Index of content:
Volume 12, Issue 8, August 1941
12(1941); http://dx.doi.org/10.1063/1.1769906View Description Hide Description
This paper describes a new technique for preparing thin nickel targets ranging upward in thickness from 10−6 cm. The targets are approximately 10 cm2 in area and are backed by films of cellulose acetate 5·10−6 cm thick. The periphery of the target is supported by a flexible array of fine wires.
12(1941); http://dx.doi.org/10.1063/1.1769907View Description Hide Description
Some months ago the RCA License Laboratory, in connection with television development, had occasion to make measurements on the spectral characteristics of optical filters. The conventional and elaborate equipment usually used for such purposes was not immediately at hand, and a cathode‐ray oscilloscope coupled to a few simple appurtenances was pressed into service and gave highly satisfactory results. The equipment is easily duplicated and possesses sufficient accuracy for many uses. Design considerations and constructional details are given.
12(1941); http://dx.doi.org/10.1063/1.1769908View Description Hide Description
The use of foil or mica washers to regulate absorption cell thicknesses renders difficult the rapid preparation of thin films of liquids of a determined thickness. The device described here regulates cell thickness by means of a micrometer screw and wedge arrangement. Films of non‐volatile liquids are readily prepared to within 1 micron, up to about 200 microns, without estimation.
12(1941); http://dx.doi.org/10.1063/1.1769909View Description Hide Description
Eddycurrent induction effects have been utilized in the construction of a simple electrical device whose voltage output is proportional to either rotational or vibratory accelerations. The output of the device is shown to be directly proportional to harmonic linear accelerations of small amplitude and frequencies up to at least 50 cycles per second. The utility of the device in recording certain types of vibration is also presented.
12(1941); http://dx.doi.org/10.1063/1.1769910View Description Hide Description
The practical working part of the theory of the Svensson method for the direct photography of concentration gradients is presented, along with the design of a special diagonal slit for the accurate evaluation of diffusion constants, or the concentration of material present from the areas under Svensson diagrams. Photostats of the details of construction are available.
Automatic Integration of Linear Second‐Order Differential Equations by Means of Punched Card Machines12(1941); http://dx.doi.org/10.1063/1.1769911View Description Hide Description
12(1941); http://dx.doi.org/10.1063/1.1769912View Description Hide Description
A profilograph, using a tracing point and optical lever system, makes profiles of fine textured surfaces, magnifying the elevations and depressions by as much as 6000×. With this instrument it is possible to detect surface variations as small as 0.04 micron. It is also possible to make a series of profiles along parallel paths from which topographic or relief maps can be prepared. Uses include the study of machined, lapped, and etchedsurfaces of importance in industry. The high accuracy is obtained with no more difficult machine work than the simultaneous lapping of two tapered bearings mounted on a single shaft. The use of torsion elements of special design for supporting the mirror makes the instrument relatively insensitive to vibration. These torsion elements are capable of supporting a mirror large enough to permit several reflections of the light beam, giving the instrument its high resolving power.