For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media wa...For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media was selected on the basis of the Pourbaix potential-pH diagram, which provides informations on the predominance of Zr<sup>(IV) </sup> ion and Zr in aqueous media. In aqueous media, analyzes were first carried out in acidic media then in basic media. Studies have thus revealed that the acidic environment is not favourable for the electrochemical analysis of zirconium. Voltammograms obtained in an acidic environment show no zirconium detection signal;this is due to the strong presence of H<sup>+</sup> ions in the solution. We have also observed in acidic media the phenomenon of passivation of the electrode surface. In aqueous alkaline media (pH = 13), we have drawn in reduction several Intensity-Potential curves by fixingsome technical parameterslike scanning speed, rotation speed of the electrode. The obtained voltammograms show cathodic waves, starting from -1.5 V/DHW and attributed to the reduction of Zr<sup> (IV) </sup> to Zr (0). The last phase of this study focused on the electrochemical analysis of zirconium in an organic media. In this media, several intensity-potential curves were plotted in reduction and in cyclic voltammetry with various parameters. Through several reduction analysis, the Zr<sup> (IV) </sup> was reduced to Zr (0) to the potential of -1.5 V/DHW. The electrochemical analysis of zirconium in organic media seems globally easier to achieve thanks to its large solvent window (i.e. dimethylformamide (DMF) solvent window > 6 V).展开更多
Effects of flaky rare earth oxide additives including Er2O3,Tm2O3,and Yb2O3,Lu2O3 on high temperature and high rate discharge performance of nickel electrodes were investigated.The discharge efficiency at 0.2C reached...Effects of flaky rare earth oxide additives including Er2O3,Tm2O3,and Yb2O3,Lu2O3 on high temperature and high rate discharge performance of nickel electrodes were investigated.The discharge efficiency at 0.2C reached 96% at 60 oC for electrodes with 1 at.% flaky rare earth oxides.The high rate discharge performance for electrodes with flaky rare earth oxides were improved significantly,for example,discharge efficiency at 5C improved from 50% to 70%.The results showed that the end charging potential of the nickel electrodes with flaky rare earth oxides were higher than that without rare earth oxide additives,but lower than that with normal rare earth oxide additives.The CVs experimental results suggested that flaky rare earth oxides increased the oxygen evolution potential and improved the reversibility of nickel electrodes.展开更多
Electrochemical behavior of hypophosphite was studied with cyclic voltammogram in acidic solution(pH = 4.6) at 80℃. Two anodic peaks were observed on gold electrode at - 0.44V and - 0.59 V (SCE),respectively, and no ...Electrochemical behavior of hypophosphite was studied with cyclic voltammogram in acidic solution(pH = 4.6) at 80℃. Two anodic peaks were observed on gold electrode at - 0.44V and - 0.59 V (SCE),respectively, and no corresponding cathodic peaks were obtained. The one at - 0.44 V wits ascribed to the oxidation oftautomeric form of hypophosphite, the other at - 0.59 V was due to the oxidation of absorbed form of hypophosphite. The two oxidation reactions were believed to be the electron source of nickel ion reduction in electrolessnickel processes.展开更多
A novel organic disulfide, N,N′ dithiobis(3 nitroaniline)(1) was prepared by the reaction of 3 nitroaniline with sulfur monochloride in chloroform. Compound 1 was reduced by zinc powder to give N,N′\|dithiobis(1,3 p...A novel organic disulfide, N,N′ dithiobis(3 nitroaniline)(1) was prepared by the reaction of 3 nitroaniline with sulfur monochloride in chloroform. Compound 1 was reduced by zinc powder to give N,N′\|dithiobis(1,3 phenylenediamine)(2). Poly N,N′ dithiobis(1,3 phenylenediamine)(3) was prepared by electrochemical polymerization of compound 2 and its basic electrochemical behavior is discussed.展开更多
The anti-tumor activity of Trichosanthin (TCS) has been frequently reported in recent years. In our experiments, electrochemical methods were applied to delect the effects of TCS on human leukemia cells U937. 50μg/ml...The anti-tumor activity of Trichosanthin (TCS) has been frequently reported in recent years. In our experiments, electrochemical methods were applied to delect the effects of TCS on human leukemia cells U937. 50μg/ml TCS treatment for 40 hours can cause irreversible negative effects on the viability of U937 cells. This effect Iargely depends on the concentration of TCS and the time period of treatment.展开更多
A low component count, microcontroller-based potentiostat circuit was developed through the use of operational amplifiers arranged in different feedback configurations. This was developed to alleviate the cost burden ...A low component count, microcontroller-based potentiostat circuit was developed through the use of operational amplifiers arranged in different feedback configurations. This was developed to alleviate the cost burden of equipment procurement in low-cost and budget applications. Simplicity was achieved in the design by the use of the microcontroller’s native functionalities and a low-cost R/2R resistor ladder digital-to-analogue converter. The potentiostat was used to investigate the Ni2+/Ni(s) redox couple in a 3-electrode cell with a silver/silver chloride reference electrode and graphite counter and working electrodes. Linear sweep voltammograms were ob-tained at scan rates of 10, 20, 30 and 40 mV/s. The analysis of the peak current versus (scan rate)1/2 plot indicated that the Ni2+/Ni(s) reduction, though conforming to the Randles-Sevcik equation, was a non-reversible redox reaction.展开更多
Vanadium oxide nanostructures were synthesized using NTP as a carrier through soft-chemical method. The influence of calcination temperature on the phase and morphology of obtained pristine product were characterized ...Vanadium oxide nanostructures were synthesized using NTP as a carrier through soft-chemical method. The influence of calcination temperature on the phase and morphology of obtained pristine product were characterized using X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). Cyclic voltammogram studies were conducted to examine the electrochemical performance of cathodes made of vanadium oxide nanostructures. X-ray diffraction results show that, the particle size of the nanomaterials is increases with the increasing of calcination temperature.展开更多
The electrochemical reductions and oxidations of tetraphenylporphyrin (TPP) and vanadyl por-phyrin (TPP-VO) were investigated in dimethylformamide at platinum,glass carbon and microdisk electrodes.A new eleetrode reac...The electrochemical reductions and oxidations of tetraphenylporphyrin (TPP) and vanadyl por-phyrin (TPP-VO) were investigated in dimethylformamide at platinum,glass carbon and microdisk electrodes.A new eleetrode reaction mechanism of TPP and TPP-VO is proposed.The kinetic parameters have also been determined.In addition,the theory of molecular hybrid orbitals is used to explain the reduction and oxidation regularity of the transition metal展开更多
In this paper,we report a method for obtaining a visual voltammogram at a linear array of closed wireless bipolar electrodes(BPEs).This advancement is significant,because the visual voltammogram captures the entire cu...In this paper,we report a method for obtaining a visual voltammogram at a linear array of closed wireless bipolar electrodes(BPEs).This advancement is significant,because the visual voltammogram captures the entire current-potential(i-E)relationship of a faradaic reaction in one image and is continuously generated over time.Therefore,we anticipate that this method will allow monitoring in redox systems that change over time.Further,the use of a linear array of BPEs eliminates the need to use a potentiostat and can be carried out with a simple DC power supply.Our experimental and numerical results demonstrate that the visual voltammogram is similar to a linear sweep voltammogram and therefore,information about the faradaic process can be extracted from the wave position,height,and shape.展开更多
文摘For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media was selected on the basis of the Pourbaix potential-pH diagram, which provides informations on the predominance of Zr<sup>(IV) </sup> ion and Zr in aqueous media. In aqueous media, analyzes were first carried out in acidic media then in basic media. Studies have thus revealed that the acidic environment is not favourable for the electrochemical analysis of zirconium. Voltammograms obtained in an acidic environment show no zirconium detection signal;this is due to the strong presence of H<sup>+</sup> ions in the solution. We have also observed in acidic media the phenomenon of passivation of the electrode surface. In aqueous alkaline media (pH = 13), we have drawn in reduction several Intensity-Potential curves by fixingsome technical parameterslike scanning speed, rotation speed of the electrode. The obtained voltammograms show cathodic waves, starting from -1.5 V/DHW and attributed to the reduction of Zr<sup> (IV) </sup> to Zr (0). The last phase of this study focused on the electrochemical analysis of zirconium in an organic media. In this media, several intensity-potential curves were plotted in reduction and in cyclic voltammetry with various parameters. Through several reduction analysis, the Zr<sup> (IV) </sup> was reduced to Zr (0) to the potential of -1.5 V/DHW. The electrochemical analysis of zirconium in organic media seems globally easier to achieve thanks to its large solvent window (i.e. dimethylformamide (DMF) solvent window > 6 V).
基金supported by the 863 National Research and Development Project Foundation of China (2006AA11A151)
文摘Effects of flaky rare earth oxide additives including Er2O3,Tm2O3,and Yb2O3,Lu2O3 on high temperature and high rate discharge performance of nickel electrodes were investigated.The discharge efficiency at 0.2C reached 96% at 60 oC for electrodes with 1 at.% flaky rare earth oxides.The high rate discharge performance for electrodes with flaky rare earth oxides were improved significantly,for example,discharge efficiency at 5C improved from 50% to 70%.The results showed that the end charging potential of the nickel electrodes with flaky rare earth oxides were higher than that without rare earth oxide additives,but lower than that with normal rare earth oxide additives.The CVs experimental results suggested that flaky rare earth oxides increased the oxygen evolution potential and improved the reversibility of nickel electrodes.
文摘Electrochemical behavior of hypophosphite was studied with cyclic voltammogram in acidic solution(pH = 4.6) at 80℃. Two anodic peaks were observed on gold electrode at - 0.44V and - 0.59 V (SCE),respectively, and no corresponding cathodic peaks were obtained. The one at - 0.44 V wits ascribed to the oxidation oftautomeric form of hypophosphite, the other at - 0.59 V was due to the oxidation of absorbed form of hypophosphite. The two oxidation reactions were believed to be the electron source of nickel ion reduction in electrolessnickel processes.
文摘A novel organic disulfide, N,N′ dithiobis(3 nitroaniline)(1) was prepared by the reaction of 3 nitroaniline with sulfur monochloride in chloroform. Compound 1 was reduced by zinc powder to give N,N′\|dithiobis(1,3 phenylenediamine)(2). Poly N,N′ dithiobis(1,3 phenylenediamine)(3) was prepared by electrochemical polymerization of compound 2 and its basic electrochemical behavior is discussed.
文摘The anti-tumor activity of Trichosanthin (TCS) has been frequently reported in recent years. In our experiments, electrochemical methods were applied to delect the effects of TCS on human leukemia cells U937. 50μg/ml TCS treatment for 40 hours can cause irreversible negative effects on the viability of U937 cells. This effect Iargely depends on the concentration of TCS and the time period of treatment.
文摘A low component count, microcontroller-based potentiostat circuit was developed through the use of operational amplifiers arranged in different feedback configurations. This was developed to alleviate the cost burden of equipment procurement in low-cost and budget applications. Simplicity was achieved in the design by the use of the microcontroller’s native functionalities and a low-cost R/2R resistor ladder digital-to-analogue converter. The potentiostat was used to investigate the Ni2+/Ni(s) redox couple in a 3-electrode cell with a silver/silver chloride reference electrode and graphite counter and working electrodes. Linear sweep voltammograms were ob-tained at scan rates of 10, 20, 30 and 40 mV/s. The analysis of the peak current versus (scan rate)1/2 plot indicated that the Ni2+/Ni(s) reduction, though conforming to the Randles-Sevcik equation, was a non-reversible redox reaction.
基金One of the authors(VS Reddy Channu)thank the Alex-ander von Humboldt Foundation for a fellow-shipThis work is partially supported by U.S-DOD-ARO-HBCU/MI.
文摘Vanadium oxide nanostructures were synthesized using NTP as a carrier through soft-chemical method. The influence of calcination temperature on the phase and morphology of obtained pristine product were characterized using X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). Cyclic voltammogram studies were conducted to examine the electrochemical performance of cathodes made of vanadium oxide nanostructures. X-ray diffraction results show that, the particle size of the nanomaterials is increases with the increasing of calcination temperature.
基金Project supported by the National Natural Science Foundation of Chinathe State Key Laboratory of Rare Earth Materials ChemistryApphcations
文摘The electrochemical reductions and oxidations of tetraphenylporphyrin (TPP) and vanadyl por-phyrin (TPP-VO) were investigated in dimethylformamide at platinum,glass carbon and microdisk electrodes.A new eleetrode reaction mechanism of TPP and TPP-VO is proposed.The kinetic parameters have also been determined.In addition,the theory of molecular hybrid orbitals is used to explain the reduction and oxidation regularity of the transition metal
文摘In this paper,we report a method for obtaining a visual voltammogram at a linear array of closed wireless bipolar electrodes(BPEs).This advancement is significant,because the visual voltammogram captures the entire current-potential(i-E)relationship of a faradaic reaction in one image and is continuously generated over time.Therefore,we anticipate that this method will allow monitoring in redox systems that change over time.Further,the use of a linear array of BPEs eliminates the need to use a potentiostat and can be carried out with a simple DC power supply.Our experimental and numerical results demonstrate that the visual voltammogram is similar to a linear sweep voltammogram and therefore,information about the faradaic process can be extracted from the wave position,height,and shape.
