van der Waals forces


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van der Waals forces:

see intermolecular forcesintermolecular forces,
forces that are exerted by molecules on each other and that, in general, affect the macroscopic properties of the material of which the molecules are a part. Such forces may be either attractive or repulsive in nature.
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References in periodicals archive ?
2] pressure should be sufficiently high so as to overcome these resistive forces caused by the surface tensions and van der Waals forces between the melted tin ball and the welding tip.
The first aim of this project is to theoretically estimate the heat transport mediated by phonons transmitting across a vacuum gap via the Van der Waals force.
Again, the macroscopic manifestation of van der Waals forces appears as a disjoining pressure term in the governing equations.
For the low-affinity binding, due to H2 less than 0 (exothermal) and S2 less than 0 (entropy decrease), the interaction between zinc ion and HSA is mainly the van der Waals forces.
Because the adhesions were very different, the team concluded that van der Waals forces don't fully explain how geckos stick to walls.
She adds that the animals grip surfaces with microscopic hairs on the soles of their feet that make close enough contact to be attracted to the surface by the minute van der Waals forces between atoms.
As an undergraduate at the University of California, Berkeley, she started a research project examining climbing gecko lizards, and ultimately discovered that geckos stick to surfaces using van der Waals forces.
At the first stage the materials are closing together to a distance where van der Waals forces are acting, and slight chemical interaction is taking place due to the plastic deformation and dislocations outlet.
Tang and Toennies [1] noted that the number of publications that mention the name van der Waals in the title, abstract or key words is currently about 2000 per annum; in their vast majority these papers refer not to the worthless equation of state nor even to the separate and worthy principle of corresponding states, but rather to van der Waals forces or molecules for which there is at most only a superficial basis to associate with van der Waals the physicist.
Then we solved the equations by considering the effect of nano scale, Van der Waals forces between the inner and outer carbon nanotubes for double-walled carbon nanotubes in equations of motion, and buckling modes by applying the boundary conditions of the simple fulcrum as sine functions," he added, noting, "Next, we calculated the natural frequencies.
Organic semiconductors differ from more conventional kinds by being held together by van der Waals forces rather than covalent bonds, and so have narrow electronic bandwidths, and charge carriers that are localized and have smaller mobilities.
Such oscillations may occur when two drops approach each other as an effect of the thermal perturbations that produce corrugations that are then amplified by the action of van der Waals forces (Vrij, 1966).