In some of my meditations I refer to the three energy centers that are just below the umbilicus.
I am also a Doctor of Oriental Medicine and these are terms used when referring to the internal energetic channels in the body regarding Chinese Medicine. Let me know if you have any further questions. Books that have information about this material would be in Chinese Acupuncture Literature.
This is a book that talks about the Ming Men – Yoga Alchemy by Larry Johnson
I have pasted below a few links with the definitions of these terms.
Dantien – http://en.wikipedia.org/wiki/Dantian
Ming Men – http://www.kheper.net/topics/chakras/Door_of_Life.htm
More info – http://www.itmonline.org/5organs/kidney.htm
The woo qi is the energy that is in the center between the Ming Men and Dantien.