Your question does not make sense. Please elaborate ... are you possibly talking about the "oxygen window"?
A mixture of helium and oxygen is commercially known as heliox and generally refers to a mixture of 21% O2 (the same as air) and 79% He, although other combinations are available.
none that i know of. the u.s. navy probably does technical diving in the area
no. oxygen and pressure is a lethal combination... 400ft has just to much pressure..you will need nitrous to dive that deep... which is very dangerous.AdditionYes, technical divers can dive to 400 feet. But they do not breathe pure oxygen (or nitrous on the bottom). They breath a combination of helium, oxygen and nitrogen known as trimix.
With scuba diving, you are diving with an oxygen tank on your back and a regulator in your mouth. For SNUBA, there isn't an oxygen pack on your back, instead your oxygen supply is a long hose attached to a raft on the surface of the water.
Professional Diving is a type of diving where the divers are paid for their work. Recreational diving or sport diving is a type of diving that uses SCUBA equipment for the purpose of leisure and enjoyment. Military, navy, rescue and police diving courses need to be taken per your division or location. Technical and scientific diving is mainly for research and exploration.
Some credible technical websites would be Radio shack's technical support website. Ibm also has a technical support website that will walk you through a technical problem step by step.
buhb
no
Oxygen is not known as helium. But a mixture of oxygen and helium is used in the oxygen cylinder for underwater diving.
free diving diving without oxygen masks and stuff
"Global Underwater Explorers" - GUE is a scuba diving organization based in High Springs, Florida. It provides education on recreational, technical and cave diving.
Oxygen (Step 1:takes in carbon dioxide. Step 2:releases oxygen)