分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： The chlorination of rare earth oxides by MgCl2 was investigated in the molten chlorides. To reduce the solvent salt volatility, the LiCl-NaCl mixture was selected as a solvent by comparing the mass loss of the LiCl-NaCl with LiCl-KCl melts after the addition of MgCl2 in the temperature range of 873 K to 1073 K. The dissolution behavior of La2O3 was investigated in the LiCl-NaCl-MgCl2 melts by XRD measurements and ICP-AES analysis of the melts, which indicated that La2O3 was chlorinated by MgCl2 to produce LaCl3. The reduction peak of La(III) in the LiCl-NaCl-MgCl2-La2O3 melts was observed from cyclic voltammogram and square wave voltammogram. The Mg-La alloy obtained by galvanostatic electrolysis in the LiCl-NaCl-MgCl2-La2O3 melts was characterized by XRD and SEM-EDS, indicating that the Mg-La alloy consisted of Mg and La2Mg17 phases.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： The reduction of Tm(III) on a liquid Zn electrode was investigated in a LiCl-KCl melt via cyclic voltammetry, square wave voltammetry, and open circuit chronopotentiometry. On a liquid Zn electrode, the reduction mechanism of Tm(III) ions is through one step with the exchange of three electrons via the formation of a Zn-Tm alloy. This differs from that on an inert electrode, as the reduction is Tm(III) ions were though two consecutive steps. Galvanostatic electrolysis was carried out at a liquid Zn electrode at different current densities in a LiCl-KCl-TmCl3 melt. The Tm2Zn17 intermetallic compound was identified in the deposit, except in the Zn phase, by X-ray Diffraction (XRD).
分类： 天文学 >> 天文学 提交时间： 2024-08-14 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： Active reflectors are often used to compensate the surface distortion caused by environmental factors that degrade the electromagnetic performance of large high-frequency reflector antennas. This is crucial for maintaining high gain operation in antennas. A distortion compensation method for the active reflector of a large dual-reflector antenna is proposed. A relationship is established between the surface deformation and the optical path difference for the primary reflector by geometric optics. Subsequently, employing finite element analysis, a polynomial fitting approach is used to describe the impact of adjusting points on the reflector surface based on the coordinates of each node. By standardizing the positions of various panels on the reflector, the fitting ns can be applied to the reflector panels of similar shapes. Then, based on the distribution characteristics of the primary reflector panels, the adjustment equation for the actuators is derived by the influence matrix method. It can be used to determine the adjustment amount of actuators to reduce the rms of the optical path difference. And, the least squares method is employed to resolve the matrix equation. The example of a 110 m aperture dual-reflector antenna is carried out by finite element analysis and the proposed method. The results show that the optical path difference is reduced significantly at various elevation cases, which indicates that the proposed method is effective.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Sun, ZX [Sun, Zixu][ 1 ]
Wang, XH [Wang, Xinghui][ 1 ]
Cai, TW [Cai, Tingwei][ 1 ]
Meng, Z [Meng, Zhen][ 1 ]
Han, WQ [Han, Wei-Qiang][ 1,2 ]
摘要： A composite with ultrafine SiOx (x 1⁄4 1.57, around 2 nm) nanoparticles confined in a carbon framework is synthesized by a simple thermopolymerization process and subsequent heat treatment. In the composite, the carbon framework can provide a consecutive network to improve the electrical conductivity of the composite and cushion the volume expansion to prevent the active material peeling from the current collector. The ultrafine SiOx nanoparticles can alleviate mechanical strain and shorten the diffusion/transport distance of lithium ions and electrons. In consequence, the as-synthesized composite delivers a high reversible capacity of 540 mA h g 1 at a current density of 500 mA g 1 after 200 cycles. The composite delivers good electrochemical performance, making it a promising candidate for the next-generation high-energy LIBs.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Sun, ZX [Sun, Zixu][ 1 ]
Wang, GJ [Wang, Guangjin][ 2 ]
Cai, TW [Cai, Tingwei][ 1 ]
Ying, HJ [Ying, Hangjun][ 1 ]
Han, WQ [Han, Wei-Qiang][ 1,3 ]
摘要： In this work, we synthesize a sandwich-structured graphite-metallic silicon@C (MS-G@C) composite, which shows good electrochemical performance compared to metallic silicon or graphite-metallic silicon. The improved electrochemical performance may be ascribed to the sandwich structure of the composite with the carbon coating on metallic Si and to the metallic Si particles with high electronic conductivity according to the results of four probe tester measurement and a density functional theory study. When evaluated as an anode material for LIBs, the low cost MS-G@C anodes Exhibit 830 mA h g 1 at 0.5 C, 650 mA h g 1 at 1 C, and 251.2 mA h g 1 at 5 C, respectively, and after 100 cycles with an average capacity loss of only 0.02% per cycle at 0.5 C. The synthetic method presented in this paper is provided a facile and low-cost strategy for the large-scale production of silicon-based material as an anode in LIBs.
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