نتایج جستجو برای: van der waals
تعداد نتایج: 202706 فیلتر نتایج به سال:
In this paper, it is tried to find an approximate single layer equivalent for multi-layer graphene sheets based on third order non-local elasticity theory. The plates are embedded in two parameter Winkler-Pasternak elastic foundation, and also the thermal effects are considered. A uniform transverse load is imposed on the plates. Applying the non-local theory of Eringen based on third order she...
among the intermolecular interactions, the casimir and van der waals forces are the most important forces that highly affect the behavior of nanostructures. this paper studies the effect of such forces on the adhesion of cantilever freestanding nanostructures. the nanostructures are made of a freestanding nano-beam which is suspended between two upper and lower conductive surfaces. the linear s...
a mixing rule for the mixtures of hard-spheres is presented which can be reduced to the standard van der waals mixing rule at low densities. the effectiveness of the mixing rule for the size and energy parameters of lennard-jones fluid are examined by combining them with an equation of state to calculate thermodynamic properties. the results of calculation are compared with the molecular dynami...
2 Different Types of Bonds 7 2.1 Covalent Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Ionic Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.2.1 Madelung Sums . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.3 Metallic Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.4 Van der Waals Bonds . . . . . . . . . . . ....
The derivation of the van der Waals parameters for the aliphatic CH united atoms of the GROMOS96 force field is presented. The parameters n have been adjusted to reproduce the experimental enthalpies of vaporization and vapor pressures or densities of a set of nine alkanes in the liquid state at 298 Ž . K or at the boiling point in the case of methane , using a cutoff radius for the van der Waa...
We study the dependence of the heat transfer and the van der Waals friction between two semi-infinite solids on the dielectric properties of the bodies. We show that the heat transfer and van der Waals friction at short separation between the solids may increase by many orders of magnitude when the surfaces are covered by adsorbates, or can support low-frequency surface plasmons. In this case t...
The van der Waals equation of state for imperfect gases is applied to solutions of macromolecules, especially to explain the fluid-fluid phase transition in protein solutions, a phenomenon of much interest in relation to protein crystallization. The van der Waals b parameter corresponds to the total excluded volume per pair of molecules and can be calculated from independently known molecular p...
The nature of the physical interactions between Escherichia coli JM109 and a model surface (silicon nitride) was investigated in water via atomic force microscopy (AFM). AFM force measurements on bacteria can represent the combined effects of van der Waals and electrostatic forces, hydrogen bonding, steric interactions, and perhaps ligand-receptor type bonds. It can be difficult to decouple the...
The energetic barriers that atoms and molecules often experience when binding to surfaces are incredibly important to a myriad of chemical and physical processes. However, these barriers are difficult to describe accurately with current computer simulation approaches. Two prominent contemporary challenges faced by simulation are the role of van der Waals forces and nuclear quantum effects. Here...
Multi-walled hollow nanoparticles made from tungsten disulphide (WS2) show exceptional tribological performance as additives to liquid lubricants due to effective transfer of low shear strength material onto the sliding surfaces. Using a scaling approach based on continuum elasticity theory for shells and pairwise summation of van der Waals interactions, we show that van der Waals interactions ...
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