ISSN:0034-6748    

DOI:10.1063/1.1751905

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751906

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751907

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

The physical meaning of resolving power when the shape of the involved diffraction pattern is unknown is experimentally studied with the double crystal x‐ray spectrometer. Our concepts of resolving power have not been extended in effect beyond the formal numerical definition and now there is need for knowing more completely the perturbations introduced by thed&lgr; interval. Sixteen different pairs of crystals, quartz and calcite, cleavage and etched surfaces, were used in measuring the widths and shapes of theK&agr; doublet lines of Mo, Cu and Ti and theL&agr;1line of Ag with the spectrometer in various parallel and antiparallel positions. The crystal diffraction patterns are evidently asymmetrical, in qualitative agreement with theory; and the asymmetry evidently varies with different pairs of crystals as well as with wave‐length. The (1, −1) width is invalidated as an adequate criterion of resolving power. New criteria for ``spectrometric'' perfection of calcite crystals are proposed and an equation is given for correcting observed x‐ray line widths for the effects of ``spectrometrically'' perfect crystals.

ISSN:0034-6748    

DOI:10.1063/1.1751908

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751909

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

A method for making extremely thin films has been developed for general use. A hole or slit in a metal plate is filled with a volatile solid and the surface is polished flat. This plate is clamped to the lower end of a liquid air container which extends into a high vacuum chamber. The material to be deposited is evaporated and covers slit and plate with a continuous film of desired thickness. The slit is then placed into the apparatus for the investigation of the film, and on evacuation the volatile material evaporates leaving the thin film supported on the slit. Camphor and naphthalene have been used as volatile material. For investigations in which residues of organic substances have to be avoided ammonium chloride, which may be driven off in vacuum at about 220°C, can be used to support the film.

ISSN:0034-6748    

DOI:10.1063/1.1751910

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

Cylinders of lumite glass 35 inches long by 10¼‐inch diameter (such as are used on gasoline filling‐station pumps) were used for dielectrics, and 0.005‐inch aluminum foil for plates. A 7‐inch glass margin was left at the ends of the cylinders. Each condenser had a capacity of 0.012 microfarad and would withstand steady voltages of over 100 kilovolts without ``flashing over.'' Sets of rings of516−inchcopper tubing were made to fit the cylinders at the edges of the plates, both inside and out. The rings provided a ``curled'' or ``rounded'' edge, in place of the rather sharp edge of the foil itself. The effect upon the ``edge corona'' and ``flash‐over voltage,'' due to various‐width bands of aluminum paint on the glass surface adjacent to the metal‐plate edges, was tried, with and without the above‐mentioned rings, in disruptive discharge and steady‐voltage tests. The results showed that the highest voltages could be obtained, without break‐over occurring, when the glass margins were chemically clean. It was also found that the best type of plate‐edge construction was either the plain aluminum‐foil edges without paint, or the curled edges (i.e., with copper rings) with a ¼‐inch band of paint.

ISSN:0034-6748    

DOI:10.1063/1.1751911

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

A new apparatus is described with which it is possible to make load‐extension diagrams for various filamentous materials. The principle of chainomatic weight application is used for the gradual application of reasonably heavy loads. An analogous construction can be used in a great many more instances where mercury or shot loading is used at the present. Load‐extension diagrams have been taken with this instrument and the relations investigated with reference to the formation of hysteresis loops at various points of stress application and load removal. These hysteresis loops and stress‐strain diagrams are characteristic for specific materials and are of assistance in their identification by physical methods. In addition to being of value from a physical and analytical viewpoint the investigation of the loading and deloading characteristics offers means of investigating the change of the physical characteristics of filamentous materials under conditions of controlled strain.

ISSN:0034-6748    

DOI:10.1063/1.1751912

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751913

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751914

出版商:AIP    

年代:1935

数据来源: AIP