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  2. Residual-resistance ratio - Wikipedia

    en.wikipedia.org/wiki/Residual-resistance_ratio

    Since resistivity usually increases as defect prevalence increases, a large RRR is associated with a pure sample. RRR is also important for characterizing certain unusual low temperature states such as the Kondo effect and superconductivity. Note that since it is a unitless ratio there is no difference between a residual resistivity and ...

  3. List of unsolved problems in chemistry - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    Protein folding problem: Is it possible to predict the secondary, tertiary and quaternary structure of a polypeptide sequence based solely on the sequence and environmental information? Inverse protein-folding problem: Is it possible to design a polypeptide sequence which will adopt a given structure under certain environmental conditions?

  4. List of dimensionless quantities - Wikipedia

    en.wikipedia.org/wiki/List_of_dimensionless...

    chemistry (Proportion of "active" molecules or atoms) Arrhenius number = Svante Arrhenius: chemistry (ratio of activation energy to thermal energy) [1] Atomic weight: M: chemistry (mass of one atom divided by the atomic mass constant, 1 Da) Bodenstein number: Bo or Bd

  5. Thermal conductivity and resistivity - Wikipedia

    en.wikipedia.org/wiki/Thermal_conductivity_and...

    The thermal conductivity of a material is a measure of its ability to conduct heat.It is commonly denoted by , , or and is measured in W·m −1 ·K −1.. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity.

  6. Thermal conductance and resistance - Wikipedia

    en.wikipedia.org/wiki/Thermal_conductance_and...

    is the thermal resistivity (K·m/W) of the sample; is the cross-sectional area (m 2) perpendicular to the path of heat flow. In terms of the temperature gradient across the sample and heat flux through the sample, the relationship is:

  7. Ballistic conduction - Wikipedia

    en.wikipedia.org/wiki/Ballistic_conduction

    In general, the resistivity of a material exists because an electron, while moving inside a medium, is scattered by impurities, defects, thermal fluctuations of ions in a crystalline solid, or, generally, by any freely-moving atom/molecule composing a gas or liquid.

  8. Van der Pauw method - Wikipedia

    en.wikipedia.org/wiki/Van_der_Pauw_method

    The van der Pauw Method is a technique commonly used to measure the resistivity and the Hall coefficient of a sample. Its strength lies in its ability to accurately measure the properties of a sample of any arbitrary shape, as long as the sample is approximately two-dimensional (i.e. it is much thinner than it is wide), solid (no holes), and the electrodes are placed on its perimeter.

  9. Electrical resistivity and conductivity - Wikipedia

    en.wikipedia.org/wiki/Electrical_resistivity_and...

    Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current.