摘要:

The response of an appropriate system to a noise input is studied. The systems studied are ``generalized lossless networks'' and may include, for example, electron beams and parametrically pumped components. The noise may be introduced through several ports in an uncorrelated or correlated way. The problem is conveniently handled by the matrix analog of an eigenvector analysis. The noise input is represented as a matrix of which the diagonal elements are the self‐power density spectra, and the off‐diagonal elements the cross‐power density spectra. This matrix is resolved into ``eigenmatrices'' which are then recombined at the output in accordance with the ``2‐index eigenvalues.'' The noise invariants found by Haus (Sand &pgr;) are appropriate to a system with two degrees of freedom. For a system withndegrees of freedom, there are at leastninvariants of the noise—i.e., components of the noise that are unchanged by the system. The theory is finally applied to a generalized coupler, in which a single circuit mode is coupled to a degenerate multiplicity of beam modes, such as would occur in a hollow beam. It is shown that a ``Kompfner‐null'' condition exists. The physical significance of this condition is studied and its effect on beam noise determined.

ISSN:0021-8979    

DOI:10.1063/1.1736173

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Magnetic annealing of manganese‐ferrous ferrites and nickel‐ferrous ferrites has produced memory cores with lower temperature coefficients and higher disturb ratios than conventional square‐loop ferrites. Fifty-mil diam toroids of the composition 0.5 NiFe2O4·0.5 Fe3O4switch in approximately 1 &mgr;sec with a constant 1‐amp driving current, and have disturb ratios greater than 0.7 over the range −55° to +100°C. Physical reasons for the improved properties are discussed.

ISSN:0021-8979    

DOI:10.1063/1.1736174

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Electron interference patterns have been obtained by using an iron whisker as the electrostatic fiber of a Mo¨llenstedt [G. Mo¨llenstedt and H. Du¨ker, Z. Physik145, 377 (1956)] interferometer. The tilted fringes in the shadow pattern resemble those observed by Chambers [R. G. Chambers, Phys. Rev. Letters5, 3 (1960)] and show the relationship between flux leakage and geometrical shape of the whisker. Chambers' general model of the flux configuration is confirmed.

ISSN:0021-8979    

DOI:10.1063/1.1736175

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The mechanical and thermal stability of low‐angle boundaries in zinc single crystals was studied by methods combining metallographic techniques with x‐ray reflection microscopy and diffraction analysis. It was found that low‐angle boundaries perpendicular to the basal plane do not offer any appreciable resistance to a shearing force parallel to the basal plane if they are pure tilt boundaries, but are substantial barriers if they are asymmetrical. If the external force exceeds a critical value, these asymmetrical low‐angle boundaries become sites where fracture may occur. The strengthening effect of the asymmetrical low‐angle boundaries is attributed to the effective stress field of the screw dislocations, which are mechanically stabilized by the edge dislocations. The stress field of the screw dislocations is also responsible for the thermal instability of the asymmetrical low‐angle boundaries, which on annealing are gradually converted into pure tilt boundaries. A coarse substructure established after annealing is thermally very stable. On solidification after partial melting of the crystal, the coarse substructure is re‐established, whereas the fine substructure is entirely modified.

ISSN:0021-8979    

DOI:10.1063/1.1736176

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1736177

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1736178

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1736179

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1736180

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1736181

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1736182

出版商:AIP    

年代:1961

数据来源: AIP