Jimmi,
you know I've been thinking... there is a potential issue with intimidation, but it is not exactly the same as size.
men in some situations, presumably including prison, may learn to behave in a threatening manner, to protect themselves. I know I had to when I worked in the meat market. If I didn't, some of those guys would have "eaten my lunch" every day.
But any kind of threatening body language or speech, is out of bounds in an office setting. We have to learn even to take some verbal abuse, without ever threatening physical retaliation, as we might in an all male, physical work setting.
It can be very frustrating to be read out by some twit, or seriously mistreated, and never respond by losing our temper. But even shouting in an office environment can be cause for dismissal, regardless of who is right.
Presumably you are already getting some practice at this in grad school, but if this rings a bell, you might want some professional advice and coaching, better than just our opinions here.
It can be done. You just say goodbye to those old attitudes of survival forever, and use exercise, and maybe meditation or worship if that's your thing, to blow off steam.
Ultimately, the fact is the "way of yielding" is more powerful, as both Jesus and Jigoro Kano [founder of modern judo] knew, but it takes persistence.
You are a new man now, in every way, and probably you have already dealt with this. Putting people at ease is all about smiling and remaining calm, and respecting their words, their feelings, and their space. There are many large but gentle people out there.
Best wishes.