摘要:

Icosahedral Al-Mn films have been synthesizedab initioby vapour deposition under specific conditions.

ISSN:0950-0839    

DOI:10.1080/09500838708203750

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Circular disc-crack-like defects randomly distributed on {111} planes have been discovered by 300kV transmission electron microscopy in diamond that had crystallized on non-faceted growth surfaces of mean orientation {100}. In a sample of ∼ 100 defects, disc diameters were narrowly distributed about a mean of 1·2 μm and one in seven discs were located on a coplanar stacking fault of average diameter 2 μm. Discs totally enclosed within the specimen exhibit concentric moiré fringes covering their image areas when viewed obliquely, showing them to be dilated into thin lenticles. Internal pressures, deduced from moiré-fringe counts on six lenticles, were in the range 1·5 to 1·8 GPa.

ISSN:0950-0839    

DOI:10.1080/09500838708203751

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A long-period stacking structure of 9R, which has the stacking order ABC/BCA/CAB, has been found in ultrafine cobalt particles 20–500 nm in diameter. The structure seems to have resulted from the martensitic transformation of f.c.c. cobalt on cooling to room temperature. Electron microscopy reveals the existence of heavily faulted particles, the structure of which is presumed to be 9R.

ISSN:0950-0839    

DOI:10.1080/09500838708203752

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Different ternary transition-metal-silicon alloys have been investigated in a search for quasicrystal formation. In some of these alloys a complex three-dimensional modulated structure related to quasicrystals has been discovered. The underlying basic structure is cubic with a modulation along all six ⟨110⟩* directions. The wavevectors are, however, generally slightly variable along different ⟨1l0⟩* directions destroying the cubic symmetry.

ISSN:0950-0839    

DOI:10.1080/09500838708203753

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The phonon dispersion curves for body-centred cubic transition metals are calculated using Finnis-Sinclair potentials. The accuracy of results obtained for metals of the VIa and Va groups is commented on.

ISSN:0950-0839    

DOI:10.1080/09500838708203754

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The phonon dispersion curves of the intermediate-valence compound Sm0·75Y0·25S have been calculated by using the extended three-body-force shell model. The model developed in the present study contains only four potential parameters, namelyA, B, f(r)andr0f′(r).The calculated phonon dispersion curves in all three symmetry directions are compared with the experimental curves of Mooket al.and good agreement is obtained.

ISSN:0950-0839    

DOI:10.1080/09500838708203755

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In this work results of a Monte Carlo simulation of the ion penetration in a crystalline silicon target are reported. It is shown that, contrary to the common expectation, channelling is sustained by a non-vanishing divergency of the ion beam for a nominally random orientation of the target.

ISSN:0950-0839    

DOI:10.1080/09500838708203756

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Low-temperature photoluminescence experiments have been carried out on semi-insulating GaAs crystals undoped or containing ∼5 × 1019In atoms cm−3. A broad band peaking around 0·8eV is observed which is generally related to the antisite defect AsGa. The effect of In substitution or plastic deformation is to shift this band towards higher energies by 10–25 meV. This positive energy shift is quantitatively accounted for by considering the stress fields induced by the incorporation of indium or the creation of dislocations.

ISSN:0950-0839    

DOI:10.1080/09500838708203757

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The rotational hysteresis energy has been measured as a function of the applied field for the permanent-magnet material Fe64Cr27Co9with a preferred orientation. The results are compared with the theoretical values obtained from the Shtrikman-Treves theory. The results are in good general agreement with this theory, and, from measurements of the rotational hysteresis integral and the angular dependence of the coercivity, it is concluded that changes in the magnetization occur principally by the curling mechanism.

ISSN:0950-0839    

DOI:10.1080/09500838708203758

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor