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基于二次分解和集成学习的粮食期货价格预测研究

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系统工程理论与实践 2021年第11期41卷 2837-2849页

作者：唐振鹏吴俊传张婷婷杜晓旭陈凯杰福州大学经济与管理学院福州350108

本文基于二次分解和集成学习的思想,构建VMD-EEMD-DE-ELM-DE-ELM组合模型,选取CBOT交易所上市的大豆,小麦及水稻期货作为国际粮食期货的代表,预测其未来收益率走势.鉴于目前已有研究均直接忽略VMD分解后残差项所含纳的重要信息,本文引... 详细信息

本文基于二次分解和集成学习的思想,构建VMD-EEMD-DE-ELM-DE-ELM组合模型,选取CBOT交易所上市的大豆,小麦及水稻期货作为国际粮食期货的代表,预测其未来收益率走势.鉴于目前已有研究均直接忽略VMD分解后残差项所含纳的重要信息,本文引入二次分解思想首次对其残差项进行EEMD二次分解、集成预测,改善其预测精度,进而提高模型整体预测精度.同时,针对现有组合模型预测方法采用等权重重构分量预测结果的缺陷,本文借鉴集成学习的思想,引入DE-ELM元学习器优化预测重构权重,优化模型全局预测表现.实证结果发现:本文提出的混合模型相较参照组模型具有显著的预测优势.

关键词：粮食期货预测二次分解集成学习

Controlled synthesis of one-dimensional segmented heteronanostructures

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Science China Materials 2024年第8期67卷 2715-2716页

作者： Zhiyong tang CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China

Telluride materials possess distinctive advantages,including the high theoretical volume capacity and electrical conductivity,rendering them promising candidates for a range of energy storage and optoelectronic applications[1].Heterogeneous compositions and interfaces in heteronanostructures have significant implications on the electron transport,magnetic coupling,and phonon scattering,thereby promoting the performances in photocatalysis,and thermoelectrics[2].

关键词： synthesis rendering thereby

A supramolecular self-assembly material based on cucurbituril and cationic TPE as ultra-sensitive probe of energetic pentazolate salts

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Defence Technology（防务技术） 2024年第5期35卷 69-76页

作者： Boan tang Jingxiang Zhong Shutao Wang Shiyu Zhou Yongxing tang Wei Huang School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China

The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic ***,the detection methods for these energetic materials based on the pentazolate anion are quite ***,two fluorescent probes for cyclo-N-5anion were *** 1(TPE2N)was synthesized with a tetraphenylethylene functionalized by two cationic groups which can generate strong electrostatic interactions with pentazolate anion and result in specific fluorescent *** 2 was designed based on sensor 1 and supramolecular cucurbit[7]uril(CB[7]).The unique structural features of CB[7]provide sites for the interaction between the cations and N-5anion in its cavity,which would generate a platform for the detection and enhance the recognition *** titration calorimetry(ITC)experiment and fluorescence titration experiment indicate the binding molar ratio between sensor 1 with CB[7]is 1:*** sensors display typical aggregation-induced emission(AIE)features and good *** sensors demonstrate excellent sensitivity to pentazole hydrazine salt with high enhancement constant(sensor 1:1.34×10^(6);sensor 2:3.78×10^(6))and low limit of detection(LOD:sensor 1=4.33μM;sensor 2=1.54μM).The formation of an AIE-based supramolecular sensor effectively improves the sensitivity to *** addition,the probes also have good selectivity of N-5anion *** research would shed some light on the design of novel fluorescent sensors to detect pentazolate-based molecules and provides an example of supramolecular chemistry combined with fluorescent probes.

关键词： Pentazolate anion Explosives detection Aggregation-induced emission(AIE) Host-guest interaction

Flexible and Robust Functionalized Boron Nitride/Poly(p‑Phenylene Benzobisoxazole)Nanocomposite Paper with High Thermal Conductivity and Outstanding Electrical Insulation

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Nano-Micro Letters 2024年第2期16卷 423-437页

作者： Lin tang Kunpeng Ruan Xi Liu Yusheng tang Yali Zhang Junwei Gu Chongqing Key Laboratory of Green Synthesis and Applications College of ChemistryChongqing Normal UniversityChongqing 401331People’s Republic of China Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China

With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming *** this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation *** obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered ***λ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),***,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.

关键词： Poly(p-phenylene-2,6-benzobisoxazole)nanofiber Boron nitride Thermal conductivity Electrical insulation

Markovian Quadratic BSDEs with an Unbounded Sub-quadratic Growth

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 441-462页

作者： Jingnan JU Shanjian tang Shanghai Center for Mathematical Sciences Fudan UniversityShanghai 200433China Department of Finance and Control Sciences School of Mathematical SciencesFudan UniversityShanghai 200433China

This paper is devoted to the solvability of Markovian quadratic backward stochastic differential equations(BSDEs for short)with bounded terminal *** generator is allowed to have an unbounded sub-quadratic growth in the second unknown variable *** existence and uniqueness results are given to these *** an application,an existence result is given to a system of coupled forward-backward stochastic differential equations with measurable coefficients.

关键词： Markovian BSDE Quadratic growth Unbounded sub-quadratic term coeficients Coupled FBSDE

A novel cascaded H-bridge photovoltaic inverter with flexible arc suppression function

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Global Energy Interconnection 2024年第4期7卷 513-527页

作者： Junyi tang Wei Gao College of Electrical Engineering and Automation Fuzhou UniversityFuzhou 350108P.R.China

This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding *** compensate for ground currents through an arc-elimination function,while outputting a PV direct current(DC)power *** method effectively reduces the residual grounding *** reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was *** online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection ***,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation *** results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding *** to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.

关键词： Photovoltaic inverter Flexible arc suppression Adaptive control Fuzzy neural network Sliding mode control Exit strategy

Single-cell RNA sequencing in juvenile idiopathic arthritis

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Genes & Diseases 2024年第2期11卷 633-644页

作者： Xiwen Luo Xuemei tang Department of Rheumatology and Immunology Children’s Hospital of Chongqing Medical UniversityChongqing 400014China Chongqing Key Laboratory of Child Infection and Immunity Ministry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqing 400014China

Juvenile idiopathic arthritis (JIA) is one of the most common chronic inflammatory rheumatic diseases in children,with onset before age 16 and lasting for more than 6 *** is a highly heterogeneous condition with various consequences for health and quality of *** some JIA patients,early detection and intervention remain *** a result,further investigation of the complex and unknown mechanisms underlying JIA is *** in technology now allow us to describe the biological heterogeneity and function of individual cell populations in *** this review,we hope to provide novel ideas and potential targets for the diagnosis and treatment of JIA by summarizing the current findings of single-cell RNA sequencing studies and understanding how the major cell subsets drive JIA pathogenesis.

关键词： Juvenile idiopathic arthritis Macrophage Macrophage activation syndrome Monocyte Single-cell RNA sequencing Synoviocyte T cell

Supported Recyclable Metal-free Frustrated Lewis Pair Catalyst for Catalytic Hydrogenation of Substituted Pyridines to Piperidines

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Chemical Research in Chinese Universities 2024年第4期40卷 682-689页

作者： MA Shaohua tang Zhiyong CAS Key Laboratory for Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

The construction of heterogeneous frustrated Lewis pairs(FLPs)catalysts is crucial for realizing highly efficient and recyclable pyridines catalytic *** this work,we prepared a recyclable heterogenous FLPs catalyst CMP-BF with conjugated microporous polymer CMP-ethynyl as the support via self-catalyzed 1,1-carboboration reaction with commercial Lewis acid B(C_(6)F_(5))_(3).The as-synthesized CMP-BF demonstrates superior heterogenous catalytic hydrogenation performance(conversion>99%),and considerable stability(84%conversion after three cycles)in recyclable hydrogenation of 2,*** work provides insights into the fabrication and catalytic application of recyclable heterogenous FLP catalysts.

关键词： Pyridine hydrogenation Frustrated Lewis pair Conjugated microporous polymer

High-precision modeling of tide-induced 3-D magnetic field and analysis of geomagnetic satellite orbit requirements

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Science China Earth Sciences 2024年第1期67卷 165-178页

作者： Zhengyong REN Cong YANG Hongbo YAO Xu tang Jingtian tang Keke ZHANG Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of Education Central South UniversityChangsha 410083China Hunan Key Laboratory of Nonferrous Resources and Geological Hazards Exploration Changsha 410083China School of Geosciences and Info-Physics Central South UniversityChangsha 410083China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China

Ground-based magnetic observatories and geomagnetic satellites can observe the induced magnetic field generated by the motion of seawater containing sodium and chlorine *** the three-dimensional(3-D)spatial distribution of tide-induced magnetic fields(TIMF)is crucial for inverting the electrical conductivity structure of the oceanic *** also serves as an essential basis for designing optimal geomagnetic observatories and satellite ***,existing methods for simulating TIMF suffer from limitations in inaccurately modeling realistic coastlines,heterogeneous land and sea surface properties,and complex deep Earth structures,thereby the interpretational level of TIMF data is *** overcome this issue,we developed a tetrahedral-based finite element method for simulating TIMF,which can efficiently approximate realistic coastlines,heterogeneous land and sea surface properties,and complex deep Earth ***,we derived the boundary value problem for the seawater motion-induced electromagnetic field,which was solved using the vector finite element method based on tetrahedral ***,using the latest ocean depth and seafloor sediment layer models,we constructed a 3-D conductivity model of the Earth,which includes realistic coastlines,heterogeneous land and sea conductivity *** then computed the TIMF using the M_(2)tidal source as an example and validated our method by comparing it with results obtained from spherical harmonic finite element and integral equation ***,utilizing the computed high-precision M_(2),N_(2),and O1 TIMF signals,we marked global observatories capable of observing strong M_(2),N_(2),and O1 TIMF signals and predicted alternative stations suitable for tide signal ***,we calculated TIMF at heights of 450 and 200 km for the Macao Science Satellite 1 and its subsequent *** results indicate that the amplitude of the tidal-induced magnetic field at

关键词： Ocean motional induction Electromagnetic induction Ocean tides Geomagnetic satellite Macao Science Satellite 1