摘要:

In the glow discharge in test diodes pulsed at high voltages and high duty cycles, spectroscopic analysis shows the presence of Ba, Sr, and Ca. It is concluded that the discharge is supported by vapors originating in particles of cathode material on the anode.

ISSN:0021-8979    

DOI:10.1063/1.1729244

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Atom ejection patterns from the Ge (100) and (110) surfaces have been studied for 100–800 eV Ne+, Ar+, Kr+, and Xe+ion bombardment as a function of target temperature in the range 0°–350°C. For ion energies below a critical value dependent on the bombarding ion, atom ejection patterns are always observed; while for higher bombarding energies the patterns appear only when the target temperature exceeds a certain value. From these data an activation energy of 1.3 eV for diffusion of defects was obtained. The experimental results indicate that very little damage to the lattice results from ion bombardment when the ion energy stays below a critical value (Ar, Ne: ∼200 eV; Kr, Xe: ∼400 eV). At higher ion energy the damage becomes more severe and higher target temperatures are required for annealing the damage between subsequent ion collisions.

ISSN:0021-8979    

DOI:10.1063/1.1729245

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The secondary electron yield due to polonium‐210 alpha particles emerging from a thin gold surface layer was determined to be 9.2 for an average alpha‐particle charge of 1.86. This result is consistent with yield observations with other high energy charged particles. The ratio of the yield due to fission fragments at normal incidence coming from UO2coatings to the yield due to alpha particles at normal incidence coming from gold was found to be about 20, substantiating the assumption that the secondary yield is proportional to the mass stopping power of the target material. A weak dependency of the yield on electric field was observed; an increase of approximately 8% resulted from a field of 3×105V/m. A slightly more pronounced field dependency was observed for the yield from fission fragments.

ISSN:0021-8979    

DOI:10.1063/1.1729246

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Measurements are reported of the absorption, emission, and excitation spectra of Eu3+in Y2O3, and also of fluorescence lifetime and quantum efficiency. An approximate level scheme is given. Conditions for laser action are calculated, and the results of a laser experiment are described. The importance of a strong ultraviolet excitation band probably corresponding to transitions fromf‐electron tod‐electron levels is indicated.

ISSN:0021-8979    

DOI:10.1063/1.1729247

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The equations of motion of a nonrelativistic particle in an attractive 1/rcentral force are developed, and integrated by a digital computer. The results are presented graphically, and representative orbits are sketched.

ISSN:0021-8979    

DOI:10.1063/1.1729248

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The Poiseuille flow of a rarefied gas between two parallel plates is analyzed numerically for an inverse Knudsen number ranging from 0 to 10.5. The Bhatnagar, Gross, and Krook model is used and the transport integrodifferential equation is reduced to a purely integral one, which is solved numerically by the discrete ordinate method.The plot of the volume flow rate vs pressure is shown to have the expected minimum; besides, it fits well with experimental results and previous approximate calculations.In particular, the results given by Takao, properly corrected, are in good agreement with ours.

ISSN:0021-8979    

DOI:10.1063/1.1729249

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Transmission electron micrographs of cleaved silicon samples show severe distortion near the cleavage marks and misorientation of the regions between marks. These results are interpreted as evidence for localized plastic deformation during cleavage.

ISSN:0021-8979    

DOI:10.1063/1.1729250

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Improved low‐energy electron diffraction equipment which yields better resolution and a proper background is described. The equipment is sufficiently flexible for measurements of total elastic and inelastic backscattering, and this is illustrated with several examples.Elastic and inelastic scattering factors are considered and illustrated by experimental data. Since they are complex, complicated, and only semiquantitatively understood, precise surface structure analysis is generally not possible at the current stage of development of this technique, though it now provides a very powerful method for characterizing surface structures. Various approximate methods for interpreting diffraction data are outlined. A preferred approach to a dynamic theory is also discussed.Other physical properties such as Fresnel zone corrections, Lorentz factors, effects of contact potential, properties of diffraction by two‐dimensional gratings, properties of averages, specimen orientation effects, effects of steps, and thermal disorder are considered and illustrated. The analytical results for x‐ray and high‐energy electron diffraction are sueful but sometimes not directly applicable.

ISSN:0021-8979    

DOI:10.1063/1.1729251

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

A mechanical fluctuation like Brownian motion takes place for colloidal particles of MgO and ZnO (particle size: 1000×1000×1000 and 5000×500×500 Å3) in a steady flow of electrons (10−5A/cm2). This is observable as a broadening of the reflections in the electron diffraction patterns obtained with a satisfactorily short wavelength (0.026–0.028 Å).The mean free path of MgO particles in recoil arising from collision with electrons was about 0.7 Å.The observations permit not only the measurement of the mean weight of colloidal particles, but also demonstrate the quantum mechanical uncertainty principle.

ISSN:0021-8979    

DOI:10.1063/1.1729252

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Niobium films 300 to 150 000 Å thick were formed by vacuum deposition using electron bombardment techniques. The films were superconducting at 4.2°K in magnetic fields as high as 30 kOe. Critical current density at 4.2°K is in the order of 106A/cm2. The superconducting transition temperature, 9.3°K for a 2300‐Å thick film, is less for thinner films. Aging effects were noted for the high‐field current‐carrying capacity.

ISSN:0021-8979    

DOI:10.1063/1.1729253

出版商:AIP    

年代:1963

数据来源: AIP