| 1 | Determination of stress intensity factor with direct stress approach using finite element analysis显示文摘In this article, a direct stress approach based on finite element analysis to determine the stress intensity factor is improved. Firstly, by comparing the rigorous solution against the asymptotic solution for a problem of an infinite plate embedded a central crack, we found that the stresses in a restrictive interval near the crack tip given by the rigorous solution can be used to determine the stress intensity factor, which is nearly equal to the stress intensity factor given by the asymptotic solution. Secondly, the crack problem is solved numerically by the finite element method. Depending on the modeling capability of the software, we designed an adaptive mesh model to simulate the stress singularity. Thus,the stress result in an appropriate interval near the crack tip is fairly approximated to the rigorous solution of the corresponding crack problem. Therefore, the stress intensity factor may be calculated from the stress distribution in the appropriate interval, with a high accuracy. | X.Ji F.Zhu P.F.He | 2017 | Acta Mechanica Sinica2017，33，5： | 3 |
| 3 | 基于磁敏感的磁兼容金属植入物的正对比磁共振成像显示文摘在磁共振成像中,磁共振兼容金属植入物的磁化率较高,从而导致图像信号的缺失与失真,严重影响装置的精准定位和评估。2014年,有学者提出一种正对比成像方法,利用偏移180°回聚脉冲的自旋回波序列,结合特有的定量磁化率重建算法,重建出近距离放射颗粒的正对比图像。在此基础上,文章对该方法进行进一步扩展,在西门子3 T人体磁共振成像系统上,将该方法应用到活检针和过滤器等较大金属介入装置的正对比成像。活检针和过滤器水模磁共振成像实验结果表明,这种正对比成像方法可应用于较大的金属装置,有效地抑制了金属伪影,获得清晰的正对比图像,提高了装置定位和评估的精准度。 | 陈敏 史彩云 苏适 张晓咏 Jim X.Ji Ying Dong 刘新 谢国喜 | 2016 | 集成技术2016，5，3： | 0 |
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