ABSTRACT
Adhesion between small particles or particles and surfaces is important for a variety of natural phenomena and industrial processes [1]. One example is the aggregation, flow, and mixing of powders. Friction phenomena are strongly influenced by the adhesion between microcontacts [2, 3]. In order to understand and predict the aggregation of small particles, the forces between two particles in contact need to be known. When two particles in a vacuum or in a gaseous environment come close, they usually experience attractive forces such as van der Waals forces or the capillary force. Once in contact, they are inevitably deformed due to their finite elasticity.
