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Showing papers in "International Journal of Electronics in 1961"


Journal ArticleDOI
TL;DR: In this paper, the control problem of a non-linear, time varying plant which is disturbed by, or must follow, some stochastic process is considered, and the system of plant plus inputs must be adequate.
Abstract: The control problem considered is that of a non-linear, time varying plant which is disturbed by, or must follow, some stochastic process. Further, the system of plant plus inputs must be adequatel...

116 citations


Journal ArticleDOI
TL;DR: It has been reported by various experimenters (Collins et al. as discussed by the authors, Sorokin and Stevenson 1060) that the light output from optical masers sometimes consists of a series of intense short spikes.
Abstract: It has been reported by various experimenters (Collins et al. 1060, Sorokin and Stevenson 1060) that the light output from optical masers sometimes consists of a series of intense short spikes. Thi...

85 citations


Journal ArticleDOI
TL;DR: In this article, the coercive force of thin films is interpreted quantitatively on the basis of the theory of thermal fluctuation effects, and values of the anisotropy field and mean effective crystallite size are deduced and discussed.
Abstract: The observation (Hollenthal 1960) that the coercive force of thin films is time dependent is interpreted quantitatively on the basis of the theory of thermal fluctuation effects, and values of the anisotropy field and mean effective crystallite size are deduced and discussed.

29 citations


Journal ArticleDOI
TL;DR: A new determination involving gravity segregation showed the silicon content of the eutectic to be 3 15±0 05 weight % or 18 6±0 3 atomic %.
Abstract: A new determination involving gravity segregation shows the silicon content of the eutectic to be 3 15±0 05 weight % or 18 6±0 3 atomic %.

21 citations


Journal ArticleDOI
TL;DR: In this paper, a technique for the measurement of reignition voltage characteristics of spark gaps after the passage of a high current discharge is described, and the initial discharge current is varied from 100 to 235 kA, and recovery-measurements in air at atmospheric pressure are given for 6 4 and 16 mm diameter tungsten electrodes and for 16, 19 and 76 mm diameter copper electrodes.
Abstract: This paper describes a technique for the measurement of reignition voltage characteristics of spark gaps after the passage of a high current discharge. The initial discharge current is varied from 100 to 235 kA, and recovery-measurements in air at atmospheric pressure are given for 6 4 and 16 mm diameter tungsten electrodes and for 16, 19 and 76 mm diameter copper electrodes. The effects of gap length, current amplitude and electrode size and material are discussed, and it is observed that electrode size has a powerful influence upon the recovery process Gas temperatures are derived on the assumption that Paschen's law holds during the final recovery period.

17 citations


Journal ArticleDOI
TL;DR: In this paper, measurements of attachment coeflficionte made with a Bradbury electron filter in oxygen for X/p varying between 4 and 30 volts/em/mm Hg were obtained.
Abstract: Measurements of attachment coeflficionte made with a Bradbury electron filter in oxygen for X/p varying between 4 and 30 volts/em/mm Hg show good agreement with recent data obtained with other techniques. Data on three-body coefficients were also obtained.

13 citations


Journal ArticleDOI
TL;DR: In this article, a solution in closed form for Brillouin flow under relativistic conditions in a cylindrical geometry is derived in the limit of low beam temperature, where curves and formulae are given relating density, magnetic field, energy and tangential velocity throughout the beam.
Abstract: A solution in closed form for Brillouin flow under relativistic conditions in a cylindrical geometry is derived in the limit of low beam temperature. Curves and formulae are given relating density, magnetic field, energy and tangential velocity throughout the beam. In particular it is found that the forward velocity is constant to all orders in the radial coordinate, that under ultra-relativistic conditions the beam of maximum perveance has a forward velocity approaching c/√2, and that the maximum current is proportional in the ultra-relativistic limit to the square of the energy of the outermost particles.

13 citations


Journal ArticleDOI
TL;DR: An extremum control system is considered in which the output from a plant is minimized by adjusting inputs to the plant in discrete steps of constant size, and results for vanishing step size in the two-estimate system are derived.
Abstract: An extremum control system is considered in which the output from a plant is minimized by adjusting inputs to the plant in discrete steps of constant size. The direction of stepping is determined by estimates of the true output in the presence of Gaussian noise. The criterion of steady-state performance is the average deviation of the true output from the minimum. Performance of a system with single-input plant is computed when one estimate of output is made after each step; the analysis is supported by experimental results. Analysis is simpler when two independent estimates are made per step; performances of the two types of system are compared. Limiting results for vanishing step size in the two-estimate system are derived for a single-input plant with both output noise and input disturbance, and for a multi-input plant with output noise only.

12 citations


Journal ArticleDOI
TL;DR: Problem arising in the application of techniques of automatic control to complex non-linear systems subject to random disturbances may be solved by automatic optimization, and a variety of such schemes have been proposed.
Abstract: Problems arising in the application of techniques of automatic control to complex non-linear systems subject to random disturbances may be solved by automatic optimization. A variety of such schemes have been proposed. These are discussed with reference to a performance criterion which is to be optimized; they may be classified as employing either open-loop or closed-loop methods of optimization. A terminology is suggested for the description of such systems.

10 citations



Journal ArticleDOI
TL;DR: In this article, an almost instantaneous photo-variation of the discharge current was studied in various types of discharge vessels, charged with air, H2 and I2 vapour, and excited by fields due to continuous and alternating potentials (V).
Abstract: Joshi effect (±δi) an almost instantaneous and reversible photo-variation of the discharge current (i), is studied in various types of discharge vessels, charged with air, H2 and I2 vapour, and excited by fields due to continuous and alternating potentials (V). t was observed by a counter-sealer, and/or a galvanometer after rectification. +δi was observed under β-rays from a 50 millicurie Ra-Be source, and various frequency bands of the visible. The intensity (I) was varied over 30 times using the former, and 500 times with the latter. A 100% negative effect is observed near and above the threshold Vm; it decreases with increase of V. ± δi (disfavoured by a prolonged discharge) occurs within a restricted range of conditions, viz. low J and V. As these are increased, a sharp inversion equation follows which is fully reversible in respect of I and V. The minimum inversion intensity and the inversion potential vary in the order: violet < blue < green < yellow < red and, I2 H2 < air. ±δi is independe...

Journal ArticleDOI
TL;DR: For the double diffused transistor, Poisson's equation is solved in one dimension; this solution is used to determine depletion layer properties of its collector and emitter junctions as discussed by the authors.
Abstract: For the double diffused transistor, Poisson's equation is solved in one dimension; this solution is used to determine depletion layer properties of its collector and emitter junctions. Assuming an impurity atom distribution characterized by the summation of complementary error functions, depletion layer widths are established far the equilibrium emitter junction and for the reverse biased collector junction. Applications of this analysis are presented throughout a wide range of physical and geometrical parameters; graphical illustrations are given for the electrical base width, the collector ‘ punch-through ’ voltage, and others.

Journal ArticleDOI
TL;DR: In this article, a rigorous analytic solution for the bunching of an in finite electron beam modulated by an infinitesimal gap is derived as long as no overtaking occurs.
Abstract: A rigorous analytic solution has been derived for the bunching of an in finite electron beam modulated by an infinitesimal gap. The solution is valid as long as no overtaking occurs. The amplitude of the nth harmonic (for n=1, 2, 4, 8)is plotted for different values of beam density and modulation coefficient and the points where overtaking first occurs are noted. The solution contains previously derived ballistic and space-charge theories as limiting cases.

Journal ArticleDOI
TL;DR: In this paper, an experimental study of the poisoning of the thermionic emission from barium-nickel matrix cathodes activated by aluminium and titanium hydride was carried out, and the results were largely explained on the basis of the probability of gas adsorption and its subsequent removal by free barium.
Abstract: This paper describes an experimental study of the poisoning of the thermionic emission from barium-nickel matrix cathodes activated by aluminium and titanium hydride Gases which poison the emission are oxygon, carbon dioxide and water vapour, while nitrogen, hydrogen, the inert gases and carbon monoxide do not The emission deteriorates rapidly when once a critical partial pressure of a poisoning gas is exceeded, this pressure being higher for higher cathode temperatures The critical pressures of the poisoning gases are each about 10−7 torr for normal cathode temperatures, but they decrease considerably with repeated poisonings The cathodes can be reactivated completely after a number of poisonings, before permanent impairment is observed The speed of reactivation increases with temperature and decreases with repeated poisoning The results are largely explained on the basis of the probability of gas adsorption and its subsequent removal by free barium, being produced by the activator

Journal ArticleDOI
TL;DR: In this paper, it is shown how to express the current at any point in the metal by an infinite series of increasing powers of the frequency of a sinusoidal current flowing in an energizing filament.
Abstract: Attempts to solve Maxwell's equations for regions inside electrical conductors generally meet with insuperable mathematical obstacles, unless a uniform magnetic field can be assumed to exist. In many practical instances the field will be non-uniform, since it is generated by currents flowing along wires. The lack of formulae for realistic geometrical arrangements is keenly felt in two cases. They are the prediction of eddy-current power losses and the development of electromagnetic methods for non-destructive testing A metallic body can be considered to consist of an infinite number of closed filamentary circuits, coinciding with the streamlines of induced currents. It is then shown, for the most general case, how to express the current at any point in the metal by an infinite series of increasing powers of the frequency of a sinusoidal current flowing in an energizing filament. The coefficients of the series are functions of conductor geometry, electrical conductivity and magnetic permeability, ...

Journal ArticleDOI
TL;DR: A method of detection of component functions of fewer number of variables, disjunct of which forms a given switching function, which yields bettor economy in several cases with regard to number of logical circuit elements.
Abstract: This paper describes a method of detection of component functions of fewer number of variables, disjunct of which forms a given switching function. The multi-level electronic circuit synthesized from the component functions yields bettor economy in several cases with regard to number of logical circuit elements compared with the case when the same function is synthesized from the ‘ minimal’ two-stage forms.

Journal ArticleDOI
TL;DR: In this article, it was shown that the noise figure of the d.c. pumped quadrupole amplifier can be improved by the use of bourn-cooling techniques, and a practical design of tube incorporating these techniques is described for use at 400 Mc/s.
Abstract: It is shown that the noise figure of the d.c. pumped quadrupole amplifier can be considerably improved by the use of bourn-cooling techniques. A practical design of tube incorporating these techniques is described for use at 400 Mc/s. This has a theoretical beam temperature of 1G°k which should result in a noise figure of less than I dB. It is shown that these techniques get progressively more difficult at higher frequencies. The useful limit probably lies between 3000 and 10 000 Mc/s.

Journal ArticleDOI
TL;DR: In this article, a survey of the thermal conversion phenomenon is given, and a method is described that is generally applicable to get rid of thermal conversion after heat treatment of germanium, e.g. in diffusion experiments.
Abstract: A survey is given of the thermal conversion phenomenon. A method is described that is generally applicable to get rid of thermal conversion after heat treatment of germanium, e.g. in diffusion experiments.

Journal ArticleDOI
TL;DR: In this paper, the analysis of noise effects in oscillators with one degree of freedom is extended to include nonlinearities in which the frequency of oscillation is a function of amplitude of oscillations, i.e. an r.f. form of pushing.
Abstract: The analysis of noise effects in oscillators with one degree of freedom is extended to include non-linearities in which the frequency of oscillation is a function of amplitude of oscillation, i.e. an r.f. form of pushing. The pushing contributes f.m. noise with the spectral shape of the resonant circuit, in addition to the white f.m. noise present even without pushing. Also, pushing causes correlation between a.m. noise and f.m. noise, which introduces a small but observable asymmetry into the r.f. spectrum. Comparison to previously measured magnetron spectra shows only partial agreement; the discrepancy is attributed mainly to the multi-mode nature of the magnetron resonant circuit.

Journal ArticleDOI
TL;DR: In this paper, the authors study the electrical conductivity of electrique du germanium relativernont pur, aux tres basses temperatures, lorsquo la grande majorite dos porteurs se trouve bloquee sur les centres d'impurete.
Abstract: Nous etudions la eonductivite electrique du germanium relativernont pur, aux tres basses temperatures, lorsquo la grande majorite dos porteurs se trouve bloquee sur les centres d'impurete. Dans ces conditions la mobilite est principaloment limitee par les chocs electron-phonon acoustique. Nous montrons quo l'on peut rendre compte theoriquement de l'augmentation graduelle de la densite de porteurs dans la region de pre-avalancho, unique-ment en calculant le coefficient de recombinaison non radiative Bp(E), a l'aide do la theorie des ‘ pieges geants ”; nous utilisons pour cela une fonction de distribution f(ϵ, E) dependantc du champ electrique, qui en principe n'est valablo que dans lo cas d'epuisement des impuretees. Les ordres do grandeurs trouves sont corrects, ot nous montrons quo Bp(E) varie a peu pres comme Bp(E) L'accord avec l'experienco, tres bon vers 8°K, devient plus mauvais lorsqne la temperature decroit, ce dont nous pouvons dnner une explication. We study the electrical conductivity o...

Journal ArticleDOI
TL;DR: In this paper, measurements were made of fluctuations in space-charge-limited electrical currents in cadmium sulphide diodes, and values of smoothing factor as low as 0·17 were found.
Abstract: Measurements were made of fluctuations in space-charge-limited electrical currents in cadmium sulphide diodes. Values of smoothing factor as low as 0·17 were found.

Journal ArticleDOI
TL;DR: In this article, it is shown that if the image is formed only by a ray pencil of sufficiently narrow angle (d here approximately 2 × 10−3 radian or less), then for all practical purposes the measured density reaches the theoretical maximum.
Abstract: Detailed descriptions are given of experimental investigations on how closely an electron gun of rotational symmetry can focus an electron beam into an image having a peak density equal to the theoretical maximum defined by Langmuir Particular stress is laid on the difficulty of making this study if the cathode is non-uniform in emission density or shows irregularities in emission velocity over its active surface Within the errors occasioned by such lack of uniformity and uncertainty as to the precise cathode area, the measurements to date are consistent with the following statements: (a) If the image is formed only by a ray pencil of sufficiently narrow angle (d here approximately 2 × 10−3 radian or less), then for all practical purposes the measured density reaches the theoretical maximum. This result is substantially independent of grid bias or geometry (b) The value of θ at which the gun begins to fall appreciably below the theoretical performance diminishes as the current from the cathode is...

Journal ArticleDOI
TL;DR: In this paper, the operation of an electrostatic quadrupole cyclotron wave amplifier was examined both by an extension of small-signal theory and by exact large signal calculations.
Abstract: The operation of an electrostatic quadrupole cyclotron wave amplifier is examined both by an extension of small-signal theory and by exact large-signal calculations. The variations of axial velocity, the electrostatic pump potential's contribution to the total energy and the true form of the twisted quadrupole field are taken into account. It is found that the efficiency depends on the rate of gain and, for the straightforward mode of operation discussed, is unlikely to exceed 25%.

Journal ArticleDOI
TL;DR: In this paper, the small signal theory of transverse interaction of cyclotron waves on filamentary electron beams with spatially periodic fields is discussed with particular reference to the electrostatic quadrupole amplifier.
Abstract: The small signal theory of transverse interaction of cyclotron waves on filamentary electron beams with spatially periodic fields is discussed with particular reference to the electrostatic quadrupole amplifier. Both a ballistic and a cyclotron wave theory are given and the results shown to provide two complementary descriptions of the interaction process. Gain expressions are derived for the amplification process, and the case of non-optimum pumping is discussed. Periodic energy interchange between waves without amplification is also discussed. The case of a synchronous wave input to the amplifying structure is treated and the results applied to the transverse spread of thick beams which takes place in quadrupole structures. The theories described can be applied more generally to interaction with other spatially periodic structures.

Journal ArticleDOI
TL;DR: In this article, the method of crystal growing analysed by Airapetyants and Shmelev is re-examined, taking account of one term omitted previously and thus leading to somewhat different equations for the distribution of impurities in the pulled crystal.
Abstract: The method of crystal growing analysed by Airapetyants and Shmelev ia re-examined. The present analysis takes account of one term omitted previously and thus leads to somewhat different equations for the distribution of impurities in the pulled crystal. Furthermore, the analysis indicates that the optimum experimental conditions are in practice very different from those predicted from the analysis of Airapotyants and Shmelev.

Journal ArticleDOI
TL;DR: In this article, a solution for the quasi-linear partial differential equation system, governing the motion of the electrons in the buncher gap and in the adjoining drift space, was derived.
Abstract: Rigorous analytical solution is derived for the quasi-linear partial differential equation system, governing the motion of the electrons in the buncher gap and in the adjoining drift space. The method closely follows that described by Solymar (1961 a) and so the validity of the solution breaks down after crossover. The nth harmonic of current (n =l, 2, 3, 4, 8) is plotted for a number of gap angles, space-charge coefficients (ω/ ωp) and modulation coefficients (α). It is shown that high harmonic currents can be obtained (as predicted by previous approximations) but beyond a certain critical density the approximations are no longer valid, and the harmonic content decreases drastically The solution contains the zero space-charge (ballistic) and infinitesimal gap theories as limiting cases.

Journal ArticleDOI
TL;DR: In this paper, a two-level ruby maser operated both as a pulsed amplifier and as an oscillator at 8 mm wavelengths was used to investigate adiabatic rapid passage.
Abstract: An investigation of adiabatic rapid passage has been made in ruby at 8 mm wavelengths. Performance data are given on a two-level ruby maser operated both as a pulsed amplifier and as an oscillator at these wavelengths. When amplifying, values of gain and bandwidth of up to about 14 ds and 10 Mc/ s at 1-4° k were obtained, giving root gain-bandwidth products of up to about 50 Mc/ s. In preliminary experiments using the maser as an oscillator output powers of about 70 / z/ v at 33-1 Gc/ s were obtained at 1. 4° K. The inversion technique used, which incorporates magnetic field modulation with the use of the crystal as a cavity, could be readily scaled to considerably higher frequencies.

Journal ArticleDOI
TL;DR: In this paper, a simple pinhole spectrometer is used to estimate the radial emission velocities of electrons from some typical planar cathodes, and it is fairly conclusively shown that rough cathodes can yield high apparent radii (order of 10-20 volts) under temperature limited conditions.
Abstract: A simple pinhole spectrometer is used to estimate the radial emission velocities of electrons from some typical planar cathodes. It is fairly conclusively shown that rough cathodes can yield high apparent radial velocities (order of 10-20 volts) under temperature limited conditions. These anomalous values disappear when the cathodes are physically smoothed or are operated under space charge limited conditions. A simple theory explains the findings.

Journal ArticleDOI
TL;DR: In this article, the Tit100mode is solved for a cylindrical resonator with plasma and metal walls, the plasma being treated formally as a dielectric, and the approach of Boot et al to plasma containment by radio-frequency fields is found to give results for the time-averaged force on a dense plasma which agree with results obtained by treating such a plasma as a metal.
Abstract: The Tit100mode is solved for a cylindrical resonator with plasma and metal walls, the plasma being treated formally as a dielectric. When the polarization electric field is considered explicitly together with the total electric field, the approach of Boot et al to plasma containment by radio-frequency fields is found to give results for the time-averaged force on a dense plasma which agree with results obtained by treating such a plasma as a metal. Where the electric field terminates in the plasma surface the plasma tends to be dragged out, and where magnetic field is bounded by the surface the plasma tends to be pushed in.

Journal ArticleDOI
TL;DR: In this paper, the cold tuning characteristics of a microwave magnetron coupled to a concentric annular cavity by half as many irises as are the unstrapped side resonators in the magnetron were studied.
Abstract: This paper studies the cold tuning characteristics of a microwave magnetron which is coupled to a concentric annular cavity by half as many irises as are the unstrapped side resonators in the magne...