一种基于模式搜索算法的基阵波束优化方法

波束形成在声纳/雷达信号处理中占有重要的地位,而设计出满足要求的波束形状是声纳/雷达信号空间处理的重要内容。自适应波束形成算法理论上可以获得最优的工作性能,但其计算复杂度高、宽容性差等缺点严重地限制了这些算法的实际应用。本文采用基于模式搜索的波束优化算法,获得了与实际接收数据无关的、类似于窗函数的幅度权系数。与加窗波束形成算法相比,这种方法可以在保证主瓣宽度不展宽的情况下,有效降低旁瓣级,并且,这种方法对基阵的几何形状没有任何限制。     

Comparative identification of the metabolites of dehydrocorydaline from rat plasma,bile, urine and feces by both the targeted and untargeted liquid chromatography/mass spectrometry strategies

Severe interference from the endogenous substances is often encountered in characterizing the drug metabolites by liquid chromatography/mass spectrometry using data-dependent acquisition (DDA). To add a precursor ions list (PIL) by DDA or apply data-independent acquisition (DIA) coupled with post-acquisition data processing (such as mass defect filtering, MDF) may assist to target more metabolites from the complex biosamples. Dehydrocorynine (DHC) is a bioactive alkaloid compound rich in Corydalis yanhusuo. We integrated both PIL-DDA and DIA-MDF strategies to probe the metabolites of DHC simultaneously from the rat plasma, bile, urine, and feces. Chromatographic separation was performed on an HSS C18 SB column. The positive-mode collision-induced dissociation-MS² data of DHC metabolites were recorded by PIL-DDA on both the QTrap 4500 and Vion IM-QTOF mass spectrometers, and by HDMS^E on Vion IM-QTOF. Efficient workflows to process the high-definition DDA (HDDDA) and HDMS^E data were elaborated. Totally 40 metabolites (orally administrated at the dose of 100 mg/kg) were identified or tentatively characterized, involving 30 from bile, 16 from feces, 7 from plasma, and 18 from urine. The methoxyls and C-5/C-6/C-8 were the main sites prone to be metabolized via demethylation and oxidation, and further glucuronic acid conjugation and sulfuric acid conjugation. Compared with literature, we can newly discover 17 metabolites in bile, and, for the first time, report the metabolites of DHC from rat urine and feces. Conclusively, the presented PIL-DDA and DIA-MDF strategies are powerful in elucidating the drug metabolites, which thus provides reference to characterizing the metabolic profiles of traditional Chinese medicine components.