ISSN:0034-6748    

DOI:10.1063/1.1769856

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

The general requirements involved in the design of a gravity meter are outlined. The construction and characteristics of a gravity meter developed by the author are discussed. The probable error of a single reading of the instrument when used in the field is 0.06 milligal.

ISSN:0034-6748    

DOI:10.1063/1.1769857

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

Two circuits are described which act as medium‐speed, single‐pole, double‐throw switches to connect two independent voltages to the input of a single‐beam cathode‐ray oscillograph. In each, a square wave is applied to the cathodes of two high‐mu pentodes, biasing them beyond cut‐off on alternate half‐cycles. The independent inputs go to the control grids and the output is taken from the common plate connection. The circuits differ in the means of generating the square wave. In one, a high voltage transformer connects to the plates of two diodes which are run at reduced heater current in order to secure voltage saturation. In the other, a transformer swings the grids of two high transconductance, sharp cut‐off television amplifier pentodes, overloading the grids on positive peaks and cutting off the plate current on negative peaks. The relative merits of the two circuits are discussed. A complete bibliography is included. A simple mechanical switch serves to change the circuit into either a two‐stage, audiofrequency amplifier or into an electronic mixer.

ISSN:0034-6748    

DOI:10.1063/1.1769858

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

An electronic switch and square wave generator for laboratory use are described. Complete instruction for construction and adjustment are included as well as diagram, parts list, voltage data and a few suggested uses. The device is entirely self‐contained and employs some of the latest types of vacuum tubes.

ISSN:0034-6748    

DOI:10.1063/1.1769859

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

This paper describes an electronic switch for use with the cathode‐ray oscillograph in the simultaneous observation of two waves. The circuit differs from similar ones described previously in that it uses a high vacuum tube trigger circuit in place of thyratrons as the switching element.

ISSN:0034-6748    

DOI:10.1063/1.1769860

出版商:AIP    

年代:1941

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1769861

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

The general principles underlying the practical design of Joule‐Thomson hydrogen liquefiers, utilizing the compressed hydrogen commercially available in cylinders, are discussed. The theory of heat interchangers is applied to these liquefiers and design formulae and data are presented. A typical design for the regenerative interchanger of a small scale liquefier is given. The liquid nitrogen requirements, expansion valve design, charcoal trap construction, and other practical aspects of these liquefiers are also discussed.

ISSN:0034-6748    

DOI:10.1063/1.1769862

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

An ionization spectrometer for intensity measurements is described. The coaxial rotation of chamber and crystal is accomplished on precision ball bearings in place of the usual conical bearing. The scales of the instrument are projected for ease in operation. A simple ``manual'' recorder is included.

ISSN:0034-6748    

DOI:10.1063/1.1769863

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

A simply constructed absorption cell with rocksalt windows is described which is capable of sealing against a pressure of 20 lb. per square inch. The use of lead gaskets having surfaces amalgamated with mercury makes unnecessary the use of organic waxes or sealing agents.

ISSN:0034-6748    

DOI:10.1063/1.1769864

出版商:AIP    

年代:1941

数据来源: AIP

摘要:

The problem of the close packing of spheres is investigated exhaustively for the case in which the spheres occupy the lattice points of a space lattice. This type of packing can be realized in boxes with plane walls as suggested by Langmuir and Nelson. It is shown that there are fifteen types of packing which differ from one another either in symmetry or in the number of contacts a given sphere makes with its neighbors. In these fifteen types, ten of the fourteen Bravais lattices are represented. The use of lattice close packing as a basis for models of more complex structures is discussed.

ISSN:0034-6748    

DOI:10.1063/1.1769865

出版商:AIP    

年代:1941

数据来源: AIP