基于Dijkstra算法的藏语分词研究

介绍了迪杰斯特拉(Dijkstra)算法的定义、思想和步骤。将一个藏语句子构成一个"线性"图,通过图中的算法实现藏语句子的分词操作。将典型图的非线性结构变成特殊的线性结构,并且通过辅助结点将图特殊化,最后再还原。实践证明,使用本方法能巧妙地使用Dijkstra算法来实现分词操作。     

PCC管控策略研究

对PCC的无线网及核心网的管控策略进行了研究和探讨。无线网部分提出了基于3项指标的小区PCC功能开启标准,核心网部分总结归纳了5种管控策略和实现流程,这些策略的实施可以有效管控数据业务,提升经营价值。     

数字卫星电视系统的相关测量

卫星信道的测试是广大卫星工作者的日常工作之一,正确理解所测参数的意义和测试原理,对于做好日常工作、提高工作水平是非常重要的.作者通过对各种测量参数的深入的理论分析,并结合多年的实践经验,阐述了数字卫星电视系统的相关测量原理,为卫星信道测试工作提供了理论依据.     

Reduced Graphene Oxides Modified Bi2Te3 Nanosheets for Rapid Photo-Thermoelectric Catalytic Therapy of Bacteria-Infected Wounds

Temperature variation-induced thermoelectric catalytic efficiency of thermoelectric material is simultaneously restricted by its electrical conductivity, Seebeck coefficient, and thermal conductivity. Herein, Bi₂Te₃ nanosheets are in situ grown on reduced graphene oxides (rGO) to generate an efficient photo-thermoelectric catalyst (rGO-Bi₂Te₃). This system exhibits phonon scattering effect and extra carrier transport channels induced by the formed heterointerface between rGO and Bi₂Te₃, which improves the power factor value and reduces thermal conductivity, thus enhancing the thermoelectric performance of 2.13 times than single Bi₂Te₃. The photo-thermoelectric catalysis of rGO-Bi₂Te₃ significantly improves the reactive oxygen species yields, resulting from the effective electron–hole separation caused by the unique thermoelectric field and heterointerfaces of rGO-Bi₂Te₃. Correspondingly, the electrospinning membranes containing rGO-Bi₂Te₃ nanosheets exhibit high antibacterial efficiency in vivo (99.35 ± 0.29%), accelerated tissue repair ability, and excellent biosafety. This study provides an insight into heterointerface design in photo-thermoelectric catalysis.     

New Polymerized Small Molecular Acceptors with Non-Aromatic π-Conjugated Linkers for Efficient All-Polymer Solar Cells

Developing new polymerized small molecular acceptor (PSMA) is pivotal for improving the performance of all-polymer solar cells. On the basis of this newly developed CH-series small molecule acceptors, two PSMAs are reported herein (namely PZC16 and PZC17, respectively). To reduce the molecular torsion caused by the traditional aromatic π-bridges, non-aromatic conjugated units (ethynyl for PZC16 and vinylene for PZC17) are adopted as the linkers and their effect on the photo-physical properties as well as the device performance are systematically investigated. Both polymer acceptors exhibit co-planar molecular conformation, along with broad absorption ranges and suitable energy levels. In comparison with the PM6:PZC16 film, the PM6:PZC17 film exhibits more uniform phase separation in morphology with a distinct bi-continuous network and better crystallinity. The PM6:PZC17-binary-based devices exhibit a satisfactory PCE of 16.33%, significantly higher than 9.22% of the PZC16-based devices. Impressively, PM6:PZC17-based large area device (ca. 1 cm²) achieves an excellent PCE of 15.14%, which is among the top performance for reported all-polymer solar cells (all-PSCs).     

射频隐身技术研究综述

机载用频设备的增加和截获接收技术的发展,导致航空器在电子对抗中的生存能力受到严重威胁。该文阐述了射频隐身的概念和基本原理,概括射频隐身技术的研究现状及主要矛盾。其次,重点以雷达射频辐射模型为主线,归纳了功率控制、波形设计、环境利用等时域、空域、频域、能量域的射频隐身技术,总结射频隐身领域的重要研究成果。最后,基于对已有算法和研究成果的分析,提出当前研究中存在的射频隐身技术局限性、评估指标单一性等问题,预测了射频隐身技术未来的研究方向。     

Design of 3.1–10.6 GHz ultra-wideband CMOS low noise amplifier with current reuse technique

A new low complexity ultra-wideband 3.1–10.6 GHz low noise amplifier (LNA), designed in a chartered 0.18 μm RFCMOS technology, is presented in this paper. The ultra-wideband LNA only consists of two simple amplifiers with an inter-stage inductor connected. The first stage utilizing a resistive current reuse and dual inductive degeneration techniques is used to attain a wideband input matching and low noise figure. A common source amplifier with inductive peaking technique as the second stage achieves high flat gain and wide the −3 dB bandwidth of the overall amplifier simultaneously. The implemented ultra-wideband LNA presents a maximum power gain of 15.6 dB, a high reverse isolation of −45 dB and a good input/output return losses are better than −10 dB in the frequency range of 3.1–10.6 GHz. An excellent noise figure (NF) of 2.8–4.7 dB was obtained in the required band with a power dissipation of 14.1 mW under a supply voltage of 1.5 V. An input-referred third-order intercept point (IIP3) is −7.1 dBm at 6 GHz. The chip area including testing pads is only 0.8 mm × 0.9 mm.     

终端靶场中相位畸变对近场光束质量的影响

终端靶场聚焦系统中的光学元件上存在不可避免的缺陷致使光场波前发生畸变,根据高功率激光装置终端靶场系统中强光束传输的特点,建立了描述光学元件引入的局域相位调制的模型,研究了终端靶场中具有高斯型相位波前畸变的平顶光束经过透镜会聚,并在后续防溅射板等熔石英介质中经历非线性增长的传输演变过程,详细分析了高斯型相位波前畸变、熔石英厚度和透镜焦距对终端靶场聚焦系统中的近场光束质量的影响。结果表明,高斯型波前畸变越严重、熔石英厚度越长、透镜焦距越短,近场光束质量越差,中高频增长越多。     

Frame-level bit allocation based on incremental PID algorithm and frame complexity estimation

Since the current rate control schemes in H.264 do not have the capability of efficient frame-level bit allocation, the video quality varies significantly from frame to frame especially for sequences with sudden scene changes or high motion activities. To overcome the limitation of frame-level bit allocation, we improve H.264 rate control scheme using two tools, the incremental proportional–integral–differential (PID) algorithm and the frame complexity estimation. The incremental PID algorithm is first introduced to control the buffer and reduce the influence of the buffer abrupt fluctuation in the process of frame-level bit allocation. To reduce more video quality variations, the frame target bit allocation is also adjusted by frame complexity that is estimated by residual energy. Simulation results show that the proposed rate control scheme, without introducing expensive computational complexity, decreases the average standard deviation of video quality by 32.29%.     

基于半分积分投影的车牌字符快速识别算法

提出了一种用于车牌识别的快速字符识别算法。首先利用半积分投影把大小为W×H的二值化字符图像转化为长度为2(W×H)的一维信号,保留了用于图像识别的关键特征,降低了后续算法的复杂度。然后将投影得到的数据进行离散Harr小波变换,抽取第二层小波变换后的低频系数并送入支持向量机进行训练识别。实验结果表明,所提算法可以使车牌字符的总识别率达到97.60%,平均识别时间为16.2ms,有效地提高了识别速度和精度。