Freshwater green algae, Chlorella, have heavy cell walls and their size usually exceeds the lower limits of limb size of herbivorous Daphnia (Cladocera). According to the optimal foraging theory, we speculated that Daphnia would graze more exposed and relatively large Clamydomonas rather than Chlorella, and this process would lead to small-sized Chlorella becoming a superior competitor in the presence of Daphnia. We used Daphnia magna, Clamydomonas sajao and Chlorella pyrenoidosa to test this hypothesis. Our grazing experiments showed that Daphnia preferred C. sajao to C. pyrenoidosa, regardless of the concentration and relative abundance of these two algae. The decrease in relative abundance of high-quality Clamydomonas in Clamydomonas-Chlorella assemblages did not diminish the grazing efficiency of Daphnia on this algal species, but increased selectivity of low-quality Chlorella. However, when the concentration of Clamydomonas was extremely high, the grazing of Daphnia on Clamydomonas decreased. In competition experiments, we observed that the presence of Clamydomonas restrained the growth potential of Chlorella; however, the introduction of herbivorous Daphnia into the competing environment weakened this influence and to some extent enhanced the growth ability of Chlorella. Moreover, we also observed that the intensity of herbivory, imposed by different densities of Daphnia, had an obvious influence on the competition outcome between Clamydomonas and Chlorella. At the highest intensity of herbivory (10 Daphnia), C. sajao was eliminated from the culture medium whereas C. pyrenoidosa could persist, but at low cell density.

The corrosion inhibition of N,N-diethylammonium O,O-di (3-methylphenyl) dithio-phosphate (NDOMD) for Q235 steel in HCl solution was studied by electrochemical measurements and weight loss measurements. And the effects of temperature, HCl concentration and immersion time were also studied. Polarization curves indicate the NDOMD is a mixed-type inhibitor which anodic plays a leading role. The studies of weight loss measurement show that the inhibition efficiency was up to 94.46% at the NDOMD concentration of 100 mg·L-1 in 1.0 mol.L-1 HCl solution at 30°C. The adsorption of NDOMD on Q235 steel surface obeys the Langmuir isotherm.

The corrosion inhibition of S-benzyl-O,O'-dibenzyldithiophosphate (BBP) for carbon steel in hydrochloric acid solution was studied by electrochemical measurements and weight loss measurements. Polarization curves indicate BBP is a mixed-type inhibitor, and the effects of temperature, hydrochloric acid concentration and immersion time were also studied. The studies of weight loss measurement show that the inhibition efficiency was up to 97.39 % at the BBP concentration of 60 mg·L-1 in 1.0 M hydrochloric acid solution at 30°C. The adsorption of BBP on carbon steel surface obeys the Langmuir isotherm.

The corrosion inhibition of S-benzyl o-phenylenedioxydithiophosphate (BPOTP), for carbon steel in hydrochloric acid solution was studied by electrochemical measurements and weight loss measurements. Polarization curves indicate BPOTP is a mixed-type inhibitor, and the effects of temperature, hydrochloric acid concentration and immersion time were also studied. The studies of weight loss measurement show that the inhibition efficiency was up to 92.82 % at the BPOTP concentration of 40 mg·L-1 in 1.0 M hydrochloric acid solution at 30°C. The adsorption of BPOTP on carbon steel surface obeys the Langmuir isotherm.