Revealing the inhomogeneous surface chemistry on the spherical layered oxide polycrystalline cathode particles

The hierarchical structure of the composite cathodes brings in significant chemical complexity related to the interfaces,such as cathode electrolyte interphase.These interfaces account for only a small fraction of the volume and mass,they could,however,have profound impacts on the cell-level electrochemistry.As the investigation of these interfaces becomes a crucial topic in the battery research,there is a need to properly study the surface chemistry,particularly to eliminate the biased,incomplete characterization provided by techniques that assume the homogeneous surface chemistry.Herein,we utilize nano-resolution spatially-resolved x-ray spectroscopic tools to probe the heterogeneity of the surface chemistry on LiNi0.8Mn0.1Co0.1O2 layered cathode secondary particles.Informed by the nano-resolution mapping of the Ni valance state,which serves as a measurement of the local surface chemistry,we construct a conceptual model to elucidate the electrochemical consequence of the inhomogeneous local impedance over the particle surface.Going beyond the implication in battery science,our work highlights a balance between the high-resolution probing the local chemistry and the statistical representativeness,which is particularly vital in the study of the highly complex material systems.

Modern applications of scanning electrochemical microscopy in the analysis of electrocatalytic surface reactions

Development of reaction-tailored electrocatalysts is becoming increasingly important as energy and environment are among key issues governing our sustainable future.Electrocatalysts are inherently optimized for application towards reactions of interest in renewable energy,such as those involved in water splitting and artificial photosynthesis,owing to its energy efficiency,simple fabrication,and ease of operation.In this view,it is important to secure logical design principles for the synthesis of electrocatalysts for various reactions of interest,and also understand their catalytic mechanisms in the respective reactions for improvements in further iterations.In this review,we introduce several key methods of scanning electrochemical microscopy(SECM)in its applications towards electrocatalysis.A brief history and a handful of seminal works in the SECM field is introduced in advancing the synthetic designs of electrocatalysts and elucidation of the operating mechanism.New developments in nano-sizing of the electrodes in attempts for improved spatial resolution of SECM is also introduced,and the application of nanoelectrodes towards the investigation of formerly inaccessible single catalytic entities is shared.

EMISSION AND SURFACE CHARACTERISTICS OF A DISPENSER CATHODE COATED WITH RHENIUM

The emission and surface characteristics of a dispenser cathode coated with Re arestudied.It is found that the dispenser cathode coated with Re has both higher current densityand more uniform distribution of emission than the S-type cathode.The Auger images of Bashow that the Ba distribution on the surface of the cathode coated with Re is more uniform thanthat on the surface of the S-type cathode.The analytical results by XPS and low energy AESshow that the Ba on the surface of the cathode coated with Re has stronger metallic propertythan that on the surface of the S type cathode.

Measurement of cathode surface temperature using the method of CCD imaging in arc discharge

A two-wavelength pyrometry device using ordinary array CCD (charge coupled device) to collect the ra- diation data in the horizontal and vertical directions has been developed for measuring the cathode surface temperature during the arc discharge. Analyses of experimental results show that the device can make the measurement of the cathode surface temperature feasible. The cathode surface temperatures measured are lower than the melting point of tungsten (3653 K), and the arc current, cathode diameter, and the cathode length are the main influencing factors of the cathode surface temperature.

Data Analytical Techniques for Surface Texture Characterization of Knitted Fabrics Based on Laser Triangulation Scanner

The paper presents a study of surface texture character-ization of knitted fabrics during simulated wear based onlaser-scanned profiles.The three-dimensional profilewas obtained by scanning the fabric surface using the la-ser trlangulation technique.The analytical techniquesused to derive quantitative parameters Included statisticalanalysis,fractal analysis,and Fourler analysis.

Advances in surface plasmon resonance for analyzing active components in traditional Chinese medicine

The surface plasmon resonance(SPR)biosensor technology is a novel optical analysis method for studying intermolecular interactions.Owing to in-depth research on traditional Chinese medicine(TCM)in recent years,comprehensive and specific identification of components and target interactions has become key yet difficult tasks.SPR has gradually been used to analyze the active components of TCM owing to its high sensitivity,strong exclusivity,large flux,and real-time monitoring capabilities.This review sought to briefly introduce the active components of TCM and the principle of SPR,and provide historical and new insights into the application of SPR in the analysis of the active components of TCM.

Coal Chemistry and Morphology of Thar Reserves,Pakistan

The surface of Thar coal has been characterized by spectroscopic, microscopic and chemical methods using atomic absorption spectroscopy, fourier transform infrared analysis, X-ray diffraction, scanned electron microscopy and pH titration. The samples contained high moisture, low volatile and low to moderate sulfur content and ranked as lignite (heating value 2541 - 4289 btu/lb on moist, mineral-matter-free basis). Scanned electron micrographs show porous matrix with calcium, potassium or sodium minerals. Fourier transform infrared analysis confirmed the presence of aluminum, silica and hydrate mineral constituents also. The spectra showed C=C aromatic groups at 1604 - 1609 cm-1. Phenolic ester and carboxylic acid are identified by C=O stretching vibration peaks at 1702 cm-1. The peaks of quartz and kaolinite were observed at 900 - 1100 cm-1. Point of zero charge of Thar coal has been estimated as 6.00 to 6.27 through adsorption of H+ and OH- ions by suspending coal particles in aqueous electrolyte solution. Oxygen containing functional groups, mineral matter, and metal oxides are found to have a remarkable impact on point of zero charge. The surface characterization study will be helpful in the separation of hydrophilic impurities during coal preparation processes considering pzc as the controlling

比表面及孔径分析实验中培养学生利用物理化学知识分析问题的能力

物理化学是化学与化工等专业必修的专业基础课程,然而该课程具有理论内容多、概念抽象难懂、公式复杂易混等特点,因此学生学习起来非常困难。比表面及孔径分析仪是应用极其广泛的现代分析仪器,其使用过程中包含大量物理化学基础知识。因此借助比表面及孔径分析实验,引导学生利用开尔文公式、自由度、理想气体状态方程等物理化学知识解释仪器的工作原理,从而达到提高学生利用物理化学知识分析实际问题的能力。

分子动力学模拟在物理化学教学中的应用:固体表面润湿性

固体表面润湿性是物理化学课程界面化学部分重要的教学内容。结合分子动力学模拟方法,设计不同亲/疏水性的液滴与羟基化二氧化硅表面吸附模型,通过分析铺展过程中的接触角、界面能及径向分布函数,并利用VMD软件将铺展过程可视化呈现,帮助学生多角度理解固液界面的润湿性能。将理论与计算化学方法融入教学设计,不仅开阔学生科研视野,培养学生科学思维,还可以帮助学生深入理解理论知识,提升解决实际问题的综合能力。

吲哚及其衍生物缓蚀机理计算及性能研究

为研究开发新型的有机缓蚀剂,使用量子化学计算的方法对3种吲哚及其脂类衍生物(吲哚、吲哚乙酸甲酯、吲哚乙酸乙酯)优化后的分子结构、电荷分布和轨道能量等特征参数进行分析计算,分析总结了Fe原子与三种不同吲哚及其脂类衍生物分子间作用力的变化规律;进一步采用表面分析方法评价三种缓蚀剂具有的缓蚀性能。实验表明,吲哚的缓蚀效果最好,其次是吲哚乙酸乙酯,吲哚乙酸甲酯的缓蚀效果在三种物质中最弱,通过理论计算与实验相结合的方式,在降低繁杂基础工作量的同时,也为将来吲哚类缓蚀剂的开发提供了数据支撑。

基于DeeplabV3+网络和注意力机制的矿区地表隐患识别——以塔山煤矿30507工作面为例

为解决矿区地表隐患监测问题,以塔山煤矿30507工作面为背景,提出一种快速监测和识别矿区地表隐患的方法。利用无人机搭载传感器和倾斜摄影测量技术,构建矿区地表三维实景模型,生成正射影像和空间点云。提出基于DeeplabV3+网络和注意力机制的裂隙识别方法,改进效果优于当前主流网络。提出基于三维空间点云的沉陷分析法,用密度噪声空间聚类算法去噪,通过基于KD Tree的K近邻算法和基于Delaunay三角网的点云表面重建技术进行沉陷分析,实现矿区地表数据监测。

Si_3N_4粉体表面化学分析及表面改性

Si3N4 陶瓷是一种重要的结构陶瓷 ,本文着重阐述了Si3N4 粉体的表面分析方法 ,以及为了提高固相体积分数而进行的Si3N4

碳酸盐岩红土中氧化铁矿物表面化学特征及其吸附机理研究

应用ＸＰＳ技术，首次较系统地研究了碳酸盐岩红土中氧化铁矿物表面化学特征及其吸附机理．氧化铁矿物表面的ＸＰＳ分析表明，矿物表面和整体之间在化学成分、状态和结构等方面存在明显差异，矿物表面的这种非均匀性特征是其表面化学反应的重要动力学起因．针铁矿和赤铁矿表面对氟、砷等元素的选择性吸附及其解吸作用是造成红土中氟。

对称弧形齿线圆柱齿轮的真实齿面接触分析研究

针对传统的齿面接触分析(TCA)方法在分析宽度较大的重载齿轮时误差较大的缺点,提出了一种基于全齿面整个啮合过程的真实齿面接触分析新方法.通过建立检验真实齿面的干涉判据,利用一系列连续变化的柱面去截取啮合齿面,得到一族瞬时接触线,从而可对整个啮合过程的齿面接触情况进行分析.用此法对弧形齿线圆柱齿轮进行了实例分析,分析结果表明此方法是正确可行的.与传统的TCA方法相比,该方法不仅能更确切地反映真实齿面的实际接触斑点,还能直观地判断是否发生齿面干涉.

多孔硅的干燥方法

研究了多孔硅的阴极还原表面处理技术 ,通过该技术获得了表面平滑度良好、稳定度高、抗压强度高和耐高温性能好且在空气中可以长期干燥保存的多孔硅样品 .在其表面上可以进行光刻、镀金等工艺 ,因此 。

肌肉疲劳的sEMG时频分析技术及其在工效学中的应用

表面肌电技术作为一种无损伤的实时测量方法 ,能够客观地反映肌肉活动水平和功能状态。本文主要对工效学中有关肌肉疲劳的sEMG现场评价技术发展过程中几种主要时频技术 ,尤其是幅频联合分析 ( jointanalysisofEMGspectrumandamplitude,JASA)技术做了简要介绍和初步分析与评价。同时也对sEMG的信号分析方法。

多孔硅新的表面处理技术

对多孔硅施加阳极氧化表面处理技术 ,可有效解决多孔硅干燥时出现龟裂及坍塌 ,破坏原有多孔硅的形貌和本质的问题 .阳极氧化表面处理技术就是使用少量的负离子作用于多孔硅表面 ,满足SI分子化合价的需要 ,消除悬空键 ,促使多孔硅表面性能稳定 ,避免结构重组产生分子间的不均匀内应力 ,从而获得性能稳定、可靠、在空气中可以长期干燥保存的多孔硅 .

响应面分析法对甘蔗渣中木聚糖提取条件的优化

以甘蔗渣为原料,通过单因素实验选取因素和水平,在此基础上,综合考虑各因素对木聚糖提取率的影响,根据Box-Benhnken实验设计原理,用Design-Expert软件进行响应面分析(RSA),得出甘蔗渣木聚糖的最佳提取工艺条件:室温条件下,抽提时间3 h,固液比1:30,NaOH浓度8.56%。经验证,实际测得的木聚糖提取率为28.84%,比单因素实验的最高提取率25.57%高出3.27%,在误差允许的范围内,与模型的预测值28.17%基本相符。

纤维的表面性能及表面分析技术

阐述了纤维表面性能的重要性,并主要介绍了扫描电镜(SEM)、透射电镜(TEM)、原子力显微镜(AFM)、激光共聚焦扫描显微镜(CLSM)、X射线光电子能谱(XPS)、二次离子质谱(SIMS)等现代表面分析技术及其在制浆造纸研究中的应用。

响应面法优化超声辅助乙醇提取五味子木脂素工艺研究

目的优化五味子木脂素超声辅助提取工艺,获取工艺参数。方法利用响应面法(RSM)对五味子木脂素超声辅助乙醇提取工艺进行优化。在单因素实验基础上,选择乙醇浓度、超声提取时间和液固比为自变量,木脂素提取率为响应值,根据中心组合设计原理采用3因素5水平的响应面分析法,研究乙醇浓度、超声时间、液固比及其交互作用对五味子3种主要木脂素提取率的影响。应用SAS软件和响应面分析相结合的方法,模拟得到回归方程的预测模型和可信度,并通过岭脊分析得到最佳的提取条件。结果五味子木脂素超声辅助乙醇提取最佳条件为:乙醇浓度85%、超声时间34 min、液固比146 mL/g。该条件下3种主要木脂素类成分总提取率为1.13%。结论研究建立的模型适合五味子木脂素的提取,可用于实际生产。