Delayed Fluorescence Emitter Enables Near 17% Efficiency Ternary Organic Solar Cells with Enhanced Storage Stability and Reduced Recombination Energy Loss

Charge transfer state (CT) plays an important role in exciton diffusion, dissociation, and charge recombination mechanisms. Enhancing the utilization and suppressing the recombination process of CT excitons is a promising way to improve the performance of organic solar cells (OSCs). Here, an effective method is presented via introducing a delayed fluorescence (DF) emitter 3,4‐bis(4‐(diphenylamino)phenyl)acenaphtho[1,2‐b]pyrazine‐8,9‐dicarbonitrile (APDC‐TPDA) in OSCs. The long‐lifetime singlet excitons on APDC‐TPDA can transfer to polymer donors to prolong exciton lifetime, which ensures sufficient time for diffusion and dissociation. Concurrently, the high triplet energy level (T₁) of the DF material can also prevent the reverse energy transfer from CT to T₁. APDC‐TPDA‐containing ternary OSCs shows a high PCE of 16.96% with a reduced recombination energy loss of 0.46 eV. It is noteworthy that the ternary OSC also exhibits superior storage stability. After 55 days of storage, the PCE of the ternary OSC still retains about 96% of its primitive state. Furthermore, this ternary strategy is efficient and universally applicable to OSCs, and positive results can be obtained in different systems with different DF emitters. These results indicate that the ternary strategy provides a new design idea to realize high performance OSCs.     

基于FPGA的HDB3编译码

主要分析NRZ(单极性不归零码)码与HDB3码(三阶高密度双极性码)之间的转换原理,并介绍了用FPGA(现场可编程门阵列)完成HDB3编译码器的设计思路。     

基于节点持续传输准则的认知传感器网络信道分配策略

在异构分级式认知传感器网络中,为提高数据分组的传输成功率,提出将节点划分为具备持续传输条件和不具备持续传输条件两类,两类节点分别以牺牲较多能耗和分配较优信道的方式提高数据分组的传输成功率,并由此得到一种集中式信道分配策略.为了降低节点在信息传输过程中每比特平均能耗,对数据分组自适应调节机制进行了优化,确保不具备持续传输条件的节点得到最优的传输数据分组大小.仿真结果证明,提出的分配策略和优化机制能够有效提高能量的使用效率,改善网络性能.     

车联网中基于联盟合作博弈的带宽分享策略

近几年来,车联网领域快速发展并引起广泛关注.在此背景下提出了一种混合Wi-Fi、WiMAX和3G/LTE的网络架构,在这种架构下,车辆可以根据自身的情况选择合适的方式接入网络.网络带宽分享采用基于联盟合作博弈的方式,车辆可以选择加入或离开合作联盟来最大化自身收益.模型从理论上证明了通过车辆间的效用分配与博弈合作,最终将形成一个纳什稳定的联盟划分并能适应车辆的动态变化.仿真结果表明,模型的算法性能接近于最优联盟分配.     

网络虚拟化互通技术

工业界和学术界提出了许多新的网络虚拟化技术来满足云计算环境对网络服务的需求.网络虚拟化技术的多样化使得云环境面临多种网络虚拟化技术共存的状况.然而,网络虚拟化技术间的差异会导致网络资源被分割成相互间不可通信的“孤岛”.为了解决这个问题,提出了网络虚拟化互通技术,分析了该技术的实现难点,并提出了基于软件定义网络的网络虚拟化互通架构Omni-Bridge,最后给出了Omni-Bridge的原型实现和功能验证.     

换热型节能技术在基站中的应用研究

换热型节能技术虽在基站中得到了大量应用,但由于应用场景至今还没有科学客观定量评估规定,使工程实施处于一种无章可循的尴尬局面,阻碍了换热型节能技术的进一步推广和应用。深入研究分析了基站内各类设备工作环境温湿度、空气清洁度和换热型节能设备能效比等技术指标,对比了不同标准中相关技术指标,指出了不同标准相关技术指标差别和部分标准存在的问题,并结合大气空气质量和环境温度等因素,提出了换热型节能技术应用场景和新风系统工程设计方法。     

Energy efficiency optimization for HCNs based on small base station transmission power allocation

In the research of green communication, considering the base station (BS) power allocation from the perspective of energy efficiency (EE) is meaningful for heterogeneous cellular networks (HCNs) optimization. The EE of two-tier HCNs was analyzed and a new method for the network EE optimization was proposed by adjusting the small BS transmitting power. First, the HCNs ware modeled by homogeneous Poisson point processes (PPPs), and the coverage probability of BSs in each tier was derived. Second, according to the definition of EE, and the closed-form of EE was given by deriving the total power consumption and total throughput of HCNs respectively. At last, the analytical performance of the EE of HCNs on the small BS transmission power was analyzed, and a small BS power optimization algorithm was proposed to maximize the EE. Simulation results show that, the transmission power of small BS has a significant impact on the EE of HCNs. Furthermore, by optimizing the transmission power of small BS, the EE of HCNs can be improved effectively.     

加工误差对齿廓重迭干涉的影响

应用具体实例,研究了加工误差对少齿差内啮合齿廓重迭干涉的影响,并提出相应的解决方法。