摘要:

It has been shown that the organic contaminants released during the carbonate and binder decomposition of conventional oxide cathodes can be eliminated if the cathode is preconverted in a separate envelope and is then transferred to the final tube as the alkaline‐earth hydroxide. The technique used in accomplishing this lends itself readily to many laboratory applications where tube cleanliness is important. Specific applications to thermionic and secondary emission studies are described. The results indicate a definite reduction in the contamination of tube components and show improved cathode characteristics.

ISSN:0034-6748    

DOI:10.1063/1.1716682

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A novel method is described for measuring specific volume of liquids at high temperatures and pressures. The displacement of the two ends of a continuous column of the liquid is measured. One end is maintained at high temperature and pressure while the other is at normal conditions.

ISSN:0034-6748    

DOI:10.1063/1.1716683

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A nuclear magnetic resonance experiment which may be used to measure with high precision the average value of a magnetic field over an extended path in space is described. The nuclei, contained in a flowing liquid, are excited at one point and detected at another downstream from the point of excitation. Under proper conditions the average value of the magnetic field along the flow path between points of excitation and detection may be obtained therefrom. Some experimental criteria which must be met in order that this average be correctly obtained are discussed. The results of such an experiment are presented. Although the accuracy of the measurement may be somewhat less than this, line widths of 1 part in 107have been obtained.

ISSN:0034-6748    

DOI:10.1063/1.1716684

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

By intercepting on a selenium cell part of the light beam from the galvanometer in the bridge circuit of the resistance thermometer used to measure bath temperature, a signal is obtained which is used to trigger a photo‐relay via a secondary galvanometer. The photo‐relay controls the heating current in the thermostat. Design of the selenium cell mounting and accompanying circuits are described. The device holds a 50‐gal thermostat to 25° within a hunting amplitude of 0.002°C.

ISSN:0034-6748    

DOI:10.1063/1.1716685

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A method of solving anisotropic problems in the electrolytic tank has been devised. The resistance of the electrolyte along the two axes is caused to be different by means of a large number of vertical insulating strips.

ISSN:0034-6748    

DOI:10.1063/1.1716686

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The design for a relatively simple noise thermometer for use at low temperatures is presented. This thermometer has been used to measure temperatures as low as the lambda point of liquid helium with a least accuracy of 10%. Some of the properties of thermal noise are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1716687

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

An automatic neutron diffraction system for measuring the intensities of all accessible reflections in a zone is described. Crystal and counter setting information is supplied to the instrument on five‐channel punched paper tape. The angular settings are measured by means of analog‐to‐digital converters. All angle information is printed out digitally, together with the diffraction intensity information.

ISSN:0034-6748    

DOI:10.1063/1.1716688

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Measurements of the current noise and nonlinearity in the pyrolytic carbon films of 322 resistors are given. The resistances and the dimensions of the films both varied over a wide range. It is demonstrated that when the dimensions of the films are taken into account their noise and nonlinearity are highly correlated: the noise in a given film can therefore be used to estimate the nonlinearity, and conversely. In many groups of resistors of the same type the resistance change with a given applied voltage varied among resistors by a factor of more than 10, and the noise power for a given current through the resistors varied by a factor of more than 100.In the measurements of nonlinearity the resistance changes were often very small, and, consequently, were easily masked by temperature effects. A measurement method was employed in which the resistors were placed in a balanced bridge, a short high‐voltage pulse was applied to the bridge, and the resistance change was determined from the bridge output voltage. With this technique it was possible to measure resistance changes of the order of 20 ppm with an accuracy of ±3 ppm.

ISSN:0034-6748    

DOI:10.1063/1.1716689

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1716691

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1716692

出版商:AIP    

年代:1959

数据来源: AIP