Direct seawater electrolysis for hydrogen production has been regarded as a viable route to utilize surplus renewable energy and address the climate crisis.However,the harsh electrochemical environment of seawater,par...Direct seawater electrolysis for hydrogen production has been regarded as a viable route to utilize surplus renewable energy and address the climate crisis.However,the harsh electrochemical environment of seawater,particularly the presence of aggressive Cl^(-),has been proven to be prone to parasitic chloride ion oxidation and corrosion reactions,thus restricting seawater electrolyzer lifetime.Herein,hierarchical structure(Ni,Fe)O(OH)@NiCoS nanorod arrays(NAs)catalysts with heterointerfaces and localized oxygen vacancies were synthesized at nickel foam substrates via the combination of hydrothermal and annealing methods to boost seawater dissociation.The hiera rchical nanostructure of NiCoS NAs enhanced electrode charge transfer rate and active surface area to accelerate oxygen evolution reaction(OER)and generated sulfate gradient layers to repulsive aggressive Cl^(-).The fabricated heterostructure and vacancies of(Ni,Fe)O(OH)tuned catalyst electronic structure into an electrophilic state to enhance the binding affinity of hydroxyl intermediates and facilitate the structural transformation into amorphousγ-NiFeOOH for promoting OER.Furthermore,through operando electrochemistry techniques,we found that theγ-NiFeOOH possessing an unsaturated coordination environment and lattice-oxygen-participated OER mechanism can minimize electrode Cl^(-)corrosion enabled by stabilizing the adsorption of OH*intermediates,making it one of the best OER catalysts in the seawater medium reported to date.Consequently,these catalysts can deliver current densities of 100 and 500 mA cm-2for boosting OER at minimal overpotentials of 245and 316 mV,respectively,and thus prevent chloride ion oxidation simultaneously.Impressively,a highly stable anion exchange membrane(AEM)seawater electrolyzer based on the non-noble metal heterostructure electrodes reached a record low degradation rate under 100μV h-1at constant industrial current densities of 400 and 600 mA cm-2over 300 h,which exhibits a promising future for the nonprecious and stable AEMWE in the direct seawater electrolysis industry.展开更多
This paper advances the viewpoints and methods of the rapid sample product trial manufacture technique for developing water meter new products by CAD and simulation, computer virtual assembling and optimizing, rapid m...This paper advances the viewpoints and methods of the rapid sample product trial manufacture technique for developing water meter new products by CAD and simulation, computer virtual assembling and optimizing, rapid machining process and measurement etc. as the design and sample product trial manufacture process of water meter new products are long in product development period, and low in product development efficiency in the present time.展开更多
A direct analysis method combining an iminodiacetate extraction disk (IED) with graphite furnace atomic absorption spectrometry was developed for the determination of Co, Ni, Cu, Cd, Sn, Pb, and Bi at sub-ppb levels i...A direct analysis method combining an iminodiacetate extraction disk (IED) with graphite furnace atomic absorption spectrometry was developed for the determination of Co, Ni, Cu, Cd, Sn, Pb, and Bi at sub-ppb levels in water. A 100 mL water sample was adjusted to pH 5.6 with nitric acid and a 1 mol?L–1 ammonium acetate solution, and then passed through an IED (diameter, 47 mm;effective filtering diameter, 35 mm) at a flow rate of 80 - 100 mL?min–1 to preconcentrate seven analytes. The IED was dried at 100?C for 20 min in an electric oven, and 110 - 145 small disks, each 2 mm in diameter, were punched out from the IED. A small disk was introduced into the graphite furnace and atomized according to a heating program. For Cd, Sn, Pb, and Bi measurements, Pd was used as a chemical modifier to enhance the absorbances. Calibration was performed using aqueous standard solutions. The detection limits, corresponding to three times the standard deviation (n = 5) of the blank values, were 0.092 μg·L–1 for Co, 0.12 μg·L–1 for Ni, 0.40 μg·L–1 for Cu, 0.077 μg·L–1 for Cd, 0.92 μg·L–1 for Sn, 0.61 μg·L–1 for Pb, and 0.80 μg·L–1 for Bi with an enrichment factor of 140 using a 100-mL water sample. A spike test for the seven analytes in tap water, rainwater, river water, and mineral drinking water showed quantitative recoveries (93% - 108%).展开更多
For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer ...For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer are used.The principle of measurement is described.The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters.When the fragment flies through the light screen array,the time of passing through each of the screens is recorded by the multi-channel chronograph.According to the time data and the geometrical parameters of the array,the velocity vector and the location of the fragment can be calculated immediately.The presented method can be used to locate the fragment and to measure the real velocity on its flying direction.It can also be used to measure the velocity of a fragment swarm after the system is engineered further.展开更多
A two-year study on temporal variations in the ground water heterotrophic bacterial cell sizes of free living bacteria (FLB) and particle bound bacteria (PBB) from the agricultural, domestic and industrial areas was c...A two-year study on temporal variations in the ground water heterotrophic bacterial cell sizes of free living bacteria (FLB) and particle bound bacteria (PBB) from the agricultural, domestic and industrial areas was carried out from February 2005 to January 2007. The overall mean cell length of FLB and PBB was similar in all the ground water studied. However, the season wise grouped data revealed significant seasonal changes in cell length of FLB and PBB, as smaller bacteria were noticed during rainy season in the ground water in agricultural area in both the years, and only in the second year of study in domestic and industrial areas. Generally, it was noticed that there were summer maximum and rainy minimum values of the cell length of PBB in the ground water in agricultural, domestic and industrial areas in the second year of study. The Pearson's correlations showed the presence of 8 (in agricultural area), 5 (in domestic) and 3 (in industrial) significant correlations with environmental (Physico-chemical) parameters, respectively. The regression analysis revealed that as much as 12% of variation in the mean length of FLB was due to NO3 (+) in agricultural area and 9% due to total solids (+) in domestic area. However, the 8 % variation in bacterial cell size of FLB was due to Mg (+) in industrial area. Whereas, 13 % variation in mean length of PBB was due to SO4 (+) in agricultural area and 10% due to total anions of strong acid (TASA) (+) in domestic area. Furthermore, 10 % of variation was due to PO4 (+) in industrial area. Thus, the statistical analysis revealed that several environmental variables were potentially responsible for some of the temporal variations in aquatic heterotrophic bacterial cell size, suggesting probably the stressed environment in these ecosystems.展开更多
基金supported by the National Key Research and Development Program of China(2022YFB4002100)the Key Program of the National Natural Science Foundation of China(22090032,22090030)。
文摘Direct seawater electrolysis for hydrogen production has been regarded as a viable route to utilize surplus renewable energy and address the climate crisis.However,the harsh electrochemical environment of seawater,particularly the presence of aggressive Cl^(-),has been proven to be prone to parasitic chloride ion oxidation and corrosion reactions,thus restricting seawater electrolyzer lifetime.Herein,hierarchical structure(Ni,Fe)O(OH)@NiCoS nanorod arrays(NAs)catalysts with heterointerfaces and localized oxygen vacancies were synthesized at nickel foam substrates via the combination of hydrothermal and annealing methods to boost seawater dissociation.The hiera rchical nanostructure of NiCoS NAs enhanced electrode charge transfer rate and active surface area to accelerate oxygen evolution reaction(OER)and generated sulfate gradient layers to repulsive aggressive Cl^(-).The fabricated heterostructure and vacancies of(Ni,Fe)O(OH)tuned catalyst electronic structure into an electrophilic state to enhance the binding affinity of hydroxyl intermediates and facilitate the structural transformation into amorphousγ-NiFeOOH for promoting OER.Furthermore,through operando electrochemistry techniques,we found that theγ-NiFeOOH possessing an unsaturated coordination environment and lattice-oxygen-participated OER mechanism can minimize electrode Cl^(-)corrosion enabled by stabilizing the adsorption of OH*intermediates,making it one of the best OER catalysts in the seawater medium reported to date.Consequently,these catalysts can deliver current densities of 100 and 500 mA cm-2for boosting OER at minimal overpotentials of 245and 316 mV,respectively,and thus prevent chloride ion oxidation simultaneously.Impressively,a highly stable anion exchange membrane(AEM)seawater electrolyzer based on the non-noble metal heterostructure electrodes reached a record low degradation rate under 100μV h-1at constant industrial current densities of 400 and 600 mA cm-2over 300 h,which exhibits a promising future for the nonprecious and stable AEMWE in the direct seawater electrolysis industry.
文摘This paper advances the viewpoints and methods of the rapid sample product trial manufacture technique for developing water meter new products by CAD and simulation, computer virtual assembling and optimizing, rapid machining process and measurement etc. as the design and sample product trial manufacture process of water meter new products are long in product development period, and low in product development efficiency in the present time.
文摘A direct analysis method combining an iminodiacetate extraction disk (IED) with graphite furnace atomic absorption spectrometry was developed for the determination of Co, Ni, Cu, Cd, Sn, Pb, and Bi at sub-ppb levels in water. A 100 mL water sample was adjusted to pH 5.6 with nitric acid and a 1 mol?L–1 ammonium acetate solution, and then passed through an IED (diameter, 47 mm;effective filtering diameter, 35 mm) at a flow rate of 80 - 100 mL?min–1 to preconcentrate seven analytes. The IED was dried at 100?C for 20 min in an electric oven, and 110 - 145 small disks, each 2 mm in diameter, were punched out from the IED. A small disk was introduced into the graphite furnace and atomized according to a heating program. For Cd, Sn, Pb, and Bi measurements, Pd was used as a chemical modifier to enhance the absorbances. Calibration was performed using aqueous standard solutions. The detection limits, corresponding to three times the standard deviation (n = 5) of the blank values, were 0.092 μg·L–1 for Co, 0.12 μg·L–1 for Ni, 0.40 μg·L–1 for Cu, 0.077 μg·L–1 for Cd, 0.92 μg·L–1 for Sn, 0.61 μg·L–1 for Pb, and 0.80 μg·L–1 for Bi with an enrichment factor of 140 using a 100-mL water sample. A spike test for the seven analytes in tap water, rainwater, river water, and mineral drinking water showed quantitative recoveries (93% - 108%).
基金Sponsored by Foundation of Department Education of Shaanxi Province of China(03JC31)Key Lab Foundationin Nanjing University of Science and Technology(51453010103SX0201).
文摘For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer are used.The principle of measurement is described.The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters.When the fragment flies through the light screen array,the time of passing through each of the screens is recorded by the multi-channel chronograph.According to the time data and the geometrical parameters of the array,the velocity vector and the location of the fragment can be calculated immediately.The presented method can be used to locate the fragment and to measure the real velocity on its flying direction.It can also be used to measure the velocity of a fragment swarm after the system is engineered further.
文摘A two-year study on temporal variations in the ground water heterotrophic bacterial cell sizes of free living bacteria (FLB) and particle bound bacteria (PBB) from the agricultural, domestic and industrial areas was carried out from February 2005 to January 2007. The overall mean cell length of FLB and PBB was similar in all the ground water studied. However, the season wise grouped data revealed significant seasonal changes in cell length of FLB and PBB, as smaller bacteria were noticed during rainy season in the ground water in agricultural area in both the years, and only in the second year of study in domestic and industrial areas. Generally, it was noticed that there were summer maximum and rainy minimum values of the cell length of PBB in the ground water in agricultural, domestic and industrial areas in the second year of study. The Pearson's correlations showed the presence of 8 (in agricultural area), 5 (in domestic) and 3 (in industrial) significant correlations with environmental (Physico-chemical) parameters, respectively. The regression analysis revealed that as much as 12% of variation in the mean length of FLB was due to NO3 (+) in agricultural area and 9% due to total solids (+) in domestic area. However, the 8 % variation in bacterial cell size of FLB was due to Mg (+) in industrial area. Whereas, 13 % variation in mean length of PBB was due to SO4 (+) in agricultural area and 10% due to total anions of strong acid (TASA) (+) in domestic area. Furthermore, 10 % of variation was due to PO4 (+) in industrial area. Thus, the statistical analysis revealed that several environmental variables were potentially responsible for some of the temporal variations in aquatic heterotrophic bacterial cell size, suggesting probably the stressed environment in these ecosystems.
