摘要:

Total current spectroscopy (TCS) has been used to study the growth of gold and silver on {100} vanadium surfaces. A slow transition from TCS curves characteristic of vanadium to curves characteristic of the noble metals is observed, accompanied by an increase in the net work function-more rapid for silver than for gold. Vanadium characteristics are lost from the TCS curves for mean overlayer thicknesses ≳ 15 A, and a simple analysis shows that the thickness of the surface zone from which TCS signals originate is approximately given by the electron mean free path. Observations of progressive attenuation of a characteristic vanadium feature with increasing mean thickness of overlayer permits separation into stages of nucleation and growth. There is a critical nucleus size of ≃ 2 A for silver and ≃ 4 A for gold.

ISSN:0033-7579    

DOI:10.1080/00337577708233767

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A computer calculation of light ion (200–800 keV protons and helium) scattering from a tungsten single crystal model with a (110)-type surface is presented. An axis (100) is considered. Thermal vibrations in 3 dimensions have been incorporated. The number, i.e. fraction, and spatial distribution of reflected ions for some angular scans are presented in an appendix. The importance of trajectory histories is demonstrated. 3 regimes of scattering behaviour as a function of the incidence angle ψ in to the string in the surface are found:

ISSN:0033-7579    

DOI:10.1080/00337577708233768

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A high voltage electron microscope was used to study loop formation in thin foils of pure and impure nickel. The effects of variation in flux, impurities and temperature were examined in the light of an existing theory for loop nucleation and growth. It was found that diffusion of point defects to the foil surfaces had to be taken into account for all quantitative work. The corrected volume densities of defect clusters produced at various temperatures between room temperature and about 500 K are in agreement with the theory and the results suggest that the migration energy of a free self-interstitial in nickel is (0.21 ± 0.05) eV and that its binding energy with a silicon atom is (0.26 ± 0.06) eV. At higher temperatures the experimental volume densities show considerable deviation from theoretical predictions, but this deviation has been shown to arise from the instability of di-interstitials. From the experimental data obtained at higher temperatures, the dissociation energy of a di-interstitial may be determined. This was found to be (0.8 ± 0.1) eV for nickel.

ISSN:0033-7579    

DOI:10.1080/00337577708233769

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Specimens of Cu and CuAu alloy were irradiated at 4.2 K in a thermal-neutron flux to a resistivity change of 300 pΩcm, yielding a defect concentration of 1 × 10−6. All samples were simultaneously annealed. By constructing isochrones from isothermal anneals at different temperatures, it could be shown that a further recovery substage ID exists between the well-known IDand IErecovery substages. IDcannot be found if conventional sequential isochrones are used.

ISSN:0033-7579    

DOI:10.1080/00337577708233770

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

In order to check a recently suggested interaction between high energy electrons from radioactive β-decay and organic molecules dissolved in water, crystallization of D, L-sodium-ammonium tartrate was studied in the presence of32P. The results substantiate the existence of such an interaction. Irradiated samples yielded more crystalline material than controls, the relative difference was 20.5%. The possible interference of contaminations as well as the relation of these findings to the role of radioactive β-decay in chemical evolution is discussed.

ISSN:0033-7579    

DOI:10.1080/00337577708233771

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

In the present work, a new and direct method for measuring neutron doses is achieved through induced changes in the bulk electric conductivity of cellulose acetate after being irradiated with neutrons having average energy of 4.5 MeV.

ISSN:0033-7579    

DOI:10.1080/00337577708233772

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The forward form of the Boltzmann equation is employed to obtain a new closed form expression for the path length distribution function of particles emitted from a plane source in an infinite medium. The power law cross section is used and the equations are solved by the use of Mellin transforms. We can obtain the spatial moments of the distribution function and, for certain restrictive conditions, study the influence of electronic stopping upon them. An asymptotic analysis is developed which enables the large-depth behaviour deduced earlier by Winterbon to be recovered and extended.

ISSN:0033-7579    

DOI:10.1080/00337577708233773

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The published data on liquidn-alkanes radiolysis at low doses and temperatures of 0–25°C are considered.

ISSN:0033-7579    

DOI:10.1080/00337577708233774

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The results of experimental study of the 10–35 keV argon ion scattering by the (100) face of a copper cyrstal are presented. The results obtained are discussed in terms of the model of correlated scattering by an atom pair and a close-Dacked atomic row.

ISSN:0033-7579    

DOI:10.1080/00337577708233775

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337577708233776

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor