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基于电磁散射点间距的风电机雷达回波仿真

高电压技术 2019年第8期45卷 2652-2661页

作者：唐波郝斌张建功黄力干喆渊杨嘉炜三峡大学电气与新能源学院宜昌443002 中国电力科学研究院有限公司武汉430074

准确获取风电机雷达回波从而实现其独特性多普勒特征的提取,对解决风电场对雷达台站的无源干扰问题有重要意义。现有风电机回波积分算法忽视了散射点间距离散性,无法获取准确的风电机多普勒特征。为此,引入散射点间距参量,从雷达回波的... 详细信息

准确获取风电机雷达回波从而实现其独特性多普勒特征的提取,对解决风电场对雷达台站的无源干扰问题有重要意义。现有风电机回波积分算法忽视了散射点间距离散性,无法获取准确的风电机多普勒特征。为此,引入散射点间距参量,从雷达回波的基本方程出发,通过数学推演,获取了散射点间距对风电机回波影响的数学表征公式,从而提出了考虑散射点间距的风电机回波散射点算法。通过散射点间距不同取值范围的风电机回波时域分析,揭示了散射点间距对风电机回波多普勒特征的影响规律,实现了多普勒复杂特征的理论性解释。仿真结果表明,积分算法无法用于风电机回波保真性仿真,而合适取值下的散射点算法可以表征出风电机回波的复杂多普勒特征。

关键词：风电机散射点模型散射点间距积分算法散射点算法多普勒特征

特高压输电线路对邻近对空情报雷达站影响分析与实验研究

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高电压技术 2018年第10期44卷 3299-3306页

作者：刘兴发干喆渊李妮张建功张业茂电网环境保护国家重点实验室(中国电力科学研究院有限公司)

为了防护特高压输电线路对邻近对空情报雷达站的电磁干扰,分析了雷达阵地对特高压线路的距离要求,提出了特高压线路对雷达波的遮蔽损耗估算模型,在锡盟—山东特高压工程实测了线路带电和不带电时的无线电噪声,并在线路一侧距离线路1 66... 详细信息

为了防护特高压输电线路对邻近对空情报雷达站的电磁干扰,分析了雷达阵地对特高压线路的距离要求,提出了特高压线路对雷达波的遮蔽损耗估算模型,在锡盟—山东特高压工程实测了线路带电和不带电时的无线电噪声,并在线路一侧距离线路1 660 m处布置发射天线,线路另一侧20～350 m高度采用多旋翼无人机机载天线和频谱仪接收信号,频率范围80～3 200 MHz,实测线路对电磁波的遮蔽损耗。结果表明：交流特高压线路在80～1 000MHz的无线电噪声与背景值相当,线路带电前后没有明显一致性差异,不会干扰雷达信号接收;特高压线路对电磁波的遮蔽损耗在–5.2～2dB之间,最低导线下方区域损耗为–5.2～2dB,导线遮蔽区域损耗为–2.2～1.8dB,在P波段和经验公式估算接近,最高导线以上区域损耗迅速减小至背景波动,随着频率的增加,遮蔽损耗减小。应根据雷达类型确定特高压线路与雷达站的防护间距,米波雷达由阵地要求和遮蔽角确定防护间距。L和S波段雷达根据天线的仰角保证电磁波不遮蔽来确定防护间距;可通过降低线路高度、提高雷达天线、利用有高程差的有利地形来降低特高压线路对雷达的电磁影响。

关键词：特高压输电线路对空情报雷达站电磁干扰防护电磁波遮蔽损耗防护间距

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金属盖板对高压直流合成场测量的影响

高电压技术 2019年第2期45卷 651-657页

作者：王延召干喆渊周兵倪园黄锐张业茂中国电力科学研究院有限公司武汉分院电网环境保护国家重点实验室武汉430074

为了改善基于场磨的合成场测量系统在直流输电工程电磁环境监测应用中的便携性,对不加金属盖板的场磨测量技术进行研究。建立场磨及平行极板标定系统的三维仿真模型,仿真分析金属盖板面积、平行极板尺寸与间隙距离以及场磨结构参数对被... 详细信息

为了改善基于场磨的合成场测量系统在直流输电工程电磁环境监测应用中的便携性,对不加金属盖板的场磨测量技术进行研究。建立场磨及平行极板标定系统的三维仿真模型,仿真分析金属盖板面积、平行极板尺寸与间隙距离以及场磨结构参数对被测电场的影响。仿真结果表明:平行极板的间隙距离和极板大小对被测电场影响较小,而盖板的面积大小和场磨结构对被测电场影响较大。当盖板面积和场磨结构参数确定后,对被测电场的影响存在一个相对固定的电场畸变系数,该系数可以用于场磨的标定。采用平行极板对加盖板和不加盖板情况下的电场畸变情况进行试验研究,试验结果与仿真结果比较吻合,均表明不加金属盖板进行高压直流合成场测量是可行的。基于仿真和试验结果,提出两种不同的标定方法,并对不加金属盖板的场磨样机进行标定,现场试验结果表明标定之后的不加金属盖板的场磨可以满足工程上直流合成场强的测量需要。

关键词：直流输电场磨合成电场畸变系数标定

A Sustainable Dual Cross‑Linked Cellulose Hydrogel Electrolyte for High‑Performance Zinc‑Metal Batteries

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Nano-Micro Letters 2024年第6期16卷 63-75页

作者： Haodong Zhang Xiaotang gan Yuyang Yan Jinping Zhou Hubei Engineering Center of Natural Polymers‑Based Medical Materials Key Laboratory of Biomedical Polymers of Ministry of EducationCollege of Chemistry and Molecular SciencesWuhan UniversityWuhan 430072People’s Republic of China Zhongnan Hospital of Wuhan University Institute of Hepatobiliary Diseases of Wuhan UniversityTransplant Center of Wuhan UniversityWuhan 430072People’s Republic of China

Aqueous rechargeable Zn-metal batteries(ARZBs)are considered one of the most promising candidates for grid-scale energy ***,their widespread commercial application is largely plagued by three major challenges:The uncontrollable Zn dendrites,notorious parasitic side reactions,and sluggish Zn^(2+) ion *** address these issues,we design a sustainable dual crosslinked cellulose hydrogel electrolyte,which has excellent mechanical strength to inhibit dendrite formation,high Zn^(2+) ions binding capacity to suppress side reaction,and abundant porous structure to facilitate Zn^(2+) ions ***,the Zn||Zn cell with the hydrogel electrolyte can cycle stably for more than 400 h under a high current density of 10 mA cm^(−2).Moreover,the hydrogel electrolyte also enables the Zn||polyaniline cell to achieve high-rate and long-term cycling performance(>2000 cycles at 2000 mA g^(−1)).Remarkably,the hydrogel electrolyte is easily accessible and biodegradable,making the ARZBs attractive in terms of scalability and sustainability.

关键词： Cellulose Dual cross-linked Aqueous rechargeable Zn-metal batteries Hydrogel electrolyte

N-Heterocyclic carbene-catalyzed enantioselective(dynamic) kinetic resolutions and desymmetrizations

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Science China Chemistry 2024年第2期67卷 482-511页

作者： Yi Zhang Hui Cai Xiuhai gan Zhichao Jin National Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationGuizhou UniversityHuaxi DistrictGuiyang550025China

N-heterocyclic carbene-catalyzed enantioselective kinetic resolutions,dynamic kinetic resolutions,and desymmetrization reactions are systematically *** content is organized according to the activation modes involved i... 详细信息

关键词： N-heterocyclic carbene kinetic resolution dynamic kinetic resolution desymmetrization organocatalysis

Blast waveform tailoring using controlled venting in blast simulators and shock tubes

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Defence Technology（防务技术） 2024年第7期37卷 14-26页

作者： Edward Chern Jinn gan Alex Remennikov David Ritzel Faculty of Engineering and Information Sciences University of WollongongWollongongNSW2522Australia Dyn-FX Consulting Ltd 19 Laird Ave NorthAmherstburgONN9V 2T5Canada

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive *** tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance *** wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications,inadvertently cause flow anomalies,and/or are only applicable under very specific *** paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube *** use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator(shock tube)at the Australian National Facility of Physical Blast Simulation and via numerical flow simulations with Computational Fluid *** venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast *** control method also allows for the adjustment of parameters such as tuning the peak overpressure,the positive phase duration,and modifying the magnitude of the negative phase and the secondary shock of the blast *** paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied.

关键词： Advanced blast simulator Shock wave propagation Far-field explosion Blast loads Blast waves Computational fluid dynamics

WEAK APPROXIMATIONS OF STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS WITH FRACTIONAL NOISE

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Journal of Computational Mathematics 2024年第3期42卷 735-754页

作者： Meng Cai Siqing gan Xiaojie Wang School of Mathematics and Statistics HNP-LAMACentral South UniversityChangshaChina

This paper aims to analyze the weak approximation error of a fully discrete scheme for a class of semi-linear parabolic stochastic partial differential equations(SPDEs)driven by additive fractional Brownian motions with the Hurst parameter H∈(1/2,1).The spatial approximation is performed by a spectral Galerkin method and the temporal discretization by an exponential Euler *** far as we know,the weak error analysis for approximations of fractional noise driven SPDEs is absent in the literature.A key difficulty in the analysis is caused by the lack of the associated Kolmogorov *** the present work,a novel and efficient approach is presented to carry out the weak error analysis for the approximations,which does not rely on the associated Kolmogorov equations but relies on the Malliavin *** the best of our knowledge,the rates of weak convergence,shown to be higher than the strong convergence rates,are revealed in the fractional noise driven SPDE setting for the first *** examples corroborate the claimed weak orders of convergence.

关键词： Parabolic SPDEs Fractional Brownian motion Weak convergence rates Spec-tral Galerkin method Exponential Euler method Malliavin calculus

Production of linear alkylbenzene over Ce containing Beta zeolites

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Chinese Journal of Chemical Engineering 2024年第3期67卷 220-227页

作者： Shiqi Zhang Shengzhi gan Baoyu Liu Jinxiang Dong School of Chemical Engineering and Light Industry Guangdong Provincial Key Laboratory of Plant Resources BiorefineryGuangzhou Key Laboratory of Clean Transportation Energy ChemistryGuangdong University of TechnologyGuangzhou 510006China Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory(Rongjiang Laboratory) Jieyang 515200China

Ce-encapsulated Beta zeolite was synthesized by a one-pot hydrothermal method with citric acid complexing Ce in the absence of Na *** citric acid can effectively prevent the deposition of Ce species during the hydrothermal synthesis of zeolites,leading to uniform distribution of Ce cluster in the framework of Beta ***,the sodium-free synthesis system resulted that the Brønsted acid sites were mainly located on the straight channels and external surface of Beta zeolites,improving the utilization of Brønsted acid *** addition,Ce encapsulated Beta zeolites showed enhanced activity and robust stability in the alkylation of benzene with 1-dodecene based on the synergistic effect between Ce species and Brønsted acid sites,which pave the way for its practical application in the production of alkylbenzene.

关键词： Beta zeolites Catalysis Alkylation Long-chain olefins

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应用磁环抑制输电线路短波频段无源干扰

高电压技术 2017年第5期43卷 1722-1728页

作者：干喆渊王延海张建功赵志斌李煜磊中国电力科学研究院电网环境保护国家重点实验室武汉430074 国家电网公司北京100031 华北电力大学新能源电力系统国家重点实验室北京102206 国网湖北省电力公司检修公司武汉430050

架空线路作为金属导体会对空间的无线电信号产生电磁散射,从而对邻近的无线电设施造成影响。为了降低架空输电线路对工作在短波频段无线电台站接收效果的影响,提出了在架空输电线上感应电流峰值位置加装磁环的方法,以抑制其对短波无线... 详细信息

架空线路作为金属导体会对空间的无线电信号产生电磁散射,从而对邻近的无线电设施造成影响。为了降低架空输电线路对工作在短波频段无线电台站接收效果的影响,提出了在架空输电线上感应电流峰值位置加装磁环的方法,以抑制其对短波无线电台站的影响。该方法首先计算实际架空线路在无线电台站电磁波入射情况下的感应电流分布,然后在架空输电线上感应电流若干峰值位置加装磁环,从而实现抑制架空线路对邻近无线电台站无源干扰的影响。该方法的有效性在武汉特高压交流试验基地开展的无源干扰试验中进行了验证。研究结果表明:应用磁环降低电磁散射影响的效果与磁环的阻抗特性和安装位置相关,并且抑制效果随磁环数量增加呈现饱和现象;磁环的选择需考虑短波发射台或接收台的工作频率,尽量选择在工作频率点阻抗较大的磁环;磁环的安装位置要选择线路上感应电流最大值的位置。

关键词：输电线路无线电台站无源干扰磁环感应电流抑制措施电磁散射