Recently, lanthanides have been employed by researchers to examine their impact on the structure and properties of Li7La3Zr2O12 (LLZO) garnets. In this regard, we developed Europium oxide (Eu2O3) doped LLZO (Li7+δEuxLa3−δZr2−δO12−δ) solid electrolyte which demonstrates a cubic phase with the symmetry of Iad (No.230) at room temperature. In this investigation, different concentrations of Eu ranging from 0.1 to 0.6 atoms per formula unit (pfu) were doped into Li7La3Zr2O12 to evaluate the impact of Eu on the stability of the cubic phase and thereby the ionic conductivity. The results unveiled that upon doping Eu3+ ions, the Eu2+ state is also formed and is then self-doped into the structure in which Rietveld refinement coupled with XPS, EPR, and solid-state NMR suggests that Eu3+ ions most probably partially occupy Zr4+ (16a) site, the Eu2+ ions occupy La3+ (24d) site, and the Li+ ions occupy two different sites (24d and 96h). It was further found that such a site preference induces distortion at LaO8 polyhedrons opening up the neck for Li-ions diffusion, thereby enhancing the ionic conductivity. Moreover, it was revealed that Li-ions probably hop from 96h to 24d and then to 96h site to generate the Li-ion movement. Overall, by introducing Eu ions into the LLZO structure, an enhanced bulk ionic conductivity of 0.30 × 10−3 S/cm at 298 K with a minimum electronic conductivity of 2.547 × 10−9 S/cm at 298 K was achieved. 相似文献
针对立方调频(Cubic Frequency Modulated,CFM)信号的参数估计问题,提出了一种基于高阶模糊函数(High order Ambiguity Function,HAF)和相参积累三阶自相关函数(Coherently Integrated Trilinear Autocorrelation Function,CITAF)的参数估计方法。利用HAF将立方相位信号降阶为二次调频(Quadratic Frequency Modulated,QFM)信号,再利用CITAF完成参数估计。由于CITAF能够在时域和时延域完成信号能量的二维相参积累,其实现过程利用复乘、傅里叶变换和加法操作即可完成,因此该方法能够提高参数估计的分辨率和抗噪声干扰能力,并保持较低的计算量。实验结果证实了该算法的有效性和性能上的优越性。 相似文献
In ISAR imaging for targets with the complex motion, since the azimuth high order phase terms caused by the time-varying rotation vector will deteriorate the azimuth focusing quality, the traditional RD algorithm and LFM model are not appropriate. Thereby, in the case when the received signal can be modeled as cubic phase signals (CPSs), this paper proposes an ISAR imaging algorithm based on HAF-LVD (high-order ambiguity function-Lv's distribution). First, this algorithm defines a novel double lag parametric instantaneous autocorrelation function, and then applies the scaling operator to remove the coupling and utilizes FFT to achieve the energy accumulation. Finally, the non-searching estimation of the moving parameter and the ISAR images for targets are accomplished by the obtained HAF-LVD. Because of the introduction of the scaling factor, this algorithm can flexibly deal with more changeful and hostile ISAR environment without loss of the anti-noise performance and computational efficiency. Simulation results validate the effectiveness of the ISAR imaging approach. 相似文献