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Existence of long-range magnetic order in Heisenberg spin nanoribbons with edge modification

Communications in Theoretical Physics 2024年第7期76卷 134-144页

作者： Da-cheng Ma Ling-yi Cui Chu-xiao Sun Xiao-dan Chi zheng-nan xianyu An Du College of Science Northeastern UniversityShenyang 110819China Department of Basic Science Dalian Naval AcademyDalian 116018China Department of Physics College of SciencesShenyang University of Chemical TechnologyShenyang 110142China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityChina Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationChina

Long-range magnetic order appears on a side decorated Heisenberg spin nanoribbon at nonzero temperature,although no spontaneous magnetization exists in a one-or two-dimensional isotropic Heisenberg model at any nonzero temperature according to the Mermin-Wagner *** use of the spin Green's function method,we calculated the magnetizations of Heisenberg nanoribbons decorated by side spins with single-ion anisotropy and found that the system exhibits a nonzero transition temperature,whether the decorated edge spins of the system link together or separate from each *** the width of the nanoribbon achieves infinite limit,the transition temperatures of the system tend to the same finite constant eventually whether one edge or both edges are decorated by side spins in the *** results reveal that the magnetism of a low-dimensional spin system is different from that of a threedimensional spin *** the single-ion anisotropy of edge spins in a Heisenberg spin nanoribbon can be modulated by an electric field experimentally,various useful long-range magnetic orders of the system can be *** work can provide a detailed theoretical basis for designing and fabricating next-generation low-dimensional magnetic random-access memory.

关键词： nanoribbon magnetic anisotropy long-range magnetic order Heisenberg model transition temperature

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Magnetic Properties of XXZ Heisenberg Antiferromagnetic and Ferrimagnetic nanotubes

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Communications in Theoretical Physics 2018年第12期69卷 823-828页

作者： zheng-nan xianyu An Du College of Sciences Northeastern University

The spin-1/2 antiferromagnetic and spin-(1/2, 1) ferrimagnetic single-walled nanotubes are described by XXZ Heisenberg model. The sublattice magnetization and the critical temperature of the system are calculated by using the double-time spin Green's function method. At zero temperature, with the increase of the exchange interaction in the circumferential direction, a maximum value appears in the sublattice magnetization curves of antiferromagnetic and ferrimagnetic systems. As the diameter of the tube increases, the spin quantum fluctuations and thermal fluctuations are suppressed. In addition, the spin quantum fluctuation of the spin-1/2 antiferromagnetic system is greater than that of the spin-(1/2, 1) ferrimagnetic system. The critical temperature of the system increases firstly and then tends to a constant with the increase of the diameter of tube, and it decreases to zero as the exchange anisotropy of the system disappears.

关键词： nanotube XXZ Heisenberg model quantum fluctuation thermal fluctuation critical temperature

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Light-triggered fluorochromic cholesteric liquid crystal elastomer with hydrogen-bonded fluorescent switch: dualmodal-switchable circularly polarized luminescence

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Science China Chemistry 2024年第8期67卷 2719-2727页

作者： Siyang Lin Tianqi Ren xianyu Meng Wenxin Kang Jinbao Guo Key Laboratory of Carbon Fibers and Functional Polymers Ministry of EducationCollege of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China

Solid materials with dynamically tunable circularly polarized luminescence(CPL) feature higher security levels and devicefriendly characteristics, showing great superiority in the field of information technology and anti-counterfeiting. To address the limited photoisomerization of fluorescent photoswitch in CPL-active solid materials, here a cholesteric liquid crystal elastomer(CLCE) containing a hydrogen-bonded(H-bonded) polymerizable fluorescent switch AHBA-PSD is prepared. Owing to the good flexibility and low glass-transition temperature of CLCE, AHBA-PSD shows a fast and fully reversible photocyclization/cycloreversion with fluorochromic behavior in CLCE. Further, by controlling the spectral overlapping area between the emission and reflection bands, the CLCE exhibits a strong CPL with a g_(lum) value of up to 0.76 accompanied by a reversible phototunable CPL signal. Meanwhile, the H-bond helps to stabilize the mechanical property, and the force-induced switching-off of CPL signal could be achieved due to the destroyed helical structures by external force. Finally, an automatically-recognized identification card with abundant chiroptical information is demonstrated.

关键词： cholesteric liquid crystal elastomer circularly polarized luminescence fluorescent photoswitch diarylethene photoismerization

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Spatiotemporal Evaluation and Future Projection of Diurnal Temperature Range over the Tibetan Plateau in CMIP6 Models

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Advances in Atmospheric Sciences 2024年第11期41卷 2245-2258页

作者： Suguo ZHANG Qin HU Xianhong MENG Yaqiong LÜ xianyu YANG School of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information TechnologyChengdu 610225China Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China Earth System Modelling School of Engineering and DesignTechnical University of MunichMunich 85521Germany

The diurnal temperature range(DTR) serves as a vital indicator reflecting both natural climate variability and anthropogenic climate change. This study investigates the historical and projected multitemporal DTR variations over the Tibetan Plateau. It assesses 23 climate models from phase 6 of the Coupled Model Intercomparison Project(CMIP6) using CN05.1 observational data as validation, evaluating their ability to simulate DTR over the Tibetan Plateau. Then, the evolution of DTR over the Tibetan Plateau under different shared socioeconomic pathway(SSP) scenarios for the near,middle, and long term of future projection are analyzed using 11 selected robustly performing models. Key findings reveal:(1) Among the models examined, BCC-CSM2-MR, EC-Earth3, EC-Earth3-CC, EC-Earth3-Veg, EC-Earth3-Veg-LR,FGOALS-g3, FIO-ESM-2-0, GFDL-ESM4, MPI-ESM1-2-HR, MPI-ESM1-2-LR, and INM-CM5-0 exhibit superior integrated simulation capability for capturing the spatiotemporal variability of DTR over the Tibetan Plateau.(2) Projection indicates a slightly increasing trend in DTR on the Tibetan Plateau in the SSP1-2.6 scenario, and decreasing trends in the SSP2-4.5, SSP3-7.0, and SPP5-8.5 scenarios. In certain areas, such as the southeastern edge of the Tibetan Plateau, western hinterland of the Tibetan Plateau, southern Kunlun, and the Qaidam basins, the changes in DTR are relatively large.(3) Notably, the warming rate of maximum temperature under SSP2-4.5, SSP3-7.0, and SPP5-8.5 is slower compared to that of minimum temperature, and it emerges as the primary contributor to the projected decrease in DTR over the Tibetan Plateau in the future.

关键词： Tibetan Plateau CMIP6 models diurnal temperature range model assessment historical period future projection

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Joint Optimization for on-Demand Deployment of UAVs and Spectrum Allocation in UAVs-Assisted Communication

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China Communications 2024年第7期21卷 278-290页

作者： Chen Yong Liao Naiwen WangWei Zhang xianyu Zhang Yu College of Communication Engineering Army Engineering University of PLANanjing 210007China The Sixty-Third Research Institute National University of Defense TechnologyNanjing 210007China

To improve the efficiency and fairness of the spectrum allocation for ground communication assisted by unmanned aerial vehicles(UAVs),a joint optimization method for on-demand deployment and spectrum allocation of UAVs is proposed,which is modeled as a mixed-integer non-convex optimization problem(MINCOP).An algorithm to estimate the minimum number of required UAVs is firstly proposed based on the pre-estimation and simulated *** MINCOP is then decomposed into three sub-problems based on the block coordinate descent method,including the spectrum allocation of UAVs,the association between UAVs and ground users,and the deployment of ***,the optimal spectrum allocation is derived based on the interference mitigation and channel *** association between UAVs and ground users is optimized based on local iterated optimization.A particle-based optimization algorithm is proposed to resolve the subproblem of the UAVs *** results show that the proposed method could effectively improve the minimum transmission rate of UAVs as well as user fairness of spectrum allocation.

关键词： block coordinate descent method on-demand deployment spectrum allocation UAVs-assisted Communication

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Large Eddy Simulation of Vertical Structure and Size Density of Deep Layer Clouds

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Advances in Atmospheric Sciences 2024年第8期41卷 1629-1642,1668-1670页

作者： Bangjun CAO xianyu YANG Jun WEN Qin HU Ziyuan ZHU School of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225China Institute for Geophysics and Meteorology University of CologneCologne 50923Germany

In a convective scheme featuring a discretized cloud size density, the assumed lateral mixing rate is inversely proportional to the exponential coefficient of plume size. This follows a typical assumption of-1, but it has unveiled inherent uncertainties, especially for deep layer clouds. Addressing this knowledge gap, we conducted comprehensive large eddy simulations and comparative analyses focused on terrestrial regions. Our investigation revealed that cloud formation adheres to the tenets of Bernoulli trials, illustrating power-law scaling that remains consistent regardless of the inherent deep layer cloud attributes existing between cloud size and the number of clouds. This scaling paradigm encompasses liquid, ice, and mixed phases in deep layer clouds. The exponent characterizing the interplay between cloud scale and number in the deep layer cloud, specifically for liquid, ice, or mixed-phase clouds, resembles that of shallow convection,but converges closely to zero. This convergence signifies a propensity for diminished cloud numbers and sizes within deep layer clouds. Notably, the infusion of abundant moisture and the release of latent heat by condensation within the lower atmospheric strata make substantial contributions. However, this role in ice phase formation is limited. The emergence of liquid and ice phases in deep layer clouds is facilitated by the latent heat and influenced by the wind shear inherent in the middle levels. These interrelationships hold potential applications in formulating parameterizations and post-processing model outcomes.

关键词： deep layer cloud cloud spatial structure cloud size density large eddy simulation

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Fine classification of rice paddy using multitemporal compact polarimetric SAR C band data based on machine learning methods

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Frontiers of Earth Science 2024年第1期18卷 30-43页

作者： xianyu GUO Junjun YIN Kun LI Jian YANG Huimin ZOU Fukun YANG School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China

Rice is an important food crop for human *** distinguishing different varieties and sowing methods of rice on a large scale can provide more accurate information for rice growth monitoring,yield estimation,and phenological monitoring,which has significance for the development of modern *** polarimetric(CP)synthetic aperture radar(SAR)provides multichannel information and shows great potential for rice monitoring and ***,the use of machine learning methods to build classification models is a controversial *** this paper,the advantages of CP SAR data,the powerful learning ability of machine learning,and the important factors of the rice growth cycle were taken into account to achieve high-precision and fine classification of rice ***,CP SAR data were simulated by using the seven temporal RADARSAT-2 C-band data ***,20-two CP SAR parameters were extracted from each of the seven temporal CP SAR data *** addition,we fully considered the change degree of CP SAR parameters on a time scale(ΔCP_(DoY)).Six machine learning methods were employed to carry out the fine classification of rice *** results show that the classification methods of machine learning based on multitemporal CP SAR data can obtain better results in the fine classification of rice paddies by considering the parameters ofΔCP_(DoY).The overall accuracy is greater than 95.05%,and the Kappa coefficient is greater than *** them,the random forest(RF)and support vector machine(SVM)achieve the best results,with an overall accuracy reaching 97.32%and 97.37%,respectively,and Kappa coefficient values reaching 0.965 and 0.966,*** the two types of rice paddies,the average accuracy of the transplant hybrid(T-H)rice paddy is greater than 90.64%,and the highest accuracy is 95.95%.The average accuracy of direct-sown japonica(D-J)rice paddy is greater than 92.57%,and the highest accuracy is 96.13%.

关键词： compact polarimetric(CP)SAR rice paddy machine learning fine classification multitemporal

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A Constrained Local Neighborhood Approach for Efficient Markov Blanket Discovery in Undirected Independent Graphs

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Computers, Materials & Continua 2024年第8期80卷 2535-2555页

作者： Kun Liu Peiran Li Yu Zhang JiaRen Ming Li xianyu Wang Cong Li School of Information and Communication Engineering Hainan UniversityHaikou570228China National Key Laboratory of Science and Technology on Space Microwave China Academy of Space Technology Xi’anXi’an710100China Strategic Emerging Industries Department CRSC Communication&Information Group Co.Ltd.Beijing100070China Military Representative Bureau of the Army Equipment Department in Xi’an Xi’an710032China

When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm *** constraint-based methods typically rely on the results of conditional independence ***,excessive reliance on these test results can lead to a series of problems,including increased computational complexity and inaccurate results,especially when dealing with large-scale networks where performance bottlenecks are particularly *** overcome these challenges,we propose a Markov blanket discovery algorithm based on constrained local neighborhoods for constructing undirected independence *** method uses the Markov blanket discovery algorithm to refine the constraints in the initial search space,sets an appropriate constraint radius,thereby reducing the initial computational cost of the algorithm and effectively narrowing the initial solution ***,the method first determines the local neighborhood space to limit the search range,thereby reducing the number of possible graph structures that need to be *** process not only improves the accuracy of the search space constraints but also significantly reduces the number of conditional independence *** performing conditional independence tests within the local neighborhood of each node,the method avoids comprehensive tests across the entire network,greatly reducing computational *** the same time,the setting of the constraint radius further improves computational efficiency while ensuring *** to other algorithms,this method can quickly and efficiently construct undirected independence graphs while maintaining high *** simulation results show that,this method has significant advantages in obtaining the structure of undirected independence graphs,not only maintaining an accuracy of over 96%but also reducing the number of conditi

关键词： Bayesian network structure learning Markov blanket conditional independence

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How to auction carbon emission allowances?A dynamic simulation analysis of spatiotemporal heterogeneity

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Frontiers of Engineering Management 2024年第3期11卷 430-454页

作者： xianyu YU Luxi XU Dequn ZHOU Qunwei WANG Xiuzhi SANG Xinhuan HUANG College of Economics and Management Nanjing University of Aeronautics and AstronauticsNanjing 211106China Research Centre for Soft Energy Science Nanjing University of Aeronautics and AstronauticsNanjing 211106China SchoolofEconomics FujianNormalUniversityFuzhou350117China

There is notable variability in carbon emission reduction efforts across different provinces in China,underscoring the need for effective strategies to implement carbon emission allowance *** auctions,as opposed to free allocations,could be more aligned with the principle of“polluter pays.”Focusing on three diverse regions—Ningxia,Beijing,and Zhejiang—this study employs a system dynamics simulation model to explore markets for carbon emissions and green certificates *** aim is to determine the optimal timing and appropriate policy intensities for auction *** findings include:(1)Optimal auction strategies differ among the provinces,recommending immediate implementation in Beijing,followed by Ningxia and Zhejiang.(2)In Ningxia,there’s a potential for a 6.20%increase in GDP alongside a 21.59%reduction in carbon emissions,suggesting a feasible harmony between environmental and economic objectives.(3)Market-related policy variables,such as total carbon allowances and Renewable Portfolio Standards,significantly influence the optimal auction strategies but have minimal effect on carbon auction prices.

关键词： carbon allowances carbon allowance auctions carbon emissions trading Renewable Portfolio Standard system dynamics

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Poly(ferulic acid)nanocarrier enhances chemotherapy sensitivity of acute myeloid leukemia by selectively targeting inflammatory macrophages

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Chinese Chemical Letters 2024年第9期35卷 289-295页

作者： Weijian Zhang xianyu Deng Liying Wang Jian Wang Xiuting Guo Lianggui Huang Xinyi Wang Jun Wu Linjia Jiang Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhou 510120China Department of Otolaryngology Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhou 510120China Department of Hematology The Seventh Affiliated HospitalSun Yat-sen UniversityShenzhen 518107China Department of Pediatrics Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhou 510120China Bioscience and Biomedical Engineering Thrust The Hong Kong University of Science and Technology(Guangzhou)NanshaGuangzhou 511400China Division of Life Science The Hong Kong University of Science and TechnologyHong Kong SAR 999077China

Macrophages,as a subset of innate immune cells,play a pivotal role in the initiation,maintenance,and resolution of inflammatory responses during tissue damage repair,defense against infections,and tumor ***,the mechanisms by which macrophages regulate inflammation in acute myeloid leukemia(AML)and their involvement in the chemotherapeutic effect remain *** this study,we have identified that AML cells stimulate macrophage expansion by activating the colony-stimulating factor 1 receptor(CSF1R)*** expanded macrophages activate nuclear factor kappa-B(NFκB)to induce the expression of inflammatory factors,thereby maintaining leukemic cell quiescence and promoting cell survival following ***,we have successfully utilized a poly(ferulic acid)nanocarrier to selectively target macrophages for inhibiting the NFκB-mediated inflammation,ultimately enhancing chemotherapy efficacy against *** together,our findings highlight the crucial role of macrophage-induced inflammation in conferring chemoresistance to AML,and demonstrate the potential of a targeted nanocarrier specifically designed for inflammatory macrophages to improve the AML chemotherapeutic outcomes.

关键词： Acute myeloid leukemia Chemoresistance Macrophage Inflammation NFκB

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