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基于Geant4蒙特卡罗软件包对比不同空腔模型下水模体中剂量分布与无空腔时的差异,探讨空腔对补偿膜下剂量的影响.以Geant4构建加速器机头模型并获取机头下相空间文件,构建上表面位于源轴距、中心在射野中心并与射野中心轴垂直的30 cm×30 cm×30 cm水模体,在近机头一侧分别构建不含或含有不同厚度空腔的0.3 c... 相似文献
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文章报告了2020-2021年如东县配合饲料养蚕情况,2020-2021年推广稚蚕配合饲料共育553张;新建设饲料养蚕示范基地3个,首次在农户现有生产条件建设批量养蚕超过20张的饲料养蚕示范基地;在全县3个饲料养蚕示范基地示范配合饲料全龄养蚕206.0张,产茧4 259.35kg,平均张种产茧20.68kg;初步解决了扩座、上蔟营茧以及采茧等环节适合规模化养殖生产的技术瓶颈;家蚕低成本配合饲料产业化生产工艺日趋成熟,家蚕配合饲料成本进一步降低,达到了配合饲料全龄养蚕技术良性循环的目标;开展了原蚕配合饲料全龄养蚕技术探索;用配合饲料养蚕所产蚕茧加工的丝绵,其压缩回弹性能良好。 相似文献
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可重构智能超表面(RIS)是一种新型人工电磁材料,可灵活调控电磁波的频率、幅度、相位、极化、传播方向、波形等特性。在无线通信领域,可利用RIS重构无线通信信道,实现无线信号的盲区覆盖,提高通信质量。首先,概述了RIS技术的发展和研究现状,分析了RIS的关键技术和应用场景。然后,提出了一种新型无源RIS,通过无源编码和拼接原理实现了RIS口径可重构和波束可重构特性,具有低成本、低功耗、低复杂度的优点。最后,在实际室内环境下进行了基于无源RIS的室内无线信号盲区覆盖增强实验。通过仿真与实测对比,证明了无源可拼接超表面在无线通信补盲场景应用中的有效性。此外,针对5G/6G毫米波通信,设计了双层十字交叉振子无源RIS,应用到室内典型的L形走廊场景,验证了无源RIS对室内无线信号覆盖的增强效果。 相似文献
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The electromagnetic vortex wave has demonstrated excellent research value with potential applications in the fields of wireless communication and radar detection and imaging due to its unusual electromagnetic field distribution and theoretically infinite orthogonal Orbital Angular Momentum (OAM) modes. This study analyzes the anti-interference performance of OAM modes in the electromagnetic vortex Radio Frequency (RF) transceiver link primarily from the perspective of the electromagnetic vortex field distributions in space and the OAM modes orthogonality. Planar antenna arrays are designed to generate the electromagnetic vortex beams with respective OAM modes of and in the C band, and the corresponding RF transceiver links are established. The OAM modes’ anti-interference properties under different interference situations are analyzed in the electromagnetic vortex RF transceiver link by using a horn antenna as the interference source. Meanwhile, the corresponding OAM mode spectrum and the OAM modes’ orthogonality are employed as the primary methods in our analysis. Finally, the designed antenna models are fabricated, and the electromagnetic vortex RF transceiver links are measured. The corresponding analyses and conclusions are presented in this study. The OAM modes’ anti-interference performance analysis in the vortex electromagnetic wave’s RF transceiver link can provide a reference for exploring and designing a vortex electromagnetic wave in wireless communication and radar detection and imaging research. 相似文献
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