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Upper Bounds for Ruin Probabilities under Stochastic Interest Rate and Optimal Investment Strategies

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Acta Mathematica Sinica,English Series 2012年第7期28卷 1421-1430页

作者： jin zhu li rong wu School of Mathematical Sciences and LPMC Nankai University

In this paper, we study the upper bounds for ruin probabilities of an insurance company which invests its wealth in a stock and a bond. We assume that the interest rate of the bond is stochastic and it is described by a Cox-Ingersoll-Ross （CIR） model. For the stock price process, we consider both the case of constant volatility （driven by an O U process） and the case of stochastic volatility （driven by a CIR model）. In each case, under certain conditions, we obtain the minimal upper bound for ruin probability as well as the corresponding optimal investment strategy by a pure probabilistic method.

关键词： Cox Ingersoll-Ross model jump-diffusion model optimal investment Ornstein Uhlen- beck (O-U) process ruin probability stochastic interest rate

The Gerber-Shiu Discounted Penalty Function for a Compound Binomial Risk Model with By-claims

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Acta Mathematicae Applicatae Sinica 2015年第1期31卷 181-190页

作者： jin-zhu li rong wu School of Mathematical Sciences and LPMC Nankai University

A recursive formula of the Gerber-Shiu discounted penalty function for a compound binomial risk model with by-claims is obtained. In the discount-free case, an explicit formula is given. Utilizing such an explicit expression, we derive some useful insurance quantities, including the ruin probability, the density of the deficit at ruin, the joint density of the surplus immediately before ruin and the deficit at ruin, and the density of the claim causing ruin.

关键词： compound binomial risk model Gerber-Shiu function by-claims

Recent progress on photoactive nonprecious transition-metal complexes

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Science China Chemistry 2025年第1期 46-95页

作者： Zhong-liang Gong Hong-Jie Zhang Yan Cheng Jianxun liu Yuhan Ai Yaqin li Zhihui Feng Qiong Zhang Shaolong Gong Yong Chen Chang-Jiang Yao Yuan-Yuan zhu liang-jin Xu Yu-wu Zhong CAS Key Laboratory of Photochemistry Institute of Chemistry Chinese Academy of Sciences State Key Laboratory of Structural Cemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences School of Chemistry and Chemical Engineering Anhui Key Laboratory of Advanced Catalytic Materials and Reaction EngineeringHefei University of Technology State Key Laboratory of Explosion Science and Safety Protection School of Mechatronical Engineering Beijing Institute of Technology College of Chemistry and Molecular Sciences Hubei Key Lab on Organic and Polymeric Optoelectronic Materials Wuhan University School of Chemistry and Chemical Engineering Anhui University Key Laboratory of Photochemical Conversion and Optoelectronic Materials & CAS-HKU Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences

Photoactive complexes of nonprecious transition metals, mainly including those in the first-row and partially the second-row of the Periodic table of elements, have received increasing attention in view of their low cost and long-term sustainability. They are recognized as promising alternatives to noble transition metal complex congeners that have been extensively studied in optoelectronic devices, artificial photosynthesis, photocatalysis, biodiagnostics, and therapeutics, etc. This review is devoted to a comprehensive summary on the classical and recent advances on photoactive nonprecious transition metal complexes, including photoactive Zr, V, Cr, Mo, and W complexes, Mn complexes and hybrids, Fe, Co, Ni, and Cu complexes, and Zn and Cd complexes and hybrids. A particular focus is given on the molecular design, modulation of photophysical and photochemical properties, and applications of the representative and lately-developed nonprecious metal complexes. In addition, a perspective on the future development in this field is provided at the end of this review.

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The mechanical and water absorption properties of carbon fiber buoyancy materials under hydrostatic pressure

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Science China Technological Sciences 2025年第1期 251-265页

作者： Fanglin CONG Zihan li Guocai YU Yang jin Zixu zhu linzhi wu College of Aerospace and Civil Engineering Harbin Engineering University Key Laboratory of Advanced Ship Materials and Mechanics Harbin Engineering University Department of Basic Courses Naval University of Engineering

Buoyancy material technology is of paramount importance for the development of marine engineering. In this study,a novel carbon fiber buoyancy material(CFBM) is designed and prepared by utilizing composite circular tubes with light weight and high strength. To reveal the failure mechanism under hydrostatic pressure, a finite element model(FEM) based on the three-dimensional Hashin and Yeh failure criterion is developed and validated experimentally. Both the simulated and experimental results indicate that the hydrostatic strength of the CFBM is mainly determined by the buckling of carbon fiber tubes located at the edges of the CFBM. Parametric analysis is conducted to investigate the effect of the number of unit-cells,length, and wall thickness of carbon fiber tubes on the mechanical properties of the CFBM. In addition, a 60-day water absorption test of the CFBM at 12.5 MPa is conducted to characterize its durability. Experimental results indicate that the maximum water absorption rate of the CFBM is 0.59% and the hydrostatic strength is reduced by only 7.97% during the 60-day test period. Finally, the designed CFBM is used at the water depth of 1000 m as buoyancy material. Compared with traditional buoyancy materials, the proposed CFBM has significant advantages in both hydrostatic strength and density. This work has broad engineering application prospects and is of high significance for promoting the implementation of carbon fiber composites in the ocean engineering field.

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Einstein Probe discovery of EP240408a: A peculiar X-ray transient with an intermediate timescale

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

作者： Wenda Zhang Weimin Yuan Zhixing ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati lixin Dai jingwei Hu Shumei Jia Chichuan jin Dongyue li Paul O’Brien rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong li Bifang liu Mingjun liu Xing liu Yuan liu zhu liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen wu Xuefeng wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge jin Chengkui li Junfei li Longhui li Maoshun li Wei li Zhengda li Tianying lian Congzhan liu Heyang liu Huaqiu liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu wu Haitao Xu jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan zhu Zhencai zhu National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences University of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Institute of Space Sciences (ICE) CSIC Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck Institute for Extraterrestrial Physics Innovation Academy for Microsatellites Chinese Academy of Sciences Department of Physics University of Hong Kong School of Physics and Astronomy University of Leicester School of Physics and Astronomy Sun Yat-sen University Department of Physics Anhui Normal University Shanghai Institute of Technical Physics Chinese Academy of Sciences Physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of Physics and Astronomy University of Nevada Las Vegas South African Astronomical Observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr Institute University of Copenhagen Department of Physics and Astronomy Rutgers the State University of New Jersey Institute for Cosmic Ray Research The University of Tokyo ESA/ESTEC Department of Astronomy School of Physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics The University of Sydney Department of Astronomy Xiamen University Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology School of Astronomy and Space Sciences University of Science and Technology of China Institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan University Shanghai Astronomical Observatory Chi

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 ke V,～300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

Effect of Nb and V on the continuous cooling transformation of undercooled austenite in Cr–Mo–V steel for brake discs

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International Journal of Minerals,Metallurgy and Materials 2018年第8期25卷 892-901页

作者： Dan wu Fu-ming Wang jin Cheng Chang-rong li School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Materials Science and Engineering University of Science and Technology Beijing

The increasing speed of trains necessitates the development of brake-disc materials that meet more stringent ***,Nb and V have been added to Cr–Mo–V steel to improve its thermal fatigue performance when used in brake *** this paper,the influences of Nb and V on the static continuous cooling transformation(CCT)behaviors of undercooled austenite were *** microstructures,hardness,and dislocation densities at different cooling rates and with the addition of different alloying elements were also *** results show that the transformation products of ferrite,granular bainite,lower bainite,and martensite form under different cooling *** increasing Nb and V contents,the CCT curves are shifted to the left,ferrite and bainite transformations are promoted,and the critical cooling rate of total martensite formation is *** added V mainly forms V-rich M_8C_7 precipitates and reduces the dissolved C content;therefore,the A_(c1),A_(c3),and M_s-point temperatures ***,the stability of retained austenite is also reduced;its content therefore *** with V,the effect of added Nb is weaker because of its smaller ***,the addition of Nb improves the hardness at lower cooling rates because of the precipitation of fine Nb C particles and refining of the microstructure.

关键词： brake-disc steel niobium vanadium microstructure continuous cooling transformation

S-scheme quantum dots heterojunction photocatalysts:Assembly types,mechanism insights,and design strategies

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Nano Research 2024年第12期17卷 10259-10278页

作者： jin-Tao Ru Chen-Ho Tung li-zhu wu Key Laboratory of Photochemical Conversion and Optoelectronic Materials New Cornerstone Science LaboratoryTechnical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100190China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China

Coupling quantum dots(QDs)in S-scheme(referred to as QD-S-scheme)is an efficient approach for ***,a comprehensive review of S-scheme QDs heterojunction photocatalysts is,to the best of our knowledge,***,a concise overview of the unique advantages and limitations of QDs in photocatalytic reactions,as well as the charge transfer mechanism of the S-scheme is first ***,a thorough summary and evaluation of the types and assembly strategies of QDs are presented,highlighting the pivotal role of the QD-S-scheme heterojunction interface in photocatalytic ***,the characterization methods for the charge transfer from the bulk to the interface and surface are discussed from the perspectives of the built-in electric field(BEF),steady-state and transient charge transfer processes,and photochemical *** the design principles and optimization strategies for surface modulation,interface construction,and heterojunction design are also ***,insights on the current research status,challenges,and prospects of the QD-S-scheme are presented to contribute the development of QD-S-scheme heterojunction photocatalysts.

关键词： quantum dots S-scheme heterojunction photocatalysis

Reduction characteristics of molybdenum trioxide with aluminum and silicon

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Rare Metals 2018年第7期37卷 621-624页

作者： Hang-Yu zhu rong Gao wu-Tao jin Long-wu Qiu Zheng-liang Xue State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology School of Materials and Metallurgy Wuhan University of Science and Technology

Thermodynamics for reduction of molybdenum oxides by aluminum and silicon were calculated, and the results show that reduction reaction is feasible at a certain temperature region. Compared to the presence of CaO or CaCO3, reduction products of molybdenum trioxide with aluminum and silicon at various temperatures were detected by X-ray diffraction （XRD）. Results show that molybdenum trioxide is reduced by aluminum or silicon step by step, and the intermediate product is MOO2. At 1000 ℃, molybdenum trioxide could be reduced to metal Mo by aluminum, and in the presence of CaO, metal Mo as the reduction product appears even at 800 ℃. In contrast, silicon could barely reduce molybdenum trioxide to metal Mo even at 1200℃. In the presence of CaO or CaCO3, reducibility of silicon increases significantly, and the reduction products are metal Mo and MoSi2. Altogether, CaO or CaCO3 performs two major roles in reduction process： restraining sublimation of MoO3 and decreasing the temperature of reducing MoO3 to metal Mo.

关键词： Molybdenum trioxide Reduction Aluminum Silicon Metallothermic

Distribution and Geochemical Characteristics of Fluids in Ordovician Marine Carbonate Reservoirs of the Tahe Oilfield

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Journal of Earth Science 2014年第3期25卷 486-494页

作者： Mei li Zhanghua Lou rong zhu Aimin jin Ying Ye Ocean College Zhejiang University

The Ordovician carbonate reservoirs in the Tahe Oilfield are highly heterogeneous, which have undergone multiple superimposed transformations by tectonic activities and karst processes, leading to an extremely complex fluid distribution. The geochemical characteristics of geofluids also display great disparities. Results show that the vertical distribution of oil and gas are continuous, however the oil-water interfaces in different blocks of the Tahe Ordovician Oilfield are numerous. Meteoric water infiltration is regarded as the main reason for the high oil-water interface and high water content to the north of Tahe Oilfield, especially in well blocks S78–S73. The isotopic values of deuterium-oxygen in the groundwater and carbon-oxygen from calcite veins confirm that formation water in Ordovician reservoirs of the Tahe Oilfield was a mix of meteoric water and connate water, and the proportion of meteoric water gradually increases from south to north, while connate water decreases. The Tahe Ordovician reservoirs are characterised by multiple hydrocarbon charges, and the general migrating direction is from southeast to northwest and from east to west. High production could be obtained in the northern area of the Tahe Oilfield since the oil layers are thick and oil is highly saturated. The residual water within the reservoirs is low, and heavy oil is dominant in this area. Only a small amount of pore water has been replaced by oil in the southern Tahe Oilfield, leading to low oil saturation and a high content of residual water. Crude oil is herein mainly of medium-light type. During the process of exploration in this region, acid fracturing reformation is usually required for wells to increase their output; however the yield is still low.

关键词： fluid distribution geochemical characteristics residual water Tahe Oilfield.