Laser removal of particles from solid surfaces was investigated both theoretically and experimentally. A cleaning model was established for laser-induced removal of particles from solid surfaces by taking Van der Waals force, capillary force and cleaning force into account. Laser cleaning forces are induced by fast thermal expansion of particles and/or solid surfaces irradiated by laser for dry...

The adhesion between a micro/nano-object and a microgripper end-effector is an important problem in micromanipulation. Canceling or reducing this force is a great challenge. This force is directly linked to the surface chemical structure of the object and the gripper. We propose to predict this force between a structuring surface and a micro-object with a multisphere van der Waals force model. ...

in this research, modeling of limiting flux in membrane filtration of skimmed milk as well as the results of simulation by matlab is presented. the presented model is actually a force balance approach and consists of drag, gravitational and lift forces, and forces between colloidal particles (electrostatic repulsive and van der waals attractive forces). to consider the back diffusion phenomenon...

The accuracy of topography imaging in contact force mode of atomic force microscopy (AFM) depends on the one-to-one corresponding relationship between the cantilever deflection and the tip-sample distance, whereas such a relationship cannot be always achieved in the presence of friction and incline angle of sample surface. Recently, we have developed a novel operation mode in which we keep the ...

The electric field of dipoles localized at the atomic steps of metal surfaces due to the Smoluchowski effect were measured from the electrostatic force exerted on the biased tip of a scanning tunneling microscope. By varying the tip-sample bias the contribution of the step dipole was separated from changes in the force due to van der Waals and polarization forces. Combined with electrostatic ca...

We demonstrate the controlled and reversible telescopic extension of multiwall carbon nanotubes, thus realizing ultralow-friction nanoscale linear bearings and constant-force nanosprings. Measurements performed in situ on individual custom-engineered nanotubes inside a high-resolution transmission electron microscope demonstrated the anticipated van der Waals energy-based retraction force and e...

The influence of sliding velocity on the adhesion force in a nanometer-sized contact was investigated with a novel atomic force microscope experimental setup that allows measuring adhesion forces while the probe is sliding at continuous and constant velocities. For hydrophobic surfaces, the adhesion forces (mainly van der Waals forces) remain constant, whereas for hydrophilic surfaces, adhesion...

We report the observation of a novel phenomenon, the self-retracting motion of graphite, in which tiny flakes of graphite, after being displaced to various suspended positions from islands of highly orientated pyrolytic graphite, retract back onto the islands under no external influences. Reports of this phenomenon have not been found in the literature for single crystals of any kind. Models th...

We present a mechanism for the stabilization of colloids in liquid mixtures without use of surfactants or polymers. When a suitable salt is added to a solvent mixture, the coupling of the colloid's surface chemistry and the preferential solvation of ions leads to a repulsive force between colloids that can overcome van der Waals attraction. This repulsive force is substantial in a large range o...

Classical force fields describe the interaction between atoms that are bonded or nonbonded via simple potential energy expressions. Their parameters are often determined by fitting to ab initio energies and electrostatic potentials. A direct quantum chemical guide to constructing a force field would be the atom-atom partitioning of the energy of molecules and van der Waals complexes relevant to...