一种两层复合式微驱动平台的运动分析

介绍了一种复合式的微驱动平台机构,采用几何理论方法对它进行了运动分析,建立了运动学方程。通过实例证明了其可行性。     

Facile synthesis of hybrid porous composites and its porous carbon for enhanced H2 and CH4 storage

The anticipated energy crisis due to the extensive use of limited stock fossil fuels forces the scientific society for find prompt solution for commercialization of hydrogen as a clean source of energy. Hence, convenient and efficient solid-state hydrogen storage adsorbents are required. Additionally, the safe commercialization of huge reservoir natural gas (CH₄) as an on-board vehicle fuel and alternative to gasoline due to its environmentally friendly combustion is also a vital issue. To this end, in this study we report facile synthesis of polymer-based composites for H₂ and CH₄ uptake. The cross-linked polymer and its porous composites with activated carbon were developed through in-situ synthesis method. The mass loadings of activated carbon were varied from 7 to 20 wt%. The developed hybrid porous composites achieved high specific surface area (SSA) of 1420 m²/g and total pore volume (TPV) of 0.932 cm³/g as compared to 695 m²/g and 0.857 cm³/g for pristine porous polymer. Additionally, the porous composite was activated converted to a highly porous carbon material achieving SSA and TPV of 2679 m²/g and 1.335 cm³/g, respectively. The H₂ adsorption for all developed porous materials was studied at 77 and 298 K and 20 bar achieving excess uptake of 4.4 wt% and 0.17 wt% respectively, which is comparable to the highest reported value for porous carbon. Furthermore, the developed porous materials achieved CH₄ uptake of 8.15 mmol/g at 298 K and 20 bar which is also among the top reported values for porous carbon.     

Hybrid electric power plant sizing strategy based on ab-initio fuel cell design for weight minimization

This work presents a methodology for the design of a hydrogen fuel cell-based hybrid electric power plant for hybrid electric vehicles (HEV), where a battery bank and ultracapacitors are also considered as components of the hybrid power plant. The methodology considers the design features of an electric vehicle and evaluates its energy and power requirements as to fulfil a driving cycle. The work starts by weight minimizing a fuel cell taking into consideration its physical and electrochemical characteristics. Batteries and ultracapacitors are then sized according to their dynamic response features and considering specifications from commercial candidate cells, to propose an electric configuration and specify the baseline for a hybrid power plant. In order to illustrate the methodology, a crossover utility electric vehicle and a WLTC class I drive cycle are used. This work shows that by reducing the power plant size, power and energy requirements can also be minimized and the overall performance can be increased promoting fuel and costs savings. For comparison and to show the impact of weight minimization on the energy on board and cost, this work presents the energy and power required by different power plant configurations. Results showed that including ultracapacitors to the power plant offers more benefits, such as less stress on batteries, at a marginal initial cost compared to a case without ultracapacitors, where batteries should attend transients with a limited capability for energy recovery from regenerative breaking. The methodology is easily implemented and does not large computational resources providing with a power plant baseline for further design stages, such as particular energy management approaches depending on particular priorities for the developer, such as range, productivity and performance, economy and others.     

基于分布式计算的月度机组组合高效算法设计

月度机组组合是电力系统运行方式安排的重要内容。随着电网规模的不断扩大,月度机组组合计算规模快速增加。传统的月度机组组合计算方法在计算效率上已不能满足当前系统要求。为此,介绍了分布式计算基本概念,提出了一种基于混合维度粒子群算法的分布式计算方法。根据月度机组组合模型实际,设计了面向月度机组组合问题的分布式高效计算方法,通过将传统串行计算转换为并行计算,提升了整体计算效率。最后基于某电网实际构造算例,验证了本文所提出方法的有效性。     

Hybrid laser/arc welding of thick high-strength steel in different configurations

In this investigation, hybrid laser/arc welding (HLAW) was employed to join 8-mm-thick high-strength quenched and tempered steel (HSQTS) plates in the butt-and T-joint configurations. The influences of welding parameters, such as laser power, welding speed, stand-off distance (SD) between the arc of gas metal arc welding, and the laser heat source on the weld quality and mechanical properties of joints, were studied to obtain non-porous and crack-free fully-penetrated welds. The weld microstructure, crosssection, and mechanical properties were evaluated by an optical microscope, and microhardness and tensile tests. In addition, a finite element model was developed to investigate the thermal history and molten pool geometry of the HLAW process to join the HSQTS. The numerical study demonstrated that the SD had a paramount role in good synergy between the heat sources and the stability of the keyhole. For the butt-joint configuration, the results showed that, at a higher welding speed (35 mm/s) and optimum SD between the arc and laser, a fully-penetrated sound weld could be achieved. A non-porous weld in the T-joint configuration was obtained at a lower welding speed (10 mm/s). Microstructural evaluations indicated that the formation of residual austenite and the continuous network of martensitic structure along the grain boundary through the heat affected zone were the primary reasons of the softening behavior of this area. This was confirmed by the sharp hardness reduction and failure behavior of the tensile coupons in this area.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-017-0193-6     

基于光控压电混合驱动悬臂梁独立模态控制

本文提出利用镧改性锆钛酸铅（PLZT）的光电效应,将PLZT作为电动势源来驱动压电作动器,从而实现光控板壳结构的振动控制。基于光控压电等效电学模型建立了光控压电混合驱动的数学模型,并进行了实验验证。为了实现光控悬臂梁的独立模态控制,针对悬臂梁结构,设计了正交模态传感器/作动器表面电极形状函数。提出PLZT与压电作动器正/反接控制的激励策略,并结合速度反馈定光强控制的控制算法,利用Newmark-β法对不同光照强度下悬臂梁的动态响应进行了数值仿真分析。分析结果证明了本文所设计的模态传感器/作动器及针对光控压电混合驱动提出的控制策略的正确性。     

Preparation of a Novel Coal Gangue-Polyacrylamide Hybrid Flocculant and Its Flocculation Performance

A novel flocculant based on hybrid coal gangue-polyacrylamide (HCGPAM) has been prepared by using modified coal gangue and polyacrylamide. Factors related to the preparation such as reaction time, temp...     

基于准静态电磁场的变压器线圈中特快速暂态仿真建模

基于准静态电磁场原理提出了一种在快速暂态过电压的作用下以单匝中并联导线为单元支路和以两段线匝为单元支路相结合的集中参数混合线圈模型。通过单匝单线模型可准确计算陡波冲击下的匝间过电压,结合两段线匝模型可有效减少仿真时间。拓扑网路的大小和参数与变压器的结构和特性有关,网络中的电感和电容等参数是无源和线性的,但它们与传播电磁波的介质有内在的联系。给出了模型参数的计算方法,并对以两段线饼为单元支路的线圈模型进行了截波冲击下的仿真分析,变压器首端对地电压的仿真结果与实测结果比较接近,证明了该模型的正确性。     

现代盘式车轮电机设计技术

提出一种用于混合动力汽车的高密度盘式车轮电机,文中讨论了该电机的结构、性能和特点,并提出混合动力汽车牵引电机的现代设计理念和原则.     

燃料电池中巴车电电混合动力控制系统

针对燃料电池电压电流输出特性及动态响应滞后的特点,提出燃料电池加辅助电源的中巴车电电混合动力系统方案。采用燃料电池加镍氢电池加超级电容的三能源结构作为整车的驱动电源,设计了整个动力系统的基本结构。通过分析动力系统的驱动模式,引入智能协调和预测控制思想,设计了燃料电池中巴车混合动力协调控制系统。采用三层前馈神经网络建立系统的非线性预测模型,对燃料电池发动机功率预测控制系统进行了研究和优化,给出了具体的预测控制算法步骤。仿真实验结果表明该控制策略具有良好的控制效果,减少了燃料电池发动机输出功率的频繁波动,整车动力性及经济性都得到了加强。