摘要:

Networks of nonlinear inductors, nonlinear capacitors, nonlinear resistors, and direct current generators are considered. If the resistors are of quasi‐linear type it is shown that such networks cannot generate alternating current or serve as power amplifiers.

ISSN:0021-8979    

DOI:10.1063/1.1722049

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

In practice one calculates the noise figure of an electron device by the Rack‐Llewellyn‐Peterson method. In this method one uses the fluctuations in current and velocity at the entrance plane as the input quantities. In a procedure such as the above, one needs to know the correlation between the velocity and current fluctuations at the entrance plane. It is shown in this paper that such a correlation between the above fluctuations is zero under certain conditions.

ISSN:0021-8979    

DOI:10.1063/1.1722050

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

The room temperature resistivity and the magnetoresistivity of AuCu have been investigated as a function of the degree of order. Measurements were made first of all on samples quenched to room temperature after reaching equilibrium at temperatures below the Curie point. In addition measurements were made on samples which were first disordered by quenching from a temperature above the Curie point, were then annealed for various lengths of time at 265°C, and were finally quenched to room temperature. The coefficient of magnetoresistivity equals 1.8×10−12and 6×10−14gauss−2, respectively, for the completely ordered and completely disordered alloy. The equilibrium curve for the magnetoresistivity shows a minimum at 365°C and a pronounced maximum at 388°C which is close to the transition temperature for the phase change of AuCu I to AuCu II. No such extremes in the value of the coefficient of magnetoresistivity occur during the annealing of a thermally disordered sample.

ISSN:0021-8979    

DOI:10.1063/1.1722051

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

A rapid and precise method is presented for approximating absolute flow curves (shear ratevsshear stress) of non‐Newtonian liquids from data obtained with rotational or capillary viscometers. It is shown that the apparent Newtonian flow curve computed from a single measurement (i.e., a single flow rate) in either type of viscometer crosses the true flow curve at a shear stress corresponding to some intermediate radius between the bob and cup radii or less than the capillary radius. If shear rate and stress are computed at the common point using the ordinary Newtonian relations for shear stress and shear rate, the point so calculated will lie on the absolute flow curve. An ``equivalent radius'' rather than a wall radius is used in the conventional Newtonian equations.The position of the equivalent radius is fairly insensitive to changes in the form of the flow curve, particularly in the case of the rotational viscometer. A method for determining the proper intermediate radius is developed and graphs are presented to facilitate this determination and permit estimation of the accuracy of the method. An example is given using data from the literature [I. M. Krieger and S. H. Maron, J. Appl. Phys.25, 72 (1954)] for a 62.2 percent GR‐S Latex slurry. Within the range of the data (slope of the log‐log flow curve varying from 1.5 to 3.0), the maximum error incurred by use of a single equivalent radius for each of two rotational viscometers was 0.1 percent for the instrument with a cup/bob radius ratio of 1.064, and 0.4 percent for the instrument with a ratio of 1.113. Accuracy can be increased by use of an iterative procedure.The method has been developed in detail only for the case of pseudo‐plastic flow, but the principle can be applied to other types of flow.

ISSN:0021-8979    

DOI:10.1063/1.1722052

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

The application of perturbation techniques to the quantitative measurement of both relative electric and relative magnetic fields in resonant cavities is described. The apparatus, procedures, advantages, and limitations are discussed, and the experimental results are compared with the calculable field distributions of a coaxial resonator. The theoretical shunt impedance andQobtained empirically agree, respectively, within one and four percent of the calculated values.

ISSN:0021-8979    

DOI:10.1063/1.1722053

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

Noise quantities at the potential minimum in the high‐frequency diode are analyzed by means of a relatively simple model which assumes that the transit angle from the cathode to the potential minimum is small and that the transit angle from the potential minimum to the anode is large. The mean‐square convection current is found to be about half full shot noise for a typical case and the mean‐square velocity is found to be the same as in the temperature‐limited case. Application of this result to an analysis of the minimum obtainable noise figure of klystrons and traveling‐wave tubes using velocity‐jump noise reduction shows that their noise figure can be reduced without theoretical limit by increasing the current density at the cathode.

ISSN:0021-8979    

DOI:10.1063/1.1722054

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

Thermal rise measurements on vacuum‐insulated electrodes subjected to steady gap voltages in the range of 80 to 100 kv show that the interelectrode prebreakdown current is composed chiefly of negatively charged particles. With aluminum electrodes the negative particles outnumber the positive particles (ions) by at least 300 to 1. With steel electrodes, the ratio is greater than 1000 to 1.

ISSN:0021-8979    

DOI:10.1063/1.1722055

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

When a charge moves along a nondispersive transmission line it induces forward and backward wave components in the line. For unaccelerated motion there is no radiation unless the charge moves with the speed of an unforced wave. For small accelerations, both radiation to the line and electromagnetic inertial effects caused by changes in the energy of the fields will be observed. The electromagnetic mass at velocities greater than the wave velocity is negative. Large accelerations can be handled by numerical computation. In the case of dispersive circuits, the charge radiates at frequencies for which the phase velocity of the circuit is equal to the velocity of the charge. This radiation is identified with Cherenkov radiation. Similar radiation takes place when a charge moves through a plasma.

ISSN:0021-8979    

DOI:10.1063/1.1722056

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722058

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722059

出版商:AIP    

年代:1955

数据来源: AIP