The volume fractions and morphology of precipitates in precipitation-strengthened Cu-Ti alloys,which precipitate mainly as continuous and discontinuous precipitates,are important for the application of the alloy.This ...The volume fractions and morphology of precipitates in precipitation-strengthened Cu-Ti alloys,which precipitate mainly as continuous and discontinuous precipitates,are important for the application of the alloy.This study employed hardness and electrical conductivity tests transmission electron microscopy(TEM),atom probe tomography(APT),and first-principles calculations to demonstrate that the addition of Mg is effective for accelerating nanosized continuousβ'-Cu_(4)Ti precipitation as well as for suppressing the precipitation of coarse lamellar discontinuousβ-Cu_(4)Ti precipitates along the grain boundaries,resulting in Cu-Ti alloys with high yield strength and good electrical conductivity.The results showed that the continuous precipitation ofβ'-Cu_(4)Ti was accelerated by the Mg additions,which reduced the supersaturation of the matrix,thereby reducing the chemical driving force for the discontinuous precipitates.On the other hand,Mg additions increased the mismatch between the discontinuousβ-Cu_(4)Ti precipitates and matrix decreased the nucleation rate of the discontinuous precipitates,and increased the spacing of the discontinuous precipitation layer,resulting in a lower growth rate of the discontinuous precipitates.Therefore,the addition of Mg to Cu-Ti alloys enhances the strength and improves the resistance to over-ageing.展开更多
富血小板血浆(platelet-rich plasma,PRP)在骨科中的应用越来越受到重视,因其具有促进细胞增殖和损伤修复的作用,可为细胞的增殖、修复提供一个富含细胞因子和生长因子的微环境[1],此外,PRP中还富含巨噬细胞,有助于吞噬炎性介质,促进炎...富血小板血浆(platelet-rich plasma,PRP)在骨科中的应用越来越受到重视,因其具有促进细胞增殖和损伤修复的作用,可为细胞的增殖、修复提供一个富含细胞因子和生长因子的微环境[1],此外,PRP中还富含巨噬细胞,有助于吞噬炎性介质,促进炎症消散。发育性髋关节发育不良(developmental dysplasia of the hip,DDH)是临床常见的骨关节疾病,也是发生髋关节炎常见原因之一[2],如果治疗不及时或不当,随着年龄增大,病情加重,可出现严重髋关节脱位,影响患者的身心健康和生活质量[3]。CroweⅣ型DDH是最严重的一种DDH类型,可引起患者髋关节严重脱位,股骨头上移,导致形成假臼的骨关节炎,同时使周围软组织出现肌群挛缩、坐骨神经结构异常等情况出现,增加了手术治疗难度[4]。成人CroweⅣ型DDH患者髋关节旋转中心上移明显,肢体严重短缩,周围软组织明显挛缩,手术治疗原则首先要恢复髋关节正常的生物力学结构及髋关节正常的旋转中心,消除疼痛和跛行状态;若要达到这一点,必然需要股骨下移,也就导致了下肢的延长。常规THA常因过度牵拉下肢而导致下肢延长,可能造成周围神经及血管的损伤。研究发现,下肢延长4 cm以上坐骨神经损伤的风险将成倍增加,且周围软组织张力明显增高,会影响髋关节功能。因此,对于成人CroweⅣ型DDH患者,大部分学者提倡THA联合粗隆下截骨治疗[5]。而PRP疗法为促进CroweⅣ型DDH患者粗隆下横行截骨术后恢复的治疗带来了新思路,虽然目前大量的临床研究已经证实了PRP疗法对于骨关节、肌腱韧带软组织损伤的疗效,但少有研究探讨PRP对于CroweⅣ型DDH患者粗隆下横行截骨术后恢复的治疗效果。本篇报道了1例CroweⅣ型DDH患者使用PRP促进截骨术后恢复的案例。展开更多
基金financially supported by the Technological Innovation 2025&Major Special Project of Ningbo(Nos.2021Z084 and 2020Z039)。
文摘The volume fractions and morphology of precipitates in precipitation-strengthened Cu-Ti alloys,which precipitate mainly as continuous and discontinuous precipitates,are important for the application of the alloy.This study employed hardness and electrical conductivity tests transmission electron microscopy(TEM),atom probe tomography(APT),and first-principles calculations to demonstrate that the addition of Mg is effective for accelerating nanosized continuousβ'-Cu_(4)Ti precipitation as well as for suppressing the precipitation of coarse lamellar discontinuousβ-Cu_(4)Ti precipitates along the grain boundaries,resulting in Cu-Ti alloys with high yield strength and good electrical conductivity.The results showed that the continuous precipitation ofβ'-Cu_(4)Ti was accelerated by the Mg additions,which reduced the supersaturation of the matrix,thereby reducing the chemical driving force for the discontinuous precipitates.On the other hand,Mg additions increased the mismatch between the discontinuousβ-Cu_(4)Ti precipitates and matrix decreased the nucleation rate of the discontinuous precipitates,and increased the spacing of the discontinuous precipitation layer,resulting in a lower growth rate of the discontinuous precipitates.Therefore,the addition of Mg to Cu-Ti alloys enhances the strength and improves the resistance to over-ageing.
文摘富血小板血浆(platelet-rich plasma,PRP)在骨科中的应用越来越受到重视,因其具有促进细胞增殖和损伤修复的作用,可为细胞的增殖、修复提供一个富含细胞因子和生长因子的微环境[1],此外,PRP中还富含巨噬细胞,有助于吞噬炎性介质,促进炎症消散。发育性髋关节发育不良(developmental dysplasia of the hip,DDH)是临床常见的骨关节疾病,也是发生髋关节炎常见原因之一[2],如果治疗不及时或不当,随着年龄增大,病情加重,可出现严重髋关节脱位,影响患者的身心健康和生活质量[3]。CroweⅣ型DDH是最严重的一种DDH类型,可引起患者髋关节严重脱位,股骨头上移,导致形成假臼的骨关节炎,同时使周围软组织出现肌群挛缩、坐骨神经结构异常等情况出现,增加了手术治疗难度[4]。成人CroweⅣ型DDH患者髋关节旋转中心上移明显,肢体严重短缩,周围软组织明显挛缩,手术治疗原则首先要恢复髋关节正常的生物力学结构及髋关节正常的旋转中心,消除疼痛和跛行状态;若要达到这一点,必然需要股骨下移,也就导致了下肢的延长。常规THA常因过度牵拉下肢而导致下肢延长,可能造成周围神经及血管的损伤。研究发现,下肢延长4 cm以上坐骨神经损伤的风险将成倍增加,且周围软组织张力明显增高,会影响髋关节功能。因此,对于成人CroweⅣ型DDH患者,大部分学者提倡THA联合粗隆下截骨治疗[5]。而PRP疗法为促进CroweⅣ型DDH患者粗隆下横行截骨术后恢复的治疗带来了新思路,虽然目前大量的临床研究已经证实了PRP疗法对于骨关节、肌腱韧带软组织损伤的疗效,但少有研究探讨PRP对于CroweⅣ型DDH患者粗隆下横行截骨术后恢复的治疗效果。本篇报道了1例CroweⅣ型DDH患者使用PRP促进截骨术后恢复的案例。
