In an experiment at elevated temperatures, the noble gas He slowly permeates a 0.5 mm glass membrane. The partial pressure of He on one side of the membrane is pHe = 2 atm, and on the other side pHe = 0.6 atm. The solubility of He in the specific glass of the membrane is 10-5 mol/cm3 at a He pressure of pHe = 1 atm and the temperature at which the experiment is performed. The flux of He through the membrane is measured to be 10-8 mol/(cm2∙s).  

Assuming that the He diffusion coefficient, DHe, is independent of the He concentration in the membrane, calculate the value of DHe in units of 10-6 cm2/s.