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Bifurcation analysis and control study of improved full-speed differential model in connected vehicle environment

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Chinese Physics B 2024年第7期33卷 245-266页

作者：艾文欢雷正清李丹洋方栋梁刘大为 College of Computer Science and Engineering Northwest Normal UniversityLanzhou 730070China College of Electrical Engineering Lanzhou Institute of TechnologyLanzhou 730050China

In recent years, the traffic congestion problem has become more and more serious, and the research on traffic system control has become a new hot spot. Studying the bifurcation characteristics of traffic flow systems and designing control schemes for unstable pivots can alleviate the traffic congestion problem from a new perspective. In this work, the full-speed differential model considering the vehicle network environment is improved in order to adjust the traffic flow from the perspective of bifurcation control, the existence conditions of Hopf bifurcation and saddle-node bifurcation in the model are proved theoretically, and the stability mutation point for the stability of the transportation system is found. For the unstable bifurcation point, a nonlinear system feedback controller is designed by using Chebyshev polynomial approximation and stochastic feedback control method. The advancement, postponement, and elimination of Hopf bifurcation are achieved without changing the system equilibrium point, and the mutation behavior of the transportation system is controlled so as to alleviate the traffic congestion. The changes in the stability of complex traffic systems are explained through the bifurcation analysis, which can better capture the characteristics of the traffic flow. By adjusting the control parameters in the feedback controllers, the influence of the boundary conditions on the stability of the traffic system is adequately described, and the effects of the unstable focuses and saddle points on the system are suppressed to slow down the traffic flow. In addition, the unstable bifurcation points can be eliminated and the Hopf bifurcation can be controlled to advance, delay, and disappear,so as to realize the control of the stability behavior of the traffic system, which can help to alleviate the traffic congestion and describe the actual traffic phenomena as well.

关键词： bifurcation analysis vehicle queuing bifurcation control Hopf bifurcation

NνDEx-100 conceptual design report

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Nuclear Science and Techniques 2024年第1期35卷 18-33页

作者： Xi-Guang Cao Yan-Long Chang Kai Chen Emilio Ciuffoli Li-Min Duan dong-liang fang Chao-Song Gao Surja K.Ghorui Peng-Chong Hu Qiang Hu Si-Yuan Huang Ze-Yu Huang Lei Lang Yu-Lan Li Zhi-Jie Li Tian-Yu liang Jun Liu Chen-Gui Lu Fa-Tai Mai Yuan Mei Hao Qiu Xiang-Ming Sun Xiao-Xing Tang Hu-Lin Wang Qian-Ming Wang Le Xiao Mu-Yun Xiao Jian-Yu Xin Nu Xu Peng Yang Yi-Chen Yang Zhen Yang Zong-Yang Yu dong-liang Zhang Jun-Wei Zhang Cheng-Xin Zhao Dou Zhu NνDEx-100 collaboration Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Lanzhou University Lanzhou 730000China Central China Normal University Wuhan 430079China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Lawrence Berkeley National Laboratory BerkeleyCA 94720USA North China University of Water Resources and Electric Power Zhengzhou 450045China 不详

Observing nuclear neutrinoless double beta (0vββ) decay would be a revolutionary result in particle *** such a decay would prove that the neutrinos are their own antiparticles,help to study the absolute mass of neutrinos,explore the origin of their mass,and may explain the matter-antimatter asymmetry in our universe by lepton number *** propose developing a time projection chamber (TPC) using high-pressure ^(82)SeF_(6) gas and Topmetal silicon sensors for readout in the China Jinping Underground Laboratory (CJPL) to search for neutrinoless double beta decay of82Se,called the NvDEx *** being located at CJPL with the world’s thickest rock shielding,NvDEx combines the advantages of the high Qββ(2.996 MeV) of82Se and the TPC’s ability to distinguish signal and background events using their different topological *** makes NvDEx unique,with great potential for low-background and high-sensitivity 0 vββ***-100,a NvDEx experiment phase with 100 kg of SeF_(6)gas,is being built,with plans to complete installation at CJPL by *** report introduces 0 vββ physics,the NvDEx concept and its advantages,and the schematic design of NvDEx-100,its subsystems,and background and sensitivity estimation.

关键词： Neutrinoless double beta decay Time projection chamber ^(82)SeF_(6) China Jinping Underground Laboratory

Calculation of microscopic nuclear level densities based on covariant density functional theory

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Nuclear Science and Techniques 2023年第9期34卷 118-127页

作者： Kun-Peng Geng Peng-Xiang Du Jian Li dong-liang fang College of Physics Jilin UniversityChangchun 130012China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

In this study,a microscopic method for calculating the nuclear level density(NLD)based on the covariant density functional theory(CDFT)is *** particle-hole state density is calculated by a combinatorial method using single-particle level schemes obtained from the CDFT,and the level densities are then obtained by considering collective effects such as vibration and *** results are compared with those of other NLD models,including phenomenological,microstatisti-cal and nonrelativistic Hartree–Fock–Bogoliubov combinatorial *** comparison suggests that the general trends among these models are essentially the same,except for some deviations among the different NLD *** addition,the NLDs obtained using the CDFT combinatorial method with normalization are compared with experimental data,including the observed cumulative number of levels at low excitation energies and the measured *** CDFT combinatorial method yields results that are in reasonable agreement with the existing experimental data.

关键词： Nuclear level density Covariant density functional theory Combinatorial method

Progressive meristem and single-cell transcriptomes reveal the regulatory mechanisms underlying maize inflorescence development and sex differentiation

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Molecular Plant 2024年第7期17卷 1019-1037页

作者： Yonghao Sun liang dong Lu Kang Wanshun Zhong David Jackson fang Yang National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhan 430070China Hubei Hongshan Laboratory Wuhan 430070China Cold Spring Harbor Laboratory Cold Spring HarborNY 11724USA School of Agriculture Sun Yat-Sen UniversityShenzhen 518107China

Maize develops separate ear and tassel inflorescences with initially similar morphology but ultimately different architecture and *** detailed regulatory mechanisms underlying these changes still remain largely *** this study,through analyzing the time-course meristem transcriptomes and floret single-cell transcriptomes of ear and tassel,we revealed the regulatory dynamics and pathways underlying inflorescence development and sex *** identified 16 diverse gene clusters with differential spatiotemporal expression patterns and revealed biased regulation of redox,programmed cell death,and hormone signals during meristem differentiation between ear and ***,based on their dynamic expression patterns,we revealed the roles of two RNA-binding proteins in regulating inflorescence meristem activity and axillary meristem ***,using the transcriptional profiles of 53910 single cells,we uncovered the cellular heterogeneity between ear and tassel *** found that multiple signals associatedwith either enhancedcell death or reduced growth are responsiblefortassel pistil suppression,while part of the gibberellic acid signal may act non-cell-autonomously to regulate ear stamen arrest during sex *** further showed that the pistil-protection gene SILKLESS 1(SK1)functions antagonistically to the known pistil-suppression genes through regulating common molecular pathways,and constructed a regulatory network for pistil-fate ***,our study provides a deep understanding of the regulatory mechanisms underlying inflorescence development and sex differentiation in maize,laying the foundation for identifying new regulators and pathways for maize hybrid breeding and improvement.

关键词： maize inflorescence floral organ sex differentiation single-cell RNA sequencing RNA-binding protein

Sufficient Conditions for Amalgamated 3-Manifolds to be ∂-Irreducible

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 161-172页

作者： Bing fang Fengchun LEI liang liang School of Mathematical Sciences Dalian University of TechnologyDalian 116024LiaoningChina School of Mathematics Liaoning Normal UniversityDalian 116029LiaoningChina

In this paper,the authors give some sufficient conditions for an amalgamated 3-manifold along a compact connected surface F with boundary to be ∂-irreducible in terms of distances between some kinds of vertex subsets ... 详细信息

关键词： ∂-Irreducibility Irreducibility Amalgamated 3-manifold Curve complex Arc complex

A Comparison of Conventional and Shear-Rate Dependent Mohr-Coulomb Models for Simulating Landslides

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Journal of Mountain Science 2014年第6期11卷 1478-1490页

作者： liang dong-fang HE Xu-zhen MOE Key Laboratory of Hydrodynamics Shanghai Jiao Tong University Department of Engineering University of Cambridge Trumpington StreetCambridge CB2 1PZ UK

Landslides may cause many fatalities and heavy economic losses,so it is vital to understand their mechanics so as to take appropriate measures to mitigate their ***,the loose soil behaves like frictional material in most circumstances,so Mohr-Coulomb type equations are often used to describe their ***,these models generally do not consider the influence of the shearrate on the Mohr-Coulomb friction angle,so the shear-rate dependence effect on the soil flow and landslide runout is not well *** paper reports on an application of the incompressible Smoothed Particle Hydrodynamics(SPH) method to the dynamics of dry granular *** traditional model with a constant friction angle is compared with the modified Mohr-Coulomb model with a variable friction angle related to the *** is found that the shear-rate dependence effect is negligible for shallow granular flows along mild *** steeper slopes of the ground and larger aspect ratios of the initial soil column,the rate-dependence effect becomes more important.

关键词：剪切速率模型模拟 Mohr-Coulomb模型莫尔库仑坡比山体滑坡粒子动力学

Impact of finite-range tensor terms in the Gogny force on theβ-decay of magic nuclei

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Nuclear Science and Techniques 2021年第7期32卷 83-89页

作者： Da-Zhuang Chen dong-liang fang Chun-Lin Bai College of Physics Sichuan UniversityChengdu 610065China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Effects of finite-range tensor force onβ-decay of magic and semimagic nuclei of^(34)Si,^(68,78)Ni,and^(132)Sn have been investigated using the self-consistent Hartree–Fock plus random-phase approximation *** tensor force shifts the low-lying Gamow–Teller states downward and systematically improves the calculations of Q and logft ***,it systematically reduces the deviations between the theoretical and experimental data and significantly improves the calculation ofβ-decay *** effect is similar to that of zero-range tensor force.

关键词： tensor decay finite

A New Method for Solving Nonlinear Partial Differential Equations Based on Liquid Time-Constant Networks

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Journal of Systems Science & Complexity 2024年第2期37卷 480-493页

作者： SUN Jiuyun dong Huanhe fang Yong College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

In this paper,physics-informed liquid networks(PILNs)are proposed based on liquid time-constant networks(LTC)for solving nonlinear partial differential equations(PDEs).In this approach,the network state is controlled via ordinary differential equations(ODEs).The significant advantage is that neurons controlled by ODEs are more expressive compared to simple activation *** addition,the PILNs use difference schemes instead of automatic differentiation to construct the residuals of PDEs,which avoid information loss in the neighborhood of sampling *** this method draws on both the traveling wave method and physics-informed neural networks(PINNs),it has a better physical ***,the KdV equation and the nonlinear Schr¨odinger equation are solved to test the generalization ability of the *** the best of the authors’knowledge,this is the first deep learning method that uses ODEs to simulate the numerical solutions of PDEs.

关键词： Nonlinear partial differential equations numerical solutions physics-informed liquid networks physics-informed neural networks

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Analysis and experimental study on resistance-increasing behavior of composite high efficiency autonomous inflow control device

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Petroleum Science 2024年第2期21卷 1290-1304页

作者： liang-liang dong Yu-Lin Zhang School of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina Oil and Gas Equipment Technology Sharing and Service Platform of Sichuan ProvinceChengdu610500SichuanChina

Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable *** structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production.

关键词： Water control Flow separation Flow resistance-increasing AICD device Simulation and experiment