DVB-S信道内码解码器的FPGA实现

采用基于软件流水线的回溯法实现维特比译码中的幸存路径管理,从而有效节省了资源消耗,并提高了译码速度；从DVB-S解码器的整体系统结构考虑,使用一种高效的同步头锁定及内码信息确定的方案。整个设计在Xilinx公司的XC2VP30上实现。     

Scalable Fabrication of Metallic Nanofiber Network via Templated Electrodeposition for Flexible Electronics

Metallic nanofiber networks (MNFNs) are very promising for next‐generation flexible transparent electrodes (TEs) since they can retain outstanding optical and electrical properties during bending due to their ultralong and submicron profile. However, it is still challenging to achieve cost‐effective and high‐throughput fabrication of MNFNs with reliable and consistent performance. Here, a cost‐effective method is reported to fabricate high‐performance MNFN‐TEs via templated electrodeposition and imprint transfer. The fabricated electrodeposition template has a trilayer structure of glass/indium tin oxide/SiO₂ with nanotrenches in the insulating SiO₂ that can be utilized for repeated electrodeposition of the MNFNs, which are then transferred to flexible substrates. The fabricated TEs exhibit excellent optical transmittance (>84%) and electrical conductivity (<0.9 Ω sq^?1) and show desirable mechanical flexibility with a sheet resistance <2 Ω sq^?1 under a bending radius of 3 mm. Meanwhile, the MNFN‐TEs reproduced from the reusable template show consistent and reliable performance. Additionally, this template‐based method can realize the direct patterning of MNFN‐TEs with arbitrary conductive patterns by selective masking of the template. As a demonstration, a flexible dynamic electroluminescent display is fabricated using TEs made by this method, and the light‐emitting pattern is observable from both sides.     

铝液对石墨润湿过程的研究

铝-石墨复合材料制造中的突出问题是铝液与石墨的润湿能力很差,为此大多在工艺上采取措施,如石墨表面喷涂Ti-B,Ni或Cu涂层,或采用流变铸造等。然而这些措施使得工艺复杂、成本提高,因而推广应用受到限制。为改善铝液与石墨的润湿能力,有必要深入研究铝液对石墨的润湿过程。国内外这方面报道甚少,而且所报道的结果差别较大。我们通过长时间的保温试验,仔细地研究了不同温度下铝液对石墨的润湿过程,发现了一些新的现象。     

自聚焦共焦探测系统轴向分辨率的影响因素

从微小内尺度测量角度出发，研究了针孔尺寸、探测器位置、透镜的数值孔径、放大倍率和杂散光等对自聚焦共焦式探测系统轴向分辨率的影响。结果表明，为提高系统的轴向分辨率，需将有效针孔尺寸控制在≤2.5；探测器需配以精密微调整装置以实现横向精确定位；选用差动共焦光路及大数值孔径和大放大倍率的自聚焦透镜，同时，偏振光路的使用将有效的提高系统的信噪比。     

Mechanically Programmable Dip Molding of High Aspect Ratio Soft Actuator Arrays

This work presents multiple methods of creating high aspect ratio fluidic soft actuators that can be formed individually or in large arrays via dip coating. Within this methodology, four strategies are provided to mechanically program the motion of these actuators, including the use of fiber inclusions, gravity, surface tension, and electric fields. The modular nature of this dip coating fabrication technique is inexpensive, easy to modify, and scalable. These techniques are used to demonstrate the fabrication of soft actuators with aspect ratios up to 200:1 and integrated arrays of up to 256 actuators. Furthermore, these methods have the potential to achieve higher aspect ratios and larger array sizes. Operating pressure, curvature, and curling strength tests reveal the design space in which fabrication parameters can be selected to tune the input and output parameters of soft bending actuators. An individual bending actuator made with these methods weighs between 0.15 and 0.5 g, can hold up to 2 N, and can be designed to work in groups to increase curling strength with distributed contact forces. Arrays of these actuators may be useful in atypical grasping and manipulation tasks, fluid manipulation, and locomotion.     

Tuning Interfacial Properties by Spontaneously Generated Organic Interlayers in Top‐Contact‐Structured Organic Transistors

Controlling the interfacial properties between the electrode and active layer in organic field‐effect transistors (OFETs) can significantly affect their contact properties, resulting in improvements in device performance. However, it is difficult to apply to top‐contact‐structured OFETs (one of the most useful device structures) because of serious damage to the organic active layer by exposing solvent. Here, a spontaneously controlled approach is explored for optimizing the interface between the top‐contacted source/drain electrode and the polymer active layer to improve the contact resistance (R_C). To achieve this goal, a small amount of interface‐functionalizing species is blended with the p‐type polymer semiconductor and functionalized at the interface region at once through a thermal process. The R_C values dramatically decrease after introduction of the interfacial functionalization to 15.9 kΩ cm, compared to the 113.4 kΩ cm for the pristine case. In addition, the average field‐effect mobilities of the OFET devices increase more than three times, to a maximum value of 0.25 cm² V^?1 s^?1 compared to the pristine case (0.041 cm² V^?1 s^?1), and the threshold voltages also converge to zero. This study overcomes all the shortcomings observed in the existing results related to controlling the interface of top‐contact OFETs by solving the discomfort of the interface optimization process.     

Conductive Transparent TiNx/TiO2 Hybrid Films Deposited on Plastics in Air Using Atmospheric Plasma Processing

The successful deposition of conductive transparent TiN_x/TiO₂ hybrid films on both polycarbonate and silicon substrates from a titanium ethoxide precursor is demonstrated in air using atmospheric plasma processing equipped with a high‐temperature precursor delivery system. The hybrid film chemical composition, deposition rates, optical and electrical properties along with the adhesion energy to the polycarbonate substrate are investigated as a function of plasma power and plasma gas composition. The film is a hybrid of amorphous and crystalline rutile titanium oxide phases and amorphous titanium nitride that depend on the processing conditions. The visible transmittance increases from 71% to 83% with decreasing plasma power and increasing nitrogen content of the plasma gas. The film resistivity is in the range of ～8.5 × 10¹ to 2.4 × 10⁵ ohm cm. The adhesion energy to the polycarbonate substrate varies from ～1.2 to 8.5 J/m² with increasing plasma power and decreasing plasma gas nitrogen content. Finally, annealing the film or introducing hydrogen to the primary plasma gas significantly affects the composition and decreases thin‐film resistivity.     

Highly Stretchable or Transparent Conductor Fabrication by a Hierarchical Multiscale Hybrid Nanocomposite

As is frequently seen in sci‐fi movies, future electronics are expected to ultimately be in the form of wearable electronics. To realize wearable electronics, the electric components should be soft, flexible, and even stretchable to be human‐friendly. An important step is presented toward realization of wearable electronics by developing a hierarchical multiscale hybrid nanocomposite for highly flexible, stretchable, or transparent conductors. The hybrid nanocomposite combines the enhanced mechanical compliance, electrical conductivity, and optical transparency of small CNTs (d ≈ 1.2 nm) and the enhanced electrical conductivity of relatively bigger Ag nanowire (d ≈ 150 nm) backbone to provide efficient multiscale electron transport path with Ag nanowire current backbone collector and local CNT percolation network. The highly elastic hybrid nanocomposite conductors and highly transparent flexible conductors can be mounted on any non‐planar or soft surfaces to realize human‐friendly electronics interface for future wearable electronics.     

Transparent Soft Robots for Effective Camouflage

Transparency is a surprisingly effective method to achieve camouflage and has been widely adapted by natural animals. However, it is challenging to replicate in synthetic systems. Herein, a transparent soft robot is developed, which can achieve effective camouflage. Specifically, this robot is driven by transparent dielectric elastomer actuators (DEAs). Transparent and stretchable conductive polymers, based on blends of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and water‐borne polyurethane (WPU), are employed as compliant solid‐state electrodes in the DEAs. The electrode exhibits large stretchability, low stiffness, excellent conductivity at large strain, and high transmittance. Consequently, the DEA can achieve a large voltage‐induced area strain of 200% and a high transmittance of 85.5%. Driven by these soft actuators, the robot can realize translations using its asymmetric vibration mode, which can be explained by dynamics analysis and is consistent with finite element modeling. This soft robot can achieve effective camouflage, due to its high transparency as well as thin structure. Furthermore, the robot can become completely flat for even better camouflage by converting its 3D structure to 2D. The transparent soft robot is potentially useful in many applications such as robots for battlefield, reconnaissance, and security surveillance, where effective camouflage is required in dynamic and/or unstructured environments.     

高超音速中波红外窗口材料思考

针对未来高超音速飞行器的发展趋势,阐述了红外窗口材料所面临的技术挑战。从高温透过范围、红外辐射系数、高温力学性能以及抗热冲击等角度分析比较了几种常见的中波红外材料,基于此认为Y2O3陶瓷是未来高超音速中波红外窗口/整流罩的最佳候选材料,该材料能够适应多色、多模复合,超视距、宽视角,以及隐身化和抗电磁干扰等需求。