韧带-骨支架仿生界面设计与制造方法

针对当前软质韧带支架与硬质骨组织通过机械固定进行韧带修复存在的应力集中与疲劳断裂问题,提出了具有仿生界面的韧带-骨支架设计与制造方法。研究了自然韧带-骨界面的微观结构,通过工程简化设计了具有仿生界面的韧带-骨复合支架,提出了韧带-骨支架仿生界面的分层制造方法,从材料、力学及微观结构方面对所制备的韧带-骨支架仿生界面进行了分析评价。结果表明,所提出的分层制造方法可在软质韧带纤维支架与硬质陶瓷骨支架之间精确制造出所设计的仿生界面,其在材料成分、力学性能及微观结构上呈现分区变化特性。后期通过骨支架与自体骨融合生长以及仿生界面的多组织再生,有望实现韧带纤维支架与自体骨骨道的生理愈合及可靠固定,从而为临床韧带修复提供一种新思路。     

天然丝素制备三维多孔支架

研究盐沥滤法制备三维多孔丝素支架,在丝素多孔支架上培养人成骨肉瘤细胞、成纤维细胞及肝细胞.研究材料的细胞相容性,发现多种动物细胞在盐沥滤法所制备的丝素多孔支架材料上能够很好地黏附和增殖.通过调整丝素水溶液的浓度、溶解丝素溶剂体系、NaCl添加量和NaCl粒径,制备出结构和性质可以调控的三维支架.该结果为丝素多孔支架材料的制备提供了新的研究思路和方法.     

Effect of degradation of PLGA and PLGA/β-TCP scaffolds on the growth of osteoblasts

Osteoblasts were cultured on porous scaffolds of poly(L-lactide-co-glycolide) (PLGA) and PLGA/β-tricalcium phosphate (β-TCP) to evaluate their cytocompatibility. The proliferation of the cells on both scaffolds was examined before and after in vitro degradation for 4, 8 and 12 weeks under static (shaking water bath) and dynamic (cyclic loading) conditions. Results indicate that porous PLGA and PLGA/β-TCP scaffolds have good biocompatibility and can be used as effective templates for guiding the growth of osteoblasts. The degradation of the scaffolds affects the proliferation of osteoblasts and the cell viability decreased with the degradation time.     

梢涡对拍动平板升力性能的影响

采用有限体积法求解黏性Navier-Stokes方程,以动网格方法基于弹簧变形原理结合拉普拉斯网格重绘方法光顺网格,分析了Re=100时2-D、3-D拍动平板的升力、阻力性能以及尾流场,并采用并行计算求解3-D问题以节省计算时间.通过计算旋转同步、滞后2种拍动模式下平板升力性能,以及拍板运动过程中流场压力分布的变化,探讨梢涡对拍板升力性能的影响.计算结果表明,在旋转滞后模式下梢涡使拍板的升力系数有较大增加,而旋转同步模式下仅使拍板的升力系数稍有增加,说明梢涡对拍板升力性能的影响与拍板运动参数有重要关系.     

虚拟仪器在数据采集中的应用

本文简要介绍了虚拟仪器的概念和虚拟仪器的体系结构,然后对半图形化的开发工具LabWindows/CVI编程语言进行了介绍,分析了软件开发工具LabWindows/CVI的开发流程,并结合电动车窗防夹测试系统的实验结果,说明了使用虚拟仪器开发可以获得优良的测试性能。     

肝组织工程支架的仿生设计与有限元分析

为了解决细胞在细胞支架复合培养中难以植入的问题,提出了一种卷裹型支架.将平面多孔支架采用卷裹的方式成型,使细胞在整个支架内部形成螺旋状三维分布,支架表面的管道结构可使培养液在支架内部渗透,从而提高物质交换效率.提出了一种具有仿生参数的流道设计方案,从肝脏血管铸型中提取血管的形状数据,作为仿生学依据进行流道设计,具体为树状多层分支结构.用此流道结构仿生了动脉、静脉的血液循环功能,并利用多孔材料仿生了毛细血管的渗透功能.建立了不同形状参数的流场分析模型,进行流体与多孔材料的渗流分析.结果表明,仿生设计方案的流场分布最为均匀,且平均流速较高,间接表明营养物质的输送效率最高.该支架能够使细胞呈三维分布,并扩大培养液在支架内的有效分布范围,更好地维持细胞的存活、增殖和迁移,为向组织化方向发展奠定了一定的基础.     

小型叉车货叉的ISO设计

叉车货叉在贯彻执行 ISO 国际标准的基础上,确定了以1.5吨货叉为代表的小型叉车货叉的基本参数和尺寸,进行了货叉的强度验算和刚度校核,并对货叉挂钩的型式、结构特点、规范化尺寸和焊接强度等问题作了说明或计算.     

对自行车运动员踏蹬技术的探讨

本文从力学和形态学的角度,根据自行车足踏蹬一周圆周运动的受力情况,进行踏蹬技术特征的分析研究,试图解释运动员正确踏蹬骑行动作的科学原理。     

3D Nanocomposite Hydrogel Scaffolds Fabricated by Rapid Prototyping for Bone Tissue Engineering

Colloidal gels made of oppositely charged nanoparticles are a novel class of hydrogels and can exhibit pseudoplastic behavior which will enable them to mold easily into specific shapes. These moldable gels can be used as building blocks to self-assemble into integral scaffolds from bottom to up through electrostatic forces. However, they are too weak to maintain scaffold morphology just depending on interparticle interactions such as Van der Waals attraction and electrostatic forces especially for bone tissue engineering. In this study, oppositely charged gelatin nanoparticles were firstly prepared by two-step desolvation method, followed by the mixture with water to form colloid gels. To solve the problem of weak mechanical performance of colloid gels, gelatin macromolecules were introduced into the prepared gels to form blend gels. The blend gels can be easily processed into three-dimensional （3D） porous scaffolds via motor assisted microsyringe （MAM） system, a nozzle-based rapid prototyping technology, under mild conditions. After fabrication the scaffolds were erosslinked by glutaraldehyde （ GA, 25 % solution in water by weight）, then the crosslinked gelatin macromolecules network could form to improve the mechanical properties of colloid gels. The average particle size and zeta potential of gdatin nanoparticles were measured by Nano- ZS instrument. The morphology and microstructures of scaffolds were characterized by macroscopic images. The mechanical properties of the scaffolds were studied by a universal material testing machine.     

错列双圆柱下游圆柱的升力机理

采用大涡模拟(LES)的方法,在雷诺数Re=1.4×10~5时,研究了间距P/D=4(P为圆心间距,D为圆柱直径)、风向角0°～90°的错列双圆柱的气动力特性和干扰流态,从流场角度分析了下游圆柱受到平均升力和脉动升力作用的流场机理.结果表明:随着风向角的增大,两个圆柱的干扰流态依次为旋涡撞击流态、旋涡撞击和剪切层干扰流态、剪切层干扰流态、尾流干扰流态;在旋涡撞击流态、旋涡撞击和剪切层干扰流态下,上游圆柱的旋涡与下游圆柱发生强烈的撞击,导致下游圆柱的脉动升力远大于单圆柱;在剪切层干扰流态下,下游圆柱受到显著的平均升力作用,下游圆柱风压停滞点的偏移以及上游圆柱的旋涡与下游圆柱间隙侧剪切层(或旋涡)的相互作用,是下游圆柱受到平均升力作用的两个原因.