JIANG Li-hong
,
WANG Ai-guo
,
TIAN Nai-yuan
,
ZHANG Wei-cun4
,
FAN Qiao-li4
钢铁研究学报(英文版)
The continuous casting technological parameters have a great influence on the secondary dendrite arm spacing of the slab, which determines the segregation behavior of materials. Therefore, the identification of technological parameters of continuous casting process directly impacts the property of slab. The relationships between continuous casting technological parameters and cooling rate of slab for spring steel were built using BP neural network model, based on which, the relevant secondary dendrite arm spacing was calculated. The simulation calculation was also carried out using the industrial data. The simulation results show that compared with that of the traditional method, the absolute error of calculation result obtained with BP neural network model reduced from 0.015 to 0.0005, and the relative error reduced from 6.76% to 0.22%. BP neural network model had a more precise accuracy in the optimization of continuous casting technological parameters.
关键词:
continuous casting
,
technological parameter
,
secondary dendrite arm spacing
,
BP neural network
Superconductor Science & Technology
In this paper we report the transport properties of c-axis-oriented superconducting La(1.44)Nd(0.4)Sr(0.16)CuO(4) films on LaSrAlO(4) substrates with different thicknesses in various magnetic fields parallel and perpendicular to the c axis of the films. It is found that with decreasing film thickness there is a crossover from the parallel shift to fan-shape broadening in the resistive transitions. Moreover, for both field configurations, the flux pinning potential U(0)(H) of the film shifts upward with an order of magnitude with increasing in-plane compressive strain. These results indicate that the compressive epitaxial strain and strain-induced destabilization of the static charge stripes are important aspects for the promotion of superconducting transition temperature as well as the flux pinning potential.
关键词:
high-temperature superconductors;crystal thin-films;flux motion;la2-xsrxcuo4;strain;insulator;dependence;behavior
徐徽
,
刘卫平
,
苏元智
,
石西昌
,
杨喜云
材料导报
采用机械球磨结合微波法合成了Cr3+掺杂锂离子电池正极材料Li1-xCrx FePO4.通过X射线衍射(XRD)、扫描电镜(SEM)和恒电流充放电测试研究了Cr3+掺杂方式和掺杂量对样品的物相结构、形貌和电化学性能的影响.实验结果表明,微波法可以快速合成Li1-xCrx FePO4正极材料；以共沉淀掺杂方式合成的样品Li0.99 Cr0.01FePO4具有最好的电化学性能,在室温下以20mA/g进行充放电测试,其首次放电容量为153.59mAh/g,10次循环之后还有149.29mAh/g,容量保持率为97.20%.
关键词:
LiFePO4
,
正极材料
,
Cr3+掺杂
,
微波
,
锂离子电池
祝宝军1
,
陶颖2
,
张旸1
,
郑锐1
,
邹小林1
无机材料学报
doi:10.3724/SP.J.1077.2010.00631
采用溶剂热电化学法, 于SiO2、V2O5、LiOH的乙醇溶液组成的反应体系中, 在Pt基体上制备出致密的Li3+xV1-xSixO4薄膜. XRD、IR、Raman分析表明, 薄膜结晶状态良好, 具有γ-Li3PO4型结构. 其化学组成为0.4 (Li4SiO4)- 0.6(Li3VO4). 薄膜中无Li2SiO3杂质相存在. 低沸点乙醇溶液体系, 能够提高反应釜内的压力, 有利于促进薄膜的生成. 组成元素在醇溶液体系离子浓度小, 薄膜生成速度小, 导致薄膜结构致密, 表面光滑.
关键词:
溶剂热电化学法
,
solid electrolyte
,
film
,
thermodynamics analysis
Physical Review B
We present a systematic first-principles investigation of the high-pressure structural stability of Li(2)BeH(4). Our total-energy calculations show that at ambient pressure, the structure of alpha-Li(2)BeH(4) observed in experiments is more stable than the other proposed structures in this work and the structural transformation from alpha to beta (Cs(2)MgH(4) type; Pnma) occurs at 18.1 GPa, together with a volume reduction of 4.7%. A detailed study of their electronic structures under ambient pressure up to 30.0 GPa reveals that this behavior is closely related to the variation in the Be-H covalent bonding in the BeH(4) anionic subunits of Li(2)BeH(4). Based on a colligated analysis of the covalent bond number per unit area (N(a)) and the scaled bond overlap population (BOP(s)), beta-NaAlH(4) and beta-Mg(AlH(4))(2) are expected to be the most promising candidates for hydrogen storage among the other investigated materials. However, the improvement of hydrogen absorption and/or desorption for Li(2)BeH(4) is less significant.
关键词:
hydrogen-storage materials;crystal-structure;electronic-structure;hydride;libeh3;phase;tungstate;alanates;solids
