ISSN:0021-8979    

DOI:10.1063/1.1710453

出版商:AIP    

年代:1938

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710454

出版商:AIP    

年代:1938

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710455

出版商:AIP    

年代:1938

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710456

出版商:AIP    

年代:1938

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710457

出版商:AIP    

年代:1938

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710458

出版商:AIP    

年代:1938

数据来源: AIP

摘要:

A theoretical study of the transmission of electromagnetic waves in hollow conducting pipes of elliptic cross section, including field configurations, critical frequencies, velocities of propagation, and attenuations for the six lowest order waves. The pipe of circular cross section is treated as a special case, and the stability of waves in it for small deformation of the cross section is discussed.

ISSN:0021-8979    

DOI:10.1063/1.1710459

出版商:AIP    

年代:1938

数据来源: AIP

摘要:

A method has been devised for the determination of potentials of areas on the interior surface of the glass envelopes of vacuum tubes. Measurements by this method may be made on almost any type of finished tubes. Results obtained have been checked by a second method. Determinations of luminescent–screen potential as a function of second–anode voltage have been made for kinescope tubes under different conditions as to type of screen material, manner of bombarding the screen, beam–current density and previous electron bombardment. It was found as a general feature that as the second anode is made increasingly positive, the screen follows and remains a few volts negative with respect to the second anode until it starts to approach an upper limit of potential with respect to the cathode. When this occurs, the screen rapidly becomes more negative with respect to the second anode. Calcium–tungstate screens and clean Nonex glass surfaces have been found to reach upper limits of potentials between 2500 and 5000 volts, while willemite screens have been carried to potentials as high as 20,000 volts. The upper limit of potential for a particular type of screen varies from tube to tube. Values as different as 4000 and 20,000 volts have been obtained for willemite. In general, the upper limit of potential is found to be lowered as an effect of increased current density in the bombarding beam. Aging of a screen has been found to lower permanently its upper limit of potential. Accumulation of negative charges on the glass base of a screen and on depressed surfaces in the screen layer appears to be important in determining the upper limit of screen potential.

ISSN:0021-8979    

DOI:10.1063/1.1710460

出版商:AIP    

年代:1938

数据来源: AIP

摘要:

The probability of the transition from glow discharge to arc discharge at graphite electrodes has been investigated under carefully controlled cathode conditions. The transition probability was found to increase in an approximately linear fashion with an increase in cathode current density and glow voltage. The curve of transition probability as a function of cathode temperature was found to have a distinct maximum at a temperature of about 400° or 450°C. The probability of the transition occurring at temperatures 50° lower or higher was not more than about one‐fourth the maximum. It was also found that the frequency with which the glow to arc transitions occurred depended greatly on the previous history of the discharge and the amount of high voltage positive ion bombardment experienced by the cathode under test. A possible explanation of these results has been based on the hypothesis that it is never possible to de‐gas completely the cathode electrode even after prolonged operation in a high voltage discharge. It has been shown that the nonuniform emission of this gas from the cathode in the form of bursts from minute patches can lead to a greatly increased probability for transition from glow to arc.

ISSN:0021-8979    

DOI:10.1063/1.1710461

出版商:AIP    

年代:1938

数据来源: AIP