A series of nitrogen-doped SrMoO_(4) with different Sr/N mole ratio (R=0,0.05,0.10,0.15,0.20,0.40,and 0.60) were synthesized using urea as the N source via the vapor-thermal method.The photocatalytic degradation abili...A series of nitrogen-doped SrMoO_(4) with different Sr/N mole ratio (R=0,0.05,0.10,0.15,0.20,0.40,and 0.60) were synthesized using urea as the N source via the vapor-thermal method.The photocatalytic degradation ability of all samples was evaluated using methylene blue (MB) as a target contaminant.The band gaps of N-doped samples are all higher than that of pristine ones,which is only 3.12 eV.BET specific surface area S_(BET) and pore volume are increased due to the N doping.And the greater increase of S_(BET),the faster the photodegradation speed of methylene blue on SrMoO_(4).More specifically,the degradation efficiency of MB is improved up to 87%in 100 min.展开更多
The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi 3.8(CoMn) 1.2 on its electrochemical performances and performances at high temperatures were investigated.It is fou...The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi 3.8(CoMn) 1.2 on its electrochemical performances and performances at high temperatures were investigated.It is found that the addition of aluminum brings about a significant increase in the discharge capacity at high temperatures,and the capacity decay during repeated charge-discharge cycles and the self-discharge are both suppressed, while the rate capability decreases.The alloy containing zirconium exhibits a longer cycle life and a better rate capability,but a much lower discharge capacity.The addition of titanium improves the rate capability, but the capacity decreases greatly.An X-ray diffraction analysis indicates that a second phase exists in the alloy with additive Zr or Ti,which improves the discharge-rate characteristics,and the superior stability of the alloy with additive Al may be due to the expansion of lattice parameters and cell volume.展开更多
Infrared emissivity was studied in Zn0.99M0.01O(M is Mn,Fe or Ni) and Zn1-xCoxO(x=0.01,0.02,0.03 and 0.04) powders synthesized by solid-state reaction at various temperatures.XRD patterns confirm the wurtzite structur...Infrared emissivity was studied in Zn0.99M0.01O(M is Mn,Fe or Ni) and Zn1-xCoxO(x=0.01,0.02,0.03 and 0.04) powders synthesized by solid-state reaction at various temperatures.XRD patterns confirm the wurtzite structure of the prepared samples.No peaks of other phases arising from impurities are detected in Mn-and Co-doped ZnO,but the peaks of ZnFe2O4 and NiO are observed in Zn0.99Fe0.01O and Zn 0.99 Ni 0.01 O.The SEM observations indicate that with larger grain sizes than those of Zn0.99Fe0.01O and Zn0.99Ni0.01O,Co-doped ZnO exhibits smooth grain surfaces.The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.01O are much stronger than those in Co-doped ZnO.Co ions are dissolved into the ZnO lattice with Co2+ state from XPS spectra analysis.The infrared emissivity results imply that the emissivity of Zn0.99Ni0.01 O is the highest(0.829) and that of Zn 0.99 Co 0.01 O is the lowest(0.784) at 1 200 C.The emissivity of Zn0.99Co0.01O decreases to the minimum(0.752) at 1 150 C and then increases with growing calcination temperature.As the Co doping content grows,the emissivity of Co-doped ZnO calcined at 1 200 C falls to 0.758 in the molar fraction of 3% and then ascends.展开更多
The microstructures of doped tungsten deformed by multi-pass hot continuous rolling were investigated, and the stress and strain fields were simulated by finite element(FE) method. After the continuous rolling, the gr...The microstructures of doped tungsten deformed by multi-pass hot continuous rolling were investigated, and the stress and strain fields were simulated by finite element(FE) method. After the continuous rolling, the grains of the tungsten rod were refined, and the microhardness was improved; however, a ring region of abnormal grain growth was present at a distance of about 3/5 R(R is the radius of the rod) from the center of the cross section. FE modeling results showed that the equivalent residual strains were minimum around the region of abnormal grain growth; this was due to the release of strain energy by severe plastic deformation, leading a situation where the migration force of grain boundaries was higher than the pinning force of potassium bubbles. By decreasing the initial rolling temperature and rolling speeds, the inhomogeneity of the equivalent residual stain decreased, improving the microstructure uniformity of the doped tungsten.展开更多
Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped Co...Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped CoP)nanoparticles has been investigated through a facile gaseous phosphorization using cobalt vanadium oxide or hydroxide(Co-V hydr(oxy)oxide)as precursor.The physical characterization shows that the homogeneous dispersion of V element on V-doped CoP nanoparticles have obtained,which may imply the enhanced electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The electrochemical measurements of the prepared V-doped CoP in alkaline electrolyte demonstrate the superior electrocatalytic activity for both HER(overpotential of 235 mV@10 mA cm^-2)and OER(overpotential of 340 mV@10 mA cm^-2).Further,V-doped CoP nanoparticles used as anode and cathode simultaneously in a cell require only 370 mV to achieve a current density of 10 mA cm^-2.The outstanding electrocatalytic activity may be ascribed to the improved conductivity and intrinsic activity owing to phosphating and the doping of V element.In addition,the long-term stability of V-doped Co P has been obtained.Therefore,metal doping into transition metal-based phosphides may be a promising strategy for the remarkable bifunctional electrocatalyst for water splitting.展开更多
Anatase（TiO_2） has been widely used in photocatalysis. However, it can only absorb near-ultraviolet light with a wavelength below approximately 388 nm due to a wide band gap. Therefore a modification should be made ...Anatase（TiO_2） has been widely used in photocatalysis. However, it can only absorb near-ultraviolet light with a wavelength below approximately 388 nm due to a wide band gap. Therefore a modification should be made for anatase to increase its capability in utilizing more abundant visible light. We investigated the doped anatase with the most promising 3d transition metal elements, and the results showed that the visible light absorption intensity was increased significantly due to the reduced band gap and the cavitation effects. As compared to other 3d transition metals, Cu was found to be the most effective one in improving anatase photocatalytic effects. In addition, greater Cu concentration doped in the anatase increased the photocatalysis effects but reduced the anatase stability, therefore, an optimized Cu concentration should be considered to optimize the anatase photocatalysis activity.展开更多
Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS h...Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS have outstanding quality for different applications. Moreover, ZnS doped with various elements are creating a new era for both academic research and industrial applications. So, the optical properties of modified ZnS thin film will help us to find a suitable doping element for convenient deposition which may enhance the conductance and transmitting properties of the film. This review work has been carried out to explore the four-modification elements that constitute Cu, Ni, Co & Fe as descending order of atomic number corresponding to Zn, along with some potential applications considering the recent research work with other doping elements too such as Al, C, Pt etc. For example, FE, FET, Catalytic, Solar cell, Electroluminescence, Fuel cell, different sensors (Chemical sensors, Bio-sensors, Humidity sensors, light sensors, UV light sensors) and nanogenerators use ZnS thin film.展开更多
In order to achieve a modulator with broad bandwidth and perfect impedance match,a novel electro-optical modulator based on GeO2-doped silica waveguides on silicon substrate is designed.The finite element model of the...In order to achieve a modulator with broad bandwidth and perfect impedance match,a novel electro-optical modulator based on GeO2-doped silica waveguides on silicon substrate is designed.The finite element model of the whole electro-optical modulator is established by means of ANSYS.With the finite element method analysis,the performance of the novel modulator is predicted.The simulation reveals that the designed modulator operates with a product of 3 dB optical bandwidth and modulating length of 226.59 GHz·cm,and a characteristic impedance of 51.6 Ω at 1 550 nm wavelength.Moreover,the calculated electrical reflected power of coplanar waveguide electrode is below-20 dB in the frequency ranging from 45 MHz to 65 GHz.Therefore,the designed modulator has wide modulation bandwidth and perfect impedance match.展开更多
We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alka...We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alkaline earth metal elements results in structural expansion when they were doped into theα-Si3N4 lattice.Formation energies of the doped structures indicate that dopants prefer to occupy the interstitial site under the nitrogen-deficient environment,while substitute Si under the nitrogen-rich environment,which provides a guide to synthesizingα-Si3N4 with different doping types by controlling nitrogen conditions.For electronic structures,energy levels of the dopants appear in the bottom of the conduction band or the top of the valence band or the forbidden band,which reduces the bandgap ofα-Si3N4.展开更多
基金Funded by National Key Research and Development Program of China (No.2021YFA1600203)。
文摘A series of nitrogen-doped SrMoO_(4) with different Sr/N mole ratio (R=0,0.05,0.10,0.15,0.20,0.40,and 0.60) were synthesized using urea as the N source via the vapor-thermal method.The photocatalytic degradation ability of all samples was evaluated using methylene blue (MB) as a target contaminant.The band gaps of N-doped samples are all higher than that of pristine ones,which is only 3.12 eV.BET specific surface area S_(BET) and pore volume are increased due to the N doping.And the greater increase of S_(BET),the faster the photodegradation speed of methylene blue on SrMoO_(4).More specifically,the degradation efficiency of MB is improved up to 87%in 100 min.
基金TheprojectisfinanciallysupportedbytheScienceResearchFoundationofOrdnanceEngineeringCollege (No .yjjxm0 0 0 6 )
文摘The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi 3.8(CoMn) 1.2 on its electrochemical performances and performances at high temperatures were investigated.It is found that the addition of aluminum brings about a significant increase in the discharge capacity at high temperatures,and the capacity decay during repeated charge-discharge cycles and the self-discharge are both suppressed, while the rate capability decreases.The alloy containing zirconium exhibits a longer cycle life and a better rate capability,but a much lower discharge capacity.The addition of titanium improves the rate capability, but the capacity decreases greatly.An X-ray diffraction analysis indicates that a second phase exists in the alloy with additive Zr or Ti,which improves the discharge-rate characteristics,and the superior stability of the alloy with additive Al may be due to the expansion of lattice parameters and cell volume.
基金Project(2009K06_03) supported by the Scientific and Technological Program of Shaanxi Province,China
文摘Infrared emissivity was studied in Zn0.99M0.01O(M is Mn,Fe or Ni) and Zn1-xCoxO(x=0.01,0.02,0.03 and 0.04) powders synthesized by solid-state reaction at various temperatures.XRD patterns confirm the wurtzite structure of the prepared samples.No peaks of other phases arising from impurities are detected in Mn-and Co-doped ZnO,but the peaks of ZnFe2O4 and NiO are observed in Zn0.99Fe0.01O and Zn 0.99 Ni 0.01 O.The SEM observations indicate that with larger grain sizes than those of Zn0.99Fe0.01O and Zn0.99Ni0.01O,Co-doped ZnO exhibits smooth grain surfaces.The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.01O are much stronger than those in Co-doped ZnO.Co ions are dissolved into the ZnO lattice with Co2+ state from XPS spectra analysis.The infrared emissivity results imply that the emissivity of Zn0.99Ni0.01 O is the highest(0.829) and that of Zn 0.99 Co 0.01 O is the lowest(0.784) at 1 200 C.The emissivity of Zn0.99Co0.01O decreases to the minimum(0.752) at 1 150 C and then increases with growing calcination temperature.As the Co doping content grows,the emissivity of Co-doped ZnO calcined at 1 200 C falls to 0.758 in the molar fraction of 3% and then ascends.
基金financially supported by Shandong Provincial Key Research and Development Program, China (No. 2017GGX20140)Shandong Provincial Natural Science Foundation, China (Nos. ZR2014JL031 and ZR2018MEE016)
文摘The microstructures of doped tungsten deformed by multi-pass hot continuous rolling were investigated, and the stress and strain fields were simulated by finite element(FE) method. After the continuous rolling, the grains of the tungsten rod were refined, and the microhardness was improved; however, a ring region of abnormal grain growth was present at a distance of about 3/5 R(R is the radius of the rod) from the center of the cross section. FE modeling results showed that the equivalent residual strains were minimum around the region of abnormal grain growth; this was due to the release of strain energy by severe plastic deformation, leading a situation where the migration force of grain boundaries was higher than the pinning force of potassium bubbles. By decreasing the initial rolling temperature and rolling speeds, the inhomogeneity of the equivalent residual stain decreased, improving the microstructure uniformity of the doped tungsten.
基金financially supported by the National Natural Science Foundation of China(21776314)Major Program of Shandong Province Natural Science Foundation(ZR2018ZC0639)+2 种基金Shandong Provincial Natural Science Foundation(ZR2017MB059)the Fundamental Research Funds for the Central Universities(18CX05016A)Postgraduate Innovation Project of China University of Petroleum(YCX2018034)
文摘Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped CoP)nanoparticles has been investigated through a facile gaseous phosphorization using cobalt vanadium oxide or hydroxide(Co-V hydr(oxy)oxide)as precursor.The physical characterization shows that the homogeneous dispersion of V element on V-doped CoP nanoparticles have obtained,which may imply the enhanced electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The electrochemical measurements of the prepared V-doped CoP in alkaline electrolyte demonstrate the superior electrocatalytic activity for both HER(overpotential of 235 mV@10 mA cm^-2)and OER(overpotential of 340 mV@10 mA cm^-2).Further,V-doped CoP nanoparticles used as anode and cathode simultaneously in a cell require only 370 mV to achieve a current density of 10 mA cm^-2.The outstanding electrocatalytic activity may be ascribed to the improved conductivity and intrinsic activity owing to phosphating and the doping of V element.In addition,the long-term stability of V-doped Co P has been obtained.Therefore,metal doping into transition metal-based phosphides may be a promising strategy for the remarkable bifunctional electrocatalyst for water splitting.
基金Funded by the National Natural Science Foundation of China(Nos.51604205 and 51774223)the Natural Science Foundation of Hubei Province(No.2016CFB268)+1 种基金the Fundamental Research Funds for the Central Universities(WUT:2016IVA046 and 2017IVB018)the Open Fund from Hubei Key Laboratory of Indust rial Fume and Dust Pollution Control(HBIK2015-02)
文摘Anatase（TiO_2） has been widely used in photocatalysis. However, it can only absorb near-ultraviolet light with a wavelength below approximately 388 nm due to a wide band gap. Therefore a modification should be made for anatase to increase its capability in utilizing more abundant visible light. We investigated the doped anatase with the most promising 3d transition metal elements, and the results showed that the visible light absorption intensity was increased significantly due to the reduced band gap and the cavitation effects. As compared to other 3d transition metals, Cu was found to be the most effective one in improving anatase photocatalytic effects. In addition, greater Cu concentration doped in the anatase increased the photocatalysis effects but reduced the anatase stability, therefore, an optimized Cu concentration should be considered to optimize the anatase photocatalysis activity.
文摘Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS have outstanding quality for different applications. Moreover, ZnS doped with various elements are creating a new era for both academic research and industrial applications. So, the optical properties of modified ZnS thin film will help us to find a suitable doping element for convenient deposition which may enhance the conductance and transmitting properties of the film. This review work has been carried out to explore the four-modification elements that constitute Cu, Ni, Co & Fe as descending order of atomic number corresponding to Zn, along with some potential applications considering the recent research work with other doping elements too such as Al, C, Pt etc. For example, FE, FET, Catalytic, Solar cell, Electroluminescence, Fuel cell, different sensors (Chemical sensors, Bio-sensors, Humidity sensors, light sensors, UV light sensors) and nanogenerators use ZnS thin film.
基金Supported by National Natural Science Foundation of China (No.60577023)Key Laboratory of Opto-Electronics Information and Technical Science of Ministry of Education,China
文摘In order to achieve a modulator with broad bandwidth and perfect impedance match,a novel electro-optical modulator based on GeO2-doped silica waveguides on silicon substrate is designed.The finite element model of the whole electro-optical modulator is established by means of ANSYS.With the finite element method analysis,the performance of the novel modulator is predicted.The simulation reveals that the designed modulator operates with a product of 3 dB optical bandwidth and modulating length of 226.59 GHz·cm,and a characteristic impedance of 51.6 Ω at 1 550 nm wavelength.Moreover,the calculated electrical reflected power of coplanar waveguide electrode is below-20 dB in the frequency ranging from 45 MHz to 65 GHz.Therefore,the designed modulator has wide modulation bandwidth and perfect impedance match.
基金Funded by National Key Research and Development Program of China(No.2017YFB0310400)the National Natural Science Foundation of China(Nos.51872217,51932006,51972246 and 51521001)+3 种基金Fundamental Research Funds for the Central Universities in ChinaState Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology),the Joint Fund(No.6141A02022255)the Major Program of the Specialized Technological Innovation of HuBei Province,China(No.2019AFA176)the“111”Project(No.B13035)。
文摘We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alkaline earth metal elements results in structural expansion when they were doped into theα-Si3N4 lattice.Formation energies of the doped structures indicate that dopants prefer to occupy the interstitial site under the nitrogen-deficient environment,while substitute Si under the nitrogen-rich environment,which provides a guide to synthesizingα-Si3N4 with different doping types by controlling nitrogen conditions.For electronic structures,energy levels of the dopants appear in the bottom of the conduction band or the top of the valence band or the forbidden band,which reduces the bandgap ofα-Si3N4.
