摘要:

The method of measurement of the dielectric properties of solid dielectrics described by S. Roberts and A. von Hippel has been applied with 3‐cm wave‐length waves in a rectangular wave guide. In this method the dielectric sample is placed at a short circuited end of the transmission line, and the dielectric properties of the sample, calculated from the position of a minimum of the standing wave and the ratio of the minimum field strength to the maximum field strength of the standing wave. A simplified procedure for calculating the dielectric properties from the measurements is presented. Values are given of the dielectric properties of some common plastic and ceramic materials at 10‐cm wave‐length and 3‐cm wave‐length, which were measured with this method.

ISSN:0021-8979    

DOI:10.1063/1.1697843

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The theory developed in Part I is applied to a number of typical deflection fields such as the fields produced by parallel plates, parallel cylinders, semi‐infinite co‐planar sheets, and bent‐plates. Graphs for the magnitude of deflection are given. An electrolytic tank potential‐plotting device is described which was used for the determination of the potential distribution of some of the deflection fields.The theory shows that the deflection is a function of the initial conditions of the electron beam before entering the field and that it is a slightly non‐linear function of the field strength. It follows that the fluorescent spot and the pattern produced on the screen of cathode‐ray tubes will show distortions. These distortions were calculated for several deflection fields and electron beam shapes; the results are shown graphically.The problem of the reduction of these distortion effects is discussed.

ISSN:0021-8979    

DOI:10.1063/1.1697844

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

A synchrotron for the production of 70‐Mev x‐rays has been built and tested. The general mode of operation, and various features of its design and construction, are discussed. Some preliminary information on the characteristics of the electron and x‐ray beams is included. This work has been supported by the Office of Naval Research.

ISSN:0021-8979    

DOI:10.1063/1.1697845

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The cathode‐ray oscilloscope is usually regarded as a means for displaying data in one or two variables as a function of time. By means of simple transformations which are easily performed electrically, it is possible to present three variable electrical data in the form of isometric or other conventional projections or as true perspective drawings. It is further possible to change the observer's viewpoint in the presentation coordinate system at will by turning range, elevation, and azimuth controls.A more elaborate but similar set of transformations permits presentation of separate pictures to the two eyes. These pictures are optically superimposed but differ in such a way as to yield stereoscopically correct perspective pictures. These pictures are fully acceptable to the eye as patterns in space.

ISSN:0021-8979    

DOI:10.1063/1.1697846

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

A least‐square application to relaxation techniques is presented wherein the mean‐square error is minimized in considering any corrections to a given set of values for the unknown function. A systematic procedure is, therefore, devised for weighting errors at various points of the lattice. The process has general applicability to various forms of equations and definitions of corresponding difference equations. As illustrations, Laplace's and the biharmonic equations are considered.

ISSN:0021-8979    

DOI:10.1063/1.1697847

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

Four homogeneous solid solutions were found in the silver‐magnesium alloy system. The &agr;‐primary solid solution of magnesium in silver has a f.c.c. structure. The &bgr;‐solid solution has a b.c.c. structure. The &ggr;‐solid solution appears to have a complicated structure. While others have identified it as hexagonal, no definite structure could be assigned to it from our diffraction data. The &dgr;‐solid solution has a h.c.p. structure of magnesium.The lattic parametera0in the &agr;‐solid solution increases with increasing magnesium concentration but exhibits a marked negative deviation from Vegard's Law. Thea0in the &bgr;‐solid solution, however, increases linearly with increasing magnesium concentration.Silver and magnesium atoms are distributed at random in the &agr;‐phase but take up preferred positions in the &bgr;‐phase. The ordering process takes place throughout the &bgr;‐phase, but is most nearly complete in the region of 50 atomic percent Mg.

ISSN:0021-8979    

DOI:10.1063/1.1697848

出版商:AIP    

年代:1947

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1697849

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The transmission data for 63 Mc and 170 Mc obtained by the U.S.N.E.L. on the San Diego coast on April 4, 1945, when a strong duct was formed near the ground, were analyzed by wave theory. The average observedM‐curve was fitted with a linear‐exponential term, and the electromagnetic field beyond the horizon was computed by the theory of normal modes. Good agreement between theory and experiment was obtained for both frequencies at a range of 32 miles (see Figs. 7 and 8). In the ranges between 32 and about 70 miles the observed variation of intensity with height agrees with theory, but the theoretical horizontal decrement is less than the observed by about 0.1 d.b./n. mile for 63 Mc, and by about 0.2 d.b./n. mile for 170 Mc. Beyond about 80 miles the observed field tends to assume a uniform distribution with height and shows little horizontal attenuation. Such an effect had been observed by the U.S.N.R.L. expedition to Antigua for 9‐cm waves under conditions of an oceanic surface duct. Its interpretation is still wanting.

ISSN:0021-8979    

DOI:10.1063/1.1697850

出版商:AIP    

年代:1947

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1697851

出版商:AIP    

年代:1947

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1697852

出版商:AIP    

年代:1947

数据来源: AIP