The results are −0.4° (−0.4°), −0.2° (−0.4°), +0.2° (−0.4°), −0.2° (−0.2°), and 0.3° (0.2°) for the center-of-mass energies 0.3, 0.425, 0.5, 0.75, and 1.0 MeV, respectively. It is felt that these results are significant.
Ionization increases associated with the small solar proton events of 5 February 1965 and 16 July 1966
Authors: Hewitt L. W.
Published: April 2011

Observations of partial reflections from the ionosphere at vertical incidence at 2.66 MHz have been made at Resolute Bay, geographic latitude 74.7 °N, since September 1963. By measuring the amplitudes of the ordinary and extraordinary backscattered waves information is obtained about electron number densities in the lower ionosphere. The results presented in this paper show that the partial reflection technique is more sensitive than most other ground-based experiments for the detection of D-region ionization increases associated with small solar proton events. Results obtained by the partial reflection experiment during the events of 5 February 1965 and 16 July 1966 are presented and compared with VLF and satellite observations.
A finite formulation of quantum electrodynamics
Authors: Eoll Christopher K.
Published: April 2011

A recent finite formulation of field theory is applied to quantum electrodynamics. The basic assumptions of the formulation are Bogoliubov causality and TCP invariance of the S-operator; interpolating fields are never used.Ultraviolet divergences never appear in the calculations, and there is manifest Lorentz covariance at every stage.In particular, the calculation of the proper third-order vertex is carried through.
Continued fraction representation for slow neutron scattering
Authors: Sears V. F.
Published: April 2011

Mori's continued fraction representation for calculating autocorrelation functions of dynamical variables is applied to the problem of slow neutron scattering by simple classical liquids. In particular, the first few "long-time" approximations are evaluated for the velocity autocorrelation function and for the incoherent and coherent scattering functions. In this way, many of the standard results of slow neutron scattering theory are obtained without having to make any of the ad hoc assumptions which usually enter the derivation of these results. In addition, the continued fraction representation provides a natural method of extending these results to higher order. Numerical calculations are made for liquid argon and compared with available experimental data and with Rahman's machine computations.
Stability conditions for displacement processes in porous media
Authors: Scheidegger A. E.
Published: April 2011

A general discussion is presented of the possibility of the development of a steady state in frontal displacement processes with and without "fingers" in porous media. It is shown that, based on the theories available to date, such displacement processes always appear to be unstable; i.e., the "length" of the "front" over which the transition from the displaced fluid to the displacing one occurs, grows indefinitely.
Sensitized fluorescence in vapors of alkali metals. XI Energy transfer in potassium–rubidium collisions
Authors: Hrycyshyn E. S. , Krause L.
Published: April 2011

Sensitized fluorescence in rubidium vapor, induced by collisions with excited potassium atoms, was investigated to determine the total cross sections for inelastic collisions between excited potassium atoms and rubidium atoms in their ground states. The collision cross sections for the various excitation transfer processes are as follows: Q12′ (K42P1/2 → Rb52P3/2) = 40 Å2, Q22′ (K42P3/2 → Rb52P3/2) = 27 Å2, Q11′ (K42P1/2 → Rb52P1/2) = 2.7 Å2, and Q21′ (K42P3/2 → Rb52P1/2) = 1.9 Å2. The partial pressure of potassium vapor in the K–Rb mixture was kept largely below 10−5 mm Hg to eliminate effects due to the trapping of potassium resonance radiation.
Distorted-wave Born approximation analysis for the reaction 12C(p,d)11C at 100 MeV
Authors: Li T. Y. , Mark S. K.
Published: April 2011

A distorted-wave Born approximation analysis of the 12C(p,d)11C reaction at 100 MeV has been performed by using the local-energy approximation for the finite-range correction. The neutron was assumed to be picked up from a bound state in a real Saxon–Woods well. The proton potential was fixed and a search was made to extract the deuteron optical potential parameters by fitting the angular distribution of the ground-state transition. Analysis of the excited states was carried out with all potential parameters fixed. Fairly good agreement with experiment has been obtained for the ground state, the 2.0-MeV excited state, and the 4.80-MeV excited state. Transitions to the 4.31-MeV state and states in the 6.9-MeV region were discussed. The spectroscopic factors extracted from experiment were generally smaller than those predicted by Cohen and Kurath, based on the intermediate-coupling shell model. The deuteron optical potential obtained is fairly reasonable with a real well depth slightly deeper than the expected value deduced from the elastic scattering of nucleons.
Directional effects of sputtering of a single gold crystal under bombardment by heavy ions
Authors: Wijngaarden A. van , Reuther E. , Bradford J. N.
Published: April 2011

The (111) surface of a single gold crystal was bombarded by monoenergetic ion beams of 1H, 4He, 11B, 14N, 20Ne, and 40Ar in the energy range 10–60 keV. The total positive charge liberated from the crystal surface under the ion bombardment was studied as a function of crystal orientation. The yield showed strong minima when the ion beam entered the crystal along the low index directions. The angular full width at half depth of these minima was studied as a function of energy and atomic number of the projectiles. The results are in good agreement with a theory based on a 1/R2 ion-atom potential.
A self-consistent investigation of Smith–Purcell radiation from a narrow tape helix
Authors: Neureuther A. R. , Mittra R.
Published: April 2011

The interaction of a modulated electron beam and a narrow tape helix is considered using a confined flow model for the beam. With this model, the analysis is self-consistent in that it takes into account the first-order effects of the interaction on the beam. The interaction is studied by means of complex waves on the composite system of the beam and the helix. The role of these waves is established in part on the basis of their complex wave numbers which are solutions of the appropriate determinantal equation. Although coupling similar to that used in traveling wave tubes is considered initially, the investigation concentrates on coupling which can be used to produce Smith–Purcell radiation. The results of the numerical evaluation of the wave numbers demonstrate that for the latter type of coupling, the modulation changes very slowly along the length of the interaction. This establishes the heretofore questionable validity of the prescribed source model for evaluating the interaction of a modulated electron beam and a narrow tape helix. Similar results are expected to hold for other interaction geometries.
A study of nuclear matter using separable potentials
Authors: Hodgson R. J. W.
Published: April 2011

The saturation properties of nuclear matter are determined using three different separable potentials. Results found using both second-order Hartree–Fock and an approximate reaction matrix are compared. In the latter method the angle-average approximation is examined. Calculations using the reaction matrix are straightforward and are found to be relatively insensitive to the potential forms and parameter values as long as the low-energy scattering data is satisfied.
On the interpretation of laser interferometer fringe patterns
Authors: Williamson J. H. , Medley S. S.
Published: April 2011

The frequency response of the laser interferometer is shown not to be limited by the Q-factor of the external resonator. However, at high fringing rates, the familiar Fabry–Perot fringes develop subsidiary maxima which make the fringe count liable to misinterpretation. This effect is minimized by using an external resonator with large losses. A passive technique employing an eighth-wave plate is described for determining the direction of change in the optical length directly from the fringe pattern.
Lattice dynamics of heavy rare-gas solids
Authors: Gupta N. P. , Gupta R. K.
Published: April 2011

Phonon spectra, dispersion curves, and the specific heat of frozen argon, krypton, and xenon have been studied using a quasiharmonic central force rigid-atom model with interactions up to eighth neighbors. The effect of zero-point vibration is included by an iterative method and a modified Buckingham potential is used. There is reasonable agreement between theoretical and experimental results. A number of possibilities for the improvement of results have been discussed.
"Self-field" limiting of Josephson tunnel current
Authors: Mahutte C. K. , Leslie J. D. , Smith H. J. T.
Published: April 2011

As was first predicted by Ferrell and Prange, the Josephson tunnel current is limited to a strip of width approximately 2λJ, where λJ is the Josephson penetration distance, along the edges of the junction due to the magnetic field produced by the tunnel current itself. Using the symmetric geometry of Owen and Scalapino, we have investigated the maximum zero voltage d.c. current, I0, in a zero applied magnetic field of Sn–SnO–Sn junctions with widths W ~ λJ and various lengths L. The experimental data is compared with the theory of Owen and Scalapino by plotting (LI0)/(2λJWJ1) versus L/λJ, where J1 is the tunnel current density without self-limiting. The results are in reasonable agreement with the theory, except that I0 tends to be less than predicted. However, in most junctions the usual Fraunhofer pattern of maximum zero voltage d.c. current versus applied magnetic field is skewed, and better agreement with theory is obtained if the maximum zero voltage d.c. current in a magnetic field is used instead of I0.
Design of high homogeneity inside-notch-corrected superconducting solenoids
Authors: Atherton David
Published: April 2011

A graphical technique is described which facilitates the design of high homogeneity solenoids corrected to sixth order by a notch on the inner surface of the coil.
Synchrotron radiation from single electrons gyrating in a magnetoactive plasma
Authors: Fung P. C. W.
Published: April 2011

In this paper, the incoherent synchrotron radiation power emitted by relativistic electrons gyrating in a cold magnetoactive plasma is rederived, correcting errors which have occurred in the past literature. One can specify the background plasma by the quantity A = ωp2/ωH2 (ωp is the angular electron plasma frequency and ωH is the angular electron gyro-frequency), i.e. the relative importance of the plasma frequency to the gyro-frequency. The general spectral features of synchrotron radiation from single electrons radiating in plasmas of large [Formula: see text] and small [Formula: see text] are discussed with the aid of a number of numerical examples.
Phase shift for total reflection from a bounded dielectric layer
Authors: Wait James R. , Spies Kenneth P.
Published: April 2011

The reflection of horizontally polarized electromagnetic waves from a stratified lossless dielectric region is considered. The region consists of two homogeneous half-spaces separated by a transition zone with a linearly varying permittivity. For angles of incidence sufficiently near grazing, it is shown that the magnitude of the reflection coefficient is unity, but the phase shift on reflection depends on the width of the transition zone in addition to the permittivity gradient. Some numerical results for the phase shift are given and discussed in relation to various limiting situations.
Electron spin resonance of Mn2+ impurities in monticellite
Authors: Danilov A. G. , Manoogian A.
Published: April 2011

The electron spin resonance of Mn2+ impurity ions in natural crystals of monticellite, MgCaSiO4, was studied in the 9.4 GHz and 35 GHz microwave frequency ranges, and at room temperature. Four magnetic complexes of manganese were observed, and these were found to degenerate into two in the (010) crystallographic plane. The magnetic field separations of the spectral lines along the principal axes of the crystalline electric fields were the same for all four complexes. The resonance lines were fitted to a spin Hamiltonian of orthorhombic symmetry, and the following parameters were determined: gz = 1.9961, gy = 1.9905, b20 = −558.5, b22 = −351.7, b40 = −0.5, b42 = −56.0, b44 = −40.3, A = 85.5, B = 85.5. The values of bnm, A, and B are in gauss, and the signs are relative. It was possible to relate the axes of the Mn2+ magnetic complexes to the crystallographic axes. Hence, it was determined that the Mn2+ ions replace Mg2+ ions, which are in centers with inversion symmetry, and not Ca2+ ions, which are in centers containing a reflection plane.
A study of the 23Na(n,γ)24Na and 27Al(n,γ)28Al reactions
Authors: Nichol L. W. , Colenbrander A. H. , Kennett T. J.
Published: April 2011

A study of the gamma radiation following thermal-neutron capture by natural sodium and aluminum has been conducted using a Ge(Li) spectrometer. For sodium, 68 gamma rays were observed and their intensities and energies determined; for aluminum, 85 gamma rays were identified. A decay scheme for aluminum has been proposed from the present measurements. The neutron separation energies were found to be 6960.3 ± 1.5 keV for sodium and 7725.5 ± 1.5 keV for aluminum. The lifetime of the 472-keV level in sodium was measured to be 20.5 ± 0.5 ms using a chopped beam of neutrons.
A thought experiment violating Heisenberg's uncertainty principle
Authors: Robinson M. C.
Published: April 2011

In principle, it is possible to make simultaneous and precise measurements of a particle's velocity using two different methods, which should give identical results. It is shown that these results permit the calculation of the particle's position and momentum with a combined error [Formula: see text] at every instant of time in an arbitrarily large interval. It is also shown that, in the special case considered, the statistical interpretation of the wave function is invalid.
Knight shift and the quadrupole interaction in single crystal magnesium
Authors: Dougan P. D. , Sharma S. N. , Williams D. Llewelyn
Published: April 2011

The nuclear magnetic resonance has been studied in single crystal magnesium at 4.2 °K. The measured values for the Knight shift and quadrupolar interaction are K = (0.1127 ± 0.0005)%, K′ = (0.0004 ± 0.0002)%, e2qQ/h = 324 ± 6 kc/s. Comparison with the results of Rowland reveals the Knight shift to be independent of temperature in direct contrast to the behavior of cadmium, but the quadrupole interaction is strongly temperature dependent.
Coulomb excitation of 35Cl projectiles
Authors: Häusser O. , Pelte D. , Alexander T. K. , Evans H. C.
Published: April 2011

Coulomb excitation of the first two excited states in 35Cl was studied by bombarding thick foils of 24Mg and carbon with 35Cl ions of energies between 51 and 61 MeV. De-excitation gamma rays were observed in two 40 cm3 Ge(Li) detectors. From absolute cross-section measurements the following B(E2) values were obtained, B(E2, 0 → 1220) = (0.081 ± 0.009) × 10−50 e2 cm4 and B(E2, 0 → 1762) = (1.17 ± 0.09) × 10−50 e2 cm4. The mixing ratio δ(1762 → 0) was measured to be −2.95 ± 0.45 which can be combined with the corresponding B(E2) value to yield τ(1762) = (0.555 ± 0.050) ps. A Doppler shift attenuation method was employed to interpret the observed gamma-ray lineshapes in terms of nuclear lifetimes. The lineshape analysis yielded τ(1220) = (0.16 ± 0.05) ps and confirmed τ(1762) obtained from the absolute cross-section measurements. The results provide evidence that the three lowest states in 35Cl cannot be interpreted by a weak coupling model.
An inverse scattering technique for electromagnetic bistatic scattering
Authors: Weston V. H. , Boerner W. M.
Published: April 2011

It is shown that the total field produced by a plane wave incident upon a scattering body can be expressed at all points in space as the sum of the incident field and the Fourier transform of a quantity which is related to the scattering matrix. For points exterior to the minimum convex surface enclosing the body, the scattered field is reducible to a plane-wave representation which requires knowledge of the bistatic scattered field, for a fixed frequency and direction of incidence. It is shown that for certain cases, the resulting expression for the bistatic scattered field may be employed in interior portions of the minimum convex shape (including the body) in which case it represents the field arising from a set of equivalent sources. Alternative representations are also given. A technique is presented which yields the surface of a perfectly-conducting piecewise-smooth body from knowledge of the local total field. To achieve uniqueness, the technique must be applied for at least two different frequencies. Numerical results are presented which illustrate the technique.
Lifetime measurements of the six lowest lying levels in 35Cl
Authors: Ingebretsen F. , Alexander T. K. , Häusser O. , Pelte D.
Published: April 2011

The energies, gamma-ray branching ratios, and mean nuclear lifetimes of the six lowest lying levels in 35Cl have been measured. Gamma rays following the reaction 32S(α,pγ)35Cl were studied using two Ge(Li) detectors with 15-cm3 and 40-cm3 active volumes respectively. The lifetimes of the five lowest lying levels were measured using the Doppler shift attenuation method, with the results: 1219 keV, [Formula: see text]; 1763 keV, 0.55 ± 0.15 ps; 2646 keV, 0.30 ± 0.09 ps; 2695 keV, <0.03 ps; and 3003 keV, <0.05 ps. The lifetime of the 3163-keV level was measured to be 60 ± 7 ps, using a recoil distance method. The level structure is discussed taking into account known lifetimes, spins, parities, and gamma-ray mixing ratios.
The dependence of the hyperfine interaction on the cellular potential in Na and K. II
Authors: Moore R. A. , Vosko S. H.
Published: April 2011

The dependence of the Fermi surface electron wave functions in Na and K on (i) an L-dependent effective local cellular potential constructed to simulate Hartree-Fock theory and (ii) the inclusion of the Hartree field due to the conduction electrons in the cellular potential is investigated. All calculations are performed using the Wigner–Seitz spherical cellular approximation and the Schrödinger equation is solved by the Kohn variational method. It is found that to ensure a value of the Fermi surface electron density at the nucleus accurate to ~5%, it is necessary to use the L-dependent potential along with the Hartree field due to a realistic conduction electron density.
Hartree–Fock atomic parameters
Authors: Fraga Serafin , Thorhallsson Jon , Fisk Carolyn
Published: April 2011

A comprehensive calculation of the parameters involved in energy interactions (dipole polarizabilities, magnetic susceptibility, nuclear magnetic shielding, quadrupole coupling constant, magnetic hyperfine structure constant, Fermi contact interaction constant, octopole coupling constant, orbit–orbit interaction, spin–orbit coupling constant, spin–spin coupling constant, and spin–spin contact interaction) in many-electron atoms has been carried out. The corresponding results, together with the values available in the literature, have been compiled in a technical report for the ground states and some excited states of the negative ions, neutral atoms, and the first four positive ions from He to Kr. An example of the prediction of atomic energy levels, using these values, is presented.