In this paper, an approach to the design of shielded radio-frequency （RF） phased-array coils for magnetic resonance imaging （MRI） is proposed. The target field method is used to find current densities distributed ...In this paper, an approach to the design of shielded radio-frequency （RF） phased-array coils for magnetic resonance imaging （MRI） is proposed. The target field method is used to find current densities distributed on primary and shield coils. The stream function technique is used to discretize current densities and to obtain the winding patterns of the coils. The corresponding highly ill-conditioned integral equation is solved by the Tikhonov regularization with a penalty function related to the minimum curvature. To balance the simplicity and smoothness with the homogeneity of the magnetic field of the coll＇s winding pattern, the selection of a penalty factor is discussed in detail.展开更多
In this article, a novel designed radio frequency （RF） coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging （MRI） system. Two sets of Helmholtz coil pairs with a ...In this article, a novel designed radio frequency （RF） coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging （MRI） system. Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil. The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation. The size and the shape of the new coil are optimized and validated by simulation through using the finite element method （FEM）. Good magnetic resonance （MR） images are achieved on a shepherd dog.展开更多
电子商品防盗系统(EAS)中使用的一类硬标签核心电路由磁棒线圈和电容串联组成,LC谐振频率F和品质因数Q值是硬标签关键质量参数。针对该类硬标签参数检测的市场需求和传统双线圈检测方法存在的不足,提出了一种基于互感耦合原理,以亥姆赫...电子商品防盗系统(EAS)中使用的一类硬标签核心电路由磁棒线圈和电容串联组成,LC谐振频率F和品质因数Q值是硬标签关键质量参数。针对该类硬标签参数检测的市场需求和传统双线圈检测方法存在的不足,提出了一种基于互感耦合原理,以亥姆赫兹线圈磁场为激励,采用差分和二级积分电路获取硬标签幅频特性信息的检测方法,搭建了硬标签参数检测传感器电路分析传感器检测F、Q值的理论模型。通过对市售58 k Hz硬标签试验数据的分析表明:该传感器F、Q值的绝对误差分别小于0.025 k Hz和1.3,其谐振频率测试性能明显优于市售EAS频率检测仪(E-X5006AM),性能满足行业测试要求。该传感器可为硬标签生产过程和质量检测提供F和Q值信息,具有行业实际应用价值。展开更多
无线电能传输WPT(wireless power transfer)技术作为一种新型的电能传输方式以其高可靠性、实用性和安全性而备受关注。然而WPT能否替代传统的有线输电而成为通用技术,其最关键的影响因素之一就是传输效率。首先,针对WPT技术对于传输效...无线电能传输WPT(wireless power transfer)技术作为一种新型的电能传输方式以其高可靠性、实用性和安全性而备受关注。然而WPT能否替代传统的有线输电而成为通用技术,其最关键的影响因素之一就是传输效率。首先,针对WPT技术对于传输效率优化的迫切需求,系统综述了国内外在磁耦合谐振式WPT研究领域中关于传输效率优化方法的研究进展。然后,对WPT系统的研究进展进行了综述,分别从线圈优化设计、谐振链路改进、频率控制及阻抗调节4个方面,介绍了近年来国内外关于磁耦合谐振式WPT传输效率优化方法的研究进展。最后,对WPT技术传输效率优化研究的未来发展趋势进行了展望。展开更多
基金Project supported by the National Nature Science Foundation of China (Grant No. 30900332)Grant of General Administration of Quality Supervision Inspection and Quarantine of China (Grant No. 201210079)+1 种基金the Program for Science and Technology Department of Zhejiang Province, China (Grant Nos. 2010C14010 and 2010C33172)the Natural Science Foundation of Zhejiang Province, China (Grant No. Y2090966)
文摘In this paper, an approach to the design of shielded radio-frequency （RF） phased-array coils for magnetic resonance imaging （MRI） is proposed. The target field method is used to find current densities distributed on primary and shield coils. The stream function technique is used to discretize current densities and to obtain the winding patterns of the coils. The corresponding highly ill-conditioned integral equation is solved by the Tikhonov regularization with a penalty function related to the minimum curvature. To balance the simplicity and smoothness with the homogeneity of the magnetic field of the coll＇s winding pattern, the selection of a penalty factor is discussed in detail.
基金supported by the National Key Technology Research and Development Program of China (Grant No. 001BA210A03)
文摘In this article, a novel designed radio frequency （RF） coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging （MRI） system. Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil. The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation. The size and the shape of the new coil are optimized and validated by simulation through using the finite element method （FEM）. Good magnetic resonance （MR） images are achieved on a shepherd dog.
文摘电子商品防盗系统(EAS)中使用的一类硬标签核心电路由磁棒线圈和电容串联组成,LC谐振频率F和品质因数Q值是硬标签关键质量参数。针对该类硬标签参数检测的市场需求和传统双线圈检测方法存在的不足,提出了一种基于互感耦合原理,以亥姆赫兹线圈磁场为激励,采用差分和二级积分电路获取硬标签幅频特性信息的检测方法,搭建了硬标签参数检测传感器电路分析传感器检测F、Q值的理论模型。通过对市售58 k Hz硬标签试验数据的分析表明:该传感器F、Q值的绝对误差分别小于0.025 k Hz和1.3,其谐振频率测试性能明显优于市售EAS频率检测仪(E-X5006AM),性能满足行业测试要求。该传感器可为硬标签生产过程和质量检测提供F和Q值信息,具有行业实际应用价值。
文摘无线电能传输WPT(wireless power transfer)技术作为一种新型的电能传输方式以其高可靠性、实用性和安全性而备受关注。然而WPT能否替代传统的有线输电而成为通用技术,其最关键的影响因素之一就是传输效率。首先,针对WPT技术对于传输效率优化的迫切需求,系统综述了国内外在磁耦合谐振式WPT研究领域中关于传输效率优化方法的研究进展。然后,对WPT系统的研究进展进行了综述,分别从线圈优化设计、谐振链路改进、频率控制及阻抗调节4个方面,介绍了近年来国内外关于磁耦合谐振式WPT传输效率优化方法的研究进展。最后,对WPT技术传输效率优化研究的未来发展趋势进行了展望。
