ISSN:0034-6748    

DOI:10.1063/1.1770112

出版商:AIP    

年代:1943

数据来源: AIP

摘要:

The circuit and performance characteristics of a simple high voltage stabilizer of the degenerative type are presented. The regulator is inserted in the positive side of the high voltage line; the design given finds particular application for electron diffraction power supplies in which the positive side is generally grounded.

ISSN:0034-6748    

DOI:10.1063/1.1770113

出版商:AIP    

年代:1943

数据来源: AIP

摘要:

The theory of the ring method for measuring shear moduli of wire specimens is developed. The resonant frequencyfsfor oscillations at right angles to the plane of the loop is related to the shear modulusnand Young's modulusEby the equationB&ngr;(&ngr;+7)=2{(2&pgr;2/3)(&ngr;2+2&ngr;+9)+5&ngr;2+46&ngr;+17},in which &ngr; = 2n/EandB=E(a/r)4/2&pgr;(1−h)mfs2·ais the radius of the wire,ris the radius of the loop,mis the mass per unit length of the specimen, andhis a small gap correction term. Measurements of shear moduli on the same wire samples of Cu and Mo by the torsion pendulum and ring methods check within the experimental errors.

ISSN:0034-6748    

DOI:10.1063/1.1770114

出版商:AIP    

年代:1943

数据来源: AIP

摘要:

A device for measuring electric charges of the order of 1.5×10−11coulomb with a probable error of approximately one percent is described. The apparatus was designed to measure the ionization produced in air by roentgenographic apparatus. For that purpose the apparatus consists of two ionization chambers, an FP‐54 electrometer tube, and an associated shielded switch. The grid of the electrometer tube is disconnected during the x‐ray exposure. The shielded switch is designed to minimize drift in the plate current while the grid is floating and to minimize extraneous effects when the grid is connected successively to the two ionization chambers.

ISSN:0034-6748    

DOI:10.1063/1.1770115

出版商:AIP    

年代:1943

数据来源: AIP

摘要:

An apparatus is described by means of which the index of refraction of opaque materials may be determined as a function of wave‐length. The method is based essentially on the determination of Brewster's angle by reflection of polarized light from a polished surface. Typical data are given, and the precision and accuracy of the method are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1770116

出版商:AIP    

年代:1943

数据来源: AIP

摘要:

An apparatus for the rapid determination of the magnetic moment of thin, circular plates of ferromagnetic material, uniformly magnetized in a direction perpendicular to their surface, is described. The method consists in rotating the specimen about a diameter near a fixed pick‐up coil and compensating the voltage induced in the latter by varying the current in a suitable compensation coil which rotates with the same phase and speed as the specimen, in a position symmetrical to it with respect to the pick‐up coil. From the value of the compensating current the magnetic moment of the disk can be calculated. The relation between the measured permanent moment and the magnetic properties of the plate material is discussed. It is shown that the method can be used for an approximate determination of the coercive force of the plate material.

ISSN:0034-6748    

DOI:10.1063/1.1770117

出版商:AIP    

年代:1943

数据来源: AIP

摘要:

A comparatively rugged optical lever system has been designed which magnified the movement of concavo‐convex Bourdon gauges by a factor of 545. The system has a reproducible null point that is independent of temperature, but varies linearly, although only slightly, with pressure. The sensitivity graph is linear, and direct pressure measurements can be made to the nearest 0.005 mm of mercury.

ISSN:0034-6748    

DOI:10.1063/1.1770118

出版商:AIP    

年代:1943

数据来源: AIP

摘要:

A closed circuit respirometer is described which circulates a given volume of water through the chamber containing the fish and equilibrates the water with a small volume of air. As oxygen is consumed by the fish, its removal from the air space is indicated manometrically, and is compensated for by measuring in oxygen from a syringe. Continuous, direct measurements can be made at any intervals and for many hours. The instrument described was used for cunners weighing from 30–70 grams and for toadfish weighing 300 grams, with oxygen consumption from 1 to 12 milliliters per hour. It showed accurately the use of110milliliter oxygen per hour.

ISSN:0034-6748    

DOI:10.1063/1.1770119

出版商:AIP    

年代:1943

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1770121

出版商:AIP    

年代:1943

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1770122

出版商:AIP    

年代:1943

数据来源: AIP