摘要:

Reactor kinetic equations are given together with the equations for fission product poisoning and temperature effects. A conceptual design of a reactor simulator is presented and the numerical values of the coefficients are listed.

ISSN:0021-8979    

DOI:10.1063/1.1721471

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

A photometric method has been developed and used to measure field‐emission electron currents as a function of the crystallographic directions found in a tungsten single crystal emission point. Data obtained indicate that the appearance of bright and dark areas on the pattern of a field‐emission projection tube can be explained by the differences in the work functions of the various crystallographic directions. The experiments also suggest that the value of the exponent of the work function needed to relate the field‐emission equation to observed data is (32) as predicted by theory. The method of analysis is independent of the need for high accuracy of electric field determination. However, it does depend on a knowledge of the electric field distribution about the surface of the emission point. In these experiments, the field distribution was an assumption based on experimental data.To insure the constancy of the electron emission required for measurement it was necessary to maintain an excellent vacuum. A method is given for the attainment and maintenance of a pressure in the region of 10−12mm of Hg.

ISSN:0021-8979    

DOI:10.1063/1.1721472

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

One of the most common nonlinearities encountered in servomechanisms design is the friction phenomenon in electromechanical systems. Conventional linear theory fails to predict its effect upon system performance. This paper extends familiar techniques to the treatment of friction nonlinearity in servosystems. Frequency‐response methods are employed throughout and the theoretical results are verified by means of an analog computer. Sliding friction and static friction are represented by describing functions which form the critical factors in determining system stability. The analysis indicates that certain series equalizers designed from linear theory may fail to achieve effective compensation in the presence of sliding and static friction. On the other hand, a subsidiary loop may avoid the stability problem while still realizing an essentially equivalent loop gain function.

ISSN:0021-8979    

DOI:10.1063/1.1721473

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

Rigorous solutions are presented of the problems of diffraction of plane electromagnetic waves by an infinitely thin, perfectly conducting, circular disk and by a circular aperture in a plane conducting screen. The analysis utilizes oblate spheroidal vector wave functions. In Part I these vector functions are defined and the expansions of plane‐polarized waves in terms of them are obtained. Part II contains the solutions of the diffraction problems.

ISSN:0021-8979    

DOI:10.1063/1.1721474

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

Rigorous solutions are presented of the problems of diffraction of plane electromagnetic waves by an infinitely thin, perfectly conducting, circular disk and by a circular aperture in a plane conducting screen. A unique solution is obtained in each case when two separate groups of the appropriate oblate spheroidal vector wave functions discussed in Part I are combined to fulfill the condition that the &phgr; component of the electric field vanish on the rims of the disk and aperture.

ISSN:0021-8979    

DOI:10.1063/1.1721475

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

The Navier‐Stokes equations have been solved to obtain a complete description of the fluid flow in a channel having a rectangular cross section and two equally porous walls. The scope has been limited to two‐dimensional incompressible steady‐state laminar flow.The solution of the flow equations leads to detailed expressions for the dependence of the velocity components and the pressure on position coordinates, channel dimensions, and fluid properties.

ISSN:0021-8979    

DOI:10.1063/1.1721476

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

When a uniform finite magnetic field passing through the cathode is used for focusing a beam of electrons, random emission at the cathode results in the electrons traveling down the beam in a helical manner. Such a rotational motion severely limits the amount of current that can be made to travel through a small tube or between closely spaced parallel plates. The amount of current transmitted through such structures is calculated in this paper and presented in the form of normalized curves. It is assumed that the current initially fills the tube or the region between the parallel plates.If an alternating electric field having a frequency comparable to the rotational frequency of the electrons is applied normal to the beam, the average electron radius of motion is increased. Should the electron beam be made to flow through a tube after the application of such an alternating electric field, the current transmission through the tube will be reduced over that when no electric field exists. The first‐order correction term for this case is calculated and presented in the form of normalized curves. The fact that the average electron radius is increased when an electric field is present implies added energy and leads to the formulation of a conductance expression relating the power in the rotational motion of the beam to the electric field normal to the beam.The current interception and the equivalent beam conductance are important in many electronic devices such as traveling‐wave tubes. The beam conductance may be quite large in some cases—on the order of that present off the axis of a helix.

ISSN:0021-8979    

DOI:10.1063/1.1721477

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

The displacement is determined at the epicenter of a homogeneous isotropic infinitely long elastic slab containing a point source of pressure waves. The source is centrally located between the slab surfaces and is taken to have a step function time dependence.The formal solution for the Laplace transform of the displacement is obtained as an infinite integral. The integration and the inversion are simultaneously accomplished by an infinite series expansion of the integrand and transformation of variables for each term of the expansion. The resultant integrated series consists of terms having the mathematical form of reflected waves which diverge individually but combine to give a finite resultant.In view of the fact that the expansion of the integrand is not valid at the upper limit of integration, a justification of the method and of the results is given.

ISSN:0021-8979    

DOI:10.1063/1.1721478

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721480

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721481

出版商:AIP    

年代:1953

数据来源: AIP