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1 Sep 1959

Volume 30, Issue 9, pp. 1323-1472

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Editorial

J. Appl. Phys. 30, 1323 (1959); http://dx.doi.org/10.1063/1.1735330 (1 page) | Cited 3 times

Online Publication Date: 16 June 2004

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Neutron Diffraction Techniques and Their Applications to Some Problems in Physics

S. S. Sidhu, LeRoy Heaton, and M. H. Mueller

J. Appl. Phys. 30, 1323 (1959); http://dx.doi.org/10.1063/1.1735331 (18 pages) | Cited 12 times

Online Publication Date: 16 June 2004

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Neutron transmission and diffraction techniques are described with application to problems in nuclear physics, crystallography, magnetic scattering, physical structure of materials, and the liquid state. Experimental results for nuclear scattering amplitudes, positions of light atoms among heavy atoms, magnetic moment alignments in antiferromagnetic structures, and diffraction of neutrons by alkali metals in the liquid state are reported. The main features of the design and operation of the neutron diffraction spectrometer and the auxiliary equipment are given.
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Use of the Principles of Conservation of Energy and Momentum in Connection with the Operation of Wave‐Type Parametric Amplifiers

J. R. Pierce

J. Appl. Phys. 30, 1341 (1959); http://dx.doi.org/10.1063/1.1735332 (6 pages) | Cited 4 times

Online Publication Date: 16 June 2004

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The operation of a wave‐type parametric amplifier may be thought of in terms of the force exerted by traveling discontinuities or reflecting elements on the waves present in the device. By invoking the principles of conservation of energy and momentum it is possible to understand in very simple terms certain limitations on the operation of such devices and to arrive very easily at certain general relations governing their behavior, including the Manley‐Rowe relation. It is proposed that for a guided wave the momentum per unit distance is the power divided by the product of the group and phase velocities.

Harmonic Current Growth in Velocity‐Modulated Electron Beams

T. G. Mihran

J. Appl. Phys. 30, 1346 (1959); http://dx.doi.org/10.1063/1.1735333 (5 pages) | Cited 2 times

Online Publication Date: 16 June 2004

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Harmonic currents accompanying a fundamental space charge wave of current in a velocity modulated electron beam are found to grow with distance even though the peak amplitude of the fundamental current remains relatively constant.
This effect was first noted in studying the results of a series of disk‐electron calculations. Subsequently, second harmonic growth was found experimentally using a sliding cavity setup. A physical explanation of this phenomenon is given.
The harmonic growth can be interpreted as parametric amplification in which the finite electron beam acts as the nonlinear element, with the fundamental current providing the pump power.

Measurement of Thermal Conductivity by Utilization of the Peltier Effect

T. C. Harman, J. H. Cahn, and M. J. Logan

J. Appl. Phys. 30, 1351 (1959); http://dx.doi.org/10.1063/1.1735334 (9 pages) | Cited 80 times

Online Publication Date: 16 June 2004

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A special technique for the accurate measurement of thermal conductivity is discussed. The method involves use of the Peltier heat to maintain a temperature gradient along the specimen. Straightforward measurements allow calculation of the absolute value of the thermoelectric power, thermal conductivity, and electrical resistivity. An especially useful feature of the method is that the thermoelectric figure of merit is given in terms of the ratio of two voltages. The theory is presented for the case in which the radiative heat transfer is important. The method has been tested experimentally at 300°K only, but analysis suggests that accurate measurements of thermal conductivity can be made by this technique on low thermal conductivity materials of small dimensions up to 1000°K.

Texture of Evaporated NiFe Thin Films

R. R. Verderber

J. Appl. Phys. 30, 1359 (1959); http://dx.doi.org/10.1063/1.1735335 (5 pages) | Cited 7 times

Online Publication Date: 16 June 2004

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The texture of 28 evaporated NiFe thin films, of various compositions, were determined by the Geiger counter x‐ray reflection technique. The grain orientation of the thin films is described by one of the following three textures; random, [111] fiber axis, or a [311] fiber axis. The development of a texture was influenced by the temperature of the substrate during deposition. The coercive force and the selectivity, which is a measure of the slope of the sides of the hysteresis loop, of the films were measured on a 60‐cycle hysteresis loop tracer. Only the selectivity was found to be related to the texture of the films. Films with a [311] fiber axis had a selectivity less than 0.5, while films with a [111] fiber axis had a selectivity of 0.5 or greater.

High‐Temperature Oxidation of Iron Whiskers

J. V. Laukonis and R. V. Coleman

J. Appl. Phys. 30, 1364 (1959); http://dx.doi.org/10.1063/1.1735336 (5 pages) | Cited 5 times

Online Publication Date: 16 June 2004

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Single crystal α‐iron whiskers have been used to study early stages in the oxidation of iron at high temperatures. Well defined oxide patterns are observed on clean iron surfaces and there are characteristic differences between the patterns on {100} and {110} faces. These differences tend to be eliminated if a natural oxide film is present before the high temperature oxidation is performed. Unusual mosaic oxide patterns which form on clean {100} iron surfaces are shown.

Uniform Rotational Flux Reversal of Ferrite Toroids

E. M. Gyorgy and F. B. Hagedorn

J. Appl. Phys. 30, 1368 (1959); http://dx.doi.org/10.1063/1.1735337 (8 pages) | Cited 13 times

Online Publication Date: 16 June 2004

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A model is presented for the high speed uniform rotational flux reversal of ferrite toroids. The magnetization is uniform in the sense that the components of magnetization in a cylindrical coordinate system are independent of position. Analysis of the model, to a very good approximation, leads to results identical with those obtained from uniform rotation in isotropic thin films. The minimum switching coefficient predicted by this model is 0.005 oe μsec. Experimental confirmation of a high speed switching mode in ferrite toroids is given. A toroid with a wire loop embedded in it was used to induce the proposed flux configuration. The switching coefficient and the extrapolated threshold field associated with the high speed mode have been found to decrease with increasing temperature.

Some Criteria for the In Situ Combustion of Crude Oil

P. Cooperman

J. Appl. Phys. 30, 1376 (1959); http://dx.doi.org/10.1063/1.1735338 (5 pages) | Cited 5 times

Online Publication Date: 16 June 2004

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This paper presents a steady‐state theory for the in situ combustion of oil in an underground reservoir. The hydrodynamic, chemical, and thermal aspects are treated in their relation with each other. The major results are three criteria for successful forward burning. These criteria state the minimum values for the oil saturation, the carbon‐hydrogen ratio, and the volume flow rate.

Relationship between Signal‐to‐Noise Ratio and Threshold of Response of Infrared Photoconductors Limited by Generation‐Recombination Noise

W. E. Spicer

J. Appl. Phys. 30, 1381 (1959); http://dx.doi.org/10.1063/1.1735339 (4 pages)

Online Publication Date: 16 June 2004

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For photoconductors in which the dominant noise is generation‐recombination noise, it is shown that the signal‐to‐noise ratio is proportional to expβEi/2kTD, where Ei is the threshold response of the photoconductor, TD is its temperature, and β is a constant between unity and one‐half. If longer wavelength response is desired (smaller Ei) without sacrificing signal‐to‐noise ratio, this can only be achieved by lowering TD. Similarly, for any given Ei, the generation‐recombination noise can be reduced to an arbitrarily low level by lowering TD sufficiently. Expressions are obtained for the optimum value of Ei under typical operating conditions.

Microwave Conductivity of Slightly Ionized Air

Henry Margenau and Dorothea Stillinger

J. Appl. Phys. 30, 1385 (1959); http://dx.doi.org/10.1063/1.1735340 (3 pages) | Cited 3 times

Online Publication Date: 16 June 2004

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The conductivity of air ionized by injection of electrons at different altitudes is computed with the use of experimentally established collision cross sections of electrons in oxygen and nitrogen. The results, in the form of graphs, are compared with the usual, simpler formulas based upon the assumptions of (a) a constant collision frequency and (b) a constant mean free path. The departures are in excess of the experimental error in good conductivity measurements.

Correlated Collisions in a Displacement Spike

G. Leibfried

J. Appl. Phys. 30, 1388 (1959); http://dx.doi.org/10.1063/1.1735341 (9 pages) | Cited 49 times

Online Publication Date: 16 June 2004

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The influence of correlated collisions due to lattice structure is investigated for f.c.c. lattices and discussed in detail for Cu. The model used is that of Silsbee in which the assumed exponential potential between atoms gives approximately hard core collisions. Two possibilities which may cause long‐range effects are investigated; (1) focusing collisions which are suggested not to effect an interstitial transport. (2) crowdion‐like collisions with interstitial transport. The number of such collisions as well as their range is calculated for given energy of a primary knock on. The result shows that the range should be determined by the focusing collisions only. The theoretical range (about 100 atom spacings) is in agreement with the experimental value derived out of the damping experiments in Cu. The effect of crowdion collisions on disordering is discussed for Cu3Au.

Elastic and Plastic Behavior in the Impact of Cylinders against Plates

Marvin E. Backman

J. Appl. Phys. 30, 1397 (1959); http://dx.doi.org/10.1063/1.1735342 (7 pages) | Cited 2 times

Online Publication Date: 16 June 2004

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A theory of the indentation of a thick plate from impact by a flat‐ended elastic cylinder is derived from elastic and plastic theories and compared to experimental values for 2024‐T4 aluminum alloy, half‐hard‐naval brass and Armco iron. Plastic conditions in plates of the aluminum alloy are considered in detail by assuming an exponential increase in hardness to a maximum value. These results are sensitive to projectile length and are compared to experimental results for five projectile lengths.

Pulse Technique for Probe Measurements in Gas Discharges

John F. Waymouth

J. Appl. Phys. 30, 1404 (1959); http://dx.doi.org/10.1063/1.1735343 (9 pages) | Cited 64 times

Online Publication Date: 16 June 2004

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A pulse technique for making Langmuir probe measurements in gas discharges has been developed. The basic procedure consists in operating the probe 40–50 v negative with respect to the discharge, and pulsing it positive at a repetition rate of 60 cps. The probe current‐voltage characteristic during the positive‐going pulse is presented on an oscilloscope and the resulting trace is photographed. The phase of the pulse may be varied, so that the method is useful for studying 60 cps ac discharges as well as dc discharges. Positive‐ion bombardment while the probe is strongly negative tends to sputter away contamination and make it possible to keep the probe clean while making measurements within one mm of an oxide cathode at 1000°C, despite rapid evolution of contaminants from the cathode. Together with the small size of the probes that can be used, this permits meaningful measurements to be made in the negative glow of an oxide‐cathode low‐pressure discharge of the fluorescent‐lamp type. Measurements on such lamps are described which demonstrate the presence of energetic primary electrons from the cathode as well as secondary electrons in the negative glow.

Anomalous Electrical Properties of p‐Type Indium Arsenide

Jack R. Dixon

J. Appl. Phys. 30, 1412 (1959); http://dx.doi.org/10.1063/1.1735344 (5 pages) | Cited 15 times

Online Publication Date: 16 June 2004

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Hall constants and resistivities have been measured as a function of carrier concentration for zinc‐doped, single crystal p‐type indium arsenide at temperatures ranging from 4.2 to 500°K. For carrier concentrations greater than 2×1017 cm−3 the electrical properties appear to be normal for a material of this type. However, for smaller carrier concentrations anomalies appear which consist of dips and double reversals in the Hall constant‐temperature relationship. These results are in agreement with data reported by Folberth and Weiss for polycrystalline material. A mechanism involving inhomogeneities arising from the inclusion of microscopic n‐type regions in p‐type material is proposed to explain the anomalies. Such small n‐type regions could arise from the aggregation of impurities about dislocations. On the basis of this model, it is predicted that the anomalies should be removed by appropriate heat treatment of the material. The prediction is confirmed by experiment. Recent work of Rupprecht suggests that the anomalous behavior of p‐type InAs is due to an n‐type surface layer which can be introduced by grinding or polishing, and removed by etching. This is consistent with the mechanism we propose.

Effective Antenna Temperatures Due to Oxygen and Water Vapor in the Atmosphere

D. C. Hogg

J. Appl. Phys. 30, 1417 (1959); http://dx.doi.org/10.1063/1.1735345 (3 pages) | Cited 16 times

Online Publication Date: 16 June 2004

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Calculations of the effective noise temperature at the terminals of a high gain antenna due to oxygen and water vapor in the atmosphere are given for the frequency range 0.5 to 40 kmc. In the 1 to 10 kmc band, the effective temperature increases from about 3° to 100°K as the zenith angle is increased from 0° to 90°. Calculated values of the total attenuation through the atmosphere are given.

Diffusion of Aluminum, Magnesium, Silicon, and Zirconium in Nickel

Herbert W. Allison and Harold Samelson

J. Appl. Phys. 30, 1419 (1959); http://dx.doi.org/10.1063/1.1735346 (6 pages) | Cited 17 times

Online Publication Date: 16 June 2004

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The diffusion rates of aluminum, magnesium, silicon, and zirconium, alloyed as single additives in nickel, have been measured at temperatures between 800°C and 970°C. The method consisted of measuring the weight gain caused by surface oxidation of the additive in a wet hydrogen ambient. The surface oxides were identified by electron diffraction. Grain size was about 0.05 mm in Al☒Ni, Si☒Ni, and Mg☒Ni but less than 10−3 mm in Zr☒Ni. The composite volume and grain boundary diffusion coefficients are given by DAi→Ni = 1.1 exp(−59 500∕RT); DMg→Ni = 2.3×10−5 exp(−31 300∕RT); DZi→Ni = 10.6 exp(−64 800∕RT); DZr→Ni = 1×10−5 exp(−26 700∕RT). Stereo and photomicrographs indicate considerable grain boundary diffusion, particularly in Mg☒Ni and Zr☒Ni.

Nuclear Magnetic Resonance Studies of Dislocations in NaI and KI

J. F. Hon and P. J. Bray

J. Appl. Phys. 30, 1425 (1959); http://dx.doi.org/10.1063/1.1735347 (4 pages) | Cited 9 times

Online Publication Date: 16 June 2004

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Intensity anomalies have been found in the nuclear magnetic resonance of I127 in NaI and KI single crystals when the magnetic field is along a [1,0,0] type direction. The intensity enhancement in these cases indicates a collapse of the satellite transitions (m → m − 1, m ≠ ☒) into the central transition (m = ☒ → m = −☒). It is concluded that the crystals contain edge and∕or screw dislocations which are preferentially oriented along [1,1,0] and [1,0,0] type directions, respectively. The degree of orientation is greater in NaI than in KI.
These studies afford an explanation of anomalous resonance line widths reported for NaI by other observers.

New Method for Range Measurements of Low‐Energy Electrons in Solids

J. E. Holliday and E. J. Sternglass

J. Appl. Phys. 30, 1428 (1959); http://dx.doi.org/10.1063/1.1735348 (4 pages) | Cited 47 times

Online Publication Date: 16 June 2004

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A new method for determining the range of low‐energy electrons in solids is described and compared with older techniques. In the new method, the material under study is deposited on a thick layer of greatly different electron backscattering characteristics. When the incident electrons have just sufficient energy to penetrate to the support and return to the surface, a marked change in the backscattered fraction occurs. In this manner, the need for very thin organic supporting films of unknown stopping power is avoided. Range‐energy data from 1 to 15 kev for films of aluminum on a gold substrate obtained by this technique are found to agree with the data obtained by the use of cathode luminescence to detect electron penetration. The technique was applied to thin films of gold in the energy region from 2 to 15 kev. It was found that the practical ranges in mg∕cm2 for gold and aluminum were the same below 10 kev, unlike the situation in the mev region where the effective penetration into Al is about twice that for Au due to the importance of nuclear scattering in a high Z element. Good agreement is found with the Bohr‐Bethe theory for aluminum at all energies and for Au below ∼10 kev.

Initial Wedge Impact on a Compressible Fluid

S. F. Borg

J. Appl. Phys. 30, 1432 (1959); http://dx.doi.org/10.1063/1.1735349 (5 pages) | Cited 1 time

Online Publication Date: 16 June 2004

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A physical model is developed and a solution is obtained for rigid two‐dimensional wedge impact on a compressible fluid. The solution is given as a combined compressible flow—elastic viscous body action. The combined solution satisfies the field equations for the physical model assumed for the impact and, approximately, the necessary boundary conditions. It holds for a semicircular wedge, expanding similar to itself with time and entering the fluid at a velocity equal to half the velocity of sound. Hence, it applies best to wedges with pointed noses. Approximate procedures are given for solving noncircular shapes moving with arbitrary velocities. An order‐of‐magnitude estimate is made for the time of importance of compressibility effects.

Some Effects of Fast Neutron Irradiation on Carrier Lifetimes in Silicon

R. W. Beck, E. Paskell, and C. S. Peet

J. Appl. Phys. 30, 1437 (1959); http://dx.doi.org/10.1063/1.1735350 (3 pages) | Cited 1 time

Online Publication Date: 16 June 2004

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Single crystal specimens of silicon have been exposed to fast neutrons from a reactor source to determine the room temperature effects of irradiation on carrier lifetimes. For highly n‐ and p‐type material the approximate lifetime damage constants, defined as 1/τ = 1/τi+αϕ, are found to be αn=4.4×10−7 (nvt)−1 × (sec)−1 and αp=1.2×10−6 (nvt)−1 (sec)−1. Two possible positions of the dominant recombination level are 0.36 ev below the conduction band or 0.33 ev above the valence band. Further agreement with the value of αp has been obtained by measuring high level lifetime in silicon junction diodes.

Thermoelectric Properties of the Plasma Diode

H. W. Lewis and J. R. Reitz

J. Appl. Phys. 30, 1439 (1959); http://dx.doi.org/10.1063/1.1735351 (7 pages) | Cited 16 times

Online Publication Date: 16 June 2004

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The thermoelectric properties of a gas‐filled diode containing a high density of positive ions are discussed in some detail. The complete circuit of diode and load is treated as a thermocouple, and expressions for both the Seebeck emf and thermoelectric conversion efficiency are obtained as a function of cathode and anode temperatures. The interior of the diode is divided, for convenience, into three regions: (1) the cathode sheath, (2) main body of plasma, and (3) the anode sheath. The anode sheath is the region of large temperature gradient; the approximate temperature distribution in the sheath is obtained by solving a greatly simplified heat‐conduction equation. Finally, the results of this analysis are compared with experiments performed by Grover, Roehling, Salmi, and Pidd.

Effect of Pressure on the Spectra of Olivine and Garnet

A. S. Balchan and H. G. Drickamer

J. Appl. Phys. 30, 1446 (1959); http://dx.doi.org/10.1063/1.1735352 (2 pages) | Cited 13 times

Online Publication Date: 16 June 2004

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The effect of pressure has been measured on the absorption edge of olivine and on the Fe++ peak of garnet to over 150 000 atmos. The absorption edge of olivine shifts red by about 9% of the gap in this pressure range. The Fe++ peak in garnet shifts to higher energies by 700 cm−1 in 170 000 atmos, due to increased splitting of the d levels by the ligand field. This is consistent with previous experimental work on transition metals, and with available theory. The temperature coefficient of the absorption edge of olivine was also measured at atmospheric pressure to 327°C. It exhibited a linear red shift of 4.21×10−4 ev∕°C over this range.
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Effect of Substrate Crystalline Perfection on Epitaxial Growth

A. K. Chatterji

J. Appl. Phys. 30, 1448 (1959); http://dx.doi.org/10.1063/1.1735353 (2 pages)

Online Publication Date: 16 June 2004

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Noise Figure of Reactance Converters and Parametric Amplifiers

A. Van Der Ziel

J. Appl. Phys. 30, 1449 (1959); http://dx.doi.org/10.1063/1.1735354 (1 page) | Cited 1 time

Online Publication Date: 16 June 2004

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