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Achieving enhanced energy storage performance and ultra-fast discharge time in tungsten–bronze ceramic

Journal of Advanced Ceramics 2024年第9期13卷 1349-1358页

作者： Yuejun Dan Liupan Tang wenzhi ning Yingzhi Meng Changzheng Hu Laijun Liu Liang Fang Key Laboratory of New Processing Technology for Nonferrous Metal&Materials Ministry of EducationCollege of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004China Guangxi Key Laboratory of Optical and Electronic Materials and Devices Guilin University of TechnologyGuilin 541004China Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi Guilin University of TechnologyGuilin 541004China

The rapid development of capacitors with high energy density and efficiency has been driven by advanced electronic systems and innovative pulsed power *** this study,we prepared Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=2.5,3,3.5,4,4.5)dielectric ceramics,which exhibited structural distortion due to the co-occupation of Ba^(2+),Sr^(2+),and Sm^(3+)in the A-site and the partial substitution of Nb^(5+)by Zr^(4+)in the *** ordered/disordered distribution due to these distortions thus generated polar nanoregions(PNRs)and induced a relaxation ferroelectric behavior,which was verified by the high-resolution transmission electron *** the use of the Vogel–Fulcher and Maxwell–Boltzmann equations,we found that easy inversion and small dipole sizes are crucial for achieving high energy storage density and *** Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)dielectric ceramic displayed a ferroelectric/paraelectric transition near room *** ferroelectric testing revealed large energy storage density(Wrec=4.31 J·cm^(−3))and high efficiency(η=93.8%)at 310 kV·cm−***,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=4.5)exhibited higher breakdown field strength due to its large resistivity and small grain *** led to energy storage density of approximately 5.3 J·cm^(−3)at 460 kV·cm^(−1).Additionally,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)demonstrated current density(CD)of approximately 713.38 A·cm^(−2)and power density(PD)of approximately 87.51 MW·cm^(−3),with ultrafast discharge time of 34 ns and excellent discharge energy density(Wdis)of approximately 2.27 J·cm^(−3).Overall,this study presents a promising approach for developing dielectric ceramic materials that hold potential for applications in innovative pulsed power components.

关键词： large energy storage high efficiency ultra-fast discharge time tungsten-bronze structure

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Soil organic carbon storages and bacterial communities along a restored mangrove soil chronosequence in the Jiulong River Estuary:From tidal flats to mangrove afforestation

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Fundamental Research 2023年第6期3卷 880-889页

作者： Feifei Wang Rui Guo ning Zhang Shengchang Yang wenzhi Cao State Key Laboratory of Marine Environmental Science Key Laboratory of the Ministry of Education for Coastal and Wetland EcosystemsCollege of Environment and EcologyXiamen UniversityXiamenFujian 361102China

Among many ecological services provided by mangrove ecosystems,soil organic carbon(SOC)storages have recently received much attention owing to the increasing atmospheric partial pressure of dissolved CO_(2)(pCO_(2)).Bacteria are fundamental to ecosystem functions and strongly influence the coupling of coastal carbon,nitrogen,and sulfur cycling in *** SOC storage and bacterial communities along a restored mangrove soil chronosequence in the Jiulong River Estuary were explored using the 16S rDNA sequencing *** results showed the SOC storage in the 100 cm soil profile was 103.31±5.87 kg C m^(−2)and 93.10±11.28 kg C m^(−2)for mangroves with afforestation ages of 36 and 60 years,*** total nitrogen(TN)and total sulfur(TS)contents exhibited significant correlations with the SOC in the mangrove soils,but only TN and SOC showed significant correlation in tidal flat *** the tidal flats and mangroves occupied the contiguous intertidal zone within several kilometers,the variations in the SOC storage along the restored mangrove soil chronosequence were notably *** Functional Annotation of Prokaryotic Taxa(FAPROTAX)database was used to annotate the metabolic functions of the bacteria in the *** annotation revealed that only four metabolic functions were enriched with a higher relative abundance of the corresponding bacteria,and these enriched functions were largely associated with sulfate *** addition,the specifically critical bacterial taxa that were associated with the SOC accumulation and nutrient cycling,shaped the distinct metabolic functions,and consequently facilitated the SOC accumulation in the mangrove soils with various afforestation *** general homogenization of the microbial community and composition along the intertidal soil chronosequence was primarily driven by the reciprocating tidal flows and geographical contiguity.

关键词： Soil organic carbon storage Bacterial communities Bacterial ecological functions Mangrove afforestation Tidal flats

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Simulating the ion permeation and ion selection for a eukaryotic voltage-gated sodium channel NavPaS

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Protein & Cell 2018年第6期9卷 580-585页

作者： Juanrong Zhang wenzhi Mao Yanhui Ren Rui-ning Sun Nieng Yan Haipeng Gong MOE Key Laboratory of Bioinformatics School of Life Sciences Tsinghua University Beijing 100084 China Beijing Advanced Innovation Center for Structural Biology Tsinghua University Beijing 100084 China State Key Laboratory of Membrane Biology School of Life Sciences Tsinghua University Beijing 100084 China

Dear Editor, Voltage-gated sodium （Nav） channels are membrane pro- teins that are responsible for the propagation of action potentials in mammals by mediating Na~ influx in excitable cells such as nerve and muscle. In human, Nay channels are therapeutic targets as their mutations con- tribute to many diseases. Structures of prokaryotic Nay channels, e.g., NavAb （Payandeh et al., 2011）, NavRh （Zhang et al., 2012） and NavMs （Mccusker et al., 2012）, were successively determined in the past years. Recently, the cryo-EM structures of two eukaryotic Nay channels were reported （Shen et al., 2017; Yan et al., 2017）. Nay channels contain 24 transmembrane helices.

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Prey decline leads to diet shift in the largest population of Indo-Pacific humpback dolphins?

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Integrative Zoology 2021年第4期16卷 548-574页

作者： wenzhi LIN Leszek KARCZMARSKI Ruilian ZHOU Yaqian MO Lang GUO Sam King Fung YIU Xi ning Tak-Cheung WAI Yuping WU School of Marine Sciences Zhuhai Key Laboratory of Marine Bioresources and EnvironmentGuangdong Provincial Key Laboratory of Marine Resources and Coastal EngineeringSouthern Marine Science and Engineering Guangdong LaboratorySun Yat-Sen UniversityZhuhaiChina Division of Cetacean Ecology Cetacea Research InstituteLantauHong Kong SARChina Marine Mammal and Marine Bioacoustics Laboratory Institute of Deep-sea Science and EngineeringChinese Academy of SciencesSanyaChina School of Biological Sciences University of Hong KongPokfulamHong Kong SARChina State Key Laboratory of Marine Pollution City University of Hong KongHong Kong SARChina

The Pearl River Delta(PRD)region on the southeast coast of China has long been known as a highly productive fishing *** the late 1980s,fishing pressure in the PRD has been intense,which warrants concerns of potential fishery-related impacts on the food resources and foraging ecology of apex marine predators in this region,such as the Indo-Pacific humpback dolphin(Sousa chinensis).In this study,we examined 54 stomachs with food remains,collected from beached carcasses of humpback dolphins recovered during fifteen years between 2003 and *** 6043 identified prey items represent 62 teleost taxa,primarily small estuarine fish,but also larger reef *** dolphins appear to be opportunistic foragers,hunting across the water-column,with preference for shoaling and meaty fishes(*** lucidus IRI%=38.6%,Johnius belangerii IRI%=23.1%,Mugil cephalus IRI%=14.0%).Our findings suggest a dietary shift in recent years,from primarily demersal(as previously reported)to greater intake of neritic and pelagic *** foraging group size has decreased in recent years,which corresponds with declining size and numbers of prey items retrieved from dolphin *** suggest that these are indicators of declining food *** with a shortage of preferred prey,humpback dolphins may have broadened their dietary spectrum to maintain their daily energy intake,while their foraging group size decreased in response to the altered tradeoff between the costs and benefits of group foraging.

关键词： feeding ecology Pearl River Delta prey decline Sousa chinensis stomach content analysis

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Shifting from homogeneous to heterogeneous surfaces in estimating terrestrial evapotranspiration: Review and perspectives

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Science China Earth Sciences 2022年第2期65卷 197-214页

作者： Yuanbo LIU Guoyu QIU Hongsheng ZHANG Yonghui YANG Yinsheng ZHANG Quan WANG wenzhi ZHAO Li JIA Xibin JI Yujiu XIONG Chunhua YAN ning MA Shumin HAN Yifan CUI Nanjing Institute of Geography and Limnology Chinese Academy of SciencesNanjing 210008China School of Environment and Energy Peking University Shenzhen Graduate SchoolShenzhen 518055China Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100081China Key Laboratory for Agricultural Water Resources Center for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyChinese Academy of SciencesShijiazhuang 050022China Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China Faculty of Agriculture Shizuoka UniversityShizuoka 422-8529Japan Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000China Key Laboratory of Ecohydrology of Inland River Basin Chinese Academy of SciencesLanzhou 730000China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China School of Civil Engineering Sun Yat-Sen UniversityGuangzhou 510275China Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Terrestrial evapotranspiration(ET)is a crucial link between Earth’s water cycle and the surface energy *** measurement and estimation remain a major challenge in geophysical,biological,and environmental *** work,represented by Dalton and Penman,and the development of theories and experiments on turbulent exchange in the atmospheric boundary layer(ABL),laid the foundation for mainstream methodologies in ET *** the 1990s,eddy covariance(EC)systems and satellite remote sensing have been widely applied from cold to tropical and from arid to humid *** cover water surfaces,wetlands,forests,croplands,grasslands,barelands,and urban areas,offering an exceptional number of reports on diverse ET *** nocturnal ET,hysteresis between ET and environmental forces,turbulence intermittency,island effects on heterogeneous surfaces,and phase transition between underlying surfaces are examples of reported new phenomena,posing theoretical and practical challenges to mainstream ET ***,based on non-conventional theories,new methods have emerged,such as maximum entropy production and nonparametric ***,high-frequency on-site observation and aerospace remote sensing technology in combination form multi-scale observations across plant stomata,leaves,plants,canopies,landscapes,and *** promotes an insightful understanding of diverse ET processes and synthesizes the common mechanisms of the processes between and across spatial and temporal *** the recent achievements in conception,model,and technology serve as the basis for breaking through the known difficulties in ET *** expect that they will provide a rigorous,reliable scientific basis and experimental support to address theoretical arguments of global significance,such as the water-heat-carbon cycle,and solve practical needs of national importance,including agricultural irrigation and food security,precise manageme

关键词： Evapotranspiration Atmospheric boundary layer Heterogeneous surface Uncertainty

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Hybrid Modulation Strategy with Voltage Balancing Control for Four-level Neutral-point Clamped Converters

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Chinese Journal of Electrical Engineering 2024年第3期10卷 25-36页

作者： ning Xie Wei Zhao wenzhi Lin Zhenglei Wang Yukai Chen Chengzhi Li Jianfei Chen Digital Grid Research Institute Co. Ltd.China Southern Power GridGuangzhou 510700China School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China

Capacitor voltage imbalance in four-level(4L)neutral-point clamped(NPC)converters is a direct factor hindering their *** particular,when they are applied in motor drives,space vector pulse-width modulation(SVPWM)is a more popular scheme,but conventional 4L SVPWM cannot achieve the voltage balancing control of DC-link capacitors,is complex to implement,and requires costly computation.A hybrid modulation method with capacitor voltage-balancing control for 4L NPC converters is *** proposed method is achieved using three-level(3L)SVPWM and two-level(2L)carrier-based pulse-width modulation(CPWM)based on the concept of"4L=3L+2L".Thus,it can be easily implemented on a digital chip because the modulation process is nearly identical to that of 3L SVPWM without the more cumbersome 4L SVPWM ***,any proven optimization scheme of 3L SVPWM can be directly applied to the proposed method to further improve *** and experimental results for a 4L active NPC converter demonstrate the effectiveness of the proposed method.

关键词： 4L NPC converters 3L SVPWM 2L CPWM voltage balancing control

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圆柱形谐振管内非线性驻波的有限体积计算方法

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机械工程学报 2012年第16期48卷 116-121页

作者：宁方立张文治董梁西北工业大学机电学院西安710072

提出一种用于求解圆柱形谐振管内非线性驻波的有限体积计算方法。谐振管内初始为自由状态的流体被整体谐振激励,当激励频率与谐振管内声场固有频率一致时,谐振管内将产生非线性驻波。建立整体振动条件下谐振管内瞬态可压缩热粘性牛顿流... 详细信息

提出一种用于求解圆柱形谐振管内非线性驻波的有限体积计算方法。谐振管内初始为自由状态的流体被整体谐振激励,当激励频率与谐振管内声场固有频率一致时,谐振管内将产生非线性驻波。建立整体振动条件下谐振管内瞬态可压缩热粘性牛顿流体的一维Navier-Stokes模型方程的积分方程;在时域上,通过SIMPLEC方法(以压力为基础的有限体积法)和交错网格技术推导出离散化代数方程组,并进行求解。当谐振管内的流体为R-12气体,在整体振动的条件下,利用提出的方法对谐振管内的非线性驻波进行求解,通过与现有文献中伽辽金方法的计算结果进行对比,所得到的非线性驻波声压在波形和幅值方面都与这些结果非常吻合,从而验证了该方法的可行性。得到谐振管左端处的绝对压力波形、温度波形和声压频谱响应等物理特性分布;同时得到谐振管内不同位置处的速度变化,发现在谐振管两端出现了速度钉状波形;有限体积计算方法为解决强声密封的非线性驻波的数值计算奠定了良好基础。

关键词：谐振管非线性驻波有限体积法强声密封

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硅橡胶/半导电复合界面特高频信号传播特性仿真

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高电压技术 2015年第10期41卷 3326-3331页

作者：常文治阎春雨毕建刚杨圆杨宁中国电力科学研究院北京100192

硅橡胶/半导电复合界面是导致电缆中间接头内部局部放电特高频电磁波衰减的主要结构,分析该界面上特高频电磁波的传播特征,能够为中间接头局部放电特高频检测提供理论依据。为研究局部放电特高频电磁波在电缆中间接头内的传播规律,通过... 详细信息

硅橡胶/半导电复合界面是导致电缆中间接头内部局部放电特高频电磁波衰减的主要结构,分析该界面上特高频电磁波的传播特征,能够为中间接头局部放电特高频检测提供理论依据。为研究局部放电特高频电磁波在电缆中间接头内的传播规律,通过合理简化,建立了硅橡胶/半导电复合界面外敷金属屏蔽网的计算机仿真模型,在硅橡胶介质中设置高斯脉冲电流激励源模拟硅橡胶绝缘的内部放电,基于时域有限差分法仿真分析了激励信号源产生的特高频电磁波在经过硅橡胶/半导电复合界面后时域及频域特征的变化特点,得到了特高频电磁波在典型位置处场强的时域、频域波形以及在硅橡胶/半导电复合界面传播的动态过程。研究结果表明,针对该仿真模型,特高频电磁波强度在经过半导电层和铜网屏蔽层后衰减了约50倍;电磁波在经过硅橡胶/半导电复合界面后频谱范围变化较小,但其能量峰值明显向高频段发展,证明了特高频电磁波在硅橡胶/半导电复合界面上发生明显的衰减和畸变,但其中的高频成分能够向外部空间继续传播。

关键词：硅橡胶半导电层屏蔽层特高频电磁波时域有限差分传播特性

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周期节流扰动下激波串振荡流动的数值模拟

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航空动力学报 2023年第4期38卷 994-1004页

作者：高文智赵鹏飞宁重阳田野聂宝平李祝飞合肥工业大学机械工程学院合肥230009 中国空气动力研究与发展中心高超声速冲压发动机技术重点实验室四川绵阳621000 中国科学技术大学工程科学学院合肥230027

基于动网格方法数值模拟并分析来流马赫数为6,二元进气道/隔离段构型在频率为50~500 Hz周期节流下的激波串振荡流动。结果表明:当节流比在0.2~0.32范围内周期变化时,隔离段出现与节流频率相同的激波串振荡现象。节流频率会影响激波串振... 详细信息

基于动网格方法数值模拟并分析来流马赫数为6,二元进气道/隔离段构型在频率为50~500 Hz周期节流下的激波串振荡流动。结果表明:当节流比在0.2~0.32范围内周期变化时,隔离段出现与节流频率相同的激波串振荡现象。节流频率会影响激波串振荡幅度和壁面压强波动特性。50 Hz与100 Hz工况的激波串流向振幅相近,100~500 Hz范围内随频率增加,流向振幅从15.5 mm减小至10.8 mm。壁面压强随频率的变化规律更加复杂,以凹腔中部为界,其上游壁面压强时均值、均方差峰值整体随频率增加而降低,其中50 Hz工况唇口侧壁面压强均方差峰值可达21倍来流静压,但其下游壁面压强无明显规律。分析表明节流频率对激波串振荡的影响与节流扰动的传播时间相关,工程设计中需综合考虑构型与反压参数对激波串振荡的影响。

关键词：高超声速进气道隔离段动态反压激波串振荡脉动压强

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教学过程与生产过程对接的实践教学体系构建与实现

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实验室研究与探索 2019年第3期38卷 206-209页

作者：孙文志黄玮李宁王斅辽宁石油化工大学工程训练中心辽宁抚顺113001 辽宁石油化工大学教务处辽宁抚顺113001

教学过程与生产过程对接是高校实践教学改革的重要环节,是产教融合、协同育人的关键所在。分析了普通高校实践教学存在的突出问题,重新构建了以实践基地建设为依托,在教学内容的职业化分析、训练过程的规范化养成、评价体系的多元化运... 详细信息

教学过程与生产过程对接是高校实践教学改革的重要环节,是产教融合、协同育人的关键所在。分析了普通高校实践教学存在的突出问题,重新构建了以实践基地建设为依托,在教学内容的职业化分析、训练过程的规范化养成、评价体系的多元化运作、指导教师的行业化参与等方面进行全面改革与实践,建立了全新的实践教学新模式。通过1年多的运行实践,学生的专业技能和职业能力得到了较大提升,就业竞争力明显增强,创新能力得到了很好的锻炼,达到了预期的效果。

关键词：实践教学化工安全工艺流程生产过程职业标准

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