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Stochastic resonance of spinor condensates in optical cavity

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 80-87页

作者： Zheng-Chun Li Bixuan Fan Lu Zhou weiping zhang School of Physics and Astronomy and Tsung-Dao Lee InstituteShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Precision Spectroscopy School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China College of Physics and Communication Electronics Jiangxi Normal UniversityNanchang 330022China Shanghai Branch Hefei National LaboratoryShanghai 201315China Shanghai Research Center for Quantum Sciences Shanghai 201315China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

Stochastic resonance is a phenomenon in which adding random noise to a system enhances the detection or transmission of a weak signal. It occurs when the noise interacts with the system's nonlinearity, thus improving signal-to-noise ratio and increasing sensitivity. Although parametric resonances in an atomic spinor Bose-Einstein condensate have been investigated, the question of whether one can observe stochastic resonance in such a system persists. In this study we propose a scheme for generating stochastic resonance in a cavity-spinor Bose-Einstein condensate coupling system. We demonstrate stochastic resonance through numerical calculations using the mean-field theory and truncated Wigner approximation methods. Furthermore, the characteristics of the system's response to noise and periodic signals are studied in detail. This study unravels a new scheme for observing stochastic resonance via linking atomic many-body physics with cavity quantum electrodynamics.

关键词： spinor condensate stochastic resonance optical cavity

Differential response of radial growth and δ^(13)C in Qinghai spruce(Picea crassifolia) to climate change on the southern and northern slopes of the Qilian Mountains in Northwest China

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Journal of Forestry Research 2024年第3期35卷 205-218页

作者： Li Qin Huaming Shang weiping Liu Yuting Fan Kexiang Liu Tongwen zhang Ruibo zhang Key Laboratory of Tree-Ring Physical and Chemical Research(Cma)/Xinjiang Key Laboratory of Tree-Ring Ecology Institute of Desert MeteorologyChina Meteorological AdministrationUrimqi 830002People's Republicof China Xinjiang Meteorological Information Center Urimqi 830002People's Republic of China

Tree radial growth can have significantly differ-ent responses to climate change depending on the *** elucidate the effects of climate on radial growth and stable carbon isotope(δ^(13)C)fractionation of Qing-hai spruce(Picea crassifolia),a widely distributed native conifer in northwestern China in different environments,we developed chronologies for tree-ring widths and δ^(13)C in trees on the southern and northern slopes of the Qilian Mountains,and analysed the relationship between these tree-ring variables and major climatic ***-ring widths were strongly influenced by climatic factors early in the growing season,and the radial growth in trees on the northern slopes was more sensitive to climate than in trees on the ***-ring δ^(13)C was more sensitive to climate than radial growth.δ^(13)C fractionation was mainly influenced by summer temperature and precipitation early in the growing *** conductance more strongly limited stable carbon isotope fractionation in tree rings than photosynthetic rate *** response between tree rings and climate in mountains gradually weakened as climate *** in radial growth and stable carbon isotope fractionation of *** in response to climate in the Qilian Mountains may be further complicated by continued climate change.

关键词： Tree rings Qinghai spruce(Picea crassifolia Kom.) Stable carbon isotope(δ^(13)C) Qilian Mountains:Climate change

Route selection for opportunity-sensing and prediction of waterlogging

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Frontiers of Computer Science 2024年第4期18卷 147-159页

作者： Jingbin WANG Weijie zhang Zhiyong YU Fangwan HUANG weiping ZHU Longbiao CHEN College of Computer and Data Science Fuzhou UniversityFuzhou 350108China Department of Computer Science and Technology Xiamen UniversityXiamen 361005China

Accurate monitoring of urban waterlogging contributes to the city’s normal operation and the safety of residents’daily ***,due to feedback delays or high costs,existing methods make large-scale,fine-grained waterlogging monitoring impossible.A common method is to forecast the city’s global waterlogging status using its partial waterlogging *** method has two challenges:first,existing predictive algorithms are either driven by knowledge or data alone;and second,the partial waterlogging data is not collected selectively,resulting in poor *** overcome the aforementioned challenges,this paper proposes a framework for large-scale and fine-grained spatiotemporal waterlogging monitoring based on the opportunistic sensing of limited bus *** framework follows the Sparse Crowdsensing and mainly comprises a pair of iterative predictor and *** predictor uses the collected waterlogging status and the predicted status of the uncollected area to train the graph convolutional neural *** combines both knowledge-driven and data-driven approaches and can be used to forecast waterlogging status in all regions for the upcoming *** selector consists of a two-stage selection procedure that can select valuable bus routes while satisfying budget *** experimental results on real waterlogging and bus routes in Shenzhen show that the proposed framework could easily perform urban waterlogging monitoring with low cost,high accuracy,wide coverage,and fine granularity.

关键词： waterlogging prediction sparse crowdsensing active learning route selection graph convolutional network

Elastohydrodynamic Lubrication Interface Stiffness and Damping Considering Asperity Lateral Contact

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Acta Mechanica Solida Sinica 2024年第1期37卷 109-123页

作者： Zhiqiang Gao Yu zhang Xian Wei Yanfang Zhu Lixia Peng weiping Fu Wen Wang School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an 710048China School of Intelligent manufacturing Panzhihua UniversityPanzhihua 617000China material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Light Chemical TechnologyYibin 644002China School of Mechanical Engineering Anyang Institute of TechnologyAnyang 455099China

Elastohydrodynamic lubrication(EHL)point contact occurs between two rough surfaces at the mesoscopic level,while the interaction of rough surfaces involves contact between asperities at the microscale *** most cases,the contact between asperities within an interface takes the form of lateral contact rather than peak *** devoid of contact asperities are filled with lubricating ***,conventional models often oversimplify lateral contact forms as interactions between asperities and a smooth,rigid *** simplifications fail to accurately represent the true contact conditions and can lead to inaccuracies in the analysis of EHL’s contact *** address this issue,we have developed a novel EHL interface model comprising two rough *** model allows us to explore the influence of asperity height,contact angle,and contact azimuth angle on EHL interface performance.

关键词： EHL interface Asperity lateral contact Contact stiffness Damping

Bio-Based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

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Engineering 2024年第5期36卷 250-263页

作者： Jianzhong ma Li ma Lei zhang Wenbo zhang Qianqian Fan Buxing Han College of Bioresources Chemical and materials Engineering Shaanxi University of Science and TechnologyXi’an 710021China Xi’an Key Laboratory of Green Chemicals and Functional materials Xi’an 710021China College of Chemistry and Chemical Engineering Shaanxi University of Science and TechnologyXi’an 710021China Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry and Technology Shaanxi University of Science and TechnologyXi’an 710021China Institute of Chemistry Chinese Academy of SciencesBeijing 100190China

This study presents a solvent-free,facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin(MV)using *** resulting MV not only imparted antibacterial properties to coatings layered on leather,but could also be employed as a green alternative to petroleum-based carcinogen styrene(St).Herein,MV was copolymerized with butyl acrylate(BA)to obtain waterborne bio-based P(MV-BA)miniemulsion via miniemulsion ***,MXene nanosheets with excellent photothermal conversion performance and antibacterial properties,were introduced into the P(MV-BA)miniemulsion by ultrasonic *** the gradual solidification of P(MV-BA)/MXene nanocomposite miniemulsion on the leather surface,MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene,which prompted its full exposure to light and bacteria,exerting the maximum photothermal conversion efficiency and significant antibacterial *** particular,when the dosage of MXene nanosheets was 1.4 wt%,the surface temperature of P(MV-BA)/MXene nanocomposite miniemulsioncoated leather(PML)increased by about 15℃ in an outdoor environment during winter,and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100%under the simulated sunlight treatment for 30 ***,the introduction of MXene nanosheets increased the air permeability,water vapor permeability,and thermal stability of these *** study provides a new insight into the preparation of novel,green,and waterborne bio-based nanocomposite coatings for leather,with desired warmth retention and antibacterial *** can not only realize zerocarbon heating based on sunlight in winter,reducing the use of fossil fuels and greenhouse gas emissions,but also improve ability to fight off invasion by harmful bacteria,viruses,and other microorganisms.

关键词： MXene nanosheets Vanillin Styrene substitute Leather coating Photothermal conversion Warmth retention Antibacterial properties

Nuclear phylogenomics of angiosperms and insights into their relationships and evolution

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Journal of Integrative Plant Biology 2024年第3期66卷 546-578页

作者： Guojin zhang Hong ma College of Life Sciences Hunan Normal UniversityChangsha 410081China Department of Biology 510 Mueller LaboratoryHuck Institutes of the Life SciencesThe Pennsylvania State UniversityUniversity ParkPA 16802USA

Angiosperms(flowering plants) are by far the most diverse land plant group with over 300,000 species. The sudden appearance of diverse angiosperms in the fossil record was referred to by Darwin as the “abominable mystery,”hence contributing to the heightened interest in angiosperm evolution. Angiosperms display wide ranges of morphological, physiological,and ecological characters, some of which have probably influenced their species richness. The evolutionary analyses of these characteristics help to address questions of angiosperm diversification and require well resolved phylogeny. Following the great successes of phylogenetic analyses using plastid sequences,dozens to thousands of nuclear genes from next-generation sequencing have been used in angiosperm phylogenomic analyses, providing well resolved phylogenies and new insights into the evolution of angiosperms. In this review we focus on recent nuclear phylogenomic analyses of large angiosperm clades, orders, families,and subdivisions of some families and provide a summarized Nuclear Phylogenetic Tree of Angiosperm Families. The newly established nuclear phylogenetic relationships are highlighted and compared with previous phylogenetic results. The sequenced genomes of Amborella,Nymphaea, Chloranthus, Ceratophyllum, and species of monocots, magnoliids, and basal eudicots, have facilitated the phylogenomics of relationships among five major angiosperms clades. All but one of the 64 angiosperm orders were included in nuclear phylogenomics with well resolved relationships except the placements of several orders. Most families have been included with robust and highly supported placements, especially for relationships within several large and important orders and ***, we examine the divergence time estimation and biogeographic analyses of angiosperm on the basis of the nuclear phylogenomic frameworks and discuss the differences compared with previous analyses. Furthermore,we discuss the implicatio

关键词： angiosperms evolution flowering plants nuclear gene phylogenomics phylogeny

Effects of baffle position in serpentine flow channel on the performance of proton exchange membrane fuel cells

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Chinese Journal of Chemical Engineering 2024年第5期69卷 250-262页

作者： Guodong Xia Xiaoya zhang Dandan ma MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of TechnologyBeijing 100124China

This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstream(Case 3),downstream(Case 4),and the entire cathode flow channel(Case 5)to study the effects of baffle position on mass transport,power density,net power,***,the effects of back pressure and humidity on the voltage were *** showed that compared to smooth channels,the oxygen and water transport facilitation at the diffusion layer-channel interface were added 11.53%-20.60%and 7.81%-9.80%at 1.68 A·cm^(-2)by adding *** closer the baffles were to upstream,the higher the total oxygen flux,but the lower the flux uniformity the worse the water *** oxygen flux of upstream baffles was 8.14%higher than that of downstream baffles,but oxygen flux uniformity decreased by 18.96%at 1.68 A·cm^(-2).The order of water removal and voltage improvement was Case 4>Case 5>Case 3>Case 2>Case *** power of Case 4 was 9.87%higher than that of the smooth *** the Case 4,when the cell worked under low back pressure or high humidity,the voltage increments were *** potential increment for the back pressure of 0 atm was 0.9%higher than that of 2 atm(1 atm=101.325 kPa).The potential increment for the humidity of 100%was 7.89%higher than that of 50%.

关键词： Proton exchange membrane fuel cell Baffle position mass transfer Net power Uniformity Voltage increment

Partial regularity and nonlinear potential estimates for Stokes systems with super-quadratic growth

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Science China mathematics 2024年第7期67卷 1525-1554页

作者： Lingwei ma Zhenqiu zhang School of mathematical Sciences Tianjin Normal UniversityTianjin300387China School of mathematical Sciences and LPMC Nankai UniversityTianjin300071China

This paper builds a bridge between partial regularity theory and nonlinear potential theory for the following generalized stationary Stokes system with super-quadratic growth and continuous coefficients:-div A(x,Du)+■π=f,div u=0,where Du is the symmetric part of the gradient■*** first establish anε-regularity criterion involving both the excess functional of the symmetric gradient Du and Wolff potentials of the nonhomogeneous term f to guarantee the local vanishing mean oscillation(VMO)-regularity of Du in an open subset Ω_(u) of Ω with full *** anε-regularity criterion leads to a pointwise Wolff potential estimate of Du,which immediately infers that Du is partially C^(0)-regular under appropriate ***,we give a local continuous modulus estimate of Du.

关键词： nonlinear Stokes system partial regularity Wolff potential estimates continuous modulus estimates

Deciphering and integrating invariants for neural operator learning with various physical mechanisms

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National Science Review 2024年第4期11卷 111-122页

作者： Rui zhang Qi Meng Zhi-Ming ma Academy of mathematics and Systems Science Chinese Academy of Sciences(CAS) Microsoft Research

Neural operators have been explored as surrogate models for simulating physical systems to overcome the limitations of traditional partial differential equation(PDE) solvers. However, most existing operator learning methods assume that the data originate from a single physical mechanism, limiting their applicability and performance in more realistic scenarios. To this end, we propose the physical invariant attention neural operator(PIANO) to decipher and integrate the physical invariants for operator learning from the PDE series with various physical mechanisms. PIANO employs self-supervised learning to extract physical knowledge and attention mechanisms to integrate them into dynamic convolutional *** to existing techniques, PIANO can reduce the relative error by 13.6%–82.2% on PDE forecasting tasks across varying coefficients, forces or boundary conditions. Additionally, varied downstream tasks reveal that the PI embeddings deciphered by PIANO align well with the underlying invariants in the PDE systems, verifying the physical significance of PIANO.

关键词： neural operator PDE solver contrastive learning physical invariants