10 research outputs found

    会计现状和未来发展前景分析

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    通常意义上,不同的人对会计的基本职能有不同的认知和观念。而会计作为一门热门的学科,很多大学生在选择自己的专业时候都会考虑会计这一专业作为自己的主修专业。本文笔者认为对于会计职能的不同观念在本质上是一致的,会计的发展现状与它本身的基本职能息息相关,也影响着会计专业未来发展的前景。基于此,笔者通过本文积极地探讨并围绕着会计现状和未来发展前景及其相关的问题展开了具体的分析与思考,极具现实意义

    Electrochemical Gating Single-Molecule Circuits with Parallel Paths

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    # These authors contributed equally to this work.电化学门控已成为一种可行且高效调节单分子电导的方法。在本研究中,我们证实了具有两个平行苯环的单分子电路中电子传输可以通过电化学门控控制。首先,我们利用STM-BJ技术以金为电极构筑了具有两条平行路径的单分子结。与单条路径的单分子结相比,两条路径的分子结由于具有增强性量子干涉效应,具有2.82倍的电导值。进一步地,我们利用电化学门控对具有两个平行苯环的单分结的电导进行调控,获得了333%·V-1调节比。结合DFT计算,发现在E=EF附近的V形透射系数谱图导致了实验观测的电导门控行为。本研究揭示了具有平行路径的单分子电路的电化学门控行为,并为设计高性能分子器件的分子材料提供了新的途径。通讯作者:周小顺E-mail:[email protected]:Xiao-ShunZhouE-mail:[email protected].浙江师范大学物理化学研究所,先进催化材料教育部重点实验室,浙江 金华 3210042.上海大学物理系,上海 2004441. Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, Zhejiang, China2. Department of Physics, Shanghai University, Shanghai 200444, Chin

    实用室内可见光通信连续干扰的消除

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    针对发光二极管之间的多径干扰,提出了采用QR分解的信道均衡算法消除干扰的方案。首先建立基于离散傅里叶变换扩频的正交频分复用技术的电力线与可见光融合通信系统,并考虑了由两个发光二极管之间的电线差所引发的多径干扰,然后比较了该系统下采用QR分解的信道均衡算法和传统信道均衡算法下的误码性能。结果表明,采用QR分解的信道均衡算法可消除由发光二极管之间的电线差引起的多径干扰,从而提高系统的传输性能

    基于小波变换的OFDM在电力线通信系统中的应用

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    研究了基于DWT(小波变换)的OFDM(正交频分复用)和FFT(快速傅里叶变换)的OFDM两种不同调制方式在PLC(电力线通信)系统中的性能。首先建立了两种不同调制方式下PLC的系统模型,然后在AWGN(加性高斯白噪声)和子CFO(载波频率偏移)的干扰下,分析了两种系统的误码性能以及峰均功率比的分布。通过仿真发现,在PLC系统中,DWT-OFDM系统比FFT-OFDM系统更具优势,在未来的PLC系统中必将发挥重要的作用

    基于OFDM和Nyquist单载波调制的可见光性能比较

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    针对可见光通信系统调制带宽有限的问题,提出了将两种具有高频带利用率的调制方式应用于可见光通信系统的方案。分别论述了正交频分复用和奈奎斯特单载波调制的基本原理和产生途径,仿真验证了正交频分复用和奈奎斯特单载波两种调制解调技术应用于可见光通信系统时的性能,比较分析了两种技术在不同信噪比条件下的误码率和频带利用率,仿真结果表明,奈奎斯特单载波相对于正交频分复用有更高的频带利用率和较低的误码率,更适用于可见光通信系统

    可见光通信定位集成系统仿真研究

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    为了提升可见光通信(VLC)定位系统的频谱和功率利用率,文章提出了一种基于非对称限幅和直流偏置的光正交频分复用(ADO-OFDM)的VLC定位集成系统。该通信定位集成系统具有比基于非对称限幅的光正交频分复用(ACO-OFDM)的VLC定位集成系统更高的频谱利用率和比基于加直流偏置的光正交频分复用(DCO-OFDM)的VLC定位集成系统更高的功率利用率。同时,文章还提出了一种差分修正定位算法,所提算法较于传统的三边定位算法其具有更高的定位精度

    Variations in the Upper Paleolithic adaptations of North China: A review of the evidence and implications for the onset of food production

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    JUNO Sensitivity on Proton Decay pνˉK+p\to \bar\nu K^+ Searches

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    The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in pνˉK+p\to \bar\nu K^+ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via pνˉK+p\to \bar\nu K^+ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is 9.6×10339.6 \times 10^{33} years, competitive with the current best limits on the proton lifetime in this channel

    JUNO sensitivity on proton decay pνK+p → νK^{+} searches

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    JUNO sensitivity on proton decay p → ν K + searches*

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    The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the pνˉK+ p\to \bar{\nu} K^+ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via pνˉK+ p\to \bar{\nu} K^+ is 36.9% ± 4.9% with a background level of 0.2±0.05(syst)±0.2\pm 0.05({\rm syst})\pm 0.2(stat) 0.2({\rm stat}) events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 9.6 \times 10^{33} years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies
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