ISSN:0034-6748    

DOI:10.1063/1.1748640

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

A relatively simple method, leading to an evaluation of the critical constants characteristic of a substance as well as the liquid and saturated vapor densities with varying temperatures is described. The method is employed in the case of diphenyl (C6H5·C6H5) giving values of the critical pressure, temperature and density, of 31,400 mm Hg., 528°C and .343 gms/cm3respectively.

ISSN:0034-6748    

DOI:10.1063/1.1748641

出版商:AIP    

年代:1930

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748642

出版商:AIP    

年代:1930

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748643

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

A vacuum tube voltage regulator for ac power units is described, with two novel features. First, saturation current from the filament of a thermionic tube is used as the control element; and second, a feed‐back stablization system is employed which makes it possible to obtain stable regulated voltage conditions with high sensitivity. It gives voltage regulation of 1.5% at full load unity power factor as compared to 45% with fixed excitation. The regulator also functions as an overload circuit breaker. Results of tests conducted under steady, transient, and short circuit conditions are given. Finally some further improvements are suggested.

ISSN:0034-6748    

DOI:10.1063/1.1748644

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

Attention is paid to the practical construction and application of the thermopiles. The sensitivity and quickness of reaching thermal equilibrium are both calculated by considering radiation from the receivers and conduction through the wires; the other factors are proved theoretically and experimentally to be negligible for designs found practical. In designing a thermopile for sensitivity, the whole galvanometer circuit has been considered. If we assume the approximate correctness of the Wiedemann‐Franz Law, simple optimum conditions are obtained. Maximum sensitivity is found to depend on the sensitivities, resistances and characteristic of the galvanometers available and the size of the area into which the radiation to be measured can be concentrated. If it is impossible to concentrate the light into as small a receiver as can be made, the number of junctions to be used in series can be calculated. While the theory given is general, it is especially adapted to high thermoelectric power bismuth alloy wires at room temperature and for a critically damped galvanometer circuit. Curves are plotted to facilitate the best choice of a galvanometer and best design of a thermopile for use in many experiments. The formulas were verified experimentally at room temperature. Greater sensitivity was gained by having thermopile at the temperature of liquid oxygen, as predicted by the theory.

ISSN:0034-6748    

DOI:10.1063/1.1748645

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

The vacuum thermocouples herein described had a sensitivity of about 1&mgr;Vfor 10−8Cal. sec−1falling on a receiver 0.5 mm2in area and reached practical thermal equilibrium in 0.1 sec. The sensitivity in vacuum was usually 20 to 40 times the sensitivity in air. Very short fine wires of high thermoelectric power, bismuth alloys, were soldered to a gold leaf receiver which was blackened on one side by electroplating it with platinum black. The lightness of the gold leaf receivers made the instrument extremely rugged.Greater sensitivity was obtained for visible radiation by using a receiver of silver leaf tarnished on one side with H2S; however, the sensitivity decreased for wave lengths longer than 1&mgr;.

ISSN:0034-6748    

DOI:10.1063/1.1748646

出版商:AIP    

年代:1930

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748647

出版商:AIP    

年代:1930

数据来源: AIP