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Related papers: Parallel transmit PUlse design for Saturation Homo…

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Purpose: To employ optimal control for the numerical design of CEST saturation pulses to maximize contrast and stability against $B_0$ inhomogeneities. Theory and Methods: We applied an optimal control framework for the design pulse shapes…

Background: Magnetization transfer (MT) saturation reflects the additional saturation of the MRI signal imposed by an MT pulse and is largely driven by the saturation of the bound pool. This reduction of the bound polarization by the MT…

Medical Physics · Physics 2021-05-03 Gunther Helms , Nikolaus Weiskopf , Antoine Lutti

Purpose: Universal Pulses (UPs) are excitation pulses that reduce the flip angle inhomogeneity in high field MRI systems without subject-specific optimization, originally developed for parallel transmit (PTX) systems at 7T. We investigated…

A magnitude-least-squares radiofrequency pulse design algorithm is reported which uses interleaved exact and stochastically-generated inexact updates to escape local minima and find low-cost solutions. Inexact updates are performed using a…

Medical Physics · Physics 2024-07-23 Jonathan B. Martin , Charlotte R. Sappo , Benjamin M. Hardy , William A. Grissom

Purpose: Phosphorus saturation-transfer experiments can quantify metabolic fluxes non-invasively. Typically, the forward flux through the creatine-kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after…

The radiofrequency (RF) transmit field is severely inhomogeneous at ultrahigh field due to both RF penetration and RF coil design issues. This particularly impairs image quality for sequences that use inversion pulses such as magnetization…

Computational Engineering, Finance, and Science · Computer Science 2010-07-05 Aaron C Hurley , Ali Al-Radaideh , Bai Li , Uwe Aickelin , Ron Coxon , Paul Glover , Penny A. Gowland

We optimised the magnetic field homogeneity of two canonical designs for mobile microfluidic NMR applications: two parallel magnets with an air gap and a modified Halbach array. Along with the influence of the sample length, general design…

Applied Physics · Physics 2021-03-26 Yannick Klein , Leon Abelmann , Han Gardeniers

Purpose: Rapid 2D RF pulse design with subject specific $B_1^+$ inhomogeneity and $B_0$ off-resonance compensation at 7 T predicted from convolutional neural networks is presented. Methods: The convolution neural network was trained on half…

Affine frequency division multiplexing (AFDM) has recently emerged as a promising waveform for doubly-selective channles [1],[2], owing to its ability to fully exploit time-frequency diversity through appropriate tuning of the chirp-rate…

Signal Processing · Electrical Eng. & Systems 2026-05-19 Haojian Zhang , Jiayan Yang , Tingting Zhang , Xu Zhu , Qinyu Zhang

This paper presents numerical simulations of dual-frequency second-order ultrasound field (SURF) reverberation suppression transmit-pulse complexes. Such propagation was previously studied in a homogeneous medium. Here instead the…

Medical Physics · Physics 2013-04-16 Sven Peter Nasholm , Bjørn A. J. Angelsen

There has been an explosion of interest in time-varying photonics due to the recent discovery and design of materials and metamaterials with strong, time-varying, nonlinear optical responses. This opens the door to novel optical phenomena…

Optics · Physics 2023-07-05 Joshua Baxter , Lora Ramunno

Transcranial magnetic stimulation (TMS) with asymmetric electric field pulses, such as monophasic, offers directional selectivity for neural activation but requires excessive energy. Previous pulse shape optimisation has been limited to…

The writing energy for reversing the magnetization of the free layer in a magnetic tunnel junction (MTJ) is a key figure of merit for comparing the performances of magnetic random access memories with competing technologies. Magnetization…

This letter proposes a targeted-subharmonic-eliminating pulse density modulation (TSE-PDM) method for SS- compensated WPT systems. By designing a noise transfer function with notch characteristics, the subharmonic components which excite…

Systems and Control · Electrical Eng. & Systems 2025-09-03 Songyan Li , Hongchang Li

Ultrahigh field (UHF) Magnetic Resonance Imaging (MRI) provides a higher signal-to-noise ratio and, thereby, higher spatial resolution. However, UHF MRI introduces challenges such as transmit radiofrequency (RF) field (B1+) inhomogeneities,…

Computer Vision and Pattern Recognition · Computer Science 2025-02-07 Zhengyi Lu , Hao Liang , Xiao Wang , Xinqiang Yan , Yuankai Huo

Focusing metasurfaces (MTSs) tailored for different power allocations in wireless power transfer (WPT) system are proposed in this letter. The designed metasurface unit cells ensure that the phase shift can cover over a 2{\pi} span with…

Signal Processing · Electrical Eng. & Systems 2025-05-13 Andi Ding , Yee Hui Lee , Eng Leong Tan , Yufei Zhao , Yanqiu Jia , Yong Liang Guan , Theng Huat Gan , Cedric W. L. Lee

We propose a signal acquisition and modeling framework for multi-component tissue quantification that encompasses transmit field inhomogeneity, multi-component relaxation and magnetization transfer (MT) effects. By applying off-resonance…

Medical Physics · Physics 2025-10-08 Albert Jang , Hyungseok Jang , Nian Wang , Alexey Samsonov , Fang Liu

Bulk high-temperature superconductors (HTS) are capable of generating very strong magnetic fields while maintaining a relatively compact form factor. Solenoids constructed using stacks of ring-shaped bulk HTS have been demonstrated to be…

Applied Physics · Physics 2024-02-16 Dian Weerakonda , Benjamin Bryant , Anthony Dennis , Tobia Nava , John Durrell

Harnessing parity-time (PT) symmetry with balanced gain and loss profiles has created a variety of opportunities in electronics from wireless energy transfer to telemetry sensing and topological defect engineering. However, existing…

Applied Physics · Physics 2022-07-26 Weidong Cao , Changqing Wang , Weijian Chen , Song Hu , Hua Wang , Lan Yang , Xuan Zhang

This letter proposes a targeted-subharmonic-eliminating pulse density modulation (PDM) method for series-series (SS) compensated wireless power transfer (WPT) systems. The subharmonic frequency components which excite current abnormal…

Systems and Control · Electrical Eng. & Systems 2025-12-01 Songyan Li , Hongchang Li , Haiyue Jiang , Yudong Zhang , Wenjie Chen , Xu Yang
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