Give+a+brief+description+about+the+difference+between+ESEM+and+SEM

__In attempt to overcome these disadvantages of SEM, progress has been made in recent years in perfecting the environmental scanning electron microscope (ESEM). “ESEM is a new innovation in scanning microscopes specifically designed to study wet, oil bearing, or insulating materials. Polymers, biological cells, plants, soil bacteria, concrete, wood, asphalt and liquid suspensions have been observed in the ESEM without prior specimen preparation or gold coating. Samples may be examined in water vapor or other gasses such as CO2 or N2 at near atmospheric pressures due to the unique vacuum system of the ESEM.”__ http://www.egr.msu.edu/cmsc/esem/index.html__