Reduction of earthquake risk in the United States: bridging the gapbetween research and practice

Continuing efforts under the auspices of the National Earthquake Hazards Reduction Program are under way to improve earthquake risk assessment and risk management in earthquake-prone regions of Alaska, California, Nevada, Washington, Oregon, Arizona, Utah, Wyoming, and Idaho, the New Madrid and Wabash Valley seismic zones in the central United States, the southeastern and northeastern United States, Puerto Rico, Virgin Islands, Guam, and Hawaii. Geologists, geophysicists, seismologists, architects, engineers, urban planners, emergency managers, health care specialists, and policymakers are having to work at the margins of their disciplines to bridge the gap between research and practice and to provide a social, technical, administrative, political, legal, and economic basis for changing public policies and professional practices in communities where the earthquake risk is unacceptable     

Graphene‐Based Nanomaterials: Synthesis,Properties, and Optical and Optoelectronic Applications

Graphene, a two‐dimensional, single‐atom‐thick carbon crystal arranged in a honeycomb lattice, shows extraordinary electronic, mechanical, thermal, optical, and optoelectronic properties, and has great potential in next‐generation electronics, optics, and optoelectronics. Graphene and graphene‐based nanomaterials have witnessed a very fast development of both fundamental and practical aspects in optics and optoelectronics since 2008. In this Feature Article, the synthesis techniques and main electronic and optical properties of graphene‐based nanomaterials are introduced with a comprehensive view. Recent progress of graphene‐based nanomaterials in optical and optoelectronic applications is then reviewed, including transparent conductive electrodes, photodetectors and phototransistors, photovoltaics and light emitting devices, saturable absorbers for ultrafast lasers, and biological and photocatalytic applications. In the final section, perspectives are given and future challenges in optical and optoelectronic applications of graphene‐based nanomaterials are addressed.     

Recent Advances in Hybridization,Doping, and Functionalization of 2D Xenes

The emerging monoelemental 2D materials named as Xenes including borophene, silicene, germanene, stanene, phosphorene, arsenene, antimonene, bisthumene, selenene, and tellurene, have attracted rising attention experimentally and theoretically. Because of their excellent and versatile physical, chemical, electrical, and optical advantages, Xenes have been shown or have been predicted to have excellent performance in nanotechnology applications, addressing challenges and advances in electronics, energy, healthcare, and environment. In this review, the basic fundamentals in the classification of the periodic table group and the synthesis methods for the emerging materials are summarized. Then, the hybridization, doping and functionalization of 2D Xenes, and their corresponding applications are presented. Furthermore, a summary of research progress on 2D Xenes and the challenges and perspectives for their further development are discussed.     

基于OpenMV的四旋翼无人机目标跟踪系统设计与实现

基于四旋翼无人机小巧便捷可控的特点,设计并实现了一种可识别并自动跟踪物体的四旋翼无人机系统,该系统采用STM32F407为主控芯片,综合光流模块、数传模块、OpenMV4模块和电机、螺旋桨等外围设备,采用姿态估算、色块跟踪解耦合、色块识别、滤波、坐标系转换、PID调节、前馈调节等算法实现四旋翼的识别与自动跟踪,使其可以在平稳飞行的同时,按照程序指令搜寻目标,并触发跟踪状态,完成自动跟踪。该四旋翼无人机系统灵巧便携,操作简单,通用性强,应用前景广阔。     

Open standards for homeland security sensor networks

Sensors and networks are key components in building distributed sensor networks nationwide for detecting weapons of mass destruction and monitoring and protecting critical infrastructure such as airports, bridges, buildings, railways, utility, and water supplies. Tens of thousands of sensors will be connected through wired and wireless networks for communicating and sharing sensor data and information among government agencies and private enterprises to effectively protect people and property. Open, standardized sensor interfaces and sensor data formats are needed to enable effective integration, access, fusion, and use of sensor-derived data in critical homeland security (HLS) applications. This article discusses some open standards that enable rapid and seamless sensor interconnection, integration, discovery, access, and usage within and across systems, networks, and enterprises through Web access.     

基于数字虚拟的工业设计创新模式与应用研究

本文通过数字技术虚拟性的方式、方法、途径的理论性研究,基于数字化技术的多感知性、交互操作性、对现实事物关系、活动、认知的实际模拟性,通过数字技术(如:VR技术、AR技术、3D成像技术等)虚拟工业设计在设计流程、设计管理、制造加工、设计体验、设计服务等事件的实际情景,实现工业设计的设计与制造的多样化信息交互,提高产品设计方案的合理性和可行性,为工业设计设计、制造、研发的创新开辟一种新型的理念与模式。     

Advanced Compressible and Elastic 3D Monoliths beyond Hydrogels

3D monoliths have undergone great progress in the past decades in scientific and engineering fields. Especially, compressible and elastic 3D monoliths (CEMs) hold great promise in a series of applications, such as pressure/strain sensing, energy storage, oil/water separation, and thermal insulation, attributed to their unique mechanical properties and multifunctionality (e.g., conductivity, thermal stability, and high adsorption capacity). Recently, plenty of advanced CEMs have been developed from 1D and 2D building blocks, polymers, and biomass via various methods. Herein, the latest progress in controllable design and preparation of advanced CEMs, which mainly refer to aerogels, sponges, and foams, are reviewed in terms of their structural units and applications. The relationship between structure and mechanical performances of CEMs is discussed. Moreover, their applications in sensing, energy storage and conversion, water treatment, fire‐resistance, and electromagnetic interface shielding are presented. Finally, the challenges and future opportunities of CEMs are also discussed.     

单目图像序列光流三维重建技术研究综述

由单目图像序列光流重建物体或场景的三维运动与结构是计算机视觉、图像处理与模式识别等领域的重要研究内容,在机器人视觉、无人机导航、车辆辅助驾驶以及医学影像分析等方面具有重要的应用。本文首先从精度与鲁棒性等方面对单目图像序列光流计算及三维重建技术近年来取得的进展进行综述与分析。然后采用Middlebury测试图像序列对HS、LDOF、CLG-TV、SOF、AOFSCNN 和 Classic ＋NL 等典型光流算法以及 Adiv、RMROF、Sekkati 和DMDPOF等基于光流的间接与直接重建方法进行实验对比分析,指出各对比方法的优点与不足,归纳各类方法的性能特点与适用范围。最后对利用分数阶微分模型、非局部约束、立体视觉以及深度线索解决亮度突变、非刚性运动、运动遮挡与模糊情况下光流计算及重建模型的局限性与鲁棒性问题进行总结与展望。     

基于区块链的威胁情报共享及评级技术研究

随着计算机和网络技术的快速发展,网络安全事件频发,安全漏洞不断,威胁情报的作用和价值越来越大。基于区块链的开放、共识、自治和去中心、去信任、不可篡改、可追溯等特点,提出了通过区块链技术构建威胁情报信息的区块,包括IP地址信息、域名信息、URL信息、安全事件信息、漏洞信息、威胁情报源可信度、威胁情报源贡献率等;并设计了基于区块链的威胁情报共享和评级系统,给出了相应的基于区块链的威胁情报共享方法和评级方法,可以实现及时有效获取及分析出最新、最有价值的威胁情报信息,从而及时进行防护及应急响应,促进整个威胁情报生态的闭环持续有效开展。     

Cathode-ray-tube phosphors: Principles and applications

Principles and applications of phosphors in cathode-ray tubes are discussed. Among the basic parameters covered are: back-scattering, secondary emission, penetration, electronic transitions, dead voltage and energy, and optical efficiencies. Various relevant aspects of television kinescopes are discussed, including commercially used phosphor characteristics and screening techniques, radar tubes, image tubes, voltage-dependent color displays, flying-spot and beam-indexing tubes, projection, printing, and infrared stimulation systems. Colorimetry and photometry, as applied to phosphors, are discussed, including the CIE and UCS systems.