Electron microscopes have certain advantages over optical microscopes: The biggest advantage is that they have a higher resolution and are therefore also able of a higher magnification (up to 2 million times). Light microscopes can show a useful magnification only up to 1000-2000 times. This is a physical limit imposed by the wavelength of the light. Electron microscopes therefore allow for the visualization of structures that would normally be not visible by optical microscopy.
berm (plural berms) A narrow ledge or shelf, as along the top or bottom of a slope. A raised bank or path, especially the bank of a canal opposite the towpath. A terrace formed by wave action along a beach. A mound or bank of earth, used especially as a barrier or to provide insulation.
A berm can be a man-made sediment barrier placed at the edge of a slope or a wall built adjacent to a ditch to guard against potential flooding. Berms are placed in flood-prone areas to protect against erosion, run off and high water.he terms berm, dike, and levee are commonly used interchangeably to describe such structures that are used for flood mitigation. The main difference between the terms is how each is built to mitigate flooding.