飞行时间二次离子质谱(time-of-flight secondary ion mass spectrometry,TOF-SIMS)作为一种高灵敏度、高分辨率的表面分析技术,在材料科学领域应用广泛。聚焦于TOF-SIMS在钢铁材料分析中的应用,探讨了其在薄膜/钝化膜分析、微量元素残...飞行时间二次离子质谱(time-of-flight secondary ion mass spectrometry,TOF-SIMS)作为一种高灵敏度、高分辨率的表面分析技术,在材料科学领域应用广泛。聚焦于TOF-SIMS在钢铁材料分析中的应用,探讨了其在薄膜/钝化膜分析、微量元素残留、晶界富集、表面基团表征及氢元素分析等方面的潜力。凭借高空间分辨率和卓越的化学灵敏度,TOF-SIMS能提供高精度的表面成分分布、深度剖析与三维成像结果,有效克服了能量色散X射线光谱(EDS)等传统分析方法在灵敏度与元素检测范围上的局限性。通过镀锡板黄斑缺陷、ZM镀层钢板残油及BW600钢晶界元素富集等案例,展示了该技术的实际应用。特别是在氢脆研究中,TOF-SIMS能够高效、精确地表征氢在材料中的分布,为揭示氢脆机理提供了独特优势。综上,TOF-SIMS技术在钢铁材料缺陷分析中具有广阔的应用前景,可为钢铁行业提供精准的分析手段,从而推动相关领域的技术进步。展开更多
Flight feathers represent a hallmark innovation of avian evolution.Recent comparative genomic analyses identified a 284 bp avian-specific highly conserved element(ASHCE)located within the eighth intron of the SIM bHLH...Flight feathers represent a hallmark innovation of avian evolution.Recent comparative genomic analyses identified a 284 bp avian-specific highly conserved element(ASHCE)located within the eighth intron of the SIM bHLH transcription factor 1(Sim1)gene,postulated to act as a cis-regulatory element governing flight feather morphogenesis.To investigate its functional significance,genome-edited(GE)primordial germ cell(PGC)lines carrying targeted ASHCE deletions were generated using CRISPR/Cas9-mediated editing,with germline chimeric males subsequently mated with wild-type(WT)hens to obtain GE progeny.The resulting GE chickens harbored 257-260 bp deletions,excising approximately half of the Sim1-ASHCE sequence.Reverse transcription-quantitative real-time polymerase chain reaction(RT-qPCR)analysis showed an average 0.32-fold reduction in Sim1 expression in the forelimbs of GE embryos at day 8(E8)compared to WT counterparts.Despite this,GE chickens developed structurally normal flight and tail feathers.In situ hybridization localized Sim1 expression to the posterior mesenchyme surrounding flight feather buds in E8 WT embryos,but not within the buds themselves.These results suggest that partial deletion of Sim1-ASHCE,despite diminishing Sim1 expression,does not disrupt flight feather formation.The excised region appears to possess enhancer activity toward Sim1 but is dispensable for flight feather development.Complete ablation of the ASHCE will be necessary to fully resolve the regulatory role of Sim1 in avian feather morphogenesis.展开更多
在控制系统仿真建模中,对于步进电机这一重要功能的准确建模和研究至关重要,对一般步进电机的建模过程进行分析,并利用MATLAB中的动态仿真工具Simulink以及它提供的基于Sim Power System仿真引擎,建立二相混合式步进电机的动态仿真模型...在控制系统仿真建模中,对于步进电机这一重要功能的准确建模和研究至关重要,对一般步进电机的建模过程进行分析,并利用MATLAB中的动态仿真工具Simulink以及它提供的基于Sim Power System仿真引擎,建立二相混合式步进电机的动态仿真模型,通过分析仿真结果来验证所建立的模型的有效性和适用性。展开更多
文摘飞行时间二次离子质谱(time-of-flight secondary ion mass spectrometry,TOF-SIMS)作为一种高灵敏度、高分辨率的表面分析技术,在材料科学领域应用广泛。聚焦于TOF-SIMS在钢铁材料分析中的应用,探讨了其在薄膜/钝化膜分析、微量元素残留、晶界富集、表面基团表征及氢元素分析等方面的潜力。凭借高空间分辨率和卓越的化学灵敏度,TOF-SIMS能提供高精度的表面成分分布、深度剖析与三维成像结果,有效克服了能量色散X射线光谱(EDS)等传统分析方法在灵敏度与元素检测范围上的局限性。通过镀锡板黄斑缺陷、ZM镀层钢板残油及BW600钢晶界元素富集等案例,展示了该技术的实际应用。特别是在氢脆研究中,TOF-SIMS能够高效、精确地表征氢在材料中的分布,为揭示氢脆机理提供了独特优势。综上,TOF-SIMS技术在钢铁材料缺陷分析中具有广阔的应用前景,可为钢铁行业提供精准的分析手段,从而推动相关领域的技术进步。
基金supported by the Ministry of Agriculture and Rural Affairs of the People's Republic of China(125A0607)Department of Science and Technology of Yunnan Province(XDYC-KJLJ-2022-0004)。
文摘Flight feathers represent a hallmark innovation of avian evolution.Recent comparative genomic analyses identified a 284 bp avian-specific highly conserved element(ASHCE)located within the eighth intron of the SIM bHLH transcription factor 1(Sim1)gene,postulated to act as a cis-regulatory element governing flight feather morphogenesis.To investigate its functional significance,genome-edited(GE)primordial germ cell(PGC)lines carrying targeted ASHCE deletions were generated using CRISPR/Cas9-mediated editing,with germline chimeric males subsequently mated with wild-type(WT)hens to obtain GE progeny.The resulting GE chickens harbored 257-260 bp deletions,excising approximately half of the Sim1-ASHCE sequence.Reverse transcription-quantitative real-time polymerase chain reaction(RT-qPCR)analysis showed an average 0.32-fold reduction in Sim1 expression in the forelimbs of GE embryos at day 8(E8)compared to WT counterparts.Despite this,GE chickens developed structurally normal flight and tail feathers.In situ hybridization localized Sim1 expression to the posterior mesenchyme surrounding flight feather buds in E8 WT embryos,but not within the buds themselves.These results suggest that partial deletion of Sim1-ASHCE,despite diminishing Sim1 expression,does not disrupt flight feather formation.The excised region appears to possess enhancer activity toward Sim1 but is dispensable for flight feather development.Complete ablation of the ASHCE will be necessary to fully resolve the regulatory role of Sim1 in avian feather morphogenesis.
文摘在控制系统仿真建模中,对于步进电机这一重要功能的准确建模和研究至关重要,对一般步进电机的建模过程进行分析,并利用MATLAB中的动态仿真工具Simulink以及它提供的基于Sim Power System仿真引擎,建立二相混合式步进电机的动态仿真模型,通过分析仿真结果来验证所建立的模型的有效性和适用性。
