电场传感器校准的等效天线系数法

针对电场传感器在1 GHz以上频段高于200 V/m场强的校准需求,提出了等效天线系数法.该方法借用了天线系数的概念,在混响室中首先通过现有场强标准装置传递得到小场强时接收天线的等效天线系数,再利用等效天线系数对混响室中的大场强定标,从而实现电场传感器的大场强校准.混响室中采用等效天线系数法定标的大场强与采用统计方法计算得到的大场强相比较,场强偏差满足系统不确定度要求,说明了等效天线系数法的合理性.该方法借助混响室的特点和天线系数概念,将电场传感器校准幅度提升至200 V/m以上,为大场强测量的准确性提供了依据.     

基于虚拟现实环境的脑机接口技术研究进展

将脑-机接口(brain-computer interface,BCI)技术与虚拟现实(virtual reality,VR)相结合构成基于虚拟现实的脑-机接口(BCI-VR)新技术是最近在多媒体和娱乐领域出现的一种BCI应用新模式。BCI-VR兼取两者优势互补,同时又相互促进创新,显示出广阔应用前景。本文从BCI-VR系统基本构成、BCI对VR控制和VR对BCI影响等方面,较详细介绍了近年来BCI-VR的主要研究方法、研究进展和成就,并根据作者体会小结了目前存在的难点与未来的可能发展动向,以与读者交流、共同促进BCI-VR新技术的快速发展。     

基于粒矩阵的多输入多输出真值表快速并行约简算法

真值表是表征逻辑输入与输出之间因果关系的重要工具,真值表约简在数字逻辑电路的分析与设计中具有重要意义.该文将真值表看作逻辑信息系统,将真值表约简转化为逻辑信息系统的最简规则获取.采用粒计算分层粒化的思想,在不同粒度下,利用粒矩阵的知识表示形式、粒矩阵中的启发式知识以及粒矩阵运算,设计了多输入多输出真值表快速并行约简算法.以发光二极管七段数字显示器为例进行了算法说明,通过数学证明和算法复杂性分析证明了算法的正确性和有效性.     

高清演播室系统搭建初探

本文介绍了河南电视台第一个高清演播室系统600平米高清演播室视频部分的设计原则、总体思路、搭建方案和针对设计方案形成的几个系统特点,论证了各种类型高标清兼容系统的优缺点,并对高清系统在实际使用中可能遇到的问题提出了一些解决经验和改进思路。     

Signal through-the-silicon via planning and pin assignment for thermal and wire length optimization in 3D ICs

Signal through-the-silicon via (STS-via) planning plays an important role in multi-layer nets which need vertical interconnection between different device layers. Moreover, STS-via can also dissipate heat, which is a much more serious problem in 3D ICs than in 2D ICs. Since the through-the-silicon via is large and can only be inserted into whitespace of the device layer, planning STS-via for thermal optimization may affect the interconnection wire length. Therefore, in order to make STS-via planning more flexible, we integrated STS-via with pin assignment. In this paper, we use min-cost maximum flow algorithm for STS-via planning and pin assignment simultaneously. Experimental results show that our approach can reduce both temperature and wire length effectively with short runtime.     

Rate Control Algorithm Considering Mobility in Mobile Ad Hoc Networks

For reducing the loss of data packet due to network congestion and mobility, rate control algorithm is effective means for ensuring the fair allocation of network resource among communication flows and alleviating network congestion. The Transport Control Protocol (TCP) was originally designed for wire-line networks, where the links are assumed to be reliable and with fixed capacities. However, the performance of TCP becomes very poor when it is directly used in ad hoc networks. Some optimization-based congestion control schemes have been proposed to improve TCP performance in ad hoc networks, but the mobility of hosts and route change frequently are not considered for designing rate control algorithm. In this paper, we propose rate control algorithms in a more practical way by taking into account link congestion and node movement. Numerical results show that the rate control algorithms can approach the globally optimal value and show the effect of the node mobility on the algorithms.     

原位法制备通孔AAO模板的原理和工艺

AAO模板是制备纳米材料常用的模板,然而由于阻挡层的存在,制约了其在很多方面的应用.介绍了在不剥离基体的前提下,采用阶梯降压法和反向电压法在原位除去阻挡层,制备通孔的模板.利用场发射扫描电镜对其形貌进行了表征,分析了这两种方法在原位去除阻挡层的原理,讨论了其工艺条件对制备通孔模板的影响,并对其结果进行了比较.结果表明:阶梯降压法能有效减薄阻挡层厚度,通过后续磷酸浸泡能达到在原位除去阻挡层的目的,但是底部孔道出现分叉现象;而反向降压法能在原位有效除去阻挡层,且不破坏模板.     

A Cryo-XPS Study of Triammonium Citrate-KAuCl<Subscript>4</Subscript>-Na<Subscript>2</Subscript>SO<Subscript>3</Subscript> Electroplating Solutions for Pb-Free Solder Packaging

Cyanide-free Au plating baths, containing KAuCl₄, triammonium citrate, and sodium sulfite, have been developed by the authors. The stability of these solutions depends on the order of mixing of the additives. The aim of this study was to employ turbidity measurements and cryogenic x-ray photoelectron spectroscopy (XPS) to identify the role of the additives and the complexes responsible for solution stability or degradation. Electron microscopy was used to characterize any precipitation products generated in the solutions. It was shown that the long-term stability of the solutions is due to the role of citrate and sulfite as complexing agents.     

A Conductive 2D Conjugated Tetrathia[8]circulene-Based Nickel Metal–Organic Framework for Energy Storage

Herein, a novel D₄ symmetrical redox-active ligand tetrathia[8]circulene-2,3,5,6,8,9,11,12-octaol (8OH-TTC) is designed and synthesized, which coordinates with Ni²⁺ ions to construct a 2D conductive metal-organic framework (2D c-MOF) named Ni-TTC. Ni-TTC exhibits typical semiconducting properties with electrical conductivity up to ≈1.0 S m⁻¹ at 298 K. Furthermore, magnetism measurements show the paramagnetic property of Ni-TTC with strong antiferromagnetic coupling due to the presence of semiquinone ligand radicals and Ni²⁺ sites. In virtue of its decent electrical conductivity and good redox activity, the gravimetric capacitance of Ni-TTC is up to 249 F g⁻¹ at a discharge rate of 0.2 A g⁻¹, which demonstrates the potential of tetrathia[8]circulene-based redox-active 2D c-MOFs in energy storage applications.     

应用于流水线模数转换器的快速前后台组合数字校正

本文描述了一种用于流水线模数转换器的快速数字校正技术。所提出的数字校正方法利用了前台和后台校正,可以纠正由于MDAC中电容失配和运放有限增益所产生的非线性。在本文的组合校正算法中,提出了新型带有信号平移相关算法的并行数字后台校正技术,它的校正周期非常短。本文的数字校正方法以一个14位100Msps流水线模数转换器为例。本文的数字后台校正通过三种方式达到高速的收敛速度。首先,提出了改进型1.5位流水线子级,目的是在信号通路中注入大幅值的伪随机抖动信号而不产生失码;其次,在校正级输出信号进行相关运算之前先根据校正级的输入信号范围进行平移,从而使相关运算达到高速的收敛速度;最后,前端流水线子级同时进行校正,而不是逐级进行校正,从而降低数字后台校正周期。仿真结果证明组合校正具有快速的启动过程和非常短的后台校正周期。