新型雷达波吸收材料研究进展

综述了国内外新型雷达波吸收材料的研究进展 ,根据雷达波吸收材料的吸波机理 ,详细介绍了纳米吸波材料、宽频谱吸波材料、手性吸波材料、导电高分子吸波涂料、结构吸波材料、多晶纤维吸波涂料、电路模拟吸波材料及等离子体吸波材料的最新研究现状。     

Freezing as a Path to Build Micro-Nanostructured Icephobic Coatings

Superhydrophobic photothermal materials with the micro-nano structure are considered to be promising icephobic surfaces. Unfortunately, converting micro-nano hierarchical structure concepts into genuine synthetic materials has proven to be exceedingly expensive and difficult, partially because their sophisticated structures need construction at several length scales. Herein, a facile strategy of employing ice crystals to construct sophisticated hierarchical micro-nanostructured anti-icing composites with photothermal, self-healable, and self-cleaning properties is presented. The composites are covered with interconnected microscale pores replicated from ice crystals, which facilitates the construction of the hydrophobic or superhydrophobic properties based on the Cassie–Baxter model, endowing the coating with self-cleaning ability. Besides, by adding solar-to-heat conversation nanomaterials, the coating can implement in situ solar anti-/deicing. The abundant micropores caused by ice templates can further improve the photothermal conversion capability through multiple reflections of light. Importantly, the coating is endowed with the self-healing capability to repair hydrophobicity under sunlight. Additionally, it is demonstrated that the self-cleaning and self-healing abilities are mutually reinforcing, synergistically improving anti-/deicing performances. Overall, the presented ice-templated coating shows great potential and broad impacts owing to its inexpensive component materials, simplicity, eco-friendliness, and high energy efficiency.     

Scavenging of “Dead Sulfur” and “Dead Lithium” Revealed by Integrated–Heterogeneous Catalysis for Advanced Lithium–Sulfur Batteries

The simultaneous engineering of sulfur cathode and Li anode is critical for electrolyte-starved high energy density Li–S batteries, in which slow electrochemical conversions and side chemical reactions of dead sulfur are found to be the determining factors in limiting the sulfur utilization, corresponding to the poor reversible capacity of Li–S batteries. Herein, this work challenges the conventional wisdom of heterogeneous and homogeneous catalyses in Li–S batteries and proposes the concept of integrated–heterogeneous catalysis to simultaneously scavenge the dead sulfur and dead lithium to compensate the active materials sulfur and lithium loss simply through adding a small amount of ZnI₂ into conventional electrolyte of Li–S cells. Regulated by integrated–heterogeneous catalysis, over 1300 h of cycling is realized in Li||Li symmetric cells, revealing superb compatibility of the ZnI₂-incorporated electrolyte with lithium metal. Meanwhile, the ZnI₂ shows good prospects in promoting the reutilization of dead sulfur in both theoretical calculation and experimental tests. Practically, a high initial capacity of 1170 mAh g⁻¹ with decent cycling stability is achieved in electrolyte-starved and high-loading pouch cells (5.0 µL mg⁻¹ and 5.2 mg cm⁻²).     

捷联惯性测量组合的冗余设计和优化

讨论了捷联惯性测量组合冗余设计方案,并引入性能指标函数、系统有效度约束、系统代价函数,对冗余配置的优化问题进行了研究,寻求最优配置和优化准则.最后以5个单自由度陀螺为例,实现冗余优化配置.     

面向景象匹配制导的图像灰度校正问题研究

基准图匹配性能是影响景象匹配精度的关键因素之一.在分析灰度级线性变换法及灰度直方图均衡化的基本思路基础上, 实现了对基准图的灰度校正处理, 通过可匹配性度量参数分析及匹配仿真实验, 验证了灰度校正在改善基准图匹配性能中的实用意义.     

社交媒体中转基因食品的媒介框架研究——基于美国YouTube视频网站的案例分析

社交媒体在科学传播中扮演的角色日益重要,在促进争议科学题材的传播中发挥的作用尤为显著。本文以世界上最大的社交视频网站You Tube中的转基因食品短片为案例,从传播主体、媒介框架和传播技巧三方面来分析社交媒体的框架建构过程。研究发现,在You Tube网站上美国的各种社会组织抢占了绝对的话语主导权,媒体也有积极参与,而政府和科研机构基本处于失语状态。在媒介框架上,最多的一类是关于食品安全、经济和科技的话题,且大部分都具有负面属性。在塑造技巧上,最受欢迎的短片大部分具有刺激性标题、诉诸于情感和特定价值、制造矛盾吸引受众三个显著特点。     

基于IEEE802.16d系统的简易信道估计算法

提出了基于IEEE802.16d标准的当信道的响应大于循环前缀(CP)时一种简易的信道估计算法。利用系统前导的特殊时域结构,在不增加系统实现复杂度的基础上就可以很好地消除由于循环前缀不足而带来的ICI和ISI的干扰。仿真结果表明该方法可以满足IEEE802.16d在高速非视距环境下对信道估计的性能要求,该研究结果对高传输速率的信道信息估计有较大的参考价值。     

飞行训练视频记录系统的设计

与广泛流行的PCI总线相比,PCIe总线不仅硬件接口简单,软件和PCI完全兼容,而且速度数十倍于PCI,已经开始应用于航空电子系统中.文章介绍了PCIe总线在航空飞行试验视频采集中的应用,给出了硬件接口设计、逻辑设计和软件设计.在航电系统通讯设计中极具有典型性和实用性.     

High-speed low-power voltage-programmed driving scheme for AMOLED displays

A new voltage-programmed driving scheme named the mixed parallel addressing scheme is presented for AMOLED displays, in which one compensation interval can be divided into the first compensation frame and the consequent N-1 post-compensation frames without periods of initialization and threshold voltage detection. The proposed driving scheme has the advantages of both high speed and low driving power due to the mixture of the pipeline technology and the threshold voltage one-time detection technology. Corresponding to the proposed driving scheme, we also propose a new voltage-programmed compensation pixel circuit, which consists of five TFTs and two capacitors(5T2C). In-Zn-O thin-film transistors(IZO TFTs) are used to build the proposed 5T2C pixel circuit. It is shown that the non-uniformity of the proposed pixel circuit is considerably reduced compared with that of the conventional 2T1C pixel circuit. The number of frames(N) preserved in the proposed driving scheme are measured and can be up to 35 with the variation of the OLED current remaining in an acceptable range. Moreover, the proposed voltage-programmed driving scheme can be more valuable for an AMOLED display with high resolution, and may also be applied to other compensation pixel circuits.