The effects of electrolyte (different types and different ion strength) on critical concentration (C *) of the chitosan and N alkyl chitosan liquid crystalline in formic acid solutions were studied.

Critical concentration(c  )of the samples were measured by polar optical microscopy(POM).

It was showed that,when the concentration of dosed NaCl solution reached the critical salt concentration,there would generate the phenomenon of particles releasing in sand column;in mixed salt solution,the existence of molar percent of Ca2+ would inhibit the .

The results indicate that critical salt concentration and critical flow rate exit on the saltwater-freshwater interface.

With horizontal seepage experiments,this paper analyzes the critical salt concentrations(CSC)of the different cations,by examining such solutions as NaCl,KCl,LiCl,NH_4Cl,CaCl_2 and MgCl_2,which can cause the particle release of water sensitivity of porous media.

The research on the critical oxygen concentration of combustive gas is limited to the elementary gas.

On the basis of the measurea critical oxygen concentration,this paper estab-lishes a model for evaluating the oxygen concentration C(r)in mycelial pellets.

The paper experimentally studied the explosive limit and the critical oxygen concentration of several kinds of gases that are found in the mine.

It is shown that a limiting carbon concentration in the vicinity of the growing ferrite nuclei is invariable with the variations of temperature and cooling rate,while increases linearly with the Nb content .