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Secondary decay effects of the isospin fractionation in the projectile fragmentation at GeV/nucleon

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Nuclear Science and Techniques 2020年第12期31卷 122-128页

作者： chen-chen guo Jun Su Long Zhu Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China

The isospin fractionations in 124Sn,107Sn+120Sn at 600 MeV/nucleon,and 136Xe,124Xe+208Pb at 1000 MeV/nucleon are investigated by the isospin-dependent quantum molecular dynamics model coupled with the statistical code *** yield ratio as a function of the binding energy difference for light mirror nuclei 3H/3He,7Li/7Be,11B/11C,and 15N/15O is applied to estimate the ratio between neutrons and protons in the gas of the fragmenting *** comparing the estimated values resulting from the simulations with and without the GEMINI code,it was found that the secondary decay distorts the signal of the isospin *** minimize the secondary decay effects,the yield ratio of the light mirror nuclei 3H/3He as well as its double ratio between two systems with different isospin asymmetries of the projectiles is recommended as robust isospin observables.

关键词： Quantum molecular dynamics model(QMD) Isospin fractionation Secondary decay effect

Duality theorem for L-R crossed coproducts

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Applied Mathematics(A Journal of Chinese Universities) 2018年第3期33卷 359-378页

作者： chen Quan-guo WANG Ding-guo School of Mathematical Sciences Qufu Normal University

In this paper, the notion of L-R crossed coproduct is introduced as a unified approach for smash coproducts, crossed coproducts and L-R smash coproducts of Hopf algebras.A duality theorem for L-R crossed coproduct is ... 详细信息

关键词： Hopf algebra crossed coproduct cleft coextension

Modal analysis strategy and nonlinear dynamic characteristics of complicated aero-engine dual-rotor system with rub-impact

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Chinese Journal of Aeronautics 2022年第1期35卷 184-203页

作者： Pingchao YU guo chen Lunxu LI College of Civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 211106China

This paper aims to gain insight into the nonlinear modal characteristics and the possible influence of the modes on the responses for the practical dual-rotor system with rub-impact in *** finite solid element method combined with a constraint stiffness model produced by rub-impact is introduced to build the governing equation of the complicated nonlinear dual-rotor *** order to deal with the efficiency and numerical divergence in the process of solving the nonlinear modes of this large-scale nonlinear system,an analysis strategy is proposed by integrating a two-layer reduction technique into the harmonic balance *** effectiveness of the analysis strategy is validated by applying to a simple rotor system,which can easily obtain the theoretical *** on the modeling method and analysis strategy,the modal characteristics of an aero-engine dual-rotor system with rub-impact are *** results show that the modal frequency of the dual-rotor system increases when rub-impact occurs and has the feature of interval,which allows us to obtain the critical speeds of the rubbing system by traditional Campbell *** rotation direction is an important factor since it can not only affect the gyroscopic effect but also change the friction effect of the *** is found that the modal frequencies of the counter-rotation dual-rotor are less than those of co-rotation *** importantly,the forward modes of the counter-rotation dual-rotor may be instable when rub-impact occurs at a certain rotor,while the corresponding modes under the co-rotation condition are always ***,by analyzing the rubbing response of the dual-rotor,it is found that the modal characteristics have an important influence on rotor’s *** instable forward modes existing in the counter-rotation dual-rotor may lead to the divergence of the response when passing the corresponding critical speed.

关键词： Dual-rotor system Instability Modal characteristics Rub-impact Vibration response

RESERVOIR SEDIMENTATION AND TRANSFORMATION OF MORPHO-LOGY IN THE LOWER YELLOW RIVER DURING 10 YEAR'S INITIAL OPERATION OF THE XIAOLANGDI RESERVOIR

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Journal of Hydrodynamics 2012年第6期24卷 914-924页

作者： chen Jian-guo ZHOU Wen-hao chen Qiang International Research and Training Center on Erosion and Sedimentation(IRTCRS) China Institute of Water Resources and Hydropower Research(IWHR)

The Xiaolangdi Hydro-Project is one of the large projects on the main stem of the Middle Yellow River. It has been operated for more than 10 years, since its impoundment in October, 1999. The reservoir has trapped 2.833 × 10^9 m3 of sediment, and caused the total erosion of 1.891 × 10^9t in the Lower Yellow River from October, 1999 through October, 2010. Not only the serious atrophied situation of the Lower Yellow River （LYR） has been resuscitating, but also many new phenomena of sediment transport and behaviors of channel re-establishing are coming into being. They are illustrated and discussed in detail in this paper.

关键词： reservoir sedimentation density current water-sediment regulation artificial flood channel siltation and erosion,erosion efficiency river configuration

The Fermat-Torricelli problem on surfaces

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Applied Mathematics(A Journal of Chinese Universities) 2016年第3期31卷 362-366页

作者： chen Zhi-guo Department of Mathematics Zhejiang University

In this note a simple proof of the famous Fermat-Torricelli problem is given. For the vertices of a given triangle, Fermat asks for a fourth point such that the sum of its Euclidean distances to the three given points is minimized. Many authors present geometric approaches to the Fermat-Torricelli problem. We solve the problem by analytic and geometrical method and extend it to the sphere, we also characterize the median point P on the general regular surface.

关键词： Fermat-Torricelli problem median point geodesic distance regular surface

openGauss: An Enterprise-Grade Open-Source Database System

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JOURNAL OF COMPUTER SCIENCE AND TECHNOLOGY 2024年第5期39卷 1007-1028页

作者： Li, guo-Liang Wang, Jiang chen, guo Tsinghua Univ Dept Comp Sci Beijing 100084 Peoples R China Huawei Technol Co Ltd Beijing 100088 Peoples R China China Mobile Informat Technol Ctr Beijing 100027 Peoples R China

We have built openGauss, an enterprise-grade open-source database system. openGauss has fulfilled its design goal of high performance, high availability, high security, and high intelligence. For high performance, it leverages NUMA (non-uniform memory access)-aware data access among multiple cores to enable efficient concurrent transaction processing, and symmetric multi-processing to make use of parallel processing resources adaptively. Moreover, memory-optimized tables (MOTs) are designed to put everything in memory. For high availability, a three-tier pooling architecture that shares storage among the master and standby instances is proposed to achieve availability at 99.99%, containing both a distributed memory service (DMS) and a distributed storage service (DSS). For high security, it is a fully encrypted database with safe storage features, efficient complex querying, and tamper-proof. For high intelligence, an AI-based optimizer in the kernel and a self-driving platform named DBMind are demonstrated to achieve better performance and greater user-friendliness. openGauss has served over 150 enterprises and institutions since its release in 2020. We share the lessons we learned from its development and operation, and our customers.

关键词： database system open-source high performance storage engine

A Stochastic Approach of Dependency Evaluation for IoT Devices

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Chinese Journal of Electronics 2016年第2期25卷 209-214页

作者： HUANG Jiwei chen guo chenG Bo State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications

Internet of things(Io T) is an emerging technique that offers advanced connectivity of devices, systems, services, and human beings. With the rapid development of hardware and network technologies, the Io T can refer to a wide variety and large number of devices, resulting in complex relationships among Io T devices. The dependencies among Io T devices, which reflect their relationships, are with reference value for the design, development and management of Io T devices. This paper proposes a stochastic model based approach for evaluating the dependencies of Io T devices. A random walk model is proposed to describe the relationships of Io T devices, and its corresponding Markov chain is obtained for dependency analysis. A framework as well as schemes and algorithms for dependency evaluation in real-world Io T are designed based on traffic measurement. Simulation experiments based on real-life data extracted from smart home environments are conducted to illustrate the efficacy of the approach.

关键词： Internet of things(IoT) Dependency Random walk Markov chain

A new type of the generalized Bézier curves

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Applied Mathematics(A Journal of Chinese Universities) 2011年第1期26卷 47-56页

作者： chen Jie WANG guo-jin Department of Mathematics Zhejiang University Hangzhou 310027 China

In this paper, we improve the generalized Bernstein basis functions introduced by Han, et al. The new basis functions not only inherit the most properties of the classical Bernstein basis functions, but also reserve the shape parameters that are similar to the shape parameters of the generalized Bernstein basis functions. The degree elevation algorithm and the conversion formulae between the new basis functions and the classical Bernstein basis functions are obtained. Also the new Q-Bezier curve and surface constructed by the new basis functions are given and their properties are discussed.

关键词： Shape parameter shape control degree elevation.

Axial enantiomers with donor-regulated TADF feature for multicolor circularly polarized electroluminescence

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Science China Chemistry 2024年第6期67卷 2039-2045页

作者： chen-Hao guo Wen-Long Zhao Ke-Ke Tan Wei-chen guo Liheng Feng Chuan-Feng chen Meng Li School of Chemistry and Chemical Engineering Shanxi UniversityTaiyuan030006China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

This study optimized the TADF feature of axial chiral enantiomers through precise donor engineering,and multicolor CP-TADFwas achieved in the axial chiral *** pairs of axial enantiomers with donor-regulated TADF feature,namely(R/S)-TPCBD,(R/S)-DPCBD,and(R/S)-DPACBD,were synthesized by introducing carbazole donors with different substituents onto biphenyl cyanide *** the electron-donating ability of donors increases,the emission of these axial enantiomers ranges from 455,476 to 552 nm,their singlet-triplet energy gaps(ΔE_(ST))gradually decrease from 0.30,0.22 to 0.02 e V,accompanied by an increasement in the transition rate(k_(RISC))of RISC process,and the k_(RISC)of DPACBD could reach up to 7.16×10^(5)s^(-1).These axial enantiomers also exhibit mirror-image CD and circularly polarized luminescence(CPL)***,OLEDs based on TPCBD,DPCBD,and DPACBD as emitter were then fabricated,which displayed blue,green,and orange electroluminescence with EQE_(max)of 13.0%,16.4%,and 25.0%,*** results also exhibited a phenomenon of device efficiency increasing with the enhancement of donor ***,the CP-OLEDs using(R/S)-TPCBD,(R/S)-DPCBD and(R/S)-DPACBD as emitters displayed intense CPEL signals with g_(EL)values of 3.4×10^(-3)/-4.1×10^(-3),3.2×10^(-3)/-3.1×10^(-3)and2.3×10^(-3)/-2.1×10^(-3),*** convenient molecular engineering of donor regulation in the same molecular skeleton,CP-TADF materials with multicolor CPEL and improved device performance could be conveniently achieved.

关键词： axial chirality thermally activated delayed fluorescence circularly polarized luminescence electroluminescence organic light-emitting diodes