The inhibition effect of dimethylethanolamine（DMEA） and its composite with carboxylic acid was studied with the electrochemical tests. The experimental results indicate that DMEA is not a good inhibitor but the comp...The inhibition effect of dimethylethanolamine（DMEA） and its composite with carboxylic acid was studied with the electrochemical tests. The experimental results indicate that DMEA is not a good inhibitor but the composite of DMEA with caprylic acid exhibits excellent inhibiting efficiency. The synergic mechanism of the organic corrosion inhibitors（OCIs） was studied with quantum chemical calculations. It is found that the DMEA forms a quaternary ammonium salt with the proton in carboxylic acid, and a cyclic complex formed between the salt and Fe may be responsible for the enhancement of inhibiting efficiency. The possible hydrogen bond formed between DMEA and carboxylic acid is not enough for the inhibiting effect. This work is helpful to proposing theoretical interpretation as well as developing a functional organic inhibitor to improve the durability of reinforced concrete contaminated with chloride.展开更多
Objective:To provide a kinetic model(s) and reveal the mechanism of thymoquinone and Poloxin blocking an emerging anti-cancer target,human Polo-like kinase 1(hPlk1) Polo-box domain(PBD).Methods:The binding kinetics wa...Objective:To provide a kinetic model(s) and reveal the mechanism of thymoquinone and Poloxin blocking an emerging anti-cancer target,human Polo-like kinase 1(hPlk1) Polo-box domain(PBD).Methods:The binding kinetics was determined by using a fluorescence polarization based assay.The putative mechanism was examined with a competition test.Results:Thymoquinone follows a one-step binding with an association rate constant(k1) of 6.635×103 L·mol-1·min-1.Poloxin fit a two-step binding with a dissociation constant(Ki) of 118 μmol/L for the intermediate complex and its isomerization rate(k4) of 0.131 5 min-1 to form an irreversible adduct.No significant dissociation was observed for either ligand up to 13 h.The inhibitors responded insignificantly to the presence of Michael donors as hPlk1-PBD competitors.Conclusion:Thymoquinone and Poloxin are slow-tight ligands to the hPlk1-PBD with kinetic models distinct from each other.Michael addition as the mechanism is excluded.展开更多
The effect of Co complexes with a Schiff base ligand on the electrochemical corrosion behavior of 316 L SS in 0.1 M H<sub>2</sub>SO<sub>4</sub> at 25℃ has been investigated at various inhibito...The effect of Co complexes with a Schiff base ligand on the electrochemical corrosion behavior of 316 L SS in 0.1 M H<sub>2</sub>SO<sub>4</sub> at 25℃ has been investigated at various inhibitor concentration using electrochemical techniques (impedance spectroscopy (EIS), polarization curves). Corrosion measurements indicate that Co complex act as moderately inhibitors. Results revealed that increasing the concentration of Co complex increases the corresponding IE% values till 100 ppm. Co complex acts as mixed type inhibitors with predominant effect on the anodic dissolution of iron. Adsorption studies showed that the process follows Langmuir adsorption isotherm.展开更多
Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO<sub>3</sub> and 1 M H<sub>2</sub>SO<sub>4</sub> solutions was investigated by potentiodynamic polarization, Scann...Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO<sub>3</sub> and 1 M H<sub>2</sub>SO<sub>4</sub> solutions was investigated by potentiodynamic polarization, Scanning electron microscopy (SEM) and Foutier transform infrared (FT-IR). Inhibition efficiency increased with the increase of the concentration of the gel. The optimal concentration of the gel gives maximum inhibition efficiency of 77.4% and 70.3% in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Polarization plots shows that, the gel works as a mixed type inhibitor altering both cathodic and anodic reaction. SEM proves the uniform and pitting corrosion at the surface of Mild steel in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Using FT-IR potential function groups from pure gel and some stretch shift was observed from corrosion product and some stretch shift from corrosion products was observed.展开更多
基金Funded by the National Natural Science Foundation of China(No.51278443)the Shandong Province Natural Science Foundation(ZR2011EEM006)
文摘The inhibition effect of dimethylethanolamine（DMEA） and its composite with carboxylic acid was studied with the electrochemical tests. The experimental results indicate that DMEA is not a good inhibitor but the composite of DMEA with caprylic acid exhibits excellent inhibiting efficiency. The synergic mechanism of the organic corrosion inhibitors（OCIs） was studied with quantum chemical calculations. It is found that the DMEA forms a quaternary ammonium salt with the proton in carboxylic acid, and a cyclic complex formed between the salt and Fe may be responsible for the enhancement of inhibiting efficiency. The possible hydrogen bond formed between DMEA and carboxylic acid is not enough for the inhibiting effect. This work is helpful to proposing theoretical interpretation as well as developing a functional organic inhibitor to improve the durability of reinforced concrete contaminated with chloride.
基金a co-sponsored graduate research project by China Pharmaceutical University and Shanghai Medicilon Inc
文摘Objective:To provide a kinetic model(s) and reveal the mechanism of thymoquinone and Poloxin blocking an emerging anti-cancer target,human Polo-like kinase 1(hPlk1) Polo-box domain(PBD).Methods:The binding kinetics was determined by using a fluorescence polarization based assay.The putative mechanism was examined with a competition test.Results:Thymoquinone follows a one-step binding with an association rate constant(k1) of 6.635×103 L·mol-1·min-1.Poloxin fit a two-step binding with a dissociation constant(Ki) of 118 μmol/L for the intermediate complex and its isomerization rate(k4) of 0.131 5 min-1 to form an irreversible adduct.No significant dissociation was observed for either ligand up to 13 h.The inhibitors responded insignificantly to the presence of Michael donors as hPlk1-PBD competitors.Conclusion:Thymoquinone and Poloxin are slow-tight ligands to the hPlk1-PBD with kinetic models distinct from each other.Michael addition as the mechanism is excluded.
文摘The effect of Co complexes with a Schiff base ligand on the electrochemical corrosion behavior of 316 L SS in 0.1 M H<sub>2</sub>SO<sub>4</sub> at 25℃ has been investigated at various inhibitor concentration using electrochemical techniques (impedance spectroscopy (EIS), polarization curves). Corrosion measurements indicate that Co complex act as moderately inhibitors. Results revealed that increasing the concentration of Co complex increases the corresponding IE% values till 100 ppm. Co complex acts as mixed type inhibitors with predominant effect on the anodic dissolution of iron. Adsorption studies showed that the process follows Langmuir adsorption isotherm.
文摘Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO<sub>3</sub> and 1 M H<sub>2</sub>SO<sub>4</sub> solutions was investigated by potentiodynamic polarization, Scanning electron microscopy (SEM) and Foutier transform infrared (FT-IR). Inhibition efficiency increased with the increase of the concentration of the gel. The optimal concentration of the gel gives maximum inhibition efficiency of 77.4% and 70.3% in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Polarization plots shows that, the gel works as a mixed type inhibitor altering both cathodic and anodic reaction. SEM proves the uniform and pitting corrosion at the surface of Mild steel in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Using FT-IR potential function groups from pure gel and some stretch shift was observed from corrosion product and some stretch shift from corrosion products was observed.
