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Effects of warming and clipping on plant and soil properties of an alpine meadow in the Qinghai-Tibetan Plateau, China

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Journal of Arid Land 2015年第2期7卷 189-204页

作者： man Hou XU Fei PENg Quan ga.g.YOU Jian gUO Xia Fei TIAN Min LIU Xian XUE Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Taiyuan Normal University

Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau （QTP） in China. However, it is lacking of studies on the effects of warming and grazing on plant and soil properties in these alpine ecosystems. In this study, we reported the related research from manipulative experiment in 2010-2012 in the QTP. The aim of this study was to investigate the individual and combined effects of warming and clipping on plant and soil properties in the alpine meadow ecosystem. Infrared radiators were used to simulate climate warming starting in July 2010, while clipping was performed once in Octo- ber 2011 to simulate the local livestock grazing. The experiment was designed as a randomized block consisting of five replications and four treatments： control （CK）, warming （W）, clipping （C） and warming＋clipping combination （WC）. The plant and soil properties were investigated in the growing season of the alpine meadow in 2012. The results showed that W and WC treatments significantly decreased relative humidity at 20-cm height above ground as well as significantly increases air temperature at the same height, surface temperature, and soil temperature at the depth of 0-30 cm. However, the C treatment did not significantly decrease soil moisture and soil temperature at the depth of 0-60 cm. Relative to CK, vegetation height and species number increased significantly in W and WC treatment, respectively, while vegetation aboveground biomass decreased significantly in C treatment in the early growing season. However, vegetation cover, species diversity, belowground biomass and soil properties at the depth of 0-30 cm did not differ significantly in W, C and WC treatments. Soil moisture increased at the depth of 40-100 cm in W and WC treatments, while belowground biomass, soil activated carbon, organic carbon and total nitrogen increased in the 30-50 cm soil layer in W, C and WC treatments. Although the initial res

关键词： simulated warming overgrazing soil property plant property alpine meadow ecosystem Qinghai-Tibetan Plateau

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对称的扩展二元相移键控调制解调方法研究

电波科学学报 2016年第6期31卷 1138-1144页

作者：彭珊冯熳东南大学信息科学与工程学院南京210018

为了提高扩展二元相移键控(Extended Binary Phase Shift Keying,EBPSK)系统的抗衰落性能,并简化解调器结构,提出了一种对称的扩展二元相移键控(Symmetric-EBPSK,S-EBPSK)调制方式,以"0"、"1"码元对称的调制波形为主要特征,采用简单有... 详细信息

为了提高扩展二元相移键控(Extended Binary Phase Shift Keying,EBPSK)系统的抗衰落性能,并简化解调器结构,提出了一种对称的扩展二元相移键控(Symmetric-EBPSK,S-EBPSK)调制方式,以"0"、"1"码元对称的调制波形为主要特征,采用简单有效的冲击滤波加比较判决的方法来完成解调,并从理论上推导了S-EBPSK系统的功率谱,及加性高斯白噪声(Additional White gaussian Noise,a.g.)信道下系统的理论误码率公式.仿真结果表明了所提方案实现简单有效,且无论在a.g.信道还是衰落信道下,均表现出了明显的性能优势.

关键词：对称的扩展二元相移键控调制冲击滤波器比较判决加性高斯白噪声平坦瑞利衰落

Fe_3O_4@SiO_2@TiO_2复合纳米结构的尺寸与磁性调控

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原子与分子物理学报 2016年第5期33卷 886-892页

作者：李蔓红王芳山西师范大学化学与材料科学学院磁性分子与磁信息材料教育部重点实验室临汾041004

采用共沉淀法和溶剂热法制备了不同尺寸的Fe_3O_4纳米粒子,通过Stber法和溶胶-凝胶法在Fe_3O_4磁核上包覆SiO_2和Ti O2壳层获得不同尺寸的Fe_3O_4@SiO_2@Ti O2复合纳米结构.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微... 详细信息

采用共沉淀法和溶剂热法制备了不同尺寸的Fe_3O_4纳米粒子,通过Stber法和溶胶-凝胶法在Fe_3O_4磁核上包覆SiO_2和Ti O2壳层获得不同尺寸的Fe_3O_4@SiO_2@Ti O2复合纳米结构.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和振动样品磁强计(VSM)等对其结构、形貌和磁性进行了研究.结果表明,大尺寸复合纳米粒子包覆均匀,分散性好,饱和磁化强度较大,有利于TiO_2光催化剂的磁回收与再利用.

关键词： Fe3O4纳米粒子 Fe3O4@SiO2@TiO2 复合纳米结构磁回收

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随机极性MCP-EBPSK传输性能

东南大学学报（自然科学版） 2012年第6期42卷 1031-1035页

作者：靳一吴乐南冯熳邓蕾东南大学信息科学与工程学院南京210096

为提高随机极性的修正连续相位扩展二元相移键控(MCP-EBPSK)调制信号的传输性能,对比了a.g.信道上自适应门限判决、BP神经网络和支持向量机(SVM)判决3种解调方式的解调性能,并引入了RS码和规则LDPC码来进行改善.根据随机极性MCP-EBPSK... 详细信息

为提高随机极性的修正连续相位扩展二元相移键控(MCP-EBPSK)调制信号的传输性能,对比了a.g.信道上自适应门限判决、BP神经网络和支持向量机(SVM)判决3种解调方式的解调性能,并引入了RS码和规则LDPC码来进行改善.根据随机极性MCP-EBPSK调制原理和数字冲击滤波器特殊滤波机理,设计了基于自适应门限判决、BP神经网络和SVM的解调器.同时,在这3种解调方式性能均不佳时,对RS码和规则LDPC编码的随机极性MCP-EBPSK传输性能进行了仿真.仿真结果表明:在a.g.信道上,自适应门限判决、BP神经网络和SVM三种解调方式的解调性能相差不大;当采用自适应门限判决且误码率为10-4时,RS码和规则LDPC码的编码增益分别约为4 dB和7 dB.因此,引入信道编码可显著改善随机极性MCP-EBPSK的传输性能.

关键词：修正连续相位扩展二元相移键控自适应门限判决 BP神经网络支持向量机数字冲击滤波器编码增益

Analysis and optimization of power spectrum on EBPSK modulation in throughput-efficient wireless system

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Journal of Southeast University(English Edition) 2008年第2期24卷 143-148页

作者：冯熳戚晨浩吴乐南东南大学信息科学与工程学院南京210096

In order to satisfy increasingly greater demand for the performance of communication systems, a throughput efficient wireless system based on the extended binary phase shift keying （EBPSK） modulation is presented. Simultaneously, corresponding analysis of power spectra is also given with a brief process. The optimal waveform is proposed without useful information loss, by removing linear spectra presenting periodic components. On this basis, the reasonable definition of bandwidth is discussed, which indicates that the EBPSK belongs to the category of the ultra narrow band （UNB） throughput-efficient communication. Meanwhile, the modulation parameters＇ effects on bandwidth, transmission rate and transmission performance are analyzed. Results illustrate the validity of theoretical analysis and spectrum optimization. Results also prove that this UNB system can obtain good bit error rate （ber） performance with high spectra efficiency.

关键词： extended binary phase shift keying power spectrum ultra narrow band spectra efficiency

A Novel Semiconductor CIgS Photovoltaic Material and Thin-Film ED Technology

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Journal of Semiconductors 2001年第11期22卷 1357-1363页

作者： ZHENg gua.g.fu 1,Ya.g.Hong xing 1,man Cheuk ho 1,WONg Wing lok 2, AN Da wei 1 and John BURNETT 1(1 Centre for Development of Solar Energy Technology,Department of Building Services Engineering, The Hong Kong Polytechnic University,Hong Kong,C 香港工业大学香港 Hong Kong Solar Tech Centre Mosum Investment Ltd 香港

In order to achieve low cost high efficiency thin film solar cells,a novel Semiconductor Photovoltaic (PV) active material CuIn 1-x ga x Se 2 (CIgS) and thin film Electro Deposition (ED) technology is ***,the PV materials and technologies is investigated,then the detailed experimental processes of CIgS/Mo/glass structure by using the novel ED technology and the results are *** results shows that high quality CIgS polycrystalline thin films can be obtained by the ED method,in which the polycrystalline CIgS is definitely identified by the (112),(204,220) characteristic peaks of the tetragonal structure,the continuous CIgS thin film layers with particle average size of about 2μm of length and around 1 6μm of *** thickness and solar grade quality of CIgS thin films can be produced with good *** and analysis on the ED technique,CIgS energy band and sodium (Na) impurity properties,were also *** alloy CIgS exhibits not only increasing band gap with increasing x ,but also a cha.g. in material properties that is relevant to the device *** beneficial impurity Na originating from the low cost soda lime glass substrate becomes one prerequisite for high quality CIgS *** novel material and technology are very useful for low cost high efficiency thin film solar cells and other devices.

关键词：半导体光电材料薄膜 ED技术

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一种新颖的宽带地空通信系统方案

西安电子科技大学学报 2008年第3期35卷 403-408页

作者：费满锋王杰令易克初刘祖军西安电子科技大学综合业务网理论及关键技术国家重点实验室

低仰角下的宽带地空通信信道存在严重的多径衰落现象，其信道特性与地面移动通信的情况很不相同，不适于采用正交频分复用技术，为此建立了低仰角下的宽带地空信道模型，并提出了一种正交码分复用与分组编码技术相结合的通信系统方案．... 详细信息

低仰角下的宽带地空通信信道存在严重的多径衰落现象，其信道特性与地面移动通信的情况很不相同，不适于采用正交频分复用技术，为此建立了低仰角下的宽带地空信道模型，并提出了一种正交码分复用与分组编码技术相结合的通信系统方案．理论分析和仿真实验结果表明：该系统能够容忍40个码元以内的多径时延，当信道的莱斯因子在6～7dB时仍然可以获得很好的误码特性．由于该系统采用多值PN码M元扩频实现正交码分复用，因此其频带效率与非扩频系统相同；其次其码元较短，因而对信道动态变化的适应能力优于相应的正交频分复用系统．此外，它不必进行信道估计和均衡，因而其硬件实现的复杂度很低，在宽带地空通信中具有很好的应用前景．

关键词：地空通信正交码分复用分组编码多径衰落

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试析用微信拓展高校图书馆服务的有力措施

玉林师范学院学报 2018年第6期39卷 144-146页

作者：唐冬曼玉林师范学院图书馆广西玉林537000

随着科学技术及信息技术的不断发展进步,微信成为移动设备上重要的交流平台之一。近年来,图书馆的信息化水平不断提升,大部分图书馆已经建立了微信公众号,为读者提供了更加便捷、全面的服务。但微信在图书馆服务功能拓展中的重要作用不... 详细信息

随着科学技术及信息技术的不断发展进步,微信成为移动设备上重要的交流平台之一。近年来,图书馆的信息化水平不断提升,大部分图书馆已经建立了微信公众号,为读者提供了更加便捷、全面的服务。但微信在图书馆服务功能拓展中的重要作用不仅仅是通过公众号提供快速便捷的借还服务以及关键消息的推送,微信的社群功能也具有较大的服务潜力,有待挖掘。本文分析了把微信社群等更多功能引入高校图书馆服务体系中的必要性及可行性,提出了应用微信的多重功能对高校图书馆服务功能进行拓展的建议。

关键词：高校图书馆服务水平微信措施

Performance analysis of PA coded pulse-position modulation for Space Optical Communications

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Performance analysis of PA coded pulse-position modulation f...