Distance dependence of force and dissipation in non-contact atomic force microscopy on Cu(100) and Al(111)

The dynamic characteristics of a tip oscillating in the nc-AFM mode in close vicinity to a Cu(100)-surface are investigated by means of phase variation experiments in the constant amplitude mode. The change of the quality factor upon approaching the surface deduced from both frequency shift and excitation versus phase curves yield to consistent values. The optimum phase is found to be independent of distance. The dependence of the quality factor on distance is related to 'true' damping, because artefacts related to phase misadjustment can be excluded. The experimental results, as well as on-resonance measurements at different bias voltages on an Al(111) surface, are compared to Joule dissipation and to a model of dissipation in which long-range forces lead to viscoelastic deformations

Kontrollierte Selbstorganisation von organischen Molekülen auf Ionenkristallen durch geeignete Wahl von polaren Ankergruppen

International audienc

Scanning Probe Microscopy: Imaging and Spectroscopy of Organic Layers

International audienc

Kontrollierte Selbstorganisation von organischen Molekülen auf Ionenkristallen durch geeignete Wahl von polaren Ankergruppen

International audienc

Forces with submolecular resolution between the probing tip and Cu-TBPP molecules on Cu(100) observed with a combined AFM/STM

Combined STM/AFM experiments were performed on monolayer islands of Cu-TBPP molecules on Cu(100). Pulling of single molecules on the substrate was observed and the imaging parameters were compared to STM studies. Local frequency shift vs. distance curves reveal three types of curves, which can be related to the interaction of the tip above the Cu(100) substrate, the centre of the molecule and the leg of the molecule. The frequency vs. distance curves above the legs reveal two minima, which are associated with the bending of the legs above a certain threshold value. Quantitative analysis yields force values of about 0.4 nN

Капитальный ремонт участка магистрального газопровода на переходе через автодорогу

В данной работе рассмотрено сооружение перехода магистрального газопровода через автодорогу с укладкой защитного футляра методом горизонтального бурения при капитальном ремонте действующего перехода. Рассматривается строительство нового футляра под автодорогой, протаскивание нового участка трубопровода Ду1020 мм, монтаж прилегающих участков в 16 метрах от действующей нитки МГ без отключения газа, но со снижением давления в рабочей магистрали.In this paper, we consider the construction of the transition of the main gas pipeline through a road with the laying of the protective case by horizontal drilling while overhauling the operating transition. We are considering the construction of a new case under the road, dragging a new section of the pipeline DN1020 mm, installing adjacent areas 16 meters from the current MG line without disconnecting the gas, but with a drop in pressure in the production line