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相干信号子空间方法(CSM)一直是宽带信号波达方位(DOA)估计的研究热点.首先建立了宽带阵列信号处理的模型,在此基础上,分析了宽带高分辨方位估计在不同聚焦矩阵下的几种CSM算法.进行了计算机仿真试验,在理论上分析和比较了各种方法的性能,验证了宽带DOA估计算法的有效性.仿真结果表明,CSM方法具有良好的分辨性能,在低信噪比的条件下仍具有一定的分辨能力,但是需要进行方向的预估. 相似文献
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The new accelerator project ( HIRFL-CSR ) constructed at the Heavy Ion Research Facility in Lanzhou (HIRFL) is approaching completion. It is a multipurpose cooler-storage-ring system, consisting of a maim ring (CSRm), an experimental ring (CSRe) and two transfer beam lines. The UHV system of CSRm is the most representative subsystem in the project. To minimize the beam loss due to charge exchange of the heavy ions with the residual gas molecules, the pressure of the CSRm vacuum system should reach 3.5 × 10^-9 Pa (N2 equivalent) and the pressure of 8 × 10^-10 Pa is expected for very heavy ion such as uranium to make its lifetime longer than 50 s in the ring. Now, the vacuum system of CSRm has been completed and a pressure less than 5 × 10^-10 Pa has been obtained. In this paper the layout of the CSRm vacuum system, the vacuum equipment in CSRm, the treatment method for the CSRm vacuum chambers, and the installation and operation of the system will be reported. 相似文献
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本试验以‘红地球’ב金星无核’及其179株杂交后代,‘着色香’ב维多利亚’及其192株杂交后代作为试验材料,进行灰霉病抗性鉴定及遗传分析。结果表明:在‘红地球’与‘金星无核’及其杂交后代中,子代叶片病斑平均值为855.19 mm~2,超低亲率为15.64%,变异系数为56.18%,遗传传递力为119.95%;在‘着色香’与‘维多利亚’及其杂交后代中,子代叶片病斑平均值为828.36 mm~2,超低亲率为15.10%,变异系数为37.80%,遗传传递力为93.87%。这两个群体抗病性性状发生显著性分离,呈连续性分布,分布广泛,具有典型的数量性状遗传特征。本文筛选出对灰霉病抗性强的单株,为葡萄抗灰霉病育种工作提供了一定的借鉴。 相似文献
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通过对作用在汽轮机上的管道力和汽缸上存在的温差分析,说明了温差是引起汽缸左右偏差的主要原因。根据汽轮机滑销系统的设置特点,验证了该偏差值对机组静体部分的中心偏移量影响是有限的,不会导致机组的动静擦碰。得出了机组启动时,不能以汽缸左右偏差值的大小作为评判停机依据的结论。 相似文献