ISSN:0034-6748    

DOI:10.1063/1.1769945

出版商:AIP    

年代:1942

数据来源: AIP

摘要:

A powder camera is described which was designed for the purpose of taking x‐ray photographs through an x‐ray diffraction angle of 0°—45° in a cylindrical camera of 57.3‐mm radius, to temperatures greater than 300°C. The essential features are (1) a concentric heater extending above and below the sample to minimize sharp temperature gradients; (2) easy access to the oven coils if adjustment is necessary; (3) an iron‐constantan thermocouple of small dimensions which allows one to take temperatures close to the sample; (4) a water‐cooled jacket surrounding the oven to avoid heating the film. Rotation of the sample at 1 r.p.m. is provided for. Calibration of the thermocouple and the type of capillaries are described for high temperatures.

ISSN:0034-6748    

DOI:10.1063/1.1769946

出版商:AIP    

年代:1942

数据来源: AIP

摘要:

A method of continuously measuring the level of conducting and non‐conducting liquids has been developed. The liquid to be measured occupies the inner space of a coaxial cylindrical condenser. As the level of liquid varies, the capacitance varies. The change in capacitance detunes a resonance resulting in a change of plate current through the oscillator tube.

ISSN:0034-6748    

DOI:10.1063/1.1769947

出版商:AIP    

年代:1942

数据来源: AIP

摘要:

Guard electrodes are useful devices which enable accurate dielectric measurements to be made on small samples of insulating material. They are generally applied to the electrode system of the material for the measurements of: (1) insulation resistance; (2) dielectric constant; (3) power factor. The following is a brief survey of the technique and application of guard electrodes derived from a background of considerable experience in the dielectric laboratories of the writer's company.

ISSN:0034-6748    

DOI:10.1063/1.1769948

出版商:AIP    

年代:1942

数据来源: AIP

摘要:

Mechanical means are described whereby types of equations may be graphically represented and non‐linear simultaneous equations may be solved. The procedure requires, in each case, that the equation be changed to a trigonometric form by polar transformation. Graphs are shown to illustrate the processes involved.

ISSN:0034-6748    

DOI:10.1063/1.1769949

出版商:AIP    

年代:1942

数据来源: AIP

摘要:

A circuit is described which is operated by the cardiac action current impulses in which the reading of a meter is a nearly linear function of the pulse rate. The impulses are amplified and applied to a trigger tube which sets off a gas discharge tube discharging a condenser at each beat. The charge transferred at each beat is independent of the shape of the action current wave within wide limits. The meter, shunted by a large smoothing condenser, reads the average current and is calibrated in beats per minute. The instrument may be connected to any suitable type of recording millivolt meter to obtain a continuous record of rate. The device may be used for indicating or recording the rates of any quasi‐periodic phenomenon, in the range of frequency from 20 to 400 per minute, if at each period an electrical impulse of the order of 1 mv can be provided.

ISSN:0034-6748    

DOI:10.1063/1.1769950

出版商:AIP    

年代:1942

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1769951

出版商:AIP    

年代:1942

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1769952

出版商:AIP    

年代:1942

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1769953

出版商:AIP    

年代:1942

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1769955

出版商:AIP    

年代:1942

数据来源: AIP