摘要:

A method is described for measuring time‐average concentration profiles in the fully developed turbulent wake of a circular cylinder having a porous wall through which a solution of electrolyte was flowing. The study was carried out in the flow field of a water tunnel. The sensing element employed was an electrical conductivity probe. The method involves the use of a thermal averaging device and a sensitive recording dc bridge. The method is very sensitive and is capable of high precision.

ISSN:0034-6748    

DOI:10.1063/1.1717393

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A new method of high speed oscillography has been investigated. This makes use of four‐pole lenses which enable the deflection of the beam to be magnified in only one desired direction. By magnifying the deflection by a factorkin both directions as in the conventional oscilloscopes, one loses in intensity by a factork8/3. If, however, a magnification in one direction is used, the loss is onlyk4/3.

ISSN:0034-6748    

DOI:10.1063/1.1717394

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A complete description is given of a narrow‐gapped coaxial cylinder viscometer, particularly designed for applicability to non‐Newtonian fluids. Included are details of mechanical construction, torque and speed measuring systems, and operating characteristics.

ISSN:0034-6748    

DOI:10.1063/1.1717395

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An apparatus has been constructed to measure theM‐Hcharacteristics of thin magnetic films plated on a nonmagnetic wire substrate. The films were uniaxially anisotropic and the characteristics were to be measured in the circumferential direction. Cancellation of air coupling and spurious noises was accomplished by means of a bridge circuit which used magnetic coupling to provide the necessary isolation for the various signals. The characteristics of the bridge are derived.

ISSN:0034-6748    

DOI:10.1063/1.1717396

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A hybrid combination of electronic and magnetic amplifiers has been successfully and reliably utilized over the past five years in a variable, precision regulated, low voltage high current supply for a charged particle deflection magnet. Controlled current range is from 5–200 amp at up to 40 v. Despite the nonlinear impedance presented by the magnet's shielded coils, appropriate feedback loops permit an essentially critically damped 0.01% control response throughout the entire current range. As crucially reflected in the magnet's field, regulation and ripple are <0.01%.

ISSN:0034-6748    

DOI:10.1063/1.1717397

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The electron beam analyzer reported here is intended to investigate the current density distribution of a high current‐density electron beam for use with a klystron or a traveling‐wave tube. A pair of piezo‐electric elements of barium titanate ceramic is used to drive a vibrating, pinholed target for the purpose of sampling the beam to be investigated. This enables direct observation of the current density distribution on a cathode ray oscilloscope screen at any part of the electron beam under investigation, including the part very close to the anode aperture of the electron gun. This is one of the most important parts in our present investigation and yet it is inherently impossible to observe the entire picture of the distribution in this vicinity when a conventional method as, for example, that described by Ashkin is used. Both PPI and A presentations are possible. Only qualitative measurements can be made by the former type of presentation which, however, is indispensable for the purpose of observing the entire picture of the distribution at a glance. The latter, on the other hand, is suitable for quantitative measurements of the distribution along a straight line on a cross section of the beam. The analyzer is so designed and built that either one of these two types of presentation can be selected simply by turning a switch for rapid and accurate measurements. Utmost care is paid in the design and construction of the vacuum and mechanical systems as well as of the associated electrical circuitry with the intention of assuring satisfactory over‐all performance and for the convenience of the experimenters. As the result, for example, the pressure in the useful part of the vacuum chamber, with all the complications of the entire setup, could be made to as low as 10−6∼10−7mm Hg under typical operating conditions. The merits and demerits of the new analyzer are fully discussed with particular reference to the resolving power of the observed pattern. Possible causes of errors which might be introduced to the observed results are also considered.

ISSN:0034-6748    

DOI:10.1063/1.1717398

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An instrument for the measurement of gradients in the earth's magnetic field has been constructed. The gradiometer, of 15‐ft base length, is capable of operation for long periods with an error less than 20 &ggr; (5 &ggr;/m). Detectors are of the tuned, second harmonic flux gate type. An automatic ambient‐field nulling feature has been introduced to ease the requirement for exact matching of the magnetic characteristics of the gradient detectors.

ISSN:0034-6748    

DOI:10.1063/1.1717399

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A capacitor method for measuring the velocity of a plane, conducting surface is described. An advantage of the method is that the signal voltage developed is essentially proportional to the velocity of the surface instead of to the displacement. Consequently, the method is useful in measuring a surface velocity which persists only over a small displacement interval.

ISSN:0034-6748    

DOI:10.1063/1.1717400

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1717402

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1717403

出版商:AIP    

年代:1961

数据来源: AIP