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Study of thermal decoherence of harmonic oscillators

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原子与分子物理学报 2025年第5期42卷 108-114页

作者： LI jian ZHOU gao-Liang YAN Zheng-Xin LIU Wei WANG Zhao-Qi College of Science Xi’an University of Science and TechnologyXi’an 710054China

The thermal decoherence of harmonic oscillators is investigated *** quantum system presented here is a one-dimensional oscillator with angular frequency,which is surrounded by a thermal bath of environmental *** are various environmental oscillators with different angular frequency(below an ultraviolet cutoff).At the beginning,the quantum system is a pure state and the environmental oscillators are in thermodynamic equilibrium with *** a period,the system-environment interactions inspire significant decoherence of the quantum *** decoherence is displayed by explicit calculations of the purity and von Neumann entropy of the quantum *** is worth noting that the decoherence could be significant even in the weak coupling and low temperature case due to the large amount of environmental degrees of *** the decoherence process is inspired between the quantum system and an ordinary thermal environment here,the thermal decoherence result is quite general.

关键词： Quantum decoherence Grand canonical ensemble Oscillators

A Liutex based definition and identification of vortex core center lines

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Journal of Hydrodynamics 2019年第3期31卷 445-454页

作者： Yi-sheng gao jian-ming Liu Yi-fei Yu Chaoqun Liu Department of Mathematics University of Texas at Arlington Arlington Texas 76019 USA School of Mathematics and Statistics Jiangsu Normal University Xuzhou 221116 China

Six core issues for vortex definition and identification concern with (1) the absolute strength,(2) the relative strength,(3) the rotational axis,(4) the vortex core center,(5) the vortex core size, and (6) the vortex boundary (Liu C. 2019). However, most of the currently popular vortex identification methods, including the Q criterion, the criterion and the Acj criterion etc., are Eulerian local region-type vortex identification criteria and can only approximately identify the vortex boundary by somewhat arbitrary threshold. On the other hand, the existing Eulerian local line-type methods, which seek to extract line-type features such as vortex core line, are not entirely satisfactory since most of these methods are based on vorticity or pressure minimum that will fail in many cases. The key issue is the lack of a reasonable mathematical definition for vortex core center. To address this issue, a Liutex (previously named Rortex) based definition of vortex core center is proposed in this paper. The vortex core center, also called vortex rotation axis line here, is defined as a line where the Liutex magnitude gradient vector is aligned with the Liutex vector, which mathematically implies that the cross product of the Liutex magnitude gradient vector and the Liutex vector on the line is equal to zero. Based on this definition, a novel three-step method for extracting vortex rotation axis lines is presented. Two test cases, namely the Burgers vortex and hairpin vortices, are examined to justify the proposed method. The results demonstrate that the proposed method can successfully identify vortex rotation axis lines without any user-specified threshold, so that the proposed method is very straightforward, robust and efficient.

关键词： Vortex definition vortex identification flow visualization Liutex Liutex magnitude gradient vortex core lines

Evaluating the performance and influencing factors of three portable black carbon monitors for field measurement

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Journal of Environmental Sciences 2024年第5期139卷 320-333页

作者： Liqing Wu Yicheng Shen fei Che Yuzhe Zhang jian gao Chong Wang State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Jinan Ecological Environmental Protection Grid-Based Supervision Center Jinan 250013China

Black carbon(BC)is associated with adverse human health and climate *** BC spatial distribution imperatively requires low-cost and portable *** portable BC monitors are commercially available,but their accuracy and reliability are not always satisfactory during continuous field *** study evaluated three models of portable black carbon monitors,C12,MA350 and DST,and investigates the factors that affect their *** monitors were tested in urban Beijing,where portable devices running for one month alongside a regular-size reference aethalometer *** study considers several factors that could influence the monitors'performance,including ambient weather,aerosol composition,loading artifacts,and built-in *** results show that MA350and DST present considerable discrepancies to the reference instrument,mainly occurring at lower concentrations(0-500 ng/m^(3))and higher concentrations(2500-8000 ng/m^(3)),*** discrepancies were likely caused by the anomalous noise of MA350 and the loading artifacts of *** study also suggests that the ambient environment has limited influence on the monitors'performance,but loading artifacts and accompanying compensation algorithms can result in unrealistic *** on the evaluation,the study suggests that C12 is the best choice for unsupervised field measurement,DST should be used in scenarios where frequent maintenance is available,and MA350 is suitable for research purposes with post-processing *** study highlights the importance of assigning portable BC monitors to appropriate applications and the need for optimized real-time compensation algorithms.

关键词： Black carbon Aethalometer Loading artifact Performance evaluation Portable device

Investigation of the interior RC beam-column joints under monotonic antisymmetrical load

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1474-1494页

作者： fei gao Zhiqiang TANG Biao HU Junbo CHEN Hongping ZHU jian MA School of Civil Engineering and Mechanics Huazhong University of Science and TechnologyWuhan 430074China Guangdong Provincial Key L aboratory of Durability for Marine Civil Engineering Shenzhen UniversityShenzhen 518060China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

The paper presents numerical findings of reinforced concrete interior beam-column joints under monotonic antisymmetrical *** finite element models considered compression and tension damage were calibrated by test results in terms of the load-displacement,failure modes,and strains of longitudinal *** emphasis was put on studying the effects of hoop reinforcement ratio in joint core and the axial compression ratio on the responses of the *** results show that,in addition to the truss and strut-and-tie mechanisms,the confinement mechanism also existed in the joint core.A certain amount of stirrup is not only able to enhance the confinement in joint core,undertake a part of shear force and thus to increase the shear capacity,prevent the outward buckling of steel bars in column,improve the stress distribution in joint core,delay cracking and restrain the propagation of cracks,but also to increase the yield load,decrease the yield displacement of beam and improve the joint ***,excessive horizontal stirrups contribute little to the joint *** a certain range,larger axial compression ratio is beneficial for the joint mechanical behavior,while it is negative when axial compression ratio is too large.

关键词： RC beam-column joint reinforcement ratio in joint core axial compression ratio finite element test

A deep learning network for estimation of seismic local slopes

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Petroleum Science 2021年第1期18卷 92-105页

作者： Wei-Lin Huang fei gao jian-Ping Liao Xiao-Yu Chuai State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum-BeijingBeijing 102249China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijig 100083China Hunan Provincial Key Laboratory of Shale Gas Resource Utilization Hunan University of Science and TechnologyXiangtan 411201China Hebei Coal Research Institute Co. LtdJizhong Energy GroupXingtai 054000China

The local slopes contain rich information of the reflection geometry,which can be used to facilitate many subsequent procedures such as seismic velocities picking,normal move out correction,time-domain imaging and structural *** the slope estimation is achieved by manually picking or scanning the seismic profile along various *** present here a deep learning-based technique to automatically estimate the local slope map from the seismic *** the presented technique,three convolution layers are used to extract structural features in a local window and three fully connected layers serve as a classifier to predict the slope of the central point of the local window based on the extracted *** deep learning network is trained using only synthetic seismic data,it can however accurately estimate local slopes within real seismic *** examine its feasibility using simulated and real-seismic *** estimated local slope maps demonstrate the succes sful performance of the synthetically-trained network.

关键词： Deep learning Neural network Seismic data Local slopes

Synthesis and Structure of a Series of Ti_(6)-oxo Clusters Functionalized by in situ Esterified Dicarboxylate Ligands

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Chinese Journal of Chemistry 2021年第5期39卷 1259-1264页

作者： Mei-Yan gao Yayong Sun fei Wang jian Zhang Lei Zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian 350002China Department of Chemical Sciences Bernol InstituteUniversity of LimerickLimerickRepublic of Ireland

In this work,a series of titanium-oxo clusters functionalized by in sitw formed esterified ligands,Ti_(6)(μ_(2)-O)_(2)(μ_(3)-O)_(2)(O^(i)Pr)_(10)(0_(3)P-Phen)_(2)(THA^(i)Pr)_(2)(PTC-267;THA=cis-1,2,3,6-tetrahydrophthalic anhydride),Ti_(6)(μ_(2)-O)_(2)(μ_(3)-O)_(2)(O^(i)Pr)_(10)(0_(3)P-Phen)_(2)(THA^(i)Pr)_(2)(PTC-268 and PTC-269;PDA=3;4-pyridinedicarboxylic acid)and Ti_(6)(μ_(2)-O)_(2)(μ_(4)-O)_(2)(O^(i)Pr)_(10)(cat)_(2)(THA^(i)Pr)_(2)(PTC-270;cat=catechol),were successfully synthesized by one-step solvothermal ***-267,PTC-268 and PTC-269 possess a similar{Ti_(6)(μ_(2)-O)_(2)(μ_(3)-O)_(2)}core,while the core of PTC-270 is composed of a unique{Ti_(6)(μ_(4)-O)_(2)(μ_(2)-O)_(2)}***-268 and PTC-269 occur as geometric isomers with each ***,these complexes offer rare examples of dicarboxylate-modified polyoxo-titanium clusters(PTCs)with ester *** work not only offers an opportunity to gain an insight into the formation mechanism of PTCs,but also contributes to the exploration of optimal synthetic conditions for high-nuclearity PTCs.

关键词： Cluster compounds Ester groups Dicarboxylate ligands Titanium Crystal engineering

Modeling and Analyzing Dynamic Response for An Offshore Bottom-Fixed Wind Turbine with Individual Pitch Control

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China Ocean Engineering 2022年第3期36卷 372-383页

作者： XIE Shuang-yi ZHANG Kai-fei HE Jiao gao jian ZHANG Cheng-lin College of Mechanical Engineering Chongqing University of TechnologyChongqing 400044China School of Mechanical and Power Engineering Chongqing University of Science&TechnologyChongqing 401331China Beijing Institute of Precision Mechatronics and Controls Beijing 100076China Fishery Machinery and Instrument Research Institute Chinese Academy of Fishery SciencesShanghai 200092China College of Engineering Science and Technology Shanghai Ocean UniversityShanghai 201306China

The asymmetric or periodically varying blade loads resulted by wind shear become more significant as the blade length is increased to capture more wind ***,compared with the onshore wind turbines,their offshore counterparts are subjected to additional wave loadings in addition to wind loadings within their ***,vibration control and fatigue load mitigation are crucial for safe operation of large-scale offshore wind *** view of this,a multi-body model of an offshore bottom-fixed wind turbine including a detailed drivetrain is established in this ***,an individual pitch controller(IPC)is designed using disturbance accommodating *** feedback is used to add damping in flexible modes of concern,and a state estimator is designed to predict unmeasured ***,a coupled aero-hydro-servo-elastic model is *** on this coupled model,the load reduction effect of IPC and the dynamic responses of the drivetrain are *** results showed that the designed IPC can effectively reduce the structural loads of the wind turbine while stabilizing the turbine power ***,it is found that the drivetrain dynamic responses are improved under IPC.

关键词： wind turbine individual pitch controller disturbance accommodating control multi-body modeling drivetrain

Simulation and Field Testing of Multiple Vehicles Collision Avoidance Algorithms

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IEEE/CAA Journal of Automatica Sinica 2020年第4期7卷 1045-1063页

作者： Chaoyue Zu Chao Yang jian Wang Wenbin gao Dongpu Cao fei-Yue Wang the College of Computer Science and Technology Jilin UniversityChangchun 130012China jiangsu XCMG Construction Machinery Research Institute Ltd. Xuzhou 221004China the College of Computer Science and Technology Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of EducationJilin UniversityChangchun 130012 Chongqing Xibu Automobile Proving Ground Management Co.Ltd. Chongqing 404100China the State Grid JIBEI Electric Power Company Limited Management Training Center China the Advanced Vehicle Engineering Center Cranfield UniversityCranfield MK430ALUK the State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China

A global planning algorithm for intelligent vehicles is designed based on the A* algorithm, which provides intelligent vehicles with a global path towards their destinations. A distributed real-time multiple vehicle collision avoidance(MVCA)algorithm is proposed by extending the reciprocal n-body collision avoidance method. MVCA enables the intelligent vehicles to choose their destinations and control inputs independently,without needing to negotiate with each other or with the coordinator. Compared to the centralized trajectory-planning algorithm, MVCA reduces computation costs and greatly improves the robustness of the system. Because the destination of each intelligent vehicle can be regarded as private, which can be protected by MVCA, at the same time MVCA can provide a real-time trajectory planning for intelligent vehicles. Therefore,MVCA can better improve the safety of intelligent vehicles. The simulation was conducted in MATLAB, including crossroads scene simulation and circular exchange position simulation. The results show that MVCA behaves safely and reliably. The effects of latency and packet loss on MVCA are also statistically investigated through theoretically formulating broadcasting process based on one-dimensional Markov chain. The results uncover that the tolerant delay should not exceed the half of deciding cycle of trajectory planning, and shortening the sending interval could alleviate the negative effects caused by the packet loss to an extent. The cases of short delay(< 100100 ms) and low packet loss(< 5%) can bring little influence to those trajectory planning algorithms that only depend on V2 V to sense the context, but the unpredictable collision may occur if the delay and packet loss are further worsened. The MVCA was also tested by a real intelligent vehicle, the test results prove the operability of MVCA.

关键词： Collision avoidance intelligent vehicles intervehicle communication simulation testing trajectory planning

Role of oxygen vacancy inducer for graphene in graphene-containing anodes

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Frontiers of Chemical Science and Engineering 2023年第3期17卷 326-333页

作者： fei Wang jian Mao College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Currently,graphene is only considered as a conductive additive and expansion inhibitor in oxides/graphene composite *** this study,a new graphene role(oxygen vacancy inducer)in graphene/oxides composites anodes,which are treated at high-temperature,is proposed and verified using experiments and density functional theory *** high-temperature processing,graphene forms carbon vacancies due to increased thermal vibration,and the carbon vacancies capture oxygen atoms,facilitating the formation of oxygen vacancies in ***,the induced oxygen vacancy concentrations can be regulated by sintering temperatures,and the behavior is unaffected by oxide crystal structures(crystalline and amorphous)and morphology(size and shape).According to density functional theory calculations and electrochemical measurements,the oxygen vacancies enhance the lithiumion storage *** findings can result in a better understanding of graphene’s roles in graphene/oxide composite anodes,and provide a new method for designing high-performance oxide anodes.

关键词： oxide oxygen vacancy graphene anode density functional theory calculation