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Variational approach to Arnold diffusion

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Science China Mathematics 2019年第11期62卷 2103-2130页

作者： chong-qing cheng Jinxin Xue Department of Mathematics Nanjing UniverisityNanjing 10009&China Yau Mathematical Sciences Center Tsinghua UniversityBeijing 100084China

Arnold diffusion was conjectured by Arnol’d(1964) as a typical phenomena of topological instability in classical mechanics. In this paper, we give a panorama of the researches on Arnold diffusion using the variationa... 详细信息

关键词： Arnold diffusion Aubry set normal hyperbolicity normal form variational methods genericity

Arnold diffusion for nearly integrable Hamiltonian systems

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Science China Mathematics 2023年第8期66卷 1649-1712页

作者： chong-qing cheng Jinxin Xue School of Mathematical Sciences Nanjing Normal UniversityNanjing210023China Department of Mathematical Sciences Tsinghua UniversityBeijing100084China

In this paper,we prove that the nearly integrable system of the form H(x,y)=h(y)+εP(x,y),x∈T^(n),y∈T^(n),n≥3 admits orbits that pass through any finitely many prescribed small balls on the same energy level H^(-1)(E)provided that E>min h,if h is convex,andεP is *** settles the Arnold diffusion conjecture for convex systems in the smooth *** also prove the counterpart of Arnold diffusion for the Riemannian metric perturbation of the flat torus.

关键词： Arnold diffusion normal form Aubry set normally hyperbolic invariant cylinder cohomological equivalence ladder

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近可积Hamilton系统动力学的多样性

中国科学：数学 2020年第10期50卷 1437-1454页

作者：程崇庆南京大学数学系南京210093

近可积Hamilton系统的研究被Poincaré称为动力学的基本问题.自20世纪中叶以来,相关研究取得了巨大进展.Kolmogorov定理的建立和Arnold扩散现象的发现是其中的两大里程碑,极大地深化了我们对于近可积Hamilton系统动力学多样性的理解.本... 详细信息

近可积Hamilton系统的研究被Poincaré称为动力学的基本问题.自20世纪中叶以来,相关研究取得了巨大进展.Kolmogorov定理的建立和Arnold扩散现象的发现是其中的两大里程碑,极大地深化了我们对于近可积Hamilton系统动力学多样性的理解.本文将就相关内容作简要介绍.

关键词： Hamilton系统 Kolmogorov定理 Arnold扩散

Higher-dimensional integrable deformations of the classical Boussinesq-Burgers system

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Communications in Theoretical Physics 2024年第6期76卷 1-12页

作者： Xiaoyu cheng qing Huang School of Mathematics Northwest UniversityXi'an 710127China

In this paper,the(1+1)-dimensional classical Boussinesq-Burgers(CBB)system is extended to a(4+1)-dimensional CBB system by using its conservation laws and the deformation *** Lax integrability,symmetry integrability and a large number of reduced systems of the new higher-dimensional system are ***,for illustration,an exact solution of a(1+1)-dimensional reduced system is constructed from the viewpoint of Lie symmetry analysis and the power series method.

关键词： classical Boussinesq-Burgers system higher-dimensional system deformation algorithm Lax pair conservation law

Market Equilibrium Based on Cloud-edge Collaboration

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 96-104页

作者： Tong cheng Haiwang Zhong qing Xia the State Key Laboratory of Power Systems the Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

Market participants can only bid with lagged information disclosure under the existing market mechanism,which can lead to information asymmetry and irrational market behavior,thus influencing market *** promote rational bidding behavior of market participants and improve market efficiency,a novel electricity market mechanism based on cloudedge collaboration is proposed in this *** market information,called residual demand curve,is published to market participants in real-time on the cloud side,while participants on the edge side are allowed to adjust their bids according to the information disclosure prior to closure *** proposed mechanism can encourage rational bids in an incentive-compatible way through the process of dynamic equilibrium while protecting participants’*** paper further formulates the mathematical model of market equilibrium to simulate the process of each market participant’s strategic bidding behavior towards equilibrium.A case study based on the IEEE 30-bus system shows the proposed market mechanism can effectively guide bidding behavior of market participants,while condensing exchanged information and protecting privacy of participants.

关键词： Cloud-edge collaboration market mechanism residual demand curve strategic bidding

Rational design multi-color-emissive chemiluminescent carbon nanodots in a single solvothermal reaction

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Nano Research 2024年第6期17卷 4651-4660页

作者： Guang-Song Zheng cheng-Long Shen Yuan Deng Kai-Kai Liu Jin-Hao Zang Lin Dong qing Lou chong-Xin Shan Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Materials PhysicsMinistry of Educationand School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China

Recently,the chemiluminescence(CL)induced by carbon nanodots(CDs)has intrigued researchers’extensive interests in various applications due to its special light emission ***,the difficulty of synthesizing chemiluminescent CDs with full-spectrum emission severely hinders the further regulation of the CL emission ***,the multi-color-emissive chemiluminescent CDs are rational designed and further synthesized by regulating the sp2-hybrid core and sp3-hybrid surface from the citrate-ammonia molecular in a single solvothermal *** experimental characterizations and density functional theory calculations reveal that the higher temperature can promote the crosslinking polymerization/carbonization of carbon core and the higher protonation of solvent can determine the core size of final CDs,resulting in the variant CL emission from molecular-,crosslinking-and ***,the CL emission of the CDs can be further synthesized by tuning the luminescence chromophores in the formation process via regulating the temperature and solvent,enabling the applications of the CL CDs in illumination and information *** study paves a new technology to understand the luminescence of CDs and affords an industry translational potential over traditional chemiluminescent molecular.

关键词： carbon nanodots chemiluminescence regulation energy level alignment mechanism

Open-Shell Oligomers and Polymers: Theory, Characterization Methods, Molecular Design, and Applications

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Chinese Journal of Polymer Science 2024年第4期42卷 417-436页

作者： Xue-qing Wang cheng Song Ting Lei Key Laboratory of Polymer Chemistry and Physics(Ministry of Education) School of Materials Science and EngineeringPeking UniversityBeijing100871China

Open-shell oligomers and polymers have exhibited intriguing electronic and magnetic properties, making them highly desirable for a wide range of applications, including ambipolar organic field-effect transistors (OFETs), photodetectors, organic thermoelectrics, and spintronics. Although open-shell ground states have been observed in certain small molecules and doped organic semiconductors, the exploration of open-shell ground-state conjugated polymers is still limited, and the strategies for designing these polymers remain obscure. This review aims to briefly introduce the theory and characterization methods of open-shell conjugated polymers, along with an overview of recent progress and applications. The objective is to stimulate further advancements and investigations in this promising area by shedding light on the potential of open-shell conjugated polymers and the challenges that lie ahead.

关键词： Conjugated polymers Open-shell molecules High-spin ground state Donor-acceptor(D-A)polymers Optoelectronic and magnetic properties

Evaluating different levels of information on the calibration of building energy simulation models

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Building Simulation 2024年第4期17卷 657-676页

作者： Siyu cheng Zeynep Duygu Tekler Hongyuan Ji Wenxin Li Adrian chong Department of the Built Environment College of Design and EngineeringNational University of Singapore4 Architecture DriveSingapore117566Singapore School of Civil Engineering and Architecture Chongqing University of Science and TechnologyChongqing401331China School of Energy and Environment Southeast UniversityNanjing210096China

A poorly calibrated model undermines confidence in the effectiveness of building energy simulation, impeding the widespread application of advanced energy conservation measures (ECMs). Striking a balance between information-gathering efforts and achieving sufficient model credibility is crucial but often obscured by ambiguities. To address this gap, we model and calibrate a test bed with different levels of information (LOI). Beginning with an initial model based on building geometry (LOI 1), we progressively introduce additional information, including nameplate information (LOI 2), envelope conductivity (LOI 3), zone infiltration rate (LOI 4), AHU fan power (LOI 5), and HVAC data (LOI 6). The models are evaluated for accuracy, consistency, and the robustness of their predictions. Our results indicate that adding more information for calibration leads to improved data fit. However, this improvement is not uniform across all observed outputs due to identifiability issues. Furthermore, for energy-saving analysis, adding more information can significantly affect the projected energy savings by up to two times. Nevertheless, for ECM ranking, models that did not meet ASHRAE 14 accuracy thresholds can yield correct retrofit decisions. These findings underscore equifinality in modeling complex building systems. Clearly, predictive accuracy is not synonymous with model credibility. Therefore, to balance efforts in information-gathering and model reliability, it is crucial to (1) determine the minimum level of information required for calibration compatible with its intended purpose and (2) calibrate models with information closely linked to all outputs of interest, particularly when simultaneous accuracy for multiple outputs is necessary.

关键词： calibration building energy simulation(BES) energy conservation measure(ECM) level of information field measurements

Effect of biochar application on rice,wheat,and corn seedlings in hydroponic culture

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Journal of Environmental Sciences 2024年第1期135卷 379-390页

作者： Yingjie Yin Jikai Li Sihang Zhu qing Chen chong Chen Yukui Rui Jianying Shang College of Land Science and Technology China Agricultural UniversityKey Laboratory of Plant-Soil InteractionsMinistry of Educationand Key Laboratory of Arable Land Conservation in North ChinaMinistry of Agriculture and Rural AffairsBeijing 100193China Agricultural Management Institute Ministry of Agriculture and Rural AffairsBeijing 102208China College of Resources and Environmental Sciences China Agricultural UniversityBeijing Key Laboratory of Farmland Soil Pollution Prevention and RemediationBeijing 100193China

In recent years,biochar has attracted considerable attention for soil quality improvement and carbon sequestration due to its unique physicochemical ***,the mechanism by which biochar application negatively affects the growth of crop seedlings has not been fully *** this study,a hydroponic experiment was conducted to evaluate the response of rice,wheat,and corn seedlings to biochar application(CK,0 g/L;BC1,0.5 g/L;and BC2,1.0 g/L).Compared with the CK treatment,the BC1 and BC2 treatments decreased the fresh shoot and root weights of rice and corn seedlings(P0.05).For the contents of nutrient elements in seedlings,both BC1 and BC2 treatments hindered the roots from absorbing Fe and Cu and increased the uptake of Ca and *** with the CK treatment,the translocation factor(TF)values of Ca,Mn,and Zn were significantly decreased especially in rice seedlings(35.3%-36.8%,68.7%-76.5%,and 29.8%-22.0%,respectively)under the BC1 and BC2 treatments,while only Mn was significantly decreased in wheat and corn seedlings(P<0.05).Transmission electron microscope(TEM)analysis of root cross-sections showed that nano-sized biochar particles(10~23 nm)were found in the root cells under BC2 treatment *** findings reveal that a large amount of biochar application can reduce nutrient absorption and translocation,and hinder rice,wheat,and corn seedlings,particularly rice seedling,in hydroponic system.

关键词： Biochar Toxicity Seedling growth Hydroponic cultivation