Li-ion-conductive Li2TiO3-coated Li[Li0.2Mn0.51Ni0.19Co0.1]O2 for high-performance cathode material in lithium-ion battery

Journal of Solid State Electrochemistry - Li2TiO3 is used as a novel coating material to modify Li(Li0.2Mn0.51Ni0.19Co0.1)O2 electrode to enhance the electrochemical performance of the host...     

Signal modeling using the gradient search

This letter presents a new method for continuous signal modeling. Firstly, the continuous signal can be represented as a function of the trigonometric functional extension (Fourier series). Fourier series of the signal are parameterized by the fundamental frequency and unknown parameters. Then, the gradient-based iterative identification algorithm is derived, for estimating parameters of the signal model with known and unknown frequencies, separately. Finally, the simulation results indicate that the proposed algorithm is effective.     

Co-precipitation synthesis of precursor with lactic acid acting as chelating agent and the electrochemical properties of LiNi0.5Co0.2Mn0.3O2 cathode materials for lithium-ion battery

Journal of Solid State Electrochemistry - Hydroxide precursor Ni0.5Co0.2Mn0.3(OH)2 was successfully prepared by co-precipitation using lactic acid as the environment-friendly chelating agent. And...     

Numerical investigation on dynamic characteristics of drilling shaft in deep hole drilling influenced by minimal quantity lubrication

The dynamic characteristics of drilling shaft in deep hole drilling influenced by minimal quantity lubrication (MQL) is investigated. According to the features of the compressible fluid Reynolds equation in oil/air feature, a time-dependent mathematical model is established to describe the pressure distribution of cutting fluid with nonlinearity in MQL deep hole drilling. By introducing the differential transformation approach, the time-dependent pressure equation arising from cutting fluid is solved by the use of direct integral method. The influences of the rotational speed, the transverse displacement ratio, and radial clearance on the hydrodynamic pressure distribution of cutting fluid are obtained. The advantage of this method is to overcome much of the computational cost and has its rapid convergence rate. Furthermore, the nonlinear responses of drilling shaft influenced by MQL are analyzed, and the instability rotational speeds of drilling tool are discussed while the design parameters of drilling shaft system changing.     

Influence of Macro-pores on DNAPL Migration in Double-Porosity Soil Using Light Transmission Visualization Method

Double porosity is a substantial microstructure characteristic in a wide range of geomaterials. It is a natural phenomenon that can be found in many types of soil, and it can result from biological, chemical or mechanical damage. In this paper, the influence of macro-pores on dense non-aqueous phase liquid (DNAPL) migration in double-porosity medium was investigated using light transmission visualization technique. Three experiments were carried out in two-dimensional flow chambers filled with a double-porosity medium composed of a mixture of local sand and sintered kaolin clay spheres arranged in a periodic manner. In each experiment, a different volumetric fraction of macro-pores and micropores was used. Tetrachloroethylene (PCE) was used to simulate DNAPL, and it was dyed using Oil-Red-O for better visualization. A predetermined amount of PCE was injected into the flow chambers and this amount was re-calculated using image analysis. A very strong correlation was found between the PCE amount injected and the amount calculated from image analysis in each experiment. The experiment was repeated by filling the flow chamber with silica sand to represent single-porosity medium. The results show that the macro-pores have a considerable effect on the PCE migration in double-porosity soil as the PCE movement was the fastest in the third experiment which contained the largest macro-pores volume. The accuracy of the method was validated using statistical analysis. The results show a slight difference between the means of the three experiments, indicating that the method is viable for monitoring NAPL migration in double-porosity medium under different volumetric fractions of macro-pores and micropores.     

熔盐堆空气换热器结构完整性分析

熔盐堆作为第四代核反应堆备选堆型之一,运行温度高,对材料高温性能要求严格;熔盐堆空气换热器作为实验堆关键设备,工作温度高,启停机次数多,长期运行后,材料许用应力松弛下降,应力、应变可能超出允许限值,或发生蠕变疲劳失效。使用Workbench软件,对熔盐堆空气换热器进行力学分析,并对A级使用载荷要求进行结构完整性评定,结果表明:熔盐堆空气换热器满足力学性能要求,其中疲劳损伤占比重较大,高温蠕变损伤也较为显著。