ISSN:0034-6748    

DOI:10.1063/1.1751845

出版商:AIP    

年代:1934

数据来源: AIP

摘要:

The quinquefilar pendulum magnetometer of Weiss and Foe¨x, hitherto used only for substances of small and constant susceptibility (paramagnetic or diamagnetic) has been modified so as to be useful for small ferromagnetic specimens. For these it possesses several advantages over previous magnetometric and ballistic methods. A precise method for cutting small spheroidal specimens for the new magnetometer is described.

ISSN:0034-6748    

DOI:10.1063/1.1751846

出版商:AIP    

年代:1934

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751847

出版商:AIP    

年代:1934

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751848

出版商:AIP    

年代:1934

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751849

出版商:AIP    

年代:1934

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751850

出版商:AIP    

年代:1934

数据来源: AIP

摘要:

It is shown that moderately thick plates of both quartz and tourmaline may be successfully employed for crystal stabilization in the frequency range from 5 to 65 megacycles/sec. Specimens which were tested by a beat method exhibited a degree of stability far within that required of commercial broadcast stations. A higher degree of stability was obtained from this thicker type of plate than was obtained from a thin plate which had been ground elsewhere. The applicability of thicker plates was foreseen from the observations that at higher frequency the modes of vibrations of plates of either quartz or tourmaline are not the longitudinal or shear thickness modes, but are rather those in which the longitudinal, flexural, or torsional wave trains are propagated in a more complicated manner throughout the body of the plate. Several of these modes are briefly described. Contrary to the conclusions drawn by Straubel, these experiments indicate that tourmaline does not possess any important advantages over quartz in the stabilization of high frequencies. Most of the plates could be caused to stabilize at several widely separated frequencies. It is shown that the resonance frequencies of quartz plates are mechanically reproducible even at 60 megacycles/sec.

ISSN:0034-6748    

DOI:10.1063/1.1751851

出版商:AIP    

年代:1934

数据来源: AIP

摘要:

The application of a saturable‐core transformer to the control circuit of an ionization gauge for the purpose of maintaining constant electron current from filament to grid has proven successful.

ISSN:0034-6748    

DOI:10.1063/1.1751852

出版商:AIP    

年代:1934

数据来源: AIP

摘要:

Two single‐tube d.c. amplifiers with 7567A tubes have been constructed which are extremely stable in operation. Following the design of DuBridge and Brown, a modified balanced bridge circuit is described wherein the drifts are not due to fluctuations in battery potentials or changes in filament emission. Data on the determination of circuit constants necessary for the elimination of drifts are given. Currents of 3×10−15ampere give galvanometer deflections of one cm and readings can be obtained every 15 seconds.

ISSN:0034-6748    

DOI:10.1063/1.1751853

出版商:AIP    

年代:1934

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751854

出版商:AIP    

年代:1934

数据来源: AIP