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近些年，江西桃红岭梅花鹿国家级自然保护区植被正向演替明显，大量梅花鹿（Cervus nippon）开始向保护区外围扩散和聚集，调查桃红岭梅花鹿潜在病原携带情况，有利于掌握其种群健康状况，进而制定精确的保护管理对策，因此在该保护区不同区域（核心区、缓冲区和实验区）采集梅花鹿新鲜粪便样品，并基于宏基因组测序技术分析其病原携带情况。结果表明：桃红岭梅花鹿携带病原微生物包括细菌、真菌、放线菌、支原体、衣原体和螺旋体，共34属63种，其中包含大量人兽共患病病原；病原丰度最高的5个属分别是拟梭菌属（Clostridioides）、李斯特菌属（Listeria）、克雷伯氏菌属（Klebsiella）、志贺氏菌属（Shigella）和沙门氏菌属（Salmonella），丰度最高的 5个种分别是艰难拟梭菌（Clostridioides difficile）、单核增生李斯特氏菌（Listeria monocytogenes）、肺炎克雷伯氏菌（Klebsiella pneumoniae）、肠炎沙门氏菌（Salmonella enteritidis）和福氏志贺氏菌（Shigella flexneri）；不同研究区域中，核心区梅花鹿携带病原数量显著低于缓冲区和实验区。以上结果表明，桃红岭梅花鹿携带有多种病原，存在一定疫病发生风险。建议在保护区核心区积极开展栖息地矮化工作，同时开展高危病原的持续性监测及预警，并加强对保护区外围扩散梅花鹿种群的保护管理。

为探究同域分布的有蹄类动物活动节律及其季节性差异，2017年3月—2019年5月，利用红外相机技术在江西桃红岭梅花鹿国家级自然保护区对有蹄类动物开展野外监测。在15 208个相机有效工作日中，共拍摄到梅花鹿（Cervus nippon）、野猪（Sus scrofa）和小麂（Muntiacus reevesi） 3种有蹄类动物，相对丰富度依次为3.90%、9.72%和39.59%。年活动格局分析表明，梅花鹿和野猪在4月相对丰富度最高，小麂在5月和7月相对丰富度最高，三者均在12月相对丰富度最低。核密度估计和重叠系数的分析结果表明：（1）在日活动节律上，梅花鹿属于夜间活动为主、晨昏活动为辅类型，野猪与小麂同属于以晨昏活动为主、昼间活动为辅类型。（2）梅花鹿日活动节律存在明显的季节性变化，春季与夏季的重叠系数最高（Δ=0.83）。野猪与小麂日活动节律无明显的季节性变化。（3）不同物种日活动节律的重叠系数存在差异。野猪与小麂的日活动模式高度重叠，但与梅花鹿的活动高峰基本错开。研究揭示了3种有蹄类动物的活动节律及其季节性差异，为深入开展同域分布有蹄类物种的共存机制奠定了基础。

中东北非地区能源转型进展缓慢，加速部署太阳能、风能等可再生能源资源，推动电源、电网协同规划与项目开发融资模式创新是实现区域可持续发展的必经之路。区域电力市场缺乏顶层设计，电网消纳和调节能力不足，限制了中东北非可再生能源大规模开发利用。为此，详细梳理了中东北非电源开发以及电网互联发展现状，分析总结了中东北非电源、电网规划目标，明确了区域当前电力背景下的可持续发展路径。基于当前中东北非能源现状，探讨提出“清洁开发-规模储能-海水淡化-绿色制氢-电力出口联动发展模式”，为中资电力环保企业深耕“一带一路”沿线阿拉伯国家市场，以及中国牵头建设东北亚电力市场提供借鉴和参考。

将空分复用技术与DWDM（密集波分复用）技术相结合,在国内首次实现了560Tbit/s相干光双偏振DFT-s（离散傅里叶变换）OFDM（正交频分复用）32QAM（正交幅度调制）信号传输10km单模7芯光纤的演示实验。系统使用了16个独立光源产生375个25GHz栅格的DWDM信道,单芯传输容量为85.91Tbit/s,7芯传输总容量为601.36Tbit/s。系统使用普通FEC（前向纠错）编码,解码门限为3.8×10-3,编码冗余为7%,系统净传输速率为562.02Tbit/s,净谱效率为59.95bit/s/Hz。

文章介绍了基于31.786Gbaud/s光收发模块实现的32×100Gbit/s信号速率、2 080km标准单模光纤的实时相干光传输试验,信号采用PM-QPSK（偏振复用四相相移键控）调制格式。信号光源为单个激光器产生的32路波分复用子光载波,频率间隔为32GHz,频谱效率达到3.11bit/s/Hz。信号传输2 080km后,采用20%的FEC（前向纠错）编码时,Q值仍有1.2dB的余量。此外,还研究了光滤波器带宽与OSNR（光信噪比）代价的关系。25h挂机试验结果显示,信号接收纠错前误码率在1E-2以下,表明该传输系统稳定可靠。该系统为国内首个单光源3.2 Tbit/s实时传输试验系统,对提升现有100Gbit/s商用光纤传输系统的传输效率有较大的指导意义。

文章分析了以太网无源光网络（EPON）和波分复用无源光网络（WDM-PON）的多址技术、物理层关键技术和二层协议,特别针对这两种技术点对点仿真（P2PE）的实现给出了详细的分析,比较了这两种技术的性能,最后给出了结论并指出了二者不同的应用方向。

传统的16QAM（16进制正交幅度调制）相干光系统的相位估计算法主要采用QPSK（正交相移键控）分圈法,然而受放大器ASE（自发辐射）噪声的影响,星座点的径向移动将对相位恢复的准确度造成严重影响。文章针对星座点受噪声影响程度的不同,对QPSK分圈法中的分类幅值阈值进行详细分析,并引入不同权重。蒙特卡罗仿真结果表明,该改进方法不仅能有效提高16QAM的相位恢复精度,而且具有更低的误码率。

动态带宽分配是以太网无源光网络（EPON）系统的一个重要研究领域,文章提出一种在EPON系统中保证动态带宽分配公平性的新型算法。该算法计算量适中,同时兼顾了动态带宽分配的效率和公平性。文中通过推导给出了最优算法,并在模拟流量下进行了仿真,通过与已有算法的对比,证明其有很好的性能。

以太网无源光网络（EPON）已成为宽带接入的最有效通信方式之一,为其提供一个稳定、高效的软件系统尤为重要。文章简要介绍了EPON的系统结构及其软件系统的基本要求,并对提供传输控制协议/网际协议（TCP/IP）路由服务的开源路由包Quagga作了相应的介绍。Quagga能够满足EPON软件系统的要求并提供其所需的基本功能。文章论述了通过借鉴Quagga的构架来实现EPON的总体软件设计方案。

梅花鹿南方亚种被IUCN濒危物种红皮书列为濒危级,仅分布于安徽南部、江西东北部和浙江西北部,分布区域日益萎缩,分布区之间隔离程度较大。江西桃红岭是该亚种分布区之一,为保护该亚种,1981年成立桃红岭自然保护区,2001年升级为国家级自然保护区。为了解桃红岭野生梅花鹿现生种群数量,评估保护区过去30 a的保护成效,我们于2011年秋季采用直接计数的广义样线法开展梅花鹿种群调查。调查结果表明,保护区内梅花鹿数量为365只,密度为2.92只/km2,近年来梅花鹿种群增长较慢。经过30 a的保护,该保护区自然植被正在演替恢复。然而,当地的顶级植物群落可能并不是梅花鹿的适宜生境。因此,近年来,梅花鹿向保护区外扩散趋势明显,由此带来的各种管理问题值得关注。

本文介绍不锈钢PC型单模光纤活动连接器的设计及制造。它的插针体采用不锈钢材料,其端面加工成凸球面形。该连接器插入损耗典型值为0.3dB,回波损耗大于35dB,抗反射性能强,特别适用于大容量、超高速数字传输、宽频带图象模拟传输及本地网（LAN）等光纤通信系统。

本文介绍一种结构新颖、能重复使用、接续快的光纤固定连接器（FMS-1型）。该器件仅由两只元件构成,体积小。对单模光纤的平均插入损耗为0.173dB,对多模光纤的插入损耗

本文介绍一种两信道波分复用/解复用器的设计和特性参数。复用器结构简单可靠,插入损耗小于1.0dB,串扰在-22dB以下。

本文分析了光纤无源器件中使用的自聚焦透镜产生耦合损耗的原因,并提出了解决办法。文中还介绍了采用光学对中法将光纤与自聚焦透镜耦合成自聚焦透镜光纤软线的制作过程及其应用。

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The deformation of the Yangtze River embankment on soft and water-rich strata is greatly affected by the disturbance of the construction of the shallow buried super-large diameter shield tunnel. Based on on-site monitoring data, under the background of a large double-line shield tunneling project with a diameter of 15. 07 m, the spatiotemporal evolution law of the settlement of the Wuwei Yangtze River embankment was studied and the rationality of excavation parameters and embankment reinforcement measures were analyzed. The research results indicate that the amplitude of surface settlement of embankments can be effectively reduced by the reinforcement treatment of compacted grouting. When the right tunneling passed through the embankment, the overall settlement deformation of the embankment above the central axis increased with the number of days the shield tail leaves. The maximum settlement was located in the front section of the embankment, which was 20. 37mm, and there was generally a slight uplift far from the central axis. After the left tunneling passed through the embankment, the overall vertical deformation of the embankment followed a distribution pattern of “ uplift of the front and back sections of the left embankment, settlement of the embankment section, and overall settlement of the right line, with a decrease in amplitude from the front section to the back section of embankment” . Thus, it is concluded that when shield tunneling passes through the Yangtze River embankment, the adjustment of excavation parameters such as incision pressure, thrust, and torque is affected by the overload effect of the embankment. [ABSTRACT FROM AUTHOR]

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As the beginning of the digestive tract, the mouth has a natural connection with the intestines and the liver. Oral diseases are also closely related to liver diseases. Periodontitis is the most common oral disease and its periodontal bacterial lesions often influence the prognosis and progression of liver disease through direct anatomical invasion and the oral-gut-liver axis. Periodontal bacteria can also affect the liver through damaged intestinal epithelium circulating through the portal vein. This article provided a systematic review of periodontitis, the oral-intestinal-hepatic axis, and liver disease. [ABSTRACT FROM AUTHOR]

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