All SEMs are supplied with a loading chamber or a sample holder where the sample is inserted. The use of aluminum stubs is recommended to load a sample in an SEM. These come in various standard sizes ...

A toxicology screen is a test that determines the approximate amount and type of legal or illegal drugs that you’ve taken. It may be used to screen for drug abuse, to monitor a substance abuse problem ...

Pew Research Center designed this study to assess the current state of online survey sampling methods – both probability-based and opt-in – and determine their accuracy on general population estimates ...