摘要:

The detection statistics of a light beam with randomly fluctuating intensity are of considerable interest. This paper derives an explicit form for the photocount statistics of a laser beam in the presence of an interfering background radiation. The result can be readily utilized to obtain the over‐all photocount statistics by appropriate averaging over the random laser‐beam intensity. The technique is quite suited to experimentally determined probability density. The analysis developed in this paper is applied to the propagation of light through turbulent media. Numerical results are obtained for the over‐all photocount statistics for the two often considered probability distributions in this case: lognormal and Rice‐Nakagami. The photocount distribution for the lognormally fluctuating medium is then utilized to obtain the probability of error and information rate for a laser binary communication system.

ISSN:0021-8979    

DOI:10.1063/1.1662756

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

It is found, for pressures ∼ 1 atm and above, that the residence time for molecular oxygen, in the gas‐phase combustion region surrounding a 525‐&mgr; zirconium droplet, is of the same order of magnitude or greater than the mean dissociation time for molecular oxygen; therefore, the concentration of species are assumed to have their equilibrium values. The distribution of species over the reaction zone is calculated by means of free‐energy minimization. Calculation of the existing equilibria, under known reaction conditions, illustrates the existence or nonexistence of condensed phases. The meanings of reactive collision probability, apparent over‐all oxygen incorporation probability and minimum fractional surface oxygen incorporation, as related to droplet combustion, are discussed. Additionally, some methods by which the maximum combustion temperature of the Zr‐oxygen system has been obtained are discussed.

ISSN:0021-8979    

DOI:10.1063/1.1662757

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The behavior of misfit dislocations in (111) silver‐gold bicrystals has been studied by transmission electron microscopy and it was found that severe heating in the electron beam results in complete elimination of dislocations from the interface. The possible mechanisms involved are discussed.

ISSN:0021-8979    

DOI:10.1063/1.1662758

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Measurements of the primary electron‐beam penetration depthRin single‐crystal GaAs have been made over the electron‐beam energy range of 3–17 kV. The penetration depth is defined as the GaAs film thickness at which primary electrons of a given energyEpjust begin to emerge from the exit surface of the film with an energy of several hundred eV. The relationship betweenRandEpis R=a(Ep)b&mgr;m, witha=0.027±0.003 andb=1.46±0.05.Epis given in kV.

ISSN:0021-8979    

DOI:10.1063/1.1662759

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The thermal ionization energy for Mn acceptors in GaAs decreases with increasing density of either Mn atoms or compensators. Measurements of the correlation ofEawithNaorNdare complicated by impurity inhomogeneity. Envelope functions fitted to the data show the same energy (0.11 eV) for the infinite dilution asymptotic value as is found for the optical activation threshold.

ISSN:0021-8979    

DOI:10.1063/1.1662760

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A simple analysis is presented of the elastic field of an interfacial screw dislocation in an anisotropic two‐phase medium. Explicit expressions for the stress components of a single dislocation and of a dislocation wall are given.

ISSN:0021-8979    

DOI:10.1063/1.1662761

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The crystallization of foils of Te100−xTlxprepared by rapid cooling from the liquid state has been studied. In most cases the early stages of the amorphous‐crystalline transformation lead to a metastable cubic phase with a metallic character.

ISSN:0021-8979    

DOI:10.1063/1.1662762

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Some recent attempts to use the properties of propagating deformation bands in order to obtain information on dislocation parameters are critically discussed.

ISSN:0021-8979    

DOI:10.1063/1.1662763

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The basic assumptions of the writers' earlier paper (Ref. 2) on the properties of dislocation motion during the passage of a deformation wave are further discussed in view of the discussion of van der Beukelet al.(Ref 1). It is shown that those assumptions are physically realistic while alternative ones are inconsistent.

ISSN:0021-8979    

DOI:10.1063/1.1662764

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Recently reported work by Kliwer does not represent the first instance in which pulsed lasers were used to deposit thin films of metals for elemental analysis. Moreover, the results of a large number of elemental analyses of thin alloy films deposited by laser‐induced evaporation do not agree with the assertion that stoichiometry of the alloy is preserved through the evaporation process. The disparity between Kliwer's results and those of the present work requires that the analytical chemical significance of samples prepared by laser‐induced vaporization be assessed with caution.

ISSN:0021-8979    

DOI:10.1063/1.1662765

出版商:AIP    

年代:1973

数据来源: AIP