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基于贝叶斯压缩感知的毫米波MIMO信道估计 被引量:1
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作者 彭一文 任文平 钱蓉蓉 《计算机仿真》 北大核心 2020年第4期151-154,334,共5页
针对毫米波大规模多输入多输出(MIMO)通信系统中存在的硬件成本高、能耗大等问题,混合模拟-数字的收发机架构是一个很有前景的解决方案,然而系统的信道估计问题却成为一个挑战。在考虑正交频分复用和频率选择性衰落信道模型的前提下,提... 针对毫米波大规模多输入多输出(MIMO)通信系统中存在的硬件成本高、能耗大等问题,混合模拟-数字的收发机架构是一个很有前景的解决方案,然而系统的信道估计问题却成为一个挑战。在考虑正交频分复用和频率选择性衰落信道模型的前提下,提出了一种使用贝叶斯压缩感知理论来估计信道的方法。贝叶斯压缩感知算法可以在稀疏信道先验知识不完备的情况下,实现更高精度的信道估计。仿真结果验证了所提方法的有效性,与正交匹配追踪算法相比,在信噪比为30dB时,归一化均方误差降低了约25dB。 展开更多
关键词 毫米波 大规模多输入多输出 正交频分复用 贝叶斯压缩感知
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Structure optimization and flow field simulation of plate type high speed on-off valve 被引量:7
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作者 WANG Xiao-jing LI Wen-jie +1 位作者 LI Chun-hui peng yi-wen 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第5期1557-1571,共15页
There is a relatively complex flow state inside the high speed on-off valve,which often produces low pressure area and oil reflux in the high-speed opening and closing process of the spool,causing cavitation and vorte... There is a relatively complex flow state inside the high speed on-off valve,which often produces low pressure area and oil reflux in the high-speed opening and closing process of the spool,causing cavitation and vortex and other phenomena.These phenomena will affect the stability of the internal flow field of the plate valve and the flow characteristics of the high speed on-off valve.Aiming at the problems of small flow rate and instability of internal flow field,a new spool structure was designed.The flow field models of two-hole and three-hole plate spools with different openings were established,and software ANSYS Workbench was chosen to mesh the model.The standard k−εturbulence model was selected for numerical simulation using FLUENT software.The pressure distribution and velocity distribution under the same pressure and different opening degree were obtained.The structure and parameters of the optimization model were also obtained.The stability analysis of flow field under different pressure was carried out.The results demonstrate that the three-hole spool has a similar flow field change with the two-hole spool,but it does not create a low pressure zone,and the three-hole spool can work stably at 2 MPa or less.This method improves the appearance of low pressure area and oil backflow in the process of high speed opening and closing of spool.The stability of flow field and the flow rate of high speed switch valve are improved.Finally,the products designed in this paper are compared with existing hydraulic valve products.The results show that the three-hole plate type high speed on-off valve designed in this paper maintains the stability of the internal flow field under the condition of 200 Hz and large opening degree,and realizes the increase of flow rate. 展开更多
关键词 high speed on-off valve flow field simulation pressure and flow characteristics
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盘州市薏苡绿色增产增效栽培技术 被引量:4
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作者 彭泽信 彭益稳 章洁琼 《耕作与栽培》 2018年第3期57-59,共3页
根据近年来薏苡栽培技术试验示范成果及生产实践,总结出适宜盘州市的薏苡绿色增产增效栽培技术,为薏苡大规模的绿色生产提供了技术支撑,进一步推动薏苡产业的健康发展。
关键词 盘州市 薏苡 绿色 增产增效 栽培技术
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