对以太网无源光网络中OAM的分析

以太网无源光网络(EPON)作为一种新兴的接入技术,需要网络设计者提供电信级(Carrier-class)的管理能力,而单纯的简单网络管理协议(SNMP)已经不能胜任其运营、管理、维护(OAM)的要求.文章提出了基于802.3ahOAM协议和SNMP的EPON系统管理机制,并描述TEPON系统OAM的功能、特点以及在Linux操作系统下该刚络管理机制的软件实现方案.     

A 20.8-Gbps Dual-Carrier Wireless Communication Link in 220-GHz Band

With the successful demonstration of terahertz (THz) high-speed wireless data transmission,the THz frequencies are now becoming a worth candidate for post-5G wi...     

新型波导-微带对脊鳍线过渡设计

介绍了一种新型的宽带波导-微带对脊鳍线过渡设计。它利用对脊鳍线自身结构的调整,就可以对频带内谐振频率产生抑制作用,不需外加任何谐振抑制结构或金属孤岛,减少了设计和制造的复杂性。这种紧凑的过渡模型不仅结构简单、尺寸短小,而且可以在宽频带范围内实现较低的插入损耗和回波损耗,方便工程上的应用。对实验样品的测试表明,在Ka全频段内其插入损耗小于0.8 dB。     

Measurements and Characterization for the Vehicle-to-Infrastructure Channel in Urban and Highway Scenarios at 5.92GHz

In the future smart transportation system, reliable vehicle-to-infrastructure(V2 I) communication is very important to ensure vehicle driving safety and to improve vehicle driving efficiency. In this paper, V2 I channel measurements at 5.92 GHz are conducted in typical urban and highway scenarios.The frequency and bandwidth of transmission, as well as the deployment of the RSU(roadside unit) and the OBU(on board unit), are selected by considering the recommendation proposed by 3 GPP TR 36.885. T...     

Fe2O3气敏材料研究进展

综述了近年来Fe_2O_3气敏材料常用的合成方法,如sol-gel法,沉淀法,水热法和微乳液法。总结了焙烧温度与掺杂效应对气敏性能的影响,探讨了气敏机理模型,并对今后的研究方向提出了一些看法。     

Flavonoids from Lycium barbarum Leaves Exhibit Anti-Aging Effects through the Redox-Modulation

Lycium barbarum leaves are a kind of vegetable, and modern nutrition studies have found that they have an anti-aging function. Our study aims to investigate the anti-aging effects of Lycium barbarum leaf flavonoid (LBLF) extracts and its underlying molecular mechanism. LBLFs were purified using D101 and polyamide resin, characterized by ultraperformance liquid chromatography coupled with mass spectrometry, and administered to hydrogen peroxide (H₂O₂)-treated human umbilical vein endothelial cells (HUVECs) and Caenorhabditis elegans. Appropriate enrichment conditions were optimized through dynamic adsorption and desorption experiments, the content of flavonoids reached 909.84 mg/g, rutin and kaempferol being the main ones. LBLFs attenuated H₂O₂-induced HUVEC apoptosis, decreased reactive oxygen species and malondialdehyde production levels, increased superoxide dismutase, glutathione peroxidase and catalase activities. Furthermore, pre-treatment with LBLF increased mRNA expression of erythropoietin (EPO) and heme oxygenase-1 (HO-1) via the mitogen-activated protein kinase (MAPK) signaling pathway in HUVECs. Compared with 100 µM rutin monomer, LBLF prolonged the lifespan of Caenorhabditis elegans, enhanced their mobility in middle life stages and upregulated expression of sod-2, gcs-1 and skn-1 genes, which indicated that the anti-aging effects of LBLF were due to its redox-modulation.     

一种高性能太阳敏感器复合光学系统设计

以夫朗禾费衍射理论为基础,结合微透镜,设计了一种高性能的数字式太阳敏感器复合光学系统。分析了光学系统的组成,建立了光学系统的数学模型,设计了光学系统的焦距、孔径和微透镜参量,并进行了成像的数值仿真。仿真结果表明,与基于掩模的光学系统相比,这种新型的复合光学系统成像光斑能量分布集中,保证计算光斑中心位置的高精度,使敏感器具有大视场和高精度的特点。     

大行程位移台干涉测距系统的误差补偿

双频激光干涉仪作为常用的精密光学非接触式测量设备,具有精度高、抗干扰能力强、灵活性好等优点。然而环境温度变化、机械振动等因素可能会影响其测量结果的准确性,并且影响程度会随着测量光程的增加而增大。针对基于双频激光干涉仪的大行程位移台测距系统,首先研究了位移台测距系统的测量原理,然后针对系统存在的各项误差进行了分析和补偿,最后,对系统进行综合误差补偿实验,短时间补偿量达到10^-8 m量级,且时间越长补偿效果越好。该方法较现有的误差补偿方法更为完整,补偿量更大。     

基于DFB激光器的振动传感系统改进PGC解调算法

相位生成载波(Phase Generated Carrier, PGC)解调算法是目前光纤干涉传感领域中重要的解调算法。针对目前PGC解调算法中光强扰动和调制深度影响信号解调准确度的问题,提出了一种改进的PGC解调算法(PGC-Ameliorated),并搭建了基于分布反馈(Distributed Feedback, DFB)激光器的振动传感系统进行实验验证。实验结果表明,当被测振动信号的频率为800 Hz时,该算法信噪比为57 dB,优于微分交叉相乘(Differential and Cross Multiplying, DCM)算法和反正切(Arctan)算法近20 dB。在不同光强下,该算法解调信号幅值波动范围在±0.02 rad;在不同调制深度下,该算法总谐波失真最小为0.61%,信纳比最大为25.9 dB,相比于DCM算法和Arctan算法具有更低的总谐波失真和更高的信纳比。     

线性移位寄存器在安全RSA模数中应用的研究

运用线性移位寄存器(LFSR)序列模2个不同素数时的周期一般不同这一性质,尝试构造分解另一类RSA模数的方法;指出对于RSA模数n=pq的一个素因子P,当P2+p+1,P3+P2+p+1,…其中之一仅含有小的素因子时,给出的算法能够分解合数n=pq,并给出了一个基于三级LFSR分解合数的实例来说明算法的具体运算步骤.根据该分解算法,在选取RSA模数时,为确保安全性,除避免已知的不安全因素以外,还需要保证n的素因子P满足P2+P+1,P3+P2+P+1,…均包含大的素因子.