Sensors, Devices and Components

Reversible adhesion can be used to transfer or to manipulate objects. Especially if the objects are small and/or fragile their manipulation become very challenging. Intermolecular forces such as Van-der-Waals can be used to achieve a strong adhesion between the objects. Moreover, surface functionalization and the creation of nano- and microstructures can be used to improve these adhesion properties. Unfortunately, the adhesion becomes insufficient if the surfaces are wet or rough. Another problems ...

The study of mechanical properties of materials at high temperatures at the microstructural length scale requires dedicated testing setups. An accurate measurement of the sample temperature is vital for reliable testing. Most of the successful current testing platforms record the temperatures of the sample and tip near the heating sources but not at the respective surface. As a consequence, due to spatial and temporal thermal gradients a reliable surface temperature cannot be measured today. Even ...

The dynamics of complex flows and turbulences are dominated by vortices of many different scales. In general, the vortex describes the group motion of fluid elements in a circular fashion, whereas the vorticity quantizes this spinning moment of a fluid element confined to a small neighborhood.

For diagnosis of flows, conventional techniques track the movements of small particles added into the flow (e.g., Lagrangian particle tracking, LPT, and particle image velocimetry, PIV). However, ...

Evaporation cells for thin film deposition often operate under ultrahigh vacuum or special gas atmosphere, requiring long growth campaigns and short maintenance openings to preserve the best possible vacuum environment. The deposition leads to coating of the inner chamber walls, the removal of which is difficult and very time consuming. Growth control and interruptions during material deposition may require frequent operation of the closure device or shutter. The commonly used shutter (Fig. 1) ...

This novel screwless coupling, which can also be used as overload clutch, offers the possibility without additional tools to connect two rotatable elements even under extremely tight conditions, backlash-free and force fit with high precision. Due to their size, couplings known to date on the market are unsuitable for applications in the field of electronics, optics, metrology and precision engineering. Whereas thanks to the new technology, which was developed at the Max Planck Institute for Solar ...

Magnetic resonance imaging (MRI) is nowadays a leading mo¬dality for diagnostic imaging with about 100 million examinations per year worldwide. However, when invented by Paul Christian Lauterbur in 1973, MRI was too slow to allow for routine medical applications. A breakthrough was achieved in 1985 by the FLASH (Fast Low Angle Shot) technique developed by Jens Frahm and his team at the Max-Planck-Institute for Biophysical Chemistry in Göttingen, Germany. With FLASH the measuring time for a cross-sectional ...

Exploiting the benefits offered by magnetic resonance imaging (MRI) at ultra-high fields (≥ 7 Tesla) requires optimized radiofrequency (RF) coils. MRI at UHF operates in a regime where the RF wavelength is comparable to the dimensions of the sample size, resulting in an inhomogeneous distribution of the transmit field (B₁⁺) and in an impaired image quality. An array of independent transmit coils arranged in multiple rows provides the degrees of freedom to influence the ...

Speckle interferometry is an established metrology technique for the characterization of rough objects. Deformations of rough objects under a load can be determined, as well as – with the help of an additional second wavelength – the surface shape of the object under test. As an illustration, Figure 1 (left) shows the so called raw phase as a result of a deformation measurement on a metal plate. The shape and the density of the fringes indicate the response of the metal plate to the load.
Owing ...