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Risk assessment of oil and gas investment environment in countries along the Belt and Road Initiative

Petroleum Science 2024年第2期21卷 1429-1443页

作者： Bao-Jun Tang Chang-jing ji Yu-xian Zheng Kang-Ning Liu Yi-fei Ma Jun-Yu Chen Center for Energy and Environmental Policy Research Beijing Institute of TechnologyBeijing100081China School of Management and Economics Beijing Institute of TechnologyBeijing100081China Collaborative Innovation Center of Electric Vehicles in Beijing BeijingChina Sustainable Development Research Institute for Economy and Society of Beijing BeijingChina Institute of Carbon Neutrality ShanghaiTech UniversityShanghai201210China

With the implementation of the Belt and Road Initiative, China is deepening its cooperation in oil and gas resources with countries along the Initiative. In order to better mitigate risks and enhance the safety of investments, it is of significant importance to research the oil and gas investment environment in these countries for China's overseas investment macro-layout. This paper proposes an indicator system including 27 indicators from 6 dimensions. On this basis, game theory models combined with global entropy method and analytic hierarchy process are applied to determine the combined weights, and the TOPSIS-GRA model is utilized to assess the risks of oil and gas investment in 76 countries along the Initiative from 2014 to 2021. Finally, the GM(1,1) model is employed to predict risk values for 2022-2025. In conclusion, oil and gas resources and political factors have the greatest impact on investment environment risk, and 12 countries with greater investment potential are selected through cluster analysis in conjunction with the predicted results. The research findings may provide scientific decisionmaking recommendations for the Chinese government and oil enterprises to strengthen oil and gas investment cooperation with countries along the Belt and Road Initiative.

关键词： Belt and Road Initiative Oil and Gas Investment Risk assessment

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Basic Survey Scheduling for the Wide Field Survey Telescope(WFST)

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Research in Astronomy and Astrophysics 2024年第1期24卷 59-69页

作者： Yan-Peng Chen ji-An jiang Wen-Tao Luo xian-Zhong Zheng Min Fang Chao Yang Yuan-Yu Hong Zong-fei Lü Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Department of Astronomy University of Science and Technology of ChinaHefei 230026China National Astronomical Observatory of Japan National Institutes of Natural Sciences2-21-1 OsawaMitakaTokyo 181-8588Japan Institute of Deep Space Sciences Deep Space Exploration LaboratoryHefei 230026China

Aiming at improving the survey efficiency of the Wide Field Survey Telescope, we have developed a basic scheduling strategy that takes into account the telescope characteristics, observing conditions, and weather conditions at the Lenghu site. The sky area is divided into rectangular regions, referred to as “tiles,” with a size of2°. 577 × 2°. 634 slightly smaller than the focal area of the mosaic CCDs. These tiles are continuously filled in annulars parallel to the equator. The brightness of the sky background, which varies with the moon phase and distance from the moon, plays a significant role in determining the accessible survey fields. Approximately 50connected tiles are grouped into one block for observation. To optimize the survey schedule, we perform simulations by taking into account the length of exposures, data readout, telescope slewing, and all relevant observing conditions. We utilize the Greedy Algorithm for scheduling optimization. Additionally, we propose a dedicated dithering pattern to cover the gaps between CCDs and the four corners of the mosaic CCD array, which are located outside of the 3° field of view. This dithering pattern helps to achieve relatively uniform exposure maps for the final survey outputs.

关键词： telescopes surveys Moon

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Catalytically generated noncovalent ammonium dienolate:a versatile platform for the development of organocatalytic asymmetric cascade reactions

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Science China Chemistry 2024年第8期67卷 2524-2546页

作者： Jun-Bing Lin Dong-Sheng ji Peng-fei Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China Shaanxi Key Laboratory of Chemical Reaction Engineering College of Chemistry and Chemical EngineeringYan’an UniversityYan’an 716000China

Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structural feature and diverse reactivity of catalytically generated dienolate species render them competent and versatile intermediates for the development of practical and valuable cascade reactions. Over the past years, a plethora of innovative and pioneering noncovalent ammonium dienolatemediated cascade reactions have been designed and implemented under the catalysis of chiral organocatalysts, making dienolate activation a general, robust, and complementary method for the functionalization of unsaturated carbonyl compounds and related substances. This review illustrates the recent advances in organocatalytic noncovalent ammonium dienolate-mediated cascade reactions(mainly from 2010 to 2023), including the cascade transformations of ammonium dienolates directly generated from unsaturated ketone/aldehyde, ester/lactone/azlactone, amide/lactam/pyrazolone/oxindole, and alkylidene nitrile compounds. The contents are arranged based on the reaction types of the ammonium dienolates, with an emphasis on cascade 2,5-, 3,5-, and 4,5-difunctionalizations of these intermediates. Furthermore, other cascade reactions involving the 1,3-, 2,3-, and even more complex 3,4,5-reactivities of ammonium dienolates were also discussed. The reaction pathway, reaction stereoinduction, and synthetic applications of the ammonium dienolate-mediated cascade reactions were highlighted throughout the article. As a stimulating and ever-growing research area, the organocatalytic noncovalent ammonium dienolate-mediated cascade reactions are expected to continue demonstrating their magic power for constructing chiral targets in the future and further expanding the boundaries of asymmetric catalysis.

关键词： organocatalysis asymmetric catalysis ammonium dienolate cascade reaction difunctionalization

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Nuclearity and Finite-Representability in the System of Completely Integral Mapping Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1197-1214页

作者： Zhe DONG ji Cheng TAO Ya fei ZHAO Department of Mathematics Zhejiang UniversityHangzhou 310027P.R.China Department of Mathematics China Jiliang UniversityHangzhou 310018P.R.China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310023P.R.China

In this paper,we investigate local properties in the system of completely integral mapping *** introduce notions of injectivity,local reflexivity,exactness,nuclearity,finite-represent ability and WEP in the system of completely integral mapping *** we obtain that any finite-dimensional operator space is injective in the system of completely integral mapping *** we prove that C is the unique nuclear operator space and the unique exact operator space in this *** also show that C is the unique operator space which is finitely representable in{T_(n)}n∈Nin this *** corollaries,Kirchberg’s conjecture and QWEP conjecture in the system of completely integral mapping spaces are false.

关键词： Completely integral mapping space injectivity exactness nuclearity finite-representability WEP

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Asymmetric Drying and Wetting Trends in Eastern and Western China

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Advances in Atmospheric Sciences 2024年第2期41卷 221-232页

作者： Wen WU fei ji Shujuan HU Yongli HE College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China Collaborative Innovation Center for Western Ecological Safety Lanzhou UniversityLanzhou 730000China

As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.

关键词： aridity index EEMD dry/wet conditions asymmetric evolution

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Intelligent responsive self-assembled micro-nanocapsules: Used to delay gel gelation time

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Petroleum Science 2024年第4期21卷 2433-2443页

作者： Chuan-Hong Kang ji-xiang Guo Dong-Tao fei Wyclif Kiyingi Unconventional Petroleum Research Institute China University of Petroleum

In the application of polymer gels to profile control and water shutoff,the gelation time will directly determine whether the gel can "go further" in the formation,but the most of the methods for delaying gel gelation time are complicated or have low *** is an urgent need for an effective method for delaying gel gelation time with intelligent *** by the slow-release effect of drug capsules,this paper uses the self-assembly effect of gas-phase hydrophobic SiO2in aqueous solution as a capsule to prepare an intelligent responsive self-assembled *** capsule slowly releases the cross-linking agent under the stimulation of external conditions such as temperature and pH value,thus delaying gel gelation *** the pH value is 2 and the concentration of gas-phase hydrophobic SiO2particles is 10%,the gelation time of the capsule gel system at 30,60,90,and 120℃ is12.5,13.2,15.2,and 21.1 times longer than that of the gel system without containing capsule,*** with other methods,the yield stress of the gel without containing capsules was 78 Pa,and the yield stress after the addition of capsules was 322 *** intelligent responsive self-assembled micronanocapsules prepared by gas-phase hydrophobic silica nanoparticles can not only delay the gel gelation time,but also increase the gel *** slow release of cross-linking agent from capsule provides an effective method for prolongating the gelation time of polymer gels.

关键词： Profile control and water shutoff Polymer gel Delayed gelation time Intelligent response Self-assembled Micro-nanocapsules

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Joint computation offloading and parallel scheduling to maximize delay-guarantee in cooperative MEC systems

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Digital Communications and Networks 2024年第3期10卷 693-705页

作者： Mian Guo Mithun Mukherjee Jaime Lloret Lei Li Quansheng Guan fei ji School of Electronics and Information Guangdong Polytechnic Normal UniversityGuangzhouChina School of Artificial Intelligence Nanjing University of Information Science and TechnologyNanjingChina Universitat Politecnica de Valencia 46022ValenciaSpain South China University of Technology China

The growing development of the Internet of Things(IoT)is accelerating the emergence and growth of new IoT services and applications,which will result in massive amounts of data being generated,transmitted and pro-cessed in wireless communication *** Edge Computing(MEC)is a desired paradigm to timely process the data from IoT for value *** MEC,a number of computing-capable devices are deployed at the network edge near data sources to support edge computing,such that the long network transmission delay in cloud computing paradigm could be *** an edge device might not always have sufficient resources to process the massive amount of data,computation offloading is significantly important considering the coop-eration among edge ***,the dynamic traffic characteristics and heterogeneous computing capa-bilities of edge devices challenge the *** addition,different scheduling schemes might provide different computation delays to the offloaded ***,offloading in mobile nodes and scheduling in the MEC server are coupled to determine service *** paper seeks to guarantee low delay for computation intensive applica-tions by jointly optimizing the offloading and scheduling in such an MEC *** propose a Delay-Greedy Computation Offloading(DGCO)algorithm to make offloading decisions for new tasks in distributed computing-enabled mobile devices.A Reinforcement Learning-based Parallel Scheduling(RLPS)algorithm is further designed to schedule offloaded tasks in the multi-core MEC *** an offloading delay broadcast mechanism,the DGCO and RLPS cooperate to achieve the goal of delay-guarantee-ratio ***,the simulation results show that our proposal can bound the end-to-end delay of various *** under slightly heavy task load,the delay-guarantee-ratio given by DGCO-RLPS can still approximate 95%,while that given by benchmarked algorithms is reduced to intolerable *** simulation resul

关键词： Edge computing Computation offloading Parallel scheduling Mobile-edge cooperation Delay guarantee

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Numerical simulation of liquid sloshing in a spherical tank by MPS method

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Journal of Hydrodynamics 2024年第2期36卷 232-240页

作者： Cong-yi Huang ji-fei Wang Wei-wen Zhao De-cheng Wan Computational Marine Hydrodynamic Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Aerospace System Engineering Institute Shanghai201109China

This paper investigates the sloshing phenomena in a spherical liquid tank using the moving particle semi-implicit(MPS)method,a crucial study in fluid *** from previous research focused on rectangular or LNG tanks,this work explores the unique motion patterns inherent to spherical *** accuracy of our in-house MPS solver MLParticle-SJTU is validated against experimental data and finite volume method(FVM).And the MPS method reveals a closer alignment with experimental outcomes,which suggests that MPS method is particularly effective for modeling complex,non-linear fluid *** the fluid’s response to excitation at its natural frequency is simulated,showcasing vigorous sloshing and rotational *** analyses of the fluid motion are conducted by drawing streamline diagrams,velocity vector diagrams,and vorticity *** fluid’s motion response is explored using both time-domain and frequency-domain curves of the fluid centroid,as well as the sloshing force.

关键词： Moving particle semi-implicit(MPS)method spherical tank liquid sloshing model experiment

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A Pre-Selection-Based Ant Colony System for Integrated Resources Scheduling Problem at Marine Container Terminal

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Computers, Materials & Continua 2024年第8期80卷 2363-2385页

作者： Rong Wang Xinxin Xu Zijia Wang fei ji Nankun Mu School of Electronic and Information Engineering South China University of TechnologyGuangzhou510641China School of Computer Science and Technology Ocean University of ChinaQingdao266100China School of Computer Science and Cyber Engineering Guangzhou UniversityGuangzhou510006China School of Computer Science Chongqing UniversityChongqing400044China

Marine container terminal(MCT)plays a key role in the marine intelligent transportation system and international logistics ***,the efficiency of resource scheduling significantly influences the operation performance of *** solve the practical resource scheduling problem(RSP)in MCT efficiently,this paper has contributions to both the problem model and the algorithm ***,in the problem model,different from most of the existing studies that only consider scheduling part of the resources in MCT,we propose a unified mathematical model for formulating an integrated *** new integrated RSP model allocates and schedules multiple MCT resources simultaneously by taking the total cost minimization as the ***,in the algorithm design,a pre-selection-based ant colony system(PACS)approach is proposed based on graphic structure solution representation and a pre-selection *** the one hand,as the RSP can be formulated as the shortest path problem on the directed complete graph,the graphic structure is proposed to represent the solution encoding to consider multiple constraints and multiple factors of the RSP,which effectively avoids the generation of infeasible *** the other hand,the pre-selection strategy aims to reduce the computational burden of PACS and to fast obtain a higher-quality *** evaluate the performance of the proposed novel PACS in solving the new integrated RSP model,a set of test cases with different sizes is *** results and comparisons show the effectiveness and efficiency of the PACS algorithm,which can significantly outperform other state-of-the-art algorithms.

关键词： Resource scheduling problem(RSP) ant colony system(ACS) marine container terminal(MCT) pre-selection strategy

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Three-dimensionally oriented organization of hexagonal MIL-96 microplates toward superior film microstructure

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Chinese Journal of Chemical Engineering 2024年第8期72卷 69-73页

作者： Sixing Chen Xinmiao jin Yuyang Wu Taotao ji fei Wang Yi Liu State Key Laboratory of Fine Chemicals Frontiers Science Center for Smart MaterialsSchool of Chemical EngineeringDalian University of TechnologyDalian 116024China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Dalian Key Laboratory of Membrane Materials and Membrane Processes Dalian University of TechnologyDalian 116024China

Preferential orientation control of metal—organic framework(MOF)films is advantageous for maximizing pore uniformity and minimizing grain-boundary ***,the preparation of MOF films with both in-plane and out-of-plane orientations remains a grand *** this study,we reported the preparation of three-dimensionally oriented MIL-96 layers through combining morphology control of MIL-96 seeds with addition of polyvinylpyrrolidone surfactants and arachidonic *** three-dimensionally oriented MIL-96 film was readily obtained through in-plane epitaxial *** is anticipated that the aforementioned protocol can be effective for obtaining diverse MOF films with a three-dimensionally oriented organization.

关键词： Metaleorganic framework Film Orientation Epitaxial growth Morphological control

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