摘要:

Resonant transitions between the Zeeman levels of spin-polarized positive muons (μ+) implanted into iron foils have been observed at 1040 K by applying a 24·0 MHz transverse r.f. field and varying the longitudinal external magnetic field. The trapping of muons at small concentrations of crystal defects (about 10−7, i.e. of the order of magnitude of the thermal equilibrium concentration of vacancies) was detected and the local magnetic field at the traps determined.

ISSN:0950-0839    

DOI:10.1080/09500838808229610

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

It is shown here that the geometric properties of grain boundaries can be described in exactly the same way for general and coincidence lattice boundaries; the fundamental symmetries are given by a six-dimensional space group uniquely defined by the actual crystal structure and independent of the orientation of the two crystals.

ISSN:0950-0839    

DOI:10.1080/09500838808229611

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In the derivation of the classic Weibull strength distribution for brittle solids, it is assumed that the number of flaws is large. When small specimens are tested the number of flaws may not be large and the number in any one specimen may be significantly different to the expected number. In this case the effective Weibull modulus will be less than that measured from tests on large specimens.

ISSN:0950-0839    

DOI:10.1080/09500838808229612

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This Letter describes the precipitation of gold in silicon from a highly supersaturated solution. After saturation of float-zone Si at 1275°C with gold, annealing experiments were performed at 850°C for various annealing times. By means of high-resolution electron microscopy, small particles (10–20 nm diameter) consisting of a metastable gold silicide were found. From selected-area diffraction patterns we deduce an orthorhombic unit cell witha= 0·960,b= 0·768 andc= 0·690 nm.

ISSN:0950-0839    

DOI:10.1080/09500838808229613

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The viscosities of high-particle-concentration suspensions of solids in liquid media are described using a configurational entropy expression similar to that used to find the equilibrium concentration of vacancies in crystalline solids. Results are consistent with previously published findings on the viscosities of spherical particles in fluid suspensions and with results obtained in the course of this work on the viscosities of silica-water slurries.

ISSN:0950-0839    

DOI:10.1080/09500838808229614

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In this Letter a dynamical Monte Carlo method is used to calculate the strain induced in a silicon lattice by the disorder caused by ion implantation. The model is based on the prevailing role of clustered interstitials. Comparison with experiments shows that the disorder which survives spontaneous annealing is attributable to the few interstitial clusters formed within the cascade volume.

ISSN:0950-0839    

DOI:10.1080/09500838808229615

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Vickers microhardness measurements have been performed on (112) faces of n-and p-type CuInSe2single crystals at room temperature. In nearly stoichiometric samples, hardness values of 2·33 ± 0·06 GPa and 3·37 ± 009 GPa were found for n-and p-type material respectively. Preliminary results regarding hardness anisotropy and microhardness changes due to larger deviations from stoichiometry are given. At applied loads in the range 5–500 g no dependence of the microhardness on the load was found.

ISSN:0950-0839    

DOI:10.1080/09500838808229616

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Neutron diffraction measurements have been carried out on an Ni3Al0·8Mn0·2alloy at different degrees of cold-working. The Mn atoms occupy the Al sublattice in the L12-type Ni3Al structure. In the plastically deformed state, however, a long-period superstructure with a modulation of the lattice spacing appears. The superstructure can be taken as being composed of antiphase domains, where the alignment direction of the domains is parallel to the ⟨111⟩ axis of the cubic L12-type cell and a step shift occurs in close-packed planes. This structure remains even after annealing at 573 K for 15 h. Only small magnetic contributions to the diffraction patterns are observed.

ISSN:0950-0839    

DOI:10.1080/09500838808229617

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The polarity or orientation of ⟨110⟩ projected single crystals of tetrahedral compound semiconductors has been determined by high-resolution electron microscopy (HREM) at 300 kV. The method has been applied to GaSb and computer simulations show that the image contrast is the reverse of that expected intuitively. Similar results are predicted for GaAs.

ISSN:0950-0839    

DOI:10.1080/09500838808229618

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An investigation, using electron diffraction and high-resolution electron microscopy, on rapidly solidified Al-Cu–Mg alloy is reported. The splitting and the misalignment of diffraction spots are explained in terms of the coexistence of microcrystalline and micro-quasicrystalline grains, as confirmed by high-resolution electron microscopy. Diffuse scattering is mainly caused by secondary scattering between the two kinds of grain. The relationship between the structure of the rapidly solidified alloy and the structure of the crystalline phase (Al, Cu, Zn)49Mg32is discussed. An intermediate state between the crystalline and quasicrystalline states should be considered when regions larger than ∼ 10 Å are involved.

ISSN:0950-0839    

DOI:10.1080/09500838808229619

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor