Hygroresponsive Torsional Yarns and Actuators Based on Cascade Amplification of the Deformation

Fiber-based hygroresponsive torsional actuators provide desirable merits, such as light weight and shapeability, for developing smart systems to harvest energy from moisture which is a ubiquitous natural resource. A key challenge in this development is to realize moisture-triggered actuation combining large actuation and rapid responses. Here, a multiscale design strategy is explored to create high-performance hygroresponsive torsional actuators consisting of chitosan and multiwalled carbon nanotubes (MWCNTs). The superior actuation performance arises from the synergism of contributing factors at different scales, including 1) MWNCTs accelerate the water transport in primary twisted fibers (PTFs), fostering the rotation of PTFs upon moisture stimuli; 2) in situ-formed hierarchically-assembled twists realize cascade amplification of moisture-triggered actuation. Specifically, PTFs are self-twisted to generate secondary helical yarns, that are subsequently over-twisted to yield tertiary coiled yarn. The resultant yarn actuator can reach a maximum rotation speed of 11 400 rpm in 5 s, output gravitational potential energy of 2.4 J kg⁻¹ and gravitational potential power of 0.053 W kg⁻¹ during contraction. This work represents the first design of fiber-based actuators by virtue of moisture-triggered in situ formation of yarns. The established principles of multiscale design will enable high-performance fiber-based hygroresponsive actuators toward advanced intelligent textile and soft robotics.     

基于布尔代数的海底管道风险评价方法研究与应用

根据目标管道的实际情况,将目标海底管道分为平台立管段、海域管段、人工岛登陆段3段,确定了第三方损坏、腐蚀、制造与施工缺陷、误操作4个一级风险因素,细化二级风险因素,建立了包含23个指标的风险评价指标体系.对指数和相加的方法进行改进,把各项风险分值进行归一化处理,量化至0～1之间,基于布尔代数,运用故障树的逻辑或原理,计算失效概率和泄漏影响系数,得到改进后的海底管道半定量风险评价模型,解决了传统模型中的风险值相加导致的风险遮蔽问题.     

La3+ 掺杂对 CeO2 红外发射性能的影响研究

随着飞行器飞行速度和发动机燃烧室温度的提高, 金属类隐身涂层材料已无法满足环境使用要求。 CeO2 具有较高熔点、 抗氧化、 较低红外发射率等特点, 被认为是红外隐身应用的候选材料, 但其发射率仍无法满足 高温红外隐身需求。 本文通过固相反应法对 CeO2 进行 La3+ 掺杂改性, 研究掺杂量对 CeO2 粉体红外发射性能的 影响规律。 结果表明, 随着掺杂量从 10 mol% 增加到 30 mol%, 粉体在 3~6 μm 波段的发射率不断降低, 其中 Ce0.7La0.3O2 的红外发射率仅为 0.1。     

YG1900超高强度钢性能指标离散机理分析及工艺改进

6t真空感应+6 t真空自耗双真空工艺冶炼+锻造成材工艺生产的Φ200 mm YG1900超高强度钢,在性能检测时发现性能指标有离散现象。本文对性能指标离散的试样显微组织进行扫描电镜及电子探针分析,结果表明:由于W、Mo偏析使组织中碳化物偏聚是导致性能指标离散的原因。将真空自耗冶炼熔速由4～5 kg/min降低到3～4 kg/min,锻造钢锭均质化温度由1 200～1 220℃提高到1 230～1 250℃,锻造生产总锻比由24～30增加到50～56,通过工艺改进后改善了YG1900超高强度钢性能指标离散问题。     

微型齿轮注射成型的模拟分析与试验研究

选用微型齿轮结构作为研究对象，在使用MoldFlow进行模拟分析的基础上．对微型齿轮注射成型进行试验研究。     

Effects of Austempering after Hot Deformation on the Mechanical Properties of Hot Rolled Si-Mn TRIP Steel Sheets

Excellent mechanical properties are obtained by austempering after hot deformation without subsequent heat treatment in the present Si-Mn TRIP steel sheets. Isothermal holding time after finishing rolling has affected the mechanical properties of this steel. The results show that the sample exhibits a good combination of ultimate tensile strength and total elongation when it is held at the bainite transformation temperature after hot deformation. The stability of retained austenite increases with an increase of isothermal holding time, and a further increase in the holding duration results in a decrease of it. The tensile strength, total elongation and strength ductility reach the maximum values (774MPa, 33% and 25542MPa% respectively) for this sort of hot rolled Si-Mn TRIP steel using the optimal technology.     

AZ91D热化学反应热喷涂陶瓷涂层耐蚀性研究

在镁合金AZ91D表面使用火焰喷涂制备陶瓷涂层，陶瓷涂层粉末配方为Al2O3＋TiO2＋SiO2＋ZnO＋Al。在喷涂制备涂层过程中伴随热化学反应的进行，涂层X射线分析发现，涂层内有MgSiO4、MgAl2O4等新相生成。耐蚀性试验表明，涂层的耐酸性能比基体提高了4倍，耐盐性能提高了1倍。     

等离子喷涂纳米Al2O3-13%TiO2涂层组织与性能

采用大气等离子喷涂方法制备了纳米结构Al2O3-13%TiO2(质量分数,下同)涂层,进行了SRV滑动磨损试验,通过扫描电镜对涂层的断口显微组织及磨损表面形貌进行了观察,并测定了涂层的显微硬度.结果表明,该纳米涂层具有独特的显微组织结构特征,层片间具有冶金结合特征的界面较多,界面结合得到明显改善,其显微硬度明显高于微米涂层,具有优良的耐磨性能,其磨损面积仅为常规微米涂层的1/5,界面结合改善是耐磨性提高的主要原因.     

镁渣膨胀性机理试验研究

通过镁渣形成过程、组成、粉化、颗粒分析和安定性试验,研究了镁渣产生体积膨胀性和膨胀滞后性的机理,提出了减轻或消除其膨胀性和膨胀滞后性危害的方法和措施,为镁渣在建筑、交通、水利等工程领域中的应用提供理论依据和指导。     

大型空分分子筛运行总结

本文介绍了我厂空分分子筛系统在原始试车及以后生产过程中出现的问题及解决办法。对分子筛的运行提出了一些看法。