The resolution of helium ion scanning microscopes working in the secondary electron emission mode is theoretically estimated in the energy interval of E = 0.3-100 keV. The corresponding probe diameter improves with energy from 1.0 to 0.2 nm. A theoretical probe diameter of 0.25 nm can be obtained by use of a standard three-electrode objective lens of electrostatic microscopes. The most importan...

The strong field localization generated between closely placed metal particles excited by electromagnetic radiation induces intense forces on small polarizable objects. In this study we investigate the optical forces that can be generated in the vicinity of metal nanoparticle clusters using fully electrodynamic numerical simulations. The influence of the cluster configuration as well as of the ...

Dual-energy X-ray computed tomography (DECT) is a powerful tool for non-destructive evaluation for security. In security applications where DECT is used for scanning checked luggage, many different materials may be scanned in various degrees of clutter and metal objects are common. Conventionally, fi ltered back-projection (FBP) is used for image formation and there is no unifi ed treatment of ...

Electromagnetic tracking systems (EMTS) are utilized to track surgical instruments during navigated interventions. Compared to optical tracking technologies, the non-line-of-sight feature is the biggest advantage of EMTS. However, significant distortions due to nearby metallic objects and a small working volume are serious drawbacks preventing ETMS from being widely used. We worked on developin...

X-ray computed tomography (CT) images of patients bearing metal intracavitary applicators or other metal foreign objects exhibit severe artifacts including streaks and aliasing. We have systematically evaluated via computer simulations the impact of scattered radiation, the polyenergetic spectrum, and measurement noise on the performance of three reconstruction algorithms: conventional filtered...

Don’t put metal objects in the microwave’ is common safety advice. But why? Here we describe demonstration experiments involving placing household metallic objects in a microwave oven. These allow a better understanding of the interaction of microwaves with materials. Light bulbs and discharge lamps can also be used in instructive demonstrations. M This article features online multimedia enhanc...

There is increasing demand in the field of dental and medical radiography for effective metal artifact reduction (MAR) in computed tomography (CT) because artifact caused by metallic objects causes serious image degradation that obscures information regarding the teeth and/or other biological structures. This paper presents a new MAR method that uses the Laplacian operator to reveal background ...

In the absence of light, the weakly electric fish Gnathonemus petersii detects and distinguishes objects in the environment through active electrolocation. In order to test which features of an object the fish use under these conditions to discriminate between differently shaped objects, we trained eight individuals in a food-rewarded, two-alternative, forced-choice procedure. All fish learned ...

Robust robotic perception and manipulation of household objects requires the ability to detect, localize and manipulate a wide variety of objects, which may be mirror reflective like polished metal, glossy like smooth plastic, or transparent like glass; for example, picking a metal fork out of a sink full of running water or screwing a metal nut onto a bolt. Existing perceptual approaches based...

rom the detection of buried treasure to the detection of landmines and unexploded ordnance, the history of metal detectors is long and varied. This article reviews the basic technology for detecting metal objects using electromagnetic induction techniques. Working with the U.S. Army Night Vision and Electronic Sensors Directorate and other government agencies, APL has developed a number of adva...