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Spatiotemporal pattern formation in parametrically driven two-dimensional Bose–Einstein condensates

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Communications in Theoretical Physics 2024年第12期76卷 150-156页

作者： Jun Wan wen wen hui-jun Li College of Mechanics and Engineering Science Hohai University Institute of Nonlinear Physics and Department of Physics Zhejiang Normal University Zhejiang Institute of Photoelectronics and Zhejiang Institute for Advanced Light Source Zhejiang Normal University

We investigate spatiotemporal periodic patterns in harmonically trapped Bose–Einstein condensates(BECs) driven by a periodic modulation of the interaction. Resonant with the breathing mode, we show the emergence of a square lattice pattern containing two orthonormal stripes. We study the time evolutions of the lattice patterns for different driving strengths and dissipations. We find that its spatial periodicity and temporal oscillating frequency match the Bogoliubov dispersion, which is the intrinsic property of the system and relevant to the parametric amplification of elementary excitations. In the circumstances of strong driving strength and low dissipation, we further observe the triad interaction and the resulting superlattice state, which are well explained by the nonlinear amplitude equation for superimposed stripes. These results shed light on unexplored nonlinear spatiotemporal dynamics of two-dimensional patterns in harmonically trapped BECs that can pave the way for engineering exotic patterns by state-of-the-art experiments.

关键词： spatio-temporal periodicity square lattice pattern triad interaction

Improved sample added LMMSE receiver based on interference mitigation for HSDPA downlink

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The Journal of China Universities of Posts and Telecommunications 2008年第2期15卷 39-44页

作者： CHE wen ZHAO hui WANG wen-bo Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Beijing 100876 China

In the downlink of wideband code division multiple access （WCDMA） or WCDMA- high speed downlink packet access （HSDPA） system, the frequency reuse factor is equal to 1, which leads to more possible co-channel interference from neighbor cells. In this situation, user equipment（UE） with traditional receiver will suffer from significant performance degradation at the edge of the cell. To solve this problem, a receiver structure considering interference mitigation has been proposed for long term evolution（LTE） of third-generation partnership project （3GPP）. Such receiver makes use of all the interfering cells＇ channel information to perform a linear minimum mean square error （LMMSE） equalization algorithm. In this article, an improved equalization algorithm is presented, which simply adds more samples to perform one equalization operation. Simulations show that the proposed algorithm can obtain a considerable performance improvement in frequency selective fading channel, with relative little additional complexity introduced.

关键词： LMMSE HSDPA equalizer

The quasitriangular structures of biproduct Hopf algebras

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第1期8卷 149-157页

作者： ZHAO Li-hui ZHAO wen-zheng Department of Mathematics Zhejiang University Hangzhou 310027 China Department of Mathematics Henan Normal University Xinxiang 453002 China

The construction of the biproduct of Hopf algebras, which consists of smash product and the dual notion of smash coproduct, was first formulated by Radford. In this paper we study the quasitriangular structures over biproduct Hopf algebras B*H. We show the necessary and sufficient conditions for biproduct Hopf algebras to be quasitriangular. For the case when they are, we determine completely the unique formula of the quasitriangular structures. And so we find a way to construct solutions of the Yang-Baxter equation over biproduct Hopf algebras in the sense of (Majid, 1990).

关键词： Hopf algebra Quasitriangular structure Biproduct

Metal-Backboned Polymer:Conception,Design and Synthesis

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Chinese Journal of Polymer Science 2023年第1期41卷 3-6页

作者： Kai-wen Zeng hui-Sheng Peng State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science Fudan UniversityShanghai200438China

The backbones of polymers are generally composed of non-metal elements such as C,N,O and *** we propose and synthesize a new class of polymers whose backbones are completely made from metal atoms connected by chemical bonds,and they are thus named metal-backboned *** a demonstration,nickel is selected as the metal to construct the nickel-backboned polymers with varied lengths,which are verified by mass spectrometry and studied by ultraviolet-visible *** metal-bonded polymers open up a new avenue to develop functional polymers in the future.

关键词： Metal-backboned Nickel Functional Polymer

EXPONENTIAL CONVERGENCE OF SAMPLE AVERAGE APPROXIMATION METHODS FOR A CLASS OF STOCHASTIC MATHEMATICAL PROGRAMS WITH COMPLEMENTARITY CONSTRAINTS

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Journal of Computational Mathematics 2006年第6期24卷 733-748页

作者： Fan-wen Meng hui-fu Xu The Logistics Institute - Asia Pacific National University of Singapore 1 Law Link Singapore School of Mathematics University of Southampton Highfield Southampton S017 1B J UK School of Mathematics University of Southampton Highfield Southampton S017 1B J UK

In this paper, we propose a Sample Average Approximation （SAA） method for a class of Stochastic Mathematical Programs with Complementarity Constraints （SMPCC） recently considered by Birbil, G/irkan and Listes [3]. We study the statistical properties of obtained SAA estimators. In particular we show that under moderate conditions a sequence of weak stationary points of SAA programs converge to a weak stationary point of the true problem with probability approaching one at exponential rate as the sample size tends to infinity. To implement the SAA method more efficiently, we incorporate the method with some techniques such as Scholtes＇ regularization method and the well known smoothing NCP method. Some preliminary numerical results are reported.

关键词： Stochastic mathematical programs with complementarity constraints Sampleaverage approximation Weak stationary points Exponential convergence.

Nearly Uniform Design Construction on Flexible Region

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Acta Mathematicae Applicatae Sinica 2020年第3期36卷 557-565页

作者： Jian-hui NING wen-wen YIN Li PENG School of Mathematics and Statistics Center China Normal UniversityWuhan 430079China School of statistics Renmin University of ChinaBeijing 100872China Department of Statistics General Administration of Customs of the People's Republic of ChinaBeijing 100730China

In this paper,we deduced an iteration formula for the computation of central composite *** using the iteration formula,the computational complexity of uniform design construction in flexible region can be greatly *** we also made a refinement to threshold accepting algorithm to accelerate the algorithm's convergence *** show that the refined algorithm can converge to the lower discrepancy design more stably.

关键词： uniform design flexible region central composite discrepancy threshold accepting algorithm

Effect of non-stationary accretion on spectral state transitions:An example of a persistent neutron star LMXB 4U 1636–536

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Research in Astronomy and Astrophysics 2018年第3期18卷 91-98页

作者： hui Zhang wen-Fei Yu Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of Sciences

Observations of black hole and neutron star X-ray binaries show that the luminosity of the hard-to-soft state transition is usually higher than that of the soft-to-hard state transition,indicating additional parameters other than mass accretion rate are required to interpret spectral state *** has been found in some individual black hole or neutron star soft X-ray transients that the luminosity corresponding to the hard-to-soft state transition is positively correlated with the peak luminosity of the following soft state. In this work,we report the discovery of the same correlation in the single persistent neutron star low mass X-ray binary（LMXB） 4 U 1636–536 based on data from the All Sky Monitor（ASM） on board RXTE,the Gas Slit Camera（GSC） on board MAXI and the Burst Alert Telescope（BAT） on board Swift. We also found such a positive correlation holds in this persistent neutron star LMXB in a luminosity range spanning about a factor of four. Our results indicate that non-stationary accretion also plays an important role in driving X-ray spectral state transitions in persistent accreting systems with small accretion flares,which is much less dramatic compared with the bright outbursts seen in many Galactic LMXB transients.

关键词： accretion accretion disks - X-rays binaries - stars neutron

States and transitions in mixed networks

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Frontiers of physics 2014年第4期9卷 523-528页

作者： Ying Zhang wen-hui Wan Department of Physics Beijing Normal University Beijing 100875 China Department of Physics Beijing Institute of Technology Beijing 100081 China

A network is named as mixed network if it is composed of N nodes, the dynamics of some nodes are periodic, while the others are chaotic. The mixed network with all-to-all coupling and its correspond- ing networks after the nonlinearity gap-condition pruning are investigated. Several synchronization states are demonstrated in both systems, and a first-order phase transition is proposed. The mixture of dynamics implies any kind of synchronous dynamics for the whole network, and the inixed networks may be controlled by the nonlinearity gap-condition pruning.

关键词： mixed network phase transition synchronization state

Silk microfibrous mats with long-lasting antimicrobial function

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Journal of Materials Science & Technology 2021年第4期63卷 203-209页

作者： mi Wu wen Liu Jinrong Yao Zhengzhong Shao Xin Chen State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceLaboratory of Advanced MaterialsFudan UniversityShanghai 200433PR China

The controlled release of antibiotic drugs to injured sites has great advantages over the conventional intravenous administration of antibiotics,which is associated with systemic toxicity,for wound *** nanofibrous/microfibrous mats,with a similar structure to the native extracellular matrix,is a promising wound ***,drug-loaded halloysite nanotubes(HNTs)incorporated into regenerated silk fibroin(RSF)microfibrous mats were prepared by electrospinning to achieve sustained drug release and long-lasting antimicrobial protection.A broad-spectrum antibiotic,tetracycline hydrochloride(TCH),was selected as the model *** electron microscopic images revealed that the TCH-loaded HNTs were homogeneously embedded in the RSF electrospun microfibers without significant changes in *** drug release profiles showed that the RSF microfibrous mats with TCH-loaded HNTs exhibited a significantly reduced burst phase and a long release time over two weeks compared to the pure TCH-loaded HNTs and the TCH-loaded RSF microfibrous mats without *** results were attributed to the two-step release of TCH first from the HNTs and then RSF matrix in the electrospun ***,the antimicrobial properties of the RSF microfibrous mats with TCH-loaded HNTs were evaluated using both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli *** results demonstrated long-lasting antimicrobial activity for at least one week,showing the great potential of TCH-loaded RSF microfibrous mat as a wound dressing ***,these TCHloaded RSF microfibrous mats with excellent biocompatibility and sustained antimicrobial protection are extremely attractive systems for clinical applications.

关键词： loaded release sustained