摘要：A two-dimensional panel in subsonic flow with stochastic excitation is studied by assuming that the aerodynamic pressure contains random pressure *** on the global properties,the sensitivities of system parameters and noise intensities are ***,the parameter region with multiple coexisting attractors under different dynamic pressures is *** is found that the coexistence of multiple attractors extensively appears and the basin structure may be *** the periodic time history diagrams are calculated by simulating the random pressure fluctuation as Poisson white *** results show that under typical bistable conditions,the noise sensitivity of the subsonic panel system is related to the basin structures and the disposition of the coexisting attractors to the *** transition between two attractors diffuses along the unstable manifold and tends to the position where the basin boundary curvature is relatively *** findings underscore the importance of global analysis in assessing the noise load carrying capacity,which provides some valuable insights into the safety design of subsonic panel systems.

摘要：High spatiotemporal resolution brain electrical signals are critical for basic neuroscience research and high-precision focus diagnostic localization,as the spatial scale of some pathologic signals is at the submillimeter or micrometer *** entails connecting hundreds or thousands of electrode wires on a limited *** study reported a class of flexible,ultrathin,highdensity electrocorticogram(ECoG)electrode *** challenge of a large number of wiring arrangements was overcome by a laminated structure design and processing technology *** flexible,ultrathin,high-density ECoG electrode array was conformably attached to the cortex for reliable,high spatial resolution electrophysiologic *** minimum spacing between electrodes was 15μm,comparable to the diameter of a single *** hundred electrodes were prepared with an electrode density of 4444 mm^(-2).In focal epilepsy surgery,the flexible,high-density,laminated ECoG electrode array with 36 electrodes was applied to collect epileptic spike waves inrabbits,improving the positioning accuracy of epilepsy lesions from the centimeter to the submillimeter *** flexible,high-density,laminated ECoG electrode array has potential clinical applications in intractable epilepsy and other neurologic diseases requiring high-precision electroencephalogram acquisition.

摘要：With the increasing attention received by lightweight metals,numerous essential fields have increased requirements for mag-nesium(Mg)alloys with good room-temperature and high-temperature mechanical ***,the high-temperature mechanic-al properties of commonly used commercial Mg alloys,such as AZ91D,deteriorate considerably with increasing *** the past several decades,extensive efforts have been devoted to developing heat-resistant Mg *** approaches either inhibit the gen-eration of thermally unstable phases or promote the formation of thermally stable precipitates/phases in matrices through solid solution or precipitation *** this review,numerous studies are systematically introduced and *** alloy systems,includ-ing those based on Mg–Al,Mg–Zn,and Mg–rare earth,are carefully classified and compared to reveal their mechanical properties and strengthening *** emphasis,limitations,and future prospects of these heat-resistant Mg alloys are also pointed out and dis-cussed to develop heat-resistant Mg alloys and broaden their potential application areas in the future.

摘要：A combination of hydrogels and microfluidics allows the construction of biomimetic three-dimensional(3D)tissue models in vitro,which are also known as *** hydrogel patterningwith awell-controlled spatial distribution is typically achieved by embedding sophisticated microstructures to act as a ***,these physical barriers inevitably expose cells/tissues to a less physiologically relevant microenvironment than in vivo ***,we present a novel dissolvable temporary barrier(DTB)strategy that allows robust and flexible hydrogel patterning with great freedom of design and desirable flow stimuli for cellular *** key aspect of this approach is the patterning of a water-soluble rigid barrier as a guiding path for the hydrogel using stencil printing technology,followed by a barrier-free medium perfusion after the dissolution of the *** and multiple tissue compartments with different geometries can be established using either straight or curved DTB *** effectiveness of this strategy is further validated by generating a 3D vascular network through vasculogenesis and angiogenesis using a vascularized microtumor *** a new proof-of-concept in vasculature-on-a-chip,DTB enables seamless contact between the hydrogel and the culture medium in closed microdevices,which is an improved protocol for the fabrication ofmultiorgan ***,we expect it to serve as a promising paradigm for organ-on-a-chip devices for the development of tumor vascularization and drug evaluation in the future preclinical studies.

摘要：以粗集料的力学指标、分形维数以及BPN作为研究对象进行数据采集,基于前馈神经网络算法与支持向量机算法,提出了一种新型路面抗滑性能预测模型.采用加速加载试验,记录沥青混合料在轮载作用下表面抗滑性能的衰减过程,并利用指数模型对轮载次数与BPN的数值关系进行拟合.通过灰色关联度分析和相关性分析,评估各项因素对沥青路面抗滑性的影响程度.基于主成分分析结果,设计了6种方案,用于前馈神经网络算法和支持向量机算法的训练、验证和测试.结果表明,不同类型集料呈现出不同的抗滑性能,石英砂岩最佳,玄武岩次之,石灰岩较差.磨光值与沥青抗滑性能衰减模型的关联性最高.前馈神经网络算法构建的模型表现更为稳定,R 2值约为0.8,展现出良好的预测能力.

摘要：受到水合镁离子的高脱溶能垒和不良界面水分解行为的限制,水系镁离子电池通常受制于缓慢的离子传输动力学和严重的阴极溶解.为了克服这些障碍,受细胞膜两亲性结构的启发,我们成功构建了一种由疏水性聚(3,4-乙二氧基噻吩)(PEDOT)和亲水性α-MnO_(2)基底组成的MnO_(2)碳基阴极.结合实验和理论计算结果分析,PEDOT层可以有效提高整体电极的导电性,降低水合Mg^(2+)的脱溶能垒,并抑制阴极溶解,从而提高复合电极的性能.因此,本文所制备的复合电极表现出优越的速率性能(58.4mA hg^(-1),3Ag^(-1))和增强的长期循环稳定性(1000个循环后85.92mA hg^(-1),2Ag^(-1)),优于原始的α-MnO_(2)阴极.这项基于生物启发设计理念的工作将为水合镁离子电池的发展提供创新方向.

摘要：石墨烯因其高载流子迁移率和宽光谱吸收范围而广泛应用于光电探测。然而,其低光吸收率导致的高暗电流严重限制了它的光电探测性能。钼基二硫族化合物(MoX_(2),X=S、Se和Te)具有高的吸收系数,能够弥补石墨烯基光电探测器中暗电流较高的劣势,因此基于石墨烯/MoX_(2)范德华异质结的光电探测器能够表现出优异的光电子特性。本综述首先回顾了光电探测器的工作原理、性能指标和结构。之后,从材料基础的角度突出了石墨烯/MoX_(2)范德华异质结光电探测器的重要性。接着,总结了石墨烯/MoX_(2)范德华异质结光电探测器的制备方法和性能增强策略。最后,强调了这类异质结光电探测器当前面临的挑战及未来的发展方向。本综述将为这类高性能范德华异质结光电探测器的设计提供一定的指导和参考。

摘要：准二维钙钛矿表现出独特的光物理性质,这使它们成为激光技术潜在进步的优秀候选材料.高性能纳秒脉冲激光和放大自发发射(ASE)是实现连续波抽运光电泵浦激光器的关键工艺.然而,在纳秒脉冲激光泵浦下发展准二维钙钛矿ASE或激光仍然存在一些困难,包括表面缺陷浓度高、俄歇复合和能量传递效率低.本文通过无添加剂的Cs^(+)阳离子掺杂策略,可以很好地控制准二维钙钛矿膜的形貌和相分布,从而解决了低n相导致的能量传递途径不足的问题.本文通过快速的能量传递过程揭示了增益性质和载流子复合.基于此,掺杂适当比例Cs^(+)阳离子的PEA_(2)(FA_(0.7)Cs_(0.3))_(2)Pb_(3)Br_(10)钙钛矿膜的净增益系数比原始钙钛矿薄膜提高了近3倍,从而将纳秒激光激发下的放大自发发射阈值降低到1/3.研究结果表明,在准二维钙钛矿中掺杂Cs^(+)可为实现高性能激光器件的相位分布设计提供见解.

摘要：跟踪注册是增强现实(Augmented reality,AR)中一项至关重要的技术。基于人工标识和基于图像的注册方法已广泛应用于增强装配系统中。然而,由于空间产品的弱纹理、结构对称、数据有限以及难以张贴标识等特点,空间站的跟踪注册仍面临挑战。本文提出了一种专门为中国空间站诱导维修应用设计的三维物体跟踪方法,旨在用AR技术取代传统的纸质手册,为宇航员提供更直观的操作指导。本文提出了一种无标记的中国空间站智能维护方法。采用点对特征方法来估计初始帧姿态,不需要手动调整来获得相应的姿态,这对宇航员来说至关重要,因为在微重力环境中精确运动是一项重大挑战,而且结合曲率信息可以提高采用点对特征方法估计初始帧姿态的效率。通过结合纹理和区域信息,消除了对宇航员位置的精确限制,进一步增强了空间对称产品的跟踪鲁棒性。该方法利用点云匹配来估计第一帧的初始姿态,并在失去跟踪后重新计算姿态。一旦获得了前一帧的姿态,则仅根据二维图像的区域和纹理信息来计算跟踪,以获得实时跟踪。实验结果表明:本文方法与基于标识的方法具有相同的姿态趋势;基于电子游标卡尺测量之间的误差在毫米级;使用专门为航天产品设计的专用工具成功更换过滤器,证明了在空间站上实施诱导维修程序的实用性和潜力。

摘要：直径超过2 m的超大型涡轮盘的锻造载荷接近甚至超过了国内最大压力机的极限(800 MN),是真正的极限制造。因此,保持良好的力学性能和控制锻造载荷是超大型涡轮盘热锻生产过程中必须同时兼顾的2个因素。基于田口法设计了25组不同的热锻参数,采用SNR和ANOVA方法对有限元模拟结果进行多目标优化分析,获得了最优锻造载荷和最均匀细化的再结晶组织,确定了极端制造条件下的最佳工艺参数组合(温度1120℃,应变速率0.06 s^(-1),预锻尺寸985/610/475 mm,模具温度280℃)。各参数对模拟结果的重要性顺序如下:变形温度>应变速率>坯料形状>>模具温度。使用最佳参数组合获得的实验结果与数值模拟结果吻合较好,表明该方法可以避免大量实验和数值模拟工作量,有效地控制超大型锻件的载荷和微观组织。