The purpose of this letter is to present the corrected expressions for the four-pole transmission matrix for a duct with a linear temperature gradient and an exponential temperature profile, described in Sujith [1]. T...The purpose of this letter is to present the corrected expressions for the four-pole transmission matrix for a duct with a linear temperature gradient and an exponential temperature profile, described in Sujith [1]. The corrected equations are used in the analyses of a duct that is driven by a piston at one end and a rigid termination at the other end and the gas has a linear and exponential temperature gradients. The acoustic pressure and particle velocity along the duct are calculated and the theoretical results are compared with predictions using finite element analysis.展开更多
目的采用超高效液相色谱串联四极杆飞行时间质谱联用(ultrahigh performance liquid chromatography-four-stage pole-time-of-flight tandem mass spectrometry,UPLC-Q-TOF-MS)技术鉴定茯苓水提物和醇提物中化学成分。方法加热回流提...目的采用超高效液相色谱串联四极杆飞行时间质谱联用(ultrahigh performance liquid chromatography-four-stage pole-time-of-flight tandem mass spectrometry,UPLC-Q-TOF-MS)技术鉴定茯苓水提物和醇提物中化学成分。方法加热回流提取茯苓水提物和醇提物样品,进行UPLC-Q-TOF-MS检测,所得数据通过与对照品和文献MS数据比对鉴定其化学组分;进一步采用大孔吸附树脂纯化水提物,收集4种不同极性馏分(水洗脱、30%乙醇洗脱、75%乙醇洗脱、95%乙醇洗脱)并通过UPLC-Q-TOF-MS鉴定其化学组成。对比分析水提物和醇提物、4种不同极性馏分、大孔吸附树脂纯化前后水提物成分的变化。结果茯苓水提物和醇提物中总共鉴定出78种化合物,其中水提物28种,醇提物70种。78种化合物中69种为三萜类,其他9种为氨基酸、核苷酸、苯丙素类等;水提物经大孔树脂纯化后4个馏分中共检测到44种化学成分,在水洗脱物中鉴定出7种,30%乙醇洗脱物中鉴定出15种,75%乙醇洗脱物中鉴定出36种,95%乙醇洗脱物中鉴定出24种。相比于纯化前,新检测到23种成分,20种为三萜类。结论相较于水提物,醇提物中检测到更多三萜化合物;大孔吸附树脂可以富集水提物中三萜类成分。研究结果为茯苓物质基础研究提供了参考。展开更多
文摘The purpose of this letter is to present the corrected expressions for the four-pole transmission matrix for a duct with a linear temperature gradient and an exponential temperature profile, described in Sujith [1]. The corrected equations are used in the analyses of a duct that is driven by a piston at one end and a rigid termination at the other end and the gas has a linear and exponential temperature gradients. The acoustic pressure and particle velocity along the duct are calculated and the theoretical results are compared with predictions using finite element analysis.
文摘目的采用超高效液相色谱串联四极杆飞行时间质谱联用(ultrahigh performance liquid chromatography-four-stage pole-time-of-flight tandem mass spectrometry,UPLC-Q-TOF-MS)技术鉴定茯苓水提物和醇提物中化学成分。方法加热回流提取茯苓水提物和醇提物样品,进行UPLC-Q-TOF-MS检测,所得数据通过与对照品和文献MS数据比对鉴定其化学组分;进一步采用大孔吸附树脂纯化水提物,收集4种不同极性馏分(水洗脱、30%乙醇洗脱、75%乙醇洗脱、95%乙醇洗脱)并通过UPLC-Q-TOF-MS鉴定其化学组成。对比分析水提物和醇提物、4种不同极性馏分、大孔吸附树脂纯化前后水提物成分的变化。结果茯苓水提物和醇提物中总共鉴定出78种化合物,其中水提物28种,醇提物70种。78种化合物中69种为三萜类,其他9种为氨基酸、核苷酸、苯丙素类等;水提物经大孔树脂纯化后4个馏分中共检测到44种化学成分,在水洗脱物中鉴定出7种,30%乙醇洗脱物中鉴定出15种,75%乙醇洗脱物中鉴定出36种,95%乙醇洗脱物中鉴定出24种。相比于纯化前,新检测到23种成分,20种为三萜类。结论相较于水提物,醇提物中检测到更多三萜化合物;大孔吸附树脂可以富集水提物中三萜类成分。研究结果为茯苓物质基础研究提供了参考。
