The compound ingots of Pr0.15TbxDy0.85-xFe2 (x=0 to 0.85) were prepared by arc melting in a water Cu boat using arc furnace under a purified Ar atmosphere. Appropriate annealing (850℃, 100 h) can obtain single Laves ...The compound ingots of Pr0.15TbxDy0.85-xFe2 (x=0 to 0.85) were prepared by arc melting in a water Cu boat using arc furnace under a purified Ar atmosphere. Appropriate annealing (850℃, 100 h) can obtain single Laves phase compound. The magnetostriction for these systems will rise obviously when partially substituted Tb or Dy by Pr.展开更多
Nanometer micro-porous Nix Zn (1-x )Fe2O4power was synthesized by hydrotherm al method.This is first time to apply template to the synthesis.The structure,characteristics and cry stal appearance are studied further by...Nanometer micro-porous Nix Zn (1-x )Fe2O4power was synthesized by hydrotherm al method.This is first time to apply template to the synthesis.The structure,characteristics and cry stal appearance are studied further by XRD,DSC,TEM,etc.It is found that nanome ter micro-porous crystal is well-crystallized,well-degree of dispers ion and smaller than 100nm in diameter.More over,tri-ethylamine can be used to b e a ideal template in this synthesis,and the first time it is reported in our co untry.The synthesis mechanism is also preliminary discussed in this pap er.展开更多
SMnxZn1-xFe2O4 （x=1,0.9,0.8,0.7,0.6,0.5,0.25,0） nanoparticles were prepared by ball-milling hydrothermal and investigated by X-ray diffraction, DTG and TEM. Nanocrystallite grain size was determined by X-ray linewid...SMnxZn1-xFe2O4 （x=1,0.9,0.8,0.7,0.6,0.5,0.25,0） nanoparticles were prepared by ball-milling hydrothermal and investigated by X-ray diffraction, DTG and TEM. Nanocrystallite grain size was determined by X-ray linewidth to be from 63 A to 274 A. The thermal properties indicate absorbed water still remain at low temperature, crystalline wate will be decomposed from 230 ℃ to 260 ℃, partial Mn^2＋ will be oxidized near 730 ℃. TEM shows the ferrite particles pocess a spherical morphology and uniform nanosize.展开更多
It is reported the first time that the CoxNi(1-x)Fe2O4(0≤x≤1) catalyst prepared under microwave radiation is more active for H2O2 decomposition than that prepared by conventional heating,and this tendency becomes mo...It is reported the first time that the CoxNi(1-x)Fe2O4(0≤x≤1) catalyst prepared under microwave radiation is more active for H2O2 decomposition than that prepared by conventional heating,and this tendency becomes more manifested,as x increases in CoxNi(1-x)Fe2Oe.展开更多
Co-precipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases, it can be exploited. The Zn0.5Mn0.5−xLi2xFe2O4 nanomaterials (x = 0.0, 0.1, 0.2, 0.3 and 0.4) wa...Co-precipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases, it can be exploited. The Zn0.5Mn0.5−xLi2xFe2O4 nanomaterials (x = 0.0, 0.1, 0.2, 0.3 and 0.4) was afforded by utilizing co-precipitation method. The structural and optical characteristics were analyzed for the samples employing X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and Ultraviolet-visible spectrophotometer (UV-Vis). XRD revealed that the structure of certain nanoparticles is a cubic spinel with space group (Fd-3m) and crystallite size in the scale 124 - 150 nm. Lattice parameter was determined to increments with Li+1 and that may occur due to the larger ionic radius of the Li1+ ion. FTIR spectroscopy confirmed the form of spinel ferrite and explicated the properties of absorption bands approximately 593, 1111, 1385, 1640, 2922 and 3430. The energy band gap was estimated for all samples with diverse ratios and was observed in the range of 2.58 - 2.52 eV.展开更多
Low-frequency resistance noise spectroscopy is applied to investigate bulk single crystals of the intercalated ironselenide K_(x)Fe_(2-y)Se_(2) superconductors with different iron vacancy orders.Based on a generalized...Low-frequency resistance noise spectroscopy is applied to investigate bulk single crystals of the intercalated ironselenide K_(x)Fe_(2-y)Se_(2) superconductors with different iron vacancy orders.Based on a generalized fluctuation model,the well-observed resistance hump above 100 K is interpreted as an insulator-metal phase transition with a characteristic transition energy of 0.1-0.6 eV,indicating a highly inhomogeneous energy distribution configuration.In the superconducting transition regime,we find that the normalized resistance noise scales with resistance R excellently as S_(R)/R^(2)∝R^(l_(rs)) with the noise exponent lrs≈1.4.With reduced iron vacancy disordering in enhanced superconductivity K_(x)Fe_(2-y)Se_(2) crystals,the level of resistance fluctuations is greatly suppressed,suggesting a geometrical phase transition for conduction channel,which is directly related to the microstructure of the crystals.展开更多
基金the Natural Science Foundation of Hebei Province 596028 and the National NaturalScience Foundation of China No.59871062.
文摘The compound ingots of Pr0.15TbxDy0.85-xFe2 (x=0 to 0.85) were prepared by arc melting in a water Cu boat using arc furnace under a purified Ar atmosphere. Appropriate annealing (850℃, 100 h) can obtain single Laves phase compound. The magnetostriction for these systems will rise obviously when partially substituted Tb or Dy by Pr.
文摘Nanometer micro-porous Nix Zn (1-x )Fe2O4power was synthesized by hydrotherm al method.This is first time to apply template to the synthesis.The structure,characteristics and cry stal appearance are studied further by XRD,DSC,TEM,etc.It is found that nanome ter micro-porous crystal is well-crystallized,well-degree of dispers ion and smaller than 100nm in diameter.More over,tri-ethylamine can be used to b e a ideal template in this synthesis,and the first time it is reported in our co untry.The synthesis mechanism is also preliminary discussed in this pap er.
基金Basic Research for Application of Sichuan Province(No.05JY029-071-2)
文摘SMnxZn1-xFe2O4 （x=1,0.9,0.8,0.7,0.6,0.5,0.25,0） nanoparticles were prepared by ball-milling hydrothermal and investigated by X-ray diffraction, DTG and TEM. Nanocrystallite grain size was determined by X-ray linewidth to be from 63 A to 274 A. The thermal properties indicate absorbed water still remain at low temperature, crystalline wate will be decomposed from 230 ℃ to 260 ℃, partial Mn^2＋ will be oxidized near 730 ℃. TEM shows the ferrite particles pocess a spherical morphology and uniform nanosize.
文摘It is reported the first time that the CoxNi(1-x)Fe2O4(0≤x≤1) catalyst prepared under microwave radiation is more active for H2O2 decomposition than that prepared by conventional heating,and this tendency becomes more manifested,as x increases in CoxNi(1-x)Fe2Oe.
文摘Co-precipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases, it can be exploited. The Zn0.5Mn0.5−xLi2xFe2O4 nanomaterials (x = 0.0, 0.1, 0.2, 0.3 and 0.4) was afforded by utilizing co-precipitation method. The structural and optical characteristics were analyzed for the samples employing X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and Ultraviolet-visible spectrophotometer (UV-Vis). XRD revealed that the structure of certain nanoparticles is a cubic spinel with space group (Fd-3m) and crystallite size in the scale 124 - 150 nm. Lattice parameter was determined to increments with Li+1 and that may occur due to the larger ionic radius of the Li1+ ion. FTIR spectroscopy confirmed the form of spinel ferrite and explicated the properties of absorption bands approximately 593, 1111, 1385, 1640, 2922 and 3430. The energy band gap was estimated for all samples with diverse ratios and was observed in the range of 2.58 - 2.52 eV.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11774303 and 11574373)Joint Fund of Yunnan Provincial Science and Technology Department,China(Grant No.2019FY003008)。
文摘Low-frequency resistance noise spectroscopy is applied to investigate bulk single crystals of the intercalated ironselenide K_(x)Fe_(2-y)Se_(2) superconductors with different iron vacancy orders.Based on a generalized fluctuation model,the well-observed resistance hump above 100 K is interpreted as an insulator-metal phase transition with a characteristic transition energy of 0.1-0.6 eV,indicating a highly inhomogeneous energy distribution configuration.In the superconducting transition regime,we find that the normalized resistance noise scales with resistance R excellently as S_(R)/R^(2)∝R^(l_(rs)) with the noise exponent lrs≈1.4.With reduced iron vacancy disordering in enhanced superconductivity K_(x)Fe_(2-y)Se_(2) crystals,the level of resistance fluctuations is greatly suppressed,suggesting a geometrical phase transition for conduction channel,which is directly related to the microstructure of the crystals.
