检索结果-南通市图书馆

Mechanically induced phase transformation of zinc sulfide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2015年第1期13卷 1-10页

作者： Cornelia Damm Patrick Armstrong Christian Roβkopf Stefan Romeis wolfgang peukert University Erlangen-Nuremberg Institute of Particle Technology

Molecular dynamics （MD） simulations of the consecutive compression-decompression cycles ot hexagonal zinc sulfide （wurtzite） nanoparticles predict an irreversible phase transformation to the cubic *** phase transformation commences at the contact area between the particle and the inden- ter and proceeds with the number of compression cycles. Dislocations are visible for a particle size above 5nm. Results from wet grinding and dry powder compression experiments on a commercial wurtzite pigment agree qualitatively with MD simulation predictions. X-ray diffraction patterns reveal that the amount of cubic polymorph in the compressed samples increases with pressure applied to the powder. In comparison with powder compression, wet milling leads to a more pronounced phase transformation. This occurs because the particles are exposed to a large number of stress events by collision with the grinding media, which leads to the formation of defects and new surface crystallites by particle fracture. According to the MD simulations, phase transformation is expected to occur preferentially in surface crystallites because they experience the highest mechanical load. Because of the phase transformation, the wet ground and compressed samples exhibit a lower photo- luminescence intensity than the feed material. In comparison with powder compression, milling reduces the photoluminescence intensity more substantially. This occurs because a higher defect concentration is formed. The defects contribute to the phase transformation and photoluminescence quenching.

关键词： Polymorph transformationZinc sulfide Molecular dynamics simulation Wet milling Powder compression

Assessing stress conditions and impact velocities in fluidized bed opposed jet mills

在线全文

学校读者我要写书评

暂无评论

Particuology 2020年第6期18卷 12-22页

作者： Alexander Strobel Benedikt Koninger Stefan Romeis Florian Schott Karl-Ernst Wirth wolfgang peukert Institute of Particle Technology(LFG) Friedrich-Alexander-Universitat Erlangen-NiirnbergCauerstrae 491058 ErlangenGermany

Fluidized bed opposed jet mills are capable of meeting the continuously growing dema nd for contamination-free fine *** this type of jet mill,the solid material is entrained and accelerated by expanding gas jets that are focused onto a focal point in side a fluidized *** resulting particle collisions induce *** process is affected by the relative particle velocities and the number of particle-particle ***,both quantities are ***,to date,neither relative particle velocities nor collision frequencies in such units have been *** present work introduces an innovative method to assess the stressing conditions in jet mills *** this end,mixtures of glass and ductile metal microspheres were used,with the latter employed in small ***-particle collisions between the aluminum and glass spheres lead to the formation of dents on the *** size and number of these dents are associated with the individual collision velocities and overall collision *** correlation between dent size and collision velocity was obtained from finite element calculations based on empirical *** proposed approach was validated using particle image velocimetry during secondary gas injection into a fluidized bed *** this case the effect of the distance between two opposed nozzles was *** a lab-scaled fluidized bed opposed jet mill the effects of gas pressure and hold-up were *** particle velocities were found to be sign ificantly lower tha n the gas velocities,while the nu mber of contacts per particle was determined to be extremely high.

关键词： Fluidized bed opposed jet mill Single particle probes Finite element modeling Stress number distribution Relative velocity distribution

Determination of quantitative structure-property and structure-process relationships for graphene production in water

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2015年第6期8卷 1865-1881页

作者： Thomas J. Nacken Cornelia Damm Haichen Xing Andreas ROger wolfgang peukert Institute of Particle Technology (LFG) Friedrich-Alexander University Erlangen-NOrnberg (FAU) Cauerstrasse 4 91058 Erlangen Germany

为 graphene 和很少层 graphene (FLG ) 的一个可伸缩的方法由在 nonionic 表面活化剂 TWEEN 的水的答案的石墨分层的生产 ?(TW80 ) 80 用搅动媒介的工厂被介绍。用统计拉曼光谱学的 Delaminated 产品分析产出揭示了怎么强调紧张和特定... 详细信息

为 graphene 和很少层 graphene (FLG ) 的一个可伸缩的方法由在 nonionic 表面活化剂 TWEEN 的水的答案的石墨分层的生产 ?(TW80 ) 80 用搅动媒介的工厂被介绍。用统计拉曼光谱学的 Delaminated 产品分析产出揭示了怎么强调紧张和特定的精力输入的广泛的 processing-structure-property 关系，即，进程参数，管理 graphene 的收益生产和缺点形成。驱散的碳集中增加了，但是内容和 FLG 产品的质量与更高特定的精力输入严厉地减少了。产品的 FLG 内容直到 90% ，特别为低特定的精力输入。而且，拉曼分析表明比大约 1 nJ 大的压力紧张与在产品粒子的重要缺点形成有关。为 graphene 生产的另一个关键参数是溶剂粘性。当溶剂粘性从 1 ～ 6 mPa 被增加时，在产品的 FLG 集中由 10

关键词：定量结构水溶液石墨生产性质非离子表面活性剂产品分析能量输入

UNDERSTANDING PARTICLE INTERACTIONS FROM A MICROSCOPIC VIEW OF PARTICULATE INTERFACES

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Particuology 2005年第1期3卷 14-18页

作者： wolfgang peukert Martin Goetzinger Institute of Particle Technology University of ErlangenGermany

Particle interactions are of crucial importance in many applications including fluidized beds and other powder handling systems. The present contribution discusses how surface properties of the particles can be determined in order to get quantitative information on particle interactions. For instance, we apply adsorption experiments in order to get information on dispersive and polar interactions. These measurements are complemented by careful roughness measurements as well as FTIR-spectroscopy and TG-MS analysis. Adhesion force measurements with AFM and ultra-centrifuge on well defined ideal as well as heterogeneous surfaces led to the introduction of three generic types of adhesion force distributions: monomodal Weibull, bimodal Weibull and lognormal. The influence of roughness and adsorbed layers on adhesion are shown. In addition, we discuss important aspects of the dynamic nature of the adhesion/detachment process by means of MD-simulations.

关键词： particle interaction adhesion adsorption molecular dynamics

Suspension- and powder-based derivation of Hansen dispersibility parameters for zinc oxide quantum dots

在线全文

学校读者我要写书评

暂无评论

Particuology 2019年第3期17卷 71-79页

作者： Sebastian Siüβ Wei Lin Olga Getmanenko Lukas Pflug Titus Sobisch wolfgang peukert Dietmar Lerche Doris Segets Institute of Particle Technology (LFG) Friedrich-Alexander-Universitat Erlangen-Niimberg (FAU) Cauerstr. 4 91058 Erlangen Germany Interdisciplinary Center for Functional Particle Systems (FPS) Friedrich-Alexander-Universitat Erlangen-Niimberg (FAU) HaberstraJSe 9a 91058 Erlangen Germany Institute of Applied Mathematics 2 Friedrich-Alexander-Universitat Erlangen-Nümberg (FAU) Cauerstrajβe 11 91058 Erlangen Germany LUM GmbH Justus-von-Liebig StraJSe 3 12489 Berlin Germany Process Technology for Electrochemical Functional Materials Institute for Combustion and Gas Dynamics - Reactive Fluids (1VG) University Duisburg-Essen (UDE) Carl-Benz-StraJSe 199 47057 Duisburg Germany

For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility parameters (HSP) was initially invented to describe the interactions of (polymer) molecules and their solubility in different liquids and is increasingly being used in particle technology to describe dispersibility. Because dispersions are not thermodynamically stable, the term Hansen dispersibility parameters (HDP) is used instead of HSP (SiiE, Sobisch, peukert, Lerche,& Segets, 2018). Herein, we extend a previously developed standardized and non-subjective method for determination of Hansen parameters based on analytical centrifugation to the important class of quantum materials. As a technically relevant model system, zinc oxide quantum dots (QDs) were used to transfer our methodology to nanoparticles (NPs) with sizes below lOnm. The results obtained using the standard procedure starting from a dried powder were compared with those obtained through redispersion from the wet sediment produced during the typical washing procedure of QDs, and drying was observed to play an important role. In conclusion, our study reveals the high potential of HDP for quantifying the interfacial properties of NPs as well as their link to dispersibility.

关键词： Hansen solubility parameter Functionalization Semiconductor nanoparticles Colloidal stability Quantum material

PRODUCT ENGINEERING OF PARTICULATE SOLIDS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Particuology 2005年第1期3卷 133-133页

作者： wolfgang peukert Institute of Particle Technology Friedrich-Alexander University Erlangen-Nuremberg D 91058 Erlangen Germany

An important development in Particle Technology is directed towards tailored product properties, i.e. product engineering. Product properties are strongly related to the disperse properties of the particles, i.e. their size, shape, morphology and surface. We discuss some general applicable principles in product engineering and give various examples. Strongly related to this approach are methods to characterize and to tailor product and particle properties. For systems which are controlled by the interfaces (e.g. particles in the micron size range and below) we apply a multi-scale approach from the particulate interfaces over particle interactions to the macroscopic properties. Thus, we tailor macroscopic product properties through microscopic control of the interfaces. This approach must be complemented by methods to characterize particle and product properties. It is shown that by careful consideration of the underlying physical processes considerable progress can be achieved.

关键词： particle properties physical processes

PARTICLE PROPERTIES——PROMISE AND NEGLECT

在线全文

学校读者我要写书评

暂无评论

China Particuology 2003年第1期1卷 13-19页

作者： wolfgang peukertInstitute of Particle Technology, Friedrich-Alexander-University Erlangen-Nuremberg, Cauerstr. 4 , 91058 Erlangen, GermanyE-mail: W. peukert@mvt. uni-erlangen. de Institute of Particle Technology Friedrich-Alexander-University Erlangen-Nuremberg Cauerstr. 4 91058 Erlangen Germany

We see two major trends in Particie Technology. First, the focus is shifted from unit operations towards functional products, i.e. towards product engineering. Second, modeling will become more and more important. Proc-esses cannot yet be designed from basie molecular understanding. Nanotechnology, however, begins to bridge this gap between molecules and particles and may thus open new ways not only for the production and handling of particulate matter but also for the engineered design of advanced material properties. Starting from the concept of product engineering we investigate the basie preconditions for tailoring nanoparticulate properties, i.e. the control of the particie in-teractions. Nanotechnology can only be transferred to industrial production if the interactions are effectively controlled.Material and particie properties are essential for predictive models. Although strong tools like MD, DEM or population balance models are available, these models are only predictive if realistic material and particie properties are available which is often not the case. We show for selected examples how particie properties can be obtained by studying the physically relevant elementary processes. The impact breakage behavior of many different materials is described by a master curve. Particie adhesion can be modeled if the roughness of particie and substrate and the Hamaker constant are known. The latter is obtained from adsorption studies.

关键词： product engineering nanoparticles surface forces comminution adhesion

Salinity Stress in Roots of Contrasting BarleyGenotypes Reveals Time-Distinct and Genotype-Specific Patterns for Defined Proteins

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2014年第2期7卷 336-355页

作者： Katja Witzel Andrea Matros Marc Strickert Stephanie Kaspar Manuela peukert Karl H. Mühling Andreas Börner Hans-Peter Mock Leibniz Institute of Plant Genetics and Crop Plant Research Corrensstrasse 3 06466 Gatersleben Germany Present address: Leibniz Institute of Vegetable and Ornamental Crops Theodor-Echtermeyer-Weg 1 14979 Großbeeren Germany Present address: University of Siegen Media Systems Group Hölderlinstrasse 3 57068 Siegen Germany Present address: Bruker Daltonik GmbH Fahrenheitstrasse 4 28359 Bremen Germany Institute of Plant Nutrition and Soil Science Christian Albrechts University Hermann-Rodewald-Strasse 2 24118 Kiel Germany

Soil salinity is one of the most severe abiotic stress factors threatening agriculture worldwide. Hence,particular interest exists in unraveling mechanisms leading to salt tolerance and improved crop plant performance onsaline soils. Barley is considered to be one of the most salinity-tolerant crops, but varying levels of tolerance are wellcharacterized. A proteomic analysis of the roots of two contrasting cultivars （cv. Steptoe and cv. Morex） is *** plants were exposed to a period of 1, 4, 7, or 10 d at 0, 100, or 150mM NaCI. The root proteome was analyzedbased on two-dimensional gel electrophoresis. A number of cultivar-specific and salinity stress-responsive proteins wereidentified. Mass spectrometry-based identification was successful for 74 proteins, and a hierarchical clustering analysisgrouped these into five clusters based on similarity of expression profile. The rank product method was applied to sta-tistically access the early and late responses, and this delivered a number of new candidate proteins underlying salinitytolerance in barley. Among these were some germin-like proteins, some pathogenesis-related proteins, and numerousas-yet uncharacterized proteins. Notably, proteins involved in detoxification pathways and terpenoid biosynthesis weredetected as early responsive to salinity and may function as a means of modulating growth-regulating mechanisms andmembrane stability via fine tuning of phytohormone and secondary metabolism in the root.

关键词： barley genotypes mass spectrometry proteome analysis salinity stress two-dimensional gel electrophoresis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

可持续低温漂白技术

国际纺织导报 2017年第1期45卷 28-28,30-32页

作者： A.Mehlhorn S.Mobius A.Knoblauch M.peukert 刘蒙稣(译) 程心怡(译) 罗艳(校) Zschimmer&Schwarz Mohsdorf公司德国不详

织物预处理在纺织品整理过程中起着关键作用,这不仅在于它可为高品质的最终产品提供基础,还在于其对环境的影响。纺织品的常规漂白是在高工艺温度条件下进行的,涉及到大量的水、废水及能源。为保护环境,通过采用Zschimmer & Schwarz Moh... 详细信息

织物预处理在纺织品整理过程中起着关键作用,这不仅在于它可为高品质的最终产品提供基础,还在于其对环境的影响。纺织品的常规漂白是在高工艺温度条件下进行的,涉及到大量的水、废水及能源。为保护环境,通过采用Zschimmer & Schwarz Mohsdorf公司开发的生态且经济的Cold White低温漂白技术,可实现对能源与资源的环保利用。

关键词：低温漂白 Cold White 可持续织物预处理