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Moderate Fields, Maximum Potential: Achieving High Records with Temperature‑Stable Energy Storage in Lead‑Free BNT‑Based Ceramics

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Nano-Micro Letters 2024年第5期16卷 184-200页

作者： Wenjing shi Leiyang Zhang Ruiyi Jing Yunyao Huang Fukang Chen Vladimir Shur xiaoyong Wei Gang Liu Hongliang Du Li Jin Electronic Materials Research Laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China School of Materials and Energy Southwest UniversityChongqing 400715People’s Republic of China School of Natural Sciences and Mathematics Ural Federal UniversityEkaterinburg 620000Russia Multifunctional Electronic Ceramics Laboratory College of EngineeringXi’an International UniversityXi’an 710077People’s Republic of China

The increasing awareness of environmental concerns has prompted a surge in the exploration of leadfree,high-power ceramic capacitors.Ongoing efforts to develop leadfree dielectric ceramics with exceptional energystorage performance(ESP)have predominantly relied on multicomponent composite strategies,often accomplished under ultrahigh electric fields.However,this approach poses challenges in insulation and system downsizing due to the necessary working voltage under such conditions.Despite extensive study,bulk ceramics of(Bi_(0.5)Na_(0.5))TiO_(3)(BNT),a prominent lead-free dielectric ceramic family,have seldom achieved a recoverable energy-storage(ES)density(Wrec)exceeding 7 J cm^(−3).This study introduces a novel approach to attain ceramic capacitors with high ESP under moderate electric fields by regulating permittivity based on a linear dielectric model,enhancing insulation quality,and engineering domain structures through chemical formula optimization.The incorporation of SrTiO_(3)(ST)into the BNT matrix is revealed to reduce the dielectric constant,while the addition of Bi(Mg_(2/3)Nb_(1/3))O_(3)(BMN)aids in maintaining polarization.Additionally,the study elucidates the methodology to achieve high ESP at moderate electric fields ranging from 300 to 500 kV cm^(−1).In our optimized composition,0.5(Bi_(0.5)Na_(0.4)K_(0.1))TiO_(3)–0.5(2/3ST-1/3BMN)(B-0.5SB)ceramics,we achieved a Wrec of 7.19 J cm^(−3) with an efficiency of 93.8%at 460 kV cm^(−1).Impressively,the B-0.5SB ceramics exhibit remarkable thermal stability between 30 and 140℃ under 365 kV cm^(−1),maintaining a Wrec exceeding 5 J cm^(−3).This study not only establishes the B-0.5SB ceramics as promising candidates for ES materials but also demonstrates the feasibility of optimizing ESP by modifying the dielectric constant under specific electric field conditions.Simultaneously,it provides valuable insights for the future design of ceramic capacitors with high ESP under constraints of limited electric field.

关键词： BNT Energy storage Lead-free Relaxor ferroelectrics Capacitors

Nutrient Structure of the Taiwan Warm Current and Estimation of Vertical Nutrient Fluxes in Upwelling Areas in the East China Sea in Summer

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中国海洋大学学报：英文版 2014年第4期13卷 613-620页

作者： shi xiaoyong LI Hongmei WANG Hao College of Chemistry and Chemical Engineering Ministry of Education Ocean University of China Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China National Marine Hazard Mitigation Service Fujian Marine Environment and Fishery Resource Monitoring Center

Based on field data for nutrients collected on the continental shelf of the East China Sea(ECS) during summer 2006, the structure and variations of nutrients in every water mass related to the Taiwan Warm Current(TWC) were analyzed. The supplementary effect of nutrient of upwelling on harmful algal blooms(HABs) in the ECS was also estimated, based on upwelling data. Then the maintenance contribution of nutrient of upwelling to HABs was assessed. The results showed that N/P ratio is fairly low in both surface and deep layers of the TWC, which possibly controls nutrient structure of the HABs-frequently-occuring areas. In upwelling areas, the rate of phosphate(PO4-P) uptake exceeds that of nitrate(NO3-N) of the TWC. The TWC may relieve PO4-P limitation during the process of HABs. Furthermore, upwelling plays an important role in providing nutrients to HABs. After estimating nutrient fluxes(NO3-N, PO4-P, Si O3-Si) in the upwelling areas along a typical section(S07), the results showed that the nutrient uptake rate is the greatest at 10-20 m below euphotic zone, sustaining the ongoing presence of HABs. The uptake rate of PO4-P is the highest among dissolved inorganic nutrients. Therefore, upwelling is most likely the main source of PO4-P supply to HABs.

关键词：上升流区通量估算东中国海台湾暖流营养盐结构养分夏季

The Burial of Biogenic Silica, Organic Carbon and Organic Nitrogen in the Sediments of the East China Sea

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Journal of Ocean University of China 2015年第3期14卷 464-470页

作者： WANG Lisha ZHANG Chuansong shi xiaoyong College of Chemistry and Chemical Engineering Ocean University of China Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China National Marine Hazard Mitigation Service

We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic matters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the contents of these substances to be in the ranges of 0.72%-1.64%, 0.043%-0.82%, and 0.006%-0.11%, respectively. Their distributions were similar to each other, being high inside the Hangzhou Bay and low outside the bay. The vertical variations of the contents were also similar. In order to discuss the relation between them we analysed the variations of content with depth. They increased in the first 7 cm and then decreased with depth. The peaks were found at depths between 20 to 25 cm. The distribution of carbonate showed an opposite trend to that of biogenic matters. The content of total carbon was relatively stable with respect to depth, and the ratio of high organic carbon to carbonate showed a low burial efficiency of carbonate, which means that the main burial of carbon is organic carbon. In order to discuss the source of organic matters, the ratio of organic carbon to organic nitrogen was calculated, which was 8.01 to 9.65, indicating that the organic matter in the sediments was derived mainly from phytoplankton in the seawater.

关键词：东中国海有机碳生物硅沉积物有机氮碳酸盐岩表面分布垂直变化

An estimation of nutrient fluxes to the East China Sea continental shelf from the Taiwan Strait and Kuroshio subsurface waters in summer

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Acta Oceanologica Sinica 2014年第11期33卷 1-10页

作者： LI Hongmei shi xiaoyong WANG Hao HAN Xiurong College of Chemistry and Chemical Engineering Ocean University of China National Marine Hazard Mitigation Service Fujian Marine Environment and Fishery Resource Monitoring Center

According to historical mean ocean current data through the field observations of the Taiwan Ocean Research Institute during 1991–2005 and survey data of nutrients on the continental shelf of the East China Sea（ECS） in the summer of 2006, nutrient fluxes from the Taiwan Strait and Kuroshio subsurface waters are estimated using a grid interpolation method, which both are the sources of the Taiwan Warm Current. The nutrient fluxes of the two water masses are also compared. The results show that phosphate（PO4-P）, silicate（SiO3-Si） and nitrate（NO3-N） fluxes to the ECS continental shelf from the Kuroshio upwelling water are slightly higher than those from the Taiwan Strait water in the summer of 2006. In contrast, owing to its lower velocity, the nutrient flux density（i.e., nutrient fluxes divided by the area of the specific section） of the Kuroshio subsurface water is lower than that of the Taiwan Strait water. In addition, the Taiwan Warm Current deep water, which is mainly constituted by the Kuroshio subsurface water, might directly reach the areas of high-frequency harmful alga blooms in the ECS.

关键词： nutrient,flux,Taiwan Warm Current,summer,East China Sea

Investigation of seasonal variability of CDOM fluorescence in the southern Changjiang River Estuary by EEM-PARAFAC

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Acta Oceanologica Sinica 2015年第10期34卷 1-12页

作者： BAI Ying SU Rongguo HAN Xiurong ZHANG Chuansong shi xiaoyong Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education Ocean University of China

The southern Changjiang River Estuary has attracted considerable attention from marine scientists because it is a highly biologically active area and is biogeochemically significant. Moreover, land-ocean interactions strongly impact the estuary, and harmful algal blooms （HABs） frequently occur in the area. In October 2010 and May 2011, water samples of chromophoric dissolved organic matter （CDOM） were collected from the southern Changjiang River Estuary. Parallel factor analysis （PARAFAC） was used to assess the samples＇ CDOM composition using excitation-emission matrix （EEM） spectroscopy. Four components were identified： three were humic-like （C1, C2 and C3） and one was protein-like （C4）. Analysis based on spatial and seasonal distributions, as well as relationships with salinity, Chl a and apparent oxygen utilization （AOU）, revealed that terrestrial inputs had the most significant effect on the three humic-like Components C1, C2 and C3 in autumn. In spring, microbial processes and phytoplankton blooms were also important factors that impacted the three components. The protein-like Component C4 had autochthonous and allochthonous origins and likely represented a biologically labile component. CDOM in the southern Changjiang River Estuary was mostly affected by terrestrial inputs. Microbial processes and phytoplankton blooms were also important sources of CDOM, especially in spring. The fluorescence intensities of the four components were significantly higher in spring than in autumn. On average, C1, C2, C3, C4 and the total fluorescence intensity （TFI） in the surface, middle and bottom layers increased by 123%-242%, 105%-195%, 167%-665%, 483%-567% and 184%-245% in spring than in autumn, respectively. This finding corresponded with a Chl a concentration that was 16-20 times higher in spring than in autumn and an AOU that was two to four times lower in spring than in autumn. The humification index （HIX） was lower in spring that in autumn, and the fluorescence index （FI） was higher in spring than in autumn. This res

关键词： southern Changjiang River Estuary chromophoric dissolved organic matter fluorescence excitationemission matrix spectroscopy parallel factor analysis humification index fluorescence index

Assessing the dynamics of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn by EEMs-PARAFAC

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Science China Chemistry 2012年第12期55卷 2595-2609页

作者： YAN LiHong SU RongGuo ZHANG ChuanSong shi xiaoyong ZHU ChenJian Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationOcean University of ChinaQingdao 266100China

In this study we have successfully characterized the fluorescent components of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn using excitation-emission matrix fluorescence spectroscopy(EEMs) combined with parallel factor analysis(PARAFAC).PARAFAC aids the characterization of fluorescence CDOM by decomposing the fluorescence matrices into individual components.Four humic-like components(C1,C2,C3,and C4),one marine biological production component(C6),and two protein-like components(C5 and C7) were identified by PARAFAC.We researched the distributional patterns of fluorescence intensity,regression analyses between salinity,chlorophyll a concentration and fluorescence intensities of individual fluorophore,and regression analysis between salinity and fluorescence intensities percent of individual fluorophore.The results revealed that C2 and C4 showed conservative mixing behavior,while C1 and C3 possessed conservative mixing behavior in high salinity region and additional behavior in low and middle salinity region,which were considered to be derived from riverine and degradation of organic matter from resuspended and/or sinking particles and show non-conservative mixing behavior.In addition to riverine sources,the tryptophan-like C5 may receive widespread addition(likely from photo-degradation or biodegradation),while the most likely sources for the one marine humic-like C6 and tyrosine-like C7 were biological activity and microbial processing of plankton-derived CDOM,which were suggested to be of autochthonous origin and biologically labile.The application of EEM-PARAFAC modeling presents a unique opportunity to observe compositional changes,different mixing behavior and temporal variability in CDOM in the Yellow Sea and the East China Sea.

关键词：有色可溶性有机物东中国海动态评估黄海荧光物质叶绿素a浓度矩阵分解生物生产

Discrimination of marine algal taxonomic groups based on fluorescence excitation emission matrix, parallel factor analysis and CHEMTAX

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Acta Oceanologica Sinica 2014年第12期33卷 192-205页

作者： CHEN Xiaona SU Rongguo BAI Ying shi xiaoyong YANG Rujun College of Chemistry and Chemical Engineering Ocean University of China

An in vivo three-dimensional fluorescence method for the determination of algae community structure was developed by parallel factor analysis （PARAFAC） and CHEMTAX. The PARAFAC model was applied to fluo-rescence excitation-emission matrix （EEM） of 60 algae species belonging to five divisions and 11 fluorescent components were identified according to the residual sum of squares and specificity of the composition profiles of fluorescent. By the 11 fluorescent components, the algae species at different growth stages were classified correctly at the division level using Bayesian discriminant analysis （BDA）. Then the reference fluo-rescent component ratio matrix was constructed for CHEMTAX, and the EEM-PARAFAC-CHEMTAX method was developed to differentiate algae taxonomic groups. The correct discrimination ratios （CDRs） when the fluorometric method was used for single-species samples were 100% at the division level, except for Bacil-lariophyta with a CDR of 95.6%. The CDRs for the mixtures were above 94.0% for the dominant algae species and above 87.0% for the subdominant algae species. However, the CDRs of the subdominant algae species were too low to be unreliable when the relative abundance estimated was less than 15.0%. The fluorometric method was tested using the samples from the Jiaozhou Bay and the mesocosm experiments in the Xiaomai Island Bay in August 2007. The discrimination results of the dominant algae groups agreed with microscopy cell counts, as well as the subdominant algae groups of which the estimated relative abundance was above 15.0%. This technique would be of great aid when low-cost and rapid analysis is needed for samples in a large batch. The fluorometric technique has the ability to correctly identify dominant species with proper abundance both in vivo and in situ.

关键词： CHEMTAX fluorescence excitatiqn-emission matrices in vivo fluorescent components,parallel factor analysis phytoplankton

基于GaN的开关线性复合高速随动脉冲负载直流变换器

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电工技术学报 2024年第6期39卷 1818-1829页

作者：樊靖轩施佳楠徐子梁任小永陈乾宏南京航空航天大学江苏省新能源发电与电能变换重点实验室南京210016

有源相控阵雷达发射机收发组件工作在高频脉冲负载模式,这对其供电电源的负载动态性能提出了很高要求。该文针对高速负载切换的二次DC-DC电源,提出开关线性复合并联结构的脉冲负载变换器及其相应的控制策略。基于器件级环路建模的方法... 详细信息

有源相控阵雷达发射机收发组件工作在高频脉冲负载模式,这对其供电电源的负载动态性能提出了很高要求。该文针对高速负载切换的二次DC-DC电源,提出开关线性复合并联结构的脉冲负载变换器及其相应的控制策略。基于器件级环路建模的方法有效提升了线性稳压电路的环路带宽,使其进行快速功率跟踪,并设计基于GaN的低阻抗交错并联Buck变换器,使其以较快的速度高效地提供主要脉冲功率。针对重复频率50 kHz、峰值功率120 W的高频模拟雷达脉冲负载,该文搭建脉冲电流上升下降时间50 ns以内的脉冲电源原理样机,输出电压跌落小于5%。实验结果表明所提方法能够有效改善脉冲电源的动态性能。

关键词：脉冲电源相控阵雷达氮化镓动态响应

抽蓄进水球阀工作及检修密封的活动环密封设计选型

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水电站机电技术 2024年第5期47卷 75-77页

作者：施肖永杭州凯门机电设备有限公司浙江杭州310016

随着我国“十四五”规划和“碳达峰、碳中和”等战略目标的推进,风电、光伏等可再生能源得到了飞跃式发展,风能与太阳能为间歇性能源,发电量不稳定,需要储能设备来平稳电网,故大型储能设备—抽水蓄能电站,得以爆发式增长。承担抽水蓄能... 详细信息

随着我国“十四五”规划和“碳达峰、碳中和”等战略目标的推进,风电、光伏等可再生能源得到了飞跃式发展,风能与太阳能为间歇性能源,发电量不稳定,需要储能设备来平稳电网,故大型储能设备—抽水蓄能电站,得以爆发式增长。承担抽水蓄能电站安全保护措施的进水球阀,也备受市场的关注,进水球阀中的工作密封和检修密封上的活动环密封,是最易出现问题的部件,本文着重介绍了活动环密封在运行中出现的问题,以及相应的预防措施及改进方案,为进水球阀设计及制造等相关技术人员提供参考和借鉴。

关键词：活动环密封计算选型试验