A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary...A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.展开更多
In order to explore an "anomalous" conduction phenomenon in the system Zn(1-x)FeCrO4Nix which was investigated with Mossbauer spectra, X-rays diffraction, Infrared spectra and other methods. The results show...In order to explore an "anomalous" conduction phenomenon in the system Zn(1-x)FeCrO4Nix which was investigated with Mossbauer spectra, X-rays diffraction, Infrared spectra and other methods. The results show that the conductivity anomaly is not an intrinsic behavior but arises from the moisture-adsorption. Their native conduction is similar to that of semiconductors, obeying the relationship σ= σ∞ exp (Ea/KT). All samples crystallize in cubic symmetry and their lattice parameters increase with x. The cation distribution is ( Zn(1-x)Fex) [Fe(1-x)NixCr]O4 No phase change occurs in the temperature range from 283 to 423 K.展开更多
Semiconductor(Zn\-\%x\%Cd 1-x S) doped silica glasses were prepared by Sol_Gel process and \%in situ\% growth technique. The structure of the materials was characterized by X_ray diffraction technique, the particle si...Semiconductor(Zn\-\%x\%Cd 1-x S) doped silica glasses were prepared by Sol_Gel process and \%in situ\% growth technique. The structure of the materials was characterized by X_ray diffraction technique, the particle size of semiconductor crystallites from X_ray patterns was estimated less than 10 nm. From absorption spectra, it is obtained that the absorption edges shifted to short wavelength diraction when Zn contents increased, and the absorption edge can be adjusted from 2.46 eV to 2.96 eV by controlling Zn contents. The third_order nonlinear optical susceptibility was studied at 532 nm with 8 ns pulse laser by degenerate four wave mixing (DFWM) technique.展开更多
The different compositions of the ternary alloyed CdSe_(x)S_(1-x)quantum dots(QDs)and CdSe_(x)S_(1-x)/ZnS core/shell quantum dots(CSQDs)have been synthesized by the chemical routes.The radii of these QDs were determin...The different compositions of the ternary alloyed CdSe_(x)S_(1-x)quantum dots(QDs)and CdSe_(x)S_(1-x)/ZnS core/shell quantum dots(CSQDs)have been synthesized by the chemical routes.The radii of these QDs were determined by transmission electron microscope(TEM).The optical properties of these QDs were investigated by the absorption and fluorescent measurement.It was found that the absorption and fluorescent emissions were tuned by the component ratio,and the Commission Internationale de l´Eclairage(CIE)coordinates of the fluorescent spectra also depended on the composition.Compared with the CdSe_(x)S_(1-x)QDs,the CdSe_(x)S_(1-x)/ZnS CSQDs exhibit the fluorescence enhancement due to the surface passivation by shell coating.The composition-tuned optical properties may allow them to be used as fluorescent markers in biological imaging and to fabricate multicolor light emitting diode(LED).展开更多
基金Funded by the Open Project Program of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(No.KLIFMD201606)the Open Fund of National Innovation Platform(No.2017YJ163)+1 种基金the National Natural Science Foundation of China(Nos.51502220,51521001,and 51672197)the Open Foundation of Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics(Wuhan University of Technology)(No.TAM201802)。
文摘A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.
文摘In order to explore an "anomalous" conduction phenomenon in the system Zn(1-x)FeCrO4Nix which was investigated with Mossbauer spectra, X-rays diffraction, Infrared spectra and other methods. The results show that the conductivity anomaly is not an intrinsic behavior but arises from the moisture-adsorption. Their native conduction is similar to that of semiconductors, obeying the relationship σ= σ∞ exp (Ea/KT). All samples crystallize in cubic symmetry and their lattice parameters increase with x. The cation distribution is ( Zn(1-x)Fex) [Fe(1-x)NixCr]O4 No phase change occurs in the temperature range from 283 to 423 K.
文摘Semiconductor(Zn\-\%x\%Cd 1-x S) doped silica glasses were prepared by Sol_Gel process and \%in situ\% growth technique. The structure of the materials was characterized by X_ray diffraction technique, the particle size of semiconductor crystallites from X_ray patterns was estimated less than 10 nm. From absorption spectra, it is obtained that the absorption edges shifted to short wavelength diraction when Zn contents increased, and the absorption edge can be adjusted from 2.46 eV to 2.96 eV by controlling Zn contents. The third_order nonlinear optical susceptibility was studied at 532 nm with 8 ns pulse laser by degenerate four wave mixing (DFWM) technique.
基金supported by the National Natural Science Foundation of China(No.11204214)the Teaching Reform Project of Tianjin University of Technology(No.ZX20-05)
文摘The different compositions of the ternary alloyed CdSe_(x)S_(1-x)quantum dots(QDs)and CdSe_(x)S_(1-x)/ZnS core/shell quantum dots(CSQDs)have been synthesized by the chemical routes.The radii of these QDs were determined by transmission electron microscope(TEM).The optical properties of these QDs were investigated by the absorption and fluorescent measurement.It was found that the absorption and fluorescent emissions were tuned by the component ratio,and the Commission Internationale de l´Eclairage(CIE)coordinates of the fluorescent spectra also depended on the composition.Compared with the CdSe_(x)S_(1-x)QDs,the CdSe_(x)S_(1-x)/ZnS CSQDs exhibit the fluorescence enhancement due to the surface passivation by shell coating.The composition-tuned optical properties may allow them to be used as fluorescent markers in biological imaging and to fabricate multicolor light emitting diode(LED).
