Propriétés électromagnétiques de matériaux superparamagnètiques

Propriétés électromagnétiques de matériaux superparamagnètiques PDF Author: Cyrille Desmarest
Publisher:
ISBN:
Category :
Languages : fr
Pages : 154

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Book Description
Nous allons au cours de ce travail, prendre en compte la réponse d'une assemblée de particules mono domaines magnétiques à l'excitation magnétique d'une onde électromagnétique. Plus particulièrement, nous allons montrer dans le cas de particules de nickel, à partir du calcul de la perméabilité effective, que la relaxation super paramagnétique engendre des conséquences optiques observables dans la partie infrarouge du spectre. Ces calculs utilisent un modèle de milieu effectif original, le modèle "Sheng-Gadenne". Nous présentons les résultats issus de l'étude expérimentale effectuée sur des cermets de ni-al 2o 3 élaborés par co-pulvérisation. A la suite des mesures xps, qui nous ont permis d'identifier les différents éléments présents au sein des cermets fabriqués et qui suggèrent la possibilité d'une oxydation partielle du nickel détecté, nous avons pu, grâce aux nombreuses techniques de caractérisation électronique complémentaires, déterminer la nature fine des inclusions métalliques présentées notamment stem et étude en spectroscopie par perte d'énergie des électrons (eels) permettant de disposer simultanément de la résolution en énergie du spectromètre (0.5 Ev.) et de la résolution spatiale (0.6 nm) du microscope électronique. Il s'agit de grains sphéroïdes constitués d'un coeur de nickel enrobé d'une enveloppe de nickel oxyde. Les inclusions sont reparties de façon homogène dans les échantillons, et leur diamètre varie entre 3 et 8 nm environ. L'étude des propriétés magnétiques à l'aide d'un magnétomètre squid a montré qu'une telle composition est à l'origine d'un comportement magnétique anormal, cependant nous avons pu en confirmer le caractère super paramagnétique.

Propriétés électromagnétiques de matériaux superparamagnètiques

Propriétés électromagnétiques de matériaux superparamagnètiques PDF Author: Cyrille Desmarest
Publisher:
ISBN:
Category :
Languages : fr
Pages : 154

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Book Description
Nous allons au cours de ce travail, prendre en compte la réponse d'une assemblée de particules mono domaines magnétiques à l'excitation magnétique d'une onde électromagnétique. Plus particulièrement, nous allons montrer dans le cas de particules de nickel, à partir du calcul de la perméabilité effective, que la relaxation super paramagnétique engendre des conséquences optiques observables dans la partie infrarouge du spectre. Ces calculs utilisent un modèle de milieu effectif original, le modèle "Sheng-Gadenne". Nous présentons les résultats issus de l'étude expérimentale effectuée sur des cermets de ni-al 2o 3 élaborés par co-pulvérisation. A la suite des mesures xps, qui nous ont permis d'identifier les différents éléments présents au sein des cermets fabriqués et qui suggèrent la possibilité d'une oxydation partielle du nickel détecté, nous avons pu, grâce aux nombreuses techniques de caractérisation électronique complémentaires, déterminer la nature fine des inclusions métalliques présentées notamment stem et étude en spectroscopie par perte d'énergie des électrons (eels) permettant de disposer simultanément de la résolution en énergie du spectromètre (0.5 Ev.) et de la résolution spatiale (0.6 nm) du microscope électronique. Il s'agit de grains sphéroïdes constitués d'un coeur de nickel enrobé d'une enveloppe de nickel oxyde. Les inclusions sont reparties de façon homogène dans les échantillons, et leur diamètre varie entre 3 et 8 nm environ. L'étude des propriétés magnétiques à l'aide d'un magnétomètre squid a montré qu'une telle composition est à l'origine d'un comportement magnétique anormal, cependant nous avons pu en confirmer le caractère super paramagnétique.

Injectable formulations forming an implant in situ as vehicle of silica microparticles embedding superparamagnetic iron oxide nanoparticles for the local, magnetically mediated hyperthermia treatment of solid tumors

Injectable formulations forming an implant in situ as vehicle of silica microparticles embedding superparamagnetic iron oxide nanoparticles for the local, magnetically mediated hyperthermia treatment of solid tumors PDF Author: Pol-Edern Le Renard
Publisher: LE RENARD Pol-Edern
ISBN:
Category :
Languages : en
Pages : 249

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Book Description


NMR Imaging in Biomedicine

NMR Imaging in Biomedicine PDF Author: P Mansfield
Publisher: Elsevier
ISBN: 0323154069
Category : Science
Languages : en
Pages : 365

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Book Description
NMR Imaging in Biomedicine: Advances in Magnetic Resonance discusses significant advances in NMR imaging and its application to the field of biomedicine. This book is organized into 10 chapters that cover the classification, methods, imaging regimes, and the potential use of NMR imaging in medicine. After discussing the basic theoretical ideas of NMR and its application to NMR imaging, this book presents mathematical analyses of the various NMR techniques, focusing primarily on the comparison in terms of imaging speed and data-acquisition rate. It also covers a number of practical ranges or imaging regimes in terms of sensitivity, sample size, and operating frequency. Significant topics on potential application of NMR imaging in medicine, apparatus requirements in the instrumentation of NMR imaging machines, and the principles of biomagnetic effects are discussed in other chapters. The considered biomagnetic effects are categorized into three main groups: the effects of static magnetic fields, the effects of relatively slow varying time-dependent fields, and radio-frequency magnetic fields. This book is of great value to radiologists, medical physicists, neuroradiologists, anatomists, physiologists, and postgraduate students of NMR imaging.

How does MRI work?

How does MRI work? PDF Author: Dominik Weishaupt
Publisher: Springer Science & Business Media
ISBN: 3540378456
Category : Medical
Languages : en
Pages : 172

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Book Description
A succinct introduction to the physics and function of magnetic resonance imaging with an emphasis on practical information. This thoroughly revised second edition is clearly structured. The underlying physical principles of the MR experiment are described and the basic pulse sequences commonly used in clinical MRI. It progresses to more advanced techniques such as parallel imaging and cardiovascular MR imaging. An extensive glossary offers rapid access to MRI terminology and will help those seeking to understand this interesting fascinating subject.

Magnetic Resonance Imaging

Magnetic Resonance Imaging PDF Author: Vadim Kuperman
Publisher: Elsevier
ISBN: 0080535704
Category : Science
Languages : en
Pages : 197

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Book Description
This book is intended as a text/reference for students, researchers, and professors interested in physical and biomedical applications of Magnetic Resonance Imaging (MRI). Both the theoretical and practical aspects of MRI are emphasized. The book begins with a comprehensive discussion of the Nuclear Magnetic Resonance (NMR) phenomenon based on quantum mechanics and the classical theory of electromagnetism. The first three chapters of this book provide the foundation needed to understand the basic characteristics of MR images, e.g.,image contrast, spatial resolution, signal-to-noise ratio, common image artifacts. Then MRI applications are considered in the following five chapters. Both the theoretical and practical aspects of MRI are emphasized. The book ends with a discussion of instrumentation and the principles of signal detection in MRI. - Clear progression from fundamental physical principles of NMR to MRI and its applications - Extensive discussion of image acquisition and reconstruction of MRI - Discussion of different mechanisms of MR image contrast - Mathematical derivation of the signal-to-noise dependence on basic MR imaging parameters as well as field strength - In-depth consideration of artifacts in MR images - Comprehensive discussion of several techniques used for rapid MR imaging including rapid gradient-echo imaging, echo-planar imaging, fast spin-echo imaging and spiral imaging - Qualitative discussion combined with mathematical description of MR techniques for imaging flow

Magnetic Resonance Imaging

Magnetic Resonance Imaging PDF Author: Robert W. Brown
Publisher: John Wiley & Sons
ISBN: 0471720852
Category : Medical
Languages : en
Pages : 976

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Book Description
New edition explores contemporary MRI principles and practices Thoroughly revised, updated and expanded, the second edition of Magnetic Resonance Imaging: Physical Principles and Sequence Design remains the preeminent text in its field. Using consistent nomenclature and mathematical notations throughout all the chapters, this new edition carefully explains the physical principles of magnetic resonance imaging design and implementation. In addition, detailed figures and MR images enable readers to better grasp core concepts, methods, and applications. Magnetic Resonance Imaging, Second Edition begins with an introduction to fundamental principles, with coverage of magnetization, relaxation, quantum mechanics, signal detection and acquisition, Fourier imaging, image reconstruction, contrast, signal, and noise. The second part of the text explores MRI methods and applications, including fast imaging, water-fat separation, steady state gradient echo imaging, echo planar imaging, diffusion-weighted imaging, and induced magnetism. Lastly, the text discusses important hardware issues and parallel imaging. Readers familiar with the first edition will find much new material, including: New chapter dedicated to parallel imaging New sections examining off-resonance excitation principles, contrast optimization in fast steady-state incoherent imaging, and efficient lower-dimension analogues for discrete Fourier transforms in echo planar imaging applications Enhanced sections pertaining to Fourier transforms, filter effects on image resolution, and Bloch equation solutions when both rf pulse and slice select gradient fields are present Valuable improvements throughout with respect to equations, formulas, and text New and updated problems to test further the readers' grasp of core concepts Three appendices at the end of the text offer review material for basic electromagnetism and statistics as well as a list of acquisition parameters for the images in the book. Acclaimed by both students and instructors, the second edition of Magnetic Resonance Imaging offers the most comprehensive and approachable introduction to the physics and the applications of magnetic resonance imaging.

Principles of Magnetic Resonance Imaging

Principles of Magnetic Resonance Imaging PDF Author: Zhi-Pei Liang
Publisher: Wiley-IEEE Press
ISBN:
Category : Medical
Languages : en
Pages : 442

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Book Description
In 1971 Dr. Paul C. Lauterbur pioneered spatial information encoding principles that made image formation possible by using magnetic resonance signals. Now Lauterbur, "father of the MRI", and Dr. Zhi-Pei Liang have co-authored the first engineering textbook on magnetic resonance imaging. This long-awaited, definitive text will help undergraduate and graduate students of biomedical engineering, biomedical imaging scientists, radiologists, and electrical engineers gain an in-depth understanding of MRI principles. The authors use a signal processing approach to describe the fundamentals of magnetic resonance imaging. You will find a clear and rigorous discussion of these carefully selected essential topics: Mathematical fundamentals Signal generation and detection principles Signal characteristics Signal localization principles Image reconstruction techniques Image contrast mechanisms Image resolution, noise, and artifacts Fast-scan imaging Constrained reconstruction Complete with a comprehensive set of examples and homework problems, Principles of Magnetic Resonance Imaging is the must-read book to improve your knowledge of this revolutionary technique.

Imaging Systems for Medical Diagnostics

Imaging Systems for Medical Diagnostics PDF Author: Arnulf Oppelt
Publisher: John Wiley & Sons
ISBN: 3895786691
Category : Medical
Languages : en
Pages : 996

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Book Description
The book provides a comprehensive compilation of fundamentals, technical solutions and applications for medical imaging systems. It is intended as a handbook for students in biomedical engineering, for medical physicists, and for engineers working on medical technologies, as well as for lecturers at universities and engineering schools. For qualified personnel at hospitals, and physicians working with these instruments it serves as a basic source of information. This also applies for service engineers and marketing specialists. The book starts with the representation of the physical basics of image processing, implying some knowledge of Fourier transforms. After that, experienced authors describe technical solutions and applications for imaging systems in medical diagnostics. The applications comprise the fields of X-ray diagnostics, computed tomography, nuclear medical diagnostics, magnetic resonance imaging, sonography, molecular imaging and hybrid systems. Considering the increasing importance of software based solutions, emphasis is also laid on the imaging software platform and hospital information systems.

NMR in Biomedicine

NMR in Biomedicine PDF Author: Eiichi Fukushima
Publisher: Springer Science & Business Media
ISBN: 9780883186091
Category : Science
Languages : en
Pages : 186

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Book Description
For scientists in physics, chemistry, biology, engineering, medicine, and other disciplines

Electromagnetic Analysis and Design in Magnetic Resonance Imaging

Electromagnetic Analysis and Design in Magnetic Resonance Imaging PDF Author: Jianming Jin
Publisher: Routledge
ISBN: 1351453416
Category : Medical
Languages : en
Pages : 282

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Book Description
This book presents a comprehensive treatment of electromagnetic analysis and design of three critical devices for an MRI system - the magnet, gradient coils, and radiofrequency (RF) coils. Electromagnetic Analysis and Design in Magnetic Resonance Imaging is unique in its detailed examination of the analysis and design of the hardware for an MRI system. It takes an engineering perspective to serve the many scientists and engineers in this rapidly expanding field. Chapters present: an introduction to MRI basic concepts of electromagnetics, including Helmholtz and Maxwell coils, inductance calculation, and magnetic fields produced by special cylindrical and spherical surface currents principles for the analysis and design of gradient coils, including discrete wires and the target field method analysis of RF coils based on the equivalent lumped-circuit model as well as an analysis based on the integral equation formulation survey of special purpose RF coils analytical and numerical methods for the analysis of electromagnetic fields in biological objects With the continued, active development of MRI instrumentation, Electromagnetic Analysis and Design in Magnetic Resonance Imaging presents an excellent, logically organized text - an indispensable resource for engineers, physicists, and graduate students working in the field of MRI.