Left: Images of fluorescent particles that are above, at and below (top to bottom) the vertical position of best focus of a microscope. Calibrating the effects of lens aberrations on the apparent ...

Measuring the volume, motion and contents of microscopic droplets is important for studying how airborne viruses spread (including those that cause Covid-19), how clouds reflect sunlight to cool the ...

It’s a problem that few of us will ever face, but if you ever have to calibrate your scanning electron microscope, you’ll need a resolution target with a high contrast under an electron beam. This ...