46 research outputs found

    Design and Implementation of Passive Optical Network Management System for a Community Ethernet

    Get PDF
    随着通信技术的迅速发展,用户对带宽的需求越来越高。以成熟的以太网技术为基础的以太无源光网络(EPON)采用点到多点结构、无源光纤传输,能够在以太网之上提供多种业务。相对于传统的穿射设备以及技术而言,EPON其更加便于维护,承载业务更为灵活,因此是未来现代宽带入网的最佳选择之一。 虽然EPON设备都自带有网管系统,但是也存在着多种问题:首先,EPON网元管理系统只能分散管理自己的设备,不同厂商其设备存在较大差异性,从而造成了设备之间缺乏兼容性,没有办法实现各个设备之间的有效联结。其次,不同时期采用的网络体系结构、技术及通信监控网络差异很大,这就造成了对于设备的维护以及监督效能的降低,提升了设备...With the rapid development of communication technology, the user demand for bandwidth is more and more high. Ethernet passive optical network with Ethernet technology based (Ethernet Passive Optical Network, EPON) with point to multipoint architecture, passive optical transmission, can provide multiple services over Ethernet. It combines the advantages of passive optical network technology and Eth...学位:工程硕士院系专业:软件学院_工程硕士(软件工程)学号:X201323224

    非均匀温度场的可调谐激光吸收光谱诊断分析及其算法研究

    Get PDF
    高超声速燃烧问题中因为大量湍流及激波的存在,温度,组分的分布存在着极大的不均匀性。如何准确而可靠地诊断这些不均匀参数的分布对诊断超燃发动机燃烧工况具有重要意义。传统的热电偶测温技术由于热电偶的介入会对超声速流场产生重大干扰,且热电偶的电阻丝可能会被超声速燃烧下的高温流场烧毁或破坏,因此在超燃流场温度诊断时效果欠佳。而目前诊断超燃流场时使用最多的单通道吸收光谱技术由于检测的是激光路径上的平均值,其测量结果并不能有效反应流场中的不均匀性。本文中根据可调谐激光器的吸收光谱特性,尝试采用多组多波长激光器在二维平面组成激光网格,通过全局优化算法尝试求得全局不均匀温度场与浓度场的分布。和传统CT扫描实验方..

    Direct Fabrication of Ultrafine Electrospinning Nanofiber

    Get PDF
    采用装配有疏水铜网的新型喷头研究了超细纳米纤维的制备.静电纺丝实现之前,首先对铜网进行了疏水处理,并将其安装于喷头前端.静电纺丝过程中,聚合物溶液由精密注射泵输送至喷头处.安装于喷头的铜网可将管道内的聚合物溶液分成多股细流从铜网网孔中流出.从铜网网孔流出的溶液细流受电场力作用被拉伸成多股独立射流,并从喷头携带走聚集的正电荷.受铜网表面疏水性和射流间电荷排斥力的影响,从铜网喷射出的多股射流都将保持其独立的轨迹而不会产生聚集.疏水铜网有利于减小纺丝射流的初始直径,并获得均匀的超细纳米纤维.利用新型的电纺丝喷头成功制备了直径20~80 nM的聚氧化乙烯(PEO)和聚乙烯醇(PVA)超细纳米纤维.实验结果表明,超细纳米纤维的直径随着电纺丝溶液浓度的增加而变大.A novel spinneret assembled with Cu grid was presented in this paper to fabricate ultrafine nanofiber directly.Before electrospinning,hydrophobic treatment was performed on the Cu grid,which was then fixed at the front end of spinneret.During electrospinning,the polymer solution was transferred to the spinneret by the precise syringe pump.Through the holes in the Cu grid,polymer solution flow was divided into several smaller ones.The fine liquid flow from each hole of Cu grid was stretched into individual jets by the electric field force,and the liquid jets carried away the positive charges accumulated on the spinneret.Due to the hydrophobic treatment and the charge repulsive force between charged jets,liquid jets emanated from Cu grid kept their own tracks without aggregation.The initial diameter of liquid jet was greatly decreased by the Cu grid after hydrophobic treatment,and the smaller jet led to finer uniform nanofiber.Polyethylene oxide(PEO) and polyvinyl alcohol(PVA) ultrafine nanofiber with the diameter of 20—80 nm were fabricated by this novel spinneret,and the diameter of ultrafine nanofiber increases with the increase of polymer solution concentration.国家自然科学基金重点资助项目(51035002);国家自然科学基金资助项目(50875222

    Identification and analysis of odor of patients with exterior syndrome based on medical electronic nose

    Get PDF
    目的:运用自主研发的医用电子鼻探讨表证患者口腔呼气的气味图谱特征及气味识别准确率。方法:选择表证青年患者150例和健康青年人200名,运用基于薄膜型气体传感器阵列技术的医用电子鼻(nAnOfIlM-EnOSE MEdICAl001)采集口腔呼气的气味图谱,以响应曲线的振幅和上升斜率作为曲线特征,分析表证患者及其寒热病性的图谱特征,并进行判别分析。结果:表寒证和表热证患者的气味图谱响应曲线A、b、d、E、g、H的振幅和上升斜率均显著高于健康学生(P<0.01)。表热证患者的气味图谱响应曲线A、b、d、E、H的振幅和上升斜率均显著高于表寒证患者(P<0.05,P<0.01),表热证患者的气味图谱响应曲线g的振幅显著高于表寒证患者(P<0.01)。判别分析显示对健康青年人、表寒证青年患者、表热证青年患者口腔呼气的识别准确率分别为90.5%、86.5%、88.0%,对全部案例的识别准确率为89.1%。结论:表证青年患者口腔呼气的气味较健康青年人浓烈,且表热证青年患者气味变化较表寒证青年患者更明显,本医用电子鼻能够较为敏感和准确地辨识表证青年患者口腔呼气的气味特征及其寒热病性。医用电子鼻技术的发展可为中医嗅诊客观化研究提供手段和方法。Objective: to explore the odor response pattern characteristics of oral breath of patients with exterior syndrome and accuracy rates of odor identiication by medical electronic nose which was independent research and development.Methods: 150 young patients with exterior syndrome and 200 healthy young students were observed.Odor response patterns of oral breath were collected by the electronic nose(Nanoilm-Enose Medical001) based on a ilm of gas sensor array.The amplitude and rising slope of response curves were selected as curve characteristics to analyze pattern characteristics of exterior syndrome including exterior cold syndrome and exterior heat syndrome,and discriminant analysis was done.Results: In odor response patterns of patients with exterior cold syndrome and with exterior heat syndrome,the amplitudes and rising slopes of response curve A,B,D,E,G and H were signiicantly higher than those of healthy students(P<0.01).In odor response patterns of patients with exterior heat syndrome,the amplitudes and rising slopes of response curve A,B,D,E and H were signiicantly higher than those of patients with exterior cold syndrome(P<0.05,P<0.01),and the amplitude of response curve G was signiicantly higher than that of patients with exterior cold syndrome(P<0.01).Discriminant analysis showed that the accuracy rate of oral breath identiication of healthy students,patients with exterior cold syndrome and patients with exterior heat syndrome was 90.5%,86.5% and 88.0% respectively,and the accuracy rate of all cases was 89.1%.Conclusion: The odors of oral breath of patients with exterior syndrome were signiicantly stronger than those of healthy people.The odors of patients with exterior heat syndrome were signiicantly stronger than those of patients with exterior cold syndrome.This medical electronic nose could distinguish odor characteristic of oral breath of patients with exterior syndrome sensitively and accurately;and it could also distinguish odor characteristic of exterior cold syndrome from exterior heat syndrome.The development of medical electronic nose could provide a kind of new means for the study on the objectiication of TCM smelling examination.国家自然科学基金项目(No.30901899); 福建省教育厅A类项目(No.JA09132)~

    Room-temperature quantum interference in single perovskite quantum dot junctions

    Get PDF
    钙钛矿材料由于其高量子产率、载流子迁移率和独特的光致发光特性而在光电材料领域存在诸多潜在的重要应用。研究钙钛矿材料在纳米尺度下电荷输运的独特尺寸效应对钙钛矿光电器件的设计和开发具有重要的指导意义。洪文晶教授课题组基于机械可控裂结技术自主研发了具有皮米级位移调控灵敏度和飞安级电学测量精度的精密科学仪器,对南开大学李跃龙副教授团队合成的钙钛矿量子点进行了深入表征,研究工作成功将量子干涉的研究体系拓展至在光电领域具有重要应用的钙钛矿材料领域,为未来制备基于量子干涉效应的新型钙钛矿器件提供了一种全新的思路。 这一跨学科国际合作研究工作是在化学化工学院洪文晶教授、英国Lancaster 大学物理系Colin J. Lambert教授以及南开大学电子信息与光电工程学院李跃龙副教授的共同指导下完成的。化工系硕士研究生郑海宁、Lancaster University大学Songjun Hou博士、南开大学硕士研究生辛晨光为论文第一作者。博士后林禄春,博士研究生谭志冰、郑珏婷,硕士研究生蒋枫、张珑漪,本科生何文翔、李庆民等参与了论文的研究工作。刘俊扬特任副研究员、师佳副教授和萨本栋微纳米研究院杨扬副教授也参与了部分指导工作。The studies of quantum interference effects through bulk perovskite materials at the Ångstrom scale still remain as a major challenge. Herein, we provide the observation of roomtemperature quantum interference effects in metal halide perovskite quantum dots (QDs) using the mechanically controllable break junction technique. Single-QD conductance measurements reveal that there are multiple conductance peaks for the CH3NH3PbBr3 and CH3NH3PbBr2.15Cl0.85 QDs, whose displacement distributions match the lattice constant of QDs, suggesting that the gold electrodes slide through different lattice sites of the QD via Auhalogen coupling. We also observe a distinct conductance ‘jump’ at the end of the sliding process, which is further evidence that quantum interference effects dominate charge transport in these single-QD junctions. This conductance ‘jump’ is also confirmed by our theoretical calculations utilizing density functional theory combined with quantum transport theory. Our measurements and theory create a pathway to exploit quantum interference effects in quantum-controlled perovskite materials.This work was supported by the National Key R&D Program of China (2017YFA0204902, 2014DFE60170, 2018YFB1500105), the National Natural Science Foundation of China (Nos. 21673195, 21503179, 21490573, 61674084, 61874167), the Open Fund of the Key Laboratory of Optical Information Science & Technology (Nankai University) of China, the Fundamental Research Funds for the Central Universities of China (63181321, 63191414, 96173224), and the 111 Project (B16027), the Tianjin Natural Science Foundation (17JCYBJC41400), FET Open project 767187—QuIET, the EU project BAC-TO-FUEL and the UK EPSRC projects EP/N017188/1, EP/M014452/1. 该工作得到国家重点研发计划课题(2017YFA0204902)、国家自然科学基金(21673195、21503179、21490573)、厦门大学“人工智能分析引擎”双一流重大专项等项目的资助,也得到了固体表面物理化学国家重点实验室、能源材料化学协同创新中心的支持

    Retrieving the Most Prevalent Small Fullerene C(56)

    Get PDF
    通讯作者地址: Xie, SY (通讯作者),Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] of China,20721001 ,21031004 973 Program 2007CB815301 2011CB93590

    A study on the interfaces for coupling capillary eletrophoresis with flame photometric detector

    No full text
    讨论了毛细管电泳仪与火焰光度检测器的连接问题。介绍了两种将毛细管电泳流出液导入火焰光度检测器的方式。对两种接口各自的适用范围及其对火焰光度检测器的要求作了探讨。The problems with respecty to coupling capillary electrophoresis with flame photometic detector are investigated, Two types of interfaces for introducing capillary affluent into flame are described, Their range of applications and the requrements on the detectors are discussed国家自然科学基金!2947727

    Preparation, characteristics and applications of several grounding electrodes For capillary electrophoreis

    No full text
    介绍了几种毛细管电泳接地电极的制作方法,包括醋酸纤维膜接地电极接口,导电胶电极,液滴接触电极接口和焊锡电极。比较了这几种接地电极的性能和可能的用途。The procedures For preparing 4 kinds of grounding electrodes For capillary electrophoresis are introduced, including cellulose acetate-coated electrode, electric conductive glue electrode, electrolyte dropping electrode and tin soldered electrode.The characteristics and applications of those electrodes are compared.国家自然科学基金!2947727

    Hyphenated Technique of Capillary Electrophoresis and Flame Photometric Detection

    No full text
    研究了毛细管电泳与火焰光度检测器的联用技术及其应用。有机磷农药经毛细管电泳分离后,流出液被引入气相色谱的火焰光度检测器进行特效检测。毛细管电泳的接地电极接口采用毛细管裂缝处裹醋酸纤维膜的方法,而毛细管电泳和火焰光度检测器的接口则借用了气相色谱的进样口。本工作对各有关参数进行了研究、选择和讨论,揭示了火焰光度检测器做为毛细管电泳在线检测器的可能。A novel technique of hyphenation of capillary electrophoresis (CE) and flame pho- tometric detection (FPD) and its application are introduced.Organophosphorous Pesticides were separated by CE and on line detected with a FPD which was originally a detector of gas chromatography.Capillary fracture coated with cellulose acetate porous polymer was inter- faced to the ground electrode of CE.The interface of CE and FPD directly utilized the injec- tion pot of GC.The parameters were studied and optimized.The study shows the possibility of FPD as a new on line detector for CE.国家自然科学基金资助项目!(No.29477273
    corecore