Question: > 
> 1. Professor required his students to return their papers typed.
> 
> 
> 

vs

> 
> 2. Professor required that his students return their papers typed.
> 
> 
> 

Which of the examples is correct? Do they have the same meaning?
What is the preferred usage?

<http://oxfordlearnersdictionaries.com/us/definition/english/require> and <http://www.thefreedictionary.com/require> do not mention any usage differences

Answer: 
Or,
possibly, the sentence implies: Professor required his students to return his papers typed. (his in place of their)

second one seems right.
Both of these sentences are attempting to get at the same semantic meaning, and in my opinion, both are grammatically incorrect. Both are good examples of English speakers' generally woeful failure to understand the subjunctive and infinitive moods.

The first sentence should be thus:

> 
> Professor required his students return their papers typed.
> 
> 
> 

The "to" is totally superfluous. In this sentence, "return" is in the infinitive mood. Verbs are in the infinitive mood if they are being used as part of a noun phrase following the main verb of the sentence, which in this case, is the past-tense "required".

The second sentence should be thus:

> 
> Professor required that his students return their papers typed.
> 
> 
> 

OK, you got that right here - the verb "return" is in the subjunctive mood, indicating a hypothetical or possible scenario, but not one that is necessarily true, or happening right now. However, your question title provides an example of where this is missed, where you say:

> 
> to require that someone does something
> 
> 
> 

This is grammatically incorrect. You require that someone *do* something, not *does*. *Does* is present tense, intended to indicate that something is a fact. As you are requiring that something be done, it is not (necessarily) yet a fact, and so the subjunctive mood *do* is appropriate:

> 
> to require that someone do something
> 
> 
> 

Note that in English, the subjunctive form is *always* identical to the infinitive form of a verb. For that reason, I sometimes call it the "subfinitive" form.