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应用商业软件ANSYS CFX计算了等离子体热通量和液态锂流速对自由流动液态锂温度分布的影响。计算结果表明,导向槽中心附近液态锂温度较高,冷却水入口和出口对应位置液态锂温度最低。液态锂出口温度随着等离子体热通量的增大而线性升高,冷却水流速为1.5m·s-1,热通量分别为0.1MW·m-2和1MW·m-2时,液态锂在出口处对应的温度分别为255.3°C和458.6°C。增大液态锂流速,导向槽内液态锂的温度逐渐降低,但温度变化的幅度较小。计算结果对液态锂回路安全稳定运行提供了一定参考。     

热通量和液态锂流速对自由流动液态锂温度分布的影响

应用商业软件ANSYS CFX 计算了等离子体热通量和液态锂流速对自由流动液态锂温度分布的影响。计算结果表明,导向槽中心附近液态锂温度较高,冷却水入口和出口对应位置液态锂温度最低。液态锂出口温度随着等离子体热通量的增大而线性升高,冷却水流速为1.5m·s⁻¹,热通量分别为0.1MW·m⁻² 和1MW·m⁻² 时,液态锂在出口处对应的温度分别为255.3°C 和458.6°C。增大液态锂流速,导向槽内液态锂的温度逐渐降低,但温度变化的幅度较小。计算结果对液态锂回路安全稳定运行提供了一定参考。     

Elastic constants of lithium thallium tartrate measured by Brillouin scattering

All components of the elastic stiffness tensor of lithium thallium tartrate at room temperature have been measured by Brillouin scattering techniques using two different scattering configurations. Refractive indices have been determined independently by optical measurement. The results are compared with previous work on lithium thallium tartrate and lithium ammonium tartrate.     

Interaction of nitrogen with lithium in lithium ion batteries

The reaction of N₂ with lithium at electrode in lithium ion batteries was reported in this paper. At room temperature, N₂ can react with lithium, mainly at anode, to form Li₃N in an electrochemical system very easily during charge–discharge cycles. Li₃N has been characterized by XPS. Experimental results also revealed that the higher of the current density and higher of the temperature resulted in quicker of the nitrogen-fixation reaction. Moreover, the reaction of nitrogen with Li was faster at the TiO₂-coated cathode than at the uncoated cathode. The reaction can be brought about almost completely in the lithium ion batteries at room temperature. This could be a new method for preparation of Li₃N at room temperature.     

液态锂限制器的铺展性测试平台设计及初步实验

为研究液态锂在电磁驱动限制器表面的铺展特性,设计了与EAST限制器接口相同的限制器测试平台.该平台运行时真空环境可达10?4Pa,对被测限制器可加热至350℃.在限制器锂回路管道上,利用外部2T水平磁场以及竖直方向施加的最大为200A的直流电流,形成电磁驱动力驱动下的锂液循环回路.测试平台设有顶部和正面两个观察窗,能够...     

Pressure effects on the kinetic properties and phase transitions in lithium

The pressure dependences of the electrical resistance and thermal electromotive force of lithium were measured at room temperature. The results substantiated the occurrence of a phase transition caused by increasing pressure (6.7 GPa). A phase transition was detected when pressure was decreased (6.4 GPa). Temperature effects on the pressures of these transitions were studied near room temperature. At pressures above 4 GPa, the pressure dependences of thermal electromotive force and of the velocity of ultrasonic shear waves in BCC lithium exhibited anomalies. The suggestion was made that applying pressure increased the role played by electron-phonon and phonon-phonon interactions in lithium.     

Design of thermally stable ferrite materials for the decimeter range

The discussion concerns the parameters needed for antennas containing ferrites. Test results are given on the saturation magnetization as a function of temperature for lithium ferrite-aluminates. Some of these with low saturation magnetization are found to show zero temperature coefficient over a wide temperature range.Read at the Third All-Union Conference on Ferrites, Leningrad, 22 October 1963.     

The ionic conductivity of rapidly quenched tungstate and molybdate glasses containing lithium halides

Rapidly quenched lithium tungstate and molybdate glasses containing up to 20 mole% lithium chloride and bromide additives have been prepared. The additives are found to give a small increase (up to a factor of two at room temperature) in the lithium ion conductivity of the glass which can be understood in terms of models developed for network forming glasses.     

锂离子电池硅基负极材料嵌锂行为的第一性原理研究

采用基于密度泛函理论的第一性原理平面波赝势方法,计算不同数量的锂离子引起的硅材料晶体结构的变化以及在嵌锂过程中形成Li_xSi(x=1、2、2.4、4.4)合金相的形成能与电子结构.采用LST/QST方法计算过渡态,模拟合金体相中的锂离子迁移过程.计算结果表明,随着嵌锂数量的增加,硅晶胞的体积在不断增大;Li_xSi合金相的形成能为负值,表明在嵌锂过程中锂离子和硅原子可以自发形成这些合金相,其中Li₇Si₃合金最容易形成;随着嵌锂量的增加,锂离子在费米能级处s轨道提供的电子数逐渐增加,锂硅合金在费米能级处的电子数量呈增大趋势,表明锂硅合金的导电性越来越优;常温下Li₂Si体相中很难直接形成锂离子空位,但锂离子空位的迁移过程很容易发生.     

Investigation of Lin, H-Lin and O-Lin interactions in fcc(100) and fcc(110) surface symmetries by molecular dynamic simulation method

We have investigated the structure and energies of lithium microclusters containing 3-10 atoms in the fcc(100) and fcc(110) surface symmetries, and the interaction of an oxygen and hydrogen atom with these lithium microclusters for the on-top, open and bridge sites approaches. The calculations have been performed with molecular dynamics simulation methods (MDSM) at 1 K temperature and the results were compared with the literature.     

Optical absorption of lithium metal vapor at high temperatures

Experimental results are reported for a unique spectroscopic device called the Plasma Spectroscopy Cell. Optical absorption of lithium metal vapor was observed at high density and temperature. Absorption spectra are analyzed using theoretical calculations of absorption cross sections for lithium-helium interactions, and singlet and triplet state transitions of diatomic lithium in the visible spectral range. This is believed to be the most complex example yet calculated in which absolute bound-bound, bound-free, free-bound, and free-free contributions for all possible optically allowed transitions are all included, in quite respectable agreement with experiment.     

Mössbauer characterization of LixFe3O4

Mössbauer spectra of lithium intercalated Fe₃O₄, have been recorded at 300 K and 4.2 K. It has been observed that lithium can be incorporated and/or extruded at room temperature. The coexistence of lithiated and unlithiated particles after exposure of the sample to air, is interpreted in terms of the Li⁺-ion mobility. The results are compared with those obtained from X-Ray diffraction data and magnetization measurements.     

New nanocrystalline manganese oxides as cathode materials for lithium batteries: Electron microscopy,electrochemical and X-ray absorption studies

New nanostructured manganese oxy-iodides were prepared by redox reaction of sodium permanganate with lithium iodide in aqueous medium at room temperature. Transmission electron microscopy (TEM) showed that they are nanocrystalline with grain size in the 5–10 nm range. TEM and X-ray absorption confirmed the short-range ordered structure of these compounds, which contain octahedrally coordinated manganese atoms. The electrochemical properties were studied as a function of preparation conditions (Li/Mn ratio, carbon incorporation at the synthesis stage and grinding). Best electrochemical results were obtained either on samples with carbon black incorporated directly in the aqueous reaction medium at the synthesis stage, or on samples with carbon mixed after synthesis, submitted to extensive grinding. Typical capacities in the potential window 1.8–3.8 V are 160 and 130 mAh/g at the 40th and 100th cycle, respectively. Step-potential electrochemical spectroscopy and the evolution of X-ray absorption spectra on discharge are consistent with a single-phase lithium intercalation reaction with simultaneous manganese oxidation–reduction.     

Raman and Hyper-Rayleigh Scattering in Lithium Tetraborate Crystals

Experimental studies of Raman scattering and the infrared reflection spectra of lithium tetraborate crystals were carried out within a broad temperature range with various polarization geometries. The crystals studied are characterized by record values of radiation resistance, transparence within a broad spectral range including the ultraviolet region, and nonlinear optical properties. A group-theoretical analysis of the vibrational spectra of this crystal was performed and fundamental vibrational terms were assigned to the symmetry types of the point group as well as the polarizations of the corresponding modes. The effective Raman cross section was measured and was found to be one order of magnitude higher than those of the known crystals, in which the stimulated Raman scattering (SRS) was observed. The nonlinear optical and electrooptical coefficients were evaluated and were found to be consistent with the results of independent measurements. The effect of a drastic increase in the intensity of quasi-elastic light scattering at 253 K was registered. It was associated with the phase transition that consists of the disordering of lithium ions with respect to the rigid skeleton. The formation energy for Frenkel defects in the lithium sublattice and the activation energy of the ionic conduction when heating the sample were calculated from the obtained temperature dependences of the intensity of quasielastic and hyper-Rayleigh light scattering.     

Auger spectra of lithium hydride

Auger electron emission spectra have been observed for lithium hydride in three conditions : (1) cleaved in vacuum, (2) prepared by the reaction of hydrogen gas with clean lithium metal, and (3) by annealing slightly oxidized lithium hydride single crystals in vacuum. The dominant Auger line (40 ± 1 eV) was found to be a KVV transition involving valence electrons from the anion and was indistinguishable from a similar transition for lithium oxide at room temperature. Lithium hydride surfaces lose hydrogen in vacuum causing the formation of a lithium metal phase at room temperature and a significant reduction in surface hydride stoichiometry at 600°C.     

自由液态锡表面结构的流体模型

应用SolidWorks 和ANSYS 软件设计了自由液态锡表面流体结构模型,计算了初始流速和热通量不同时液态锡的速度变化和温度变化,得到了流动液态锡的速度分布和温度分布。结果表明,垂直流动方向液态锡流速较为均匀,沿流动方向液态锡流速逐渐增大、液态锡液面厚度逐渐变薄。初始温度为600K 的条件下,热通量为1MW·m⁻² 时,液态锡出口温度为623.38K;热通量为5MW·m⁻² 时,液态锡出口温度为720.18K。在相同条件下使用液态锂作为计算流体,结果表明出口处液态锂的温度低于液态锡的温度。     

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应用SolidWorks和ANSYS软件设计了自由液态锡表面流体结构模型,计算了初始流速和热通量不同时液态锡的速度变化和温度变化,得到了流动液态锡的速度分布和温度分布。结果表明,垂直流动方向液态锡流速较为均匀,沿流动方向液态锡流速逐渐增大、液态锡液面厚度逐渐变薄。初始温度为600K的条件下,热通量为1MW·m?2时,液态锡出口温度为623.38K;热通量为5MW·m?2时,液态锡出口温度为720.18K。在相同条件下使用液态锂作为计算流体,结果表明出口处液态锂的温度低于液态锡的温度。     

First order phase transition of Li3 ThF7 at 281 K: A comparative study between EPR and Raman scattering

Abstract

Electron Paramagnetic Resonance (EPR) and Raman Spectroscopy were used to study the low temperature phase transition of pulled Li₃ThF₇ single crystals, occurring at 281 K. In both cases, the room temperature spectra were very broad, owing to the statistical disorder and high ionic mobility of the lithium ions, which occupy only 3/4 of their structural sites. The results are compatible with a first order ferroelastic transition from the room temperature orthorhombic D_2h ²² phase to a monoclinic C_2h ^(x) one. The symmetry rules are well respected assuming a model with four lithium ions in average per chemical formula. The EPR spectra show also the appearing of additional ferroelastic domains.     

Liquid-phase synthesis of Li2S and Li3PS4 with lithium-based organic solutions

Sulfide solid electrolytes are widely regarded as one of the most promising technical routes to realize all-solid-state batteries (ASSBs) due to their high ionic conductivity and favorable deformability. However, the relatively high price of the crucial starting material, Li₂S, results in high costs of sulfide solid electrolytes, limiting their practical application in ASSBs. To solve this problem, we develop a new synthesis route of Li₂S via liquid-phase synthesis method, employing lithium and biphenyl in 1, 2-dimethoxyethane (DME) ether solvent to form a lithium solution as the lithium precursor. Because of the comparatively strong reducibility of the lithium solution, its reaction with sulfur proceeds effectively even at room temperature. This new synthesis route of Li₂S starts with cheap precursors of lithium, sulfur, biphenyl and DME solvent, and the only remaining byproduct (DME solution of biphenyl) after the collection of Li₂S product can be recycled and reused. Besides, the reaction can proceed effectively at room temperature with mild condition, reducing energy cost to a great extent. The as-synthesized Li₂S owns uniform and extremely small particle size, proved to be feasible in synthesizing sulfide solid electrolytes (such as the solid-state synthesis of Li₆PS₅Cl). Spontaneously, this lithium solution can be directly employed in the synthesis of Li₃PS₄ solid electrolytes via liquid-phase synthesis method, in which the centrifugation and heat treatment processes of Li₂S are not necessary, providing simplified production process. The as-synthesized Li₃PS₄ exhibits typical Li⁺ conductivity of 1.85×10^-4 S·cm^-1 at 30 ℃.     

Electrical resistivity of alkali metals

The temperature variations of the electrical resistivity of alkali metals lithium, sodium, potassium, rubidium and caesium are calculated in the free electron approximation and using Krebs's model for the phonon spectrum. The double average over the Fermi surface is evaluated by an improved method due toBailyn and the separation between normal and Umklapp processes is affected in a more satisfactory manner. The results of the calculations are compared with the experimental data obtained at different temperatures. The theoretical resistivity curves for sodium, potassium, rubidium and caesium show satisfactory agreement with experiment, but not in the case of lithium.