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Symplectic analysis for elastic wave propagation in two-dimensional cellular structures

Acta Mechanica Sinica 2010年第5期26卷 711-720页

作者： Xiu-Hui Hou zi-Chen Deng jia-Xi Zhou Tie-Quan Liu Department of Engineering Mechanics Northwestern Polytechnical University Xi'an 710072 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China

On the basis of the finite element analysis, the elastic wave propagation in cellular structures is investigated using the symplectic algorithm. The variation principle is first applied to obtain the dual variables and the wave propagation problem is then transformed into two-dimensional （2D） symplectic eigenvalue problems, where the extended Wittrick-Williams algorithm is used to ensure that no phase propagation eigenvalues are missed during computation. Three typical cellular structures, square, triangle and hexagon, are introduced to illustrate the unique feature of the symplectic algorithm in higher-frequency calculation, which is due to the conserved properties of the structure-preserving symplectic algorithm. On the basis of the dispersion relations and phase constant surface analysis, the band structure is shown to be insensitive to the material type at lower frequencies, however, much more related at higher frequencies. This paper also demonstrates how the boundary conditions adopted in the finite element modeling process and the structures＇ configurations affect the band structures. The hexagonal cells are demonstrated to be more efficient for sound insulation at higher frequencies, while the triangular cells are preferred at lower frequencies. No complete band gaps are observed for the square cells with fixed-end boundary conditions. The analysis of phase constant surfaces guides the design of 2D cellular structures where waves at certain frequencies do not propagate in specified directions. The findings from the present study will provide invaluable guidelines for the future application of cellular structures in sound insulation.

关键词： Cellular structures Symplectic analysis Dispersion relation - Phase constant surface Sound insulation

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A New Nor-neolignan from Cremanthodium ellisii

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Chinese Chemical Letters 1999年第2期10卷 129-130页

作者： su, BN Zhu, QX jia, ZJ Lanzhou Univ Dept Chem Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China

A new nor-neolignan, named ellisinin A (1), has been isolated from the traditional Tibetan medicinal plants of Cremanthodium ellisii. Its structure has been determined on the basis of spectroscopic evidence, especiall... 详细信息

关键词： Cremanthodium ellisii compositae nor-neolignan ellisinin A

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A New Lignan Glucoside from Lancea tibetica

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Chinese Chemical Letters 1999年第1期10卷 37-38页

作者： su, BN Yuan, CS jia, ZJ Lanzhou Univ Natl Lab Appl Organ Chem Dept Chem Lanzhou 730000 Peoples R China

A new 7-9'-monoepoxy tetrahydrofuran type lignan glucoside with the cis-relationship of H-7 and H-8, named tibeticoside A 1, was isolated from the medicinal whole plants of Lancea tibetica. Its structure was elucidate... 详细信息

关键词： Lancea tibetica scrophulariaceae tibeticoside A

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Forecast of cosmological constraints with superluminous supernovae from the Chinese Space Station Telescope

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 128-138页

作者： Xuan-Dong jia jian-Ping Hu Fa-Yin Wang zi-Gao Dai School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210093China Department of Astronomy University of Science and Technology of ChinaHefei 230026China

superluminous supernovae(SLSNe)are a class of intense celestial events that can be standardized for measuring cosmological parameters,bridging the gap between type Ia supernovae and the cosmic microwave *** this work,we discuss the cosmological applications of SLSNe from the Chinese Space Station Telescope(CSST).Our estimation suggests that SLSNe rate is biased tracing the cosmic star formation rate,exhibiting a factor of(1+z)^(1.2).We futher predict that CSST is poised to observe~360 SLSNe in the 10 square degrees ultra-deep field survey within a span of 2.5 years.A stringent constraint on cosmological parameters can be derived from their peak-color *** is anticipated to uncover a substantial number of SLSNe,contributing to a deeper understanding of their central engines and shedding light on the nature of dark energy at high redshifts.

关键词： supernovae cosmology cosmological constant

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Association between the level of CD4^+T lymphocyte microRNA-155 and coronary artery disease in patients with unstable angina pectoris

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Journal of Geriatric Cardiology 2018年第10期15卷 611-617页

作者： zi-Liang WE Hai-Li LU Qiang su Lang Li Department of Cardiology the First Affiliated Hospital of Guangxi Medical UniversityGuangxi Cardiovascular InstituteNanningGuangxiChina Department of Orthodontics the Affiliated Dental Hospitdl of Guangxi Medical UniversityNanningCruangxiChina

Objective To study the association between the expression of microRNA-155(miRNA-155)in peripheral blood CD4^+T lymphocytes and the level of semrn interferon-7(IFN-7)concentration and the severity of coronary artery disease (CAD).Methods After coronary angiography,252patients with suspected unstable angina pectoris (UAP)were divided into the UAP group (128patients with CAD confirmed by angiography)and the control group (124patients without CAD confirmed by angiography).Fresh peripheral blood was extracted 16-24h before coronary angiography,CD4^+T lymphocytes was tested using immunomagnetic beads,the expression ofmiRNA-155was tested using quantitative PCR and the expression of IFN-7was tested using enzyme-linked immunosorbent assay (ELISA).According to the results of angiography,Gensini score of coronary artery lesions was ***,we also analysis the association between the level of miRNA-155in peripheral blood CD4^+T lymphocytes,the level of serum IFN-γand Gensini score of coronary *** The levels ofmiRNA-155(0.49±0.08vs.0.23±0.09)and IFN-7(227.58±26.01vs.141.23±17.89)in the UAP group were significantly higher than that of the control group,the difference was statistically *** level of miRNA-155and IFN-γwere positively correlated with Gensini score of CAD (r =0.534,r =0.713,respectively,all P <0.05).The level of miRNA-155was positively correlated with the level of IFN-γ,(r =0.686,P <0.05).Conclusions The level of miRNA-155in peripheral blood CD4^+T lymphocytes and the level of IFN-γ are closely correlated with the severity of CAD.

关键词： CD4^+T lymphocyte Coronary artery disease IFN-γ MicroRNA-155

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Stock Market Index Prediction Using Deep Neural Network Ensemble 36

Stock Market Index Prediction Using Deep Neural Network Ense...

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第36届中国控制会议

作者： Bing Yang zi-jia Gong Wenqi Yang School of Mathematics and Statistics Shandong University School of Mathematics Shandong University

ISBN: (纸本)9781538629185

In this paper,we put forward deep neural network ensemble to model and predict Chinese stock market index（including Shanghai composite index and SZSE component index）,based on the input indices of recent days.A set of component networks are trained by historical data for this task,where Backpropagation and Adam algorithm are used to train each network *** approach combines these component networks to generate ensemble,which reduces the generalization *** of test examples are predicted with the model,and the trend predictions is calculated based on the predicted ***,relative errors between actual indices and predicted indices,as well as accuracy of trend predictions are computed to measure the performance of *** turns out that the model proposed in this paper can partially model and predict the Chinese stock *** accuracy of trend predictions of the daily barycenter,high,low are 71.34%,74.15%,74.15%respectively for Shanghai composite index and 75.95%,73.95%,72.34%respectively for SZSE component *** the predictions on close are unsatisfactory.

关键词： neural network machine learning ensemble learning stock index time series forecasting

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Double effects of recrystallization behavior on grain morphology evolution and mechanical properties of Al/Mg/Al composite plate by hard plate rolling

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Progress in Natural Science:Materials International 2024年第5期34卷 1029-1038页

作者： jia Yang Zhang Feng Li Fu Wei Kang zi Yi Wang Lu sun School of Materials Science and Chemical Engineering Harbin University of Science and Technology Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology Heilongjiang Provincial Key Laboratory of Light Metal Materials Modification & Green Forming Technology Harbin University of Science and Technology

Enhancing the bonding strength, optimizing the microstructure and refining the properties represent effective strategies for the fabrication of heterogeneous composite plates. In this study, composite plates of Al/Mg/Al were fabricated through hard plate rolling(HPR) with a reduction in rolling ranging from 40 % to 80 %. The research primarily concentrates on the substrate in the influence of rolling dynamic recrystallization(DRX) behavior on the grain morphology evolution and mechanical properties of AZ31 magnesium alloy sheets during the process. The findings indicate that at a compression amount of 60 %, the composite plate exhibits an ultimate tensile strength(UTS), a maximum elongation(EL) of 12.5 %, and improved interface bonding. Comparative analysis reveals the occurrence of DRX on the Mg side, resulting in the formation of small DRXed grains being generated. With an increase in reduction, DRX is facilitated, leading to an initial rise and subsequent decline in the proportion of DRXed grains. The proliferation of fine grains hinder dislocation movement, thereby reinforcing composite ***, an elevation in the degree of recrystallization enhances the initiation of non-basal slip and enhances the plasticity of sheet metal. This study offers valuable scientific guidance and technical assistance for the production of forming high-quality Mg–Al composite plates.

关键词： Al/Mg/Al Composite plate Dynamic recrystallization Hard plate rolling Mechanical properties

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THERMODYNAMIC CALCULATION OF INTERFACE REACTIONS BETWEEN TITANIUM MELT AND SPECIAL MOLD MATERIALS

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中国有色金属学会会刊：英文版 1999年第2期9卷 14-18页

作者： jia, Jun Ding, Hongsheng Guo, Jingjie su, Yanqing Harbin Inst of Technology Harbin China

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｉｔａｎｉｕｍｃａｓｔｉｎｇｓｈａｖｅｂｅｎｗｉｄｅｌｙａｐｐｌｉｅｄｉｎｍａｎｙｒｅｇｉｏｎｓｓｕｃｈａｓａｅｒｏｎａｕｔｉｃｓ，ａｅｒｏｓｐａｃｅａｎｄｓｏｆｏｒｔｈ．Ｂｕｔｔｈｅｄｒ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｉｔａｎｉｕｍｃａｓｔｉｎｇｓｈａｖｅｂｅｎｗｉｄｅｌｙａｐｐｌｉｅｄｉｎｍａｎｙｒｅｇｉｏｎｓｓｕｃｈａｓａｅｒｏｎａｕｔｉｃｓ，ａｅｒｏｓｐａｃｅａｎｄｓｏｆｏｒｔｈ．Ｂｕｔｔｈｅｄｒａｗｂａｃｋｏｆｔｈｅｈｉｇｈｒｅ...

关键词： titaniuminterface reactionGibbs free energymoldrefractory materials

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Biorthogonal quantum criticality in non-Hermitian many-body systems

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Frontiers of physics 2022年第3期17卷 53-61页

作者： Gaoyong sun jia-Chen Tang su-Peng Kou College of Science Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Aerospace Information Materials and Physics(Nanjing University of Aeronautics and Astronautics) MIITNanjing 211106China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China

We develop the perturbation theory of the fidelity susceptibility in biorthogonal bases for arbitrary interacting non-Hermitian many-body systems with real eigenvalues. The quantum criticality in the non-Hermitian transverse field Ising chain is investigated by the second derivative of the ground-state energy and the ground-state fidelity susceptibility. We show that the system undergoes a second-order phase transition with the Ising universal class by numerically computing the critical points and the critical exponents from the finite-size scaling theory. Interestingly, our results indicate that the biorthogonal quantum phase transitions are described by the biorthogonal fidelity susceptibility instead of the conventional fidelity susceptibility.

关键词： biorthogonal quantum criticality non-Hermitian systems fidelity susceptibility

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TWO INNOVATIVE COALITION FORMATION MODELS FOR DYNAMIC TASK ALLOCATION IN DISASTER RESCUES

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Journal of Systems Science and Systems Engineering 2018年第2期27卷 215-230页

作者： Xing su YuechenWang Xibin jia Limin Guo Zhiming Ding Faculty of Information Beijing University of Technology Beijing 100124 China

This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available agents, it is hard for the single-objective and single （task）-to-single （agent） task allocation approaches to handle task allocation in such circumstances. To this end, two multi-objective coalition formation for task allocation models are proposed for disaster rescues in this paper. First, through coalition formation, the proposed models enable agents to cooperatively perform complex tasks that cannot be completed by single agent. In addition, through adjusting the weights of multiple task allocation objectives, the proposed models can employ the linear programming to generate more adaptive task allocation plans, which can satisfy different task allocation requirements in disaster rescue. Finally, through employing the multi-stage task allocation mechanism of the dynamic programming, the proposed models can handle the dynamics of tasks and agents in disaster environments. Experimental results indicate that the proposed models have good performance on coalition formation for task allocation in disaster environments, which can generate suitable task allocation plans according to various objectives of task allocation.

关键词： Disaster rescues multi-objective linear programming cooperative agents multi-stage taskallocation

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