求解离散优化问题的元胞量子狼群演化算法

针对离散空间优化问题,提出了求解离散优化问题的元胞量子狼群演化算法,首先,为了提高算法的全局收敛速度,采用双策略量子位初始化方法和滑模交叉方法,分别生成量子狼群初始位置和产生头狼,实现种群多样性;其次,为了描述头狼与猎物间的距离以及增强狼群的遍历范围,采用二进制编码方式和元胞自动机中的演化规则,分别实现狼群中个体狼与猎物距离的精确描述和量子旋转角的选取调整;然后,为了证明该算法的收敛性能,采用泛函分析方法,实现了算法全局收敛性能的验证;最后,通过6个标准测试函数的仿真实验,并与狼群算法以及量子狼群算法的优化结果进行比较。实验结果表明,该算法具有较快的收敛速度和较好的全局寻优能力。     

车载动力电池组温升特性仿真及实验研究

利用ANSYS有限元软件对车载LiFePO4锂离子电池组进行温升特性仿真分析,同时,通过高低温实验箱和放电电流控制器模拟电池组的工作环境,对锂离子电池组进行了放电实验,对电池组温升特性进行了分析,以验证ANSYS模拟仿真的正确性与真实性,据此获得锂离子电池热稳定性及安全性随放电电流、温度变化的规律,以及在电池组串联过程中随体积/表面积之比变化的规律,以得到其更真实的热特性。     

一种多电池包并联技术的研究

在电池应用系统中为了提高电池的容量以及可靠性采用多个电池包进行并联,从理论上来讲两个源是不能并联的。实际应用中为了实现各个电池包之间的相互独立采用了二极管与电池包串联来实现隔离,但是此隔离二极管会造成一定程度地功率损失。为了降低多电池包并联采用二极管隔离所带来的功率损失,结合同步整流技术在开关电源中的应用,并结合其控制原理采用MOS管来代替二极管并通过相应的控制电路来控制MOS管的导通与关断,从而达到与二极管隔离同样的效果。与此同时,由于MOS管具有极低的导通电阻从而降低了隔离这个部分的损耗。仿真与实验结果均证明了此设计方案的正确性与可行性。     

The bipolar plate of AISI 1045 steel with chromized coatings prepared by low-temperature pack cementation for proton exchange membrane fuel cell

The low-temperature pack chromization, a reforming pack cementation process, is employed to modify AISI 1045 steel for the application of bipolar plates in PEMFC. The process is conducted to yield a coating, containing major Cr-carbides and minor Cr-nitrides, on the substrate in view of enhancing the steel's corrosion resistance and lowering interfacial contact resistance between the bipolar plate and gas diffusion layer. Electrical discharge machining and rolling approach are used as the pretreatment to produce an activated surface on the steel before pack chromization process to reduce operating temperatures and increase deposition rates. The rolled-chromized steel shows the lowest corrosion current density, 3 × 10⁻⁸ A cm⁻², and the smallest interfacial contact resistance, 5.9 mΩ cm², at 140 N cm⁻² among all tested steels. This study clearly states the performance of 1045 carbon steel modified by activated and low-temperature pack chromization processes, which possess the potential to be bipolar plates in the application of PEMFC.     

浅析层状复合板轧制新工艺

本文在对国内外层状金属复合板生产研究文献查阅分析的基础上,着重介绍了钎焊热轧法、燃烧合成轧制法、包套轧制法、PPR方法、ARB方法、PIT方法等复合新工艺基本工作原理,以及目前国内外应用各种新工艺所生产研究的新材料复合板,同时分析了复合板生产存在的问题,展望了复合板生产工艺的发展方向。     

相变胶囊堆积形态对蓄热系统性能的影响分析

建立相变蓄热胶囊的三维有序及无序堆积模型,在此基础上分析相变蓄热胶囊有序及无序对蓄热系统特性的影响.通过对蓄热系统的蓄热量、蓄热用时、蓄热效率及系统内温度分布等关键性能指标情况分析,提出一种判定蓄热终点的新方法.结果表明:当采用有序堆积时系统的各项性能指标最优,叉排堆积时蓄热效率最低,而无序堆积时蓄热总量最少.另外,换...     

Exploring the heat transfer performance of nanofluid as a coolant for power battery pack

Nanofluids with high thermal conductivity coefficient are introduced to the thermal management system of power battery packs for electric vehicles and hybrid electric vehicles. Two typical cooling structures of cylindrical and square battery packs are described, and their flow models are established. By similarity transformations, the nonlinear system of partial differential equations is reduced and then solved numerically by the shooting method. The heat transfer properties of three types of nanofluids, that is, CuO‐EG, Al₂O₃‐EG, TiO₂‐EG, are analyzed in detail. It is found that CuO‐EG nanofluid is the best coolant for the cylindrical battery pack, whereas Al₂O₃‐EG nanofluid is the best choice for square battery pack cooling.     

Gas exchange in modified atmosphere packaging. 1: A new theoretical approach for micro-perforated packs

Gas transport and exchange through the perforations in micro-perforated packs used in modified atmosphere packaging were numerically modelled by using Stephan-Maxwell laws, and, outside these perforations, by Fick's law. the model accounts simultaneously for oxygen, carbon dioxide, nitrogen, argon and water vapour. Fruit and vegetable respiration was approximated by Michaelis-Menten kinetics depending on oxygen concentration with an uncompetitive inhibition due to carbon dioxide. Concentration equilibrium was reached after 2 to 3 days, depending on the void volume and on the diffusion properties of the packs. the equilibrium concentrations were dependent on the number of perforations, their diameter, the thickness of the film and the temperature. However, a pack which makes 10% oxygen possible within the pack at 10°C might induce anaerobiosis at 20°C.     

High-temperature coating for titanium aluminides using the pack-cementation technique

The practical application of titanium aluminide metal-matrix composites (MMCs) at high temperatures requires suitable surface coatings to provide the needed oxidation resistance. Without a coating, the titanium aluminide alloys suffered from rapid oxidation attack at elevated temperatures, particularly under thermal cyclic conditions. The pack-cementation coating process was utilized to aluminize the surface region of a Ti₃Al-base alloy to TiAl₃, the most oxidation-resistant phase. With the existence of an adherent conversion coating, a thin protective alumina scale formed on the outer surface, and a significant improvement in the corrosion resistance was observed. Excellent coating efficiency and geometric flexibility were demonstrated in this study by the pack-cementation technique. Further development of the cementation process will focus on the elimination of surface cracking in the coating.     

气相缓蚀干燥材料的研究进展

叙述了钼酸铵-硅胶-聚乙烯气相缓蚀干燥材料研究的进展，用这种材料包装黑色与有色金属制件可有效地防止制件的点蚀、麻蚀和失泽。