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泡沫铜无溶剂催化氧化苄醇的应用研究 被引量:1
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作者 马佳美 张淑华 +1 位作者 钟伟 沈忠权 《化学研究与应用》 CAS CSCD 北大核心 2021年第1期129-136,共8页
本文报道了在模拟的鼓泡床反应器中,以1-甲基咪唑(NMI)和2,2,6,6-四甲基-1-哌啶基氧基(TEMPO)作为助催化剂,空气泵鼓入空气作为氧源,泡沫铜作为催化剂,室温、无溶剂条件下催化氧化苄醇的应用研究。具体优化条件为:以50 mmol苯甲醇为反... 本文报道了在模拟的鼓泡床反应器中,以1-甲基咪唑(NMI)和2,2,6,6-四甲基-1-哌啶基氧基(TEMPO)作为助催化剂,空气泵鼓入空气作为氧源,泡沫铜作为催化剂,室温、无溶剂条件下催化氧化苄醇的应用研究。具体优化条件为:以50 mmol苯甲醇为反应底物,2.5 mmol泡沫铜,0.625 mmol NMI,2.5 mmol TEMPO,空气流速300mL·min-1,室温无溶剂条件下反应6小时,苯甲醛产率达99%以上,并且催化剂在经过6次循环使用后产率仍然达82%。 展开更多
关键词 醇氧化 无溶剂 泡沫铜 鼓泡床反应器
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基于猪繁殖与呼吸综合征病毒ORF2a基因的RT-RAA-LF检测方法的建立 被引量:3
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作者 陈素贞 马佳镁 +4 位作者 黄春媛 范悦轩 郑佳馨 刘光亮 曹宗喜 《中国兽医科学》 CAS CSCD 北大核心 2023年第10期1249-1253,共5页
本研究针对猪繁殖与呼吸综合征病毒ORF2a基因序列,设计特异性RAA引物和标记探针,通过反转录酶与重组酶扩增结合,旨在建立一种高效检测PRRSV的基于侧流层析试纸条的可视化RT-RAA方法。结果,建立的RT-RAA-LF方法的最佳反应条件是39℃恒温... 本研究针对猪繁殖与呼吸综合征病毒ORF2a基因序列,设计特异性RAA引物和标记探针,通过反转录酶与重组酶扩增结合,旨在建立一种高效检测PRRSV的基于侧流层析试纸条的可视化RT-RAA方法。结果,建立的RT-RAA-LF方法的最佳反应条件是39℃恒温扩增10 min,可在2 min内实现对检测结果的可视化判定;该方法特异性强,仅对PRRSV出现阳性扩增,对本研究中其他病原均无交叉反应;以含PRRSV ORF2a基因全段序列的重组质粒作为模板,RT-RAA-LF的检出限为160 copies/μL。应用建立的RT-RAA-LF方法对临床采集的160份样本进行检测,与PCR方法进行比较,两种方法的符合率为96.8%(65/68),一致性检验为χ2<3.84,在95%的置信区间内没有显著性差异,当中3份临床样品在PCR检测中为阴性。综上,基于PRRSV ORF2a建立的RT-RAA-LF方法操作简单,对仪器设备要求不高,能够高效且直观的实现临床检测,满足现场检测的要求,对猪养殖场快速诊断和防控PRRSV具有重要意义。 展开更多
关键词 猪繁殖与呼吸综合征病毒 ORF2a 侧流层析试纸条 重组酶介导扩增法(RAA) 临床检测
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EXPERIMENTAL INVESTIGATION OF CHARACTERISTIC FREQUENCY IN UNSTEADY HYDRAULIC BEHAVIOUR OF A LARGE HYDRAULIC TURBINE 被引量:12
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作者 WANG Fu-jun LI Xiao-qin +2 位作者 ma jia-mei YANG Min ZHU Yu-liang 《Journal of Hydrodynamics》 SCIE EI CSCD 2009年第1期12-19,共8页
The features of unsteady flow such as pressure variation and fluctuation in a large hydraulic turbine usually lead to the instability of operation. This article reports the recent in site investigation concerning the ... The features of unsteady flow such as pressure variation and fluctuation in a large hydraulic turbine usually lead to the instability of operation. This article reports the recent in site investigation concerning the characteristic frequencies in pressure fluctuation, shaft torsional oscillation and structural vibration of a prototype 700 MW Francis turbine unit. The investigation was carried out for a wide load range of 200 MW-700 MW in the condition of water head 57 m-90 m. An extensive analysis of both time-history and frequency data of these unsteady hydraulic behaviours was conducted. It was observed that the pressure fluctuation in a draft tube is stronger than that in upstream flow passage. The low frequency with about one third of rotation frequency is dominative for the pressure fluctuation in part load range. Also the unsteady features of vibration of head cover and torsional oscillation of shaft exhibited the similar features. Numerical analysis showed that the vibration and oscillation are caused by vortex rope in the draft tube. In addition, a strong vibration with special characteristic frequency was observed for the head cover in middle load range. The pressure fluctuation in the draft tube with the same frequency was also recorded. Because this special vibration has appeared in the designed normal running condition, it should be avoided by carefully allocating power load in the future operation. 展开更多
关键词 hydraulic turbine part load swirling flow unsteady behaviour characteristic frequency power load allocation
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