A rapid and more efficient method was developed to prepare nucleus/shell titania/hydroxyapatite (TiO2/HAP) complex nanophotocatalyst. Hydroxyapatite (5 μm) which had been dissolved with 0.1 mol/L HCI was formed o...A rapid and more efficient method was developed to prepare nucleus/shell titania/hydroxyapatite (TiO2/HAP) complex nanophotocatalyst. Hydroxyapatite (5 μm) which had been dissolved with 0.1 mol/L HCI was formed on the surface of the nanosized anatase titania powders by increasing the pH value of the solution at 90℃ in the water bath for only several hours .The microstructure and morphology of the resulting sample were investigated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and atomic force microscope (AFM). The results indicated that nucleus/shell structural TiO2/HAP was formed in our experiments, and the thickness of the coating layer was about 5 nm. Photocatalytic decomposition of methyl orange was utilized to test the photocatalysis of the resulting samples and the result was compared with that of pure anatase titania powders (about 20 nm). It was shown that the photocatalytic activity of the sample was not decreased due to the coating of HAP.展开更多
Copper oxide has aroused great concern in energy storage fields due to its properties of high theoretical capacitance,low cost and mild toxicity.However,its wide application still remains challenges owing to its poor ...Copper oxide has aroused great concern in energy storage fields due to its properties of high theoretical capacitance,low cost and mild toxicity.However,its wide application still remains challenges owing to its poor electrical conductivity and unstable cycling life.Binder-free foam electrodes possess abundant porous structures and high specific surface area,which could get good contact with electrolyte.Herein,we demonstrate Ag nanoparticles decorated CuxO nanowires grown spontaneously on copper foam(CF)electrode for asymmetric supercapacitor.The skeleton structure of CF provides large amounts of active sites for the growth of CuxO nanowires.Moreover,Ag nanoparticles further decrease the internal resistance and enhance the electrochemical performance.Ag/CuxO/CF-40 electrode presents a high area specific capacitance of 1192 mF cm^(-2)at 2 mA cm^(-2)and the influence of surface capacitance-dominated process and diffusion-controlled process are discussed in detail.Besides,the energy density of the as-prepared asymmetric supercapacitor(ASC)reaches 46.32 mWh cm^(-2)at a power density of 3.00 mW cm^(-2).A 2V LED is lighted successfully by two ASC in series.This work provides a new strategy to prepare low internal resistance and binder-free flexible Ag/CuxO/CF electrode,which demonstrates a good potential application in flexible supercapacitors or other wearable electronic devices.展开更多
This paper extends the unknown control coefficients with lower and upper constant bounds to the ones which may take arbitrarily large and /or small values.Since the existing methods are no longer applicable and the te...This paper extends the unknown control coefficients with lower and upper constant bounds to the ones which may take arbitrarily large and /or small values.Since the existing methods are no longer applicable and the technical obstacles caused by the extensions are essential,new control design scheme should be exploited to the global practical tracking.By the approaches of Nussbaum-gain and adding a power integrator,the authors successfully propose the design scheme of the adaptive practical tracking controller for the systems.It is shown that the designed controller guarantees that all the closed-loop system states are bounded and the tracking error becomes prescribed arbitrarily small after a finite time.展开更多
In this paper, the global asymptotic stabilization by output feedback is investigated for a class of uncertain nonlinear systems with unmeasured states dependent growth. Compared with the closely related works, the re...In this paper, the global asymptotic stabilization by output feedback is investigated for a class of uncertain nonlinear systems with unmeasured states dependent growth. Compared with the closely related works, the remarkableness of the paper is that either the growth rate is an unknown constant or the dimension of the closed-loop system is significantly reduced, mainly due to the introduction of a distinct dynamic high-gain observer based on a new updating law. Motivated by the related stabilization results, and by skillfully using the methods of universal control and backstepping, we obtain the design scheme to an adaptive output-feedback stabilizing controller to guarantee the global asymptotic stability of the resulting closed-loop system. Additionally, a numerical example is considered to demonstrate the effectiveness of the proposed method.展开更多
Production cost,capacitance,and electrode materials safety are the key factors to be concerned about for supercapacitors.In this work,a type of carbon nanosheets was produced through the carbonization of tripotassium ...Production cost,capacitance,and electrode materials safety are the key factors to be concerned about for supercapacitors.In this work,a type of carbon nanosheets was produced through the carbonization of tripotassium citrate monohydrate and nitric acidification.Subsequently,a well-designed manganese dioxide/carbon nanosheets composite was synthesized through hydrothermal treating.The carbon nanosheets served as the substrate for growing the manganese dioxide,regulating its distribution,and preventing it from inhomogeneous dimensions and severe agglomeration.Many manganese dioxide nanosheets grew vertically on the numerous functional groups generated on the surface of the carbon nanosheets during acidification.The synergistic combination of carbon nanosheets and manganese dioxide tailors the electrochemical performance of the composite,which benefits from the excellent conductivity and stability of carbon nanosheets.The carbon nanosheets derived from tripotassium citrate monohydrate are conducive to the remarkable performance of manganese dioxide/carbon nanosheets electrode.Finally,an asymmetric supercapacitor with active carbon as the cathode and manganese dioxide/carbon nanosheets as the anode was assembled,achieving an outstanding energy density of 54.68 Wh·kg^(−1) and remarkable power density of 6399.2 W·kg^(−1) superior to conventional lead-acid batteries.After 10000 charge-discharge cycles,the device retained 75.3%of the initial capacitance,showing good cycle stability.Two assembled asymmetric supercapacitors in series charged for 3 min could power a yellow light emitting diode with an operating voltage of 2 V for 2 min.This study may provide valuable insights for applying carbon materials and manganese dioxide in the energy storage field.展开更多
文摘A rapid and more efficient method was developed to prepare nucleus/shell titania/hydroxyapatite (TiO2/HAP) complex nanophotocatalyst. Hydroxyapatite (5 μm) which had been dissolved with 0.1 mol/L HCI was formed on the surface of the nanosized anatase titania powders by increasing the pH value of the solution at 90℃ in the water bath for only several hours .The microstructure and morphology of the resulting sample were investigated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and atomic force microscope (AFM). The results indicated that nucleus/shell structural TiO2/HAP was formed in our experiments, and the thickness of the coating layer was about 5 nm. Photocatalytic decomposition of methyl orange was utilized to test the photocatalysis of the resulting samples and the result was compared with that of pure anatase titania powders (about 20 nm). It was shown that the photocatalytic activity of the sample was not decreased due to the coating of HAP.
基金supported by Key R&D Program of Zhenjiang(GY2018016).
文摘Copper oxide has aroused great concern in energy storage fields due to its properties of high theoretical capacitance,low cost and mild toxicity.However,its wide application still remains challenges owing to its poor electrical conductivity and unstable cycling life.Binder-free foam electrodes possess abundant porous structures and high specific surface area,which could get good contact with electrolyte.Herein,we demonstrate Ag nanoparticles decorated CuxO nanowires grown spontaneously on copper foam(CF)electrode for asymmetric supercapacitor.The skeleton structure of CF provides large amounts of active sites for the growth of CuxO nanowires.Moreover,Ag nanoparticles further decrease the internal resistance and enhance the electrochemical performance.Ag/CuxO/CF-40 electrode presents a high area specific capacitance of 1192 mF cm^(-2)at 2 mA cm^(-2)and the influence of surface capacitance-dominated process and diffusion-controlled process are discussed in detail.Besides,the energy density of the as-prepared asymmetric supercapacitor(ASC)reaches 46.32 mWh cm^(-2)at a power density of 3.00 mW cm^(-2).A 2V LED is lighted successfully by two ASC in series.This work provides a new strategy to prepare low internal resistance and binder-free flexible Ag/CuxO/CF electrode,which demonstrates a good potential application in flexible supercapacitors or other wearable electronic devices.
基金supported by the National Natural Science Foundations of China under Grant No.60974003 and 61143011the Natural Science Foundation for Distinguished Young Scholar of Shandong Province of China under Grant No.JQ200919+5 种基金the Program for New Century Excellent Talents in University of China under Grant No.NCET-07-0513the Key Science and Technique Foundation of Ministry of Education of China under Grant No.108079the Excellent Young and Middle-Aged Scientist Award Grant of Shandong Province of China under Grant No.2007BS01010the Independent Innovation Foundation of Shandong University under Grant No.2009JQ008the Scholarship Award for Excellent Doctoral Student granted by Ministry of Educationthe Graduate Independent Innovation Foundation of Shandong University
文摘This paper extends the unknown control coefficients with lower and upper constant bounds to the ones which may take arbitrarily large and /or small values.Since the existing methods are no longer applicable and the technical obstacles caused by the extensions are essential,new control design scheme should be exploited to the global practical tracking.By the approaches of Nussbaum-gain and adding a power integrator,the authors successfully propose the design scheme of the adaptive practical tracking controller for the systems.It is shown that the designed controller guarantees that all the closed-loop system states are bounded and the tracking error becomes prescribed arbitrarily small after a finite time.
基金supported by the National Natural Science Foundations of China (Nos. 60974003, 61143011, 61273084, 61233014)the Natural Science Foundation for Distinguished Young Scholar of Shandong Province of China (No. JQ200919)the Independent Innovation Foundation of Shandong University (No. 2012JC014)
文摘In this paper, the global asymptotic stabilization by output feedback is investigated for a class of uncertain nonlinear systems with unmeasured states dependent growth. Compared with the closely related works, the remarkableness of the paper is that either the growth rate is an unknown constant or the dimension of the closed-loop system is significantly reduced, mainly due to the introduction of a distinct dynamic high-gain observer based on a new updating law. Motivated by the related stabilization results, and by skillfully using the methods of universal control and backstepping, we obtain the design scheme to an adaptive output-feedback stabilizing controller to guarantee the global asymptotic stability of the resulting closed-loop system. Additionally, a numerical example is considered to demonstrate the effectiveness of the proposed method.
基金This work is financially supported by Six Talents Peak Project in Jiangsu Province(Grant No.2011-ZBZZ045)Key R&D Program of Zhenjiang(Grant No.GY2018016)Innovative Training Program in Jiangsu University(Grant No.Y18A017).
文摘Production cost,capacitance,and electrode materials safety are the key factors to be concerned about for supercapacitors.In this work,a type of carbon nanosheets was produced through the carbonization of tripotassium citrate monohydrate and nitric acidification.Subsequently,a well-designed manganese dioxide/carbon nanosheets composite was synthesized through hydrothermal treating.The carbon nanosheets served as the substrate for growing the manganese dioxide,regulating its distribution,and preventing it from inhomogeneous dimensions and severe agglomeration.Many manganese dioxide nanosheets grew vertically on the numerous functional groups generated on the surface of the carbon nanosheets during acidification.The synergistic combination of carbon nanosheets and manganese dioxide tailors the electrochemical performance of the composite,which benefits from the excellent conductivity and stability of carbon nanosheets.The carbon nanosheets derived from tripotassium citrate monohydrate are conducive to the remarkable performance of manganese dioxide/carbon nanosheets electrode.Finally,an asymmetric supercapacitor with active carbon as the cathode and manganese dioxide/carbon nanosheets as the anode was assembled,achieving an outstanding energy density of 54.68 Wh·kg^(−1) and remarkable power density of 6399.2 W·kg^(−1) superior to conventional lead-acid batteries.After 10000 charge-discharge cycles,the device retained 75.3%of the initial capacitance,showing good cycle stability.Two assembled asymmetric supercapacitors in series charged for 3 min could power a yellow light emitting diode with an operating voltage of 2 V for 2 min.This study may provide valuable insights for applying carbon materials and manganese dioxide in the energy storage field.