三线阵立体测绘卫星LMCCD相机的实现

为了降低对卫星姿态稳定度的要求,对全球以及月球、火星等外星球进行无控制摄影测量与制图,在卫星摄影测量中引入LMCCD相机的概念。实现用于立体测绘的LMCCD相机,需要满足技术指标要求的光学镜头、LMCCD像面、调焦机构以及内方位元素。本文根据LMCCD相机的实现条件,对LMCCD探测器的配置、LMCCD像面结构与拼接以及光学镜头、调焦机构进行了详细设计,并对LMCCD相机的内方位元素进行了分析计算。     

基于NFC与Qi的无源电子纸显示设计

传统的电子纸显示装置耗电量大、内容更换繁琐,为增强其便捷性、缩小体积、降低功耗,文中基于LPC824结合近场通信技术与无线充电技术,并配合手机App设计了一款终端无源的电子纸显示装置。将带有NFC功能的手机靠近显示装置,可刷新电子纸上信息,移开手机后,信息可长期保留,且无需电源供电。通过对设计方案进行测试,实验结果验证了该方案的合理性与实用性。     

QoS‐Guaranteed Multiuser Scheduling in MIMO Broadcast Channels

This paper proposes a new multiuser scheduling algorithm that can simultaneously support a variety of different quality‐of‐service (QoS) user groups while satisfying fairness among users in the same QoS group in MIMO broadcast channels. Toward this goal, the proposed algorithm consists of two parts: a QoS‐aware fair (QF) scheduling within a QoS group and an antenna trade‐off scheme between different QoS groups. The proposed QF scheduling algorithm finds a user set from a certain QoS group which can satisfy the fairness among users in terms of throughput or delay. The antenna trade‐off scheme can minimize the QoS violations of a higher priority user group by trading off the number of transmit antennas allocated to different QoS groups. Numerical results demonstrate that the proposed QF scheduling method satisfies different types of fairness among users and can adjust the degree of fairness among them. The antenna trade‐off scheme combined with QF scheduling can improve the probability of QoS‐guaranteed transmission when supporting different QoS groups.     

Mechanically Drawable Thermochromic and Mechanothermochromic Polydiacetylene Sensors

Recently, the development of directly writable techniques for depositing functional materials on solid substrates has received great attention. These pen‐on‐paper approaches enable generation of diverse patterned images on solid substrates in a flexible, easy handling, and inexpensive manner. Herein, the development of a directly writable conjugated polymer is described. Mechanically, drawable colorimetric polydiacetylene (PDA)–wax composites are readily fabricated by using a simple mixing‐molding method. Images are mechanically drawn on a paper substrate using the PDA–wax composites, display thermochromism, and mechanothermochromism. The thermochromic transition temperature is dependent on the melting point of the wax and, as a result, can be precisely controlled by the type of wax used. Optical microscopic analysis shows that formation of the DA–wax composite involves movement of wax molecules into a single diacetylene (DA) crystal. This process results in growth of the crystal. Importantly, the PDA crystal, obtained after UV light irradiation, undergoes significant shrinkage upon heating because of the release of monomers and the embedded wax molecules from the crystal. The release of these molecules creates void in the PDA supramolecules, allowing the PDA chains to undergo C–C bond rotation and hence the blue‐to‐red color transition.     

Au‐Decorated Cracked Carbon Tube Arrays as Binder‐Free Catalytic Cathode Enabling Guided Li2O2 Inner Growth for High‐Performance Li‐O2 Batteries

Owing to their extremely high energy density, Li‐O₂ batteries have attained increasing attention in recent studies. However, deposition of the discharge product, insulating Li₂O₂, is known to seriously limit the electrochemical performance of Li‐O₂ batteries. While extensive studies have focused on relieving electrode deactivation by controlling Li₂O₂ growth, no permanent or effective mechanism is delivered. Here, a unique design comprising a catalytic cathode constructed by cracked carbon submicron tube (CST) arrays decorated with Au nanoparticles on inner walls is proposed. The introduction of Au nanoparticles not only improves electrode conductivity but also provides catalytic sites, guiding conformal growth of thin‐layered Li₂O₂ inside the cracked CST. Density functional theory calculations support that Au decoration on CST favors the conformal growth of Li₂O₂ on inner tubular walls. This growth behavior of Li₂O₂ renders easy decomposition of Li₂O₂, prevents carbon tube electrode from full, rapid deactivation, and preserves the free space for reactants transport. Li‐O₂ cells with Au@CST exhibit good rate capability (1208 mAh g^–1 at a high current density of 1000 mA g^–1) and long cycle life (112 cycles at a current density of 400 mA g^–1 with a limited capacity of 500 mAh g^–1).     

一种汉字报文的数值加密方法

针对汉字信息在公共信道传递的保密要求，研究了汉字在计算机内部的区位码表示形式，提出在信息加密中汉字对用区位码数值进行处理，研究设计了汉字区位码数值加密方式的一种方法，对加密的强度进行了简单分析，并给出了汉字的加密解密流程图和C语言的加密解密程序。     

压力管道内壁打磨机器人的研制

针对工业压力管道内壁存在腐蚀、结垢等情况,会对压力管道内窥镜检测以及介质流动、热量传递等存在不利影响的问题,在国内外管道机器人研究的基础上,设计了一种全新的管道内壁自动打磨装置,对管道内壁打磨机器人进行结构设计,提出了预紧力机构、打磨机构、驱动机构的设计方案。试验结果显示,该打磨机器人具有良好的运行稳定性和弯管过弯性能,并能实现有效打磨,对保障压力管道安全运行具有重要意义。     

管端内衬不锈钢焊管环焊缝缺陷分析

为了对国内某供水工程用管端内衬不锈钢钢管环焊缝缺陷进行评定,利用光学显微镜、扫描电镜以及能谱分析等手段对缺陷形貌、元素含量和组织形态进行了分析。结果表明,该环焊缝缺陷为典型焊接热裂纹,裂纹起始位置在碳钢层底部,裂纹处以淬硬的马氏体组织为主,并伴有氧化物夹杂物。分析认为,该裂纹缺陷是由于打底焊之后焊道保护不良、清理不到位和焊接热输入过大造成,可以通过严格控制有害杂质、降低热输入、减小接头拘束度等方法来防止此类缺陷的发生。     

固化淤泥的持水特性研究

为满足固化淤泥作为土工材料用于施工时施工工艺的要求,研究非饱和固化淤泥的持水能力非常必要。结合离心机法与滤纸法的优势,采用联合测定法获得龄期为56d的固化淤泥的土水特征曲线,从孔隙水转化的角度分析了水泥掺量对固化淤泥持水特性的影响。试验结果表明,固化淤泥的持水特性随水泥掺量的增加而增加;随着水化产物的增多,土水特征曲线的空气进入值不断增大,脱水速率不断减少。     

速度,效率,环保：关于中国造纸工业持续发展的一些思考

本文探讨了在我国经济体制深入改革的新形势下，造纸工业发展的动力与主要制约因素，以及行业持续发展值得重视的一些问题。