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  2. Alfvén resonator - Wikipedia

    en.wikipedia.org/wiki/Alfvén_resonator

    An Alfvén resonator or Ionosphere Alfvén resonator is a spectral resonance structure found within geomagnetic fields in the frequency range of 0.1–10 Hz. [1] First reported in 1989, they are ionospheric short-period geomagnetic variations primarily seen as nighttime phenomena and rarely observed during the day. [2]

  3. Resonance structure - Wikipedia

    en.wikipedia.org/?title=Resonance_structure&...

    Retrieved from "https://en.wikipedia.org/w/index.php?title=Resonance_structure&oldid=20068197"This page was last edited on 1 August 2005, at 19:33

  4. Impulse excitation technique - Wikipedia

    en.wikipedia.org/wiki/Impulse_excitation_technique

    In this expression, ε 1 and ε 2 are normal strains in the 1- and 2-direction and Υ 12 is the shear strain. σ 1 and σ 2 are the normal stresses and τ 12 is the shear stress. The orientation of the axes 1 and 2 in the above figure is arbitrary. This means that the values for E, G and v are the same in any material direction.

  5. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound.It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [1]

  6. Tessellated roof - Wikipedia

    en.wikipedia.org/wiki/Tessellated_roof

    The roof can be held aloft with columns, that may have branches to support and connect to the roof latticework, which stabilise the roof to create a strong structure. The material of the roof in-between or covering the tessellated frame may be a light composite, toughened glass or insulated glazing. There are roofed boulevards with columns that ...

  7. Clar's rule - Wikipedia

    en.wikipedia.org/wiki/Clar's_rule

    Clar's rule states that for a benzenoid polycyclic aromatic hydrocarbon (i.e. one with only hexagonal rings), the resonance structure with the largest number of disjoint aromatic π-sextets is the most important to characterize its chemical and physical properties. Such a resonance structure is called a Clar structure. In other words, a ...

  8. Resonance (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Resonance_(chemistry)

    Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.

  9. Molecular orbital theory - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital_theory

    When one electron is removed from an sp 3 orbital, resonance is invoked between four valence bond structures, each of which has a single one-electron bond and three two-electron bonds. Triply degenerate T 2 and A 1 ionized states (CH 4 +) are produced from different linear combinations of these four structures. The difference in energy between ...