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For example, the twin operation may be reflection across a plane that is not a symmetry plane of the single crystal. [1] [2] On the microscopic level, the twin boundary is characterized by a set of atomic positions in the crystal lattice that are shared between the two orientations.
An example is the Stone Wales defect in nanotubes, which consists of two adjacent 5-membered and two 7-membered atom rings. Schematic illustration of defects in a compound solid, using GaAs as an example. Amorphous solids may contain defects. These are naturally somewhat hard to define, but sometimes their nature can be quite easily understood.
This concept has since been widely cited and the concept of a boundary object has been adopted in computer science (particularly computer supported cooperative work), information science, [4] and management, particularly when considering cross-disciplinary work and collaboration, [5] either within one organization or with the boundary object helping to focus the efforts of multiple organizations.
In materials science, a grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are two-dimensional defects in the crystal structure , and tend to decrease the electrical and thermal conductivity of the material.
In mixed oxidation state materials like magnetite, antiphase domains and antiphase domain boundaries can occur as a result of charge-ordering even though there are no changes in atom locations. [4] For example, the reconstructed magnetite (100) surface contains alternating Fe II pairs and Fe III pairs in the first subsurface layer. [ 4 ]
The original use of the term "boundary-work" for these sorts of issues has been attributed to Thomas F. Gieryn, [2] a sociologist, who initially used it to discuss the problem of demarcation, the philosophical difficulty of coming up with a rigorous delineation between what is "science" and what is "non-science". [3] Gieryn defined boundary ...
Two manifolds of the same dimension are cobordant if their disjoint union is the boundary of a compact manifold one dimension higher. The boundary of an (+)-dimensional manifold is an -dimensional manifold that is closed, i.e., with empty boundary. In general, a closed manifold need not be a boundary: cobordism theory is the study of the ...
Zener pinning is the influence of a dispersion of fine particles on the movement of low- and high-angle grain boundaries through a polycrystalline material. Small particles act to prevent the motion of such boundaries by exerting a pinning pressure which counteracts the driving force pushing the boundaries.