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Filter Design of Wireless Base Station Power Supply

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ZTE Communications 2024年

作者： LI Wei GUO Wei wang zhida ZTE Corporation

The design of electromagnetic interference (EMI) filters needs to fulfill the EMI standards. Designing a filter is a time-consuming process for new engineers as well as for those experienced engineers. This paper measured and compared the noise spectrum of the wireless base station power prototype with and without the original filter. The ideal insertion loss (IL) of the original filter is obtained by combining calculation and simulation. It is pointed out that the effect of the original filter is not good. Based on the improved insertion-loss method， the source impedance model of the prototype is established by combining measurement and theory. A procedure for designing EMI filters for switch power supply will be presented. The filter design procedure makes it possible to design filters quickly and easily. Finally， the proposed filter design method is proved to be effective by the EMI measurement of the wireless base station power supply prototype.

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Exploring precursor effect in in-situ reconstruction of Bi metal organic-frameworks during CO_(2)electroreduction reaction to tailor formate selectivity towards 100%

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Science China Chemistry 2024年第7期67卷 2190-2198页

作者： zhida Liu Qikui Fan Hang Huo Fanglei Yao Xiaoping Gao Jin wang College of Materials Science and Engineering Shenzhen UniversityShenzhen 518071China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Key Laboratory of Functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China

Bi-based metal-organic frameworks(Bi-MOFs)as efficient catalysts for the CO_(2)electroreduction reaction(CRR)have been extensively investigated.It has been established that Bi-MOFs usually undergo in-situ transformation during the CRR,ultimately converting into Bi nanostructures.However,the effect of the MOF precursors on the structure of the derived Bi catalysts and consequently on their electrocatalytic properties has not been clearly elucidated.In this work,we prepared four variants of a novel Bi-MOF with different morphologies and dimensions,and explored the effects of the precursors on the resulting Bi catalysts and their CRR performance.A precursor-dependent in-situ transformation and its profound impact on tuning the CO_(2)-formate FE towards~100%have been revealed.Among the four examined variants,Bi-MOF with nanocube-like morphology(BiMOF-NC)is transformed into thin and flat Bi nanosheets capable of successfully enveloping the fibers of carbon paper(working electrode),while the other three variants with increased size and dodecahedral/octahedral geometry have been transformed into Bi nanoflowers,exposing a fair portion of the carbon fibers in the working electrode.Furthermore,the transformation rate was found to be dependent on the precursors and BiMOF-NC exhibited the highest rate of reconstruction compared with other samples.Consequently,the Bi catalyst derived from BiMOF-NC delivered a selectivity for the formate product of nearly 100%at-1.2 V(vs.reversible hydrogen electrode(RHE))and of over 95%in a wide potential range due to efficient suppression of the competing hydrogen evolution reaction(HER)over carbon fibers.The in-situ transformed BiMOFNC also demonstrated equivalently high formate selectivity at large current densities(≥100 mA cm^(-2))in flow cell reactors as that in H-type reactors,underscoring its potential for industrial applications.This work highlights the necessity of finely tuning the structural features of MOF precursors to achieve optimized electrocatalytic performance.

关键词： Bi-MOFs precursor effect in-situ transformation Bi nanosheets CO2-to-formate

Layered kagome compound Na_(2)Ni_(3)S_(4)with topological flat band

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Chinese Physics B 2024年第5期33卷 153-159页

作者：叶君耀林益浩王浩哲宋志达冯济谢韦伟贾爽 International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Department of Chemistry Michigan State UniversityMI48824USA Hefei National Laboratory Hefei 230088China Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials Peking UniversityBeijing 100871China

We report structural and electronic properties of Na_(2)Ni_(3)S_(4),a quasi-two-dimensional compound composed of alternating layers of[Ni_(3)S_(4)]^(2-)and Na^(+).The compound features a remarkable Ni-based kagome lattice with a square planar configuration of four surrounding S atoms for each Ni atom.Magnetization and electrical measurements reveal a weak paramagnetic insulator with a gap of about 0.5 eV.Our band structure calculation highlights a set of topological flat bands of the kagome lattice derived from the rotated dxz-orbital with C_(3)+T symmetry in the presence of crystal-field splitting.

关键词： kagome lattice flat band

Effects of Dietary Protein and Lipid Levels on Growth Performance, Muscle Composition, Immunity Index and Biochemical Index of the Greenfin Horse-Faced Filefish (Thamnaconus septentrionalis) Juvenile

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Journal of Ocean University of China 2021年第5期20卷 1245-1252页

作者： XU Zhengxin ZHANG Pengfei CHANG Qing CHEN Siqing BIAN Li wang zhida Yellow Sea Fisheries Research Institute Chinese Academy of Fishery ScienceLaboratory for Marine Fisheries Science and Food Production ProcessesPilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266071China College of Marine Science and Fisheries Jiangsu Ocean UniversityLianyungang 222005China College of Fisheries and Life Science Shanghai Ocean UniversityShanghai 201306China Qingdao Yuehaiwan Marine Industry Development Co. Ltd.Qingdao 266200China

The effects of different dietary protein and lipid levels on juvenile greenfin horse-faced filefish(Thamnaconus septentrionalis)was experimentally evaluated in a 56-day study.Fish(initial weight 6.47±0.56 g)were fed with nine different diet combinations containing three varying levels of protein(37%,43%,49%)and lipids(4%,7%,10%)in triplicates,where the protein-to-energy(P/E)ratios of the diets varied in the range of 19.17-26.99mgkJ−1.Results showed that fish fed diets containing 49%protein and 10%lipid exhibited significantly lower feed intake than those fed other diets.The weight gain of fish fed diets with 43%protein was significantly higher than that of fish fed 37%or 49%protein diets.While no significant change in weight gain was observed when lipid content was increased from 4%to 7%,weight gain decreased significantly when lipid increased from 7%to 10%.The protein efficiency ratio and feed efficiency were highest when the fish were fed the diet with 49%protein and 7%lipids.Muscle crude lipid content was positively correlated with dietary protein level regardless of lipid level.The diet of 43%protein or 7%lipids significantly reduced the activity of alanine aminotransferase and aspartate aminotransferase in liver.The contents of aspartate aminotransferase,superoxide dismutase and malondialdehyde were significantly increased from 4%to 10%lipids in plasma.The plasma total cholesterol and triglyceride contents were positively correlated with dietary lipid level at the same protein level.Our comprehensive analysis concluded that a diet with 43%protein and 7%lipid,with a P/E ratio of 23.07mgkJ−1,significantly promote the growth performance,feed utilization and health of juvenile greenfin horse-faced filefish.

关键词： greenfin horse-faced filefish protein lipid growth

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基于有机/无机双层忆阻器的人工光电神经元

光子学报 2024年第4期53卷 257-266页

作者：赖秉琳李志达李博文王弘禹张国成福建理工大学微电子技术研究中心福州350108

提出了一种基于Ag/IDTBT/ZnO/Si忆阻器的人工神经元器件,该器件开关比约为102~103且有较低的工作电压。该器件能够模拟泄漏集成点火的神经元模型。此外,研究了IDTBT浓度对人工神经元器件性能的影响。结果表明:IDTBT浓度的增加会导致薄... 详细信息

提出了一种基于Ag/IDTBT/ZnO/Si忆阻器的人工神经元器件,该器件开关比约为102~103且有较低的工作电压。该器件能够模拟泄漏集成点火的神经元模型。此外,研究了IDTBT浓度对人工神经元器件性能的影响。结果表明:IDTBT浓度的增加会导致薄膜厚度的增加,进而会使得神经元器件的阈值电压升高以及积分点火所需要的幅值电压变大。当有光照射之后,器件的阈值电压会明显降低。在器件储存了30天后重新测试,器件性能没有明显的变化,说明该器件具有良好的稳定性。本工作为促进神经形态系统的发展提供了有效的策略。

关键词：人工神经元忆阻器 ZnO IDTBT 光照

小剪跨比铁路圆端桥墩拟静力试验及易损性分析

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铁道科学与工程学报 2024年第1期21卷 228-240页

作者：沈林白洪彧周志达王涵玉蒲黔辉文旭光西南交通大学土木工程学院四川成都610031 广西中国−东盟综合交通国际联合重点实验室南宁学院广西南宁530000

为厘清小剪跨比圆端铁路桥墩横桥向的地震损伤机理,以国内某铁路沿线桥梁为参考开展3组缩尺比1∶8的拟静力试验,对滞回曲线的延性、残余位移、滞回耗能和刚度退化4个方面进行分析,以试验结果为参考使用OpenSees建立纤维截面有限元模型... 详细信息

为厘清小剪跨比圆端铁路桥墩横桥向的地震损伤机理,以国内某铁路沿线桥梁为参考开展3组缩尺比1∶8的拟静力试验,对滞回曲线的延性、残余位移、滞回耗能和刚度退化4个方面进行分析,以试验结果为参考使用OpenSees建立纤维截面有限元模型并进行耐震时程动力计算,以桥墩的位移延性比为损伤指标,基于试验中观察得到的4个关键节点定义无、轻微、中度、严重和完全损伤5种损伤状态之间的位移延性比临界值,通过易损性分析桥墩的损伤发展历程。研究结果表明:1)配筋率从0.3%提升至0.7%,桥墩的承载能力提高至1.37倍,极限位移提高至1.22倍,最终残余位移提高至1.55倍,耗散能量增加至1.80倍,初始刚度提升至1.08倍,最终刚度提升至1.12倍。提高配筋率可以提升桥梁抗震性能,也能增加桥梁抗震韧性。2)当桥墩配筋率由0.3%提至0.7%时,在多遇地震下,轻微损伤概率从87.2%降为29.8%;在设计地震下,中度损伤的概率从63.5%降为30.0%;在罕遇地震下,严重损伤的概率从61.7%降为16.4%。纵筋配筋率可以大幅降低桥墩的损伤概率,提升桥墩的抗震性能。3)在现行铁路规范允许的延性系数为4.8时,3个桥墩均处于严重损伤的阶段。当发生罕遇地震时,3个桥墩出现完全破坏的概率为6.4%、0和1.4%,小剪跨比圆端铁路桥墩在强震作用下具有一定的抗震安全储备。

关键词：圆端形桥墩小剪跨比拟静力试验弯剪破坏易损性

Insights into multidimensional transport flux from vertical observation and numerical simulation in two cities in North China

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Journal of Environmental Sciences 2023年第3期125卷 831-842页

作者： zhida Zhang Xiaoqi wang Shuiyuan Cheng Guiqian Tang Yibin Fu Key Laboratory of Beijing on Regional Air Pollution Control Beijing University of TechnologyBeijing 100124China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China

This study represents the first quantitative evaluation of pollution transport budget within the boundary layer of typical cities in the Beijing-Tianjin-Hebei (BTH) region from the perspective of horizontal and vertical exchanges and further discusses the impact of the atmospheric boundary layer (ABL)-free troposphere (FT) exchange on concentration of fine particulate matter (PM_(2.5)) within the ABL during heavy pollution.From the perspective of the transport flux balance relationship,differences in pollution transport characteristics between the two cities is mainly reflected in the ABL-FT exchange effect.The FT mainly flowed into the ABL in BJ,while in SJZ,the outflow from the ABL to the FT was more intense.Combined with an analysis of vertical wind profile distribution,BJ was found to be more susceptible to the influence of northwest cold high prevailing in winter,while sinking of strong cold air allowed the FT flowing into the ABL influence the vertical exchange over BJ.In addition,we selected a typical pollution event for targeted analysis to understand mechanistic details of the influence of ABL-FT exchange on the pollution event.These results showed that ABL-FT interaction played an important role in PM_(2.5)concentration within the ABL during heavy pollution.Especially in the early stage of heavy pollution,FT transport contributed as much as 82.74% of PM_(2.5)within the ABL.These findings are significant for improving our understanding of pollution transport characteristics within the boundary layer and the effect of ABL-FT exchange on air quality.

关键词： Transport flux Horizontal transport Vertical exchange Atmospheric boundary layer Free troposphere Pollutant budget relationship

基于语义分割和融合残差U⁃Net的单视光学遥感影像三维重建方法

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数据采集与处理 2024年第2期39卷 348-360页

作者：黄桦朱宇昕章历陈志达张乙志王博浙江省测绘科学技术研究院杭州310012 南京航空航天大学航天学院南京211106 浙江艺佳地理信息技术有限公司杭州311700 绍兴市上虞区自然资源监测中心绍兴312365

从单视遥感图像进行三维重建本身是一个解不唯一的非适定问题,往往需要大量的人工经验来补充缺失信息以构建完整三维模型。为了解决这一问题,提出了一种基于语义分割和融合残差U-Net的单视遥感影像三维重建方法。该方法包括语义分割和... 详细信息

从单视遥感图像进行三维重建本身是一个解不唯一的非适定问题,往往需要大量的人工经验来补充缺失信息以构建完整三维模型。为了解决这一问题,提出了一种基于语义分割和融合残差U-Net的单视遥感影像三维重建方法。该方法包括语义分割和单视遥感影像高度估计两个阶段。语义分割阶段使用U-Net确定地物属性,在此基础上改进U-Net对遥感影像进行高度估计,并联合语义特征进行锚定高度回归以提高重建精度。针对改进U-Net,通过嵌入不同数量与通道的残差块,强化编码器的特征提取能力,并修改解码器输出层使其适应于高度回归任务,从而实现逐像素预测遥感影像的数字表面模型(Digital surface model,DSM)高度值。在公开的US3D数据集上得到了均方根误差(Root mean square error,RMSE)为2.751 m、平均绝对误差(Mean absolute error,MAE)为1.446 m的结果,重建结果均优于其余网络,证实该方法实现了基于单视遥感影像的三维估计,能够重建地物的分布结构。

关键词：语义分割深度残差学习融合残差U-Net 单视三维重建

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采用瞄准式杀伤技术的防空导弹总体问题研究

现代防御技术 2024年第2期52卷 42-52页

作者：王志达薛林陈阳阳李建国北京电子工程总体研究所北京100854 中国长峰机电技术研究设计院北京100854

定向战斗部技术是利用目标方位信息通过导弹弹体变化或战斗部起爆逻辑控制改变爆破方向以取得最大毁伤效果的新型杀伤技术,是未来新一代防空导弹实现能力跨越的关键技术之一。以装备有径向转向式定向战斗部的瞄准杀伤式防空导弹为研究对... 详细信息

定向战斗部技术是利用目标方位信息通过导弹弹体变化或战斗部起爆逻辑控制改变爆破方向以取得最大毁伤效果的新型杀伤技术,是未来新一代防空导弹实现能力跨越的关键技术之一。以装备有径向转向式定向战斗部的瞄准杀伤式防空导弹为研究对象,着重研究了相关总体问题。研究了补偿导弹法向过载的脱靶信息预测方法,满足了瞄准式杀伤提前获取脱靶信息的需求;研究了预测着靶点的散布规律和预测模糊问题的形成机理,为解决模糊问题提供了理论支撑;研究了小脱靶量遭遇时的瞄准精确度提升方法;对瞄准杀伤式防空导弹实例进行了仿真。

关键词：瞄准式杀伤技术脱靶信息预测预测模糊机理冗余杀伤偏置控制