トーマス・マン『選ばれし人』を読む : ヨーロッパの人間像

The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives many electrochemical reactions, and the liquid/vapor interface, which governs the uptake and release of trace gases by the oceans and cloud droplets. In this article we review some of the recent experimental and theoretical advances in our knowledge of the properties of aqueous interfaces and discuss open questions and gaps in our understanding

Ice breakloose friction

We discuss the origin of the breakloose (or static) friction force when an ice block is slid on a hard randomly rough substrate surface. Ifthe substrate has roughness with small enough amplitude (of order a 1 nm or less), the breakloose force may be due to interfacial slip andis determined by the elastic energy per unit area, Uel/A0, stored at the interface after the block has been displaced a short distance from itsoriginal position. The theory assumes complete contact between the solids at the interface and that there is no elastic deformation energyat the interface in the original state before the application of the tangential force. The breakloose force depends on the surface roughnesspower spectrum of the substrate and is found to be in good agreement with experimental observations. We show that as the temperaturedecreases, there is a transition from interfacial sliding (mode II crack propagation, where the crack propagation energy GII = Uel/A0) toopening crack propagation (mode I crack propagation with GI the energy per unit area to break the ice–substrate bonds in the normaldirection)