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文章对两种双频率波段的光纤无线通信（Radio-Over-Fiber,ROF）系统模型进行了仿真分析。首先基于文献实验,实现了使用一个马赫-曾德调制器直接调制双频率波段的ROF系统模型,然后改为使用两个马赫-曾德调制器分别调制两个波段的系统模型。结果表明,在误码率BER=10-9,光纤长度为55 km的情况下,对于40 GHz频段,改进后的系统比改进前的系统性能提高5 dBm;从敏感度曲线上也可以看出,改进后的系统性能更稳定。

文章分析了一种利用外差检测所得微波信号的电场振幅和频率来计算后向布里渊散射光功率及频移的方法。该方法通过对功率较强的微波信号进行数值拟合,利用得到的直流分量和交流分量计算出后向散射光功率、频移及其随温度、应变变化的系数矩阵。数值结果表明,温度、应变的解调精度分别为1℃、100με,但也受到一定采样频率的限制。

在二维异步光码分多址（OCDMA）系统中,考虑光接收机存在多种噪声源干扰和用户之间存在的多址干扰（MAI）,使用了具有双硬限幅器（OHL）的光接收机来优化系统传输性能。文章数值分析了阈值、用户数和入射光功率等对系统误码率的影响。结果表明:双OHL二维异步OCDMA系统的误码率相对于单OHL系统和无OHL系统明显下降,基本消除了MAI。

文章从色散管理孤子（DMS）在光纤中传输满足的非线性薛定谔方程出发,推导出DMS系统中调制不稳定性（MI）增益谱的表达式,并给出了数值模拟结果。结果表明:色散管理图强度越强,对MI过程产生的增益的抑制作用越大;路径平均色散越大,抑制MI过程产生的增益越明显。

文章提出改进的并行干扰消除（PIC）技术来减少多址干扰对光码分多址（OCDMA）系统性能的影响。以光正交码（OOC）为地址码,推导出改进的PIC技术的系统误码率表达式。通过仿真分析给出了误码率与OOC的码长、码重和并发用户数的关系。结果表明,采用改进的PIC技术,能大大降低OCDMA系统的误码率,改善系统性能,且系统满足误码率≤10-9时所需的最小OOC码长远远小于PIC所需的最小OOC码长。

文章提出一种保证以太无源光网络（EPON）系统服务质量（QoS）的预估动态带宽分配（DBA）算法,该算法把多个子周期组合为一个超周期,在超周期中预估各级业务带宽,然后在子周期内参考预估值进行带宽分配;并对用户上行数据进行接入管理,维持QoS的稳定。实验结果表明,该算法既能保证各级业务的带宽利用率和时延要求,又能提供更加稳定的QoS。

文章研究了波分复用（WDM）光网络中动态业务下的波长分配问题,在无波长转换器的条件下,提出了一种加入了公平性考虑的动态门限算法。该算法在支持多优先级的动态门限法的基础上,通过更新初始优先级减少了不同距离光路连接请求间的阻塞率差别,改善了公平性。计算机仿真结果说明了该算法的有效性。

基于单硬限幅器（OHL）的同步光码分多址（OCDMA）系统不能完全消除信道串扰,引入了双OHL结构来优化系统传输性能。文章给出地址码的码重、光谱强度、用户数与误码率及同异步系统归一化吞吐量间的关系,结果表明:在用户数与地址码重相差较大的情况下,双OHL同步OCDMA系统误码率下降明显且比异步系统的归一化吞吐量大。

Copyright of Electromachining & Mould is the property of Electromachining & Mould Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

一、前言传输问题是通信系统的一个重要方面,而色散又是影响传输的重要因素,因此吸引了许多人进行研究,有关文章甚多。本文是为了搞清楚纤维对信号传输的影响,综合几篇文章写成,并对其中公式进行推导和提出看法。要确定光纤对信号的响应,可以把光纤当作四端网络,如图1所示。f（t）是输入信号的

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Clinical Healthcare is the property of Chinese Journal of Clinical Healthcare and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective In order to improve the adaptability of mobile robots to complex map environments, we propose a global path planning method called laser model, which improves the A* algorithm and ray model.Methods This method draws inspiration from the real-time scanning principle of planar light detection and ranging, which emits multiple virtual laser rays from the path node to the target point to perceive the boundary of obstacles, thereby quickly crossing obstacles and reaching the target point. At the same time, combined with the Floyd optimization algorithm, a safe, reliable, and stable global path is obtained in a relatively short time.Results In the concave environment of the experiment, the search time of the laser model is 99% faster than that of the A* algorithm and ray model, and the search process is reduced by 96%. In the experimental infeasible region, the laser model is 99% faster than the A* algorithm and ray model, and the search process is reduced by 97%. Compared with the double ant colony crossover algorithm, the laser model also performs better in concave environments.Conclusions The experimental results show that the proposed method is effective in solving the time consumption problems of concave traps and infeasible areas. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nanchang University (Engineering & Technology) is the property of Nanchang University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Functional Materials / Gongneng Cailiao is the property of Chongqing Functional Materials Periodical Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Modern Preventive Medicine is the property of Modern Preventive Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Chinese Journal of Cancer Biotherapy is the property of Editorial Office of Chinese Journal of Cancer Biotherapy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Cancer Biotherapy is the property of Editorial Office of Chinese Journal of Cancer Biotherapy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Chinese Journal of Aesthetic & Plastic Surgery is the property of Chinese Journal of Aesthetic & Plastic Surgery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Anhui Agricultural Sciences is the property of Journal of Anhui Agricultural Sciences Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biological culture is of great significance to the conservation of biodiversity. The formation and development of botanical gardens have reflected the plant culture which formed by human beings due to material and spiritual needs in history. Modern botanical gardens have made outstanding achievements in plant ex-situ protection, while the plant culture construction is still a little insufficient. In the process of global biodiversity conservation, the important roles of traditional culture in biodiversity conservation and sustainable use of biological resources have been increasingly valued. At this background, this study emphasized the close connection and co-evolution relationship between biocultural diversity and biodiversity, and reviewed the implication of plant culture in early botanical gardens and Chinese classical gardens. And through the analysis of the main functions of 3 085 modern botanical gardens around the world, we found that only 7.36% of botanical gardens carried out ethnobotanical research, while 11.18% carried out conservation biology research, and 17.18% worked out a plant conservation programme, which revealed the improvement of the protection function and the weakening of the cultural function of modern botanical gardens. Based on the demand for the construction of plant culture in the effective protection of plant diversity in the current botanical garden, this study further analyzed the deficiencies of plant culture construction in botanical gardens in China, including: (1) insufficient plant culture information data in plant species diversity information; (2) lack of consideration of benefit-sharing of traditional knowledge in biodiversity conservation; (3) lack of theme parks that display plant diversity with culture. Focused on the goal of plant diversity conservation and management in the China national botanical garden, we put forward the following suggestions on plant culture construction in the China national botanical garden system from three aspects, in order to provide a reference for the construction of a national botanical garden system with the characteristics of Chinese ecological civilization. Plant diversity protection and utilization: to strengthen the consideration of plant culture in the construction of plant diversity information and germplasm resource bank, encourage ethnobotanical research. Benefit-sharing: to establish access and benefit-sharing (ABS) standard procedures covering traditional knowledge to ensure fair and equitable benefit-sharing. Public participation: to consider display the regionality and uniqueness in China national botanical garden, and add ethnic plant culture theme parks or exhibition halls. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Computer-Aided Design & Computer Graphics / Jisuanji Fuzhu Sheji Yu Tuxingxue Xuebao is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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