12.Preoxygenation replaces the primarily nitrogenous mixture of ambient air, which constitutes the patient's functional residual capacity, with oxygen.
15.In this paper, the protection measures of carbohydrate during pulp TCF bleaching, such as oxygen, ozone, peroxide, peracid and photochemistry reaction of bleaching, were respectively.
16.Introduce the general idea: human body need all kinds of nourishment during the life(such as water, inorganic acid, protein, glycolipin, microbian mineral, oxygen),blood cycle for digestion.