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Uniform Asymptotics for Finite-Time Ruin Probabilities of Risk Models with Non-Stationary Arrivals and Strongly Subexponential Claim Sizes

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Wuhan University Journal of Natural Sciences 2024年第1期29卷 21-28页

作者： XU Chenghao wang Kaiyong PENG jiangyan School of Mathematical Sciences Suzhou University of Science and TechnologySuzhou 215009JiangsuChina School of Mathematical Sciences University of Electronic Science and Technology of ChinaChengdu 611731SichuanChina

This paper considers the one-and two-dimensional risk models with a non-stationary claim-number process.Under the assumption that the claim-number process satisfies the large deviations principle,the uniform asymptotics for the finite-time ruin probability of a one-dimensional risk model are obtained for the strongly subexponential claim sizes.Further,as an application of the result of onedimensional risk model,we derive the uniform asymptotics for a kind of finite-time ruin probability in a two dimensional risk model sharing a common claim-number process which satisfies the large deviations principle.

关键词： one-dimensional risk model two-dimensional risk model large deviations principle finite-time ruin probability heavy-tailed distributions

The development of hollow multishelled structure: from the innovation of synthetic method to the discovery of new characteristics

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Science China Chemistry 2022年第1期65卷 7-19页

作者： jiangyan wang Zumin wang Dan Mao Dan wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Hollow multishelled structure(HoMS)is one of the most promising multifunctional structures.The high complexity of its structure makes the general and controllable synthesis of HoMS rather challenging.By integration of multidisciplinary knowledge,a great achievement in HoMSs has been obtained in the past decade.Especially,the developed sequential templating approach has significantly boomed the progress of HoMS in composition and structure diversity and application area.The implementation of the temporal-spatial ordering in HoMS makes it indispensable in solving the key scientific problems in energy conversion,catalysis and drug delivery areas.Further development in HoMSs with novel intricate structures will bring new understandings.In this review,we systematically introduce the development history of HoMSs,summarize the inspiration inherited from the previous research on hollow structures,and discuss the milestones in the development of HoMSs,with a focus on the sequential templating approach for HoMS fabrication,attractive temporal-spatial ordering property and dynamic smart behavior for advanced applications.We hope to reveal the inherent relationship between the precise synthesis of HoMS and its highly tunable compositional and structural characteristics,and point out its future direction to boost HoMS area further.

关键词： hollow multishelled structure sequential templating approach temporal-spatial ordering smart dynamic behavior

Progress and Perspectives of Hollow Multishelled Structures

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Chinese Journal of Chemistry 2022年第10期40卷 1190-1203页

作者： jiangyan wang Mei Yang Dan wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Hollow multishelled structure(HoMs)has drawn tremendous attention due to its abundant attractive properties and promising applications.However,for a long time,the limited synthesis method hindered the development of HoMs.The sequential templating approach developed by our group,has greatly enriched its composition and'structure diversity.The progress in HoMS synthesis promotes the discovery of its characteristics as well as widens its application area.Typicall,the recently explored temporal-spatial ordering characteristic of HoMS has shown great promise in drug delivery and cascade catalysis application areas.Here,we summarize the current development progress of HoMS in the aspects of both synthesis and application,with a focus discussion on how to shape its application performance by manipulating its composition and structure features.In addition,we discuss the current challenges and providethe future potentials holdingfor HoMs.

关键词： Hollow multishelled structure Sequential templating approach Temporal-spatial ordering Catalysis Structure-activity relationships

Decoding lithium batteries through advanced in situ characterization techniques

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International Journal of Minerals,Metallurgy and Materials 2022年第5期29卷 965-989页

作者： Mei Yang Ruyi Bi jiangyan wang Ranbo Yu Dan wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 10049China Department of Energy Storage Science and Engineering School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Given the energy demands of the electromobility market,the energy density and safety of lithium batteries(LBs)need to be improved,whereas its cost needs to be decreased.For the enhanced performance and decreased cost,more suitable electrode and electrolyte materials should be developed based on the improved understanding of the degradation mechanisms and structure–performance correlation in the LB system.Thus,various in situ characterization technologies have been developed during the past decades,providing abundant guidelines on the design of electrode and electrolyte materials.Here we first review the progress of in situ characterization of LBs and emphasize the feature of the multi-model coupling of different characterization techniques.Then,we systematically discuss how in situ characterization technologies reveal the electrochemical processes and fundamental mechanisms of different electrode systems based on representative electrode materials and electrolyte components.Finally,we discuss the current challenges,future opportunities,and possible directions to promote in situ characterization technologies for further improvement of the battery performance.

关键词： in situ characterization techniques multi-modal coupling lithium batteries electrochemical mechanism

Hollow multishelled structural TiN as multi-functional catalytic host for high-performance lithium-sulfur batteries

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Nano Research 2023年第11期16卷 12745-12752页

作者： Wei Xu Ruyi Bi Mei Yang jiangyan wang Ranbo Yu Dan wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Biopharmaceutical Preparation and Delivery Chinese Academy of SciencesBeijing 100190China

Lithium-sulfur(Li-S)battery has attracted extensive attention because of its ultrahigh theoretical energy density and low cost.However,its commercialization is seriously hampered by its short cycling life,mainly due to the shuttle of soluble lithium polysulfides(LiPSs)and poor rate capability due to sluggish reaction kinetics.Although significant efforts have been devoted to solving the problems,it is still challenging to simultaneously address all the issues.Herein,titanium nitride hollow multishelled structure(TiN HoMS)sphere is designed as a multi-functional catalytic host for sulfur cathode.TiN,with good conductivity,can effectively catalyze the redox conversion of S and LiPSs,while its surficial oxidation passivation layer can strongly anchor LiPSs.Besides,HoMS enables TiN nanoparticle subunits to expose abundant active sites for anchoring and promoting conversion of LiPSs,while the multiple shells provide physical barriers to restrict the shuttle effect.In addition,HoMS can buffer the volume expansion of sulfur and shorten the charge transport pathway.As a result,the sulfur cathode based on triple-shelled TiN HoMS exhibits an initial specific capacity of 1016 mAh·g-1 at a high sulfur loading of 2.8 mg·cm-2 and maintains 823 mAh·g-1 after 100 cycles.Moreover,it shows a four times higher specific capacity than the one without TiN host at 2 C.

关键词： lithium-sulfur batteries titanium nitride hollow multishelled structure shuttle effect rate capability

Contribution of the Chinese Meridian Project to space environment research:Highlights and perspectives

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Science China Earth Sciences 2023年第7期66卷 1423-1438页

作者： Chi wang Jiyao XU Libo LIU Xianghui XUE Qinghe ZHANG Yongqiang HAO Gang CHEN Hui LI Guozhu LI Bingxian LUO Yajun ZHU jiangyan wang State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China School of Earth and Space Sciences University Science and Technology of ChinaHefei 230026China Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China School of Earth and Space Sciences Peking UniversityBeijing 100191China Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China Key Laboratory of Science and Technology on Environmental Space Situation Awareness National Space Science CenterChinese Academy of SciencesBeijing 100190China

The Chinese Meridian Project(CMP)is devoted to establishing a comprehensive ground-based monitoring network for China’s space weather research.CMP is a major national science and technology infrastructure project with the participation of more than 10 research institutions and universities led by the National Space Science Center of the Chinese Academy of Sciences.CMP is planned to be constructed in two phases:CMP phasesⅠandⅡ.The first phase(CMP-Ⅰ)started construction in2008 and completed in 2012,after which it entered the operation stage.The 10-year observation of CMP-Ⅰhas made significant scientific discoveries and achievements in the research fields of the middle and upper atmospheric fluctuations,metal layers in the mesosphere and lower thermosphere,ionospheric disturbances and irregularities,geomagnetic disturbances,and influences of solar activity.The review summarizes the main observations and research achievements,space weather forecast modeling and methods based on CMP-Ⅰover the past 10 years,and presents a future extension perspective along with the construction of CMP-Ⅱ.

关键词： Chinese Meridian Project Ground-based observation network Space weather Solar-terrestrial physics

Efficient sequential harvesting of solar light by heterogeneous hollow shells with hierarchical pores

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National Science Review 2020年第11期7卷 1638-1646页

作者： Yanze Wei Jiawei Wan Nailiang Yang Yu Yang Yanwen Ma Songcan wang jiangyan wang Ranbo Yu Lin Gu Lianhui wang Lianzhou wang Wei Huang Dan wang State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences Department of Physical Chemistry School of Metallurgical and Ecological EngineeringUniversity of Science and Technology Beijing University of Chinese Academy of Sciences Chinese Academy of Sciences School of Materials Science and Engineering Nanjing University of Posts and Telecommunications School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology The University of Queensland Department of Materials Science andEngineering Stanford University Institute of Physics Chinese Academy of Sciences

In nature, sequential harvesting of light widely exists in the old life entity, i.e. cyanobacteria, to maximize the light absorption and enhance the photosynthesis efficiency. Inspired by nature, we propose a brand new concept of temporally-spatially sequential harvesting of light in one single particle, which has purpose-designed heterogeneous hollow multi-shelled structures (HoMSs) with porous shells composed of nanoparticle subunits. Structurally, Ho MSs consist of different band-gap materials outside-in, thus realizing the efficient harvesting of light with different wavelengths. Moreover, introducing oxygen vacancies into each nanoparticle subunit can also enhance the light absorption. With the benefit of sequential harvesting of light in Ho MSs, the quantum efficiency at wavelength of 400 nm is enhanced by six times compared with the corresponding nanoparticles. Impressively, using these aforementioned materials as photocatalysts,highly efficient photocatalytic water splitting is realized, which cannot be achieved by using the nanoparticle counterparts. This new concept of temporally-spatially sequential harvesting of solar light paves the way for solving the ever-growing energy demand.

关键词： light harvesting hollow structures multi-shelled solar energy conversion

中空多壳层结构TiN修饰隔膜对锂硫电池性能的增强

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科学通报 2024年第16期69卷 2298-2307页

作者：徐伟毕如一杨梅王江艳于然波王丹中国科学院过程工程研究所生化工程国家重点实验室北京100190 北京科技大学冶金与生态工程学院北京100083 中国科学院大学化学工程学院北京100049 生物药制备与递送重点实验室(中国科学院) 北京100190

锂硫电池(lithium-sulfur(Li-S)batteries)具有远高于锂离子电池的理论比容量.然而,硫的导电性差,充放电过程中体积变化剧烈,其放电中间产物易溶于电解液并穿过隔膜,造成穿梭效应,导致锂硫电池的实测比容量低、循环寿命短.本文设计构筑... 详细信息

锂硫电池(lithium-sulfur(Li-S)batteries)具有远高于锂离子电池的理论比容量.然而,硫的导电性差,充放电过程中体积变化剧烈,其放电中间产物易溶于电解液并穿过隔膜,造成穿梭效应,导致锂硫电池的实测比容量低、循环寿命短.本文设计构筑了中空多壳层结构氮化钛(TiNHoMS),作为锂硫电池隔膜修饰材料,有效解决了上述难题.氮化钛具有优异的导电性,能够催化硫和多硫化锂的氧化还原转化.HoMS具有多个壳层和多层内部空腔,能提供多重空间阻隔和丰富的多硫化锂吸附位点,从而有效抑制穿梭效应,并且能够缩短电子/离子传输路径.得益于此,采用三壳层TiNHoMS修饰隔膜的锂硫电池性能显著提高,远优于采用未修饰隔膜电池的性能.测试结果表明,在1 C电流下,初始比容量由642 mAh/g提高到1134 mAh/g,而且300次循环后比容量仍保持在792 mAh/g.通过一系列电化学表征分析发现,TiNHoMS提高了隔膜对电解液的浸润性,催化了硫正极的氧化还原反应,抑制了多硫化锂的穿梭效应,从而有效地提高了锂硫电池的比容量和循环稳定性.

关键词：中空多壳层结构氮化钛隔膜修饰锂硫电池穿梭效应

A novel battery scheme:Coupling nanostructured phosphorus anodes with lithium sulfide cathodes

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Nano Research 2020年第5期13卷 1383-1388页

作者： David Sichen Wu Guangmin Zhou Eryang Mao Yongming Sun Bofei Liu Li wang jiangyan wang Feifei Shi Yi Cui Department of Materials Science and Engineering Stanford UniversityStanfordCalifornia 94305USA Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China Stanford Institute for Materials and Energy Sciences SLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCalifornia 94025USA

Lithium-ion batteries are approaching their theoretical limit and can no longer keep up with the increasing demands of human society.Lithium-sulfur batteries,with a high theoretical specific energy,are promising candidates for next generation energy storage.However,the use of Li metal in Li-S batteries compromises both safety and performance,enabling dendrite formation and causing fast capacity degradation.Previous studies have probed alternative battery systems to replace the metallic Li in Li-S system,such as a Si/Li2S couple,with limited success in performance.Recently,there is a focus on red P as a favorable anode material to host Li.Here,we establish a novel battery scheme by utilizing a P/C nanocomposite anode and pairing it with a Li2S coated carbon nanofiber cathode.We find that red P anode can be compatible in ether-based electrolyte systems and can be successfully coupled to a Li2S cathode.Our proof of concept full-cell displays remarkable specific capacity,rate and cycling performances.We expect our work will provide a useful alternative system and valuable insight in the quest for next generation energy storage devices.

关键词： lithium sulfur batteries red phosphorus lithium sulfide