YAG： Ce^3 ＋ phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some interm...YAG： Ce^3 ＋ phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some intermediate phases, including θ-Al2O3, YAM and YAP, are formed when calcining polyacrylamide gel, however, the pure YAG phase can be formed directly when calcining polyacrylamide gel with α-Al2O3 as seed crystal. These facts show that the existence of α- Al2O3 seed crystal can block the formation of θ-Al2O3, YAM and YAP, and accelerate its reaction with Y2O3 to form YAG phase directly at lower temperature. The emission peak of prepared YAG ： Ce^3 ＋ phosphor is wide with maximum at 550 nm and the exitation band has two peaks, the major one is around at 460 nm, which matches the blue emission of GaN LED and is suitable for the assemble of white LED. Some fluxes can enhance the photoluminescence intensity of phosphor particles, that can be attributed both to the improvement of crystallization processes of YAG and to the stabilization of trivalence cerium ion in YAG：Ce^3 ＋.展开更多
The microstructure of Cr_(25)Ni_(20)stainless steel under plastic deformation up to 50% has re- vealed an even distributed twins,micro-twins and deformation bands.The σ-phase formation in 800℃ aged specimens is acce...The microstructure of Cr_(25)Ni_(20)stainless steel under plastic deformation up to 50% has re- vealed an even distributed twins,micro-twins and deformation bands.The σ-phase formation in 800℃ aged specimens is accelerated by its nucleation at either deformation twins or recrystallized grain boundaries under less or more deformation respectively.In the recrystallized zone,the recrystallization is prior to the precipitation of σ-phase.Although recrystallization may accelerate the formation of σ-phase,it is not essential.The twins and micro-twins produced by deformation may also provide the additional nucleation sites.展开更多
Finite difference method was used to calculate the macroscopic transportation phenomena(including temperature and concentration fields) of Al 7%Si(mass fraction) alloy. On the basis of the results,coupled with local a...Finite difference method was used to calculate the macroscopic transportation phenomena(including temperature and concentration fields) of Al 7%Si(mass fraction) alloy. On the basis of the results,coupled with local area magnification, the nucleation and growth of primary α phase of Al 7%Si were simulated. Relating the growth process of α phase of Al 7%Si alloy in space with structures of a sample section, the morphology and precipitating process of primary α phase of Al 7%Si alloy was simulated. The results are in good agreement with those obtained experimentally.展开更多
The effects of stretching ratio and stretching temperature on pbase transition of melt-spun poly （ vinylidene fluoride ） fibers were investigated and analyzed by using scanning electron microscopy, wide angle X- ray...The effects of stretching ratio and stretching temperature on pbase transition of melt-spun poly （ vinylidene fluoride ） fibers were investigated and analyzed by using scanning electron microscopy, wide angle X- ray diffraction, differential scanning calorimetry and Fourier transfer infrared spectroscopy. The β phase exists in the as-spun fiber. The β phase content increases as the stretching ratio increases. When the stretching temperature is lower than 100 ℃ , enhancing temperature is good for the transition of phase a to ft. By contrast, when the stretching temperature is higher than 100 ℃ , enhancing temperature is unfavourable for the transition of phase a to β. Increasing the draw temperature increases the α-phase content.展开更多
Pure W and W-Cu-W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The α-β phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray dif...Pure W and W-Cu-W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The α-β phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray diffraction. They are directly related to the film microstructure, density and adhesion. Therefore, control of the film stress and phase component transition is essential for its applications. The phase component transition from β-W to α-W and intragranular stress evolution from tensile to compressive strongly depend on the deposition parameters and can be induced by lowering Ar pressure and rising target power. The compressively stressed films with α-W phase have a dense microstructure and high adhesion to Fe substrate.展开更多
Synthesis of aminoarylacetic acids with good yield in the presence of phase transfercatalyst (PTC) under sonication has been studied. Results obtained are superior to those by othersimilar methods. The data show that ...Synthesis of aminoarylacetic acids with good yield in the presence of phase transfercatalyst (PTC) under sonication has been studied. Results obtained are superior to those by othersimilar methods. The data show that cyclodextrin (5 -CD) is a more efficient catalyst thanother PTC. Optimum reaction conditions and a preliminary mechanism are also discussed.展开更多
A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorp...A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 μg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring(SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, longer lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water.展开更多
We show an example of a bounded potential on the half-line obtained as the image of an Inverse Transformation Operator of the Bessel singular potential of the Reduced Radial Schrödinger Equation, and show us ...We show an example of a bounded potential on the half-line obtained as the image of an Inverse Transformation Operator of the Bessel singular potential of the Reduced Radial Schrödinger Equation, and show us the Estimates of the A(α) amplitude.展开更多
We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylati...We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylation reaction and selenoxide syn-elimimation, which ensures the purity of the products.展开更多
The spark plasma sintering （SPS） was applied to prepare α-Si3 N4 ceramics of different densities with magnesia, silicon dioxide, alumina as the sintering aids. The mechanism of liquid phase sintering （LPS） wus d...The spark plasma sintering （SPS） was applied to prepare α-Si3 N4 ceramics of different densities with magnesia, silicon dioxide, alumina as the sintering aids. The mechanism of liquid phase sintering （LPS） wus discussed and the factors influencing the density of the prepared samples were analyzed. The dielectric constant of sintered samples was tested. The experimental results show that the density can be controlled from 2.48 g/ cm^3 to 3.09 g/ cm^3 while the content of the sintering aids and the sintering temperature alter and the dielectric constant is closely dependent on the density of obtained samples.展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities,China(No.2020CDJDPT001)the Chongqing Natural Science Foundation,China(No.cstc2021jcyj-msxm X0699)。
文摘YAG： Ce^3 ＋ phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some intermediate phases, including θ-Al2O3, YAM and YAP, are formed when calcining polyacrylamide gel, however, the pure YAG phase can be formed directly when calcining polyacrylamide gel with α-Al2O3 as seed crystal. These facts show that the existence of α- Al2O3 seed crystal can block the formation of θ-Al2O3, YAM and YAP, and accelerate its reaction with Y2O3 to form YAG phase directly at lower temperature. The emission peak of prepared YAG ： Ce^3 ＋ phosphor is wide with maximum at 550 nm and the exitation band has two peaks, the major one is around at 460 nm, which matches the blue emission of GaN LED and is suitable for the assemble of white LED. Some fluxes can enhance the photoluminescence intensity of phosphor particles, that can be attributed both to the improvement of crystallization processes of YAG and to the stabilization of trivalence cerium ion in YAG：Ce^3 ＋.
文摘The microstructure of Cr_(25)Ni_(20)stainless steel under plastic deformation up to 50% has re- vealed an even distributed twins,micro-twins and deformation bands.The σ-phase formation in 800℃ aged specimens is accelerated by its nucleation at either deformation twins or recrystallized grain boundaries under less or more deformation respectively.In the recrystallized zone,the recrystallization is prior to the precipitation of σ-phase.Although recrystallization may accelerate the formation of σ-phase,it is not essential.The twins and micro-twins produced by deformation may also provide the additional nucleation sites.
文摘Finite difference method was used to calculate the macroscopic transportation phenomena(including temperature and concentration fields) of Al 7%Si(mass fraction) alloy. On the basis of the results,coupled with local area magnification, the nucleation and growth of primary α phase of Al 7%Si were simulated. Relating the growth process of α phase of Al 7%Si alloy in space with structures of a sample section, the morphology and precipitating process of primary α phase of Al 7%Si alloy was simulated. The results are in good agreement with those obtained experimentally.
基金Funded by the Tianjin Natural Science Foundation ( No.003602611)
文摘The effects of stretching ratio and stretching temperature on pbase transition of melt-spun poly （ vinylidene fluoride ） fibers were investigated and analyzed by using scanning electron microscopy, wide angle X- ray diffraction, differential scanning calorimetry and Fourier transfer infrared spectroscopy. The β phase exists in the as-spun fiber. The β phase content increases as the stretching ratio increases. When the stretching temperature is lower than 100 ℃ , enhancing temperature is good for the transition of phase a to ft. By contrast, when the stretching temperature is higher than 100 ℃ , enhancing temperature is unfavourable for the transition of phase a to β. Increasing the draw temperature increases the α-phase content.
文摘Pure W and W-Cu-W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The α-β phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray diffraction. They are directly related to the film microstructure, density and adhesion. Therefore, control of the film stress and phase component transition is essential for its applications. The phase component transition from β-W to α-W and intragranular stress evolution from tensile to compressive strongly depend on the deposition parameters and can be induced by lowering Ar pressure and rising target power. The compressively stressed films with α-W phase have a dense microstructure and high adhesion to Fe substrate.
文摘Synthesis of aminoarylacetic acids with good yield in the presence of phase transfercatalyst (PTC) under sonication has been studied. Results obtained are superior to those by othersimilar methods. The data show that cyclodextrin (5 -CD) is a more efficient catalyst thanother PTC. Optimum reaction conditions and a preliminary mechanism are also discussed.
文摘A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 μg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring(SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, longer lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water.
文摘We show an example of a bounded potential on the half-line obtained as the image of an Inverse Transformation Operator of the Bessel singular potential of the Reduced Radial Schrödinger Equation, and show us the Estimates of the A(α) amplitude.
基金the National Natural Science Foundation of China(No.20332060)the Natural Science Foundation of Zhejiang Province(No.Y405407).
文摘We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylation reaction and selenoxide syn-elimimation, which ensures the purity of the products.
文摘The spark plasma sintering （SPS） was applied to prepare α-Si3 N4 ceramics of different densities with magnesia, silicon dioxide, alumina as the sintering aids. The mechanism of liquid phase sintering （LPS） wus discussed and the factors influencing the density of the prepared samples were analyzed. The dielectric constant of sintered samples was tested. The experimental results show that the density can be controlled from 2.48 g/ cm^3 to 3.09 g/ cm^3 while the content of the sintering aids and the sintering temperature alter and the dielectric constant is closely dependent on the density of obtained samples.
