检索结果-南通市图书馆

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2024年第07期76卷 136-146页

作者： Da-cheng Ma Ling-yi Cui Chu-xiao Sun Xiao-dan Chi Zheng-Nan XianYu An Du college of Science Northeastern University department of Basic Science Dalian Naval Academy department of physics College of Sciences Shenyang University of Chemical Technology National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Key Laboratory of Data Analytics and Optimization for Smart Industry(northeastern university) Ministry of Education

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 theorem. By 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 other. When 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 nanoribbon. The results reveal that the magnetism of a low-dimensional spin system is different from that of a three-dimensional spin system. When 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 obtained. This work can provide a detailed theoretical basis for designing and fabricating next-generation low-dimensional magnetic random-access memory.

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

Cavity optomechanics with directionally squeezed light

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2024年第6期67卷 181-182页

作者： Pierre Meystre department of physics and college of Optical sciences University of ArizonaTucson 85721USA

It is well understood that the Heisenberg uncertainty principle imposes a fundamental limit on the precision of quantum *** way to get around this difficulty is to exploit quantum states that minimize the uncertainty on the observable of interest,increasing in the process the uncertainty on the conjugate *** states of the electromagnetic field.

关键词： field observable quantum

维普期刊数据库

同方期刊数据库

Parity-dependent skin effects and topological properties in the multilayer nonreciprocal Su−Schrieffer−Heeger structures

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第3期19卷 115-133页

作者： Jia-Rui Li Cui Jiang Han Su Di Qi Lian-Lian Zhang Wei-Jiang Gong college of sciences Northeastern UniversityShenyang 110819China Basic department Shenyang Institute of EngineeringShenyang 110136China

We concentrate on the skin effects and topological properties in the multilayer non-Hermitian Su−Schrieffer−Heeger (SSH) structure, by taking into account the nonreciprocal couplings between the different sublattices in the unit cells. Following the detailed demonstration of the theoretical method, we find that in this system, the skin effects and topological phase transitions induced by nonreciprocal couplings display the apparent parity effect, following the increase of the layer number of this SSH structure. On the one hand, the skin effect is determined by the parity of the layer number of this SSH system, as well as the parity of the band index of the bulk states. On the other hand, for the topological edge modes, such an interesting parity effect can also be observed clearly. Next, when the parameter disorders are taken into account, the zero-energy edge modes in the odd-layer structures tend to be more robust, whereas the other edge modes are easy to be destroyed. In view of these results, it can be ascertained that the findings in this work promote to understand the influences of nonreciprocal couplings on the skin effects and topological properties in the multilayer SSH lattices.

关键词： multilayer SSH lattice nonreciprocal couplings band structure skin effect

Reconstruction of aether scalar tensor theory for variouscosmological scenarios

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese physics C 2024年第4期48卷 202-208页

作者：付启铭何梦慈眭陶陶张鑫 Institute of physics Shaanxi University of TechnologyHanzhong 723000China college of physics Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Cosmology and Astrophysics(Liaoning)&college of sciences Northeastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Ministry of Education) Northeastern UniversityShenyang 110819China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China

In this paper,we present several explicit reconstructions for the aether scalar tensor(AeST)theory derived from the background of the Friedmann-Lemaître-Robertson-Walker cosmological *** is shown that the Einstein-Hilbert Lagrangian with a positive cosmological constant is the only Lagrangian capable of accurately replicating the exact expansion history of theΛcold dark matter(ΛCDM)universe filled solely with dust-like ***,theΛCDM-era can be produced within the framework of the AeST theory for some other fluids,including a perfect fluid with p=−(1/3)ρ,multifluids,and nonisentropic perfect ***,we demonstrate that theΛCDM-era can be replicated with no real matter field for the AeST *** cosmic evolution resulting from both the power-law and de-Sitter solutions can also be obtained.

关键词： reconstruction modified gravity cosmology

维普期刊数据库

Constructing long-cycling crystalline C_(3)N_(4)-based carbonaceous anodes for sodium-ion battery via N configuration control

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第1期6卷 159-171页

作者： Ying Wang Hongguan Li Shuanlong Di Boyin Zhai Ping Niu Antonios Kelarakis Shulan Wang Li Li School of Metallurgy Northeastern UniversityShenyangLiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyangLiaoningChina department of Chemistry College of ScienceNortheastern UniversityShenyangLiaoningChina School of Natural sciences UCLan Research Centre for Smart MaterialsUniversity of Central LancashirePrestonUK Foshan Graduate School of Innovation Northeastern UniversityFoshanGuangdongChina

Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability strongly restrict their practical *** carbon nitrides with conductive carbon may relieve these ***,little is known about the influence of nitrogen(N)configurations on the interactions between carbon and C_(3)N_(4),which is fundamentally critical for guiding the precise design of advanced C_(3)N_(4)-related ***,highly crystalline C_(3)N_(4)(poly(triazine imide),PTI)based all-carbon composites were developed by molten salt *** importantly,the vital role of pyrrolic-N for enhancing charge transfer and boosting Na+storage of C_(3)N_(4)-based composites,which was confirmed by both theoretical and experimental evidence,was spot-highlighted for the first *** elaborately controlling the salt composition,the composite with high pyrrolic-N and minimized graphitic-N content was *** from the formation of highly crystalline PTI and electrochemically favorable pyrrolic-N configurations,the composite delivered an unusual reverse growth and record-level cycling stability even after 5000 cycles along with high reversible capacity and outstanding full-cell capacity *** work broadens the energy storage applications of C_(3)N_(4) and provides new prospects for the design of advanced all-carbon electrodes.

关键词： anode highly crystalline C_(3)N_(4) N configuration sodium-ion batteries ultra-long cyclic stability

Exploring luminescence quenching on lanthanide-doped nanoparticles through changing the spatial distribution of sensitizer and activator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第5期17卷 4517-4524页

作者： Jiwei Li Yao Xie Renrui Sun Junxun Zhou Lining Sun department of Chemistry College of SciencesShanghai UniversityShanghai 200444China department of physics College of SciencesShanghai UniversityShanghai 200444China School of Medicine Shanghai UniversityShanghai 200444China

Luminescence quench is common in overdoped upconversion *** methods have been proposed to counteract the adverse effects of concentration quenching on luminescence,but in upconversion nanoparticles that are highly doped with both sensitizers and activators,the factors that contribute to the diminishing of the emission cannot be summarized by a single ***,a core-shell design is used to spatially separate the sensitizer(Yb^(3+))and activator(Er^(3+))and to modulate the emission by changes in the distribution position as well as the concentration of the dopant ions in order to probe the factors affecting the *** the sensitizer ions are located in the core,the luminescence intensity of the nanoparticles is significantly weaker than that of the other distribution,which implies that the effect of sensitizer and activator on luminescence in the highly doped state has a different and more complex *** intensity of the emission is more affected by Yb^(3+)than Er^(3+),which includes not only the self-quenching of Yb^(3+),but also the dominance in the Yb^(3+)-Er^(3+)*** this finding may provide new ideas for revealing the reasons for the diminished luminescence of highly doped upconversion nanoparticles and thus for enhancing luminescence.

关键词： upconversion luminescence lanthanide ion core-shell nanoparticles concentration quenching cross-relaxation

Dynamic analysis and bifurcation control of a delayed fractional-order eco-epidemiological migratory bird model with fear effect

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2024年第3期17卷 1-33页

作者： Caihong Song Ning Li college of sciences Northeastern University 110819 ShenyangLiaoningP.R.China

In this paper,a new delayed fractional-order model including susceptible migratory birds,infected migratory birds and predators is proposed to discuss the spread of diseases among migratory *** of predators is considered in the model,as fear can reduce the reproduction rate and disease transmission rate among ***,some basic mathematical results of the proposed model are ***,time delay is regarded as a bifurcation parameter,and the delay-induced bifurcation conditions for such an uncontrolled system are established.A novel periodic pulse feedback controller is proposed to suppress the bifurcation *** is found that the control scheme can successfully suppress the bifurcation behavior of the system,and the pulse width can be arbitrarily selected on the premise of ensuring the control *** with the traditional time-delay feedback controller,the control scheme proposed in this paper has more advantages in practical application,which not only embodies the advantages of low control cost and easy operation but also caters to the periodic changes of the *** proposed control scheme,in particular,remains effective even after the system has been disrupted by a *** simulation verifies the correctness of the theoretical results.

关键词： Delayed fractional-order migratory birds fear Hopf bifurcation periodic pulse feedback

Host-guest cocrystals boost thermally activated delayed fluorescence materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年

作者： Wenzhi Yang Jiong Zhou department of Chemistry College of Sciences Northeastern UniversityShenyang

Organic light-emitting diodes(OLEDs) play an important role in organic display and lighting fields. Thermally activated delayed fluorescence(TADF) materials have shown great potential in the OLED field because they can theoretically achieve 100% utilization of excitons and avoid heavy metal pollution problems [1]. However, the construction of a full-color-tunable system for TADF materials is still a challenging task because of the uncontrollability and unpredictability of intermolecular charge-transfer(CT) states.

关键词：

Implications of the Stellar Mass Density of High-z Massive Galaxies from JWST on Warm Dark Matter

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第1期24卷 128-134页

作者： Hengjie Lin Yan Gong Bin Yue Xuelei Chen National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China university of Chinese Academy of sciences Beijing 100049China Science Center for China Space Station Telescope National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China department of physics College of SciencesNortheastern UniversityShenyang 110819China Center for High Energy physics Peking UniversityBeijing 100871China

A significant excess of the stellar mass density at high redshift has been discovered from the early data release of James Webb Space Telescope(JWST),and it may require a high star formation ***,this will lead to large number density of ionizing photons in the epoch of reionization(EoR),so that the reionization history will be changed,which can arise tension with the current EoR *** dark matter(WDM),via the free streaming effect,can suppress the formation of small-scale structure as well as low-mass *** provides an effective way to decrease the ionizing photons when considering a large star formation efficiency in high-z massive galaxies without altering the cosmic reionization *** the other hand,the constraints on the properties of WDM can be derived from the JWST *** this work,we study WDM as a possible solution to reconcile the JWST stellar mass density of high-z massive galaxies and reionization *** find that,the JWST high-z comoving cumulative stellar mass density alone has no significant preference for either CDM or WDM *** using the observational data of other stellar mass density measurements and reionization history,we obtain that the WDM particle mass with mw=0.51_(-0.12)^(+0.22) keV and star formation efficiency parameter f_(*)^(0)> 0.39 in 2σ confidence level can match both the JWST high-z comoving cumulative stellar mass density and the reionization history.

关键词： Cosmology (cosmology:)dark matter (cosmology:)large-scale structure of universe

维普期刊数据库