摘要:

A general technique for computing the power spectrum of nonlinear systems is presented, and the method is applied to the Brownian motion of a particle with idealized Coulomb damping. In this method the transition probability is obtained by solving the appropriate Fokker‐Planck equation. Then the autocorrelation function is calculated by an appropriate integration, and finally the power spectrum is found by means of the Wiener‐Khintchine relation. Comparison is made with the method of equivalent linearization, which is applicable to a wide class of nonlinear problems.

ISSN:0021-8979    

DOI:10.1063/1.1777094

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An investigation of cratering in dry sand using 22‐caliber long rifle bullets was carried out. Measurements of craters formed by bullets moving at velocities of 50 to 550 m/sec showed crater volume to vary directly with the square of the bullet velocity at the low end of this range and to approach a linear dependence on bullet velocity at the high end. An equation relating the crater volume to the bullet velocity was developed from a model which assumed hydrodynamic‐like flow behind the induced shock wave and was found to provide an excellent fit to the experimental data. It was further found that for velocities below 245 m/sec bullet deformation is small and increases rather slowly with increase in velocity. At 245 m/sec, however, an abrupt transition occurs, and the deformation increases very rapidly. Above 245 m/sec the deformation appears to become constant. This transition velocity is believed to be related to the appropriate velocity of sound in sand.

ISSN:0021-8979    

DOI:10.1063/1.1777095

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Expressions are derived for the electromagnetic radiation of current modulated electron beams which emerge from a plasma. Simple expressions are derived in the case where the dielectric constant of the plasma is zero or infinity.

ISSN:0021-8979    

DOI:10.1063/1.1777096

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1777098

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1777099

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1777100

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1777101

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1777103

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1777104

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1777105

出版商:AIP    

年代:1961

数据来源: AIP