In the signal processing for metrewave radar, the reflection paths of target echoes can cause severe error in the elevation estimation for the low-angle target tracking. The exact angles of the reflection paths are un...In the signal processing for metrewave radar, the reflection paths of target echoes can cause severe error in the elevation estimation for the low-angle target tracking. The exact angles of the reflection paths are unknown beforehand, and therefore, the reflection paths can not be suppressed easily. Therefore, in this article, an improved reflection paths suppression approach is presented. A block matrix aggregate is constructed based on the possible angles of the reflection paths. Combined with the beamforming-like processing, a generalized maximum likelihood estimation is derived to optimize the estimation. Moreover, the noise reduction method based on the Toeplitz covariance matrix is used for better performance. This approach is applied to the real data collected by the low-angle tracking radar with 8-channel vertical array. The experiment results show that the reflection effects are reduced and the accuracy of the elevation estimate is improved.展开更多
Based on Chen-Haus ' theory~[1] , an experimental research on the reflection of SAW from a short-circuited Au -grating on YZ LiNbO3 and a short-circuited Al- recessed groove grating on ST-X quartz is first present...Based on Chen-Haus ' theory~[1] , an experimental research on the reflection of SAW from a short-circuited Au -grating on YZ LiNbO3 and a short-circuited Al- recessed groove grating on ST-X quartz is first presented in this paper where an anomalous reflection phenomena existing in two gratings are confirmed. In addition, a residual reflection which couldn 't be completely cancelled by means of changing strip-thickness is pointed out for a short-circuited Au-grating on YZ LiNbO3 both experimentally and theoretically through extending Chen-Haus 'theory to anisotropic crystals.Finally, two kinds of IDT composed of single electrodes: Au-electrode on YZ LiNbO3 and Al-recessed - groove - electrode on ST-X quartz, are proposed for high internal reflection suppression. The experimental results of bandpass filters constructed with the IDTs mentioned above show a great improvement in passband distortion and a potential usefulness of new structure in high frequency range.展开更多
FAMM（fluorescence alteration of multiple macerals）技术是目前解决烃源岩镜质体反射率抑制问题的唯一有效方法。该文对渤海湾盆地东营凹陷不同类型烃源岩进行FAMM分析的同时,也进行了镜质体反射率测定。在此基础上,综合前人研究成...FAMM（fluorescence alteration of multiple macerals）技术是目前解决烃源岩镜质体反射率抑制问题的唯一有效方法。该文对渤海湾盆地东营凹陷不同类型烃源岩进行FAMM分析的同时,也进行了镜质体反射率测定。在此基础上,综合前人研究成果分析了镜质体反射率抑制与烃源岩质量的关系。研究结果揭示,东营凹陷烃源岩镜质体反射率抑制程度与烃源岩质量关系密切,烃源岩质量越好,其镜质体反射率抑制程度越大。Ⅰ型烃源岩镜质体反射率一般抑制0.20%~0.35%,平均为0.30%;Ⅱ1型烃源岩镜质体反射率一般抑制0.15%~0.30%,平均为0.22%;Ⅱ2型烃源岩镜质体反射率一般抑制0.10%~0.18%,平均为0.15%;而Ⅲ型烃源岩的镜质体反射率一般不抑制或抑制程度很低,为0.0%~0.05%。镜质体反射率受抑制的影响因素复杂,东营凹陷烃源岩镜质体反射率抑制程度与氢指数间具有显著的正相关性,表明东营凹陷烃源岩镜质体反射率受抑制主要与烃源岩富氢密切相关,这与烃源岩质量越好,镜质体反射率抑制程度越高相吻合。展开更多
文摘In the signal processing for metrewave radar, the reflection paths of target echoes can cause severe error in the elevation estimation for the low-angle target tracking. The exact angles of the reflection paths are unknown beforehand, and therefore, the reflection paths can not be suppressed easily. Therefore, in this article, an improved reflection paths suppression approach is presented. A block matrix aggregate is constructed based on the possible angles of the reflection paths. Combined with the beamforming-like processing, a generalized maximum likelihood estimation is derived to optimize the estimation. Moreover, the noise reduction method based on the Toeplitz covariance matrix is used for better performance. This approach is applied to the real data collected by the low-angle tracking radar with 8-channel vertical array. The experiment results show that the reflection effects are reduced and the accuracy of the elevation estimate is improved.
文摘Based on Chen-Haus ' theory~[1] , an experimental research on the reflection of SAW from a short-circuited Au -grating on YZ LiNbO3 and a short-circuited Al- recessed groove grating on ST-X quartz is first presented in this paper where an anomalous reflection phenomena existing in two gratings are confirmed. In addition, a residual reflection which couldn 't be completely cancelled by means of changing strip-thickness is pointed out for a short-circuited Au-grating on YZ LiNbO3 both experimentally and theoretically through extending Chen-Haus 'theory to anisotropic crystals.Finally, two kinds of IDT composed of single electrodes: Au-electrode on YZ LiNbO3 and Al-recessed - groove - electrode on ST-X quartz, are proposed for high internal reflection suppression. The experimental results of bandpass filters constructed with the IDTs mentioned above show a great improvement in passband distortion and a potential usefulness of new structure in high frequency range.
文摘FAMM（fluorescence alteration of multiple macerals）技术是目前解决烃源岩镜质体反射率抑制问题的唯一有效方法。该文对渤海湾盆地东营凹陷不同类型烃源岩进行FAMM分析的同时,也进行了镜质体反射率测定。在此基础上,综合前人研究成果分析了镜质体反射率抑制与烃源岩质量的关系。研究结果揭示,东营凹陷烃源岩镜质体反射率抑制程度与烃源岩质量关系密切,烃源岩质量越好,其镜质体反射率抑制程度越大。Ⅰ型烃源岩镜质体反射率一般抑制0.20%~0.35%,平均为0.30%;Ⅱ1型烃源岩镜质体反射率一般抑制0.15%~0.30%,平均为0.22%;Ⅱ2型烃源岩镜质体反射率一般抑制0.10%~0.18%,平均为0.15%;而Ⅲ型烃源岩的镜质体反射率一般不抑制或抑制程度很低,为0.0%~0.05%。镜质体反射率受抑制的影响因素复杂,东营凹陷烃源岩镜质体反射率抑制程度与氢指数间具有显著的正相关性,表明东营凹陷烃源岩镜质体反射率受抑制主要与烃源岩富氢密切相关,这与烃源岩质量越好,镜质体反射率抑制程度越高相吻合。
