立交桥施工中WDJ钢管脚手架的受力分析

在立交桥、高架桥和人行天桥的建设过程中，作为施工模板支撑的脚手架搭设常遇到承载力不足，脚手架失稳等问题，根据现浇钢筋混凝土立交桥施工过程中此类脚手架的搭设情况，以实际工程中常用的WDJ碗扣式钢管脚手架为对象，运用有限元程序ANSYS进行分析，着重研究桥梁腹板位置变化、桥梁高度变化对脚手架受力的影响，同时对风荷载作用下的脚手架和隔梁位置下的脚手架进行受力分析，提出通常情况下WDJ碗扣式钢管脚手架的选用形式，为脚手架工程的安全施工提供一定的帮助。     

附着升降脚手架的应用分析

介绍了附着升降脚手架应用及分类、特点；并对整体爬升脚手架构造、安全、经济进行了综合分析，认为附着升降脚手架即能满足施工要求，又可节省费用，是一种新型、实用的脚手架施工方法。     

电梯无脚手架安装工艺

电梯是随着高层建筑的兴建而发展起来的一种垂直运输工具，在电梯的安装过程中，常规的施工工艺是先搭设井道脚手架，然后进行设备安装，在电梯安装过程中得到普遍应用，但在高层电梯安装时，有脚手架电梯安装缺点就暴露出来了。所以随着高层建筑越来越多的出现，传统的有脚手架安装，程序复杂而且费时，为了更加有效、快捷地安装电梯，电梯的无脚手架安装工艺就出现了，它能够更加适应高层建筑电梯安装的需要。本文根据现在电梯安装的特点和实际需求，并依据本人平时现场检验中遇到的情况，就电梯无脚手架安装工艺以及此工艺的优缺点进行阐述，并提出在无脚手架安装电梯时应当避免出现的问题。     

型钢悬挑扣件式钢管脚手架设计与安装

高层建筑施工用脚手架工程中往往离不开悬挑结构用来分担荷载。或者因建筑物设计需要而必须采用悬挑脚手架。本文结合工程实例介绍型钢悬挑扣件式钢管脚手架设计与安装，为施工生产提供符合安全使用要求的脚手架。     

建筑施工脚手架事故的预防和控制．

建筑行业既是高危行业又是事故多发行业。近年来，随着建设规模的逐年扩大，建筑施工中发生的伤亡事故和死亡人数也有所上升，其中由脚手架问题造成的群死群伤事故尤为频发。针对脚手架安全事故发生的原因，积极采取科学合理的预防措施，对减少脚手架安全事故的频发、多发至关重要。     

论导座式升降脚手架选用及施工要点

简要介绍了高层建筑施工中的导座式升降脚手架的功能、形式、特点及工程应用，并结合南昌市某高层建筑的脚手架的施工，介绍了导座式升降脚手架的方案选择、施工工艺、架体的构造及安全措施，供广大工程技术人员参考。     

电梯无脚手架安装工艺探讨及优化

本文介绍了电梯无脚手架安装技术的指标要求，对电梯无脚手架安装工艺进行了探讨。     

房建项目扣件式模板支架安全性探讨之稳定性分析

0．引言 扣件式钢管脚手架是目前我国使用最为广泛的一种外墙脚手架、模板支架搭设方式，在今后可预见的较长一段时间内，仍将得到大量采用。相对毛竹木脚手架而言，虽然其安全性、重复使用次数均有较大提高，但仍存在构造较为复杂、施工工效较低等缺点，成为现场安全事故防范中的重点和难点。据建设部2009年3级以上重大事故统计，脚手架坍塌事故就占总事故数的60．87％，死亡人数则占67．62％，尤其是扣件式钢管承重支架，发生事故的比率更高。     

门式脚手架的搭设构造及设计计算

文章运用弹性稳定理论的有限元法．探讨了门式钢管脚手架各种搭设状态下的实际受力性能，分析了影响脚手架承载力的各主要因素．文中还提出了承受非比例荷载的结构稳定计算新方法。通过计算表明，所提出的计算方法对门式钢管脚手架的设计计算有实用价值。     

悬挑型钢外脚手架在高层建筑施工中的控制要点

结合某学术交流中心工程悬挑型钢外脚手架搭设方面的实践，对悬挑型钢外脚手架在高层建筑施工中的控制要点进行总结。     

Fabrication and characterization of electrospun poly-L-lactide/gelatin graded tubular scaffolds: Toward a new design for performance enhancement in vascular tissue engineering

In this study, a new design of graded tubular scaffolds have been developed for the performance enhancement in vascular tissue engineering. The graded poly-L-lactide (PLLA) and gelatin fibrous scaffolds produced by electrospining were then characterized. The morphology, degradability, porosity, pore size and mechanical properties of four tubular scaffolds (graded PLLA/gelatin, layered PLLA/gelatin, PLLA and gelatin scaffolds) have been investigated. The tensile tests demonstrated that the mechanical strength and also the estimated burst pressure of the graded scaffolds were significantly increased in comparison with the layered and gelatin scaffolds. This new design, resulting in an increase in the mechanical properties, suggested the widespread use of these scaffolds in vascular tissue engineering in order to prepare more strengthened vessels.     

Preparation of PLGA-collagen hybrid scaffolds with controlled pore structures for cartilage tissue engineering

Scaffolds used for cartilage tissue engineering should have high mechanical strength and well-controlled pore structure to provide suitable microenvironments for functional tissue regeneration. In this study, hybrid scaffolds which had open and interconnected pore structure and high mechanical property were prepared by hybridization of PLGA mesh and collagen using ice particulates as porogen templates. Embossing ice particulates template was used to form open pore structures on the scaffold surfaces. Free ice particulates were used to generate interconnected bulk pores in the scaffolds. Hybridization with PLGA mesh provided the scaffolds with high mechanical property. Bovine articular chondrocytes were cultured in the hybrid scaffolds. The unique pore structures facilitated the homogeneous distribution of chondrocytes and cartilaginous matrices throughout the scaffolds. Subcutaneous implantation demonstrated cartilage-like tissue regeneration. The hybrid scaffolds should have a high potential for cartilage tissue engineering.     

Preparation of 3-D porous fibroin scaffolds by freeze drying with treatment of methanol solutions

In this study, silk scaffolds with appropriate porous structures were prepared by adjusting solution concentrations and providing treatment with methanol solutions in the way of freeze drying. The effects of the preparation conditions on the microstructures and properties of the scaffolds were discussed. Fibroin solutions with different concentrations of 4, 6, 8, 10 wt% were used respectively to prepare the scaffolds. The effects of the addition of 20 vol% methanol before or after freeze drying to the 4 wt% fibroin solution were investigated. As demonstrated by Scanning Electron Microscope (SEM), the fib-roin scaffolds prepared without methanol had porous microstructures composed of thin sheets, and the sizes of the pores decreased with the increase of the fibroin solution concentrations, while the scaffolds prepared in the presence of methanol showed porous microstructures formed by fine-particle aggregates. The porosities and mechanical properties of the prepared fibroin scaffolds under different conditions were tested. The crystalline structures and conformations of the fibroin scaffolds were detected by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).     

用于软骨下骨修复的镁基支架

骨关节炎（osteoarthritis,OA）作为一种可以导致残疾的退行性疾病,常累及软骨下骨。受损的关节软骨和软骨下骨很难自愈,用于功能修复的组织工程支架是一种有前途的治疗方法。近年来,镁合金因其良好的机械和生物学性能被视为可降解多孔支架有希望的候选者。然而,目前对于适用于软骨下骨缺损修复的镁基支架的结构设计和优化方案还没有定论。归纳了镁合金用于骨软骨支架的研究进展,包括多孔支架的制造方法;添加合金元素和表面改性的优化策略;参数化与非参数化的结构设计;镁基支架的机械、降解和生物学性能及其影响因素。讨论了未来研究的潜在方向。旨在为多孔镁基支架的开发和临床应用提供参考。     

Towards a Medium/High Load-Bearing Scaffold Fabrication System

This paper describes fabrication of scaffolds for load-bearing applications, with primary consideration from the manufacturing perspective. An extrusion device, inspired by the FDM process, was used to create scaffolds from a variety of different polymeric materials and mixtures. The effectiveness of these scaffolds to host cells for bone regeneration has been investigated. This ongoing work has generated significant insight into the future direction of research and the possibilities of developing scaffolds for medium/high load-bearing applications.     

骨组织工程聚左旋乳酸多孔框架快速成形研究

为制备用于骨组织工程的细胞载体框架结构 ,对快速成形技术制备聚左旋乳酸多孔框架结构的若干基础问题进行了研究。提出了聚左旋乳酸快速成形的精密挤出成形工艺 ,研究了此工艺制备多孔框架结构的设备与工艺过程 ,分析了制备的多孔框架结构应用于组织工程人工骨的可行性。制备的多孔框架结构具有合适的分子量、孔隙结构、孔隙率、机械强度和生物降解性能 ,可以用作骨组织工程的组织再生框架结构     

聚氨酯改性及复合支架应用于血管组织工程

通过查阅近年来将聚氨酯作为血管组织工程支架材料的相关文献,介绍了聚氯酯改性的常用方法在血管组织工程支架中的应用情况,综述了聚氨酯表面改性支架和复合支架在血管组织工程中的应用.     

可降解聚醚酯弹性体PTCG的合成及初步生物学评价

用熔融缩聚法合成聚对苯二甲酸丁二醇酯-co-聚对苯二甲酸环己烷二甲醇酯-b-聚乙二醇(PTCG)聚醚酯弹性体.按照ISO 10993标准,采用L929小鼠成纤细胞对其进行体外细胞毒性测试;以狗的血管平滑肌细胞 (SMCs)为模板细胞,测试细胞在材料表面的贴附性能.采用旋转成型/粒子洗出法制备三维血管支架,接种SMCs后在生物反应器上进行动态培养,探索PTCG作为组织工程血管支架材料的可行性.结果表明,合成的PTCG聚醚酯弹性体无细胞毒性;SMCs在PTCG薄膜表面贴附生长良好;所制备支架的孔径、孔隙率和力学性能等满足组织工程血管支架的要求;体外培养3 d后,大量SMCs长入血管支架并开始分化.     

纳米支架在组织工程中的研究进展

纳米纤维支架技术是组织工程中为了支持细胞形成受损组织生物替代物的新兴技术。纳米支架能模拟天然的细胞外基质,作为三维的模板供细胞吸附、增殖以及分化。主要介绍了纳米纤维支架的结构特性、构建技术以及生物学效应。     

Effects of Quenching Temperature and Time on Pore Diameter of Poly（3-hydroxybutyrate-co-3-hydroxyhexanoate） Porous Scaffolds and MC3T3-E1 Osteoblast Response to the Scaffolds

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) scaffolds were prepared by thermally inducing phase separation (TIPS) for bone reconstruction. Scanning electron microscopy and porosity measurements were used to analyze the structure and properties of the scaffolds. The pore diameter of the scaffolds could be easily controlled by changing the quenching temperature and time. The biocompatibility was assessed by examining the proliferation and morphology of MC 3T3-E1 osteoprogenitor cells seeded on the scaffolds. Cultures grown in the presence of a source of phosphate ions showed the formation of a mineralized extracellular matrix. The results indicate that PHBHHx scaffolds prepared using TIPS are a promising candidate for bone reconstruction.