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Table-like magnetocaloric effect and large refrigerant capacity of composite magnetic refrigerants based on LaFe_(11.6)Si_(1.4)H_y alloys

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Journal of Rare Earths 2018年第6期36卷 613-618页

作者： Lingtong Zhou Yongbai Tang Yungui Chen Huaqiang Guo Wenkai Pang Xi Zhao college of Materials Science and engineering Sichuan University

Composite magnetic refrigerants were prepared by physical mixing LaFeSiHalloys with different Curie temperatures(Tc). The phase structures of these LaFeSiHalloys were analyzed by X-ray diffraction(XRD) and the magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The results indicate the experimental magnetic entropy change(-△S)-Tcurve corresponds reasonably with the(-△S)-Tcurve calculated by the linear combination of(-△S)-T curves of the single material. An optimal mixing ratio can make the composite magnetic refrigerant possess a table-like(-△S)-Tcurve which is beneficial to magnetic Ericsson cycle. When three LaFeSiHalloys with different Tare mixed, the full width at half maximum(△T) of(-△S)-T curves is about 48.7 K and the RC is about 177.76 J/kg under a magnetic field change of 2.T. The composite magnetic refrigerants based on LaFeSiHalloys can be promising candidates for near room temperature magnetic refrigeration and the work will be helpful to develop novel composite magnetic refrigerants with table-like MCE and large RC.

关键词： Magnetic refrigeration Magnetocaloric effect Table-like LaFe_(11.6)Si_(1.4)H_y Composite refrigerant Rare earths

A Finite-Time Recurrent Neural Network for Computing Quadratic Minimization with Time-Varying Coefficients

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Chinese Journal of Electronics 2019年第2期28卷 253-258页

作者： XIAO Lin LU Rongbo college of Information Science and engineering Jishou University

This paper proposes a Finite-time Zhang neural network(FTZNN) to solve time-varying quadratic minimization problems. Different from the original Zhang neural network(ZNN) that is specially designed to solve time-varying problems and possesses an exponential convergence property, the proposed neural network exploits a sign-bi-power activation function so that it can achieve the finite-time convergence. In addition, the upper bound of the finite convergence time for the FTZNN model is analytically estimated in theory. For comparative purposes, the original ZNN model is also presented to solve time-varying quadratic minimization problems. Numerical experiments are performed to evaluate and compare the performance of the original ZNN model and the FTZNN model. The results demonstrate that the FTZNN model is a more effective solution model for solving time-varying quadratic minimization problems.

关键词： Recurrent neural network Quadratic minimization Activation function Finite-time convergence Comparative verification

Phase Transition Behavior of LiCr 0.35 Mn0.65O2.under High Pressure by Electrical Conductivity Measurement

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Chinese physics Letters 2010年第3期27卷 236-238页

作者：崔晓岩胡廷静韩永昊高春晓彭刚刘才龙吴宝嘉王月刘鲍任万彬李岩苏宁宁邹广田杜菲陈岗 State Key Laboratory for Superhaxd Materials Jilin University Changchun 130012 college of physics Jilin Normal University Siping 136000 college of physics Jilin University Changchun 130012

The electrical conductivity of powdered LiCr 0.35 Mn0.65O2.is measured under high pressure up to 2..2. GPa in the temperature range 300-413 K by using a diamond anvil cell. It is found that both conductivity and activation enthalpy change discontinuously at 5.36 GPa and 2..66 GPa. In the pressure range 1.10-5.36 GPa, pressure increases the activation enthalpy and reduces the carrier scattering, which finally leads to the conductivity increase. In the pressure ranges 6.32.2..66 GPa and 2..60-2..2. GPa, the activation enthalpy decreases with pressure increasing, which has a positive contribution to electrical conductivity increase. Two pressure-induced structural phase transitions are found by in-situ x-ray diffraction under high pressure, which results in the discontinuous changes of conductivity and activation enthalpy.

关键词： Condensed matter: electrical magnetic and optical Condensed matter: structural mechanical & thermal

UNCONDITIONALLY OPTIMAL ERROR ANALYSIS OF THE SECOND-ORDER BDF FINITE ELEMENT METHOD FOR THE KURAMOTO-TSUZUKI EQUATION

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Journal of Computational Mathematics 2023年第2期41卷 211-223页

作者： Yuan Li Xuewei Cui college of Mathematics and physics Wenzhou UniversityWenzhou 325035China

This paper aims to study a second-order semi-implicit BDF finite element scheme for the Kuramoto-Tsuzuki equations in two dimensional and three dimensional *** proposed scheme is stable and the nonlinear term is linearized by the extrapolation ***,we prove that the error estimate in L^(2.-norm is unconditionally optimal which means that there has not any restriction on the time step and the mesh ***,numerical results are displayed to illustrate our theoretical analysis.

关键词： Kuramoto-Tsuzuki equations BDF scheme Finite element method Optimal error analysi

New γ-soft rotation in the interacting boson model with SU(3) higher-order interactions

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Chinese physics C 2022年第7期46卷 93-102页

作者： Tao Wang college of physics Tonghua Normal UniversityTonghua 134000China

The interacting boson model with S U(3) higher-order interactions offers a new route to enhance our understanding onγ-soft *** this paper, U(5) -like and O(6) -like newγ-softness are observed,in which the corresponding energy levels in the ground and quasi-γbands can be exactly degenerate and have a partial O(5) dynamical *** spherical-likeγ-softness is not related to the classical O(6) dynamical *** transitional behaviors of B(E2. values of the low-lying levels and quadrupole moment of the 2.(+)_(1) state are also ***-likeγ-softness can be used to explain the low-lying spectra and B(E2. values in ^(110)Cd normal states.

关键词： new y-softness SU(3)higher-order interaction SU(3)degenerate point partial O(5)dynamical symmetry

Tailoring the microstructure and mechanical properties of the final Al-Mn foils by different intermediate annealing process

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Journal of Materials Science & Technology 2017年第9期33卷 961-970页

作者： Li Huang Guangjie Huang Yunchang Xin Lingfei Cao Xiaodong Wu Zhihong Jia Qilei Li Qing Liu college of Materials Science and engineering Chongqing University

In this work, two different intermediate annealing processes, single-step annealing（SSA, 530?C/15 h）and two-step annealing（TSA, 450?C/5 h + 530?C/15 h）, were used to tailor microstructure before coldrolling and annealing of the final twin-roll cast Al-Mn foils. The recrystallization behavior and mechanical properties during annealing of severely cold-rolled foils were systematically studied. Our results show that discontinuous recrystallization occurs in SSA-foils during annealing at 150–310?C, in contrast with continuous recrystallization in TSA-foils. The continuous recrystallization develops much finer grains（;.35 μm） in the TSA-foils than those by discontinuous recrystallization in the SSA-foils（;4.7 μm）. The texture components in cold-rolled TSA-foils hardly change（retained rolling-textures） after continuous recrystallization, while those in the cold-rolled SSA-foils mainly transform into a strong cube component{001} after discontinuous recrystallization. Finally, a maximized elongation to fracture of;3.9%was achieved in the TSA-foil, much higher than that of the SSA-counterparts,;.3%. The relationships between the microstructure and mechanical properties were discussed.

关键词： Al-Mn alloys Foil Annealing Recrystallization mechanism Size effect Mechanical property

Load history-based model for prestressed concrete beam damage evaluation

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Earthquake engineering and engineering Vibration 2007年第4期6卷 383-390页

作者：袁建力王仪钱仲慧 college of Architecture Science and engineering Yangzhou University

The residual capability of a damaged structure to resist further load is essential in optimal seismic design and post-earthquake strengthening. An experimental study on the hysteretic characteristics of prestressed concrete frame beams under different loading histories was performed to explore the influence of load history on energy dissipation and failure characteristics of the member. Based on the test results, the failure of the beam is defined, and the relationship between the failure moment under cyclic load and from the skeleton curve is formulated. Finally, based on displacement and energy dissipation, a model for prestressed concrete beam damage-failure evaluation is developed. In this model, the effect of deformation level, cumulative dissipated energy, and loading history on prestressed concrete beam damage-failure is incorporated, thus it is applicable to stochastic earthquake forces.

关键词： prestressed concrete earthquake force load history energy dissipation damage-failure evaluation

Perturbation to Lie Symmetry and Adiabatic Invariants for General Holonomic Mechanical Systems

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Communications in Theoretical physics 2007年第7期48卷 19-22页

作者： DING Ning FANG Jian-Hui WANG Peng ZHANG Xiao-Ni college of physics Science and Technology,China University of Petroleum,Dongying 2.7061,China college of physics Science and Technology China University of Petroleum

Based on the concept of adiabatic invariant,the perturbation to the Lie symmetry and adiabatic invariantsfor general holonomic mechanical systems are *** exact invariants induced directly from the Lie symmetryof the system without perturbation are *** perturbation to the Lie symmetry is discussed and the adiabaticinvariants that have the different form from that in[***.55(2.06)32.6(in Chinese)]of the perturbedsystem,are obtained.

关键词： Lie symmetry perturbation adiabatic invariant general holonomic mechanical’system

Fabrication and Characterization of Porous Sintered Ti—Ag Compacts for Biomedical Application Purpose

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Journal of Materials Science & Technology 2013年第4期29卷 330-338页

作者： Legan Hou Li Li Yufeng Zheng Center for Biomedical Materials and engineering Harbin Engineering University Department of Materials Science and engineering College of EngineeringPeking University

Porous sintered Ti-Ag compacts with different Ag content were fabricated by powder metallurgy. The associated hydrothermal treatment and the effect on the apatite formation were studied. The results suggested that TiO was generated under the condition of low vacuum （1 ×10^-2.Pa） during the process of burning out the spacer-holding particles. After hydrothermal treatment, a sub-microscale porous layer was formed at the pore wall surface of the samples. The apatite-inducing ability of hydrothermal treated porous sintered Ti-Ag compacts with different Ag content was evaluated in modified simulated body fluid （SBF）. And the results proved that there is a clear correlation between the apatite-inducing ability and Ag content. The higher Ag content in porous leads to the decrease of Na＋ ions and basic hydroxyl （OH）b amount, resulting in the decline of apatite-inducing ability in the first stage. However, their apatite-inducing ability was not significantly different from that of Ti after two weeks SBF immersing. Hence, the ionic activity should restore with the processing of SBF soaking, as the saturation of Ag effect.

关键词： Porous sintered Ti-Ag compacts Ag content Hydrothermal treatment Apatite-inducing ability