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Pulse Evolution Characteristics in Self-Similar Mode-locked Fibre Laser

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Chinese physics Letters 2007年第11期24卷 3175-3178页

作者：涂成厚李震雷霆李勇男郭文刚魏岱朱辉张双根吕福云 Institute of physics Nankai University Tianjin 300071

A self-similar mode locked fibre laser is studied based on a numerical model. By introducing a dimensionless factor k to characterize the pulse shape, the self-similar pulse evolution, formation and the temporal and spectral shape changes due to the elements in the cavity are investigated throughout the laser cavity. The results show that in the self-similar mode locked fibre laser, self-similar pulse is first formed in the single-mode fibre, which is then amplified in the gain fibre. Gain bandwidth has a small influence on pulse shape, so high energy self-similar pulse can be obtained after amplification. Because net cavity dispersion directly influences the pulse width as well as peak power after compression by a pair of gratings, which can determine the pulse self-similar evolution, it is very important to control the net cavity dispersion to a certain range to obtain self-similar pulses.

关键词： coated conductor buffer layer self-epitaxy CeO2

A Self-Excitation Double Pathway Relaxation Oscillational Model of Rare-Earth-Doped Laser

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Chinese physics Letters 1996年第4期13卷 281-284页

作者： WANG Zhong-he ZHANG Guang-yin Department of physics Nankai UniversityTianjin 300071

A self-excitation double pathway relaxation oscillation mechanism to deal with the seif-pulsing output of up conversion laser with rare-earth ions as the active material is *** reabsorption of the laser signal,which causes self-excitation of system and two-pathway transition of systepi,plays a role of adjusting Q,and causes the oscillation output of laser.A qualitative analysis to the appearance of self-pulsing output of rare-earth-doped laser is given.

关键词： oscillation excitation rare

Damage Spreading in Neural Network with Local Connection and Cycle Stored Patterns

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Chinese physics Letters 1996年第9期13卷 644-647页

作者： JI Dao-yun CHEN Tian-lun Department of physics Nankai UniversityTianjin 300071

The simulation results of damage spreading show the happening of dynamical chaotic-frozen phase transition in a one-dimensional system,a neural network with cycle stored patterns and local *** chaotic phase,the averag... 详细信息

关键词： behavior chaotic dynamical

K and K^＊ Exchange Effects in Lambda Hypernuclei

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Chinese physics Letters 2010年第4期27卷 71-74页

作者：文武申虹 Department of physics Nankai University Tianjin 300071

We study the effects of K and K^＊ exchange between the A hyperon and the nucleon in a A hypernueleus, where the nuclear core is described by a successful relativistic mean-field （RMF） model. In general, K and K^＊ are responsible for strangeness exchange in the one-boson-exchange potential model, which are absent in the RMF calculation. We investigate the contribution of Fock terms derived from K and K^＊ exchange. We use a pseudovector coupling for K exchange, which is found to provide a repulsive potential for the A particle in hypernuclei. Both vector and tensor couplings for K^＊ exchange are taken into account, whose combined effect on the A single-particle energy is found to be small.

关键词： Nuclear physics

Topology of a parity-time symmetric non-Hermitian rhombic lattice

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Chinese physics B 2022年第1期31卷 74-80页

作者： Shumai Zhang Liang Jin Zhi Song School of physics Nankai UniversityTianjin 300071China

We investigate the topological properties of a trimerized parity–time(PT)symmetric non-Hermitian rhombic *** the system is PT-symmetric,the topology is not inherited from the Hermitian lattice;in contrast,the topology can be altered by the non-Hermiticity and depends on the couplings between the *** bulk–boundary correspondence is valid and the Bloch bulk captures the band *** edge states present in the two band gaps and are predicted from the global Zak phase obtained through the Wilson loop *** addition,the anomalous edge states compactly localize within two diamond plaquettes at the boundaries when all bands are flat at the exceptional point of the *** findings reveal the topological properties of the𝒫PT-symmetric non-Hermitian rhombic lattice and shed light on the investigation of multi-band non-Hermitian topological phases.

关键词： topological phase PT symmetry Wilson loop

X-Ray Photoelectron Spectrum Analysis of Yb_(3)C_(60) Compound

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Chinese physics Letters 2001年第5期18卷 656-658页

作者： CAO Xue-Wei SHAO Yue WANG Yu-Fang LAN Guo-Xiang Department of physics Nankai UniversityTianjin 300071

The nominal composition of Yb_(3)C_(60) compound is characterised by means of x-ray photoelectron *** of the divalent state for the Yb cation in the as-grown crystalline Yb_(3)C_(60) is *** exposure to air the Yb_(3)C_(60) compound transforms to an amorphous phase and Yb_(2)O_(3) compound,while the valence state of the Yb cations changes from divalent to trivalent.

关键词： spectroscopy. compound divalent

Photorefractive Spatial Dark-Soliton Stripes in LiNbO_(3):Fe Crystal and Their Application

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Chinese physics Letters 1996年第2期13卷 101-104页

作者： ZHANG Guo-quan LIU Si-min XU Jing-jun ZHANG Guang-yin SUN Qian Department of physics Nankai UniversityTianjin 300071

We observed the photorefractive spatial dark-soliton stripes In LiNbO3:Fe crystal,and demonsirate the planar waveguide property of refractive index proiile induced by these spatial dark-soli ton *** suggest a new moth... 详细信息

关键词： technique waveguide Photorefractive

Tsallis Mapping in Growing Complex Networks with Fitness

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Communications in Theoretical physics 2012年第3期57卷 493-498页

作者：苏桂锋张小兵张一 Department of physics Shanghai Normal University School of physics Nankai University

We introduce Tsallis mapping in Bianconi-Barabgsi （B-B） fitness model of growing networks. This mapping addresses the dynamical behavior of the fitness model within the framework of nonextensive statistics mechanics, which is characterized by a dimensionless nonextensivity parameter q. It is found that this new phenomenological parameter plays an important role in the evolution of networks： the underlying evolving networks may undergo a different phases depending on the q exponents, comparing to the original B-B fitness model, and the corresponding critical transition temperature Tc is also identified.

关键词： growing complex network fitness model Tsallis statistics critical transition

Topological Knots in Quantum Spin Systems

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Chinese physics Letters 2021年第6期38卷 7-12页

作者： X.M.Yang L.Jin Z.Song School of physics Nankai UniversityTianjin 300071China

Knot theory provides a powerful tool for understanding topological matters in biology,chemistry,and *** knot theory is introduced to describe topological phases in a quantum spin *** solvable models with long-range interactions are investigated,and Majorana modes of the quantum spin system are mapped into different knots and *** topological properties of ground states of the spin system are visualized and characterized using crossing and linking numbers,which capture the geometric topologies of knots and *** interactivity of energy bands is *** gapped phases,eigenstate curves are tangled and braided around each other,forming *** gapless phases,the tangled eigenstate curves may form *** findings provide an alternative understanding of phases in the quantum spin system,and provide insights into one-dimension topological phases of matter.

关键词： topological quantum system