Characterization of CuO Species and Thermal Solid-Solid Interaction in CuO/CeO_2-Al_2O_3 Catalyst by In-Situ XRD, Raman Spectroscopy and TPR

Transference of CuO species and thermal solid-solid interaction in CuO/CeO2-Al2O3 catalyst prepared by an impregnation method were characterized by in-situ XRD, Raman spectroscopy and H2-TPR techniques. For the catalyst calcined at 300℃, two kinds of CuO species coexist on the surface, that is, highly dispersed and bulk CuO crystalline phase. Four kinds of CuO species are present for the catalyst calcined at 600 ℃, ： （1） highly dispersed CuO, （2） bulk CuO on the surface, （3） bulk CuO in the internal layer of CeO2, and （4） CuAl2O4 formed from CuO-Al2O3 interaction. For the catalyst calcined at 800 ℃,C, besides very little highly dispersed and bulk CuO on the surface, most of the CuO has transferred into the internal layer of CeO2 and the mass of CuAl2O4 are increased. At 900 ℃,, all of CuO has diffused into the internal layer of CeO2 and formed CuAl2O4. The results show that the distribution of CuO species in the catalysts depends on the calcination temperature; the different CuO species can be effectively confirmed by in-situ XRD, Raman spectroscopy and H2-TPR techniques.

Kinetics of synthesis of Li_4Ti_5O_(12) through solid-solid reaction

Sohd-solid reaction under low heat or low temperature is an approach to synthesize various kinds of materials that were widely used in electrochemistry field. In this paper a theoretical treatment has been presented for analyzing the mechanism of sohd-solid reaction and deriving a series of formulae to describe the variation and rate of reactions. This new model has been used in the manufacturing of spinel Li4Ti5O12. The results show that this new model works very well and will play a useful role for guiding the manufacturing of electrochemical materials.

In situ characterizations of solid-solid interfaces in solid-state batteries using synchrotron X-ray techniques

The solid-solid electrode-electrolyte interface represents an important component in solid-state batteries(SSBs),as ionic diffusion,reaction,transformation,and restructuring could all take place.As these processes strongly influence the battery performance,studying the evolution of the solid-solid interfaces,particularly in situ during battery operation,can provide insights to establish the structure-property relationship for SSBs.Synchrotron X-ray techniques,owing to their unique penetration power and diverse approaches,are suitable to investigate the buried interfaces and examine structural,compositional,and morphological changes.In this review,we will discuss various surface-sensitive synchrotron-based scattering,spectroscopy,and imaging methods for the in situ characterization of solid-solid interfaces and how this information can be correlated to the electrochemical properties of SSBs.The goal is to overview the advantages and disadvantages of each technique by highlighting representative examples,so that similar strategies can be applied by battery researchers and beyond to study similar solid-solid interface systems.

Study on the Pulsed Flashover Characteristics of Solid-Solid Interface in Electrical Devices Poured by Epoxy Resin

In electrical devices poured by epoxy resin, there are a lot of interfaces between epoxy resin and other solid dielectrics, i.e. solid-solid interfaces. Experiments were carried out to study the flashover characteristics of two typical solid-solid interfaces （epoxy-ceramic and epoxy~ PMMA） under steep high-voltage impulse for different electrode systems （coaxial electrodes and finger electrodes） and different types of epoxy resin （neat epoxy resin, polyether modified epoxy resin and polyurethane modified epoxy resin）. Results showed that, the flashover of solid-solid interface is similar to the breakdown of solid dielectric, and there are unrecoverable carbonated tracks after flashover. Under the same distance of electrodes, the electric stress of coaxial electrodes is lower than that of finger electrodes; and after the flashover, there are more severe breakdown and larger enhanced surface conductivity at interface for coaxial electrodes, as compared with the case of finger electrode. The dielectric properties are also discussed.

Single Step Solid-Solid Reaction Scheme for the Synthesis of Cobalt Sulphide-Oxide Nanoparticles in Polymer Matrix

At present, there is considerable interest in polymer-metal chalcogenides/oxides based nano-composites on account of their tunable optical, magnetic, electronic and catalytic properties. Here in, we report a simple single step approach for the in-situ synthesis of combined cobalt sulphide/cobalt oxide in polyphenylenesulphide (PPS) polymer matrix. We have illustrated the suitability of this methodology by reacting commonly available cobalt precursors with engineering thermoplastic, PPS. The cobalt precursor was homogeneously mixed with PPS in the molar ratios of 1:1, 1:5, 1:10, 1:15, respectively, followed by heating the mixtures obtained at the melting temperature of the polymer (285?C) for six hours. The resultant products were characterized by X-ray Diffractometry (XRD), Field-Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscope (HRTEM), Diffuse Reflectance Spectroscopy (DRS) technique and Fourier Transformation Infra red Spectroscopy (FTIR). Formation of mixed phases viz., sulphide and oxide of cobalt within modified PPS matrix was confirmed by XRD. The resultant nanoparticles of cobalt sulphide and cobalt oxide embedded in the PPS matrix showed crooked and chunk morphology. The optical properties of the resultant nanocomposites indicate the shift in the absorption hump due to nanoscale size effect.

Effect of toughened epoxy resin on partial discharge at solid-solid interface

A series of solid-solid interfaces, consisting of ceramic-epoxy resin interface samples with a tip-plate electrode, were investigated by performing partial discharge tests and realtime electrical tree observations. A toughening agent was added to the epoxy resin at different ratios for comparison. The impact strength, differential scanning calorimetry （DSC） and dielectric properties of the cured compositions and ceramic were tested. The electric field strength at the tip was calculated based on Maxwell＇s theory. The test results show that the addition of a toughener can improve the impact strength of epoxy resin but it decreases the partial discharge inception voltage （PDIV） of the interface sample. At the same time, toughening leads to complex branches of the electrical tree. The simulation result suggests that this reduction of the PDIV cannot be explained by a change of permittivity due to the addition of a toughening agent. The microstructural change caused by toughening was considered to be the key factor for lower PDIV and complex electrical tree branches.

Dynamically self-adjustable liquid-liquid and self-adaptive softcontact solid-solid triboelectric nanogenerator for wave energy harvesting

Water wave energy exhibits great potential toalleviate the global energy crisis. However, harvesting andutilizing wave energy are challenging due to its irregularity,randomness, and low frequency. Triboelectric nanogenerators(TENGs) have gained significant attention for harvesting waveenergy with high efficiency. This study presents a novelellipsoidal, pendulum-like TENG integrating both liquid-liquid(L-L) and solid-solid (S-S) triboelectricity (LS-TENG). Thisinnovative design enables continuous wave energy harvestingand self-powered marine environment monitoring under variousconditions, including temperature, humidity, and light intensity. The binary immiscible liquids within the LS-TENG’s innersoft balloon create dynamic, and self-adjustable L-L contact interfaces, significantly increasing the L-L contact area andenhancing L-L contact electrification (CE). The unique self-adaptive, soft S-S contact increases the S-S contact areacompared to traditional hard point contact, better adapting to the irregular movements of waves and promoting efficient S-SCE. The LS-TENG achieves highly efficient wave energy harvesting by coupling L-L and S-S CE. Furthermore, the uniquesoft contact design protects the S-S interfaces from mechanical wear and damage during long-term work. The LS-TENG’snovel structure provides an innovative and effective way for water wave energy harvesting.

Advanced solid-solid phase change thermal storage material

The practicality of conventional solid-liquid phase change materials(PCMs)is adversely restricted by liquid phase leakage,large volume expansion,shape instability,and severe corrosion in high-temperature thermal management systems.This highlight presents the latest development to resolve these challenges by designing ultrahigh-performance high-temperature Ni-Mn-Ti solid-solid PCMs using martensitic phase transition strategy,offering a new paradigm to develop advanced wide-temperature high-temperature metallic solid-solid phase change thermal storage materials.

Electrospun Polyethylene Glycol/Polyvinyl Alcohol Composite Nanofibrous Membranes as Shape-Stabilized Solid-Solid Phase Change Materials

In this work,shape-stabilized solid-solid phase change materials(PCMs)were fabricated by simply electrospinning polyethylene glycol(PEG)and polyvinyl alcohol(PVA).Owing to the strong hydrogen bonds and entanglement between those molecular chains of PEG and PVA,PEG was packaged by PVA.The morphological structures,thermal stability and thermal energy storage properties of those fibers were investigated.SEM results showed that those electrospun PVA/PEG composite membranes hold a three-dimensional nonwoven web structure even the content of PEG as high as 70%.The thermal energy storage ability of those composite fibers increased with the increase of the content of PEG.The heat enthalpies of PEG/PVA=7/3 were as high as 78.806 J/g.Moreover,those composite fibers had excellent thermal stability.After 100 heating and cooling cycles,there was almost no obvious change in the melting enthalpy and crystallization enthalpy.Those fibers still maintained good thermal regulation.The simple preparation process,low cost of raw materials and excellent stability endow the PCMs great utilization potentiality in smart textile and energy storage systems.

聚氨酯型固-固相变储能材料对沥青调温效果的影响研究

聚氨酯型固-固相变储能材料可以有效提高沥青的相变储能能力,从而在调节路面温度的同时,减小温度波动。基于上述背景,针对聚氨酯型固-固相变储能材料对沥青调温效果的影响展开研究。确定相变材料的分类标准,并分别研究其储能原理及具体应用情况,完成对聚氨酯型固-固相变储能材料特性的分析。在此基础上,定义周期性储热边界条件,根据沥青调温过程中内聚能密度的变化形式,推导相变储能材料的能量变化规律,从而确定聚氨酯型固-固相变储能材料对沥青调温效果的影响能力。

非线性电导涂层对直流GIL绝缘子空间/表面电荷和沿面电场的调控研究

空间/表面电荷积聚是导致直流GIL绝缘子沿面闪络电压降低的潜在原因,涂敷非线性电导涂层是提升沿面绝缘性能的有效方法。本文建立了电场依赖性非线性电导涂层对绝缘子空间/表面电荷及沿面电场调控的数学模型,综合考虑了绝缘气体电流密度以及绝缘子固体电导率与电场强度的非线性关系,通过该模型研究了温度梯度分布下绝缘子内部电荷的分布规律,以及非线性电导涂层对绝缘子表面电荷积聚的影响机制。结果表明:非线性电导涂层对空间电荷消散有明显的促进作用,高压电极附近的同极性电荷主导了表面电荷分布;由于表面电荷分布和切向电场的改善,绝缘子的沿面闪络性能得到提高;在绝缘子与涂层界面之间会积聚正电荷,并从高压电极向地电极逐步递减。

基于CFD-DEM的流-固耦合数值建模方法研究进展

随着土体渗流侵蚀研究的逐渐深入,对土颗粒流失和变形破坏机理的研究方法呈现出多尺度的特点。其中,计算流体力学-离散元耦合方法(CFD-DEM)为在细观尺度上研究流-固耦合相互作用对土体宏观力学特性的影响提供了一种行之有效的方法。针对CFD-DEM耦合方法在岩土工程领域应用现状,本文系统总结现有流-固耦合计算方法的优缺点,重点论述CFD-DEM耦合方法的建模策略,包括固相颗粒形状建模与粒间接触模型、流体相控制方程及参数计算方法,以及CFD-DEM耦合计算,并就相关问题进行深入探讨,最后提出了CFD-DEM耦合方法未来的发展方向。

基于专利数据挖掘的固态锂电池关键材料分析

固态锂电池作为下一代高性能储能技术,其关键材料的研发对于提高固态锂电池的能量密度、稳定性和安全性至关重要。本文以全球固态锂电池专利为研究对象,基于文本挖掘方法提取和整理固态锂电池专利文献中的材料信息,通过主要材料分布和共现网络重点分析了固态锂电池的材料分布特点和潜在研发材料,通过机构-材料的分布和共现网络重点分析了主要研发机构的材料布局和研发重点,梳理了2021年以来固态锂电池专利中出现的新材料及其研发机构,揭示了固态锂电池材料领域的现有研究热点和未来发展趋势。研究结果显示,锂、铝、镧、磷、硫化物等材料在固态锂电池专利中占据重要地位;大部分机构围绕核心材料进行创新和合作,在材料开发和应用方面具有相似的策略;少数重要机构积极开发固态锂电池的新材料并广泛布局相关专利,对固态锂电池的材料开发、技术创新和商业化有推动作用。本文为固态锂电池材料的分析和挖掘提供了新的方法,为固态锂电池的材料研发和技术创新提供参考。

固体火箭发动机零维内弹道点火模型与计算

点火过程是内弹道的初始阶段,但由于点火过程的复杂性以及点火机理仍然不完善,点火过程始终不能与内弹道有机结合,使得目前工程上的内弹道计算只能忽略点火过程而直接选择点火压强作为计算初始点。以零维内弹道理论为基础,建立了点火过程3个阶段,即点火诱导期、火焰传播期和充气期的简化理论模型,可以与零维内弹道有机结合,从而完成了内弹道从环境压强(而不是点火压强)开始计算的完整过程。通过实例计算与验证,该模型能够很好展示在点火阶段燃烧室压强的建立过程,并可以计算得到点火延迟时间、火焰传播时间、点火药流量等点火参数,具有较高的预示精度,满足工程计算要求。研究表明,建立的点火过程理论模型与传统零维内弹道一样计算简便快捷,并具有较好精度的工程应用化特点。研究结果对于完善固体火箭发动机内弹道理论、提高固体火箭发动机内弹道预示精度,均具有重要的实际应用意义。由于采用了简化的点火过程理论模型,该结果不能直接用于点火性能的研究,只能用于零维内弹道性能的预估与计算。

新《固废法》对皮革行业的影响研究

固体废物(简称固废)是指生产型企业产生的固体工业垃圾。在皮革企业生产过程中会产生固体废物,如皮革边角料、污泥。新《固废法》对旧版固废法进行了有效的补充,提高了对固体废物、危险废物的鉴别、检测要求,健全了固体废物污染环境防治长效机制,确保以最严格的制度和法治保护生态环境。皮革行业急需提升固体废物和危险废物的管理能力,这对皮革行业提出了更高的要求。本文解读了新《固废法》内容,深入剖析皮革行业固废处理现状,介绍了皮革行业的固废来源和重点内容,有利于皮革行业重视固体废物和危险废物,将废物妥善处理,共建绿色家园。

射流与气固两相流混合过程的测试与分析方法

湍流射流是气固快速反应过程中气相原料与固体颗粒的理想混合形式,采取有效的测试技术与分析方法获得射流与气固两相流的混合行为对研究反应过程具有重要意义。本文采用光纤探针技术获得了颗粒浓度动态数据,以提升管内颗粒聚团的传统分析方法为基础,结合小波分析,提出了射流与气固两相流混合过程中颗粒聚团的确定方法,并将射流影响区内气固间的瞬时接触状态分为颗粒聚团相、散式颗粒相以及未与颗粒充分混合的射流相。结合附壁射流理论,利用气体示踪技术获得的射流特征浓度分布结果,对理想条件下的射流中心线方程进行了修正,所得结果可预测气固两相流中射流的发展趋势。利用臭氧分解示踪技术,获得了原料射流与气固两相流混合过程中的局部反应结果,将其与气固动态混合特征及射流轨迹模型相结合,可分析流动参数对反应的影响。

使固态化学反应100%完成的方法

无溶液形成的固态化学反应具有“一旦发生,就必完全”的特质,但因为固体的非流动性,它常常会因严重的传质困难而有始无终。为了克服这个困难,作者提出了少溶剂固态化学反应(LSR)的概念,即通过使用少量的溶剂赋予固体流动性,使反应物固体部分溶解,再使用搅拌反应器解决其“三传”问题,使之完全反应,从而达到使一些化学工业过程绿色化的目的。本文用平衡热力学数值计算的方法图解了几种代表性LSR的Gibbs自由能随反应进度的关系,进而指出:LSR的中间阶段如同没有溶液形成的固态化学反应,两端像溶液化学反应,因此,LSR虽继承了混合自由能导致的化学平衡,但其平衡点比溶液化学反应更接近100%完全。特别地,在LSR即将结束时,通过逐步移除溶剂以使反应物和产物固体持续存在而延长中段,能推动反应达到100%完全;对于连串反应,LSR仍有可能通过控制反应物的物质的量之比来获得中间产物;对于Δ_rG_m~?略小于零的反应,可以通过使用较多的溶剂跨越可能的早期平衡态,或者使用大量的产物固体“种子”使所有的产物一直与其饱和溶液平衡,最终通过逐渐蒸发溶剂推动反应进行到底;LSR的反应速度与反应物或产物的溶解度关系不大,但与反应物的溶解速度、化学反应速度和产物的结晶速度紧密相关。本文还讨论了使一些竞争反应、非自发反应进行到底的方法,获得高度的反应控制能力。

不同固-固掺杂工艺对氧化锆弥散强化钼合金性能的影响

以氧化锆作为添加剂,采用粉末冶金法分别在二氧化钼和钼粉中固-固掺杂制备出了氧化锆弥散强化钼合金。分析对比了合金金相组织及微观结构的差异,并测试了不同掺杂工艺制备出的钼锆合金的抗拉强度、硬度以及再结晶温度。试验表明:采用不同的固-固掺杂工艺制备出的钼锆合金在力学性能、加工性能以及再结晶温度方面存在一定差异。在二氧化钼中掺杂氧化锆制备的钼锆合金经过一定程度塑性加工之后硬度、抗拉强度更高,加工硬化现象更明显,加工至∅0.68 mm丝材的再结晶温度约为1400℃,比相同条件下在钼粉中添加氧化锆制备的钼锆合金再结晶温度提高约200℃左右,具备更好的高温力学性能。

固体火箭冲压发动机气固两相掺混燃烧过程评价方法

为了合理地评价固体火箭冲压发动机补燃室内一次燃气/空气掺混燃烧过程,提出一种基于颗粒质量浓度的固体火箭冲压发动机掺混燃烧过程评价方法。建立发动机数值模拟方法并通过了地面试验验证;针对不同工况条件下补燃室掺混燃烧过程,通过数值模拟,分析对比了不同定义方式掺混度与燃烧效率的变化趋势。结果表明,提出的颗粒掺混度与颗粒燃烧效率二者间显示出最大程度的相关性,不同工况下的平均最大信息系数达到了0.9163。一次燃气/空气掺混与燃烧过程体现以下相关性规律:颗粒燃烧效率随颗粒掺混度的增大而增加,当颗粒掺混度超过一定阈值后,颗粒燃烧效率保持相对稳定。最后通过试验验证了该规律。

“无废城市”背景下《固体废弃物处理》课程教学改革——以含铊固废资源化为例

2018年我国提出了“无废城市”理念,而固体废弃物资源化是实现“无废城市”目标的关键途径之一。本文阐述了“无废城市”,明确指出固体废弃物的“减量化”、“资源化”、“无害化”原则均体现了“无废城市”理念,且资源化以无害化为前提,这是《固体废弃物处理》课程教学大纲修订的要求。另外,随着新能源电池的发展,锂行业发展迅猛,导致与锂行业有关的含铊固废堆积如山,目前含铊固废的有效处理处置将是整个锂行业的关键瓶颈。本文以含铊固废为例,从稀散金属铊的特性、含铊固废的来源、含铊固废中铊的富集方法(包括火法/湿法富集铊、烟尘中富集铊精矿、离子交换法富集铊)、富集铊后的固废建材化等方面阐述含铊固废资源化利用。探讨《固体废弃物处理》课程教学大纲和教学内容的修订和改革,为我国“无废城市”目标的达成和生态文明建设提供人才保障。