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The common two dimensional (2-D) direction of arrival (DOA) estimation algorithms for coexisting uncorrelated and coherent signals are based on the complex array structure, such as the uniform rectangular array, so the computational complexity is high and the array aperture is not utilized efficiently. By taking advantage of the L-shape array and adopting an efficient method to eliminate the Gaussian noise, a new 2-D DOA estimation method is proposed. Firstly, the DOAs of the uncorrelated signals are estimated and the influence of the coherent signals is eliminated by utilizing its characteristics. Then, the data covariance matrix containing the coherent information only is obtained by exploiting the Toeplitz property of the uncorrelated signals, and the DOAs of the coherent signals are estimated by the direction finding method based on the compressed sensing theory. Theoretical analysis and simulation results show that the proposed method has a small computational load, high array aperture as well as excellent estimation performance. 相似文献
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为降低多高层钢结构的梁柱间的装配难度,提出了法兰连接L形钢管混凝土柱-H型钢梁全螺栓装配节点,包括梁与柱连接和柱与柱连接,梁与柱现场全螺栓连接,柱与柱现场法兰连接。为研究连接件形式及加劲肋对该种节点抗震性能的影响,以改变连接件形式、加劲构造为主要变化参数,设计了4个该类型节点,通过低周反复加载试验和有限元分析获得了节点的破坏模式、滞回曲线、耗能能力和性能指标。研究结果表明:4个节点的滞回曲线均呈梭形,具有良好的耗能能力;节点正负方向的塑性转角超过0.05 rad,满足抗震规范要求;L形连接件与T形连接件均有足够的刚度传递荷载,4个节点的破坏模式、耗能能力与滞回曲线形状较为接近;连接件与梁翼缘之间的滑移提高了节点的延性、耗能能力与转动能力。 相似文献
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针对L形截面柱在双向弯矩鸭,幔作用下发生的双向纯弯曲耦合问题采用逆解法和应力函数方程进行了求解,并且得出I形截面柱发生双向纯弯曲耦合现象的主要原因是截面的Iye≠0的结论。 相似文献
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L型平面不规则结构抗震设计分析 总被引:2,自引:0,他引:2
运用SATWE和GSSAP程序,对某L型平面不规则结构进行了详细的抗震设计分析,列出了多项结构指标的对比结果,并提出了相应的抗震加强措施,为同类超限高层结构设计提供参考. 相似文献
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A new method is presented to estimate two-dimensional (2-D) Direction-of-Arrival (DOA) angles of narrowband real-valued signals impinging on a L-shape Arrays(LA). The basic idea of the proposed method is to increase both the effective aperture size and the number of sensors by employing the conjugate invariance property of real-valued signals. Thus, the proposed method can provide a more precise DOA and detect more signals than the Cross-Correlation Matrix Method (CCMM). Numerical simulation results are presented to support the theory. 相似文献
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针对卫星移动通信系统,文中设计了一种新型圆极化微带天线。通过使用四臂“L”形探针、寄生层叠结构和带状线馈电网络实现了宽带、宽波束和双圆极化工作。对原理样机进行测试,结果表明,天线在20%的工作带宽内电压驻波比<2.0∶[KG-2mm]1,轴比<3.2 dB,3 dB波束宽度>120°。 相似文献
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K. S. Lee 《The International Journal of Advanced Manufacturing Technology》2006,30(7-8):677-686
This study examined the finite element and abductive network method applied to thegas-assisted injection mould (GAIM). From these models, the effect of the GAIM condition includes the melt formation by percent volume filled, the base-plane thickness, and the ratio of L-shape plane thickness. The L-shape plane can reduce by about 50 per cent the expense of materials, reduce the injection cycle time, and increase the L-shape structure. In order to select the optimal design parameters to minimize the warp of a GAIM, the experimental design method and abductive network were used. These methods were applied to create an efficient model with functional nodes. Once the GAIM parameters were developed, this network was used to predict GAIM warp accurately. A simulated annealing (SA) optimization algorithm with a performance index was then applied to the neural network for searching the optimal GAIM parameters, obtaining a more satisfactory result compared to the corresponding finite element verification. 相似文献