An Arnoldi's method with new iteration pattern,which was designed for solving a large unsymmetric eigenvalue problem introduced by displacement-pressure FE (Finite Element) pattern of a fluid-structure interaction...An Arnoldi's method with new iteration pattern,which was designed for solving a large unsymmetric eigenvalue problem introduced by displacement-pressure FE (Finite Element) pattern of a fluid-structure interaction system,was adopted here to get the dynamic characteristics of the semi-submerged body. The new iteration pattern could be used efficiently to obtain the Arnoldi's vectors in the shift-frequency technique,which was used for the zero-frequency problem. Numerical example showed that the fluid-structure interaction is one of the important factors to the dynamic characteristics of large semi-submerged thin-walled structures.展开更多
严寒地区冰雪飞溅问题对高速铁路运营安全性有直接影响,现场调研发现多处冰块脱落击打应答器的现象,而国内外对此研究尚未见文献报道。采用基于离散元-多柔性体动力学-计算流体力学(discrete element method-multi flexible body dynami...严寒地区冰雪飞溅问题对高速铁路运营安全性有直接影响,现场调研发现多处冰块脱落击打应答器的现象,而国内外对此研究尚未见文献报道。采用基于离散元-多柔性体动力学-计算流体力学(discrete element method-multi flexible body dynamics-computational fluid dynamics, DEM-MFBD-CFD)耦合分析法,建立车厢底板结冰脱落击打应答器模型,并借助风洞和现场试验结果,验证了模型的可靠性;基于建立的分析模型研究不同列车速度、风压变化、冰块质量等因素对应答器击打的受力影响。结果表明:应答器受到的最大应力随列车运行速度呈现幂函数增长关系,当行车速度增大到350 km/h时,最大应力达15.591 MPa,约为150 km/h时的3.5倍;且随冰块质量增加应答器最大应力呈现先迅速增加后缓慢增长趋势;当横风风速为5~20 m/s作用时,应答器表面所受到的最大应力相差不大,表明横风对冰雪击打应答器作用可忽略不计;为减小冰雪飞溅击打应答器危害,可采取除融雪手段、列车降速等措施。展开更多
目的探讨基于SNaPshot技术的精液特异性编码区单核苷酸多态性(coding region single nucleo⁃tide polymorphism,cSNP)遗传标记检测在精液(斑)溯源及混合体液(斑)鉴定中的可行性。方法制备16例精液斑和11例精液-静脉血混合斑样本,提取其...目的探讨基于SNaPshot技术的精液特异性编码区单核苷酸多态性(coding region single nucleo⁃tide polymorphism,cSNP)遗传标记检测在精液(斑)溯源及混合体液(斑)鉴定中的可行性。方法制备16例精液斑和11例精液-静脉血混合斑样本,提取其基因组DNA(genomic DNA,gDNA)和总RNA,并将总RNA逆转录为互补DNA(complementary DNA,cDNA)。在已验证的精液特异性mRNA编码基因上筛选cSNP遗传标记。基于SNaPshot技术构建cSNP复合检测体系并通过CE对样本进行基因分型。结果成功构建了包含5个精液特异性cSNP的复合检测体系。在16例精液样本中,除了位于TGM4基因上的cSNP在cDNA的检测结果中出现等位基因丢失外,其余cSNP的gDNA和cDNA分型结果高度一致。检测精液-静脉血混合斑时,检出的cSNP分型结果均与精液提供者的基因型一致,未受到静脉血提供者基因型的干扰。结论应用SNaPshot技术检测精液特异性cSNP的方法可以应用于法医学精液(斑)的基因分型,并为混合体液(斑)中精液来源个体的判定提供信息。展开更多
文摘An Arnoldi's method with new iteration pattern,which was designed for solving a large unsymmetric eigenvalue problem introduced by displacement-pressure FE (Finite Element) pattern of a fluid-structure interaction system,was adopted here to get the dynamic characteristics of the semi-submerged body. The new iteration pattern could be used efficiently to obtain the Arnoldi's vectors in the shift-frequency technique,which was used for the zero-frequency problem. Numerical example showed that the fluid-structure interaction is one of the important factors to the dynamic characteristics of large semi-submerged thin-walled structures.
文摘目的探讨基于SNaPshot技术的精液特异性编码区单核苷酸多态性(coding region single nucleo⁃tide polymorphism,cSNP)遗传标记检测在精液(斑)溯源及混合体液(斑)鉴定中的可行性。方法制备16例精液斑和11例精液-静脉血混合斑样本,提取其基因组DNA(genomic DNA,gDNA)和总RNA,并将总RNA逆转录为互补DNA(complementary DNA,cDNA)。在已验证的精液特异性mRNA编码基因上筛选cSNP遗传标记。基于SNaPshot技术构建cSNP复合检测体系并通过CE对样本进行基因分型。结果成功构建了包含5个精液特异性cSNP的复合检测体系。在16例精液样本中,除了位于TGM4基因上的cSNP在cDNA的检测结果中出现等位基因丢失外,其余cSNP的gDNA和cDNA分型结果高度一致。检测精液-静脉血混合斑时,检出的cSNP分型结果均与精液提供者的基因型一致,未受到静脉血提供者基因型的干扰。结论应用SNaPshot技术检测精液特异性cSNP的方法可以应用于法医学精液(斑)的基因分型,并为混合体液(斑)中精液来源个体的判定提供信息。