"A technique called proton-induced X-ray emission" looks like it would function as the subject of this sentence, with "technique" being the simple subject.

"A technique...emission" is not actually a phrase because a phrase requires a noun and a verb, and "called" in this case is actually a participle (verb acting as an adjective). "Called proton-induced X-ray emission" is actually a participial phrase, or a phrase that modifies the noun, "technique." Basically, all "called" is doing is describing "technique." They're not actually saying the technique called anything; the technique is called something.

Hope that helps.

Whoops, just noticed: "a technique called proton-induced X-ray emission" IS a phrase since it has no real verb. I was thinking that it wasn't a CLAUSE. So sorry

Originally developed for detecting air pollutants, a technique called proton-induced X-ray emission, which can quickly analyze the chemical elements in almost any substance without destroying it,


Dear Nikhil, 'a technique called proton-induced X-ray emission' is a noun phrase in the subject position.
The elemebnts of the noun phrase are DETERMINER + PRE MODIFIER + HEAD NOUN + POST MIDIFIER. In this phrase, 'a' is the determiner, there is no pre modifier, 'technique' is the head noun and 'called proton-induced X-ray emission' is the post modifier in the form of the reduced adjective clause.
This stem is actually a fragment because "Originally developed for detecting air pollutants,' is a modifying phrase preceding the subject. "a technique called proton-induced X-ray emission' is the subject and "which can quickly analyze the chemical elements in almost any substance without destroying it' is the non-restrictive adjective clause modifying the subject. This sentence does not have a main verb and is thus a fragment.
I hope that was helpful.
I am attachingsome files on subjects and phrases around the subject to help you.

Guys...Thanks a lot for help ...