摘要:

This article provides a comprehensive review of the theory, practice, and application of electron channeling patterns in the scanning electron microscope. An atlas of indexed channeling maps for the bcc, fcc, diamond cubic, and hcp systems is included with a bibliography of 240 references containing all known published work on electron channeling for crystallographic studies in the SEM.

ISSN:0021-8979    

DOI:10.1063/1.331668

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The dispersion and amplitude dependence of the recurrence phenomena in Korteweg de Vries (KdV) systems is examined both theoretically and experimentally. In a first theoretical analysis the coupled propagation of two harmonic waves is regarded. The second treatment is based upon a mathematical description of two propagating KdV solitons including the phase shift due to the interaction process. It is concluded that this phase shift reveals an important influence on the recurrence length. Finally, the theoretical results are compared with experimental data from measurements performed on LC transmission lines and with numerical solutions of the KdV equation. An excellent agreement is obtained for a large range of the nonlinear index of the normalized KdV equation.

ISSN:0021-8979    

DOI:10.1063/1.331465

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Using general thermodynamic arguments, we analyze the conversion of the energy contained in the radiation from a blackbody to useful work by a quantum system. We show that the energy available for conversion is bounded above by the change in free energy in the incident and reradiated radiation fields and that this free energy change depends upon the temperature of the receiving device. Universal efficiency curves giving the ultimate thermodynamic conversion efficiency of the quantum system are presented in terms of the blackbody temperature and the temperature and threshold energy of the quantum system. Application of these results is made to a variety of systems including biological photosynthetic, photovoltaic, and photoelectrochemical systems.

ISSN:0021-8979    

DOI:10.1063/1.331466

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Experiments are reported on the effect of buffer gases on the hyperfine frequency of rubidium 87 as used in passive rubidium frequency standards. In some mixtures of buffer gases a strong quadratic dependence of the frequency on temperature is observed. The data are explained by means of a phenomenological approach and with the help of data published previously on pure buffer gases. A comment is made on an article which appears to lead to doubtful conclusions.

ISSN:0021-8979    

DOI:10.1063/1.331467

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The theory of photothermal radiometry is extended here to include samples which are nonopaque to thermal radiation. Under certain assumptions, analytical expressions relating the detected signal to the thermal and optical properties of the sample are derived for sinusoidal modulation of the incident light intensity. Cases where the sample is a weak infrared absorber and cases of high modulation frequency can now be considered.

ISSN:0021-8979    

DOI:10.1063/1.331468

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Experiments performed on the Chanteclair accelerator to study the relativistic electron beam absorption in high and lowZthin foils are discussed. The relativistic electron beam‐target interaction is simulated with atrajeccode coupled to a hydrodynamic code. Simulations of high current thin gold foil heating experiments led to an energy deposition enhancement of about 2–3, with a rear side temperature of 15–20 eV, in agreement with experimental data. In low current experiments with lowZtargets, no anomalous deposition was observed.

ISSN:0021-8979    

DOI:10.1063/1.331469

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

An annular electron beam with less than 30 mrad of angular velocity spread, a radius of 1 cm, and a current density exceeding 0.4 MA/cm2has been generated with a magnetized foilless diode. The diode current loss is limited to less than a few percent by careful design of the tapered transition region connecting a self‐magnetically insulated vacuum transmission line to the externally magnetized foilless diode. Details of the transition section design and operating characteristics of the electron beam generator are given.

ISSN:0021-8979    

DOI:10.1063/1.331470

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Steady‐state space charge limited‐flow calculations have been carried out for an appliedB&Vthgr;magnetically insulated reflexing ion diode. Reflex ion energy spectra characteristic of a thin foil cathode and of a transparent mesh have been used. A one‐dimensional calculation shows higher ion current densities with a mesh cathode, and that the emission electron current density increases with the appliedB&Vthgr;magnetic field. The ion current density is calculated to increase slightly with radius.

ISSN:0021-8979    

DOI:10.1063/1.331471

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Details of the experimental measurement of collisional relaxation from the upper vibrational states of HD are presented. Direct overtone pumping of HD inv= 4,5, and 6 was accomplished with a pulsed visible wavelength dye laser. The change in translational energy due to collisional relaxation is measured as a function of time by a sensitive pressure transducer placed at the cell wall. Data for vibrational relaxation in pure HD and in HD:4He mixtures are presented.

ISSN:0021-8979    

DOI:10.1063/1.331464

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Absolute cross sections for the single, double, triple, and quadruple ionization of Cs+ions by electron impact have been measured from below their respective thresholds to approximately 5000 eV. These measurements have been made using a crossed beam facility operated in a pulsed beam mode. Numerous consistency checks were performed in order to identify and evaluate possible sources of experimental error.

ISSN:0021-8979    

DOI:10.1063/1.331472

出版商:AIP    

年代:1982

数据来源: AIP