Universality of Finite-Size Corrections to Geometrical Entanglement in One-Dimensional Quantum Critical Systems

Xi-Jing Liu,Bing-Quan Hu,Sam Young Cho,Huan-Qiang Zhou,Qian-Qian Shi 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.7

Recently, the finite-size corrections to the geometrical entanglement per lattice site in the spin- 1/2 chain have been numerically shown to scale inversely with system size, and its prefactor b has been suggested to be possibly universal [Q-Q. Shi et al., New J. Phys. 12, 025008 (2010)]. As possible evidence of its universality, the numerical values of the prefactors have been confirmed analytically by using the Affleck-Ludwig boundary entropy with a Neumann boundary condition for a free compactified field [J-M. Stephan et al., Phys. Rev. B 82, 180406(R) (2010)]. However, the Affleck-Ludwig boundary entropy is not unique and does depend on conformally invariant boundary conditions. Here, we show that a unique Affleck-Ludwig boundary entropy corresponding to a finitesize correction to the geometrical entanglement per lattice site exists and show that the ratio of the prefactor b to the corresponding minimum groundstate degeneracy gmin for the Affleck- Ludwig boundary entropy is a constant for any critical region of the spin-1 XXZ system with the single-ion anisotropy, i.e., b/(2 log2 gmin) = −1. Previously studied spin-1/2 systems, including the quantum three-state Potts model, have verified the universal ratio. Hence, the inverse finite-size correction to the geometrical entanglement per lattice site and its prefactor b are universal for one-dimensional critical systems.

Effect of Joint Stiffness on the Stability of Cable-braced Grid Shells

Xi Wang,Ruo-qiang Feng,Gui-rong Yan,Feng-cheng Liu,Wei-jia Xu 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.4

Bolted joints used in cable-braced grid shells are typically semi-rigid joints, and the joint stiffness has a significant effect on the stability of cable-braced grid shells. The effect of joint stiffness on the stability of cable-braced grid shells is studied in this paper. Based on the experimental results of improved bolted joints, finite element models of elliptic paraboloid cable-braced grid shells with bolted joints are established, and spring elements are used to simulate the joint stiffness. The effect of the joint stiffness on the nonlinear buckling load is studied by changing the joint stiffness. The main conclusions are as follows. First, the joint rotational stiffness has a significant effect on the failure mode. When the joint rotational stiffness is small to a certain extent, the failure mode of cable-braced grid shells changes from overall buckling to local buckling. Second, the nonlinear failure mode is similar to the first-order eigenvalue buckling mode and the maximal compression stress distribution. The structural integrity is weakened, and the maximal steel tube compression stress decreases with the decrease of the joint rotational stiffness. The smaller the joint rotational stiffness, the lower the utilization rate of steel strength. The results suggest that the joint stiffness of elliptic paraboloid cable-braced grid shells should not be less than 20% of the rigid joint stiffness.

Optimization of Submerged Fermentation Medium for Matrine Production by Aspergillus terreus, an Endophytic Fungus Harboring Seeds of Sophora flavescens, Using Response Surface Methodology

( Qiang Zhang ),( Yujuan Li ),( Fangxue Xu ),( Mengmeng Zheng ),( Xiaozhi Xi ),( Xuelan Zhang ),( Chunchao Han ) 한국균학회 2017 Mycobiology Vol.45 No.2

Different endophytes isolated from the seeds of Sophora flavescens were tested for their ability to produce matrine production. Response surface methodology (RSM) was applied to optimize the medium components for the endophytic fungus. Results indicated that endophyte Aspergillus terreus had the ability to produce matrine. The single factor tests demonstrated that potato starch was the best carbon source and the combination of peptone and NH₄NO₃ was the optimal nitrogen source for A. terreus. The model of RSM predicted to gain the maximal matrine production at 20.67 μg/L, when the potato starch was 160.68 g/L, peptone was 24.96 g/L and NH₄NO₃ was 2.11 g/L. When cultured in the optimal medium, the matrine yield was an average of 20.63 ± 0.11 μg/L, which was consistent with the model prediction. This study offered an alternative source for the matrine production by endophytic fungus fermentation and may have far-reaching prospect and value.

EMBRYOS OF EARLY CRETACEOUS CHORISTODERA (REPTILIA) FROM THE JEHOL BIOTA IN WESTERN LIAONING, CHINA

Qiang Ji,Shu-an Ji,Junchang Lu,Hailu You,Chong-xi Yuan 한국고생물학회 2006 고생물학회지 Vol.22 No.1

Choristodera는 잘 알려지지 않은 그룹이지만 매우 독특한 해양 파충류로 후기 트라이아스기에서부터 후기 올리고세까지 아시아, 북미, 유럽에 걸쳐 산출된다. 비록 수천 개의 choristodera 표본이 중국 전기 백악기 Jehol biota에서 수집되었지만 바다거북처럼 난태생이였는지 Pachypleurosauria (해양파충류) Keichousaurus hui처럼 태생이었는지 아직 확실하게 밝혀지지 않았다. 우리는 이 논문에서 중국 서부 요녕성의 Jiufotang층에서 산출된 가죽질의 알껍데기가 함께 잘 보존된 Hyphalosaurus baitaigouensis (파충류, Choristodera)를 보고한다. 이것은 Hyphalosaurus baitai-gouensis 같은 choristoderian 파충류가 남중국 Guizhou에서 산출된 후기 트라이아스기 Keichousaurus hui처럼 태생이었을 것임을 지시하는 직접적인 첫 번째 증거다. The Choristodera is a poorly known clade, but very a distinctive group of aquatic reptiles, which has been found from the Late Triassic to the Late Oligocene in Asia, North America and Europe. Although thousands of choristoderian specimens have been collected from the Early Cretaceous non-marine beds in Liaoning, China, no direct evidences have been found to determine whether they were oviparous like sea turtles or viviparous like Keichousaurus hui of Pacbypleurosauria (marine reptiles). Here we report a well-preserved specimen of Hyphalosaurus baitaigouensis with leathery embryonic eggs from the Jiufotang Formation in western Liaoning, China. It provides the first direct evidence to indicate that choristoderian reptiles are most likely viviparous like Late Triassic Keichousaurus hui from Guizhou, Southern China.

The Antiferromagnetic Cross-coupled Spin Ladder: Quantum Fidelity and Tensor Networks Approach

Xi-Hao Chen,Sam Young Cho,Huan-Qiang Zhou,Murray T. Batchelor 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.9

We investigate the phase diagram of the cross-coupled Heisenberg spin ladder with antiferromagnetic couplings. For this model, the results for the existence of the columnar dimer phase, which was predicted on the basis of weak coupling field theory renormalization group arguments, have been conflicting. The numerical work on this model has been based on various approaches, including exact diagonalization, series expansions and density-matrix renormalization group calculations. Using the recently-developed tensor network states and groundstate fidelity approach for quantum spin ladders, we find no evidence for the existence of the columnar dimer phase. We also provide an argument based on the symmetry of the Hamiltonian, which suggests that the phase diagram for antiferromagnetic couplings consists of a single line separating the rung-singlet and the Haldane phases.

Simulation of Nonlinear Behavior of Beam Structures Based on Discrete Element Method

Ruo-qiang Feng,Baochen Zhu,Chunchang Hu,Xi Wang 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.5

In this paper, the discrete element method (DEM) is improved to simulate the strong nonlinear mechanics behavior of beam structures. First, the spring stiff ness of parallel bond model applied to beam structure is deduced using the principle of energy conservation, and the relationship between spring stiff ness and elastic constants is established. Second, the layered beam theory is introduced into the traditional DEM. The yield criteria and the spring stiff ness of contact in yield state are deduced, so that the improved DEM can be used to solve the plastic problem of beam structures. Third, the fracture criterion based on the limit strain of material is defi ned, so that the fracture problem of steel beams can be solved by DEM. Fourth, the force–displacement equations of Hertz model is deduced. Finally, the numerical examples show that the improved DEM can eff ectively solve the problems of large deformation, plasticity, fracture, contact and collision of beam structures.

An Anti-wind Modeling Method of Quadrotor Aircraft and Cascade Controller Design Based on Improved Extended State Observer

Houyin Xi,Dong Zhang,Tao Zhou,Yunxiao Yang,Qiang Wei 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.3

Wind disturbance may significantly reduce the flight control performance of quadrotors when flying. In order to meet high performance flight control requirements, this paper presents a quadrotor anti-wind model (QAWM) and a flight control scheme for quadrotors. The QAWM takes the influence of aerodynamic effects on the propeller, gyroscopic effect and wind disturbance into account. The model can represent more flight states including not only hovering but also flight in windy conditions even maneuver flight. A cascade control schemewith an improved extended state observer (IESO) is adopted to decompose the quadrotor flight control problem into position control loop and attitude control loop. In the attitude control loop, the IESO is used to estimate the unmodeled dynamics, parameter uncertainties and external disturbances, as well as compensate the angular velocity control. In addition, the stability of IESO and the closed loop system are proved. Simulation and experimental results show the effectiveness of the nonlinear quadrotor model and control scheme, and the control scheme can effectively improve the flight performance of quadrotors under wind disturbance even maneuver flight.

" 파 " 자기의구급기상관구식

소해강 중국어문학회 1997 中國語文學誌 Vol.4 No.-

남경방언중적F - V(O)여 V - neg - V(O)

소해강 중국어문학회 1998 中國語文學誌 Vol.5 No.-

Characteristics of Pre-alloyed Powders for Diamond Tools

Luo Xi-Yu,Ma Hong-Qiu,Kuang Xing,Huang Man,Tang Ming-Qiang 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

In this paper, the fundamental attributes, phase composition of three pre-alloyed powders for diamond tools by water atomization were investigated. The density, hardness, bend strength and bending modulus of their hot pressing samples were examined. The results showed that the three pre-alloyed powders have excellent low temperature sintering characteristics. The physical and mechanical properties of the samples were found to be nearly the same as those of fine cobalt powders.