If you check the definition of beat when used as a noun, you will see the following entry:
2.3 A person’s area of interest:
his beat is construction, property, and hotels
That is most likely the context applicable to "NIST Tech Beat".
"Beat", however, is a very flexible word. There are other meanings that can lend more interesting, figurative connotations to the word as used in the name. For example, "beat" can be used to mean "regular, rhythmic sound or movement" (same source as above), and if "Tech Beat" is taken to carry this connotation, it could simply refer to the regularity with which the publication is issued by NIST.
Another fun possibility is if the word "beat" is taken to carry the connotation of "an area allocated to a police officer to patrol". Taking "beat" to carry this context could lend a semblance of authority to the publication.
This is the beauty of language! One word can be interpreted to mean several different things, and, in some cases (like this one), all interpretations might still convey all the necessary information!