采用生命周期分析(LCA)方法,基于我国核能产业代表性设施和典型技术工艺,调查一批新的基础数据和评价参数,计算现阶段核能系统生命周期的温室气体归一化排放量,结果为5.31 g CO_(2)/(kW.h),其中核电站占27%、核燃料循环设施占73%(前段占...采用生命周期分析(LCA)方法,基于我国核能产业代表性设施和典型技术工艺,调查一批新的基础数据和评价参数,计算现阶段核能系统生命周期的温室气体归一化排放量,结果为5.31 g CO_(2)/(kW.h),其中核电站占27%、核燃料循环设施占73%(前段占41%、后段占32%)。“碳中和”目标下核能系统有进一步“脱碳”的愿景,建议加强核燃料循环设施减碳路径的顶层设计研究,废弃物资源循环利用等减碳技术路径研究,逐步完善核能产业链的碳足迹核算技术体系。展开更多
烟碱具有明显的神经药理学活性,对多种中枢神经系统疾病具有干预作用,然而烟碱入脑后对脑区内源性代谢物的影响尚不清楚。研究烟碱暴露后对小鼠脑内内源性代谢物的影响,可为阐明烟碱的多重生理学效应提供更加全面的物质基础。本文基于...烟碱具有明显的神经药理学活性,对多种中枢神经系统疾病具有干预作用,然而烟碱入脑后对脑区内源性代谢物的影响尚不清楚。研究烟碱暴露后对小鼠脑内内源性代谢物的影响,可为阐明烟碱的多重生理学效应提供更加全面的物质基础。本文基于超高效液相色谱-串联质谱(UHPLC-MS/MS)及代谢组学分析方法,系统考察了烟碱多次暴露后对小鼠脑内内源性代谢产物的影响,并进一步采用质谱成像法,直观获取烟碱引发的差异性代谢物在不同脑区的分布及变化差异。实验结果如下:本研究共鉴定到759种代谢物,烟碱暴露后共筛选到575个显著差异性代谢物,其中434个代谢物下调,141个代谢物上调;通过京都基因和基因组数据库(Kyoto Encyclopedia of Genes and Genomes,KEGG)通路富集分析表明烟碱暴露后主要影响到脑内必需氨基酸代谢、脂质代谢、核苷酸代谢、碳水化合物代谢、辅因子和维生素代谢以及其他氨基酸代谢通路;进一步通过质谱成像法分析差异性代谢物在脑内的分布特征,结果表明烟碱暴露后全脑范围内胆碱、丝氨酸、天冬氨酸及苹果酸含量都被显著下调,皮层区域牛磺酸、海马区域乙酰基肉碱以及纹状体区域的腺苷类物质均被显著影响。这些结果为进一步揭示烟碱暴露对中枢神经系统的影响提供了新的实验依据。展开更多
A three-dimensional path-planning approach has been developed to coordinate multiple fixed-wing unmanned aerial vehicles(UAVs)while avoiding collisions.The hierarchical path-planning architecture that divides the path...A three-dimensional path-planning approach has been developed to coordinate multiple fixed-wing unmanned aerial vehicles(UAVs)while avoiding collisions.The hierarchical path-planning architecture that divides the path-planning process into two layers is proposed by designing the velocityobstacle strategy for satisfying timeliness and effectiveness.The upper-level layer focuses on creating an efficient Dubins initial path considering the dynamic constraints of the fixed wing.Subsequently,the lower-level layer detects potential collisions and adjusts its flight paths to avoid collisions by using the threedimensional velocity obstacle method,which describes the maneuvering space of collision avoidance as the intersection space of half space.To further handle the dynamic and collisionavoidance constraints,a priority mechanism is designed to ensure that the adjusted path is still feasible for fixed-wing UAVs.Simulation experiments demonstrate the effectiveness of the proposed method.展开更多
文摘采用生命周期分析(LCA)方法,基于我国核能产业代表性设施和典型技术工艺,调查一批新的基础数据和评价参数,计算现阶段核能系统生命周期的温室气体归一化排放量,结果为5.31 g CO_(2)/(kW.h),其中核电站占27%、核燃料循环设施占73%(前段占41%、后段占32%)。“碳中和”目标下核能系统有进一步“脱碳”的愿景,建议加强核燃料循环设施减碳路径的顶层设计研究,废弃物资源循环利用等减碳技术路径研究,逐步完善核能产业链的碳足迹核算技术体系。
文摘烟碱具有明显的神经药理学活性,对多种中枢神经系统疾病具有干预作用,然而烟碱入脑后对脑区内源性代谢物的影响尚不清楚。研究烟碱暴露后对小鼠脑内内源性代谢物的影响,可为阐明烟碱的多重生理学效应提供更加全面的物质基础。本文基于超高效液相色谱-串联质谱(UHPLC-MS/MS)及代谢组学分析方法,系统考察了烟碱多次暴露后对小鼠脑内内源性代谢产物的影响,并进一步采用质谱成像法,直观获取烟碱引发的差异性代谢物在不同脑区的分布及变化差异。实验结果如下:本研究共鉴定到759种代谢物,烟碱暴露后共筛选到575个显著差异性代谢物,其中434个代谢物下调,141个代谢物上调;通过京都基因和基因组数据库(Kyoto Encyclopedia of Genes and Genomes,KEGG)通路富集分析表明烟碱暴露后主要影响到脑内必需氨基酸代谢、脂质代谢、核苷酸代谢、碳水化合物代谢、辅因子和维生素代谢以及其他氨基酸代谢通路;进一步通过质谱成像法分析差异性代谢物在脑内的分布特征,结果表明烟碱暴露后全脑范围内胆碱、丝氨酸、天冬氨酸及苹果酸含量都被显著下调,皮层区域牛磺酸、海马区域乙酰基肉碱以及纹状体区域的腺苷类物质均被显著影响。这些结果为进一步揭示烟碱暴露对中枢神经系统的影响提供了新的实验依据。
基金supported by the National Science Fund for Distinguished Young Scholars(52425211)BIT Research Fund Program for Young Scholars(XSQD-202201005).
文摘A three-dimensional path-planning approach has been developed to coordinate multiple fixed-wing unmanned aerial vehicles(UAVs)while avoiding collisions.The hierarchical path-planning architecture that divides the path-planning process into two layers is proposed by designing the velocityobstacle strategy for satisfying timeliness and effectiveness.The upper-level layer focuses on creating an efficient Dubins initial path considering the dynamic constraints of the fixed wing.Subsequently,the lower-level layer detects potential collisions and adjusts its flight paths to avoid collisions by using the threedimensional velocity obstacle method,which describes the maneuvering space of collision avoidance as the intersection space of half space.To further handle the dynamic and collisionavoidance constraints,a priority mechanism is designed to ensure that the adjusted path is still feasible for fixed-wing UAVs.Simulation experiments demonstrate the effectiveness of the proposed method.
