A novel carbon fiber pretreatment was proposed.Polyacrylonitrile(PAN)-based carbon fibers were first anodized in H3PO4 electrolyte to achieve an active surface,and then coated with Mo-B catalysts by immersed the carbo...A novel carbon fiber pretreatment was proposed.Polyacrylonitrile(PAN)-based carbon fibers were first anodized in H3PO4 electrolyte to achieve an active surface,and then coated with Mo-B catalysts by immersed the carbon fibers in a uniformly dispersed Mo-B sol.The as-treated carbon fibers were then graphitized at 2 400 ℃ for 2 h.The structural changes were characterized by X-ray diffractometry(XRD),Raman spectroscopy,scanning electron microscopy(SEM) and high-resolution transmission electronic microscopy(HRTEM).The results show that much better graphitization can be achieved in the presence of Mo-B,with an interlayer spacing(d002) of 0.335 8 nm and a crystalline size(Lc) of 28 nm.展开更多
Apatite-lanthanum silicate has attracted considerable interest in recent years due to its high oxide ion conductivity.In this paper,V-doped samples La10-xVx(SiO4) 6O3+x(0≤x≤1.5) were prepared by sol-gel method and t...Apatite-lanthanum silicate has attracted considerable interest in recent years due to its high oxide ion conductivity.In this paper,V-doped samples La10-xVx(SiO4) 6O3+x(0≤x≤1.5) were prepared by sol-gel method and the influences of V-dopant content on calcining temperature and conductivity were reported.The samples were characterized by thermal analysis(TG-DSC) ,X-ray diffraction(XRD) and scanning electron micrograph(SEM) . The apatite was obtained at 800°C,a relatively low temperature in comparison to 1500°C with the conventional solid-state method.The ceramic pellets sintered at 1200°C for 5 h showed a higher relative density than La9.33Si6O26 pellets sintered at 1400°C for 20 h.The conductivities of samples were measured by electrochemical impedance spectroscopy.The conductivity was improved with the increase of V-dopant content on La site.展开更多
Imaging the doping elements is doped TiO2 thin film. But it is critical for understanding the photocatalytic activity of still a challenge to characterize the interactions between the dopants and the TiO2 lattice at t...Imaging the doping elements is doped TiO2 thin film. But it is critical for understanding the photocatalytic activity of still a challenge to characterize the interactions between the dopants and the TiO2 lattice at the atomic level. Here, we use high angle annular dark- field/annular bright-field scanning transmission electron microscope （HAADF/ABF-STEM） combined with electron energy loss spectroscopy （EELS） to directly image the individual Cr atoms doped in anatase TiO2（001） thin film from [100] direction. The Cr dopants, which are clearly imaged through the atomic-resolution EELS mappings while can not be seen by HADDF/ABF-STEM, occupy both the substitutional sites of Ti atoms and the interstitial sites of TiO2 matrix. Most of them preferentially locate at the substitutional sites of Ti atoms. These results provide the direct evidence for the doping structure of Cr-doped A- TiO2 thin film at the atomic level and also prove the EELS mapping is an excellent technique for characterizing the doped materials.展开更多
W-doped Li4TisO12 in the form of Li4Ti4.95W0.osO12 was firstly synthesized via solid state reaction. X-ray diffraction （XRD） and scanning electron microscope （gEM） were employed to characterize the structure and m...W-doped Li4TisO12 in the form of Li4Ti4.95W0.osO12 was firstly synthesized via solid state reaction. X-ray diffraction （XRD） and scanning electron microscope （gEM） were employed to characterize the structure and morphology of Li4Ti4.psW0.05Ol2. W-doping does not change the phase composition and particle morphology, while remarkably improves its cycling stability at high charge/discharge rate. Li4Ti4.95W0.05O12 exhibits an excellent rate capability with a reversible capacity of 131.2 mA.h/g at 10C and even 118.6 mA.h/g at 20C. The substitution of W for Ti site can enhance the electronic conductivity of Li4TisO12 via the generation of mixing Ti4＋/Ti3＋, which indicates that Li4Ti4.psW0.05O12 is promising as a high rate anode for the lithium-ion batteries.展开更多
The influences of BaCu（B2O5） （BCB） addition on sintering, microstructure and microwave dielectric properties of Li2MgTi308 ceramics were investigated using X-ray diffractometry, scanning electron microscopy and mi...The influences of BaCu（B2O5） （BCB） addition on sintering, microstructure and microwave dielectric properties of Li2MgTi308 ceramics were investigated using X-ray diffractometry, scanning electron microscopy and microwave dielectric measurements. The experimental results show that a small amount of BaCu（B2O5） addition can effectively reduce the sintering temperature to 900℃, and induce only a limited degradation of the microwave dielectric properties. Typically, the best microwave dielectric properties of er24.5, Q×f =24 622 GHz, rf=4.2×10-6℃ -1 are obtained for 1.0% BCB-doped Li2MgTi3O8 ceramics sintered at 900℃ for 3 h. The BCB-doped Li2MgTi3O8 ceramics can be compatible with Ag electrode, which may be a strong candidate for low temperature co-fired ceramics applications.展开更多
This work was synthesized CaAl2O4 （calcium aluminate） doped with trivalent praseodymium ions. CaAl2O4 with praseodymium 1.0% and 0.5% were synthesized. The powders of aluminates were characterized by scanning electr...This work was synthesized CaAl2O4 （calcium aluminate） doped with trivalent praseodymium ions. CaAl2O4 with praseodymium 1.0% and 0.5% were synthesized. The powders of aluminates were characterized by scanning electron microscopy and luminescence spectrofluorimetry.CaAl2O4, praseodymium ions, luminescence doped with praseodymium ion that showed less porosity in its grain structure and luminescent transitions that are dependent on the wavelengths of excitation and showing both types of transitions both 5d-4f and 4f-4f.展开更多
Na-doped p-type ZnO thin films have been realized by DC reactive magnetron sputtering with a set of metal-Zn targets doped with various Na contents and under different substrate temperatures, respectively. Hall effect...Na-doped p-type ZnO thin films have been realized by DC reactive magnetron sputtering with a set of metal-Zn targets doped with various Na contents and under different substrate temperatures, respectively. Hall effect measurement, field-emission SEM, X-ray diffraction and optical transmission were carried out to investigate the effects of Na content and substrate temperature on the properties of p-type films. Results indicate that all the Na-doped ZnO films are strongly （002） oriented, and have an average transmittance -85 % in the visible region. Na-doped p-type ZnO films with good structural, electrical, and optical properties can only be obtained at an intermediate amount of Na content and under appropriate substrate temperature. At the optimal condition, the Na-doped p-type ZnO has the lowest resistivity of 13. 8 Ω· cm with the carrier concentration as high as 1.07 × 10^18 em^-3. The stability of the Na-doped p-type ZnO is also studied in this paper and it is found that the electrical properties keep stable in a period of one month.展开更多
Because of its economical and environmentally friendly characteristics, the warm mix asphalt(WMA) is widely used in pavement engineering. However, the lack of microscopic study of WMA brings difficulties in understand...Because of its economical and environmentally friendly characteristics, the warm mix asphalt(WMA) is widely used in pavement engineering. However, the lack of microscopic study of WMA brings difficulties in understanding of its mechanical behavior and mechanisms at macroscopic scale which finally hinders the enhancement of WMA's performance. Therefore, this article aims to use atomic force microscopy(AFM), a promising microscopic technique, to investigate the effects of wax-based warm mix agents on asphalt microstructures and micromechanical properties at different temperatures. For simplicity's sake, microcrystalline waxes are selected as an alternative of these wax-based additives. It is shown that the sample preparation method has a vital impact on the morphology of asphalt samples. The effects of microcrystalline wax on asphalt's mechanical properties can be well captured by AFM tests. Results show that the blending of #70, #80 and #90 microcrystalline waxes lowers the modulus(20—60 MPa) of Pen70 asphalt at 25 ℃ while increasing its adhesion force(5—20 n N). The results of this study may shed some light on the comprehension of the effects of wax-based additives on asphalt materials at macroscopic level which can help estimate and predict its actual performance.展开更多
Er3+-Yb3+ co-doped fiber of 2 m long is used as the laser gain medium. Two fiber lasers with different structures have been set up, one is the line cavity fiber laser with the dielectric mirror being replaced by an al...Er3+-Yb3+ co-doped fiber of 2 m long is used as the laser gain medium. Two fiber lasers with different structures have been set up, one is the line cavity fiber laser with the dielectric mirror being replaced by an all-fiber reflecting mirror,the other is the ring cavity all-fiber laser. Both set-ups have achieved lasing operation at the wavelength of 1.53 μm. Pumped by the 1 064 nm light from all-solid-state Nd ∶YAG laser, the two fiber lasers at 1 530 nm are operational. Their output powers are 7.8 mW and 2 mW with 130 mW and 160 mW pump powers.展开更多
Erbium-doped tellurite-based glasses （Er3＋：TeO2-ZnO-La203） are prepared by the conventional melt-quenching technique, and concentration-dependent luminescence properties of Er3＋ are investigated. A significant sp...Erbium-doped tellurite-based glasses （Er3＋：TeO2-ZnO-La203） are prepared by the conventional melt-quenching technique, and concentration-dependent luminescence properties of Er3＋ are investigated. A significant spectral broadening of the 1.53 μm fluorescence corresponding to 4113/2 4115/2 transition is observed, and the fluorescence decaying becomes a nearly exponential way with the increasing Er3＊concentration. Radiation trapping is evoked to explain the broadening of 4113/2 4115/2 emission line of Er3＋ ions. The optimum doping content of Er203 for 1.53 μm fluorescence emission is about 1.5 mol%.展开更多
Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated...Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated.It is also found that the Bi-related emission intensity can be enhanced by Yb3+co-doping at the excitation of 980 nm LD.It should be ascribed to the energy transfer from Yb3+to active Bi ions.The energy transfer processes are studied based on the Inokuti-Hirayama(I-H)model,and the energy transfer of electric dipole-dipole interaction is confirmed to be dominant in Bi/Yb co-doped glasses.展开更多
基金Project(2006CB600903) supported by the National Basic Research Program of China
文摘A novel carbon fiber pretreatment was proposed.Polyacrylonitrile(PAN)-based carbon fibers were first anodized in H3PO4 electrolyte to achieve an active surface,and then coated with Mo-B catalysts by immersed the carbon fibers in a uniformly dispersed Mo-B sol.The as-treated carbon fibers were then graphitized at 2 400 ℃ for 2 h.The structural changes were characterized by X-ray diffractometry(XRD),Raman spectroscopy,scanning electron microscopy(SEM) and high-resolution transmission electronic microscopy(HRTEM).The results show that much better graphitization can be achieved in the presence of Mo-B,with an interlayer spacing(d002) of 0.335 8 nm and a crystalline size(Lc) of 28 nm.
基金Supported by the Joint Funds of NSFC-Guangdong of China(U0834004)the Natural Science Foundation of Guangdong Province(06025657)
文摘Apatite-lanthanum silicate has attracted considerable interest in recent years due to its high oxide ion conductivity.In this paper,V-doped samples La10-xVx(SiO4) 6O3+x(0≤x≤1.5) were prepared by sol-gel method and the influences of V-dopant content on calcining temperature and conductivity were reported.The samples were characterized by thermal analysis(TG-DSC) ,X-ray diffraction(XRD) and scanning electron micrograph(SEM) . The apatite was obtained at 800°C,a relatively low temperature in comparison to 1500°C with the conventional solid-state method.The ceramic pellets sintered at 1200°C for 5 h showed a higher relative density than La9.33Si6O26 pellets sintered at 1400°C for 20 h.The conductivities of samples were measured by electrochemical impedance spectroscopy.The conductivity was improved with the increase of V-dopant content on La site.
基金supported by the Ministry of Science and Technology of China(No.2016YFA0200603 and No.2013CB834605)the"Strategic Priority Research Program"of CAS(No.XDB01020100)+1 种基金the National Natural Science Foundation of China(No.91421313,No.21421063,and No.21573207)Anhui Provincial Natural Science Foundation(1708085MA06)
文摘Imaging the doping elements is doped TiO2 thin film. But it is critical for understanding the photocatalytic activity of still a challenge to characterize the interactions between the dopants and the TiO2 lattice at the atomic level. Here, we use high angle annular dark- field/annular bright-field scanning transmission electron microscope （HAADF/ABF-STEM） combined with electron energy loss spectroscopy （EELS） to directly image the individual Cr atoms doped in anatase TiO2（001） thin film from [100] direction. The Cr dopants, which are clearly imaged through the atomic-resolution EELS mappings while can not be seen by HADDF/ABF-STEM, occupy both the substitutional sites of Ti atoms and the interstitial sites of TiO2 matrix. Most of them preferentially locate at the substitutional sites of Ti atoms. These results provide the direct evidence for the doping structure of Cr-doped A- TiO2 thin film at the atomic level and also prove the EELS mapping is an excellent technique for characterizing the doped materials.
文摘W-doped Li4TisO12 in the form of Li4Ti4.95W0.osO12 was firstly synthesized via solid state reaction. X-ray diffraction （XRD） and scanning electron microscope （gEM） were employed to characterize the structure and morphology of Li4Ti4.psW0.05Ol2. W-doping does not change the phase composition and particle morphology, while remarkably improves its cycling stability at high charge/discharge rate. Li4Ti4.95W0.05O12 exhibits an excellent rate capability with a reversible capacity of 131.2 mA.h/g at 10C and even 118.6 mA.h/g at 20C. The substitution of W for Ti site can enhance the electronic conductivity of Li4TisO12 via the generation of mixing Ti4＋/Ti3＋, which indicates that Li4Ti4.psW0.05O12 is promising as a high rate anode for the lithium-ion batteries.
基金Project(2010GXNSFA013029) supported by the Natural Science Foundation of Guangxi Province,ChinaProject(101059529) supported by National Undergraduate Innovation Program of the Ministry of Education of China
文摘The influences of BaCu（B2O5） （BCB） addition on sintering, microstructure and microwave dielectric properties of Li2MgTi308 ceramics were investigated using X-ray diffractometry, scanning electron microscopy and microwave dielectric measurements. The experimental results show that a small amount of BaCu（B2O5） addition can effectively reduce the sintering temperature to 900℃, and induce only a limited degradation of the microwave dielectric properties. Typically, the best microwave dielectric properties of er24.5, Q×f =24 622 GHz, rf=4.2×10-6℃ -1 are obtained for 1.0% BCB-doped Li2MgTi3O8 ceramics sintered at 900℃ for 3 h. The BCB-doped Li2MgTi3O8 ceramics can be compatible with Ag electrode, which may be a strong candidate for low temperature co-fired ceramics applications.
文摘This work was synthesized CaAl2O4 （calcium aluminate） doped with trivalent praseodymium ions. CaAl2O4 with praseodymium 1.0% and 0.5% were synthesized. The powders of aluminates were characterized by scanning electron microscopy and luminescence spectrofluorimetry.CaAl2O4, praseodymium ions, luminescence doped with praseodymium ion that showed less porosity in its grain structure and luminescent transitions that are dependent on the wavelengths of excitation and showing both types of transitions both 5d-4f and 4f-4f.
基金Natural Science Foundation (60576063)Science and Technology Project of Zhejiang province(2008F70015)
文摘Na-doped p-type ZnO thin films have been realized by DC reactive magnetron sputtering with a set of metal-Zn targets doped with various Na contents and under different substrate temperatures, respectively. Hall effect measurement, field-emission SEM, X-ray diffraction and optical transmission were carried out to investigate the effects of Na content and substrate temperature on the properties of p-type films. Results indicate that all the Na-doped ZnO films are strongly （002） oriented, and have an average transmittance -85 % in the visible region. Na-doped p-type ZnO films with good structural, electrical, and optical properties can only be obtained at an intermediate amount of Na content and under appropriate substrate temperature. At the optimal condition, the Na-doped p-type ZnO has the lowest resistivity of 13. 8 Ω· cm with the carrier concentration as high as 1.07 × 10^18 em^-3. The stability of the Na-doped p-type ZnO is also studied in this paper and it is found that the electrical properties keep stable in a period of one month.
基金financial support of the Education Department of Jiangsu Province under Grant No.JZ-007the Jiangsu Natural Science Foundation under Grant No.BK 20140111
文摘Because of its economical and environmentally friendly characteristics, the warm mix asphalt(WMA) is widely used in pavement engineering. However, the lack of microscopic study of WMA brings difficulties in understanding of its mechanical behavior and mechanisms at macroscopic scale which finally hinders the enhancement of WMA's performance. Therefore, this article aims to use atomic force microscopy(AFM), a promising microscopic technique, to investigate the effects of wax-based warm mix agents on asphalt microstructures and micromechanical properties at different temperatures. For simplicity's sake, microcrystalline waxes are selected as an alternative of these wax-based additives. It is shown that the sample preparation method has a vital impact on the morphology of asphalt samples. The effects of microcrystalline wax on asphalt's mechanical properties can be well captured by AFM tests. Results show that the blending of #70, #80 and #90 microcrystalline waxes lowers the modulus(20—60 MPa) of Pen70 asphalt at 25 ℃ while increasing its adhesion force(5—20 n N). The results of this study may shed some light on the comprehension of the effects of wax-based additives on asphalt materials at macroscopic level which can help estimate and predict its actual performance.
文摘Er3+-Yb3+ co-doped fiber of 2 m long is used as the laser gain medium. Two fiber lasers with different structures have been set up, one is the line cavity fiber laser with the dielectric mirror being replaced by an all-fiber reflecting mirror,the other is the ring cavity all-fiber laser. Both set-ups have achieved lasing operation at the wavelength of 1.53 μm. Pumped by the 1 064 nm light from all-solid-state Nd ∶YAG laser, the two fiber lasers at 1 530 nm are operational. Their output powers are 7.8 mW and 2 mW with 130 mW and 160 mW pump powers.
基金supported by the National Natural Science Foundation of China(No.61178063)the Graduate Innovative Scientific Research Project of Zhejiang Province(No.YK2010048)+2 种基金the Natural Science Foundation of Ningbo City(No.2010A610172)the K.C.Wong Magna Fundthe Hu Lan Outstanding Doctoral Fund in Ningbo University
文摘Erbium-doped tellurite-based glasses （Er3＋：TeO2-ZnO-La203） are prepared by the conventional melt-quenching technique, and concentration-dependent luminescence properties of Er3＋ are investigated. A significant spectral broadening of the 1.53 μm fluorescence corresponding to 4113/2 4115/2 transition is observed, and the fluorescence decaying becomes a nearly exponential way with the increasing Er3＊concentration. Radiation trapping is evoked to explain the broadening of 4113/2 4115/2 emission line of Er3＋ ions. The optimum doping content of Er203 for 1.53 μm fluorescence emission is about 1.5 mol%.
基金supported by the National Natural Science Foundation of China(Nos.51272109and50972061)the Natural Science Foundation of Zhejiang Province(Nos.R4100364and Z4110072)+1 种基金the Natural Science Foundation of Ningbo City in Zhejiang Province(No.2012A610115)K.C.Wong Magna Fund in Ningbo University
文摘Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated.It is also found that the Bi-related emission intensity can be enhanced by Yb3+co-doping at the excitation of 980 nm LD.It should be ascribed to the energy transfer from Yb3+to active Bi ions.The energy transfer processes are studied based on the Inokuti-Hirayama(I-H)model,and the energy transfer of electric dipole-dipole interaction is confirmed to be dominant in Bi/Yb co-doped glasses.
