磨料水射流除鳞生产线中圆钢旋转机的设计

为了有效实施磨料水射流对圆钢的除鳞,提出了设计圆钢旋转机的构想,并从多种方案中选择了带旋转辊的方案。实践表明,按该方案设计的旋转机其工作正常,效果良好。     

Light-Responsive Programmable Shape-Memory Soft Actuator Based on Liquid Crystalline Polymer/Polyurethane Network

Liquid crystalline polymers (LCPs), especially liquid crystalline elastomers (LCEs) can generate ultrahigh shape change amplitude but has lower mechanical strength. Although some attempts have been tried to improve the mechanical performance of LCE, there are still limitations including complicated fabrication and high actuation temperature. Here, a versatile method is reported to fabricate light-driven actuator by covalently cross-linking polyurethane (PU) into LCP networks (PULCN). This new scheme is distinct from the previous interpenetrating network strategy, the hydrogen bonds and covalent bonds are used in this study to improve the miscibility of non-liquid-crystalline PU and LCP materials and enhance the stability of the composite system. This material not only possesses the shape memory properties of PU but shows shape-changing behavior of LCPs. With a shrinkage ratio of 20% at the phase transition temperature, the prepared materials reached a maximum mechanical strength of 20 MPa, higher than conventional LCP. Meanwhile, the resulting film shows diverse and programmable initial shapes by constructing crosslinking density gradient across the thickness of the film. By integration of PULCN with near-infrared light-responsive polydopamine, local and sequential light control is achieved. This study may provide a new route for the fabrication of programmable and mechanically robust light-driven soft actuator.     

鱼雷滚轮斜置式凸轮发动机分析

为了深入研究鱼雷滚轮斜置式凸轮发动机的工作机理,推导了求取该类发动机凸轮接触点参数的方法,对其凸轮与滚轮之间的作用力以及凸轮转矩做了初步分析,并将该类发动机与传统非斜置式发动机进行了比较。比较分析结果表明,滚轮斜置式结构有利于提高凸轮发动机的性能。     

国产双辊热轧机

国产双辊热轧机的性能优良,工作可靠;轧制的非织造布强力高,柔软度和手感好,达到了国外同类产品的质量指标,得到用户的认可和好评.该机适用于纺粘法聚丙烯非织造布和聚酯短纤维热轧非织造布的生产。本文介绍了该机的工作原理、结构特点、使用情况及其取得的经济效益。     

SC系列涂饰剂的性能特点及应用

对聚氨酯涂饰剂系列产品的性能特点及应用进行了阐述。 Ｓ Ｃ９３００ 系列柔软性突出,遮盖力强; Ｓ Ｃ９６０ 系列丰满弹性显著,遮盖力好,耐溶剂; Ｓ Ｃ８００ 系列涂层薄,真皮感强,弹性好,耐溶剂,耐水性好。合理搭配使用,能满足不同革品种的涂饰要求。提供１０ 个分别用于大面积补伤、服装革、沙发革、鞋面革涂饰的配方及工艺供参考。     

空调滑片式压缩机用圆柱滚子轴承摩擦功耗特性分析

为了降低空调滑片式压缩机的摩擦功耗,对其所用圆柱滚子轴承的摩擦功耗特性进行了研究。基于滚动轴承动力学理论,考虑周期性载荷因素,建立了压缩机用圆柱滚子摩擦功耗数学模型,在此基础上分析了轴承工况参数和结构参数对圆柱滚子轴承摩擦功耗特性的影响规律。研究结果表明：在满足轴承使用要求前提下,选取较大的径向游隙有利于降低轴承的摩擦功耗;圆柱滚子轴承存在合理的保持架引导间隙和保持架兜孔间隙,使得轴承摩擦功耗最小;随着滚子个数增加,轴承摩擦功耗增加,在保证轴承承载能力前提下,可以适量减少滚子数量,以降低轴承摩擦功耗;新型滑片式压缩机摩擦功耗比传统型降低了39%.     

汽车发动机皮带轮表面缺陷原因分析

某汽车发动机皮带轮在加工过程中,近50%的零件表面发现有微裂纹。用金相显微镜、扫描电镜和超声波C扫描等分析仪器,研究汽车发动机皮带轮表面缺陷的形成原因。结果表明,零件表面的缺陷是钢管原材料在冶炼浇注过程中混入的硅酸盐类粗夹杂形成的。     

A Biologically Muscle-Inspired Polyurethane with Super-Tough,Thermal Reparable and Self-Healing Capabilities for Stretchable Electronics

Polymeric elastomers play an increasingly important role in the development of stretchable electronics. A highly demanded elastic matrix is preferred to own not only excellent mechanical properties, but also additional features like high toughness and fast self-healing. Here, a polyurethane (DA-PU) is synthesized with donor and acceptor groups alternately distributed along the main chain to achieve both intra-chain and inter-chain donor-acceptor self-assembly, which endow the polyurethane with toughness, self-healing, and, more interestingly, thermal repair, like human muscle. In detail, DA-PU exhibits an amazing mechanical performance with elongation at break of 1900% and toughness of 175.9 MJ m⁻³. Moreover, it shows remarkable anti-fatigue and anti-stress relaxation properties as manifested by cyclic tensile and stress relaxation tests, respectively. Even in case of large strain deformation or long-time stretch, it can almost completely restore to original length by thermal repair at 60 °C in 60 s. The self-healing speed of DA-PU is gradually enhanced with the increasing temperature, and can be 1.0–6.15 µm min⁻¹ from 60 to 80 °C. At last, a stretchable and self-healable capacitive sensor is constructed and evaluated to prove that DA-PU matrix can ensure the stability of electronics even after critical deformation and cut off.     

对数螺旋线型面单向滚子离合器参数化设计

针对某对数螺旋线型面单向滚子离合器,进行了参数化设计的研究,提出了该型离合器参数化设计的一般原则,对其参数的设置进行了探讨;基于Pro/E的二次开发技术,编制了参数化的单向滚子离合器自动设计程序.该程序具有自动获取离合器参数、模型再生、自动生成工程图等功能,提高了产品设计的效率.