bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rectifying Action and the Electromotive Forces of the Films of Ta2O5 and SiO2 at High Temperatures
Authors: Ishikawa Yoshioki , Sasaki Yozo , Seki Yasuo , Inowaki Shûichi 
Published: April 2005

When the anodic films of Ta2O5 or of SiO2, each having the thickness 100∼2500 Å, are heated at high temperatures in contact with MnO2 layers, they exhibit rectifying actions of p-i-n junction type as well as large electromotive forces in the direction of easy flow resulting from the ion flow through the films. The short-circuit ion current increases greatly with increasing temperature, while the open-circuit voltage increases rapidly at first with increasing temperature, reaches a maximum, and then decreases gradually at higher temperatures.
The results obtained are analyzed in the light of a p-i-n junction structure in the film. In the steady states the observed current through the external circuit is equal to the sum of the ion current, the generation, and recombination current, and the leakage current of the junction. Theoretical expressions having an explicit form are given for Iion and If, by making the assumptions that (a) the built-in voltage in the junction is equal to the free-energy change in the reaction of film formation and (b) If is of the Sah-Noyce-Shockley type. Agreement between the theory and experiments is excellent. We believe that the present method of investigation could also be applied in the elucidation of the growth mechanism as well as of the electric properties of films formed on other metals or semiconductors.
Unresolved Fine Structure of the Nitric Oxide γ 0–0 Band for the Determination of Temperature
Authors: Levine David 
Published: April 2005

An experimental program was conducted to investigate the properties of the unresolved rotational fine structure of the NO γ00 band. The experimental values were taken spectroscopically in absorption at controlled temperatures.
An analytic expression representing the unresolved fine structure is utilized to compute absorption coefficients and absorption intensities for the experimental temperatures. A doublet model and a singlet model of the band are investigated.
From the experimental absorption coefficients, temperatures are determined to within 6% of the directly measured values. The rotational constants of the upper and lower states are determined to accuracies of 13 and 6%, respectively, of the known values.
Use of Cataphoresis to Determine Discharge Parameters
Authors: Muller Walter , Tubbs Eldred F. 
Published: April 2005

The balance between diffusion and ion migration in dc discharges in certain mixtures of metal vapors and rare gases produces a very sharp line of demarcation between the region containing only the rare gas and the region containing both the rare gas and metal vapor. Although the formation of such a sharp boundary depends in a complex way upon the elastic and inelastic cross sections for electron-atom collisions, it can be used in a simple way for the determination of certain discharge parameters.
If a cold spot with a well-defined location is provided near the cathode end of the positive column, the distance from the cold spot to the line of demarcation and the potential drop across the tube are, at a given current and rare gas pressure, accurately reproducible functions of the cold-spot temperature. If these functions are determined, and if the neutral-atom diffusion coefficient and positive ion mobility are known for the metal vapor in the rare gas, a simple theory yields values for electron concentration, electron mobility, and the ratio of electron to ion current as a function of pressure of the metal vapor.
Detailed application has been made to a hot-cathode neon-mercury discharge over a range of mercury pressure from 2.5 to 25μ and for a neon pressure of 3 Torr. For a 500-mA discharge n− is about 3.5×1011 cm−3, μ− ranges from 1.4 to 2.5×106 cm2/V sec, and μ−/μ+, from 800 to 1800.
Injection of High Velocity Charged Particles into Strong Magnetic Fields
Authors: MacLeod Malcolm A. , Waniek Ralph W. 
Published: April 2005

Strong magnetic fields are useful in work with high velocity charged particles by virtue of their ability to rotate the particle momentum vector. The degree of usefulness is measured by the extent to which the desired rotations can be produced at the proper positions in the field. It is frequently necessary to inject charged particles into magnetic fields at points remote from these proper positions, in which case the injection parameters which enable the particles to reach these positions must be specified. For the production of gyromagnetic radiation in axially symmetric magnetostatic fields the proper positions correspond to the high field regions near the symmetry axis. The present introductory study is concerned with delineating approximate injection parameter ranges which allow the particles to attain the regions of high magnetic field strength in the field whose axial variation is bell-shaped. The single-particle model is adopted, and the results of both qualitative and quantitative investigations are presented.
A general formulation of the axially symmetric, magnetostatic field, forbidden-zone theory is given and the useful concept of the paraxial forbidden zones is introduced. This theory is then applied to obtain qualitative answers to the injection problem for the bell-shaped field for both zero and nonzero values of the angular momentum constant. Quantitative relations for the zero angular momentum constant case are obtained using the bell-shaped field paraxial trajectories. A discussion of the limitations of the approximations employed is included.
Role of Oxygen in Reducing Silicon Contamination of GaAs during Crystal Growth
Authors: Woods J. F. , Ainslie N. G. 
Published: April 2005

GaAs grown in a horizontal Bridgman crystal growth apparatus to which oxygen has been added exhibits lower silicon content than that grown without oxygen. Material grown under oxygen additions of 10–20 Torr exhibits, at room temperature, carrier densities in the 2–4×1015 cm−3 range and mobilities between 7500–8650 cm2 V−1 sec−1.
Silicon concentrations computed from the reaction 4Ga+SiO2 → 2Ga2O+Si are compared with electrical determinations of donor densities and spectroscopic determinations of silicon concentrations with reasonably good agreement. It is concluded that suppression of SiO2 dissociation at the walls of the silica reaction tube is the most important action of oxygen on GaAs properties although oxygen doping may play a role in the production of high resistivity GaAs.
Ultrasonic Amplification and Non-Ohmic Behavior in CdS and ZnO
Authors: McFee J. H. 
Published: April 2005

This paper presents observations of ultrasonic flux buildup and the accompanying departures from Ohmic behavior in CdS and ZnO (piezoelectric semiconductor) crystals. The results give strong support to a model which connects this non-Ohmic behavior with the amplification of ultrasonic waves.
The behavior of an ultrasonic signal in the presence of varying amounts of ultrasonic flux is also studied experimentally. It is found that the signal gain is substantially reduced by interaction with the flux. The results also lend support to Hutson's theory which ascribes the non-Ohmic behavior of piezoelectric semiconductors to the acoustoelectric current accompanying the ultrasonic flux.
Strain-Enhanced Diffusion in Metals. II. Dislocation and Grain-Boundary Short-Circuiting Models
Authors: Ruoff A. L. , Balluffi R. W. 
Published: April 2005

Rapid diffusion along dislocation cores generally enhances the average bulk diffusion in a dislocated crystal. If each diffusing atom has at least several opportunities to make rapid excursions along various dislocation cores, Hart has shown that DT/DT0 = 1+fDP/DT0. DT is the average bulk diffusivity, DT0 is the diffusivity in the dislocation-free lattice, f is the fraction of atoms in dislocation pipes, and DP is the diffusivity along dislocation pipes. Under these conditions, the diffusion-penetration is increased by the short-circuiting but the general shape of the penetration curve is unaffected. When the dislocations are static, each diffusing atom must visit a number of dislocations, and a necessary condition for the Hart relation to hold is 2(DT0t)½&gt;ld, where t is the diffusion time, and ld is the dislocation spacing. When this condition fails (for example, at lower temperatures), and when the dislocations are static, it is demonstrated that the amount of short-circuiting is greatly reduced and that the dislocations become essentially ``clogged.'' However, if the dislocations move through the crystal, as they do in plastic deformation, the situation is quite different, since in this case the dislocations may visit the diffusing atoms rather than vice versa. In such cases, the short-circuiting may again be randomized and the enhancement can be as large as (but no larger than) the result given by Hart, even if 2(DT0t)½&lt;ld. In certain cases, this type of short-circuiting can produce very large relative enhancements.
A parallel development is given for short-circuiting due to grain boundaries. In particular, it is shown that grain boundary migration and recrystallization, which occurs repeatedly during deformation of metals with low stacking fault energy, can, for temperatures equal to or less than about half the melting temperature, lead to a greatly increased diffusion coefficient without altering the general shape of the penetration curve.
A number of the results established in this work (Part II) are used in Part III (to be published) where a comprehensive interpretation of recent experimental work in the field is carried out. Part I consists of an analysis of point defect models for strain-enhanced diffusion.
Analysis of Noise from Magnetic Storage Media
Authors: Stein Irving 
Published: April 2005

Noise arising from the transduction of a storage medium, such as a magnetic tape, is analyzed for the case where the storage elements (magnetic domains) are noninteracting and the magnetic tape, except where otherwise specified, is homogeneous. Since the fields arising from the tape are uniquely determined only if the boundary conditions (established by the presence of the reproduce head) are given, the broadband signal-to-noise ratio is a function not of the tape alone but of the tape-head system. It is found that the signal-to-noise ratio is proportional to the square root of the ``effective'' number of particles detected by the head. Thus, the signal-to-noise ratio is proportional to the square root of a length of tape, which is a measure of the tape-head resolution. The noise itself can be considered to arise from sources which add, in circuit terminology, serieswise across the width and along the length of the tape.
The essential source of what we call the ``no-signal'' tape noise is not in the surface roughness (assuming an otherwise homogeneous tape) or the physical distribution of the particles, but in the random orientation of the magnetic moments. Furthermore, a distribution in either the particle magnetization or the particle volume increases the noise. These conclusions are derived from purely statistical considerations.
Although the basic concepts of tape-head noise can be established without considering interaction of the tape particles, the formulas for dc and ac signal-to-noise and accurate quantitative results for the no-signal noise can only be obtained if the effect of particle interaction is included in the analysis. An externally applied field divides the particles into two groups: ``unflipped'' particles, which strongly interact, and ``flipped'' particles, which weakly interact. Using this distinction, it is possible to derive the signal-to-noise ratio for dc- and ac-magnetized tapes with no further reference to particle interaction. The formula for signal-to-dc noise is found; for small magnetizations it is seen that the noise voltage is proportional to the square root of the magnetization level. Alternating current noise is found to be purely a modulation of dc noise. Obtaining quantitative results, of course, involves interaction theory, a subject not treated here.
Ripple Hysteresis in Thin Magnetic Films
Authors: Feldtkeller Ernst 
Published: April 2005

Hysteresis measurements and electron micrographs have shown that the rotation in films with uniaxial anisotropy in low fields is not reversible, in contradiction to the single domain theory. A film with Hc/HK=2.3, for instance, has a remanence of 0.04 Ms in an alternating field of the amplitude Ĥ=0.4 HK parallel to the hard axis. The remanence depends on Hc/HK, on the dispersion of the anisotropy, and on the amplitude and the direction of the applied field.
This irreversibility is caused by the magnetization ripple. If the magnetization is rotated, the ripple small-angle walls rearrange themselves by wall motion normal to the new magnetization direction. This wall motion requires a certain excess of energy which results in hysteretic losses even if the applied field strength is lower than the Stoner-Wohlfarth critical field for irreversible rotations.
Preparation, Phase-Boundary Energies, and Thermoelectric Properties of InSb-Sb Eutectic Alloys with Ordered Microstructures
Authors: Liebmann W. K. , Miller E. A. 
Published: April 2005

Two-phase solids, single-crystal rods of Sb in a matrix of single-crystal InSb, have been prepared by eutectic crystallization. The size of the Sb rods decreases with increasing crystallization velocity, in quantitative agreement with the theory of eutectic crystallization.
The boundary energy between the InSb and the Sb phases was determined both from the parameters of the crystallization and from a dislocation model. Both values agree, indicating that the strain energy of the dislocations at the phase boundary is the chief contributor to the interfacial energy.
The electrical resistivity ρ, the thermoelectric power Q, and the thermal conductivity K have been measured as a function of the structural arrangement of the two phases in the alloys. The magnitudes of ρ and Q have been explained by simple electrical analogs of the eutectic structure.
A characteristic decrease of the thermal conductivity of the eutectic alloys has been observed. The reduction in K is probably caused by interaction of phonons with the phase boundaries.
Photoelectric and Thermionic Schottky Deviations for Tungsten Single Crystals
Authors: Stafford D. F. , Weber A. H. 
Published: April 2005

The periodic Schottky deviations have been obtained for photoelectric and thermionic emission in the [111] direction from a tungsten single crystal in a dual experiment. The thermionic deviations, compared with well-established experimental results and theory, serve as a check on the photoelectric work. The photoelectric deviations, not previously established experimentally in detail, are compared with theory. A composite theory, using Cutler-Gibbons thermionic parameters in Juenker's photoelectric analysis, is in best agreement with the experimental photoelectric results.
The photoelectric deviations are in fair agreement in period and phase with the thermionic deviations, the agreement being better at the larger applied electric fields (corresponding to the earlier time of a run) than at the smaller field values. The photoelectric deviation amplitude is 1.7% at E½=350 (V/cm)½.
Collisions of Metastable Atoms
Authors: Hasted J. B. 
Published: April 2005

Collision experiments with He 23S and Ne 3P metastable atoms are described, giving the total collision cross sections of these atoms with He, Ne, A at thermal energies, also the absorption cross sections of resonance photons from the He, Ne discharges.
The secondary electron yields from He metastable atoms and from resonance photons incident upon W, Mo, Pt surfaces flashed to 1700°C are compared with the yields from an unflashed Au surface, previously determined absolutely. The rate of rise of yield due to gas contamination is examined. The yields from the flashed surfaces are found to be distinctly smaller than Hagstrum's yields for low-energy positive ions.
Factors Affecting Separations of Suspensions in Nonuniform Electric Fields
Authors: Pohl H. A. , Schwar J. P. 
Published: April 2005

A study of the more quantitative aspects of the behavior of suspended polymer particles in a real dielectric is presented. While it is recognized that nonuniform fields exert an attractive force of appreciable magnitude upon particles of high dielectric constant suspended in a liquid medium of lower dielectric constant, the limits of such behavior are not precisely known. This report presents some quantitative data on the subject. The results show that in real dielectrics there is an appreciable effect due to the very small currents, about 1013 amperes at applied voltages in the kilovolt range [R. Coelho, Progress Report No. 22, pp. 13–17, Laboratory for Insulation Research, Massachusetts Institute of Technology (December, 1957)] which even a good liquid insulator supports.
It is shown that the initial attraction to the central electrode due to the nonuniform field and its polarizing induction is gradually overcome by the repulsive effects of charge accumulated on the particles resulting from ionic conduction and related events in the liquid. The experimental observations include the study of the effects of field strength, electrode size, cell size, and particle size. Field strength, electrode size, and particle size show criticality. At certain upper limiting voltages, smaller central electrode diameters and small particle sizes, all precipitation appears to be prohibited. Use of the newly discovered ``sluff-off'' voltage for making particle size separations is discussed.
Effect of Spin on Natural Convection in Mercury Heated from Below
Authors: Dropkin David , Globe Samuel 
Published: April 2005

In the absence of spin, natural convection between two horizontal surfaces in mercury heated from below is found to be given by the formula N=0.051R⅓ where N is the Nusselt number and R the Rayleigh number. Spinning the mercury about a vertical axis reduces the amount of convection after a certain value of the spin (Taylor number) is exceeded. This value of the Taylor number increases with increasing heat flux.
Turbulent fluctuation of the temperatures of the bounding surfaces are observed and under some circumstances periodic oscillations of the temperature of the bounding surface are also noted.
Improved Semiautomatic Histogram Plotter
Authors: Kelsey R. H. , Hanson E. E. 
Published: April 2005

An improved instrument for constructing particle size distribution diagrams from electron micrographs is described. Its use permits the measurement of large numbers of particles rapidly, and with low observer fatigue. The magnification of the image to be measured may be chosen to make the instrument error less than the resolution of the electron microscope.
The device consists of a measuring unit in the form of a pair of dividers, controlling a servo system which automatically classifies the particles and plots the histogram as an array of steel balls in a slotted matrix.
Adjustments for zero and span are provided, and the total number of particles measured is recorded.
Experimental Determination of Atomic Scattering Factors
Authors: Roof R. B. 
Published: April 2005

The atomic scattering factor for aluminum has been experimentally re-examined. First-order corrections for the effect of temperature, surface roughness, primary extinction, secondary extinction, and anomalous dispersion were applied to experimental absolute intensity measurements made on a powder slab of aluminum.
The average deviation between the experimentally determined and the theoretical atomic scattering factor for aluminum is 0.16 electron. The slightly different shape of the experimental curve, as compared to the theoretical curve, is interpreted as evidence for a greater contraction in the 3p shell of aluminum than had been heretofore assumed.
Infrared Studies of Birefringence in Silicon
Authors: Lederhandler S. R. 
Published: April 2005

Permanent and elastic strains in silicon crystals grown by the Czochralski technique have been studied by observing the crystal birefringence. These studies reveal that the presence of birefringence is related to (a) plastic deformation caused by severe thermal gradients which produce forces exceeding the crystal yield force and (b) work damage or externally applied forces. The first source of birefringence has been termed permanent strain since this appears in the crystal as grown and the birefringence pattern cannot be altered by changes in sample geometry. This characteristic is typical of a ``frozen-in'' strain. A strain-free sample may also be made birefringent, however, by a work damage such as surface abrasion or sand blasting. Such a birefringent pattern can be altered if the sample geometry is changed. This characteristic, of course, is typical of elastic strain.
Studies made of samples both parallel and perpendicular to the direction of crystal growth revealed birefringence patterns similar to those of naturally anisotropic crystals such as calcite. The patterns indicate the formation of a pseudo-optic axis in silicon coincident with the growth direction and is caused by the uneven temperature distribution which results in perdominantly uniaxial stress.
Regions of tension and compression have been discovered and their respective magnitudes determined. The calculation of the ``frozen-in'' tension and compression stresses are based upon experimental determination of the stress-optic coefficient of silicon. Satisfactory agreement was obtained between frozen-in stress calculations and measurements of yield stress at elevated temperatures.
Measurement of the Linear Magnetostriction of Hard-Worked Nickel
Authors: Stauss H. E. 
Published: April 2005

The influence of plastic deformation upon the linear magnetostriction of hard-worked nickel has been determined by use of direct measurements of strain in three normal directions and then by measurement of magnetostriction in the same three directions using the method of rotating the specimen 90° for each measurement. This combination of measurements appears to have advantages for the interpretation of magnetostriction in nonisotropic bodies.
The value of magnetostriction at saturation for grade A nickel plastically deformed with an 84% reduction of cross-sectional area was found to be −33.5±1×10−6. This compares with −35±1×10−6 for annealed nickel of the same quality. The hard-worked nickel was free of volume magnetostriction of determinable magnitude. It showed inappreciable preferred domain orientation. It did appear to have a small amount of preferred crystalline orientation.