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71.
72.
Xizheng Liu Wenqing Ma Xiaofeng Lei Shichao Zhang Yi Ding 《Advanced functional materials》2020,30(28)
Rechargeable metal–SO2 batteries have drawn tremendous attention because it can accelerate SO2 fixation/utilization and offer high energy density. Herein, a rechargeable Na–SO2 battery based on an ether‐based liquid electrolyte with an ethylenediamine (EDA) additive is realized via the reversible formation/decomposition of Na2S2O4. Experimental investigations reveal that the EDA additive provides three benefits by simultaneously decreasing the overall electrode polarization, increasing the full discharge capacity, and improving battery cyclability. At a current density of 250 mA g?1, the full discharge capacity of the battery with the EDA additive is more than twice of a similar system in the absence of EDA. In addition to the significantly enhanced capacity, the as‐assembled Na–SO2 battery demonstrates excellent cyclic stability after 200 cycles, which is equivalent to a total duration of 1600 h. Moreover, the corrosion resistance of Na anode is strengthened with the aid of EDA in the SO2‐containing liquid electrolyte. This work will pave the way for Na–SO2 batteries as a promising battery technology toward both pollutant gas utilization and energy storage. 相似文献
73.
针对大气激光通信中由大气湍流引起的系统性能下降问题,研究了基于物理层自适应调制编码(AMC)和数据链路层混合自动请求重传(HARQ)的大气激光通信跨层系统性能。在建立了大气湍流信道瞬时信噪比模型的基础上,建立了大气激光通信AMC-HARQ系统模型,并推导了系统误包率和频带利用率公式,最后在双伽马信道模型下进行了仿真分析。仿真结果表明,大气激光通信AMC-HARQ系统能够在保证一定误包性能的条件下,大大提高系统频带利用率,提高单一应用AMC时的系统误包性能。随着重传次数增加,误包率和频带利用率均提高,但频带利用率增幅随重传次数增加而减小。 相似文献
74.
针对信息系统遗留系统的综合集成问题,分析系统需求,研究资源共享的集成目标。围绕该目标总结分析了当前信息系统集成的多种集成策略和方案,结合软件技术发展,提出了面向资源共享的信息系统集成总体框架。通过统一管理软件资源,提供资源访问统一门户,采用面向服务架构(SOA)理念基于消息总线的技术体制实现软件资源分布共享及信息交互。 相似文献
75.
针对实时系统记录数据会引起系统运行速度缓慢、瘫痪、甚至"死机"的问题,提出了具有特色的令牌漏桶法。该方法通过创建循环队列数据池并根据数据池的数据量适时发放令牌和拥有令牌的任务自动选择CPU空闲时执行等技术实现。通过试验验证,在保证整个系统实时性、可靠性的前提下,该方法实现了实时记录数据的功能。 相似文献
76.
高校图书馆面对时代的发展,规划文献信息资源的组织和发展的模式,展现出了高校图书馆中的数字化及网络化信息资源的利用和开发管理,这一项目目前成为高校图书馆中急需探究的课题. 相似文献
77.
78.
A new satellite communication bandwidth allocation combined services model and network performance optimization 下载免费PDF全文
Wenliang Lin Zhongliang Deng Qin Fang Ning Li Ke Han 《International Journal of Satellite Communications and Networking》2017,35(3):263-277
With the rapid development of online to offline economy, new services compositions would take up a great part in the satellite communication. More and more new services compositions request more bandwidth and network resources, which lead to serious traffic congestion and low channel utilization. Suffering from isolated link connection and changeable delay under the satellite environment, current bandwidth allocation schemes could not satisfy with the demand of low delay and high assess rate for new satellite services. This paper focuses on bandwidth allocation method for satellite communication services compositions. The novel models of services compositions with single‐hop Poisson distribution are designed to simulate original traffic arrival. Isolated independent coefficients take an original distribution to adapt to isolated disconnections. Services queue waiting time would be judged by acceptable delay threshold. Models provide new services compositions with more precise arrival distributions. In order to improve traffic congestion, the method combined services models, and a network performance is proposed. Optimal reserved bandwidth is set according to the priority and arrival distribution of different services compositions, which classify services with feedback transmission performance. We design minimum fuzzy delay tolerant intervals to calculate delay tolerant threshold, which adapt random delay changes in the services network with delay tolerant features. The simulation in OPNET demonstrates that the proposed method has a better performance of queuing delay by 16.3%, end‐to‐end delay by 18.7%, and bandwidth utilization by 13.2%. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
79.
非结构化P2P网络中稀缺资源的共享机制 总被引:1,自引:0,他引:1
非结构化P2P文件共享网络的应用日益广泛,当前的网络流量主要来自于此类网络中对各类文件资源的搜索。但是目前的搜索机制只适合获取流行资源,存在于个别节点上的稀缺资源很难被搜索到,而用户获取稀缺资源的收益并不小于流行资源,因此高效的搜索命中率将明显提高整个P2P网络的实用性。该文提出一种简单的分布式算法NLIR,使稀缺资源可以像流行资源一样具有较高的搜索命中率。新算法根据度数不同的节点,其处理查询的能力,存储能力,搜索命中率各不相同的特点将稀缺资源的索引副本均匀地扩散到网络中,体现了负载均衡的特性,并且在带宽费用和存储费用都有限的约束条件下,实现了稀缺资源高效的搜索命中率。 相似文献
80.
A novel limited feedback for interference alignment algorithm was proposed based on the disadvantages of traditional limited feedback interference alignment schemes for MIMO uplink.Unlike the traditional linear interference alignment,an iterative scheme was presented.The pre-coder was designed through maximizing the target signal to the interference leakage and noise ratio,and interference suppression matrix was designed by maximizing the signal to interference plus noise ratio for each data stream,which can come over rate loss in low SNR.In addition,the bit allocation of traditional limited feedback schemes were based on the mean of interference leakage,which were not perfect and make the total number of the effective bits less than the bits provided by system.Thus,a novel bit allocation scheme was provided that improving bit utilize and decreasing quantization error.Theoretical analysis and simulation experiments show that compare to the existed classical algorithms,the algorithm was a stepwise enhancement of signal quality for iterative search in perfect CSI which was better than linear algorithm and has a larger space with no need for strictly align interference in limited feedback CSI which reduces the influence of quantization error more.The effective bit distribution and bit utilization are improved by bit allocation,resulting in improved performance in limited feedback. 相似文献