摘要:

A sensitive differential mercury manometer is described. Mercury surfaces in two arms of the manometer form plates of condensers connected to two nearly identical oscillator circuits. A change in pressure produces a change in the beat frequency of the oscillators which is measured by comparison on an oscilloscope with the output of an audiosignal generator. For 0<&Dgr;p<0.02 cm an accuracy of 0.1 to 0.2 micron of mercury is obtained. For &Dgr;pbetween 0.02 cm and the maximum measurable with the manometer (approximately 0.25 cm) the accuracy appears to be 0.1 percent or better.

ISSN:0034-6748    

DOI:10.1063/1.1745767

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

Because of the weakness of diffracted beams, it is necessary to work in the low gradient ``toe'' portion of the characteristic (D‐logE) curve. The curve shape in this region is the same for all types of x‐ray film commonly used, even when development is greatly prolonged.The shape of the entire characteristic curve is insensitive to radiation quality, but the relative speeds of different films change considerably in the range of wavelengths of interest to diffractionists.For photographic photometry, the linear density‐exposure range can be extended by proper selection of the processing conditions.

ISSN:0034-6748    

DOI:10.1063/1.1745768

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

This paper describes an adiabatic aneroid calorimeter for the measurement of the specific heat of high polymers over the temperature range −20 to 300°C.The temperature of its adiabatic jacket can be automatically recorded and, for the most part, automatically controlled, thus making possible the convenient study of temperature drifts, heat exchanges, and methods of correcting for such errors. Duplicate experiments have been carried out within an average deviation of 0.5 to 0.6 percent error, but the absolute error may be between one or two percent.

ISSN:0034-6748    

DOI:10.1063/1.1745769

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

A method of using an alternating current watt‐hour meter for the measurement of electrical energy in calorimetry is described. Reproducibility to better than 0.1 percent is readily obtainable, but the absolute accuracy depends upon the meter calibration.

ISSN:0034-6748    

DOI:10.1063/1.1745770

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

The least amount of quenching constituent,Qm,required to produce self‐quenching action in counters filled with rare gas‐polyatomic gas or vapor mixtures, was measured as a function of cathode radius and total pressure for methane, butane, and ethyl acetate in helium, neon, and argon. It was found that the variation ofQmwith cathode radius and with total pressure was in accord with the Korff‐Present theory of quenching action for counters of this type. From these minimum amounts necessary to quench, the average least number of collisions,M12, required to affect electron transfer between the rare gas ions and polyatomic molecules, was calculated for each of the nine mixtures used.M12was found to vary from about 1 collision/transfer for the ethyl acetate‐neon mixture, to over 1000 collisions/transfer for the methane‐helium mixture. The order of decreasing values ofM12in each of the three rare gases used was methane, butane, and ethyl acetate, while the order of decreasing values ofM12for any one polyatomic substance in the three rare gases was helium, argon, and neon. An attempt is made to explain these results using the theory for exchange of charge between atomic ions and molecules formulated by Kallmann and Rosen.

ISSN:0034-6748    

DOI:10.1063/1.1745771

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

A reflectionless termination design is described which, in principle, can be adapted to wave‐guide or coaxial transmission lines. Reflection coefficients of 0.001 were obtained experimentally withX‐band wave‐guide terminations. The termination comprises a section of transmission line into which is fitted a tunable sliding load. The sliding load is tuned to be reflectionless by means of the ``sliding load'' method of measuring reflection coefficients. The termination can be operated over a wide frequency range but must be retuned each time the frequency is changed.The wave‐guide circuit of the load is analyzed and design equations are derived.The reflectionless wave‐guide termination is primarily useful as a reference standard for microwave impedance bridges.

ISSN:0034-6748    

DOI:10.1063/1.1745772

出版商:AIP    

年代:1951

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745773

出版商:AIP    

年代:1951

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745775

出版商:AIP    

年代:1951

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745776

出版商:AIP    

年代:1951

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745777

出版商:AIP    

年代:1951

数据来源: AIP