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Feasibility study of a practical causal rate-independent damping device for the improved performance of seismic isolated structures

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ENGINEERING STRUCTURES 2023年第PartB期275卷 1页

作者： Wu, Zhanzhan Liu, Wei Ikago, Kohju Tohoku Univ Grad Sch Engn Sendai 9808572 Japan Tohoku Univ Int Res Inst Disaster Sci Sendai 9808572 Japan Tohoku Univ Int Res Inst Disaster Sci 468-1 Aramaki Aza AobaAoba Ku Sendai 9808572 Japan

When rate-independent linear damping (RILD) is incorporated into a base-isolated structure, it achieves a similar response displacement reduction effect with significantly lower floor response acceleration compared with linear viscous damping (LVD) with the same loss factor. To address the undesirable stiffness added to an isolation layer when we adopt a mechanical device comprising a few branches of a spring-dashpot link to realize RILD, this study proposes canceling the undesirable isolator stiffness by adding an inerter element and reducing the isolator stiffness. A heuristic optimization method was developed to design the proposed mechanical device to mimic the behavior of RILD. A parametric survey on the optimal designs of the device suggests that the three branches of the spring-dashpot link work best in terms of practicality and feasibility. Seismic control performance was assessed using a 10-story base-isolated building mounted on linear and nonlinear isolation systems. Analyses of linear systems revealed that the proposed device achieved lower inter-story drifts and approximately 40% reduction in floor response acceleration with a 4% increase in isolator displacement compared with the LVD when subjected to high-frequency ground motions. Analyses of the nonlinear systems showed that the displacement control performance of the proposed model was slightly compromised when subjected to ground motions dominated by low-frequency components, thereby identifying a further challenge in developing a causal RILD device for nonlinear structures.

关键词： Rate-independent linear damping Maxwell-Wiechert model Inerter Low-frequency structure global optimization algorithm

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Almost perfect quantum state transfer on isotropic and anisotropic Heisenberg spin chains with tailored site dependent exchange couplings

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PHYSICS LETTERS A 2022年 449卷

作者： Serra, Pablo Ferron, Alejandro Osenda, Omar Univ Nacl Cordoba Fac Matemat Astron Fis & Computac CONICET Inst Fis Enrique Gaviola Av Medina Allende S-NCiudad UnivCP X5000HUA Cordoba Argentina Univ Nacl Nordeste Inst Modelado & Innovac Tecnol CONICET UNNE Ave Libertad 5400W3404AAS Corrientes Argentina Univ Nacl Nordeste Fac Ciencias Exactas Nat & Agrimensura Ave Libertad 5400W3404AAS Corrientes Argentina

Spin chains with site dependent exchange coefficients can achieve near perfect quantum state transfer for Hamiltonians with nearest neighbors XXZ type interactions without external control. The strength of the interactions is obtained using a global optimization method, which can be employed without assuming a particular relationship between the arrival time and the strength of the interactions. This relationship arises naturally when data collapse techniques are used to analyze the results of the optimization method. The arrival times achievable are competitive with respect to those obtained by other methods, for chains of moderate length. The stability of the resulting spin chains against static perturbations is also studied. The differences in the dynamical behavior between the isotropic and anisotropic spin chains are analyzed for some particular cases.(C) 2022 Elsevier B.V. All rights reserved.

关键词： Quantum spin chains global optimization algorithm Almost perfect quantum state transfer Control

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Diffractive optical element design based on vector diffraction theory and improved PSO-SA algorithm

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OPTICAL ENGINEERING 2023年第2期62卷 025103-025103页

作者： Yan, Yu Fan, Zhentao Sun, Guofang Tian, Kehan Zhejiang Univ Sci & Technol Hangzhou Peoples R China Jiaxing Yuguang Photoelect Technol Co Ltd Jiaxing Peoples R China Beijing Yuguang Technol Dev Co Beijing Peoples R China

The existence of the beam vector effect requires rigorous electromagnetic computational methods for the optimization of subwavelength diffractive optical elements (DOEs). To design DOEs with high performance, we proposed an optimization strategy combining a global optimization algorithm with the finite difference time domain (FDTD) method. First, scalar initial solutions are obtained by the Gerchberg-Saxton algorithm. Then, regarding the diffraction efficiency, the uniformity error and figure of merit are calculated by FDTD as evaluation functions, and the optimization of the initial solutions is implemented by improved particle swarm optimization and continues with the simulated annealing algorithm. After several numerical simulations, the analysis results confirm the robustness of the algorithm and the reduction of the computational cost. The experimental data demonstrate that the correlation of diffraction energy orders between the simulated design and fabricated sample are above 85%. This method efficiently improves the DOEs design.

关键词： diffraction optical elements finite difference time domain global optimization algorithm beam splitter

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Comparison of Regional Winter Wheat Mapping Results from Different Similarity Measurement Indicators of NDVI Time Series and Their Optimized Thresholds

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REMOTE SENSING 2021年第6期13卷 1162-1162页

作者： Li, Fangjie Ren, Jianqiang Wu, Shangrong Zhao, Hongwei Zhang, Ningdan Chinese Acad Agr Sci Inst Agr Resources & Reg Planning Beijing 100081 Peoples R China Key Lab Agr Remote Sensing Minist Agr & Rural Affairs Beijing 100081 Peoples R China

Generally, there is an inconsistency between the total regional crop area that was obtained from remote sensing technology and the official statistical data on crop areas. When performing scale conversion and data aggregation of remote sensing-based crop mapping results from different administrative scales, it is difficult to obtain accurate crop planting area that match crop area statistics well at the corresponding administrative level. This problem affects the application of remote sensing-based crop mapping results. In order to solve the above problem, taking Fucheng County of Hebei Province in the Huanghuaihai Plain of China as the study area, based on the Sentinel-2 normalized difference vegetation index (NDVI) time series data covering the whole winter wheat growth period, the statistical data of the regional winter wheat planting area were regarded as reference for the winter wheat planting area extracted by remote sensing, and a new method for winter wheat mapping that is based on similarity measurement indicators and their threshold optimizations (WWM-SMITO) was proposed with the support of the shuffled complex evolution-University of Arizona (SCE-UA) global optimization algorithm. The accuracy of the regional winter wheat mapping results was verified, and accuracy comparisons with different similarity indicators were carried out. The results showed that the total area accuracy of the winter wheat area extraction by the proposed method reached over 99.99%, which achieved a consistency that was between the regional remote sensing-based winter wheat planting area and the statistical data on the winter wheat planting area. The crop recognition accuracy also reached a high level, which showed that the proposed method was effective and feasible. Moreover, in the accuracy comparison of crop mapping results based on six different similarity indicators, the winter wheat distribution that was extracted by root mean square error (RMSE) had the best recognition accur

关键词： crop mapping similarity crop area statistical data total amount control global optimization algorithm

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Transformation rule-based molecular evolution for automatic gasoline molecule design

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CHEMICAL ENGINEERING SCIENCE 2022年 263卷

作者： Cai, Guangqing Liu, Zhefu Zhang, Linzhou China Univ Petr Petr Mol Engn Ctr PMEC State Key Lab Heavy Oil Proc Beijing 102249 Peoples R China Chinese Acad Sci Quanzhou Inst Equipment Mfg Computat Intelligence & Ind Big Data Grp Luoshan St 166 Jinjiang City 362216 Fujian Peoples R China

Automatic molecular design on computers is an emerging technology for the determination of optimal fuel molecules. We developed a computer-aided molecular design framework through a transformation rule-based molecular evolution method. The reaction rule was used as the elementary step to change the molecular structure. A molecule can achieve structural variation continuously using a series of reaction rules. The finding of the optimal molecule can be seen as the evolution of structure in the chemical space, which was guided by using a global optimization algorithm to select the best reaction routine. We showed that the optimized molecule is independent of the input initial structure, proving the robustness of the method. We then applied the method to design gasoline molecules for motor and aviation gasoline. The designed molecules can not only serve as competitive candidate components for high-quality gasoline, but also accelerate the synthesis rate of new molecules in the laboratory. (C) 2022 Elsevier Ltd. All rights reserved.

关键词： Molecular design Transformation rule Structural variation global optimization algorithm Gasoline molecule

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A study on a representative heat source model for simulating laser welding for liquid hydrogen storage containers

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MARINE STRUCTURES 2022年 86卷

作者： Pyo, Changmin Kim, Jaewoong Kim, Younghyun Kim, Munsung Korea Inst Ind Technol Gwangju 61012 South Korea Korea Corp Dassault Syst Seoul 06164 South Korea

Laser welding enhances the productivity with high speed, and minimizes thermoelastic distortion with a concentrated heat source for a narrow area over a short period of time. With these strengths various industries such as the automobile, aviation, and shipbuilding adopt that. However welding distortion is still one of principal problems, simulation of distortion and corresponding design are very important for applying that technology. Naturally accurate laser welding heat source model is needed, but there is not representative heat source model which can cover diverse types of models. This study proposes a multi-layered heat source model as a representative model, and develops a welding heat source that complies with welding conditions by comparing it to the bead-on-plate welding experiment on 304L stainless steel, a material used for cryogenic purposes with liquid hydrogen condition. To derive a welding heat source, a parametric study was used as it was able to identify an appropriate solution by changing the parameter values constituting the heat source for finite element analysis, where the physical properties for each temperature were applied. For this process optimization method was applied, and the objective function and constraints were defined based on the value of temperature through simulation, also a global optimization algorithm was adopted. In this study, we suggest a representative model that can be used under most welding conditions;this is a method that can be of great help in future welding distortion analyses and can be used in a design that can tolerate distortion.

关键词： Representative welding heat source model Multi-layered heat source model global optimization algorithm Liquid hydrogen Fiber laser welding

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optimization of Hydrogen Distribution Network Considering Pressure and heat recovery

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Energy Procedia 2015年 75卷 1147-1152页

作者： Ruifeng Dong Yunsong Yu Zaoxiao Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 PR China School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an 710049 PR China

Hydrogen is an important resource in chemical processes. In the hydrogen network, many units are operating at high temperature and pressure, which leads to a large energy change of hydrogen streams. However, the recovery of heat and work in the hydrogen flows has seldom been studied together with the optimization of hydrogen network. It is obviously that the reuse of heat and work energy will raise the effective utilization rate of energy. The recovery of heat could be realized by heat exchangers. The recovery of work will be realized by rotary work exchangers, which are composed of several compressors and turbines with the same shaft. A state space superstructure is adopted to handle all the variables. The mathematical model is built based on exergoeconomic analysis considering both energy and economic factors. The optimization problem will be a mixed integer nonlinear programming (MINLP) problem. The existing algorithms will be improved. A typical refinery hydrogen network is studied as an example. The state space superstructure, exergoeconomic analysis and proposed algorithm could solve the problem competently. The consideration of pressure and heat recovery could reduce the energy consumption and economic cost simultaneously.

关键词： Hydrogen network Heat recovery Work recovery Exergoeconomic analysis global optimization algorithm

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Model parameter estimation for Channelrhodopsin-2 light gated ion channels

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BMC Neuroscience 2011年第1期12卷 1-2页

作者： Shivakeshavan G Ratnadurai Pramod P Khargonekar Paul R Carney Sachin S Talathi Department of Electrical and Computer Engineering University of Florida Gainesville Florida 32611 USA Department of Biomedical Engineering University of Florida Gainesville Florida 32611 USA Department of Pedriatics University of Florida Gainesville Florida 32611 USA

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Structure and Bonding of Titanium Alanate

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CHEMISTRYSELECT 2024年第40期9卷

作者： Wu, Junlin Ma, Li Liu, Jiang Chen, Hongshan Chen, Xiaofeng Zhang, Sa Wang, Xiaoxia Chengdu Univ Technol Coll Math & Phys Chengdu 610059 Peoples R China Northwest Normal Univ Coll Phys & Elect Engn Lanzhou 730070 Peoples R China

Titanium alanate Ti(AlH4)4 is a candidate material for high-density hydrogen storage that thus far has been scarcely investigated. This study determines the low energy structures of Ti(AlH4)4 by adopting a global optimization algorithm combined with density functional theories, and systematically compares their stabilities, electronic structures, and bonding properties with Mg(AlH4)2 and Ca(AlH4)2. Compared to other compounds, Ti(AlH4)4 is less stable and the Ti-H bond is of covalent nature with strong polarities. The covalent Ti-H interaction can weaken the Al-H bonds. Because both the ionic and covalent interactions of the Al-H bonds are the weakest in Ti(AlH4)4, it is favorable for the desorption of hydrogen. In this study, we determine the low energy structures of Ti(AlH4)4 and investigate their stabilities, electronic structures, and bonding properties. Ti(AlH4)4 is less stable and the covalent Ti-H interaction can weaken the Al-H bonds. Because both the ionic and covalent interactions of the Al-H bonds are the weakest in Ti(AlH4)4, it may be a promising hydrogen storage material. image

关键词： Titanium alanate Bonding nature global optimization algorithm Density functional calculations

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A real time multi-objective optimization Guided-MPC strategy for power-split hybrid electric bus based on velocity prediction

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ENERGY 2023年第1期276卷

作者： Yang, Dongpo Liu, Tong Song, Dafeng Zhang, Xuanming Zeng, Xiaohua Jilin Univ State Key Lab Automot Simulat & Control Changchun 130025 Peoples R China

Considering the frequent acceleration and deceleration of bus vehicles, the working conditions are complex, efficiency-oriented power-split hybrid electric bus (PSHEB) typically require frequent shifting to stay in high-efficiency areas, driving comfort and fuel economy may be affected. Therefore, to achieve a good balance be-tween overall efficiency and shifting stability, the study proposes a Real time Multi-objective optimization Guided-MPC strategy (RMGMPC) for PSHEB based on velocity prediction. Firstly, considering the different driving habits of drivers, combining with multi-source data fusion technology, a vehicle speed prediction controller is established;secondly, based on global optimization algorithm and multi-source data fusion tech-nology, a SOC reference generator is designed, which will determine the SOC guidance at predicted vehicle speed time domain online;then, to coordinate fuel efficiency, shifting stability and online optimization control real-time, the novel RMGMPC based on the direct multiple shooting method and sequential quadratic program-ming algorithm for PSHEB is proposed;finally, to avoid experience value of uncertain weight coefficient affecting the MPC, a weighted method of objective function with orientation is proposed. To verify the effectiveness of RMGMPC, the fuel economy reaches 98.41% of the global optimum;the shifting times are improved by 12.5%;Compared with MPC-DP, the calculation time is improved by 93.97%;And HIL test was carried out to further verify the real-time performance of the algorithm. The results manifest the excellent performance of the proposed RMGMPC.

关键词： Power-split hybrid electric bus MPC global optimization algorithm Direct multiple shooting method HIL test

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