对称非线性包层平板多量子阱波导TE模的传播特性

分别用精确计算和方均根近似方法得到了包层及衬底均为非线性Ｋｅｒｒ型介质、芯区为多量子阱的对称平板波导中ＴＥ模的传播特性。数值计算表明,当芯区多量子阱的层数较多时,方均根近似方法得到的结果与用精确方法得到的结果一致,此时多量子阱波导可以等效为均匀介质。对于自聚焦情况,在合适的光功率下,当分界面处包层（及衬底）的有效折射率与芯区折射率相等时,芯区的场分布呈均匀分布而两侧的场呈指数式衰减;功率继续增大时,场分布的极值进入芯区两侧,而芯区场分布呈下凹形。对于自散焦情况,波导对导波场有较强干线性波导的束缚作用,且随光功率的增大而增强。     

Spectrum leasing based on Nash Bargaining Solution in cognitive radio networks

Cognitive radio is becoming an emerging technology that has the potential of dealing with the stringent requirement and scarcity of the radio spectrum resource. In this paper, we focus on the dynamic spectrum access of cognitive radio networks, in which the primary user (PU) and secondary users (SUs) coexist. In property-rights model, the PU has property of the bandwidth and may decide to lease it to secondary network for a fraction of time in exchange for appropriate remuneration. We propose a cooperative communication-aware spectrum leasing framework, in which, PU selects SUs as cooperative relays to help transmit information, while the selected SUs have the right to decide their payment made for PU in order to obtain a proportional access time to the spectrum. Then, the spectrum leasing scheme is cast into a Nash Bargaining Problem, and the Nash Bargaining Solution (NBS) can be used to fairly and efficiently address the resource allocation between PU and secondary network, enhancing both the utility of PU and secondary network. Numerical results show that spectrum leasing based on NBS is an effective method to improve performance for cognitive radio networks.     

基于前向多层神经网络的分组码译码器设计

把最大相关译码与神经网络神经元的内积特性及吸引域有机地联系起来,连接权决定译码码字,阈值设定决定神经元的纠错范围,从而形成一种可用于硬判决及软判决译码的神经译码器,并在理论上证明了此译码器可在ＤＭＣ信道的纠错能力范围内实现零错误概率硬判决译码,也可实现与最小欧几里德距离译码相当的软判决译码,并能在检错范围内检错。     

一种用来测量低层大气温湿度结构的高精度探空仪

本文报道了我们研制的高国湿度探空仪,用薄陶瓷片型铂电阻测量气温、用干湿球法测量湿度,并采用参考电阻克服频漂,从而保证了测量精度,能精确测量出大气边界层温湿度结构。     

基于GE交换的Gpbs无线传输平台ARQ算法的研究

基于千兆以太网（GE）交换的无线传输平台结构较之传统软件无线电平台具有强大的可编程能力和良好的可扩展性,配合多入多出-正交频分复用（MIMO-OFDM）技术,可实现达到1 Gb/s吞吐率（Gbps）的无线传输系统,针对Gbps高速无线传输的需求与平台特性,提出了一种自动重传请求（ARQ）机制,结合平台的结构特点,针对系统需求,在保证无线传输可靠性的前提下减小ARQ机制对传输吞吐率的开销,并可通过参数的优化适应于不同的应用场景。     

频率捷变雷达信号源边工作边校准技术研究

分析了原有频率捷变雷达信号源中频率校准方法存在的缺陷，在此基础上设计了边工作边校准的频率校准电路，提高了信号源的频率跟踪精度和稳定工作时间。     

石油钻机的变频改造

本文以大庆油田石油管理局井下作业分公司配备的风光JD-BP32-500型石油钻机变频器为例，介绍了石油钻机进行变频改造的意义、应用效果及使用价值。由于石油钻机的特殊的应用环境，在变频器的产品设计方面注意到了相关的技术难点，为该类广品的开发提供了相关的依据。     

Achieving Both High Voltage and High Capacity in Aqueous Zinc‐Ion Battery for Record High Energy Density

In this work, a high‐voltage output and long‐lifespan zinc/vanadium oxide bronze battery using a Co_0.247V₂O₅?0.944H₂O nanobelt is developed. The high crystal architecture could enable fast and reversible Zn²⁺ intercalation/deintercalation at highly operational voltages. The developed battery exhibits a high voltage of 1.7 V and delivers a high capacity of 432 mAh g^?1 at 0.1 A g^?1. The capacity at voltages above 1.0 V reaches 227 mAh g^?1, which is 52.54% of the total capacity and higher than the values of all previously reported Zn/vanadium oxide batteries. Further study reveals that, compared with the pristine vanadium oxide bronze, the absorption energy for Zn²⁺ increases from 1.85 to 2.24 eV by cobalt ion intercalation. Furthermore, it also shows a high rate capability (163 mAh g^?1 even at 10 A g^?1) and extraordinary lifespan over 7500 cycles, with a capacity retention of 90.26%. These performances far exceed those for all reported zinc/vanadium oxide bronze batteries. Subsequently, a nondrying and antifreezing tough flexible battery with a high energy density of 432 Wh kg^?1 at 0.1 A g^?1 is constructed, and it reveals excellent drying and freezing tolerance. This research represents a substantial advancement in vanadium materials for various battery applications, achieving both a high discharge voltage and high capacity.     

Low-latency neighbor discovery algorithm based on multi-beacon message in mobile low-duty-cycle sensor network

Neighbor discovery enables nodes in the networks to discover each other through simple information interaction,which was suitable for the new mobile low duty cycle sensor network (MLDC-WSN).However,because the nodes in MLDC-WSN can move randomly and sleep,the network topology was changed frequently,which results in that some nodes need a lot of energy and time to find their neighbors.How to realize fast neighbor discovery for all nodes in the network was a difficult problem in current research.To solve this problem,a new low-latency neighbor discovery algorithm based on multi-beacon messages was proposed.In this algorithm,the nodes were discovered by sending a short beacon message through their neighbor nodes,and by adjusting the time and frequency of beacon message sent,a lower neighbor discovery delay was obtained.Eventually,through quantitative analysis and simulation experiments,it is found that compared with existing algorithms,this algorithm can find all neighbor nodes in MLDC-WSN with less energy consumption,lower latency and greater probability.     

超高斯加载的稳健自适应波束形成及性能分析

该文提出了一种超高斯加载的稳健自适应波束形成方法,解决由于导向矢量和样本方差矩阵失配误差所导致的波束形成器性能下降的问题,利用p-范数来对两种误差不确定性进行总体修正,克服了2-范数不能同时兼顾两者实现最优修正的缺点。采用遗传算法求得最优范数p,验证了在不同实验设置下,当使用最优范数时,都比2-范数约束具有更好的性能。超高斯加载方法把复杂的不确定性建模问题转化为范数p的寻优问题,从而获得比对角加载方法更优异的性能。