This article introduces an intuitive understanding of electron Ronchigrams and how they are affected by aberrations. This is accomplished through a portable web application, http://Ronchigram.com. The history of the Ronchigram, the physics which define it, and its visual features are reviewed in the context of aberration-corrected scanning transmission electron microscopy.

Significant developments in micro-electrical-mechanical systems (MEMS)-based devices have led to the commercialization of windowed gas cells that now enable atomic-resolution scanning transmission electron microscopy (STEM) observation of phenomena occurring during gas-solid interactions at atmospheric pressure. An in situ atmospheric STEM study provides information that is beneficial to correlating the structure-properties relationship of catalytic nanomaterials, particularly under realistic gaseous reaction conditions. In this article, we illustrate the advantages of this tool as applied to our study of two important systems: (1) the CO-induced Pt nanoparticle surface reconstruction at saturation coverage and (2) the ordering and Pt surface enrichment in supported Pt3Co nanoparticles.

By combining a focused inert-gas ion beam instrument and a custom magnetic-sector mass spectrometer, high spatial resolution imaging and chemical analysis are provided within a single instrument. Sub-nanometer image resolution is achieved by secondary electron (SE) imaging, limited only by the probe-size of the primary beam, while the spatial resolution for chemical mapping obtained via secondary ion mass spectrometry (SIMS) is limited mainly by beam-sample interactions to about 10 nm. This article introduces the background behind this development, describes the instrument and its various operating modes, and presents examples of its applications.

Selection of microscopes for student use involves many factors. The microscopes must stand up to daily use by students with little experience, be constantly up and running, and fit the budget requirements. Especially with student microscopes, practical aspects can be important. Thus, size, weight, cabling, and design should be taken into consideration even before the microscope and its accessories enter the decision process. If chosen carefully, educational microscopes can delight young minds in schools and universities, and, ideally, the experience will fascinate them enough that they decide to make science their profession.