摘要：通讯技术不断升级以及移动设备的快速发展极大改善了人们生活,但也带来了电磁干扰和信息安全问题.因此,亟需开发高性能电磁屏蔽材料来抑制电磁辐射和阻止信息泄露.研究发现,在外力作用下填料的自取向行为有助于实现聚合物基复合材料电磁屏蔽性能的提升,因此如何在聚合物基体中构筑有效的填料取向结构正成为电磁屏蔽材料研究的热点.本文首先关注外场诱导复合材料内导电网络的构建策略.随后,梳理了利用外场诱导无机填料取向制备聚合物基电磁屏蔽复合材料的研究进展,其中外场包括温度场、静电场、重力场、机械力场和磁场.值得注意的是,基于外场诱导制备的独特结构与电磁波之间的特殊响应关系通过精选的案例被进一步剖析.最后,提出外场辅助制备聚合物基电磁屏蔽复合材料各自亟待解决的关键科学和技术问题,并对未来的发展方向进行了理性预测.本文讨论的方法和提出的策略有望为高性能聚合物基电磁屏蔽复合材料的创新设计提供一些指导意见.

摘要：Several catalysts comprising Pt supported on octahedral Fe3O4（Pt/Fe3O4） were prepared by a facile method involving co-precipitation followed by thermal treatment at different temperatures. A variety of characterization results revealed that this preparation process afforded highly crystalline octahedral Fe3O4 with a uniform distribution of Pt nanoparticles on its surface. The thermal-treatment temperature significantly influenced the redox properties of the Pt/Fe3O4 catalysts. All the Pt/Fe3O4 catalysts were found to be catalytically active and stable for the oxidation of low-concentration formaldehyde（HCHO） with oxygen. The catalyst prepared by thermal treatment at 80 °C（labelled Pt/Fe3O4-80） exhibited the highest catalytic activity, efficiently converting HCHO to CO2 and H2 O under ambient temperature and moisture conditions. The excellent performance of Pt/Fe3O4-80 was mainly attributed to beneficial interactions between the Pt and Fe species that result in the formation a higher density of active interface sites（e.g., Pt-O-FeO x and Pt-OH-FeO x）. The introduction of water vapor improves the catalytic activity of the Pt/Fe3O4 catalysts as it participates in a water-assisted dissociation process.

摘要：The squirrel-cage elastic support is one of the most important components of an aero-engine rotor system.A proper structural design will favor the static and dynamic performances of the *** view of the deficiency of the current shape optimization techniques,a new mapping approach is proposed to define shape design variables based on the parametric equations of 3D curves and *** is then applied for the slot shape optimization of a squirrel-cage elastic *** this end,an automatic design procedure that integrates the Genetic Algorithm (GA) is developed to solve the *** typical examples with different shape constraints are *** results provide reasonable optimum designs for the improvement of stiffness and strength of the squirrel-cage elastic support.

摘要：Turbine cascade optimum design, the typical non-convex optimal problem, has long been a design challenge in the engineering fields. The new type hybrid Genetic Algorithms-whole annealing GeneticAlgorithms have been developed in this paper. Simulated annealing selection and non-uniform mutation are adopted in the whole annealing Genetic Algorithms. Whole annealing Genetic Algorithmsoptimal performance have been tested through mathematical test functions. On this basis, turbinecascade inverse design using whole annealing Genetic Algorithms have been presented. The B-Splinefunction is applied to represent the cascade shape. C-type grid and Godunov scheme are adopted toanalysis the cascade aerodynamic performance. The optimal problem aims to obtain an cascade shapefrom different initial cascade through the given target pressure distribution. The optimum cascadeshape is in well agreement with the target cascade shape. The numerical results show that the wholeannealing Genetic Algorithms are the powerful optimum tools for turbine optimum design or othercomplex engineering design problems.

摘要：To Make Better VillagesAuthor:He Xuefeng Year:2017 Publisher:Peking university Press ISBN:9787301281185(328 pages,in Chinese)In the context of the rural revitalization strategy,how to effectively bring design to the countryside is a key concern of urban and rural planning *** book To Make Better Villages is a weighty contribution to our understanding of rural issues,and is inspiring for effectively bringing design to the countryside.

摘要：The upcoming fifth-generation(5G)mobile communication with low-latency,high-speed and high-data-capacity[1]can realize innovative services such as remote intelligent medical care,smart cities,Internet of Vehicles,and ultra-high-definition video[2,3].Compared with current mobile communications,5G services require a 5G network with 1000 times the capacity and 10–100 times the data transmission rate[4].5G communication can also realize large-scale connections between people and machines[5].It will be the era of Internet of *** realization of the interconnection of all things is essentially the communication between the transmitting antenna and the receiving antenna.

摘要：认识剪切型岩爆的触发机理对地下工程科学设计与安全施工具有重要意义。为揭示隧道围岩(DTR)的剪切触发型岩爆机理,进行了砂岩的双矩形隧道和双圆形隧道物理模型剪切试验。在剪切试验过程中,利用高速摄像机和声发射监测仪对DTR的岩爆过程进行监测和记录,揭示了压剪下DTR的宏观和细观断裂特征;进而建立了5种隧道间距数值模型,分析了压剪下含隧洞试样连续-非连续剪切过程及其触发的岩爆机理;提出了一种新的能量冲击指数(S)来评价剪切型岩爆倾向性。试验结果表明,在剪切试验中,DTR的实时剪切特征、内外破裂特征和微裂纹数演化特征可划分为4个典型阶段:整体剪切压缩阶段(Ⅰ阶段)、以裂纹萌生为主的弹性阶段(Ⅱ阶段)、以裂纹扩展-贯通和剪切岩爆为主的剪切破裂阶段(Ⅲ阶段)和剪切摩擦阶段(Ⅳ阶段)。此外,试验结果还表明DTR在剪切型岩爆发生后可形成对称猫耳形缺口;微裂纹演化过程中DTR经历了裂纹预备阶段(Ⅰ阶段)、裂纹初始增长阶段(Ⅱ阶段)、裂纹快速增长阶段(Ⅲ阶段)和裂纹稳定阶段(Ⅳ阶段)。更重要的是,综合分析发现,双矩形隧道和双圆形隧道触发剪切型岩爆机制存在差别的本质是截面形状导致的结构效应,即双矩形隧道和双圆形隧道应力场分布差异导致断裂行为不同。研究结果有利于加深对剪切型岩爆机理的认识,为岩土工程防治提供理论依据。

摘要：本文介绍了一种基于横向可移动栅极场效应晶体管(LMGFET)的新型微型力传感器的开发。提出了一种精确的电气模型,用于小型LMGFET器件的性能评估,与以前的模型相比,其精度有所提高。采用了一种新型三明治结构,该结构由一个金交叉解耦栅阵列层和两个软光阻层SU-8组成。通过所提出的双差分传感结构,LMGFET横向工作在垂直干扰下的输出电流被大大消除,所提出传感器的相对输出误差从4.53%(传统差分结构)降低到0.01%。提出了一种实用的传感器制造工艺,并对其进行了模拟。基于LMGFET的力传感器的灵敏度为4.65μA·nN^(-1),可与垂直可移动栅极场效应晶体管(VMGFET)器件相媲美,但非线性度提高了0.78%,测量范围扩大了±5.10μN。这些分析为LMGFET器件的电气和结构参数提供了全面的设计优化,并证明了所提出的传感器在生物医学显微操作应用中具有良好的力传感潜力。

摘要：The design and synthesis of high‐performance and low‐cost electrocatalysts for the hydrogen evolution reaction(HER),a key half‐reaction in water electrolysis,are *** to their modest hydrogen adsorption energy,ruthenium(Ru)‐based nanomaterials are considered outstanding candidates to replace the expensive platinum(Pt)‐based HER *** this study,we developed an adsorption‐pyrolysis method to construct nitrogen(N)‐doped graphene aerogel(N‐GA)‐supported ultrafine Ru nanocrystal(Ru‐NC)nanocomposites(Ru‐NCs/N‐GA).The particle size of the Ru‐NCs and the conductivity of the N‐GA substrate can be controlled by varying the pyrolysis *** experiments reveal revealed that 10 wt%Ru‐NCs/N‐GA nanocomposites require overpotentials of only 52 and 36 mV to achieve a current density of 10 mA cm^(−2) in 1 mol/L HClO4 and 1 mol/L KOH electrolytes for HER,respectively,which is comparable to 20 wt%Pt/C *** from the ultrafine size and uniform dispersion of the Ru‐NCs,the synergy between Ru and the highly conductive substrate,and the anchoring effect of the N atom,the Ru‐NCs/N‐GA nanocomposites exhibit excellent activity and durability in the pH‐universal HER,thereby opening a new avenue for the production of commercial HER electrocatalysts.

摘要：Synergistic optimization of donor-acceptor blend morphologyis a hurdle in the path of realizing efficient non-fullerene small-molecule organic solar cells(NFSMOSCs)due to the anisotropic conjugated backbones of both donor and ***,developing a facile molecular design strategy to effectively regulate the crystalline properties of photoactive materials,and thus,enable the optimization of blend morphology is of vital *** this study,a new donor molecule B1,comprising phenyl-substituted benzodithiophene(BDT)central unit,exhibits strong interaction with the non-fullerene acceptor BO-4 Cl in comparison with its corresponding thiophene-substituted BDT-based material,*** a result,the B1 is affected and induced from an edgeon to a face-on orientation by the acceptor,while the BTR and the acceptor behave individually for the similar molecular orientation in pristine and blend films according to grazing incidence wide angle X-ray scattering *** means the donor-acceptor blend morphology is synergistically optimized in the B1 system,and the B1:BO-4 Cl-based devices achieve an outstanding power conversion efficiency(PCE)of 15.3%,further certified to be 15.1%by the National Institute of Metrology,*** results demonstrate a simple and effective strategy to improve the crystalline properties of the donor molecule as well as synergistically optimize the morphology of the all-small-molecule system,leading to the high-performance NFSM-OSCs.