4D-STEM at interfaces to GaN: Centre-of-mass approach & NBED-disc detection.

4D-scanning transmission electron microscopy (4D-STEM) can be used to measure electric fields such as atomic fields or polarization-induced electric fields in crystal heterostructures. The paper focuses on effects occurring in 4D-STEM at interfaces, where two model systems are used: an AlN/GaN nanowire superlattice as well as a GaN/vacuum interface. Two different methods are applied: First, we employ the centre-of mass (COM) technique which uses the average momentum transfer evaluated from the intensity distribution in the diffraction pattern.

Precise measurement of the electron beam current in a TEM.

Modern quantitative TEM methods such as the ζ-factor technique require precise knowledge of the electron beam current. To this end, a macroscopic Faraday cup was designed and constructed. It can replace the viewing screen in the projection chamber of a TEM and guarantees highly accurate measurement of the electron beam with precision only limited by the used amperemeter.

Influence of distortions of recorded diffraction patterns on strain analysis by nano-beam electron diffraction.

Images acquired in transmission electron microscopes can be distorted for various reasons such as e.g. aberrations of the lenses of the imaging system or inaccuracies of the image recording system.

Post-training cocaine administration facilitates habit learning and requires the infralimbic cortex and dorsolateral striatum.

Human drug addiction is a complex disorder, in which exogenous substances are able to recruit and maintain behaviors involved in drug taking. Many drugs that are addictive in humans are able to act on natural brain systems for learning and memory, and while many memory systems may be affected by addictive drugs, work with operant tasks has shown that addictive drugs (e.g.