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High ionic conductivity is usually observed in the cubic phase of garnet Li7La3Zr2O12 (LLZO), which can be stabilized by dopants including Ca2+, Fe3+, Al3+, Ga3+, Ti4+, and Si4+. However, the ionic conductivity shows a strong dependence on both the lithium and the dopant atomic occupancy of the garnet LLZO crystal structure (space group Ia-3d), i.e., the 24d (LiO4) or 96h (LiO6) sites. Dopants occupying the 24d site can induce a strong local electric field which blocks the Li+ diffusion path. By employing SPS (Spark Plasma Sintering) to improve Al-LLZO's electrochemical performance, the mechanism of phase evaluation and atomic occupancy grove electrochemical performance was revealed. In the first study, high energy in the SPS induces Al3+ diffusion in LLZO lattices, transforming tetragonal phase LLZO into cubic phase LLZO. The Inter- and intra-grain effects on the ionic conductivity of LLZO SSE are discussed. As a result of the removal of low-conductivity impurities and an increase in bulk density, inter-grain ionic conductivity increases. In addition, the superior intra-grain ionic conductivity correlates with an increasing trend in LLZO SSE and an apparent decrease in secondary phase content. A rise in 24dLi1/96hLi2 occupancy ratio and a decrease in 24dAl1/96hAl2 correlates with increased ionic conductivity within the LLZO lattice. After SPS treated at 1100 oC, the ionic conductivity of LLZO prepared by SPS can reach 2.6×10-4 S cm-1, and the electronic conductivity is maintained at a low level. Moreover, this study provides insight into the relationship and correlation between two major factors (phase evaluation and atomic occupation) and ionic conductivity. However, the sparking plasma sintering (SPS) process, which limits the diffusion and relaxation time of the material, introduces a metastable state of the cubic LLZO with strong lattice distortion and inadequate ion distribution. In the second study, post-annealing promotes ion rearrangement, especially the Al3+ migration from the 24d to 96h sites, which is driven by the mitigation of the metastable state as identified by structure and composition analysis. Ionic conductivity as high as 3.3×10-4 S cm-1 is achieved along with low electronic conductivity of 5.17×10-7 S cm-1 by post-annealing at 500 oC in an oxygen environment after the SPS process. This work demonstrated a strategy to fabricate LLZO solid-state electrolyte with high ionic conductivity by manipulating its metastable state. It revealed that atomic occupation is a vital factor in influencing ionic conductivity besides doping content and bulk density. In addition, this work also prepared Ga and Ta doped LLZO powder and the effects of Ga and Ta substitutions on sintering have been meticulously studied. LLZO can be doped with Ga3+ and Ta5+ to achieve cubic crystal structure. The crystal structure is adjusted by Ga3+ substitution at Li+ sites and Ta5+ substitution at Zr4+.

The comprehensive control platform of a simulator is the control center of a hardware in the loop simulation system, whose key technologies are timing precision and timing data synchronization. This paper achieves the precise timing using the high-precision timer under a real-time extension(RTX) system, designs the driving program of VMIC card under the RTX system, studies the data synchronization algorithm, its flow chart and the method for designing the software of the comprehensive control platform. The study results indicate preliminarily that the hardware in the loop simulation system can achieve precise timing, does not produce erroneous frames or lose any frames, ensures its synchronization of data transmission and thus is worth applying to the development of a missile weapon system

A stratospheric satellite flies from east to west around the earth in the stratosphere, and a certain number of stratospheric satellites make up the global stratospheric balloon constellation. This paper presents the stratospheric satellite's trajectory control method. It also describes the working principles, component parts and functions of the stratospheric satellite. To establish the model of its trajectory control system, the paper defines its various coordinate systems and analyzes the stress of the super-pressure helium balloon and that of the stratosail. It then presents the scheme of the trajectory control system. Finally, it carries out the numerical simulation to verify the effectiveness of the trajectory control method. The simulation results, given in Fig. 7, show preliminarily that: (1) the stratosail can exert the stable control of the movement of the stratospheric satellite along its orbit from north to south; (2) Under the interference of 5 m/s wind, with the control of the stratosail, the maximum distance of the super-pressure balloon away from its orbit is about 700m, but it takes around 10000 s to adjust the distance.