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球囊扩张式冠脉支架扩张变形机理的数值方法研究 被引量:1
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作者 江旭东 滕晓艳 +1 位作者 史冬岩 冯海全 《功能材料》 EI CAS CSCD 北大核心 2016年第3期56-63,共8页
通过非线性有限元方法,建立了球囊扩张式冠脉支架自由扩张和狭窄血管体内扩张的数值计算模型。针对两种不同联接筋结构的冠脉支架,分析了S型和N型支架的自由扩张性能和介入狭窄血管后的体内扩张性能,研究了支架结构对血管组织机械损伤... 通过非线性有限元方法,建立了球囊扩张式冠脉支架自由扩张和狭窄血管体内扩张的数值计算模型。针对两种不同联接筋结构的冠脉支架,分析了S型和N型支架的自由扩张性能和介入狭窄血管后的体内扩张性能,研究了支架结构对血管组织机械损伤的影响机理。数值模拟结果表明,在自由扩张阶段,S型和N型支架变形均匀,两种支架的径向回弹率和轴向短缩率趋于一致,并且具有良好的扩张均匀性与一致性,有利于支架扩张狭窄血管和在血管内的精确定位。在体内扩张阶段,由于狭窄血管的约束作用,S型和N型支架的径向回弹率均高于自由扩张阶段,轴向短缩率均低于自由扩张阶段;但是S型支架介入狭窄血管后的径向回弹率和轴向短缩率略高于N型支架,引起了更低的血管应力水平和应力梯度,减少了血管组织的机械损伤,降低了支架介入术后的血管内再狭窄率。综上,提出的计算模型对于冠脉支架的生物力学性能评估、结构优化设计与介入术后的血管损伤评价提供了重要的理论依据。 展开更多
关键词 冠脉支架 扩张变形 非线性有限元 血管损伤 再狭窄
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冠脉支架体外扩张过程的有限元分析 被引量:5
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作者 郭飞飞 冯海全 +1 位作者 江旭东 韩青松 《机械设计与制造》 北大核心 2012年第10期237-239,共3页
冠脉支架植入术已成为治疗冠心病的重要手段,使用支架时,对支架有一个预压缩的过程,从而使其固定在球囊上,然后才能进行后续的扩张操作。研究利用有限元方法,在不考虑支架与血管的相互作用及承受血管内脉动载荷的情况下,模拟了三种不同... 冠脉支架植入术已成为治疗冠心病的重要手段,使用支架时,对支架有一个预压缩的过程,从而使其固定在球囊上,然后才能进行后续的扩张操作。研究利用有限元方法,在不考虑支架与血管的相互作用及承受血管内脉动载荷的情况下,模拟了三种不同材料(CoCr合金,316L不锈钢和Mg合金)但具有相同结构的支架预压缩和自由扩张的过程。通过设定有限元模型的网格,边界条件,载荷等关键因素,得出不同材料支架的变形机理,定量地比较了每种支架的径向回弹,轴向缩短等力学性能参数并预测了支架的安全系数。 展开更多
关键词 冠脉支架 力学性能 扩张变形 有限元分析
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Seismic facies response of tectonics and direction of block movement in the northeastern South China Sea 被引量:1
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作者 陈洁 钟广见 刘少华 《Applied Geophysics》 SCIE CSCD 2010年第4期306-314,399,共10页
The close relationship between the structure,evolution,and resources environment of the South China Sea is a current research focus and also a focal point of our study.In this paper,we use regional seismic sections to... The close relationship between the structure,evolution,and resources environment of the South China Sea is a current research focus and also a focal point of our study.In this paper,we use regional seismic sections to analyze the relationship between seismic facies and the structure and tectonic evolution of the northeastern South China Sea and propose new points about the structure and the direction of block(land mass) motion.First,the tectonic features are clear and can be divided into five different structural units which are both linked and independent of each other.Second,it doesn't matter if the South China Sea basin pattern is extensional,weakly compressive,or strongly compressive,the regional tectonic stress field is unified.For the first time we find that two shallow subduction zones are recognized in the seismic profiles.All the tectonic blocks have accordion-fold-style structures,converging in the east,and the South China Sea exhibits different stages of basin development:growth, maturity,end,and termination.The block subduction and regional block dip directions are all aligned with the regional stress field. 展开更多
关键词 Sea-floor spreading SCS shallow subduction one way drifting extrusion metamorphism accordion-style seismic facies
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Bleeding duodenal hemangioma: Morphological changes and endoscopic mucosal resection 被引量:7
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作者 Noriko Nishiyama Hirohito Mori +4 位作者 Hideki Kobara Shintarou Fujihara Takako Nomura Mitsuyoshi Kobayashi Tsutomu Masaki 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第22期2872-2876,共5页
Recently, the development of endoscopic procedures has increased the availability of minimally invasive treatments; however, there have been few case reports of duodenal hemangioma treated by endoscopic mucosal resect... Recently, the development of endoscopic procedures has increased the availability of minimally invasive treatments; however, there have been few case reports of duodenal hemangioma treated by endoscopic mucosal resection. The present report describes a case of duodenal hemangioma that showed various endoscopic changes over time and was treated by endoscopic mucosal resection. An 80-year-old woman presented with tarry stools and a loss of appetite. An examination of her blood revealed severe anemia, and her hemoglobin level was 4.2 g/dL. An emergency upper gastrointestinal endoscopy was performed. A red, protrusive, semipedunculated tumor (approximately 20 mm in diameter) with spontaneous bleeding on its surface was found in the superior duodenal angle. Given the semipedunculated appearance of the tumor, it was suspected to be an epithelial tumor with a differential diagnosis of hyperplastic polyp. The biopsy results suggested a telangiectatic hemangioma. Because this lesion was considered to be responsible for her anemia, endoscopic mucosal resection was performed for diagnostic and treatment purposes after informed consent was obtained. A histopathological examination of the resected specimen revealed dilated and proliferated capillary lumens of various sizes, which confirmed the final diagnosis of duodenal hemangioma. Neither anemia nor tumor recurrence has been observed since the endoscopic mucosal resection (approximately 1 year). Duodenal hemangiomas can be treated endoscopically provided that sufficient consideration is given to all of the possible treatment strategies. Interestingly, duodenal hemangiomas show morphological changes that are influenced by various factors, such as mechanical stimuli. 展开更多
关键词 Duodenal hemangioma Endoscopic muco-sal resection Gastrointestinal bleeding Morphologicalchanges Capillary hemangioma
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