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Author: Martin Dienwiebel
Publisher: Springer
ISBN: 3319998978
Category : Technology & Engineering
Languages : en
Pages : 332
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Book Description
This book presents the basics and methods of nanoscale analytical techniques for tribology field. It gives guidance to the application of mechanical, microstructural, chemical characterization methods and topography analysis of materials. It provides an overview of the of state-of-the-art for researchers and practitioners in the field of tribology. It shows different examples to the application of mechanical, microstructural, chemical characterization methods and topography analysis of materials. Friction and Wear phenomena are governed by complexe processes at the interface of sliding surfaces. For a detailed understanding of these phenomena many surface sensitive techniques have become available in recent years. The applied methods are atom probe tomography, in situ TEM, SERS, NEXAFS, in situ XPS, nanoindentation and in situ Raman spectroscopy. A survey of new related numerical calculations completes this book. This concerns ab-initio coupling, numerical calculations for mechanical aspects and density functional theory (DFT) to study chemical reactivity.
Author: Martin Dienwiebel
Publisher: Springer
ISBN: 3319998978
Category : Technology & Engineering
Languages : en
Pages : 332
Get Book Here
Book Description
This book presents the basics and methods of nanoscale analytical techniques for tribology field. It gives guidance to the application of mechanical, microstructural, chemical characterization methods and topography analysis of materials. It provides an overview of the of state-of-the-art for researchers and practitioners in the field of tribology. It shows different examples to the application of mechanical, microstructural, chemical characterization methods and topography analysis of materials. Friction and Wear phenomena are governed by complexe processes at the interface of sliding surfaces. For a detailed understanding of these phenomena many surface sensitive techniques have become available in recent years. The applied methods are atom probe tomography, in situ TEM, SERS, NEXAFS, in situ XPS, nanoindentation and in situ Raman spectroscopy. A survey of new related numerical calculations completes this book. This concerns ab-initio coupling, numerical calculations for mechanical aspects and density functional theory (DFT) to study chemical reactivity.
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 884
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Book Description
Author: National Research Council
Publisher: National Academies Press
ISBN: 030916463X
Category : Science
Languages : en
Pages : 222
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Book Description
Scientists and engineers have long relied on the power of imaging techniques to help see objects invisible to the naked eye, and thus, to advance scientific knowledge. These experts are constantly pushing the limits of technology in pursuit of chemical imagingâ€"the ability to visualize molecular structures and chemical composition in time and space as actual events unfoldâ€"from the smallest dimension of a biological system to the widest expanse of a distant galaxy. Chemical imaging has a variety of applications for almost every facet of our daily lives, ranging from medical diagnosis and treatment to the study and design of material properties in new products. In addition to highlighting advances in chemical imaging that could have the greatest impact on critical problems in science and technology, Visualizing Chemistry reviews the current state of chemical imaging technology, identifies promising future developments and their applications, and suggests a research and educational agenda to enable breakthrough improvements.
Author: Alan M. Spool
Publisher: Momentum Press
ISBN: 1606507745
Category : Technology & Engineering
Languages : en
Pages : 267
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Book Description
Time of flight secondary ion mass spectrometry, TOF-SIMS, is a highly surface sensitive analytical technique that provides information about composition with submicron lateral resolution. For select materials, TOF-SIMS provides unparalleled sensitivity along with excellent reproducibility, and as a mass spectrometric technique, it also provides excellent specificity. Of the analytical methods available, it is among the most surface sensitive, but the physical principles that underlie it are also the least understood. This volume describes the instrumentation, the physical principles behind the technique to the extent they are understood, and provides a practical approach for the interpretation of TOF-SIMS data. The use of advanced data processing methods such as multivariate statistics are described in a readily approachable manner. Given a basic background in undergraduate chemistry and physics, the book will be of use to any student with an interest in the technique.
Author: J. C. Vickerman
Publisher: IM Publications
ISBN: 1906715173
Category : Mass spectrometry
Languages : en
Pages : 742
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Book Description
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is the most versatile of the surface analysis techniques that have been developed during the last 30 years. This is the Second Edition of the first book ToF-SIMS: Surface analysis by Mass Spectrometry to be dedicated to the subject and the treatment is comprehensive
Author: Sarah Fearn
Publisher: Morgan & Claypool Publishers
ISBN: 1681740885
Category : Technology & Engineering
Languages : en
Pages : 67
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Book Description
This book highlights the application of Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) for high-resolution surface analysis and characterization of materials. While providing a brief overview of the principles of SIMS, it also provides examples of how dual-beam ToF-SIMS is used to investigate a range of materials systems and properties. Over the years, SIMS instrumentation has dramatically changed since the earliest secondary ion mass spectrometers were first developed. Instruments were once dedicated to either the depth profiling of materials using high-ion-beam currents to analyse near surface to bulk regions of materials (dynamic SIMS), or time-of-flight instruments that produced complex mass spectra of the very outer-most surface of samples, using very low-beam currents (static SIMS). Now, with the development of dual-beam instruments these two very distinct fields now overlap.
Author: Jacek Grams
Publisher: Nova Publishers
ISBN: 9781600216350
Category : Science
Languages : en
Pages : 292
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Book Description
This book presents the latest trends and applications of time-of-flight secondary ion mass spectrometry (ToF-SIMS). It includes research and applications of the new primary ion guns. It also describes new possibilities of mass spectrometers and instrumentation development.
Author: Michael Nastasi
Publisher: CRC Press
ISBN: 1439846383
Category : Science
Languages : en
Pages : 476
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Book Description
Ion Beam Analysis: Fundamentals and Applications explains the basic characteristics of ion beams as applied to the analysis of materials, as well as ion beam analysis (IBA) of art/archaeological objects. It focuses on the fundamentals and applications of ion beam methods of materials characterization. The book explains how ions interact with solids and describes what information can be gained. It starts by covering the fundamentals of ion beam analysis, including kinematics, ion stopping, Rutherford backscattering, channeling, elastic recoil detection, particle induced x-ray emission, and nuclear reaction analysis. The second part turns to applications, looking at the broad range of potential uses in thin film reactions, ion implantation, nuclear energy, biology, and art/archaeology. Examines classical collision theory Details the fundamentals of five specific ion beam analysis techniques Illustrates specific applications, including biomedicine and thin film analysis Provides examples of ion beam analysis in traditional and emerging research fields Supplying readers with the means to understand the benefits and limitations of IBA, the book offers practical information that users can immediately apply to their own work. It covers the broad range of current and emerging applications in materials science, physics, art, archaeology, and biology. It also includes a chapter on computer applications of IBA.
Author: Jan Lindström
Publisher: Linköping University Electronic Press
ISBN: 917929684X
Category : Electronic books
Languages : sv
Pages : 61
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Book Description
A phosphor or scintillator is a material that will emit visible light when struck by ionising radiation. In the early days of diagnostic radiology, it was discovered that the radiation dose needed to get an image on a film, could be greatly reduced by inserting a fluorescent layer of a phosphor in direct contact with the film. Thus, introducing the step of converting the ionising radiation to light in a first step. Going forward in time, film has been replaced with photodetectors and there is now a variety of imaging x-ray systems, still based on phosphors and scintillators. There is continuous research going on to optimise between the radiation dose needed and a sufficient image quality. These factors tend to be in opposition to each other. It is a complicated task to optimise these imaging system and new phosphor materials emerges regularly. One of the key factors is the efficiency of the conversion from xrays to light. In this work this is denoted “extrinsic efficiency”. It is important since it largely determines the final dose to the patient needed for the imaging task. Most imaging x-ray detectors are based on phosphor or scintillator types where their imaging performance has been improved through tweaking of various parameters (light guide structure, higher density, light emission spectrum matching to photodetectors, delayed fluorescence quenching etc) One key factor that largely determines the extrinsic efficiency of a specific phosphor is the particle size. Larger particles result in a higher luminance of the phosphor for the same radiation dose as does as a thicker phosphor layer (to a limit). There exists already a battery of models describing various phosphor qualities. However, particle size and thickness have not been treated as a fully independent variables in previous model works. Indirectly, the influence of these parameters is accounted for, but the existing models were either considered too general, containing several complex parameters and factors to cover all kind of cases or too highly specialised to be easily applicable to fluorescent detectors in diagnostic radiology. The aim of this thesis is therefore to describe and assess a simple model denoted the “LAC-model” (after the original authors Lindström and Alm Carlsson), developed for a fluorescent layer using individual sub-layers defined by the particle size diameter. The model is thought to be a tool for quickly evaluating various particle size and fluorescent layer thickness combinations for a chosen phosphor and design. It may also serve as a more intuitive description of the underlying parameters influencing the final extrinsic efficiency. Further tests affirmed the validity of the model through measurements. The LACmodel produced results deviating a maximum of +5 % from luminescence measurements. During the development of the model various assumptions and simplifications were made. One assumption was the absence of a so called “dead layer”. This is a layer supposedly surrounding each particle decreasing the efficiency of converting x-rays to light. It is not completely “dead” as in inactive but is thought to have a reduced efficiency. This phenomenon was struggled with, when historically designing electron beam stimulated phosphors for various applications (i.e. displays, TV tubes etc). There are also articles reporting dead layer influence for x-ray detectors (usually spectrometers i.e. not for imaging). By introducing a dead layer in the LAC-model the effect of the layer was investigated and was found to result in a change of less than 8% for the extrinsic efficiency. It was also noted that sometimes a dead layer effect may emerge at surfaces of a scintillator slab but not necessarily connected to the phosphor particles themselves. Due to differences between phosphor material and the surroundings, an interface effect arose to compete with the process of inherent dead layers of the individual particles. It was found to be mostly negligible for x-rays in the studied energy and material range. However, an effect was shown for electrons as incident ionising radiation which could shed some light on the strangely neglected apparent dead layer created this way. Finally, applications, one involving developing a prototype for checking the light field radiation field coincidence, were evaluated for overall performance and the optimisation level of the applied fluorescent layer. Interesting findings were made during the development process: for the first time to the knowledge of the author, focus shift wandering was quantified in the corresponding movement of the x-ray field edge and a non-trivial discussion on the concept of an apparent light field edge resulted in a modified definition of the same. En fosfor eller scintillator är ett material som avger synligt ljus när det träffas av joniserande strålning. Inom diagnostisk radiologi upptäckte man i ett tidigt skede att stråldosen som behövdes för att få en bild på en röntgenfilm, reducerades kraftigt om man placerade ett fluorescerande skikt, en fosfor, i direkt kontakt med filmen. I nutid har film ersatts med fotodetektorer och det finns nu en mängd olika röntgenbildsystem men som fortfarande är baserade på fosforer och scintillatorer. Det pågår en kontinuerlig forskning för att optimera mellan erforderlig stråldos och en tillräcklig god diagnostisk bildkvalitet. Dessa faktorer tenderar att motverka varandra. Det är en komplicerad uppgift att optimera röntgenbildsystemen och nya fosformaterial dyker ständigt upp. En av de viktiga egenskaperna är fosforns omvandlingseffektivitet från röntgen till ljus. I detta arbete används benämningen ”extrinsisk (yttre) effektivitet". Denna egenskap är viktig eftersom den i stor utsträckning bestämmer den slutliga dosen till patienten som krävs för bilddiagnostiken. De flesta röntgendetektorer är baserade på fosfor- eller scintillatortyper där bildprestanda har förbättrats genom att utveckla olika parametrar (ljusledarstruktur, högre densitet, ljusemissionsspektrum som matchar fotodetektorer, minskad efterlysning etc.). En viktig faktor som i stor utsträckning bestämmer omvandlingseffektiviteten hos en specifik fosfor är partikelstorleken. Större partiklar resulterar i en högre luminescens (mer ljus) från fosforen för samma stråldos. Vilket också gäller för ett tjockare fosforlager (till en viss gräns!). Det finns redan fysikaliska modeller som beskriver olika fosforparametrar men partikelstorlek och fosfortjocklek har dock inte hanterats som fristående variabler i dessa modellarbeten. Istället har deras inverkan modellerats indirekt men det har gjort att de befintliga modellerna kan anses komplexa. De är antingen för generella som medför flera komplexa parametrar och faktorer för att täcka alla tänkbara varianter eller för specialiserade för att kunna tillämpas enkelt på fluorescerande detektorer i diagnostisk radiologi. Syftet med denna avhandling är därför att beskriva och analysera en praktisk modell betecknad ”LAC-modellen” (efter de ursprungliga författarna Lindström och Alm Carlsson). Den är utvecklad för ett fluorescerande block som består av flera underliggande skikt vars tjocklek bestäms av partiklarnas diameter. Avsikten med modellen är att den ska vara ett verktyg för att snabbt utvärdera olika varianter av partikelstorlek och tjockleks-kombinationer för en vald fosfor med i grunden samma design. Experiment har bekräftat modellens giltighet och mätresultat visar att modellresultaten avvek maximalt +5% från luminiscensmätningar. Utvecklingen av modellen krävde olika antaganden och förenklingar. Ett antagande var frånvaron av ett så kallat ”dött lager”. Det är ett skikt som antas omge varje partikel och som därför minskar omvandlingseffektiviteten från röntgen till ljus. Det är dock inte helt "dött" i meningen helt inaktivt men har en mindre förmåga att omvandla röntgen till ljus jämfört med fosforns huvudmaterial. Historisk sett har man försökt åtgärda detta fenomen under lång tid och speciellt för applikationer där man använt sig av elektronstrålar (dvs olika typer av displayer, TV-rör etc.). Just för elektroner har man sett att döda skiktet tenderar att växa med tiden. Det finns också artiklar som rapporterar en påverkan av röntgendetektorers funktion (vanligtvis dock för spektrometrar, dvs inte för avbildning). Genom att införa ett dött skikt i LAC-modellen undersöktes skiktets effekt och visade sig resultera i en förändring på mindre än 8% för effektiviteten. Det noterades också att ibland kan en dödskiktsliknande effekt uppstå vid ytor av ett scintillatorblock men inte nödvändigtvis pga. av själva fosforpartiklarnas ljusomvandlingsegenskaper. Då det uppstår skillnader mellan fosformaterialet och omgivningen får man en s.k. gränsskiktseffekt som s.a.s. konkurrerar med kemiskt döda skiktet på de enskilda partiklarna. De döda skiktens inverkan visade sig i princip försumbara för röntgenbild-detektorer - åtminstone inom det studerade energi- och materialområdet. En tydlig effekt kunde dock noteras för joniserande strålning i form av elektroner. Simuleringarna kunde ge en bättre bild av egenskaperna hos det döda skiktet som skapats på detta sätt. Slutligen utvärderades två applikationer med hjälp av LAC-modellen: en prototyp för kontroll av ljusfältets och strålfältets överenstämmelse i läge och position. Samt en etablerad produkt med samma användningsområde. I båda fallen undersöktes det fluorescerande skiktets optimeringsgrad. Intressanta resultat noterades under utvecklingsprocessen av prototypen: för första gången, så vitt författaren vet, kunde man kvantifiera röntgenrörs s.k. fokusvandring.
Author: Danica Heller-Krippendorf
Publisher: Springer Nature
ISBN: 3658285028
Category : Science
Languages : en
Pages : 207
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Book Description
Danica Heller-Krippendorf develops concepts and approaches optimizing the applicability of MVA on data sets from an industrial context. They enable more time-efficient MVA of the respective ToF‐SIMS data. Priority is given to two main aspects by the author: First, the focus is on strategies for a more time-efficient collection of the input data. This includes the optimal selection of the number of replicate measurements, the selection of input data and guidelines for the selection appropriate data preprocessing methods. Second, strategies for more efficient analysis of MVA results are presented. About the Author: Danica Heller-Krippendorf did her research and dissertation at the University of Siegen, Germany, in collaboration with a German analytical service company. Now she is engineer in analytics at a DAX company.
