本试验旨在利用Meta分析探究常规饲粮下生猪氮排泄量及其变异范围,并建立不同生长阶段生猪氮排泄量的预测模型。检索2000—2021年中外文数据库(Web of Science、PubMed、ScienceDirect、中国知网、维普和万方)中相关文献,以文献中不同...本试验旨在利用Meta分析探究常规饲粮下生猪氮排泄量及其变异范围,并建立不同生长阶段生猪氮排泄量的预测模型。检索2000—2021年中外文数据库(Web of Science、PubMed、ScienceDirect、中国知网、维普和万方)中相关文献,以文献中不同阶段生猪的摄入氮(NI)、粪氮(FN)、尿氮(UN)和总氮排泄量(NE)数据为基础,使用倒方差法对生猪氮排泄量进行Meta分析,建立不同阶段生猪氮排泄量的预测模型。结果表明:保育猪、育肥前期猪和育肥后期猪的NI与FN、UN和NE均有较强的相关性(P<0.01),不同生长阶段生猪基于NI的氮排泄量预测模型为:保育猪NE=0.460NI-2.255,FN=0.197NI-1.314,UN=0.264NI-0.965;育肥前期猪NE=0.583NI-5.370,FN=0.139NI+1.340,UN=0.446NI-6.788;育肥后期猪NE=0.698NI-10.251,FN=0.143NI+0.422,UN=0.551NI-10.451。本试验通过Meta分析建立了基于生猪NI的各生长阶段的FN、UN和NE预测模型,可用于预测不同生长阶段生猪的氮排泄量,为养殖粪污资源化利用提供基础参数和方法支撑。展开更多
建立一种新型的在线净化前处理装置结合高效液相色谱-串联质谱(high performance liquid chromatography-tandem with mass spectrometry,HPLC-MS/MS)法测定香精香料中的麦角甾醇和麦角甾酮。该前处理装置结合基质分散萃取和柱层析对样...建立一种新型的在线净化前处理装置结合高效液相色谱-串联质谱(high performance liquid chromatography-tandem with mass spectrometry,HPLC-MS/MS)法测定香精香料中的麦角甾醇和麦角甾酮。该前处理装置结合基质分散萃取和柱层析对样品进行萃取和净化,之后对样品进行浓缩并利用HPLC-MS/MS分析测定。HPLC-MS/MS方法以甲醇和水为流动相,0.4 mL/min流速条件下梯度洗脱,采用C_(18)色谱柱进行液相色谱分离,大气压正离子方式电离,多重反应监测模式检测,内标法进行定量分析。结果表明,该方法前处理方便且稳定性强,溶剂可回收,净化萃取浓缩为一体;目标物质麦角甾醇和麦角甾酮能在5 min内得到分离检测,在1.5~250μg/m L范围内具有较好的线性,各待测物的线性相关系数均大于0.999,检出限为0.32~0.35μg/mL,在不同添加水平条件下,平均回收率为86%~96%,相对标准偏差在3.1%~3.6%之间。本方法能较好地应用于香精香料实际样品中麦角甾醇和麦角甾酮的测定。展开更多
According to the mechanism of the arc plasma heating effect,and from a phenomenological perspective of view,the plasma actuation was simplified as heating energy injected into the supersonic flow field for the numeric...According to the mechanism of the arc plasma heating effect,and from a phenomenological perspective of view,the plasma actuation was simplified as heating energy injected into the supersonic flow field for the numerical research on controlling detached shock of the blunt body in non-center symmetrical positions.Besides,experimental research on the form and strength of detached shock wave control by plasma aerodynamic actuation in non-center symmetrical positions was conducted in a high-speed shock tunnel(M=2).The results showed that the detached distance of shock wave increased and the strength of normal shock wave ahead of the detached shock wave reduced when plasma actuation was applied.The control effect was greatly improved after the magnetic field was applied and the effect of upwind-direction flow was the best one.When the upwind-direction flow was applied with 1000 V voltage actuation,the distance of detached shock wave would increase from 3.4 to 7.6 mm and the time average strength of normal shock wave was weaken by 5.5%.At last,the mechanism of plasma actuation on controlling the detached shock wave was briefly analyzed.展开更多
文摘本试验旨在利用Meta分析探究常规饲粮下生猪氮排泄量及其变异范围,并建立不同生长阶段生猪氮排泄量的预测模型。检索2000—2021年中外文数据库(Web of Science、PubMed、ScienceDirect、中国知网、维普和万方)中相关文献,以文献中不同阶段生猪的摄入氮(NI)、粪氮(FN)、尿氮(UN)和总氮排泄量(NE)数据为基础,使用倒方差法对生猪氮排泄量进行Meta分析,建立不同阶段生猪氮排泄量的预测模型。结果表明:保育猪、育肥前期猪和育肥后期猪的NI与FN、UN和NE均有较强的相关性(P<0.01),不同生长阶段生猪基于NI的氮排泄量预测模型为:保育猪NE=0.460NI-2.255,FN=0.197NI-1.314,UN=0.264NI-0.965;育肥前期猪NE=0.583NI-5.370,FN=0.139NI+1.340,UN=0.446NI-6.788;育肥后期猪NE=0.698NI-10.251,FN=0.143NI+0.422,UN=0.551NI-10.451。本试验通过Meta分析建立了基于生猪NI的各生长阶段的FN、UN和NE预测模型,可用于预测不同生长阶段生猪的氮排泄量,为养殖粪污资源化利用提供基础参数和方法支撑。
文摘建立一种新型的在线净化前处理装置结合高效液相色谱-串联质谱(high performance liquid chromatography-tandem with mass spectrometry,HPLC-MS/MS)法测定香精香料中的麦角甾醇和麦角甾酮。该前处理装置结合基质分散萃取和柱层析对样品进行萃取和净化,之后对样品进行浓缩并利用HPLC-MS/MS分析测定。HPLC-MS/MS方法以甲醇和水为流动相,0.4 mL/min流速条件下梯度洗脱,采用C_(18)色谱柱进行液相色谱分离,大气压正离子方式电离,多重反应监测模式检测,内标法进行定量分析。结果表明,该方法前处理方便且稳定性强,溶剂可回收,净化萃取浓缩为一体;目标物质麦角甾醇和麦角甾酮能在5 min内得到分离检测,在1.5~250μg/m L范围内具有较好的线性,各待测物的线性相关系数均大于0.999,检出限为0.32~0.35μg/mL,在不同添加水平条件下,平均回收率为86%~96%,相对标准偏差在3.1%~3.6%之间。本方法能较好地应用于香精香料实际样品中麦角甾醇和麦角甾酮的测定。
基金supported by the National Natural Science Foundation of China (Grant Nos. 51276197,51207169)
文摘According to the mechanism of the arc plasma heating effect,and from a phenomenological perspective of view,the plasma actuation was simplified as heating energy injected into the supersonic flow field for the numerical research on controlling detached shock of the blunt body in non-center symmetrical positions.Besides,experimental research on the form and strength of detached shock wave control by plasma aerodynamic actuation in non-center symmetrical positions was conducted in a high-speed shock tunnel(M=2).The results showed that the detached distance of shock wave increased and the strength of normal shock wave ahead of the detached shock wave reduced when plasma actuation was applied.The control effect was greatly improved after the magnetic field was applied and the effect of upwind-direction flow was the best one.When the upwind-direction flow was applied with 1000 V voltage actuation,the distance of detached shock wave would increase from 3.4 to 7.6 mm and the time average strength of normal shock wave was weaken by 5.5%.At last,the mechanism of plasma actuation on controlling the detached shock wave was briefly analyzed.
