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RISS 인기검색어
- 검색키워드
- 저자 : Chong-Gang Ren (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
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Effect of single-pulse laser irradiation energy on healing fatigue damage for copper film
Chong-Gang Ren,De-Guang Shang,Lu Wang,Yu-Bo Guo 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4
In this study, the optimum laser process parameter was determined by fatigue experiment for the treated copper film specimens withthickness of 25 μm. The mechanism of healing fatigue damage was analyzed by the numerical simulation of temperature field induced bylaser irradiation and the microstructure changes on the surface of specimens. The results showed that the fatigue damage of copper filmspecimens can be healed when the applied energy density is in the range from 4×10³J/m² to14×10³ J/m², and the fatigue life can increaseby about 5 times when the applied energy density is 7×10³ J/m². The process hardening and grain refinement in the surface layer aremainly responsible for extending fatigue life.
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Lu-Ping Zhou,Jin Shang,Zhi-Gang Zhang,Zhen-Fei Jiang,Hua-Qing Zhang,Chong-Yu Jia,Ren-Jie Zhang,Cai-Liang Shen 대한척추신경외과학회 2022 Neurospine Vol.19 No.4
Objective: Patients with basilar invagination (BI) had high incidences of vertebral variations and high-riding vertebral artery (HRVA) that might restrict the use of pedicle or pars screw and increase the use of translaminar screw on axis. Here, we conducted a radiographic study to investigate the feasibility of translaminar screws and the bone quality of C2 laminae in patients with BI, which were compared with those without BI as control to provide guidelines for safe placement. Methods: In this study, a total of 410 patients (205 consecutive patients with BI and 205 matched patients without BI) and 820 unilateral laminae of the axis were included at a 1:1 ratio. Comparisons with regard to insertion parameters (laminar length, thickness, angle, and height) for C2 translaminar screw placement and Hounsfield unit (HU) values for the assessment of the appropriate bone mineral density of C2 laminae between BI and control groups were performed. Besides, the subgroup analyses based on the Goel A and B classification of BI, HRVA, atlas occipitalization, and C2/3 assimilation were also carried out. Furthermore, the factors that might affect the insertion parameters and HU values were explored through multiple linear regression analyses. Results: The BI group showed a significantly smaller laminar length, thickness, height, and HU value than the control group, whereas no significant difference was observed regarding the laminar angle. By contrast, the control group showed significantly higher rates of acceptability for unilateral and bilateral translaminar screw fixations than the BI group. Subgroup analyses showed that the classification of Goel A and B, HRVA, atlas occipitalization, and C2/3 assimilation affected the insertion parameters except the HU values. Multiple linear regression indicated that the laminar length was significantly associated with the male gender (B = 0.190, p < 0.001), diagnoses of HRVA (B = -0.109, p < 0.001), Goel A (B = -0.167, p < 0.001), and C2/3 assimilation (B = -0.079, p = 0.029); the laminar thickness was significantly associated with the male gender (B = 0.353, p < 0.001), diagnoses of HRVA (B = -0.430, p < 0.001), Goel B (B = -0.249, p = 0.026), and distance from the top of odontoid to the Chamberlain line (B = -0.025, p = 0.003); laminar HU values were significantly associated with age (B = -2.517, p < 0.001), Goel A (B = -44.205, p < 0.001), Goel B (B = -25.704, p = 0.014), and laminar thickness (B = -11.706, p = 0.001). Conclusion: Patients with BI had narrower and smaller laminae with lower HU values and lower unilateral and bilateral acceptability for translaminar screws than patients without BI. Preoperative 3-dimensional computed tomography (CT) and CT angiography were needed for BI patients.
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