摘要:

Viscosity‐temperature properties of many systems are characterized by highly temperature dependent activation energies for viscous flow. It is generally recognized that structural changes taking place in the material as a function of temperature are responsible for this phenomenon. In this paper a formulation of viscosity‐temperature relations is presented in which the structural changes are explicitly taken into account by means of the formalism of short‐range order as a function of temperature. The resulting equation is shown to be a generalization of several semi‐empirical equations in current use. The equation has been applied to several glasses, high polymers, and water and has been found to describe the experimental viscosity data with high accuracy over a wide temperature range.

ISSN:0021-8979    

DOI:10.1063/1.1721376

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

Annth law device is fed by a sinusoidal signal and narrow band random noise whose spectrum lies close to the signal frequency. Its output spectrum is different from zero only in the vicinity of harmonics of this frequency. The ratioR′ of output signal power to output noise power in the vicinity of themth harmonic is computed in terms of the input signal‐to‐noise power ratioR. In general,R′(R) involves a couple of hypergeometric functions, but for smallRwe haveR′≅&Ggr;2[(m+n)/2+1]Rm/(m!)2&Ggr;(n+1)form≠0,R′≅&Ggr;2(12n+1)/[&Ggr;(n+1)−&Ggr;2(12n+1)]form=0. For largeRwe haveR′≅2R/(m2+n2).

ISSN:0021-8979    

DOI:10.1063/1.1721377

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

This paper investigates the behavior of the two‐dimensional lattice medium in the presence of electromagnetic energy. The conditions for transmission of energy by the medium are derived and studied. In particular, the effects of the various parameters of the problem (e.g., obstacle size, obstacle shape, obstacle spacing, polarization of the electromagnetic energy) on the average propagation constant and impedance function of the medium are considered. The Wigner‐Seitz cellular method is applied to the solution of the boundary value problem involving a lattice of elliptic cylindrical obstacles. Various approximate solutions are studied and appropriate functions formulated. Calculations are shown using some of these functions. Practical applications of the theoretical results are indicated, and suggestions for further research are enumerated.

ISSN:0021-8979    

DOI:10.1063/1.1721378

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721380

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721381

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721382

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721383

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721385

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721386

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1721387

出版商:AIP    

年代:1953

数据来源: AIP