摘要：The tensile properties of 2297-T87 Al–Li alloy thick plates at different thickness position and in different direction were analyzed via tensile testing,optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and transmission electron microscopy(TEM).Results indicated that the ultimate tensile strength(UTS)and yield strength(YS)of the alloy decreased firstly and then increased from the 1/8T position to the 1/2T position,whereas elongation to failure(Ef)decreased gradually such that its value along the rolling direction(RD)was higher than those along the transverse direction(TD)at the same thickness *** the 1/8T position to the 3/8T position of the alloy,the UTS and YS along the TD were higher than those along the *** the 1/2T position of the alloy,the UTS,YS,and Ef along the RD were the highest,whereas those along the normal direction(ND)were the *** observations further revealed that the anisotropy of tensile properties was related to grain morphology,crystal texture,second-phase particles,and Li atom segregation.

摘要：Developing microwave absorption(MA)materials with satisfied comprehensive performance is a great challenge for tackling severe electromagnetic *** particular,the magnetic component/carbon hybrids absorbers always suffer from high filler ***,we propose a feasible strategy to construct hierarchical porous carbon with tightly embedded Ni nanoparticles(Ni@NPC).These highly dispersed Ni nanoparticles produce strong magnetic coupling networks to enhance magnetic loss ***,the interconnected hierarchical dielectric carbon network affords favorable dipolar/interfacial polarization,conduction loss,multiple reflection and ***,with an ultralow filler loading of 5 wt.%,the resultant Ni@NPC/paraffin composite achieves an excellent MA performance with a minimum reflection loss of as high as-72.4 dB and a broad absorption bandwidth of 5.0 *** capability outperforms most current magnetic-dielectric hybrids ***,the MA capacity can be easily tuned with adjustments in thickness,content and type of magnetic ***,this work opens up new avenues for the development of high-performance and lightweight MA materials.

摘要：Based on the graphic theory and improved genetic algorithm,an improved genetic algorithm to search the minimum spanning trees is given . The algorithm uses binary code to represent the problem of minimum spanning trees. It designs the corresponding fitness function,operator and few controlling strategies to improve its speed and evolutionary *** one solution can be gotten with running traditional al-gorithem atone *** new algorithm can get a set of the solutions with higher probability in a shorter *** experiment shows that it has a better performance than traditional methods.

摘要：针对某胎面胶(TMG)挤出断面与施工设计断面局部误差较大问题,利用Polyflow软件,选取Phan-Thien and Tanner(PTT)本构模型和Navier滑移模型,逆向数值设计了该胶料的挤出口型。分析口型出口形状的成因,针对口型出口处速度场分布不均这一结果,选取不同流道长度逆向设计口型并分析其对挤出质量的影响。结果表明,胶料在口型出口处沿挤出方向的速度分布决定了逆向设计口型的出口构型;流道长度对口型出口截面积、胀大比、沿挤出方向的速度分布以及压力分布影响显著;逆向设计口型挤出断面与施工设计断面具有很好的一致性。

摘要：设计合成可作为碳纳米管片段的共轭芳烃大环近年来吸引了化学家们广泛的研究兴趣,人们希望从这些共轭芳烃大环出发,通过利用"自下而上"的策略合成单壁碳纳米管。需要指出的是,传统制备碳纳米管的方法,如电弧法、化学气相沉积法等,都很难形成均一的单壁碳纳米管。而这种"自下而上"的策略为高效合成尺寸均一的单壁碳纳米管提供了可行的方法,这种合成方法因此成为了当下合成单壁碳纳米管的热点,但也仍是一大挑战。本文从二维碳纳米环、碳纳米带和三维碳纳米笼三个方面概述关于这类共轭芳烃大环研究的新进展,着重介绍了共轭碳纳米环的设计原则和合成方法,并突出介绍了多环芳烃碳纳米环。多环芳烃通常具有优良的光电性质,以其为基元构筑的共轭碳纳米结构不仅可以作为碳纳米管的合成前体,而且其自身也会表现出新的光电性质。

摘要：隔膜是锂离子电池的重要组成部分,制备高性能的隔膜是提升电池性能的重要途径之一。文中通过化学交联方法制备了可用于锂离子电池的纤维素隔膜,即醋酸纤维素(CA)与交联剂六亚甲基二异氰酸酯(HDI)经缩合反应形成交联结构的纤维素基膜。结果表明,与商用聚乙烯隔膜相比,该膜拥有优异的热稳定性、力学强度和电化学性能,在200℃加热30 min几乎不发生热收缩,拉伸强度可达30.70 MPa,其组装的锂离子电池也拥有良好的循环充放电性能,在0.5 C/0.5 C的充放电条件下循环100圈后电池放电比容量可保持95%。

摘要：通过醋酸纤维素与甲基丙烯酰氯之间的酯化反应,成功合成了带双键的醋酸纤维素(M-CA)。以M-CA为基体材料,引入活性单体甲基丙烯酸甲酯(MMA),通过紫外光引发聚合制备了具有交联结构的锂离子电池隔膜。结果表明,该隔膜的耐溶剂性和电解液亲和性均得到明显提升;当MMA中双键量为M-CA中双键量的7倍时,所制备的CM7膜具有较好的综合性能,其吸液率为364%,机械强度为31.91 MPa,离子电导率为2.61 mS/cm;由CM7膜组装的LiFePO_(4)/Li锂离子电池具有良好的倍率放电能力和循环充放电稳定性。

摘要：为了缓解多台柱塞泵协同作业时注聚平台甲板振动响应过大的问题,本文基于阻尼剪切变形耗能原理提出了一种新型约束阻尼减振基座。利用Abaqus软件建立了柱塞泵-约束阻尼基座-注聚平台振动响应分析模型,探究了约束阻尼基座的阻尼材料损耗因子、阻尼层厚度和拓展层层数对其隔振特性的影响规律。研究表明,随着阻尼材料损耗因子、阻尼层厚度、拓展层层数的增加,约束阻尼基座的隔振性能将逐步增强,当阻尼材料损耗因子为1.0、阻尼层厚度为20 mm且拓展层数为3时,约束阻尼隔振基座的减振效果达到最优,其隔振量高达75.25 dB,可显著降低注聚平台的振动响应。

摘要：高速服务区车辆禁停检测面临场景复杂的挑战,目前基于单一车型信息的禁停检测算法受到昼夜光照变化、车辆重叠遮挡以及视角倾斜等因素的影响,无法在连续时间段内准确判断禁停区域内的车辆是否为同一辆车,存在较高的误检率和漏检率。为此,提出一种复杂环境下高速服务区禁停检测算法,首先使用YOLOv5车辆检测算法获取车型与位置信息,并给出一种改进禁停区域匹配方法,提升复杂环境下目标和区域匹配准确率;其次对禁停区域内目标车辆使用ConvNeXt车身颜色识别算法获取颜色信息;最后设计一种分阶段控制的多维信息匹配与融合策略,有效降低因光照、遮挡、视角等变化导致的车辆身份判断不准确情况,从而降低服务区车辆禁停检测的误报率与漏检率。实验结果表明,所提方法在高速服务区禁停数据集上的禁停误检率由3.56%下降到0.77%,禁停漏检率由11.3%下降到2.48%,不仅为服务区管理禁停行为提供了车辆多属性信息和车辆违停时长信息,而且满足服务区多场景部署的性能要求,可较好地用于实际应用中。

摘要：This paper investigates various Weber problems including unconstrained Weber problems and constrained Weber problems under l1, l2 and l∞-norms. First with a transformation technique various Weber problems are turned into a class of monotone linear variational inequalities. By exploiting the favorable structure of these variational inequalities, we present a new projection-type method for them. Compared with some other projection-type methods which can solve monotone linear variational inequality, this new projection-type method is simple in numerical implementations and more efficient for solving this class of problems; Compared with some popular methods for solving unconstrained Weber problem and constrained Weber problem, a singularity would not happen in this new method and it is more reliable by using this new method to solve various Weber problems.