An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode(nano-PPCPE)has been successfully developed,and used to detect Cd^2+ and Pb^2+.The experimental results showed that the electrochem...An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode(nano-PPCPE)has been successfully developed,and used to detect Cd^2+ and Pb^2+.The experimental results showed that the electrochemical performance of nanoPPCPE is evidently better than both glassy carbon electrode(GCE)and pure carbon paste electrode(CPE).Then the prepared nano-PPCPE was applied to detect Cd^2+ and Pb^2+in standard solution,the results showed that the electrodes can quantitatively detect trace Cd^2+ and Pb^2+,which has great significance in electrochemical analysis and detection.The linear ranges between the target ions concentration and the D PASV current were from 0.1-3.0 μmol/L,0.05-4.0 μmol/L for Cd^2+ and Pb^2+,respectively.And the detection limits were 0.0780 μmol/L and 0.0292 μmol/L,respectively.Moreover,the preparation of the nano-PPCPE is cheap,simple and has important practical value.展开更多
A 3-dimensional unit cell model is developed for analyzing effective thermal conductivity of xonotlite-aerogelcomposite insulation material based on its microstructure features. Effective thermal conductivity comparis...A 3-dimensional unit cell model is developed for analyzing effective thermal conductivity of xonotlite-aerogelcomposite insulation material based on its microstructure features. Effective thermal conductivity comparisonsbetween xonotlite-type calcium silicate and aerogel as well as xonotlite-aerogel composite insulation material arepresented. It is shown that the density of xonotlite-type calcium silicate is the key factor affecting the effectivethermal conductivity of xonotlite-aerogel composite insulation material, and the density of aerogel has little influence.The effective thermal conductivity can be lowered greatly by composite of the two materials at an elevatedtemperature.展开更多
Transition metals like Au,Ag,and Cu have been reported to be quite active for CO_(2) reduction.In this study,we use density functional theory(DFT)calculation to investigate the electronic structure and catalytic perfo...Transition metals like Au,Ag,and Cu have been reported to be quite active for CO_(2) reduction.In this study,we use density functional theory(DFT)calculation to investigate the electronic structure and catalytic performance of Au,Ag,Cu and their alloys for CO_(2) reduction reaction(CO_(2)RR).Theoretical calculations identified the combination of Ag,Cu,and Au in a face-centered cubic(fcc)alloy as an outstanding electrocatalyst for CO_(2) reduction to CO,with Cu as the active site.The d-orbital projected density of state(PDOS)profile suggests that alloying alters the electronic structure of the Cu site,thereby affecting the Gibbs free energy change for the formation of*COOH intermediate(ΔG_(*COOH)).To demonstrate the theoretical prediction experimentally,we employ a top-down dealloying approach to synthesize a nanoporous structured AgCuAu alloy(NP-Ag_(5)Cu_(5)Au_(5)).Electrochemical experiments validate that the ternary alloy catalyst is clearly better than unary and binary catalysts,showing a Faradaic efficiency(FE)for CO over 90%across a broad potential range of 0.6 V,with a peak of approximately 96%at-0.573 V vs.RHE.This study underscores the potential of multi-component alloys in CO_(2)RR and establishes a theoretical basis for designing efficient catalysts for CO_(2) utilization.展开更多
Clustering of Ti on carbon nanostructures has proved to be an obstacle in their use as hydrogen storage materials. Using density functional theory we show that Ti atoms will not cluster at moderate concentrations when...Clustering of Ti on carbon nanostructures has proved to be an obstacle in their use as hydrogen storage materials. Using density functional theory we show that Ti atoms will not cluster at moderate concentrations when doped into nanoporous graphene. Since each Ti atom can bind up to three hydrogen molecules with an average binding energy of 0.54 eV/H2, this material can be ideal for storing hydrogen under ambient thermodynamic conditions. In addition, nanoporous graphene is magnetic with or without Ti doping, but when it is fully saturated with hydrogen, the magnetism disappears. This novel feature suggests that nanoporous graphene cannot only be used for storing hydrogen, but also as a hydrogen sensor.展开更多
Low-k interconnection is one of the key concepts in the development of high-speed ultra-large-scale integrated（ULSI） circuits.To determine the Young＇s modulus of ultra thin,low hardness and fragile low-k porous fil...Low-k interconnection is one of the key concepts in the development of high-speed ultra-large-scale integrated（ULSI） circuits.To determine the Young＇s modulus of ultra thin,low hardness and fragile low-k porous films more accurately,a wideband differential confocal configured laser detected and laser-generated surface acoustic wave（DCC/LD LSAW） detection system is developed.Based on the light deflection sensitivity detection principle, with a novel differential confocal configuration,this DCC/LD LSAW system extends the traditional laser generated surface acoustic wave（LSAW） detection system＇s working frequency band,making the detected SAW signals less affected by the hard substrate and providing more information about the thin porous low-k film under test.Thus it has the ability to obtain more accurate measurement results.Its detecting principle is explained and a sample of porous silica film on Si（100） is tested.A procedure of fitting an experimental SAW dispersion curve with theoretical dispersion curves was carried out in the high frequency band newly achieved by the DCC/LD LSAW system.A comparison of the measurement results of the DCC/LD LSAW with those from the traditional LSAW shows that this newly developed DCC/LD LSAW can dramatically improve the Young＇s modulus measuring accuracy of such porous low-k films.展开更多
Background Drug-eluting stents represent a major advance in interventional cardiology. However, the current drug- eluting stents have significant limitations. One of the major problems is very late stent thrombosis, w...Background Drug-eluting stents represent a major advance in interventional cardiology. However, the current drug- eluting stents have significant limitations. One of the major problems is very late stent thrombosis, which is likely caused by inflammation and a hypersensitivity reaction related to a polymer on the stent. A polymer-free sirolimus-eluting stent with a unique nano-porous surface has been developed. This study aimed to evaluate this novel polymer-free sirolimus- eluting stent for its efficacy and safety in a pig model. Methods Stents were directly coated with sirolimus （a drug concentration of 2.2 μg/mm2 on the stent surface）. The polymer-free sirolimus-eluting stents （PFSES） were compared to standard polymer-coated sirolimus-eluting stents （PCSES） and bare-metal stents （BMS） in 18 pigs. Results At one month the degree of neointimal hyperplasia was similar between the two sirolimus-eluting stent groups and was significantly less compared to BMS （（1.93±0.51） mm2, （1.57±0.69） mm2 vs. （4.45±1.05） mm2, P 〈0.05）At three months, PFSES maintained the low level of neointima （（2.41±0.99） mm2 vs. （4.32±1.16） mm2, P 〈0.05）, whereas PCSES had developed significant neointimal proliferation similar to BMS. The inflammation level was significantly higher in PCSES when compared with BMS three months post-implantation （2.50±0.55 vs. 0.83±0.75, P 〈0.05） whereas PFSES showed a low level of inflammation comparable to PCSES （1.33±0.52 vs. 2.50±0.55, P 〈0.05）. Conclusion The PFSES is effective and safe. and appears to be suoerior to standard PCSEs.展开更多
Agglomerated Pd catalysts with the nano-porous structure were simply prepared by one-step reduction reaction without using any stabilizer. The Pd catalysts show a high catalytic activity for the decomposition of formi...Agglomerated Pd catalysts with the nano-porous structure were simply prepared by one-step reduction reaction without using any stabilizer. The Pd catalysts show a high catalytic activity for the decomposition of formic acid at room temperature. Among all the Pd catalysts tested, the Pdug catalyst exhibits the highest catalytic activity. Moreover, the breakthrough of the advanced catalysts is that the above agglomerated Pd catalysts can be easily separated from the liquid system to control the catalytic reaction at any time, which may further promote the practical application of formic acid as a H2 storage material.展开更多
High elastic energy density and high-efficiency ionic electromechanical actuators were prepared from aligned activated microwave exfoliated graphite oxide(A-aMEGO)/polymer nano-composites,and the electromechanical per...High elastic energy density and high-efficiency ionic electromechanical actuators were prepared from aligned activated microwave exfoliated graphite oxide(A-aMEGO)/polymer nano-composites,and the electromechanical performance was characterized.The elastic modulus and elastic energy density of the ionic actuators can be tuned over a wide range by varying the polymer(poly(vinylidene fluoride/chlorotrifluoroethylene)[P(VDF-CTFE)])concentration in the nano-composite actuators.The A-aMEGO/P(VDF-CTFE)nano-composite actuators with 35 wt.%of polymer content exhibit an elastic energy density higher than 5 J/cm^(3) and an electromechanical conversion efficiency higher than 3.5%,induced under 4 V.The results show the promise of high-density highly aligned graphene electrodes for high-performance ionic electromechanical transduction devices.展开更多
基金the National Key Research and Development Program of China (No.2018YFC1602905)the National Natural Science Foundation of China (Nos.61871180 and 61527806)+1 种基金the Natural Science Foundation of Hunan Province (No.2017JJ2069)Hunan Key Research Project (No.2017SK2174) for the financial supports
文摘An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode(nano-PPCPE)has been successfully developed,and used to detect Cd^2+ and Pb^2+.The experimental results showed that the electrochemical performance of nanoPPCPE is evidently better than both glassy carbon electrode(GCE)and pure carbon paste electrode(CPE).Then the prepared nano-PPCPE was applied to detect Cd^2+ and Pb^2+in standard solution,the results showed that the electrodes can quantitatively detect trace Cd^2+ and Pb^2+,which has great significance in electrochemical analysis and detection.The linear ranges between the target ions concentration and the D PASV current were from 0.1-3.0 μmol/L,0.05-4.0 μmol/L for Cd^2+ and Pb^2+,respectively.And the detection limits were 0.0780 μmol/L and 0.0292 μmol/L,respectively.Moreover,the preparation of the nano-PPCPE is cheap,simple and has important practical value.
基金supported by the National Natural Science Foundation of China (No.50806021)Program for Changjiang Scholars and Inn ovative Researeh Team in University (PCSIRT0720).
文摘A 3-dimensional unit cell model is developed for analyzing effective thermal conductivity of xonotlite-aerogelcomposite insulation material based on its microstructure features. Effective thermal conductivity comparisonsbetween xonotlite-type calcium silicate and aerogel as well as xonotlite-aerogel composite insulation material arepresented. It is shown that the density of xonotlite-type calcium silicate is the key factor affecting the effectivethermal conductivity of xonotlite-aerogel composite insulation material, and the density of aerogel has little influence.The effective thermal conductivity can be lowered greatly by composite of the two materials at an elevatedtemperature.
基金supported by Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive Application(No.ZDSYS20220527171407017)。
文摘Transition metals like Au,Ag,and Cu have been reported to be quite active for CO_(2) reduction.In this study,we use density functional theory(DFT)calculation to investigate the electronic structure and catalytic performance of Au,Ag,Cu and their alloys for CO_(2) reduction reaction(CO_(2)RR).Theoretical calculations identified the combination of Ag,Cu,and Au in a face-centered cubic(fcc)alloy as an outstanding electrocatalyst for CO_(2) reduction to CO,with Cu as the active site.The d-orbital projected density of state(PDOS)profile suggests that alloying alters the electronic structure of the Cu site,thereby affecting the Gibbs free energy change for the formation of*COOH intermediate(ΔG_(*COOH)).To demonstrate the theoretical prediction experimentally,we employ a top-down dealloying approach to synthesize a nanoporous structured AgCuAu alloy(NP-Ag_(5)Cu_(5)Au_(5)).Electrochemical experiments validate that the ternary alloy catalyst is clearly better than unary and binary catalysts,showing a Faradaic efficiency(FE)for CO over 90%across a broad potential range of 0.6 V,with a peak of approximately 96%at-0.573 V vs.RHE.This study underscores the potential of multi-component alloys in CO_(2)RR and establishes a theoretical basis for designing efficient catalysts for CO_(2) utilization.
文摘Clustering of Ti on carbon nanostructures has proved to be an obstacle in their use as hydrogen storage materials. Using density functional theory we show that Ti atoms will not cluster at moderate concentrations when doped into nanoporous graphene. Since each Ti atom can bind up to three hydrogen molecules with an average binding energy of 0.54 eV/H2, this material can be ideal for storing hydrogen under ambient thermodynamic conditions. In addition, nanoporous graphene is magnetic with or without Ti doping, but when it is fully saturated with hydrogen, the magnetism disappears. This novel feature suggests that nanoporous graphene cannot only be used for storing hydrogen, but also as a hydrogen sensor.
基金Project supported by the National Science Foundation of China(Nos.60723004,61072013)
文摘Low-k interconnection is one of the key concepts in the development of high-speed ultra-large-scale integrated（ULSI） circuits.To determine the Young＇s modulus of ultra thin,low hardness and fragile low-k porous films more accurately,a wideband differential confocal configured laser detected and laser-generated surface acoustic wave（DCC/LD LSAW） detection system is developed.Based on the light deflection sensitivity detection principle, with a novel differential confocal configuration,this DCC/LD LSAW system extends the traditional laser generated surface acoustic wave（LSAW） detection system＇s working frequency band,making the detected SAW signals less affected by the hard substrate and providing more information about the thin porous low-k film under test.Thus it has the ability to obtain more accurate measurement results.Its detecting principle is explained and a sample of porous silica film on Si（100） is tested.A procedure of fitting an experimental SAW dispersion curve with theoretical dispersion curves was carried out in the high frequency band newly achieved by the DCC/LD LSAW system.A comparison of the measurement results of the DCC/LD LSAW with those from the traditional LSAW shows that this newly developed DCC/LD LSAW can dramatically improve the Young＇s modulus measuring accuracy of such porous low-k films.
文摘Background Drug-eluting stents represent a major advance in interventional cardiology. However, the current drug- eluting stents have significant limitations. One of the major problems is very late stent thrombosis, which is likely caused by inflammation and a hypersensitivity reaction related to a polymer on the stent. A polymer-free sirolimus-eluting stent with a unique nano-porous surface has been developed. This study aimed to evaluate this novel polymer-free sirolimus- eluting stent for its efficacy and safety in a pig model. Methods Stents were directly coated with sirolimus （a drug concentration of 2.2 μg/mm2 on the stent surface）. The polymer-free sirolimus-eluting stents （PFSES） were compared to standard polymer-coated sirolimus-eluting stents （PCSES） and bare-metal stents （BMS） in 18 pigs. Results At one month the degree of neointimal hyperplasia was similar between the two sirolimus-eluting stent groups and was significantly less compared to BMS （（1.93±0.51） mm2, （1.57±0.69） mm2 vs. （4.45±1.05） mm2, P 〈0.05）At three months, PFSES maintained the low level of neointima （（2.41±0.99） mm2 vs. （4.32±1.16） mm2, P 〈0.05）, whereas PCSES had developed significant neointimal proliferation similar to BMS. The inflammation level was significantly higher in PCSES when compared with BMS three months post-implantation （2.50±0.55 vs. 0.83±0.75, P 〈0.05） whereas PFSES showed a low level of inflammation comparable to PCSES （1.33±0.52 vs. 2.50±0.55, P 〈0.05）. Conclusion The PFSES is effective and safe. and appears to be suoerior to standard PCSEs.
文摘Agglomerated Pd catalysts with the nano-porous structure were simply prepared by one-step reduction reaction without using any stabilizer. The Pd catalysts show a high catalytic activity for the decomposition of formic acid at room temperature. Among all the Pd catalysts tested, the Pdug catalyst exhibits the highest catalytic activity. Moreover, the breakthrough of the advanced catalysts is that the above agglomerated Pd catalysts can be easily separated from the liquid system to control the catalytic reaction at any time, which may further promote the practical application of formic acid as a H2 storage material.
基金financially supported by the Key Basic and Applied Research Program of Guangdong Province,China(2019B030302010)the National Key Research and Development Program of China(2018YFA0703605)+1 种基金the National Science Foundation of China(52122105,51971150)the Science and Technology Innovation Commission Shenzhen(RCJC20221008092730037,20220804091920001)。
基金supported by NSF under grant number CMMI-1130437 and by a grant from Korean Institute of Science and Technology。
文摘High elastic energy density and high-efficiency ionic electromechanical actuators were prepared from aligned activated microwave exfoliated graphite oxide(A-aMEGO)/polymer nano-composites,and the electromechanical performance was characterized.The elastic modulus and elastic energy density of the ionic actuators can be tuned over a wide range by varying the polymer(poly(vinylidene fluoride/chlorotrifluoroethylene)[P(VDF-CTFE)])concentration in the nano-composite actuators.The A-aMEGO/P(VDF-CTFE)nano-composite actuators with 35 wt.%of polymer content exhibit an elastic energy density higher than 5 J/cm^(3) and an electromechanical conversion efficiency higher than 3.5%,induced under 4 V.The results show the promise of high-density highly aligned graphene electrodes for high-performance ionic electromechanical transduction devices.
