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为进一步提升毫米波折叠波导行波管的输出功率,通过整体加工的工艺方法,将折叠波导慢波结构和周期永磁聚焦系统在母材上同时加工,形成一种集成极靴结构。基于圆形注电子光学系统,设计了E波段折叠波导行波管的集成极靴结构。利用三维电磁场模拟软件(CST)的微波工作室,设计并模拟了慢波结构的冷特性参数,并根据慢波结构尺寸设计周期永磁聚焦系统。通过电磁工作环境仿真软件(OPERA)对磁场进行仿真验证,最终整管粒子数值模拟(PIC)计算结果表明,在61~71 GHz频带内可获得大于1 kW的饱和输出功率。该集成极靴结构在提供强轴向磁场的同时,具有结构紧凑、散热性好等优点。 相似文献
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毫米波耦合腔行波管非旋转轴对称PPM聚焦系统中的横向磁场 总被引:6,自引:3,他引:3
本文对一种能适应低电压大功率应用需要的毫米波耦合腔行波管的复合型PPM聚焦系统进行了分析,研究了系统中旋转轴对称性引起的横向磁场,探讨了极靴饱和以及加工和装配误差对聚焦系统的影响,并给出了有关的计算公式。 相似文献
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《电子材料与电子技术》2005,32(3):31
磁性复合材料主要分为永磁复合材料和软磁复合材料两大类。稀土永磁材料是最早发展起来的永磁材料,一直占据主流地位。它是稀土元素和过渡族金属形成的一类高性能永磁材料,其性能特征是磁化强度高,剩余磁感应强度高,矫顽力性能较好,且是目前种类最多和应用最广的磁性材料。这类材料径历了SmC05、Sm2Co17、Nd2Fe14 B等3个发展阶段,目前Nd—Fe—B永磁材料以其高性能、轻型和微型的特征独占鳌头。目前有报道称可以得到磁能积达558.4kJ/m^3的烧结NdFeB永磁体,但其加工性能较差。 相似文献
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集成极靴式互作用系统在高频段行波管中有着巨大的应用潜力,而在其设计和应用过程中,最大限度地克服横
向磁场是一个十分重要的问题。介绍了集成极靴式互作用系统的结构单元、工作原理和比较优势;基于一段特定几何尺
寸的集成极靴式互作用系统,先定性分析了影响其磁场分布的关键参量,然后利用CST 静磁工作室详细研究了各个参量
的变化与其磁场分布的相互关系。计算结果不仅可以进一步加深对矩形磁钢磁场分布的认识,也为集成极靴式互作用系
统的在高频段行波管中的应用奠定了基础。 相似文献
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设计了Hybrid结构的周期永磁聚束系统,该结构不仅轴向磁感应强度很高,而且体系外的漏磁很弱。内径为15mm,外径为40 mm,周期为40 mm,径向磁环和轴向磁环厚度之比为1∶1的Hybrid-PPM结构,轴线上磁感应强度的峰值达到0.5 T,体系外漏磁小于0.06 T。对影响Hybrid结构的PPM磁场峰值分布的因素进行了分析,磁场分布的峰值随内径增大迅速下降;外径增大对峰值的影响不显著,当外径增加至与体系的周期相当时,峰值几乎不变;体系的峰值随周期长度的增加迅速增大;体系的峰值与周期内径向磁环与轴向磁环厚度的比值有关,周期一定时,存在一个最佳的比值点,磁场的峰值达到最大。 相似文献
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《电子技术与软件工程》2017,(15)
在永磁材料推广应用的过程中,其性能使用程度的提升成为了当前关注的焦点。另外,永磁材料在特殊材质下产生的磁场效应,也是行业研究的重点内容。只有事前充分模拟永磁材料的磁特性,后期实际的磁体结构所产生的真实磁场与计算出磁场的误差才会尽可能的降低,这样才能设计出符合实际生产所需的永磁体。本文基于强磁场下永磁材料磁滞特性的数值模拟有关问题研究,希望能够最大程度上克服传统简化模拟方法在强磁场永磁体数值计算中出现的误差问题,提升精准度,有效指导实践工作。 相似文献
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厚膜永磁阵列是近年来 MEMS器件中的重要材料之一 ,研究其表面磁场分布对实际应用中永磁阵列单元几何尺寸的设计具有重要指导作用。文中建立了厚膜永磁阵列表面磁场分布的计算模型 ,并得到了永磁阵列表面磁场分布。结果表明永磁阵列表面磁场呈周期性分布 ,与磁体单元高度、宽度以及磁体单元间隔密切相关。 相似文献
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Ya Li Zhijie Qi Jingxuan Yang Mingxing Zhou Xin Zhang Wei Ling Yingying Zhang Ziyue Wu Hanjie Wang Baoan Ning Hang Xu Wenxing Huo Xian Huang 《Advanced functional materials》2019,29(44)
Permanent magnets are essential components for many biomedical systems and electromechanical devices, which may be made into flexible formats to achieve wearable monitoring and effective integration with biological tissues. However, the development of high‐performance flexible permanent magnets is challenging due to their ultrathin geometries, which contradict with the thickness‐dependent magnetic properties. In addition, magnetic membranes with controllable sequences of polarities are difficult to achieve. Here, origami techniques to achieve flexible permanent magnetic membranes with enhanced magnetic field strength and programmable sequences of polarities are presented. Linear Halbach arrays, circular Halbach arrays, and concentric magnets with thicknesses ranging from 130 to 500 µm and bending curvatures ranging from 0.039 to 0.0043 µm?1 are achieved through different folding mechanisms. The origami membranes offer a maximum field intensity of 72 mT and extremely strong magnetic force of 0.21 N cm?2, allowing various novel applications demonstrated through electronics interfacing, cell manipulations, and soft robotics. The origami techniques offer large magnetism and complex spatial field distribution, and enable practical use of thin flexible magnetic membranes in constructing miniaturized or even flexible electromechanical systems and biomedical instruments for magnetic resonance imaging, targeted drug delivery, health monitoring, and cancer therapy. 相似文献
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Jeotikanta Mohapatra Meiying Xing Jacob Elkins Julian Beatty J. Ping Liu 《Advanced functional materials》2021,31(13):2010157
Brown's theorem on coercivity of ferromagnetic materials has predicted that the coercivity level is substantially higher than in practice for all the materials studied in experiments in the past seven decades, which is known as the Brown's paradox. In this paper, a system with a coercivity close to the one predicted by Brown's theorem is investigated. Cobalt nanowires are obtained by chemical synthesis that give rise to coercive forces significantly higher than the magnetocrystalline anisotropy field, verifying the Brown's theorem. It is found that the coercivity is strongly dependent on the nanowire diameter, the alignment of the wires in an assembly, and the packing density of the assembly. An analysis based on the current experimental results and related literature reveals a coercivity ceiling in consideration of geometrical dimensions and the effective magnetic anisotropy. Quantitative information is obtained about the proximity effect on the coercivity and the magnetization which shows the correlation between the energy product and the packing density. Furthermore, it is found that by coating the nanowires with Fe, the energy density can be enhanced. These findings provide a guideline for materials design of future high-performance permanent magnets that take advantage of shape anisotropy at the nanoscale. 相似文献
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Heng-An Zhou Jiahao Liu Zidong Wang Qihan Zhang Teng Xu Yiqing Dong Le Zhao Soong-Geun Je Mi-Young Im Kun Xu Jing Zhu Wanjun Jiang 《Advanced functional materials》2021,31(46):2104426
Interfacially asymmetric magnetic multilayers made of heavy metal/ferromagnet have attracted considerable attention in the spintronics community for accommodating spin-orbit torques (SOTs) and meanwhile for hosting chiral spin textures. In these multilayers, the accompanied interfacial Dzyaloshinskii–Moriya interaction (iDMI) permits the formation of Néel-type spin textures. While significant progresses have been made in Co, CoFeB, Co2FeAl, CoFeGd based multilayers, it would be intriguing to identify new magnetic multilayers that could enable spin-torque controllability and meanwhile host nanoscale skyrmions. In this report, first, thin films made of permanent magnet SmCo5 with perpendicular magnetic anisotropy are synthesized, in which the deterministic SOT switching, enabled by the spin Hall effect, in Pt/SmCo5/Ta trilayer is demonstrated. Further, the stabilization of room-temperature skyrmions with diameters ≈100 nm in [Pt/SmCo5/Ta]15, together with a skyrmionium-like spin texture in [Pt/SmCo5/Ir]15 multilayers is shown. Based on the material specific parameters, micromagnetic simulations are also carried out. The results confirm the presence of chiral spin textures in this new material family. Through interfacial engineering, the results thus demonstrate that rare earth permanent magnets could be a new platform for studying interfacial chiral spintronics. 相似文献
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钕铁硼永磁材料的性能及研究进展 总被引:5,自引:0,他引:5
钕铁硼磁体被称为第3代稀土永磁材料,烧结钕铁硼磁体是目前综合磁性能最高的永磁材料。概述了钕铁硼永磁材料的研究进展和应用领域,介绍了钕铁硼磁体的性能及先进制备工艺,指出了目前国内钕铁硼磁体存在的主要问题及今后的研究方向。 相似文献
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本文设计了一种可调的叠式钐钴永磁迥路。用三层径向磁化的钐钴磁体和软铁类磁导材料,借助于计算机,设计了沿轴向长2.0mm,磁场强度1.2kGs,波动±0.7%的均匀磁场,为高功率微波管的永磁聚焦系统提供了一种优良的永磁迴路。 相似文献