摘要:

Using appropriate force and displacement parameters it is shown that the response of elastomers in multiaxial stress fields is identical to their response to uniaxial stresses. These parameters were chosen from consideration of the molecular model assumed in the theory of Kuhn and Grun [Koll. Z.,101, 248 (1942)]. The required force is established to be given by|&sgr;|=(&sgr;12+&sgr;22+&sgr;32)1/2where the quantities&sgr;iare the forces along orthogonal axes on the deformed cross‐sectional area; the displacement is given by |e| = (e12+e22+e32)1/2where the quantitieseiare the strains along three orthogonal axes. The angle between the force and displacement vectors is found to be independent of the axiality of the stress field.

ISSN:0003-6951    

DOI:10.1063/1.1755114

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Pulse compression using Bragg scattering of light by an acoustic beam has been demonstrated. An ultrasonic delay line containing a frequency ramp signal is used to scatter monochromatic diverging light. If the incident and divergence angles are properly adjusted, the scattered light is focused and rapidly traverses a slit in front of a photodetector. A 1.16‐GHz, 2‐&mgr;sec pulse has been compressed to 18 nsec. Five‐nanosecond compressed pulses should be possible with this scheme.

ISSN:0003-6951    

DOI:10.1063/1.1755115

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Pulse compression of a 240‐nsec rf pulse, swept linearly over 75 MHz about 1400 MHz, has been accomplished. The method is dependent on self‐focusing associated with Bragg diffraction of light by chirped shears waves in optically anisotropic sapphire. Realization of time bandwidth products exceeding 1000, with built‐in side lobe suppression, are predicted.

ISSN:0003-6951    

DOI:10.1063/1.1755116

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Nonlinear materials havinginduced absorptionwithin a laser yield effects that contrast withbleachable absorbers. Prolonged giant pulses with greater spatial homogeneity have been observed. Mechanisms for induced absorption are suggested, with a simple model of nonlinear effects on laser emission.

ISSN:0003-6951    

DOI:10.1063/1.1755117

出版商:AIP    

年代:1967

数据来源: AIP