摘要：Nowadays,the electromagnetic properties of artificial photonic materials can be well-tuned via designs over their composition and ***,engineering the properties of artificial materials at the nanoscale is challenging and *** we demonstrate a facile and low-cost method for fabricating large-area silver nanoparticle metasurfaces(AgNPMSs)by using the vectorial holography-mediated growth *** AgNPMS,which can be regarded as a hologram device,possesses excellent chiroptical *** vectorial holographic technique may open avenues for fabricating novel chiroptical metamaterials with large degrees of freedom,which can be further used for beam steering,photocatalysis,biosensing,etc.

摘要：Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperat-ures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly im-prove the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pre-treatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a cata-lyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.

摘要：纤维增强复合材料层合板的变刚度优化设计,通过逐点优化纤维铺角的可设计性,从而匹配结构中应力状态的空间变化,更高效地发挥纤维增强复合材料层合板在强度与刚度性能上的方向性,为设计师提供了更广阔的设计空间与设计灵活度.然而,基于梯度类算法的传统复合材料变刚度优化设计,因其设计变量众多,不可避免地在结构分析与灵敏度分析中面临大规模计算的挑战.同时,结构在概念设计阶段存在载荷工况随机性问题,如何在初始概念设计阶段,针对随机载荷工况制定高效的设计方案具有重要工程价值.近年来,随着人工智能与高性能计算的快速发展,基于传统优化获得的数据集构建端到端的机器学习模型,为实现实时的复合材料变刚度优化提供了可能.文章采用反向传播(back propagation,BP)神经网络算法,建立了基于机器学习的纤维增强复合材料变刚度优化设计方法.首先,基于正态分布纤维优化(normal distribution fiber optimization,NDFO)插值格式,构建以最小化结构柔顺度为目标的复合材料变刚度优化设计模型,考虑载荷大小与方向的随机性,获得神经网络模型训练所需的样本集数据.其次,以最小均方误差(means square error,MSE)为目标函数,采用BP神经网络模型对样本数据集进行训练.最后,建立基于皮尔逊相关系数(Pearson correlation coefficient)、均方误差的模型评价体系,对生成的神经网络模型进行评价.数值算例讨论了含圆孔MBB梁与悬臂C型梁变刚度优化设计,详细阐述了基于机器学习的复合材料变刚度优化方法的实施过程,系统地对比了所提出的基于机器学习的复合材料变刚度优化与传统基于NDFO插值格式复合材料变刚度优化设计结果在纤维铺角轨迹和目标函数的差异,验证了本方法的有效性.

摘要：针对仓储设备由于故障导致的振动异常、温度过高现象,设计振动及温湿度实时监测系统。下位机集成运动传感器、空气温湿度传感器、ARM微处理器、Flash存储器,采用RT-Thread操作系统,通过RS485或USB传送给上位机。实验表明:该系统可实时测量温湿度和三轴加速度,能够满足仓储设备早期常见故障的监测需求,有实际应用价值,扩展性好。

摘要：考虑凹槽与凹坑织构之间的协同润滑效应,在曲轴轴承表面设计了抛物线凹槽-球形凹坑复合织构,以改善轴承的润滑性能;为了分析抛物线凹槽-球形凹坑复合织构对曲轴轴承润滑性能的影响,基于平均Reynolds方程和Greenwood-Tripp微凸体接触方程构建了曲轴轴承的混合润滑模型,并采用质量守恒的边界条件处理油膜的破裂和再形成行为,分析了凹槽织构、凹坑织构与凹槽-凹坑复合织构的摩擦学性能,研究了凹槽-凹坑复合织构的分布位置和结构参数对轴承承载力和摩擦力的影响。分析结果表明:凹槽-凹坑复合织构具有高于凹槽织构的承载力和低于凹坑织构的摩擦力;存在最优的凹槽宽度为1.3mm,凹槽面积率为0.7,凹槽最大深度为25μm,凹坑数量为6,凹坑面积率为0.7,凹坑最大深度为20μm,使得轴承量纲为1的承载力最大;存在最优的凹槽宽度为2.6mm,凹槽面积率为0.7,凹槽最大深度为30μm,凹坑数量为15,凹坑面积率为0.7,凹坑最大深度为35μm,使得轴承量纲为1的摩擦力最小;当凹槽-凹坑复合织构的分布位置、结构参数取最优值时,相对于无织构轴承而言,轴承的承载力提高了4.1%,摩擦力减小了19.6%。

摘要：碳纳米管作为新一代热界面材料,在天然材料中具有最高的热导率,有望解决金刚石半导体超高热流密度的散热问题.因此,本文提出将金刚石和碳纳米管结合,可大幅度提高器件性能及稳定性,减小封装尺寸,实现器件小型化设计.采用非平衡分子动力学方法从微观层面探究了金刚石/碳纳米管异质结构界面热特性及影响因素.研究发现碳纳米管层数增加使声子态密度峰值增大并向低频波段移动,低频声子增多更有利于界面传热,同时声子重叠能提高,声子耦合振动增强提升了界面传热效率;同时,一定范围内体系温度的升高及碳纳米管长径比的增大可以提高近界面处金刚石和碳纳米管的态密度截止频率,提升低频波段的峰值,进一步增强两侧声子的耦合振动,提高了界面热导.最后,采用正交试验模拟获得了金刚石/碳纳米管界面热导的最优值,结果远优于目前一般半导体/金属的界面热导.该工作为优化金刚石/碳纳米管异质界面的热输运提供了思路,并将有利于器件热管理和芯片材料设计.

摘要：本文研究了外部量子点耦合作用下,量子点耦合两个手性Majorana费米子体系的共振交换.为了观察两个手性Majorana费米子的共振交换,提出了一种基于量子反常霍尔绝缘体(QAHI)近邻耦合s波超导体的电路.数值计算的结果表明,通过外部量子点耦合强度可以调节手性Majorana费米子的共振透射.如果经历了共振隧穿的一个手性Majorana费米子与另一个量子点或Majorana零能模发生共振耦合,则可以实现与超导相位无关的非阿贝尔编织操作.因此所设计方案为Majorana费米子的非阿贝尔编织操作提供一种新的方式,这些发现可能在拓扑量子计算的实现中具有潜在的应用价值.

摘要：船冰碰撞是一个复杂的动力学过程,如何得到碰撞中的冰载荷一直是船舶碰撞研究领域的热点之一。本文分别建立300 000 t冰区航行船和层冰的有限元模型,基于弹塑性理论及非线性有限元理论,利用***对其碰撞进行数值仿真,模拟了船首及层冰的接触碰撞过程,最终得到船冰碰撞过程中的碰撞力、船首结构响应、船航速变化及能量耗散等参数。分析船冰碰撞过程中的碰撞机理及特性,并对冰区航行船特别是其船壳提出结构加强的建议,为设计冰区航行船提供一定的参考。

摘要：以叶轮给煤机的水平驱动力与拨煤量比值的最小值作为优化目标,建立叶轮给煤机的优化模型,选取相关参数作为设计变量,并采用改进的粒子群优化算法,在MATLAB软件中编写程序对叶轮给煤机的相关参数进行优化,通过对模型的优化,在提高拨煤量的同时,有效地减小了给煤机的水平驱动力,达到了优化的目的。

摘要：The input/output(I/O)pins of an industry-level fluorescent optical fiber temperature sensor readout circuit need on-chip integrated high-performance electro-static discharge(ESD)protection *** is difficult for the failure level of basic N-type buried layer gate-controlled silicon controlled rectifier(NBL-GCSCR)manufactured by the 0.18µm standard bipolar-CMOS-DMOS(BCD)process to meet this ***,we propose an on-chip integrated novel deep N-well gate-controlled SCR(DNW-GCSCR)with a high failure level to effectively solve the problems based on the same semiconductor *** computer-aided design(TCAD)simulation is used to analyze the device *** are tested by transmission line pulses(TLP)to obtain accurate ESD *** holding voltage(24.03 V)of NBL-GCSCR with the longitudinal bipolar junction transistor(BJT)path is significantly higher than the holding voltage(5.15 V)of DNW-GCSCR with the lateral SCR path of the same ***,the failure current of the NBL-GCSCR device is 1.71 A,and the failure current of the DNW-GCSCR device is 20.99 *** the gate size of DNW-GCSCR is increased from 2µm to 6µm,the holding voltage is increased from 3.50 V to 8.38 *** optimized DNW-GCSCR(6µm)can be stably applied on target readout circuits for on-chip electrostatic discharge protection.