Characterization of metallic and ceramic high-temperature materials for energy systems

For the development of metallic and ceramic high temperature materials used, for example, in heat exchanger components, in turbine blades for stationary gas turbines, in ceramic industrial products and fusion reactor components, modern physico-chemical characterization methods are required. The formation stability of naturally formed protective scales is of prime importance in the successful application of metallic materials at high temperatures in aggressive atmospheres. For the characterization and investigation of the growth mechanisms of such surface scales, the main emphasis is placed on such modern spectroscopical methods as SIMS, SNMS, GDOS, EPMA and RBS. The morphology and composition of oxide scales have been investigated by imaging and diffraction techniques. The thermal and mechanical damage behaviour of high-temperature materials for application in fusion reactor components is of importance. Damage behaviour has been simulated by electron beam and laser irradiation experiments, especially by means of in situ techniques in a scanning electron microscope. By such techniques the material erosion, crack formation and crack propagation were studied for ceramic high temperature materials as a function of load parameters. The erosion and the crack formation processes are superim-posed by a redeposition of vaporized material and by thermally activated creep of the binder phases. The application potential for all methods discussed is outlined and available results are presented.     

Capillary electrophoresis integrated immobilized enzyme reactor for kinetic and inhibition assays of β‐secretase as the Alzheimer's disease drug target

Capillary electrophoresis integrated immobilized enzyme reactors are becoming an increasingly popular alternative for enzyme kinetic and inhibition assays thanks to their unique set of features including cost effectiveness, repeated use of the enzyme, minuscule sample consumption, rapid analysis time and easy automation. In this work we present the development and application of a capillary electrophoresis integrated immobilized enzyme reactor based on magnetic particles for kinetic and inhibition studies of β‐secretase, a key enzyme in the development of Alzheimer's disease and a promising drug target. We document the optimization of the immobilization procedure, characterization of immobilized β‐secretase, optimization of a mutually compatible incubation protocol and separation method as well as the production of the capillary electrophoresis integrated immobilized enzyme reactor. The applicability of the capillary electrophoresis integrated immobilized enzyme reactor was demonstrated by kinetic assay with an unlabelled substrate and by inhibition assays using three structurally different reference inhibitors. The resulting kinetic and inhibition parameters clearly support the applicability of the herein presented method as well as document the fundamental phenomena which need to be taken in account when comparing the results to other methods.     

Conversion enhancement of tubular fixed-bed reactor for Fischer-Tropsch synthesis using static mixer

Recently,Fischer-Tropsch synthesis(FTS) has become an interesting technology because of its potential role in producing biofuels via Biomassto-Liquids(BTL) processes.In Fischer-Tropsch(FT) section,biomass-derived syngas,mainly composed of a mixture of carbon monoxide(CO) and hydrogen(H2),is converted into various forms of hydrocarbon products over a catalyst at specified temperature and pressure.Fixed-bed reactors are typically used for these processes as conventional FT reactors.The fixed-bed or packed-bed type reactor has its drawbacks,which are heat transfer limitation,i.e.a hot spot problem involved highly exothermic characteristics of FT reaction,and mass transfer limitation due to the condensation of liquid hydrocarbon products occurred on catalyst surface.This work is initiated to develop a new chemical reactor design in which a better distribution of gaseous reactants and hydrocarbon products could be achieved,and led to higher throughput and conversion.The main goal of the research is the enhancement of a fixed-bed reactor,focusing on the application of KenicsTM static mixer insertion in the tubular packed-bed reactor.Two FTS experiments were carried out using two reactors i.e.,with and without static mixer insertion within catalytic beds.The modeled syngas used was a mixed gas composed of H2/CO in 2:1 molar ratio that was fed at the rate of 30mL(STP)min1(GHSV≈136mL g1 cat h1) into the fixed Ru supported aluminum catalyst bed of weight 13.3g.The reaction was carried out at 180℃ and atmospheric pressure continuously for 36h for both experiments.Both transient and steady-state conversions(in terms of time on stream) were reported.The results revealed that the steady-state CO conversion for the case using the static mixer was approximately 3.5 times higher than that of the case without static mixer.In both cases,the values of chain growth probability of hydrocarbon products(α) for Fischer-Tropsch synthesis were 0.92 and 0.89 for the case with and without static mixer,respectively.     

Study of the Relative Sensitivity Factors (RSFs) in a Microsecond-Pulse Glow Discharge Time of Flight Mass Spectrometry

The synthesis and application of high technical materials increase the demands for the corresponding characterization techniques. Though there are several methods commercially available, a suitable technique for choice is dependent on many factors.     

A batch membrane reactor for laboratory studies

A membrane reactor consisting of two recirculating flow systems connected via a membrane module has been constructed and used to study the dehydrogenation of cyclohexane. When the reactor is operated differentially it is possible to obtain the same information that is generated when using more conventional steady flow reactors. The batch system has the advantages of easily varying the ratio of membrane area to reactor volume and sampling a very wide range of effective Damköhler numbers. These are important variables in design studies. This ability has been demonstrated for the dehydrogenation of cyclohexane. The batch system reproduced results from studies using a more conventional flow reactor. In addition, with the batch reactor it was possible to experimentally confirm predictions that were based upon computer simulation but which were outside the range of experimental study for the conventional reactors used.     

Diverse Supports for Immobilization of Catalysts in Continuous Flow Reactors

The rapid development of continuous flow processes is driving innovations in various chemical syntheses and industrial productions. Immobilizing catalysts in flow reactors allows transformations with high-efficiency and excludes the subsequent separation procedures. This concept outlines the approaches to incorporate catalysts within flow reactors, with particular focus on the application of additional supports including inorganic materials like silica, zeolite and reduced graphene oxide, polymeric materials like polymer packings, monoliths, cross-linked gels and polymer brushes, and other materials for specific conditions like transparent glass fibers and glass beads. Furthermore, advanced methods to develop ordered micro-/nanoarrays from internal walls of flow channels for immobilization of catalysts as well as application of innovative vortex fluidic devices are discussed to inspire new designs of supports for novel fluidic reactors with broad applications.     

柴油馏分加氢脱硫动力学及反应器研究进展

当前各国环保法规对柴油中硫的质量分数的限制越来越严格。催化加氢脱硫是实现柴油低硫化的重要途径,动力学和新反应器的研究受到了研究者的广泛关注。本文介绍了柴油馏分中两种典型的难脱除含硫化合物二苯并噻吩和4,6-二甲基二苯并噻吩在各类催化剂上加氢脱硫的反应路径,比较了这两种模型含硫化合物的直接脱硫（DDS）和先加氢再脱硫（HYD）路径相对快慢的影响因素。详细综述了假1级、假2级、快慢1级、n级、L-H以及抑制剂H2S存在下的动力学模型在描述二苯并噻吩类模型化合物及真实油品的加氢脱硫过程中的研究现状,介绍了神经网络在柴油加氢动力学和脱硫率预测方面的研究进展。还对催化精馏、并流-逆流滴流床、两相床反应器等新型加氢脱硫反应器的最新发展作了综述,展望了加氢脱硫动力学及反应器的研究方向和面临的挑战。     

固定化酶反应器及其在蛋白质组研究中的应用

综述了近年来国内外酶固定化载体的研究进展,侧重于无机材料和有机聚合物材料上的固定化酶方法;此外,也介绍了固定化胰蛋白酶反应器与分离系统联用在蛋白质样品分析中的应用,并展望了固定化酶反应器的研究方向及其在蛋白质组中的应用前景。     

Materials engineering for optoelectronic crystals related to III–V compounds

An introductory glimpse of modern approaches to the application of productive and reasonable techniques for the defined electronic materials will be presented. The paper is divided into four parts. Each is supplemented with illustrations. The first part explains the meaning of materials engineering for electronics (MEE) and for optoelectronic crystals in particular. Its interdisciplinarity is shown and also the range of problems it can solve. Graduate courses of someMEE disciplines are also given. The second part of the paper related to the feasible solution withMEE as to the optimal realization of the application requirements. The physical modelling, databases and characterization techniques are given. The third part deals with particular materials: III–V semiconductors. A brief survey of the best methods of crystal growth is given, stressing those which imply a possibility of creating crystals defined up to the atomic range. The last part is devoted to our team's orginal crystal growth methods:CAM-S (A Crystallization Method Providing Composition Autocontrol in Situ) andCOM-S (Calculation Method of Optimal Molten-Solution Composition). The combination of these methods, further modified with vibrational and magneto-hydrodinamical stirring (VS, MHD-S), allows us to grow crystalline ingots of ternary solid solutions (TSS) possessing extreme homogeneity. Illustrations on In?Ga?Sb system are supplied. We conclude with a discussion of the impact of such methods and approaches on a device quality and to other fields.     

Eco-Friendly Nitrogen-Doped Graphene Preparation and Design for the Oxygen Reduction Reaction

Four N-doped graphene materials with a nitrogen content ranging from 8.34 to 13.1 wt.% are prepared by the ball milling method. This method represents an eco-friendly mechanochemical process that can be easily adapted for industrial-scale productivity and allows both the exfoliation of graphite and the synthesis of large quantities of functionalized graphene. These materials are characterized by transmission and scanning electron microscopy, thermogravimetry measurements, X-ray powder diffraction, X-ray photoelectron and Raman spectroscopy, and then, are tested towards the oxygen reduction reaction by cyclic voltammetry and rotating disk electrode methods. Their responses towards ORR are analysed in correlation with their properties and use for the best ORR catalyst identification. However, even though the mechanochemical procedure and the characterization techniques are clean and green methods (i.e., water is the only solvent used for these syntheses and investigations), they are time consuming and, generally, a low number of materials can be prepared, characterized and tested. In order to eliminate some of these limitations, the use of regression learner and reverse engineering methods are proposed for facilitating the optimization of the synthesis conditions and the materials’ design. Thus, the machine learning algorithms are applied to data containing the synthesis parameters, the results obtained from different characterization techniques and the materials response towards ORR to quickly provide predictions that allow the best synthesis conditions or the best electrocatalysts’ identification.     

Characterization of nuclear fuels by ICP mass-spectrometric techniques

Isotopic analyses of radioactive materials such as irradiated nuclear fuel are of major importance for the optimization of the nuclear fuel cycle and for safeguard aspects. Among the mass-spectrometric techniques available, inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry are the most frequently applied methods for nuclear applications. Because of the low detection limits, the ability to analyze the isotopic composition of the elements and the applicability of the techniques for measuring stable as well as radioactive nuclides with similar sensitivity, both mass-spectrometric techniques are an excellent amendment to classical radioactivity counting methods. The paper describes selected applications of multicollector ICP-MS in combination with chromatographic separation techniques and laser ablation for the isotopic analysis of irradiated nuclear fuels. The advantages and limitations of the selected analytical technique for the characterization of such a heterogeneous sample matrix are discussed.     

An Overview of Important Microstructural Distributions for Polyolefin Analysis

Summary: Polyolefins with complex microstructures are becoming increasingly common in academic and industrial applications. Polyolefin analytical techniques are evolving to provide a more detailed picture of these microstructures, with the development and improvement of hyphenated-techniques and cross-fractionation methods. These modern analytical techniques provide a wealth of information on polyolefin microstructure and, despite being extremely useful, they can also be hard to interpret without the help of mathematical models that link polymerization kinetics to chain microstructure and polymer characterization results. In this paper we review some of the most important distributions for polyolefin microstructure and derive a few new expressions that help understand the results obtained with several polyolefin characterization techniques.     

Polymer nanocomposite membranes and their application for flow catalysis and photocatalytic degradation of organic pollutants

The modern world essentially needs a chemical industry that can operate with reduced production costs, and produce high-quality products with low environmental impact. The polymer nanocomposite-based flow catalytic membrane reactor where the reaction and separation can be amalgamated in one unit is considered as one of the new alternative solutions to solve these problems. In this review, we have discussed state-of-the-art flow-through catalytic reactors based on polymer nanocomposite membranes. The unique advantages of flow catalysis include uninterrupted operation, good recyclability, and reaction product without contamination that leads to simple purification. Various catalytic model reactions such as coupling, hydrogenation, esterification in the flow system are presented. We have also presented an overview of methods adopted for preparing such nanocomposite membranes. In the last section, a discussion has been made on the recent advances on polymer-based nanocomposite membranes for the degradation and separation of organic pollutants.     

Perovskite ceramics and recent experimental progress in reactor design for chemical looping combustion application

Chemical looping combustion (CLC) is a novel method of carbon capture and sequestration. It facilitates CO₂ capture by lower energy penalties compared with other methods in this category. The major challenges encountered in CLC are oxygen carrier, reactor and fuel-type selection. A proper combination of these factors is required for an efficient CLC. There have been several studies with regard to oxygen carriers applicable to these processes: novel oxygen carriers, single perovskites and potential oxygen carriers, double perovskites, have been investigated for their oxygen capture and release properties in a number of studies. Different kinds of reactors have also been proposed for use in CLC processes. This paper presents information on the materials capable of oxygen storage and release and the different kinds of reactors investigated for CLC in different studies. It has been shown that, although there are several oxygen carriers and reactors with the desired function and efficiency for CLC, there remains the need for further improvement and optimisation in both areas. © 2014 Institute of Chemistry, Slovak Academy of Sciences     

A model for ultrafine powder production in a plasma reactor

A model is proposed for the analysis of the production of ultrafine particles in thermal plasma reactors. The model initially solves the fluid flow, temperature, and concentration fields using a classical control volume approach. The nucleation and growth of ultra fine particles are then solved along each streamline. The evolution of the particle distribution is described by a statistical approach, using the first moments of the distribution as the dependent variables. Brownian coalescence is considered in the free molecular regime. In the discussion, the model is used to demonstrate the effects of some important parameters, such as the initial concentration of metal vapor, its radial distribution, and the radial injection of a cooling gas, on the particle size distribution.     

Photosensitive polyimides for applications in electrical and optical interconnection technology

The application of photosensitive polyimides in electrical and optical interconnection technology is discussed. Critical properties of two photosensitive polyimide formulations with significantly different structural chemistries have been compared. Polyamic ester based formulations such as Selectilux® HTR3 show significant distortions in the photopatterned features upon high-temperature baking, which can be ascribed to anisotropic shrinkage. A BTDA-alkylated diamine based preimidized formulation (Probimide®), on the other hand, shows a more uniform shrinkage of the photopatterned features. HTR3 films interacts strongly with metals such as copper, which adversely affect the photopatternability of these materials. Planarization behavior in multiple layer structures has also been investigated. We explored the viability of these materials for applications in optical interconnection. Probimide® materials exhibit low scattering losses and appear to be promising candidates for the development of a MCM-compatible optical interconnection technology. We also describe here a novel technique for optical recording of refractive index patterns in Probimide® films.     

生产99Mo、131I和89Sr医用同位素的水溶液堆

99Mo1、31I和89Sr等医用同位素对人类健康和医学的发展具有非常重要的作用。与靶辐照反应堆相比,用水溶液堆生产99Mo1、31I和89Sr具有安全性好,结构简单,经济价值高,无靶件制备、溶解工艺,产生废物少等优点,用水溶液堆生产医用同位素具有很好的发展前景。由于多堆芯水溶液堆、高功率水溶液堆均能显著提高产率,低富集度235U水溶液堆符合核不扩散条约中对235U浓缩度的要求,因此这三种堆是水溶液堆未来的发展方向。     

Molecular cluster building algorithm: electrostatic guidelines and molecular tailoring approach

Nano-sized clusters of various materials are recent experimental targets, since they exhibit size-dependent physico-chemical properties. A vast amount of literature is available on the study of molecular clusters but general methods for systematic evolution of their growth are rather scarce. The present work reports a molecular cluster building algorithm based on the electrostatic guidelines, followed by ab initio investigations, enabled by the application of molecular tailoring approach. Applications of the algorithm for generating geometries and interaction energies of large molecular clusters of zinc sulfide, benzene, and water are presented.     

Ultratrace and microdistribution analysis in material sciences

Summary All-rounders and experts are two basic types of scientists. A harmonic cooperation between these two groups is essential for today's large study groups engaged in materials development. Materials development programmes in many high-tech countries are major fields of research supported by special financial arrangements (e.g. COST, EURAM or BRITE-programmes in Europe). Modern materials development is not possible without analytical guidance. This is not always realized by all engaged partners and it is a main obligation of analytical chemists to make aware of the role of a potent materials characterization in relevant development programmes. This should be demonstrated in two essential relevant areas: a) Bulk trace and ultra trace analysis of metals. Many important metal properties are directly or indirectly influenced by trace elements. In complex systems like fusion reactors or microelectronic components, trace contents of even minor metal parts might decisively influence system properties. As refractory metals and their silicides gain rising importance in VLSI microelectronic applications, their ultratrace characterization becomes a major challenge. Essential progress was possible by the complementary application of mass-spectrometric methods. Latest results and a critical survey will be given, including GDMS, SIMS, SSMS, IDMS and ICP-MS.Surprisingly, however, highest sensitivities and best detection limits were recently achieved by a combination of trace-matrix separation procedures and final end determination with ICP-MS. This combination also proved to be the most economic and safest approach from the view point of accuracy and precision. b) The analytical characterization of discontinuities and heterogeneities in solid matter. Practical examples are again taken from the study of refractory and hard metals and ceramics. A survey is given as to the manifold effects, heterogeneities and discontinuities exert on modern high-tech materials: as a function of their average diameter, they can either strengthen the material (dispersion strengthening), or they can cause deterioration of material properties e.g. as points of crack initiation, by grain boundary embrittlement etc. Together with most important methods for detection and characterization of heterogeneities and discontinuities, their evaluation and possible prevention during materials fabrication are discussed and pertinent examples are given. The phenomena of heterogeneous particles and pores are elucidated in more detail.

Acronyms used

1 Abbreviations for European research programmes AGATA Advanced Gas Turbines for Automobiles - BRITE Basic Research for Industrial Technologies for Europe - COST Cooperation in Science and Technology - EURAM European Research Activities Programme on Materials 2 Abbreviations in the field of refractory metals technology ADM Ammonium-Di-Molybdate - APT Ammonium-Para-Tungstate - HP High Purity - MHC Molybdenum-based alloy containing 1.2% Hf and 0.1% C - NS Non-sag (tungsten, used for lamp filaments and evaporative metallization techniques) - ODS Oxide Dispersion Strengthened - RM Refractory Metal - TZM Molybdenum-base alloy containing 0.5% Ti, 0.08% Zr and 0.025% C - UHP Ultra High Purity - VLSI Very large scale integration - ZHM Molybdenum-base alloy containing 0.40% Zr, 1.2% Hf and 0.15% C 3 Analytical technique names AA Activation Analysis - AAS Atomic Absorption Spectrophotometry - AES Auger Electron Spectrometry or Atomic Emission Spectrometry (only used in this work where it is clear that Auger Electron Spectrometry is not meant) - EDX(RS) Energy Dispersive X-Ray Spectrometry - EELS Electron Energy Loss Spectrometry - EP(X)MA Electron Probe X-Ray Microanalysis - GDMS Glow Discharge Mass Spectrometry - GFAAS Graphite Furnace Atomic Absorption Spectrometry - ICP-OES, MS Inductively Coupled Plasma — Optical Emission Spectrometry, Mass Spectrometry - ID-MS Isotope Dilution — Mass Spectrometry - LAS Classical photometry (Liquid Absorption — Spectrophotometry) - LEED Low Energy Electron Diffraction - MS Mass Spectrometry - NAA Neutron Activation Analysis - OES Optical Emission Spectrometry - SEM Scanning Electron Microscopy - SIMS Secondary Ion Mass Spectrometry - SSMS Spark Source Mass Spectrometry - TEM Transmission Electron Microscopy - TMS Trace-Matrix Separation (procedure) - WLD(-XRS) Wave Length Dispersive — XRS - XR(F)S X-Ray (Fluorescence) Spectrometry     

多空间尺度下的金属锂负极表征技术

金属锂因为其优秀的特性被认为是未来锂电池负极的最终之选。然而目前金属锂负极在旧有液态体系中的研究陷入瓶颈,在新兴固态体系中的挑战层出不穷。想要实现金属锂负极的实用化,必须加深对金属锂负极基础科学问题的认识。本文系统论述了多空间尺度下金属锂的电极行为与对应的表征技术。首先综述了多空间尺度下金属锂负极的基础科学和应用技术问题,结合近年来的工作,对全空间尺度下的先进表征手段做了梳理,分析了从原子级到宏观尺度各种表征手段的技术特点,并重点讨论了各类表征技术在研究固态体系中金属锂负极时的特点与可能的发展方向。