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  2. Crystal twinning - Wikipedia

    en.wikipedia.org/wiki/Crystal_twinning

    The relationship is defined by a symmetry operation called a twin operation. [1] [2] The twin operation is not one of the normal symmetry operations of the untwinned crystal structure. For example, the twin operation may be reflection across a plane that is not a symmetry plane of the single crystal. [1] [2]

  3. Crystallographic defect - Wikipedia

    en.wikipedia.org/wiki/Crystallographic_defect

    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.

  4. Anti-phase domain - Wikipedia

    en.wikipedia.org/wiki/Anti-phase_domain

    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 ]

  5. Lucas–Kanade method - Wikipedia

    en.wikipedia.org/wiki/Lucas–Kanade_method

    In computer vision, the Lucas–Kanade method is a widely used differential method for optical flow estimation developed by Bruce D. Lucas and Takeo Kanade.It assumes that the flow is essentially constant in a local neighbourhood of the pixel under consideration, and solves the basic optical flow equations for all the pixels in that neighbourhood, by the least squares criterion.

  6. Kirkendall effect - Wikipedia

    en.wikipedia.org/wiki/Kirkendall_effect

    The Kirkendall effect is the motion of the interface between two metals that occurs due to the difference in diffusion rates of the metal atoms. The effect can be observed, for example, by placing insoluble markers at the interface between a pure metal and an alloy containing that metal, and heating to a temperature where atomic diffusion is reasonable for the given timescale; the boundary ...

  7. Fault detection and isolation - Wikipedia

    en.wikipedia.org/wiki/Fault_detection_and_isolation

    Although the quadratic method describes the energy distribution of a signal in the joint time frequency domain, which is useful for analysis, classification, and detection of signal features, phase information is lost in the quadratic time-frequency representation; also, the time histories cannot be reconstructed with this method.

  8. Eddy-current testing - Wikipedia

    en.wikipedia.org/wiki/Eddy-current_testing

    Variations in the electrical conductivity and magnetic permeability of the test object, and the presence of defects causes a change in eddy current and a corresponding change in phase and amplitude that can be detected by measuring the impedance changes in the coil, which is a telltale sign of the presence of defects. [5]

  9. Louvain method - Wikipedia

    en.wikipedia.org/wiki/Louvain_method

    The Louvain method for community detection is a greedy optimization method intended to extract non-overlapping communities from large networks created by Blondel et al. [ 1 ] from the University of Louvain (the source of this method's name).