Author: Yoseph Shiferaw
Publisher:
ISBN:
Category :
Languages : en
Pages : 174

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Author: B. J. Fisher
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Chih-Wei Chang
Publisher:
ISBN:
Category : Electric coils
Languages : en
Pages : 140

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Author: Qingxin Yang
Publisher: Springer Nature
ISBN: 9819934044
Category : Technology & Engineering
Languages : en
Pages : 1290

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Book Description
This book includes the original, peer-reviewed research papers from the 10th Frontier Academic Forum of Electrical Engineering (FAFEE 2022), held in Xi’an, China, in August 2022. It gathers the latest research, innovations, and applications in the fields of Electrical Engineering. The topics it covers include electrical materials and equipment, electrical energy storage and device, power electronics and drives, new energy electric power system equipment, IntelliSense and intelligent equipment, biological electromagnetism and its applications, and insulation and discharge computation for power equipment. Given its scope, the book benefits all researchers, engineers, and graduate students who want to learn about cutting-edge advances in Electrical Engineering.

Author: Qiuliang Wang
Publisher: John Wiley & Sons
ISBN: 1118398173
Category : Science
Languages : en
Pages : 484

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Book Description
Magnets are widely used in industry, medical, scientific instruments, and electrical equipment. They are the basic tools for scientific research and electromagnetic devices. Numerical methods for the magnetic field analysis combined with mathematical optimization from practical applications of the magnets have been widely studied in recent years. It is necessary for professional researchers, engineers, and students to study these numerical methods for the complex magnet structure design instead of using traditional "trial-and-error" methods. Those working in this field will find this book useful as a reference to help reduce costs and obtain good magnetic field quality. Presents a clear introduction to magnet technology, followed by basic theories, numerical analysis, and practical applications Emphasizes the latest developments in magnet design, including MRI systems Provides comprehensive numerical techniques that provide solutions to practical problems Introduces the latest computation techniques for optimizing and characterizing the magnetostatic structure design Well organized and adaptable by researchers, engineers, lecturers, and students Appendix available on the Wiley Companion Website As a comprehensive treatment of the topic, Practical Design of Magnetostatic Structure Using Numerical Simulation is ideal for researchers in the field of magnets and their applications, materials scientists, structural engineers, and graduate students in electrical engineering. The book will also better equip mechanical engineers and aerospace engineers.

Author: Pierre-Marie Robitaille
Publisher: Springer Science & Business Media
ISBN: 0387496483
Category : Medical
Languages : en
Pages : 487

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Book Description
The foundation for understanding the function and dynamics of biological systems is not only knowledge of their structure, but the new methodologies and applications used to determine that structure. This volume in Biological Magnetic Resonance emphasizes the methods that involve Ultra High Field Magnetic Resonance Imaging. It will interest researchers working in the field of imaging.

Author: Jianming Jin
Publisher: Routledge
ISBN: 1351453408
Category : Medical
Languages : en
Pages : 304

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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.

Author: Gerrit Schultz
Publisher: Springer Science & Business Media
ISBN: 3658011343
Category : Technology & Engineering
Languages : en
Pages : 343

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Book Description
​Within the past few decades MRI has become one of the most important imaging modalities in medicine. For a reliable diagnosis of pathologies further technological improvements are of primary importance. This study deals with a radically new approach of image encoding. Gradient linearity has ever since been an unquestioned technological design criterion. With the advent of parallel imaging, this approach may be questioned, making way of much a more flexible gradient hardware that uses encoding fields with an arbitrary geometry. The theoretical basis of this new imaging modality – PatLoc imaging – are comprehensively presented, suitable image reconstruction algorithms are developed for a variety of imaging sequences and imaging results – including in vivo data – are explored based on novel hardware designs.

Author: Chad Tyler Harris
Publisher:
ISBN:
Category :
Languages : en
Pages : 502

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Book Description
Magnetic resonance imaging (MRI) has proven to be a valuable methodological approach in both basic research and clinical practice. However, significant hardware advances are still needed in order to further improve and extend the applications of the technique. The present dissertation predominantly addresses gradient and shim coil design (sub-systems of the MR system). A design study to investigate gradient performance over a set of surface geometries ranging in curvature from planar to a full cylinder using the boundary element (BE) method is presented. The results of this study serve as a guide for future planar and pseudo-planar gradient systems for a range of applications. Additions to the BE method of coil design are developed, including the direct control of the magnetic field uniformity produced by the final electromagnet and the minimum separation between adjacent wires in the final design. A method to simulate induced eddy currents on thin conducting surfaces is presented. The method is used to predict the time-dependent decay of eddy currents induced on a cylindrical copper bore within a 7 T MR system and the induced heating on small conducting structures; both predictions are compared against experiment. Next, the method is extended to predict localized power deposition and the spatial distribution of force due to the Lorentz interaction of the eddy current distribution with the main magnetic field. New methods for the design of actively shielded electromagnets are presented and compared with existing techniques for the case of a whole-body transverse gradient coil. The methods are judged using a variety of shielding performance parameters. A novel approach to eliminate the interactions between the MR gradient system and external, non-MR specific, active devices is presented and its feasibility is discussed. A completely new approach to shimming is presented utilizing a network of current pathways that can be adaptively changed on a subject-by-subject basis and dynamically controlled. The potential benefits of the approach are demonstrated using computer simulations and a prototype coil is constructed and tested as a proof-of-principle.

Author: Stefan Kroboth
Publisher:
ISBN:
Category : Magnetic resonance imaging
Languages : en
Pages :

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Book Description
Abstract: Magnetic Resonance Imaging (MRI) is a tomographic imaging modality commonly used for diagnosis in medicine. In an attempt to push the limits of MRI, quadratic magnetic fields were recently added to the image encoding process. While this concept was shown to aid the image acquisition, it is yet unclear, which properties such nonlinear fields should have in order to fully exploit their potential. Therefore in the recent past so-called matrix gradient coils, which consist of a large number of small coils, were introduced. The current in each such coil element can be adjusted individually, and the final field shape is given by the superposition of the fields of all coil elements. Such an approach on one hand allows for a wide range of different field shapes. On the other hand it necessitates as many amplifiers as coil elements, which can be expensive and technically challenging. The first part of this thesis introduces a method for overcoming the above-mentioned problem by driving the matrix gradient coil with fewer amplifiers than coil elements. This is achieved by first finding a so-called configuration, which defines a network of coils capable of approximating a desired field shape. Since most image encoding strategies in MRI require more than a single field, one configuration per target field is obtained. Then a switching circuit is optimized, which is able to switch between the set of configurations with a low number of switches. While nonlinear fields have shown to add additional degrees of freedom to the image acquisition process, it remained unclear how to utilize them for image encoding in MRI most efficiently. Therefore the second part this thesis introduces an algorithm, which obtains ways to drive the acquisition of the MR signal by efficiently utilizing the available hardware (gradient coils with arbitrary field geometries, radio-frequency receiver coils) such that the overall acquired information content is maximized. This approach can also be used as a means to investigate the interplay of spatial encoding steps and local radio-frequency receiver coils, which may help to find ways of driving the available hardware, such that imperfections of one component are compensated for by another component while reducing the number of required encoding steps. In the past, hardware components where typically designed independent of each other, but with the insights gained from this method, it may in the future be possible to design components in parallel while considering their interactions with each other. This may in the future lead to faster and higher quality image acquisition, which is beneficial for both the operation of the MRI as well as the patients