This study used high-temperature melting experiments, optical microscopy, and scanning electron microscopy to investigate the effects of various Ce contents (0 wt.%similar to 0.0165 wt.%) on the microstructure and TiN precipitation behavior in high-titanium steel during slow cooling solidification. The findings show that the microstructure of the solidified steel in each experiment are equiaxed grains at a cooling rate of 0.17 degrees C/s. TiN mainly precipitates in the Liquid + delta two-phase region in this experimental steel. CeAlO3 and Ce2O2S precipitate before TiN, and their small lattice misfit with TiN (7.55% and 7.90%, respectively) are the primary cause of their propensity to act as the cores of TiN heterogeneous nucleation. The TiN area density in each experimental steel increases from 38.6 no./mm2 -> 61.4 no./mm2 -> 89.3 no./mm2 -> 105.8 no./mm2 when the Ce content in the steel rises from 0 wt.% -> 0.0015 wt.% -> 0.0058 wt.% -> 0.0165 wt.%.
The extinction characteristics of mixed particles, which are composed of various types of particles, appear to be more complex. To statistically analyze photon destinations and investigate the extinction characteristics of mixed particles by tracing all underlying events in detail, a Monte Carlo method-based extinction model has been developed. Meanwhile, an extinction spectrum measurement system was designed. A series of experiments for both single-type particle and mixed-particle systems were performed. Afterwards, global optimization algorithms are introduced to perform simultaneous inversion of sizes of mixed particles and mixing ratio based on the experimental spectrum. The inversion results show that the error for any single parameter is <2%. Performing a simultaneous inversion for particle sizes and mixing ratios leads to an increase in the relative error, but it does not exceed 9%. It indicates that the model could simultaneously invert the mixing ratio and handle particle systems with two different sizes.
采用1,3-二异丙氧基杯[4]冠-6(BPC6)和4-叔丁基-2-(α-甲基苄基)苯酚(t-BAMBP)组成的协萃体系,实现了弱碱条件(30mmol/LNaOH)下铯的选择性萃取分离.当BPC6和t-BAMBP浓度分别为10和200mmol/L时,协萃系数高达89.5.反萃过程仅用10mmol/LHCl或313K热水即可分别达到84.1％和81.3％的反萃率.此外,本工作提出了配位-阳离子交换的耦合协萃机理;获得了萃取反应的热力学参数和平衡常数;探究了温度对反萃过程的影响;确立了一种温和条件下萃取/反萃铯的协萃体系.
为提高回转窑内煤粉燃烧效率,实现回转窑的节能运行,建立了回转窑内煤粉燃烧数学模型.通过控制单一变量和设计多指标正交试验工况,研究了空气过剩系数、煤粉粒径、旋流角度、内外风量比4个因素对回转窑内煤粉燃烧的影响,得到了最优操作参数组合.结果表明,随着空气过剩系数和煤粉粒径增大,火焰长度增大、火焰直径减小,火焰变得细长.随着旋流角度增大,火焰形状变短变粗.随着内外风量比增大,火焰长度先增大后减少、火焰直径先减少后增大.四个因素按影响程度从高到低排序依次为煤粉粒径、内外风量比、空气过剩系数、旋流角度.回转窑内煤粉燃烧的最优操作参数组合为空气过剩系数1.1、煤粉粒径40 µm、旋流角度25°、内外风量比0.9.相较原始工况,优化工况的火焰长度和火焰直径分别增大了 8.9％和 13.9％.
采用大涡模拟研究了凹壁面切向射流作用下近壁面圆球型颗粒对流体流动特性的影响,模拟获得的尾涡结果与实验示踪剂图像吻合较好.研究了颗粒尾流的涡旋结构及其演变过程,考察了雷诺数Re=700～10000时颗粒周围速度、涡量及流线变化.结果表明,随着雷诺数增加,颗粒的影响区域涡量增强,涡量的峰值始终出现在颗粒迎流面,颗粒后侧的回流区显著收缩.Re≥2000时在射流展向颗粒后侧存在两个尾涡,流体的切向速率和涡量均发生周期性波动.对颗粒的升力和阻力进行了监控,Re=2000时旋涡脱落频率对应的斯特劳哈尔数St=0.000854,升力功率谱中峰值对应的St=0.00152;Re=10000时阻力功率谱没有发现峰值,升力功率谱中峰值对应的St=0.00874.
