Experimental and numerical simulation of lignite chemical looping gasification with phosphogypsum as oxygen carrier in a fluidized bed

Phosphogypsum (PG) is a solid waste produced in the wet process of producing phosphoric acid.Lignite is a kind of promising chemical raw material.However,the high sulfur of lignite limits the utilization of lig-nite as a resource.Based on fluidized bed experiments,the optimal reaction conditions for the production syngas by lignite chemical looping gasification (CLG) with PG as oxygen carrier were studied.The study found that the optimal reaction temperature should not exceed 1123 K;the mole ratio of water vapor to lignite should be about 0.2;the mole ratio of PG oxygen carrier to lignite should be about 0.6.Meanwhile,commercial software Comsol was used to establish a fuel reaction kinetics model.Through computational fluid dynamics (CFD) numerical simulation,the process of reaction in fluidized bed were well captured.The model was based on a two-fluid model and coupled mass transfer,heat transfer and chemical reac-tions.This study showed that the fluidized bed presents a flow structure in which gas and solid coexist.There was a high temperature zone in the middle and lower parts of the fluidized bed.It could be seen from the results of the flow field simulated that the fluidized bed was beneficial to the progress of the gasification reaction.     

Characterization of wet microalgal cells pretreated with steam for lipid extraction

Steam pretreatment was employed to disrupt microalgal cells for lipids extraction.Effects of steam pre-treatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM) and transmission electron microscopy (TEM).Effect of treatment on lipid extraction was also stud-ied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macro-molecules contained in cell wall.Maximum curvature was increased from 1.88 × 10-6 m-1 to 1.43 × 10-7 m-1 after treatment with the steam at 130 ℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pre-treatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130 ℃ and pretreatment time of 60 min.Lipid extracted from wet microalgal was signif-icantly increased (2.1-fold) after pretreatment.     

Technology for recycling and regenerating graphite from spent lithium-ion batteries

With the annual increase in the amount of lithium-ion batteries (LIBs), the development of spent LIBs recycling technology has gradually attracted attention. Graphite is one of the most critical materials for LIBs, which is listed as a key energy source by many developed countries. However, it was neglected in spent LIBs recycling, leading to pollution of the environment and waste of resources. In this paper, the latest research progress for recycling of graphite from spent LIBs was summarized. Especially, the processes of pretreatment, graphite enrichment and purification, and materials regeneration for graphite recovery are introduced in details. Finally, the problems and opportunities of graphite recycling are raised.     

A panoramic view of Li7P3S11 solid electrolytes synthesis,structural aspects and practical challenges for all-solid-state lithium batteries

The development of an inorganic electrochemical stable solid-state electrolyte is essentially responsible for future state-of-the-art all-solid-state lithium batteries (ASSLBs). Because of their advantages in safety, working temperature, high energy density, and packaging, ASSLBs can develop an ideal energy storage system for modern electric vehicles (EVs). A solid electrolyte (SE) model must have an economical synthesis approach, exhibit electrochemical and chemical stability, high ionic conductivity, and low interfacial resistance. Owing to its highest conductivity of 17 mS·cm^-1, and deformability, the sulfide-based Li₇P₃S₁₁ solid electrolyte is a promising contender for the high-performance bulk type of ASSLBs. Herein, we present a current glimpse of the progress of synthetic procedures, structural aspects, and ionic conductivity improvement strategies. Structural elucidation and mechanistic approaches have been extensively discussed by using various characterization techniques. The chemical stability of Li₇P₃S₁₁ could be enhanced via oxide doping, and hard and soft acid/base (HSAB) concepts are also discussed. The issues to be undertaken for designing the ideal solid electrolytes, interfacial challenges, and high energy density have been discoursed. This review aims to provide a bird's eye view of the recent development of Li₇P₃S₁₁-based solid-state electrolyte applications and explore the strategies for designing new solid electrolytes with a target-oriented approach to enhance the efficiency of high energy density all-solid-state lithium batteries.     

PT二次回路多点接地引起线路过电压保护事故分析

从一起某500 kV变电站线路过电压保护装置误动事故出发,首先介绍了这次过压保护误动事故概况及事故排查过程,然后分析了过电压保护装置采集的三相电压向量,计算出电压中性点偏移电压,得出了该偏移电压造成线路B相电压过电压误动的结论,最后从原理上定性分析了PT二次回路多点接地导致保护装置误动的原因,并结合事故数据验证了理论分析的正确性.     

氟化磷酸钒钠在钠离子电池中的应用进展

钠离子电池具有安全性高、钠资源丰富、成本低等独特优势,引起了人们的广泛关注.构建具有良好电化学性能的钠离子电池的关键之一就是正极材料的选取,氟化磷酸钒钠[Na3V2(PO4)2F3]因其结构稳定性好、离子输运快、工作电位高等特点被认为是一种很有前途的正极材料.但电导率较低,使其电化学性能较差;制备成本较高,阻碍了其大规模应用的发展.综述了在提升Na3 V2(PO4)2 F3电化学性能方面的措施,主要包括改进制备方法、离子掺杂、表面包覆等.为今后高性能Na3 V2(PO4)2 F3的合理设计提供了很好的参考.     

基于随机矩阵理论的数据建模方法

随机矩阵理论作为统计学处理复杂系统和高维数据的理论工具,已越来越多地与大数据技术结合,应用于电力系统分析.首先介绍了随机矩阵的基础定义,其次介绍了随机矩阵单环定理,并依此建立了DAS量测数据的随机矩阵模型,采用平均谱半径作为其线性特征值统计量,根据平均谱半径的变化感知原始随机矩阵中数据的变化.采用IEEE 33节点配电网络作为仿真分析模型,可发现当配电网无故障稳定运行时平均谱半径随时间序列的变化情况,为后续探究配电网故障的诊断方法打下了理论基础.     

磷酸二苯酯催化的2-吲哚甲烷胺衍生物的合成

以磷酸二苯酯为催化剂,3-甲基吲哚类化合物与亚胺通过Friedel-Crafts加成反应一步合成了具有广泛药理活性的2-吲哚基甲烷胺类化合物,对反应条件进行优化。结果表明,当n(3-甲基吲哚类)∶n(亚胺)∶n(磷酸二苯酯)=1.0∶2.0∶0.1,其中,磷酸二苯酯0.0025 mmol,1 mL无水二氯甲烷作溶剂,室温下反应0.5 h时,即可得到高收率2-吲哚基甲烷胺类衍生物（85%~90%）。产物经 1HNMR、13CNMR 和 HRMS 进行了结构确定。     

X-ray Fluorescence Uptake Measurement of Functionalized Gold Nanoparticles in Tumor Cell Microsamples

Quantitative cellular in vitro nanoparticle uptake measurements are possible with a large number of different techniques, however, all have their respective restrictions. Here, we demonstrate the application of synchrotron-based X-ray fluorescence imaging (XFI) on prostate tumor cells, which have internalized differently functionalized gold nanoparticles. Total nanoparticle uptake on the order of a few hundred picograms could be conveniently observed with microsamples consisting of only a few hundreds of cells. A comparison with mass spectroscopy quantification is provided, experimental results are both supported and sensitivity limits of this XFI approach extrapolated by Monte-Carlo simulations, yielding a minimum detectable nanoparticle mass of just 5 pg. This study demonstrates the high sensitivity level of XFI, allowing non-destructive uptake measurements with very small microsamples within just seconds of irradiation time.     

Usher Syndrome in the Inner Ear: Etiologies and Advances in Gene Therapy

Hearing loss is the most common sensory disorder with ~466 million people worldwide affected, representing about 5% of the population. A substantial portion of hearing loss is genetic. Hearing loss can either be non-syndromic, if hearing loss is the only clinical manifestation, or syndromic, if the hearing loss is accompanied by a collage of other clinical manifestations. Usher syndrome is a syndromic form of genetic hearing loss that is accompanied by impaired vision associated with retinitis pigmentosa and, in many cases, vestibular dysfunction. It is the most common cause of deaf-blindness. Currently cochlear implantation or hearing aids are the only treatments for Usher-related hearing loss. However, gene therapy has shown promise in treating Usher-related retinitis pigmentosa. Here we review how the etiologies of Usher-related hearing loss make it a good candidate for gene therapy and discuss how various forms of gene therapy could be applied to Usher-related hearing loss.