The catalytic performance of two oxides coated anodes （OCSs） meshes and one OCA plate was investigated in a zinc electrowinning electrolyte at 38 ℃. Their electrochemical behaviors were compared with that of a conv...The catalytic performance of two oxides coated anodes （OCSs） meshes and one OCA plate was investigated in a zinc electrowinning electrolyte at 38 ℃. Their electrochemical behaviors were compared with that of a conventional Pb-0.7%Ag alloy anode. Electrochemical measurements such as cyclic voltammetric, galvanostatic, potentiodynamic, open-circuit potential （OCP） and in situ electrochemical noise measurements were considered. After 2 h of OCP test, the linear polarization shows that the corrosion current density of the Ti/（IrO2-Ta2O5） mesh electrode is the lowest （3.37μA/cm^2） among the three OCAs and shows excellent performance. Additionally, after 24 h of galvanostatic polarization at 50 mA/cm^2and 38 ℃, the Ti/MnO2mesh anode has the highest potential （1.799 V）, followed by the Ti/（IrO2-Ta2O5） plate （1.775 V） and Ti/（IrO2-Ta2O5） mesh （1.705 V） anodes. After 24 h of galvanostatic polarization followed by 16 h of decay, the linear polarization method confirms the sequence obtained after 2 h of OCP test, and the Ti/（IrO2-Ta2O5） mesh attains the lowest corrosion current density. The Ti/（IrO2-Ta2O5） mesh anode also shows better performance after 24 h of galvanostatic polarization with the overpotential lower than that of the conventional Pb-Ag anode by about 245 mV.展开更多
Mg-6%Al-5%Pb and Mg-6%Al-5%Pb-0.55%Zn-0.22%Mn(mass fraction) alloys were prepared by induction melting with the protection of argon.The corrosion behaviors of these alloys were studied by electrochemical measurements ...Mg-6%Al-5%Pb and Mg-6%Al-5%Pb-0.55%Zn-0.22%Mn(mass fraction) alloys were prepared by induction melting with the protection of argon.The corrosion behaviors of these alloys were studied by electrochemical measurements and immersion tests.The results show that at the corrosion onset of Mg-Al-Pb anode there is an incubation period that can be shortened with 0.55%Zn and 0.22%Mn additions in the magnesium matrix.The corrosion rate of Mg-Al-Pb anode is mainly determined by the incubation period.Short incubation period always leads to high corrosion rate while long incubation period leads to low corrosion rate.The corrosion rates based on the corrosion current density by the electrochemical measurements do not agree with the measurements evaluated from the evolved hydrogen volume.展开更多
Electrochemical measurement, quantum chemical method, and scanning electron microscopy （SEM） were performed to investigate the inhibitive effect of 2,3,5-triphenyl-2H-tetrazolium chloride （TTC） and 2,4,6-tri（2-py...Electrochemical measurement, quantum chemical method, and scanning electron microscopy （SEM） were performed to investigate the inhibitive effect of 2,3,5-triphenyl-2H-tetrazolium chloride （TTC） and 2,4,6-tri（2-pyridyl） -s-triazine（TPT） on the corrosion of mild steel in lmol.L^-1 HCl at room temperature. Impedance spectroscopy measurement showed that the polarization resistance increased and that double layer capacitance decreased with the increase in the inhibitive concentration, and the results of potentiodynamic polarization showed that the inhibitors suppressed both cathodic and anodic processes of steel corrosion without change in the mecha-nism. Higher the orbital density distribution strength of the lowest unoccupied molecular orbital, higher is the molecule dipole, and lower energy gap between the energy of the highest occupied molecular orbital and the energy of the lowest unoccupied molecular orbital resulted in higher inhibitory efficiency. The results of SEM analysis showed that the metal-was protected from aggressive corrosion by the addition of TTC and TPT.展开更多
The effects of trace element Fe on the corrosion behavior of AZ80 magnesium alloy were investigated by salt spray test and electrochemical measurements.The results show that the corrosion rate decreases with decreasin...The effects of trace element Fe on the corrosion behavior of AZ80 magnesium alloy were investigated by salt spray test and electrochemical measurements.The results show that the corrosion rate decreases with decreasing the trace element Fe content in an approximately linear relation even though the amount of trace element Fe reduces to 0.000 2%(mass fraction).The electrochemical measurements show that the corrosion potential(φcorr)of the alloy with lower trace element Fe content shifts to less negative value.It is suggested that the control trace element by purification is an effective way to enhance the corrosion resistance of AZ80 magnesium alloy.展开更多
Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and ID NMR spe...Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and ID NMR spectroscopic data, their structures were determined as： stigmast-4-en-3-one （Ⅰ）, cholest-4-en-3-one （Ⅱ）, cholesterol （m）, uracil （Ⅳ）, uridine （V）, adenosine （Ⅵ）, succinic acid （Ⅶ）, and 5-hydroxy-4-methyl-5-pentyl-2,5-dihydro-furan-2-on （Ⅷ）. All of them were obtained from this species for the first time. Cytotoxicity of these compounds was screened using standard MTT method, but all the compounds were inactive （IC50 〉 10 μg/ml）.展开更多
Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using X-ray diffractometry （XRD）, scanning electron microscopy （SEM） glucose as carbon source. The samples were characterized by and electrochemical measurements....Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using X-ray diffractometry （XRD）, scanning electron microscopy （SEM） glucose as carbon source. The samples were characterized by and electrochemical measurements. All Li2Fe0.9Mn0.1SiO4/C composites are of the similar crystal structure. With increasing the carbon content in the range of 5%-20% （mass fraction）, the diffraction peaks in XRD patterns broaden and the particle sizes and the tap density of samples decrease. The Li2Fe0.9Mn0.1SiO4/C composites with carbon content of 14.12% show excellent electrochemical performances with an initial discharge capacity of 154.7 mA.h/g at C/16 rate, and the capacity retention remains 92.2% after 30 cycles.展开更多
Proton exchange membrane fuel cell (PEMFC) stack temperature and cathode stoichiometric oxygen are very important control parameters. The performance and lifespan of PEMFC stack are greatly dependent on the parameters...Proton exchange membrane fuel cell (PEMFC) stack temperature and cathode stoichiometric oxygen are very important control parameters. The performance and lifespan of PEMFC stack are greatly dependent on the parameters. So, in order to improve the performance index, tight control of two parameters within a given range and reducing their fluctuation are indispensable. However, control-oriented models and control strategies are very weak junctures in the PEMFC development. A predictive control algorithm was presented based on their model established by input-output data and operating experiences. It adjusts the operating temperature to 80 ℃. At the same time, the optimized region of stoichiometric oxygen is kept between 1.8?2.2. Furthermore, the control algorithm adjusts the variants quickly to the destination value and makes the fluctuation of the variants the least. According to the test results, compared with traditional fuzzy and PID controllers, the designed controller shows much better performance.展开更多
The LiMoS： anode material for lithium ion rechargeable batteries were synthesized by a hydrothermal method at 150 ℃. According to our measurements with X-ray diffraction, LiMoS2 was amorphous structure. Electrochemi...The LiMoS： anode material for lithium ion rechargeable batteries were synthesized by a hydrothermal method at 150 ℃. According to our measurements with X-ray diffraction, LiMoS2 was amorphous structure. Electrochemical measurements results showed that LiMoS2 exhibited large lithium storage capacities.展开更多
The first modem survey of the Dead Sea was performed by the Geological Survey of Israel in 1959-1960, and the report published remains the baseline study for our understanding of the physical and chemical properties o...The first modem survey of the Dead Sea was performed by the Geological Survey of Israel in 1959-1960, and the report published remains the baseline study for our understanding of the physical and chemical properties of the lake. At the time the Dead Sea was a meromictic lake with a strong salinity gradient separating the deep waters （〉40 m depth） from the less saline surface waters. A few results of analyses of deeper water samples collected in the 1930s were reported, but overall we have very little information about the structure of the lake＇s water column before the 1959-1960 survey. However, it is little known that data on the physical and the chemical structure of the Dead Sea water column were obtained already in the middle of the 19~ century, and the information collected then is highly relevant for the reconstruction of the limnological properties of the lake in earlier times. The expedition of Lieutenant William Lynch （U.S. Navy） in 1848 reported the presence of a temperature minimum at a depth of-18 m, and also retrieved a water sample collected close to the bottom for chemical analysis. In 1864, the French Dead Sea exploration by the Duc de Luynes and his crew yielded detailed density and salinity profiles for a number of sampling stations. The results of these pioneering studies are discussed here, as well as the sampling equipment and measuring instruments used by the 1848 and the 1864 expeditions.展开更多
A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin ...A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin （EQ） and tert-butylhydroquinone （TBHQ） contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error （ANWE） algorithm was used to deal with EEM data. Via the introduced ＂second-order advantage＂, the individual con- centrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows： EQ, from 4.58 to 20.6 p.g mL-1 in plasma and from 6.87 to 20.6 gg mL-1 in urine; TBHQ, from 4.49 to 20.2 ~tg mL-1 in plasma and from 6.73 to 22.4 I.tg mL-l in urine. The recoveries from spiked bi- ological fluid samples were in the ranges of 92.8%-106.2% for EQ and 94.6%-107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.展开更多
基金Project(RDCPJ 428402)supported by the Natural Sciences and Engineering Research Council of Canada
文摘The catalytic performance of two oxides coated anodes （OCSs） meshes and one OCA plate was investigated in a zinc electrowinning electrolyte at 38 ℃. Their electrochemical behaviors were compared with that of a conventional Pb-0.7%Ag alloy anode. Electrochemical measurements such as cyclic voltammetric, galvanostatic, potentiodynamic, open-circuit potential （OCP） and in situ electrochemical noise measurements were considered. After 2 h of OCP test, the linear polarization shows that the corrosion current density of the Ti/（IrO2-Ta2O5） mesh electrode is the lowest （3.37μA/cm^2） among the three OCAs and shows excellent performance. Additionally, after 24 h of galvanostatic polarization at 50 mA/cm^2and 38 ℃, the Ti/MnO2mesh anode has the highest potential （1.799 V）, followed by the Ti/（IrO2-Ta2O5） plate （1.775 V） and Ti/（IrO2-Ta2O5） mesh （1.705 V） anodes. After 24 h of galvanostatic polarization followed by 16 h of decay, the linear polarization method confirms the sequence obtained after 2 h of OCP test, and the Ti/（IrO2-Ta2O5） mesh attains the lowest corrosion current density. The Ti/（IrO2-Ta2O5） mesh anode also shows better performance after 24 h of galvanostatic polarization with the overpotential lower than that of the conventional Pb-Ag anode by about 245 mV.
基金Project(JPPT-115-168) supported by National Key Science and Technological Project of China
文摘Mg-6%Al-5%Pb and Mg-6%Al-5%Pb-0.55%Zn-0.22%Mn(mass fraction) alloys were prepared by induction melting with the protection of argon.The corrosion behaviors of these alloys were studied by electrochemical measurements and immersion tests.The results show that at the corrosion onset of Mg-Al-Pb anode there is an incubation period that can be shortened with 0.55%Zn and 0.22%Mn additions in the magnesium matrix.The corrosion rate of Mg-Al-Pb anode is mainly determined by the incubation period.Short incubation period always leads to high corrosion rate while long incubation period leads to low corrosion rate.The corrosion rates based on the corrosion current density by the electrochemical measurements do not agree with the measurements evaluated from the evolved hydrogen volume.
基金Supported by Key Projects of National Knowledge Innovation Program at Chinese Academy of Sciences (Kzcx2-yw-210-03).
文摘Electrochemical measurement, quantum chemical method, and scanning electron microscopy （SEM） were performed to investigate the inhibitive effect of 2,3,5-triphenyl-2H-tetrazolium chloride （TTC） and 2,4,6-tri（2-pyridyl） -s-triazine（TPT） on the corrosion of mild steel in lmol.L^-1 HCl at room temperature. Impedance spectroscopy measurement showed that the polarization resistance increased and that double layer capacitance decreased with the increase in the inhibitive concentration, and the results of potentiodynamic polarization showed that the inhibitors suppressed both cathodic and anodic processes of steel corrosion without change in the mecha-nism. Higher the orbital density distribution strength of the lowest unoccupied molecular orbital, higher is the molecule dipole, and lower energy gap between the energy of the highest occupied molecular orbital and the energy of the lowest unoccupied molecular orbital resulted in higher inhibitory efficiency. The results of SEM analysis showed that the metal-was protected from aggressive corrosion by the addition of TTC and TPT.
基金Project(2007CB613705)supported by the National Basic Research Program of China
文摘The effects of trace element Fe on the corrosion behavior of AZ80 magnesium alloy were investigated by salt spray test and electrochemical measurements.The results show that the corrosion rate decreases with decreasing the trace element Fe content in an approximately linear relation even though the amount of trace element Fe reduces to 0.000 2%(mass fraction).The electrochemical measurements show that the corrosion potential(φcorr)of the alloy with lower trace element Fe content shifts to less negative value.It is suggested that the control trace element by purification is an effective way to enhance the corrosion resistance of AZ80 magnesium alloy.
基金the Project NNSF of China (No. 30530080 and 20432030)the New Century Excellent Talent Supporting Program of Chinese Ministry of Education
文摘Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and ID NMR spectroscopic data, their structures were determined as： stigmast-4-en-3-one （Ⅰ）, cholest-4-en-3-one （Ⅱ）, cholesterol （m）, uracil （Ⅳ）, uridine （V）, adenosine （Ⅵ）, succinic acid （Ⅶ）, and 5-hydroxy-4-methyl-5-pentyl-2,5-dihydro-furan-2-on （Ⅷ）. All of them were obtained from this species for the first time. Cytotoxicity of these compounds was screened using standard MTT method, but all the compounds were inactive （IC50 〉 10 μg/ml）.
基金Project(50302016) supported by the National Natural Science Foundation of China
文摘Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using X-ray diffractometry （XRD）, scanning electron microscopy （SEM） glucose as carbon source. The samples were characterized by and electrochemical measurements. All Li2Fe0.9Mn0.1SiO4/C composites are of the similar crystal structure. With increasing the carbon content in the range of 5%-20% （mass fraction）, the diffraction peaks in XRD patterns broaden and the particle sizes and the tap density of samples decrease. The Li2Fe0.9Mn0.1SiO4/C composites with carbon content of 14.12% show excellent electrochemical performances with an initial discharge capacity of 154.7 mA.h/g at C/16 rate, and the capacity retention remains 92.2% after 30 cycles.
基金Project (2003AA517020) supported by the National High-Tech Research and Development Program of China
文摘Proton exchange membrane fuel cell (PEMFC) stack temperature and cathode stoichiometric oxygen are very important control parameters. The performance and lifespan of PEMFC stack are greatly dependent on the parameters. So, in order to improve the performance index, tight control of two parameters within a given range and reducing their fluctuation are indispensable. However, control-oriented models and control strategies are very weak junctures in the PEMFC development. A predictive control algorithm was presented based on their model established by input-output data and operating experiences. It adjusts the operating temperature to 80 ℃. At the same time, the optimized region of stoichiometric oxygen is kept between 1.8?2.2. Furthermore, the control algorithm adjusts the variants quickly to the destination value and makes the fluctuation of the variants the least. According to the test results, compared with traditional fuzzy and PID controllers, the designed controller shows much better performance.
文摘The LiMoS： anode material for lithium ion rechargeable batteries were synthesized by a hydrothermal method at 150 ℃. According to our measurements with X-ray diffraction, LiMoS2 was amorphous structure. Electrochemical measurements results showed that LiMoS2 exhibited large lithium storage capacities.
文摘The first modem survey of the Dead Sea was performed by the Geological Survey of Israel in 1959-1960, and the report published remains the baseline study for our understanding of the physical and chemical properties of the lake. At the time the Dead Sea was a meromictic lake with a strong salinity gradient separating the deep waters （〉40 m depth） from the less saline surface waters. A few results of analyses of deeper water samples collected in the 1930s were reported, but overall we have very little information about the structure of the lake＇s water column before the 1959-1960 survey. However, it is little known that data on the physical and the chemical structure of the Dead Sea water column were obtained already in the middle of the 19~ century, and the information collected then is highly relevant for the reconstruction of the limnological properties of the lake in earlier times. The expedition of Lieutenant William Lynch （U.S. Navy） in 1848 reported the presence of a temperature minimum at a depth of-18 m, and also retrieved a water sample collected close to the bottom for chemical analysis. In 1864, the French Dead Sea exploration by the Duc de Luynes and his crew yielded detailed density and salinity profiles for a number of sampling stations. The results of these pioneering studies are discussed here, as well as the sampling equipment and measuring instruments used by the 1848 and the 1864 expeditions.
基金the National Natural Science Foundation of China (21175041)the National Basic Research Program(2012CB910602) for financial support
文摘A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin （EQ） and tert-butylhydroquinone （TBHQ） contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error （ANWE） algorithm was used to deal with EEM data. Via the introduced ＂second-order advantage＂, the individual con- centrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows： EQ, from 4.58 to 20.6 p.g mL-1 in plasma and from 6.87 to 20.6 gg mL-1 in urine; TBHQ, from 4.49 to 20.2 ~tg mL-1 in plasma and from 6.73 to 22.4 I.tg mL-l in urine. The recoveries from spiked bi- ological fluid samples were in the ranges of 92.8%-106.2% for EQ and 94.6%-107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.
