The existing direction of arrival （DOA） estimation algorithms based on the electromagnetic vector sensors array barely deal with the coexisting of independent and coherent signals. A two-dimensional direction findin...The existing direction of arrival （DOA） estimation algorithms based on the electromagnetic vector sensors array barely deal with the coexisting of independent and coherent signals. A two-dimensional direction finding method using an L-shape electromagnetic vector sensors array is proposed. According to this method, the DOAs of the independent signals and the coherent signals are estimated separately, so that the array aperture can be exploited sufficiently. Firstly, the DOAs of the independent signals are estimated by the estimation of signal parameters via rotational invariance techniques, and the influence of the co- herent signals can be eliminated by utilizing the property of the coherent signals. Then the data covariance matrix containing the information of the coherent signals only is obtained by exploiting the Toeplitz property of the independent signals, and an improved polarimetric angular smoothing technique is proposed to de-correlate the coherent signals. This new method is more practical in actual signal environment than common DOA estimation algorithms and can expand the array aperture. Simulation results are presented to show the estimating performance of the proposed method.展开更多
针对传统液相免疫检测中操作复杂、步骤繁琐,检测时间长以及无法准确量化Na^(+)离子含量等问题,提出了一种利用超顺磁性磁纳米粒子与Na^(+)离子结合后其弛豫时间发生变化,进而影响磁响应信号的特性,对Na^(+)离子含量进行快速定量检测的...针对传统液相免疫检测中操作复杂、步骤繁琐,检测时间长以及无法准确量化Na^(+)离子含量等问题,提出了一种利用超顺磁性磁纳米粒子与Na^(+)离子结合后其弛豫时间发生变化,进而影响磁响应信号的特性,对Na^(+)离子含量进行快速定量检测的方法。基于磁阻传感器高灵敏度、高分辨率性能,研发设计了一套剩磁免疫检测系统,对系统性能及不同浓度Na^(+)离子结合样本剩磁信号进行检测。实验结果表明,该检测系统噪声由传感器空载时的109.38 m V降低至18.75 m V,信噪比提升了15.32 d B,检测灵敏度大幅提高,且可有效量化Na^(+)离子含量,检测误差在±9%以内。该方法磁化响应快,步骤简单,仅需2 min即可完成检测,为临床快速检测离子含量奠定了良好实验基础。展开更多
基金supported by the National Natural Science Foundation of China (61102106)the Fundamental Research Funds for the Central Universities (HEUCF1208 HEUCF100801)
文摘The existing direction of arrival （DOA） estimation algorithms based on the electromagnetic vector sensors array barely deal with the coexisting of independent and coherent signals. A two-dimensional direction finding method using an L-shape electromagnetic vector sensors array is proposed. According to this method, the DOAs of the independent signals and the coherent signals are estimated separately, so that the array aperture can be exploited sufficiently. Firstly, the DOAs of the independent signals are estimated by the estimation of signal parameters via rotational invariance techniques, and the influence of the co- herent signals can be eliminated by utilizing the property of the coherent signals. Then the data covariance matrix containing the information of the coherent signals only is obtained by exploiting the Toeplitz property of the independent signals, and an improved polarimetric angular smoothing technique is proposed to de-correlate the coherent signals. This new method is more practical in actual signal environment than common DOA estimation algorithms and can expand the array aperture. Simulation results are presented to show the estimating performance of the proposed method.
文摘针对传统液相免疫检测中操作复杂、步骤繁琐,检测时间长以及无法准确量化Na^(+)离子含量等问题,提出了一种利用超顺磁性磁纳米粒子与Na^(+)离子结合后其弛豫时间发生变化,进而影响磁响应信号的特性,对Na^(+)离子含量进行快速定量检测的方法。基于磁阻传感器高灵敏度、高分辨率性能,研发设计了一套剩磁免疫检测系统,对系统性能及不同浓度Na^(+)离子结合样本剩磁信号进行检测。实验结果表明,该检测系统噪声由传感器空载时的109.38 m V降低至18.75 m V,信噪比提升了15.32 d B,检测灵敏度大幅提高,且可有效量化Na^(+)离子含量,检测误差在±9%以内。该方法磁化响应快,步骤简单,仅需2 min即可完成检测,为临床快速检测离子含量奠定了良好实验基础。
