新型有机玻璃在站台门的应用及有限元分析

介绍了新型有机玻璃的性能,通过对有机玻璃的相关性能进行分析,确认有机玻璃在站台门系统应用的可行性,为站台门节能减重的设计提供相关依据。     

AlB12-AlB12C2-TiB2 hard and tough composites synthesized by reactive plasma activated sintering

AlB₁₂-AlB₁₂C₂-TiB₂-based hard and tough composites were fabricated using ball milled B, Al, and Ti powders as the starting materials, and sintered by reactive plasma activated sintering (PAS). The mechanical properties and microstructures were investigated, and the effects of the composition and microstructures on the reinforcing and toughening of the composites were determined. The results showed that the composite with 10 vol% TiB₂ showed excellent mechanical properties, a lightweight of 2.76 g cm⁻³, Vickers hardness of 37 GPa, and fracture toughness of 7.1 MPa m^1/2. In addition, the main strengthening and toughening mechanisms were due to the twin structures, dislocation defects, and stacking faults in the specimen in addition to grain pull-out, crack deflection, crack bridging, and crack branching caused by elongated TiB₂ particles.     

Fast Directional Handoff and lightweight retransmission protocol for enhancing multimedia quality in indoor WLANs

More and more mobile devices such as smartphones are being used with IEEE 802.11 wireless LANs (WLANs or Wi-Fi). However, mobile users are still experiencing poor service quality on the move due to the large handoff delay and packet loss problem. In order to reduce the delay, a new handoff scheme using the geomagnetic sensor embedded in mobile devices is proposed in this paper. The proposed scheme predicts the movement direction of a Mobile Station (MS) from the currently associated Access Point (AP) and performs active scanning with a reduced number of channels. In terms of the packet loss, a lightweight retransmission protocol is also proposed to minimize lost packets on Wi-Fi without producing a lot of acknowledgement packets. The proposed approaches are implemented on Android smartphones, and their performance is evaluated in a real indoor WLAN environment. The evaluation results demonstrate that the proposed schemes maintain seamless quality for real-time video even in an environment with frequent handoffs. Note that the proposed schemes are a client-only solution and do not require modification of the existing APs, which renders them very practical.     

PZT components derived from polysulphone spinning process

The present paper deals with the development of lead zirconate titanate (PZT) fibres, pearls and fibre fragments, for their use as active phase in piezocomposites. As new a approach, the green ceramic components are shaped by polysulphone spinning, allowing for effective and flexible forming over a wide range of different geometries and sizes. The correlation between processing parameters, e.g. the slurry composition, nozzle size and operation velocity, and the resultant shape of ceramic components is analysed. Sintered piezoceramic parts show a dense microstructure. Performance data are evaluated on PZT/epoxy composites. Measurement results of strain, polarisation and piezoelectric coupling are given and discussed. The developed PZT components are seen as key for the creation of smart and lightweight structural components. Further, free formed PZT components open new design approaches for sensing and actuating devices and ultrasound transducers.     

汽车主模型ABS轻量化后地板检测模块的设计制造研究

后地板检测模块在燃油车与电动车内饰切换时拆卸频繁,为操作方便,需将后地板模块轻量化。而传统铝制模块密度大,质量易超标,因此,有必要采用轻量化材料如丙烯腈-丁二烯-苯乙烯共聚物(ABS)塑料来制备后地板检测模块。ABS材料密度小,成本低,但硬度低,强度弱,表面光洁度差。为解决这些问题,采用铝制骨架与ABS模块喷漆相结合的设计方式,通过设计阶段的强度计算,确定了质量轻、强度与表面质量均满足要求的后地板检测模块的设计方法。     

From magnesite directly to lightweight closed-pore MgO ceramics: The role of Si and Si/SiC

Partial/full replacement of traditional dense refractory aggregates (for furnace lining) with lightweight aggregates is considered to be an effective and promising strategy for energy saving and emission reduction. In this work, lightweight magnesia refractory ceramics with tailored closed porosity were prepared by one-step sintering at 1600 °C from high-purity magnesite added with silicon kerf waste in different ratios, with the emphasis on the evolution of their phase compositions, micromorphologies, and various properties. With the addition of additives, Mg_2–xFe_xSiO₄ solid solution was formed at the grain boundaries of the MgO matrix, and then the volumetric expansion effect (interfacial reaction) and activated sintering effect (vacancy defect) promote the decrease of apparent porosity and the increase of closed porosity, respectively. Consequently, MgO ceramics with apparent/closed porosity of 0.6%/6.5%, bulk density of 3.25 g cm⁻³, and lightweight index of 7.8% were successfully prepared, suitable for the working lining of metallurgical furnaces.     

铁尾矿制备轻质隔热保温建筑材料的研究

介绍了新型轻质隔热保温材料的制备工艺,以铁尾矿、废旧聚苯乙烯泡沫为主要原料,普通硅酸盐水泥为胶凝剂,制备轻质隔热保温材料.试验研究表明,当铁尾矿/(水泥 铁尾矿)取40%、泡沫/(水泥 铁尾矿)取4%、水/水泥取0.48时,所制备的试块7 d抗压强度可达0.94 MPa,28 d抗压强度可达1.05 MPa,而干燥容重仅740.6 kg/m3,导热系数仅0.109 W/(m·K),为综合利用尾矿和废弃泡沫提供了一条新的技术途径.     

生态建造：教育套餐和环境手册

生态建造是一个关注于传播建成环境中可持续性的需要以及促成可持续性的方式的项目。它针对于两个群体：16-19岁的学生，为他们制作了一个交互式的光盘；建造行业中的专业人员。光盘中提出了这样的问题--你的家和学校有多绿色？它说明了类似于建筑尺度和朝向的设计决策如何影响到建筑在能耗方面的表现和CO2的排放量。光盘包括了衡量如往宅温室节能效果的术语表，来解释它们对建筑的影响。这样学生们就可以对他们自己的学校和家进行评估，并提出怎样的设计可以提高它们的节能效果。如果我们想全球化地实现可持续性的未来，下一代的介入至关重要。环境手册中更深入地研究了这些问题，并关注到了其他建筑类型，如办公建筑。本文描述了正趋于完成的教育光盘和环境手册中涉及的一些根本的环境和教育因素。