نتایج جستجو برای: van der waals complexes

تعداد نتایج: 338582  

2007
Joel T. Mague Lisa Linhardt Iliana Medina Mark J. Fink

The title compound, C(24)H(25)Br, packs efficiently in the crystal structure with no solvent-accessible voids and several inter-molecular H⋯H contacts approximating the sum of the van der Waals radii. The mol-ecule is quite crowded, with intra-molecular Br⋯H and C⋯H contacts ca 0.38 and 0.30 Å, respectively, less than the sum of the corresponding van der Waals radii. All cyclo-hexyl rings adopt...

2009
Ruzeng Zhu Shuwen Cui Xiaosong Wang

Theories of wetting of liquids on solid surfaces under the condition that van der Waals force is dominant are briefly reviewed. We show theoretically that Zisman’s empirical equation for wetting of liquids on solid surfaces is a linear approximation of the Young–van der Waals equation in the wetting region, and we express the two parameters in Zisman’s empirical equation in terms of the dielect...

2004
T. Vodenitcharova L. C. Zhang

This paper explores the mechanism of bending with kinking of a long single-walled carbon nanotube under pure bending with moderate bending angles. The prebuckling response was modeled using the existing continuum mechanics theory accounting for the ovalization of the cross section. The post-buckling behavior was characterized by the development of an elastic kink mechanism, considering the van ...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2015
Antonio Stocco Helmuth Möhwald

For a droplet or a bubble of dimensions below 100 nm, long-range surface forces such as long-range van der Waals forces can compete with capillarity, which leads to a size dependence of the contact angle. This is discussed in this work, where we also show that the effect cannot simply be described by a normalized line tension. We calculate interfacial profiles for typical values of van der Waal...

Journal: :The journal of physical chemistry. B 2011
Cui Zhang Leonardo Spanu Giulia Galli

We have computed the entropy of liquid water using a two-phase thermodynamic model and trajectories generated by ab initio molecular dynamics simulations. We present the results obtained with semilocal, hybrid, and van der Waals density functionals. We show that in all cases, at the experimental equilibrium density and at temperatures in the vicinity of 300 K, the computed entropies are underes...

Journal: :Physical review letters 2006
John F Dobson Angela White Angel Rubio

We show that the usual sum of R-6 contributions from elements separated by distance R can give qualitatively wrong results for the electromagnetically nonretarded van der Waals interaction between nonoverlapping bodies. This occurs for anisotropic nanostructures that have a zero electronic energy gap, such as metallic nanotubes or nanowires, and nanolayered systems including metals and graphene...

1999
N. Westbrook C. I. Westbrook A. Landragin G. Labeyrie L. Cognet V. Savalli G. Horvath V. Bagnato

After a brief introduction to the Ðeld of atom optics and to atomic mirrors, we present experimental results obtained in our group during the last two years while studying the reÑection of rubidium atoms by an evanescent wave. These involve the Ðrst measurement of the van der Waals force between an atom in its ground state and a dielectric wall, as well as the demonstration of a reÑection grati...

Journal: :Physical review letters 2007
Vassilios Yannopapas Nikolay V Vitanov

We present a first-principles method for the determination of the van der Waals interactions for a collection of finite-sized macroscopic bodies. The method is based on fluctuational electrodynamics and a rigorous multiple-scattering method for the electromagnetic field. As such, the method takes fully into account retardation, many-body, multipolar, and near-fields effects. By application of t...

1999
J. S. Wettlaufer

The effect of impurities on the surface and interfacial melting of ice is investigated in the context of the Derjaguin-Landau-Verwey-Overbeek theory by calculating van der Waals and Coulombic interactions within interfacial solution films. At high temperatures, the classical solute effect dominates the melting behavior. However, depending on the amount of impurity, as temperature decreases the ...

2005
D. Kurfeß H. Hinrichsen

Fine powders often tend to agglomerate due to van der Waals forces between the particles. These forces can be reduced significantly by covering the particles with nanoscaled adsorbates, as shown by recent experiments. In the present work a quantitative statistical analysis of the effect of powder flow regulating nanomaterials on the adhesive forces in powders is given. Covering two spherical po...

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