A series of non-rare earth Mn4+-activated strontium aluminate phosphors Sr4Al14O25:Mn4+co-doped with Sc3+ions were successfully synthesized by a high-temperature solid-state reaction method.XRD result reveals that there is no introduction of additional phase but expansion of lattice with incorporation of Sc34 ions.Excitation and emission spectrum measurement shows that the synthesized phosphors can be efficiently excited by near-ultraviolet and blue light,and a deep red emission centered at 652 nm with a narrow full width at half maximum(FWHM)can be obtained,which is attributed to the transition2E→4A2of Mn4+ions.In addition,the crystal field strength parameter(Dq)and Racah parameters(B,C)and energies of states were calculated based on experimental data.Moreover,the luminous intensity of Sr4Al14-xSCxO25:Mn4+is enhanced and increased by 60%compared with Mn4+single incorporated sample at x=0.06.A phenomenon of redshift is observed in the excitation spectrum and discussed systematically.Finally,the mechanism of the positive effects with Sc3+ions incorporated into lattice is discussed in detail.All the results suggest that the Sr4Al13.94Sc0.06O25:Mn4+phosphor will become one of the great candidates for backlight of LCD. 相似文献
To determine the flow behavior of SUS304 stainless steel under different conditions, axisymmetric compression tests were conducted over a wide range of forming temperatures (25 °C to 400 °C) and strain rates (10−3 to 10 s−1). Flow curves were obtained for different forming conditions to study the influence of the forming temperature and strain rate on the flow behavior. Moreover, electron backscatter diffraction analysis, X-ray diffraction analysis, transmission electron microscopy, and Feritscope were used to study the microstructure evolution of SUS304 stainless steel under different conditions for determining the underlying reasons for the variations in flow behavior. The experimental results indicated that the flow stress decreased with increasing the forming temperature. With increasing strain rate at 25 °C to 200 °C, the flow stress first increased and then decreased; however, the strain rate had little effect on the flow stress at 300 °C and 400 °C. By analyzing the variation in the phase transformation inside compressed SUS304 stainless steel samples under different forming conditions, the key factors affecting the flow behavior of stainless steel were identified. Finally, by examining the variation in the martensite content and the dislocation density, the dominant deformation mechanism under different forming conditions was determined.