Helmut Knapp

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We identify the dynamics of an atomic force microscope ͑AFM͒ in order to design a feedback controller that enables faster image acquisition at reduced imaging error compared to the now generally employed proportional integral differential ͑PID͒ controllers. First, a force model for the tip–sample interaction in an AFM is used to show that the dynamic(More)
Scanning tunneling microscopy is based on the flow of an electrical current and thus cannot be used to directly image insulating material. It has been found, however, that a very thin film of water (about one monolayer) adsorbed to a surface exhibits a surprisingly high conductivity that is sufficient to allow scanning tunneling microscope imaging at(More)
— Self-assembly is a key coordination mechanism for large multi-unit systems and a powerful bottom-up technology for micro/nanofabrication. Controlled self-assembly and dynamic reconfiguration of large ensembles of microscopic particles can effectively bridge these domains to build innovative systems. In this perspective, we present SelfSys, a novel(More)
Microinjection is the most flexible transfection method in terms of choice of reagents to inject into cells. But this method lacks the high throughput to compete with less flexible methods like chemical- or viral-based approaches. Various approaches have been pursued to increase the throughput by automating the microinjection process. However, these(More)
Contrary to the conventional near-field superlensing, subwavelength superlens imaging is experimentally demonstrated in the far-field. The key element is termed as a Far-field SuperLens (FSL) which consists of a conventional superlens and a nanoscale coupler. The evanescent fields from the object are enhanced and then converted into propagating fields by(More)
At the interface of micro and macro world, vision plays a fundamental role in localizing targets and positioning micro-or nanorobots relative to them. Traditionally, far-field optics are used to achieve this task. However, in most practical applications optical diffraction limits resolution to the micrometer-range although image processing may provide us(More)
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