基于有向拓扑势的用户角色分析方法

真实世界中存在大量有向、加权、动态的网络。针对有向加权网络的节点角色分析问题,提出了一种基于有向拓扑势的节点角色分析方法,该方法根据节点的行为模式及局部影响力将节点划分成4种角色。然后介绍了基于节点角色的动态网络演化分析方法,它能对角色行为进行动力学建模,展示了随时间连接模式的变化,并能检测较大影响的事件。实验结果表明,本方法能有效估计节点角色并检测动态网络的演化。     

Kitkaite NiTeSe,an Ambient-Stable Layered Dirac Semimetal with Low-Energy Type-II Fermions with Application Capabilities in Spintronics and Optoelectronics

The emergence of Dirac semimetals has stimulated growing attention, owing to the considerable technological potential arising from their peculiar exotic quantum transport related to their nontrivial topological states. Especially, materials showing type-II Dirac fermions afford novel device functionalities enabled by anisotropic optical and magnetotransport properties. Nevertheless, real technological implementation has remained elusive so far. Definitely, in most Dirac semimetals, the Dirac point lies deep below the Fermi level, limiting technological exploitation. Here, it is shown that kitkaite (NiTeSe) represents an ideal platform for type-II Dirac fermiology based on spin-resolved angle-resolved photoemission spectroscopy and density functional theory. Precisely, the existence of type-II bulk Dirac fermions is discovered in NiTeSe around the Fermi level and the presence of topological surface states with strong (≈50%) spin polarization. By means of surface-science experiments in near-ambient pressure conditions, chemical inertness towards ambient gases (oxygen and water) is also demonstrated. Correspondingly, NiTeSe-based devices without encapsulation afford long-term efficiency, as demonstrated by the direct implementation of a NiTeSe-based microwave receiver with a room-temperature photocurrent of 2.8 µA at 28 GHz and more than two orders of magnitude linear dynamic range. The findings are essential to bringing to fruition type-II Dirac fermions in photonics, spintronics, and optoelectronics.     

基于节点的地域通信网抗毁性评价及应用

分析了战场条件下地域通信网抗毁性评价的需求和现有地域通信网抗毁性评价方法存在的不足,确定了节点失效条件下地域通信网抗毁性评价的标准和计算流程。从节点失效的实际出发,给出了节点重要度的分析方法,并以该方法为基础,综合考虑节点逐个失效的整个过程,给出了基于节点的地域通信网抗毁性评价方法。最后,将这种方法应用于地域通信网拓扑优化,并给出了应用实例。     

2.5D硅转接板TSV结构研究

针对结构参数对TSV可靠性影响不明确的问题,文中采用有限元分析和模型简化的方法,分析了TSV结构在温度循环条件下的应力应变分布,并进一步研究了铜柱直径、SiO₂层厚度以及TSV节距等结构参数对TSV结构可靠性的影响。结果表明,采用文中的方法简化模型后得出的结果拟合度在0.95以上;在TSV结构上施加温度循环载荷时,在SiO₂界面会出现应力集中,而在钝化层中会出现应变增大;改变铜柱直径、绝缘层厚度和TSV节距将显著影响TSV结构的可靠性;减小填充铜的直径、增加SiO₂层的厚度、增加TSV节距,都将有助于减小TSV结构的最大应力。     

基于拓扑法的分离面检测和可视化

分析与时间相关二维矢量场可视化的拓扑法,并针对分离面检测过程中,流面积分的不连续以及映射的离散,进行改进.首先运用Sobel算子检测种子曲线,然后对检测到的种子曲线进行积分,从而检测到分离面.实验结果显示该方法对分离面的检测更加快速、精确.     

Ultrathin Sticker‐Type ZnO Thin Film Transistors Formed by Transfer Printing via Topological Confinement of Water‐Soluble Sacrificial Polymer in Dimple Structure

To create ultrathin sticker‐type electronic devices that can be attached to unconventional substrates, it is highly desirable to develop printable membrane‐type electronics on a handling substrate and then transfer the printing to a target surface. A facile method is presented for high‐efficiency transfer printing by controlling the interfacial adhesion between a handling substrate and an ultrathin substrate in a systematic manner under mild conditions. A water‐soluble sacrificial polymer layer is employed on a dimpled handling substrate, which enables the topological confinement of the polymer residue inside and near the dimples during the etching and drying processes to reduce the interfacial adhesion gently, creating a high yield of transfer printing in a deterministic manner. As an example of an electronic device that was created using this method, a highly flexible sticker‐type ZnO thin film transistor was successfully developed with a thickness of 13 μm including a printable ultrathin substrate, which can be attached to various substrates, such as paper, plastic, and stickers.     

Feature Detection and Simplification of 3D Face Data with Facial Expressions

We propose an efficient framework to realistically render 3D faces with a reduced set of points. First, a robust active appearance model is presented to detect facial features in the projected faces under different illumination conditions. Then, an adaptive simplification of 3D faces is proposed to reduce the number of points, yet preserve the detected facial features. Finally, the point model is rendered directly, without such additional processing as parameterization of skin texture. This fully automatic framework is very effective in rendering massive facial data on mobile devices.     

基于STL数据模型动态拓扑重构的快速切片算法

分析了现有金属激光立体成形(MLSF)切片算法,提出了一种基于STL模型动态拓扑重构的快速切片算法.根据STL模型中三角面片的几何信息和切片厚度,通过建立分组矩阵,减小了三角面片遍历的次数;通过构建三角面片之间的局部动态拓扑关系,减小了切片平面与三角面片的求交计算次数;并根据切片过程中大部分三角面片的毗邻关系不发生改变这一事实,提出了动态拓扑重构的算法,减小了切片过程中三角面片毗邻关系的查找次数,从而提高了切片算法的整体效率.在该算法的基础上,使用Visual C 和OpenGL开发了金属激光立体成形软件系统.     

Electric‐Field‐Controlled Alignment of Rod‐Shaped Fluorescent Nanocrystals in Smectic Liquid Crystal Defect Arrays

Periodic micro‐arrays of straight linear defects containing nanoparticles can be created over large surface areas at the transition from the nematic to smectic‐A phase in a nanoparticle–liquid crystal (LC) composite material confined under the effect of conflicting anchoring conditions (unidirectional planar vs normal) and electric fields. Anisomeric dichroic dye molecules and rod‐shaped fluorescent semiconductor nanocrystals (dot‐in‐rods) with large permanent electric dipole and high linearly polarized photoluminescence quantum yield align parallel to the local LC molecular director and follow its reorientation under application of the electric field. In the nano‐sized core regions of linear defects, where the director is undefined, anisotropic particles align parallel to the defect whereas spherical quantum dots do not show any particular interaction with the defect. Under application of an electric field, ferroelectric semiconductor nanoparticles in the core region align along the field, perpendicular to the defect direction, whereas dichroic dyes remain parallel to the defect. This study provides useful insights into the complex interaction of anisotropic nanoparticles and anisotropic soft materials such as LCs in the presence of external fields, which may help the development of field‐responsive nanoparticle‐based functional materials.     

Topologically Optimized Fingerless Versatile Gripper Actuated by a Shape Memory Alloy Coiled Garter Spring

The rapid advancements in 3D printing technologies offer immense design flexibility and the ability to create complex structures with high resolution. Using these cutting-edge technologies and materials (i.e., a polylactic acid and fused deposition modeling), a novel design principle is introduced for a fingerless gripper, achieved through topological optimization. To realize the grasping capabilities, a coiled garter spring made of shape memory alloy (SMA) is incorporated at the end of the flexure beams. Based on the experiments, it is found that the gripper is very quick to respond, taking only 5 s to heat up and 15 s to cool down. This promising performance is achieved by carefully balancing the net force differential between the restoring force of the flexure beam and the force of the SMA coiled garter spring. In addition to its responsiveness, the gripper demonstrates a high force-to-weight ratio of 5.3, allowing it to lift heavy payloads of up to 4.91 N (0.5 kgf) despite its lightweight design (total weight of 94.2 g). Overall, this work showcases the potential of 3D printed fingerless grippers in terms of high holding strength, lightweight, low cost, and simple fabrication.