Analysis of the properties of soft morphological filtering usingthreshold decomposition

We present the properties of soft morphological operations and the new definitions of binary soft morphological operations. It is shown that soft morphological filtering an arbitrary signal is equivalent to decomposing the signal into binary signals, filtering each binary signal with a binary soft morphological filter, and then reversing the decomposition. This equivalence allows problems in the analysis and the implementation of soft morphological operations in real time by using only logic gates for binary signals instead of sorting the numbers. The architectures of logic-gate implementation of soft morphological operations are also presented. Furthermore, unlike standard morphological filters, the soft morphological closing and opening are in general not idempotent. We develop the conditions and properties for a new class of idempotent soft morphological filters     

Hierarchical Carbon Nanotubes with a Thick Microporous Wall and Inner Channel as Efficient Scaffolds for Lithium–Sulfur Batteries

The proposal herein is based on an efficient sulfur host, namely hierarchical microporous–mesoporous carbonaceous nanotubes (denoted as HMMCNT) that feature a thick microporous wall and inner hollow channel. The electrochemical performance of the composite (HMMCNT‐S) is studied systematically at different discharge cut‐off voltages and at varying sulfur content. The cycling behavior in different voltage windows is compared and the highest specific capacity is shown for HMMCNT‐S‐50 in the range of 1.4–2.8 V. These results imply that better energy densities can be achieved by controlling the discharge cut‐off voltage. Moreover, we show that when the sulfur loading is 50% (HMMCNT‐S‐50), the cycling and rate performance is better than that of the composite loaded with 40% sulfur (HMMCNT‐S–40). Benefiting from the attractive hierarchical micro/mesoporous configuration, the obtained hybrid structure not only promotes electron and ion transfer during the charge/discharge process, but also efficiently impedes polysulfide dissolution. More specifically, the electrode can deliver a specific capacity of 558 mA h g^‐1 even after 150 cycles at a high rate of 1600 mA g^‐1 with a decay rate of only 0.13% per cycle. Considering the beneficial structure of these carbon nanotubes, it is very feasible that these structures may also be used in other research fields, including in catalysis, as supercapacitors, in drug‐delivery applications, for absorption, and so on.     

Effective Polysulfide Rejection by Dipole‐Aligned BaTiO3 Coated Separator in Lithium–Sulfur Batteries

Although the exceptional theoretical specific capacity (1672 mAh g^?1) of elemental sulfur makes lithium–sulfur (Li–S) batteries attractive for upcoming rechargeable battery applications (e.g., electrical vehicles, drones, unmanned aerial vehicles, etc.), insufficient cycle lives of Li–S cells leave a substantial gap before their wide penetration into commercial markets. Among the key features that affect the cyclability, the shuttling process involving polysulfides (PS) dissolution is most fatal. In an effort to suppress this chronic PS shuttling, herein, a separator coated with poled BaTiO₃ or BTO particles is introduced. Permanent dipoles that are formed in the BTO particles upon the application of an electric field can effectively reject PS from passing through the separator via electrostatic repulsion, resulting in significantly improved cyclability, even when a simple mixture of elemental sulfur and conductive carbon is used as a sulfur cathode. The coating of BTO particles also considerably suppresses thermal shrinkage of the poly(ethylene) separator at high temperatures and thus enhances the safety of the cell adopting the given separator. The incorporation of poled particles can be universally applied to a wide range of rechargeable batteries (i.e., metal‐air batteries) that suffer from cross‐contamination of charged species between both electrodes.     

Study on authority watermark of the electronic chart based on the semantics characteristics

In order to expand the function of watermarking technology, a concept of authority watermark, for which, wa-termarks defining the users' specific operations on the digital carriers was proposed. With interception technology on im-ages, the constructed authority watermark based on the semantics characteristics of the watermark images, through the interpretation of the watermarks, accessing behaviors on the electronic chart would be controlled. Experimental results show that, this method can realize safety distribution and operation verification under the network environment, espe-cially with outstanding performance in tamper resistant and forgery.     

Throughput Optimization via Association Control in Wireless LANs

With the rapid development of the mobile computing, accessing the Internet everywhere is important for mobile device users. Wireless LAN is a stable and reliable technique to provide network access for mobile devices. The Wireless LAN Access Points(APs) have been densely deployed so that a user can access the Internet almost everywhere. However, this fact brings some new challenges. Since the regular AP association strategy is signal-based when a user receive the signals of multiple APs. The APs with strong signal will be too overloaded while the bandwidth resource in other APs is wasted. The throughput of the whole WLAN is not optimized. Moreover, the diverse bandwidth demands among users further exacerbate the situation. In this paper, aiming at optimizing the throughput over the whole WLAN, a joint AP association and bandwidth allocation problem is formulated. The different users’ bandwidth demands are added as new constraints. We comprehensively analyze the solution space and prove the problem NP-hard. Our trace-driven evaluations show that the throughput is improved about 23.1 % compared to the conventional schemes.     

飞行品质模拟器设计

飞行品质模拟器是现代先进飞机飞行控制及飞行品质设计验证的一个重要系统设备,论述了飞行模拟器的主要功能和总体构成,介绍了飞机数学模型、座舱虚拟仪表显示、人感系数特性及系统集成等关键技术环节的设计。     

微机在35KV以下线路保护中的运用

本文介绍了基于PC-104微机保护平台,距离保护采用长短数据窗相结合的快速傅立叶算法,对短数据窗采用N取R方法,提高保护的可靠性,兼顾了继电保护速动性和可靠性的要求,有效性和可靠性得到了验证。此方案动作速度快,可靠性高,完全满足35kV以下线路保护的各项需要。     

WiMax近场干扰对UWB系统特性影响的仿真研究

研究了超宽带（UWB）无线通信系统抗WiMax系统的近场电磁干扰能力,为此,首先构建了包括UWB系统和WiMax近场电磁干扰等效的分析模型;其次,基于该分析模型研究了WiMax近场干扰对IEEE 802.15a UWB系统接收灵敏度的影响,得到了在给定场景和WiMax系统参数条件下,UWB系统接收灵敏度的回退量ΔS与其传输速率的关系曲线模型。该关系曲线模型对UWB＋WiMax双模系统共存设计具有重要的理论指导意义。     

海上蒸发波导条件下电波传播的分析

抛物方程方法已经被广泛地应用于电磁波传播的研究,并成为解决电磁波传播问题主要的工具。应用抛物方程和电波传播的基本理论,计算了电磁波在蒸发波导和标准大气中的传输损耗,得到了电波的空间传播损耗图,与射线理论的射线描迹技术得到的结论是一致的,但是抛物方程方法求解速度快,具有很好的实时计算特性,并且能弥补目前射线描迹技术尚不能精确描述空间场分布的缺点,因此更具有实用价值。     

Ka 波段和差馈电网络设计

介绍了一种Ka 波段和差馈电网络,由四级T 形功分器、魔T 级联形成。采用缝隙耦合的方式大大减小了横向与纵向尺寸,满足了天线整体小尺寸的要求。通过HFSS 仿真优化,其输入端口的驻波系数小于1.14,与天线联合仿真和误差分析表明此馈电网络在加工精度内性能稳定,实测结果表明天线各项指标均得到满足。