Subjects: Astronomy >> Astrophysical processes submitted time 2023-01-17 Cooperative journals: 《天文研究与技术》
Abstract： Since the discovery of some objects without obvious periodicity, such as fast radio bursts and rotating radio temporary sources, the single pulse search approach has attracted extensive attention of researchers. Meanwhile, the radio telescope equipment is becoming more and more perfect, which brings higher resolution and wider observation space. Therefore, the amount of data generated by pulsar observation increases dramatically, and it is urgent to speed up the data processing of pulsars. The single pulse search in PRESTO (PulsaR Exploration and Search TOolkit) is introduced, the detrending algorithm in single pulse search is optimized by Cython programming, and the parallelization of single pulse search on CPU (Central Processing Units) is realized by Ray Framework. The experimental results show that the parallelization of the optimized single pulse search algorithm can significantly improve the performance of the search program and shorten the data processing time. At the same time, the parallel strategy is only based on CPU, so it can realize high-performance data processing in pure CPU environment without modifying the code.
Subjects: Astronomy >> Astrophysical processes submitted time 2021-07-30 Cooperative journals: 《天文研究与技术》
Abstract：对大规模射电天文巡天项目产生的数据进行单脉冲搜索会产生数以亿计的脉冲星候选体。本文处理了CRAFTS（The Commensal Radio Astronomy FAST Survey）巡天的32万个超宽带数据文件，得到5万个脉冲星候选体。针对CRAFTS单脉冲搜索实验结果中脉冲星候选体仅有1.5%真正具有脉冲星信号的问题，提出三个显著区分脉冲星信号与干扰的特征，并应用到单脉冲筛选流程中。实验表明，改进后的单脉冲筛选工具将需要人工检查脉冲星候选体的数量降低了20%，一定程度上提升了CRAFTS巡天数据的单脉冲搜索效率。
Subjects: Biology >> Bioengineering submitted time 2017-07-24 Cooperative journals: 《中国生物工程杂志》
Abstract：8二甲基异戊烯基柚皮素（8DN）作为生产黄酮类类药物淫羊藿苷的重要前体，在医药合成领域具有重大应用潜力。由于其合成路径及相关基因的复杂性，目前主要通过饲喂8DN的直接前体(柚皮素，异黄腐酚等）的方式合成8DN，而在生物体内全合成8DN的的研究工作还未见报道。为了实现8DN在酿酒酵母体内的生物全合成，该研究通过组合筛选8DN前体物柚皮素合成所需的多种外源基因（TAL，4CL，CHS，CHI），获得30株柚皮素生产菌，发现不同来源的基因组合引起柚皮素产量的明显差异（0.37mg/L-22.33mg/L）。并且利用Delta位点将较优的基因组合整合至酵母基因组，实现了稳定的柚皮素高产菌株（SyBE_Sc02050031）构建。在此基础上进一步导入带有苦参来源的异戊烯基转移酶基因（N8DT）多拷贝质粒，实现8DN合成的完整反应过程，8DN的摇瓶发酵产量达到36.7μg/L。另外通过关键限速酶N8DT的序列优化策略，发现截断定位信号肽序列的N8DT明显提高了从柚皮素到8DN这一关键反应的催化效果，8DN的产量提高到52.6 μg/L（144.2%）。该研究首次在酿酒酵母中成功构建高产8DN的生物全合成路径，为在微生物体内合成其他黄酮类天然产物提供了参考，具有重要的指导意义。
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