Graphene oxide(GO)as a new nano-enhancer in cement-based materials has gained wide attention.However,GO is easy to aggregate in alkaline cement mortar with poor dispersibility.This hinders its application in practical...Graphene oxide(GO)as a new nano-enhancer in cement-based materials has gained wide attention.However,GO is easy to aggregate in alkaline cement mortar with poor dispersibility.This hinders its application in practical infrastructure construction.In this work,GO-M18 polycarboxylate compound superplasticizer(GM)were obtained by compounding the M18 polycarboxylate superplasticizer with GO solution at different mass ratios.The dispersion of GM in alkaline solution was systematically studied.The phases and functional groups of GM were characterized by XRD and FTIR.The effects of GM on the cement mortar hydration and the formation of microstructure were investigated by measuring the heat of hydration,MIP,TG/DSC,and SEM.The results show that the long-chain structure of the M18 polycarboxylate superplasticizer can increase the interlayer spacing of GO and weaken the force between GO sheets.The modified GO can be uniformly dispersed in the cement slurry.GM can accelerate the early hydration process of cement,which can increase the content of Ca(OH)2 and decrease the grain size.It can optimize the pore size distribution of cement-based materials,increase the density of harmless and less harmful pores,thereby improving mechanical properties.Such methods can transform traditional cement-based materials into stronger,more durable composites,which prolong the life of cement-based materials and reduce the amount of cement used for later maintenance.This provides an idea for achieving sustainability goals in civil engineering.展开更多
采用传统固相法制备了新型0.995Bi0.5(Na0.8K0.2)0.5TiO3-0.005(Li y K1-y)SbO3无铅压电陶瓷,利用XRD、SEM等测试技术表征了该陶瓷的晶体结构、表面形貌、压电和介电性能。研究结果表明,在所研究的组成范围内陶瓷材料均能形成纯的钙钛...采用传统固相法制备了新型0.995Bi0.5(Na0.8K0.2)0.5TiO3-0.005(Li y K1-y)SbO3无铅压电陶瓷,利用XRD、SEM等测试技术表征了该陶瓷的晶体结构、表面形貌、压电和介电性能。研究结果表明,在所研究的组成范围内陶瓷材料均能形成纯的钙钛矿固溶体。压电性能随y的增加先增加后减少,在y=10%时压电常数及机电耦合系数达到最大值(d33=111 pC/N,k p=0.220)。展开更多
Effect of Co substitution and annealing treatment on the formation, magnetic properties and microstructure of （NdDyTb）12.3（FeZrNbCu）81.7.xCoxB6 （x=0-15） ribbons prepared by rapid quenching and subsequent anneali...Effect of Co substitution and annealing treatment on the formation, magnetic properties and microstructure of （NdDyTb）12.3（FeZrNbCu）81.7.xCoxB6 （x=0-15） ribbons prepared by rapid quenching and subsequent annealing was systematically investigated by means of differential scanning calorimeter （DSC）, X-ray diffraction （XRD）, high resolution scanning electron microscopy （HRSEM） and vibrating sample magnetometer （VSM）. Phase analysis revealed single-phase material. The remanence polarization Jr and maximum energy product （BH）max increased with increasing x from 0 to 12 and then decreased for x=15. The intrinsic coercivity Hci of （NdOyTb）12.3 （FeZrNbCu）81.7-xCoxB6 ribbons optimally processed decreased from 1308.7 kA/m for x=0 to 817.4 kA/m for x=15. Optimum magnetic properties with Jr=1.041 T, Hci=944.9 EA/m and （BH）max=155.1 kJ/m^3 were achieved by annealing melt-spun ribbon （x=12） at 675 ℃ for 10 min. There was no significant influence of Co substitution on microstructure.展开更多
Low carbon Al2O3 - C refractories specimens were prepared with tabular alumina （3. 0 - 1.0, 1.0 - 0. 5, 0.6-0.2, ≤0.3, ≤0. 045 and ≤0. 02 mm）, active alumina micropowder （≤2 μm ） and silicon （ 〈≤0. 045 mm ...Low carbon Al2O3 - C refractories specimens were prepared with tabular alumina （3. 0 - 1.0, 1.0 - 0. 5, 0.6-0.2, ≤0.3, ≤0. 045 and ≤0. 02 mm）, active alumina micropowder （≤2 μm ） and silicon （ 〈≤0. 045 mm ） as main raw materials. Nano carbon black （N220） and natural graphite flake （ 〈≤0. 074 mm ） were adopted as the carbon sources. The specimens were treated at 800, 1 000, 1 200 and 1 400 ℃ under coke embedded atmosphere. The effects of additions of nano carbon black and graphite flake on mechanical properties and thermal shock resistance of the specimens were stud- ied. Their mechanical properties were measured by three- point bending test and thermal shock resistance was de- termined by water quenching method. The phase compo- sition of the specimens was analyzed with X-ray diffrac- tion and microstruetures were observed through FESEM. The results reveal that： （1） the strengths of A1203 - C refractories with these two carbon sources show no big differences when coked at lower than 1 000 ℃ ; when coked at over 1 200 ℃ , the strengths of the specimens with graphite added are much higher than those of the specimens containing carbon black due to much more sil- icon carbide whiskers formed; （2） since the nano carbon black has small particle size, they can be filled into in- terstice of Al2O3 particles to form the nano carbon net- work structure, absorbing and relieving the thermal stressgenerated from expansion and contraction and reducing the thermal expansion coefficient of the specimens, thus their thermal shock resistance is better than that of the specimens containing graphite ; （ 3 ） low carbon Al2 O3 - C refractories with good mechanical properties and excellent thermal shock resistance can be prepared with combi- nation of nano carbon black and graphite flake.展开更多
A series of Pt-Er/γ-Al2O3 catalysts containing 0. 5 % （mass fraction） platinum and 0.05 %-1.5 % Er were prepared by impregnation of γ-Al2O3 supported with different concentrations of erbium chloride solution. Th...A series of Pt-Er/γ-Al2O3 catalysts containing 0. 5 % （mass fraction） platinum and 0.05 %-1.5 % Er were prepared by impregnation of γ-Al2O3 supported with different concentrations of erbium chloride solution. The surface properties of the catalysts were studied by methods of temperature programmed reduction and temperature programmed desorption. The magnetic behavior of Pt-Er/γ-Al2O3 catalysts were studied with a Faraday magnetic balance and the results show that the addition of Er can affect the surface properties, the catalytic activities, and magnetic behavior of the reforming catalysts. It is found that there is a corresponding relationship between the susceptibility and selectivity of Pt-Er/γ-Al2O3 catalysts. The experimental results show that Er plays the role of electron promoter.展开更多
We consider the D-dimensional SchrSdinger equation under the hyperbolic potential V0（1 -coth（ar））＋ 171 （1 - coth（ar））2. Using a Pekeris-type approximation, the approximate analytical solutions of the problem ...We consider the D-dimensional SchrSdinger equation under the hyperbolic potential V0（1 -coth（ar））＋ 171 （1 - coth（ar））2. Using a Pekeris-type approximation, the approximate analytical solutions of the problem are obtained via the supersymmetric quantum mechanics. The behaviors of energy eigenvalues versus dimension are discussed for various quantum numbers. Useful expectation values as well as the oscillator strength are obtained.展开更多
The effects of the electro-deposition conditions on the crystal structure and the properties of electrolytic manganese dioxide （EMD） were investigated in this paper. The results show that EMD was y-crystal, with san...The effects of the electro-deposition conditions on the crystal structure and the properties of electrolytic manganese dioxide （EMD） were investigated in this paper. The results show that EMD was y-crystal, with sand-like rough interface. The optimal preparation conditions of EMD were 30 min deposition time, and pH=1.0 in MnSO4-H2SO4 solution at 50 ℃. Surfactant （P1） was conducive to the uniform and stable surface ofy-MnO2 film, the impedance and the specific surface area of the electrode modified with y-MnO2 increased by 21.4 times and 75.6 times, respectively. The redox reversibility and the resolution ratio of characteristic peaks with the modified electrode were significantly improved in the benzodiazepines electrochemical reaction. The achievement illustrated that the controllable synthesis ofy-MnO2 film thickness was practical in electrochemical sensors, and the determination reliability of benzodiazepines was improved with y-MnO2 modified electrodes used in environment monitoring technology.展开更多
基金funded by the National Natural Science Foundation of China(No.51872137)and Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Graphene oxide(GO)as a new nano-enhancer in cement-based materials has gained wide attention.However,GO is easy to aggregate in alkaline cement mortar with poor dispersibility.This hinders its application in practical infrastructure construction.In this work,GO-M18 polycarboxylate compound superplasticizer(GM)were obtained by compounding the M18 polycarboxylate superplasticizer with GO solution at different mass ratios.The dispersion of GM in alkaline solution was systematically studied.The phases and functional groups of GM were characterized by XRD and FTIR.The effects of GM on the cement mortar hydration and the formation of microstructure were investigated by measuring the heat of hydration,MIP,TG/DSC,and SEM.The results show that the long-chain structure of the M18 polycarboxylate superplasticizer can increase the interlayer spacing of GO and weaken the force between GO sheets.The modified GO can be uniformly dispersed in the cement slurry.GM can accelerate the early hydration process of cement,which can increase the content of Ca(OH)2 and decrease the grain size.It can optimize the pore size distribution of cement-based materials,increase the density of harmless and less harmful pores,thereby improving mechanical properties.Such methods can transform traditional cement-based materials into stronger,more durable composites,which prolong the life of cement-based materials and reduce the amount of cement used for later maintenance.This provides an idea for achieving sustainability goals in civil engineering.
基金The authors acknowledge the financial support of Natural Science Foundation of China(Contract No.90405015)Program for Changjiang Scholars and Innovative Research Team in University.
文摘采用传统固相法制备了新型0.995Bi0.5(Na0.8K0.2)0.5TiO3-0.005(Li y K1-y)SbO3无铅压电陶瓷,利用XRD、SEM等测试技术表征了该陶瓷的晶体结构、表面形貌、压电和介电性能。研究结果表明,在所研究的组成范围内陶瓷材料均能形成纯的钙钛矿固溶体。压电性能随y的增加先增加后减少,在y=10%时压电常数及机电耦合系数达到最大值(d33=111 pC/N,k p=0.220)。
文摘Effect of Co substitution and annealing treatment on the formation, magnetic properties and microstructure of （NdDyTb）12.3（FeZrNbCu）81.7.xCoxB6 （x=0-15） ribbons prepared by rapid quenching and subsequent annealing was systematically investigated by means of differential scanning calorimeter （DSC）, X-ray diffraction （XRD）, high resolution scanning electron microscopy （HRSEM） and vibrating sample magnetometer （VSM）. Phase analysis revealed single-phase material. The remanence polarization Jr and maximum energy product （BH）max increased with increasing x from 0 to 12 and then decreased for x=15. The intrinsic coercivity Hci of （NdOyTb）12.3 （FeZrNbCu）81.7-xCoxB6 ribbons optimally processed decreased from 1308.7 kA/m for x=0 to 817.4 kA/m for x=15. Optimum magnetic properties with Jr=1.041 T, Hci=944.9 EA/m and （BH）max=155.1 kJ/m^3 were achieved by annealing melt-spun ribbon （x=12） at 675 ℃ for 10 min. There was no significant influence of Co substitution on microstructure.
文摘Low carbon Al2O3 - C refractories specimens were prepared with tabular alumina （3. 0 - 1.0, 1.0 - 0. 5, 0.6-0.2, ≤0.3, ≤0. 045 and ≤0. 02 mm）, active alumina micropowder （≤2 μm ） and silicon （ 〈≤0. 045 mm ） as main raw materials. Nano carbon black （N220） and natural graphite flake （ 〈≤0. 074 mm ） were adopted as the carbon sources. The specimens were treated at 800, 1 000, 1 200 and 1 400 ℃ under coke embedded atmosphere. The effects of additions of nano carbon black and graphite flake on mechanical properties and thermal shock resistance of the specimens were stud- ied. Their mechanical properties were measured by three- point bending test and thermal shock resistance was de- termined by water quenching method. The phase compo- sition of the specimens was analyzed with X-ray diffrac- tion and microstruetures were observed through FESEM. The results reveal that： （1） the strengths of A1203 - C refractories with these two carbon sources show no big differences when coked at lower than 1 000 ℃ ; when coked at over 1 200 ℃ , the strengths of the specimens with graphite added are much higher than those of the specimens containing carbon black due to much more sil- icon carbide whiskers formed; （2） since the nano carbon black has small particle size, they can be filled into in- terstice of Al2O3 particles to form the nano carbon net- work structure, absorbing and relieving the thermal stressgenerated from expansion and contraction and reducing the thermal expansion coefficient of the specimens, thus their thermal shock resistance is better than that of the specimens containing graphite ; （ 3 ） low carbon Al2 O3 - C refractories with good mechanical properties and excellent thermal shock resistance can be prepared with combi- nation of nano carbon black and graphite flake.
文摘A series of Pt-Er/γ-Al2O3 catalysts containing 0. 5 % （mass fraction） platinum and 0.05 %-1.5 % Er were prepared by impregnation of γ-Al2O3 supported with different concentrations of erbium chloride solution. The surface properties of the catalysts were studied by methods of temperature programmed reduction and temperature programmed desorption. The magnetic behavior of Pt-Er/γ-Al2O3 catalysts were studied with a Faraday magnetic balance and the results show that the addition of Er can affect the surface properties, the catalytic activities, and magnetic behavior of the reforming catalysts. It is found that there is a corresponding relationship between the susceptibility and selectivity of Pt-Er/γ-Al2O3 catalysts. The experimental results show that Er plays the role of electron promoter.
文摘We consider the D-dimensional SchrSdinger equation under the hyperbolic potential V0（1 -coth（ar））＋ 171 （1 - coth（ar））2. Using a Pekeris-type approximation, the approximate analytical solutions of the problem are obtained via the supersymmetric quantum mechanics. The behaviors of energy eigenvalues versus dimension are discussed for various quantum numbers. Useful expectation values as well as the oscillator strength are obtained.
基金Funded by the Fundamental and Advanced Research Projects of Chongqing Science and Technology Commission(No.2013jj B20001)
文摘The effects of the electro-deposition conditions on the crystal structure and the properties of electrolytic manganese dioxide （EMD） were investigated in this paper. The results show that EMD was y-crystal, with sand-like rough interface. The optimal preparation conditions of EMD were 30 min deposition time, and pH=1.0 in MnSO4-H2SO4 solution at 50 ℃. Surfactant （P1） was conducive to the uniform and stable surface ofy-MnO2 film, the impedance and the specific surface area of the electrode modified with y-MnO2 increased by 21.4 times and 75.6 times, respectively. The redox reversibility and the resolution ratio of characteristic peaks with the modified electrode were significantly improved in the benzodiazepines electrochemical reaction. The achievement illustrated that the controllable synthesis ofy-MnO2 film thickness was practical in electrochemical sensors, and the determination reliability of benzodiazepines was improved with y-MnO2 modified electrodes used in environment monitoring technology.
