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Temperature Control Based on Fuzzy Logic Two-degree-of-freedom Smith Internal Model

Instrumentation 2020年第2期7卷 1-8页

作者： WANG Zhigang HE Meng Tianjin Key Laboratory for Advanced Mechanical System Design and Intelligent Control Tianjin University of TechnologyTianjin 300384China National Demonstration Centre for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China

According to the characteristics of the large time delay,nonlinearity and the great inertia of temperature control system in biomass pyrolysis reactor,a two-degree-of-freedom Smith internal model controller based on fuzzy control is ***,the mathematical model of the temperature control system is established by using the step response method,and then the two-degree-of-freedom Smith internal model controller is designed,and the good tracking performance and disturbance suppression performance can be obtained by designing the set value tracking controller and interference rejection ***,the fuzzy control algorithm is used to realize the on-line tuning of the control parameters of the two-degree-of-freedom Smith internal model *** simulation results show that,compared with the traditional internal model control,fuzzy internal model PID control and two-degree-of-freedom Smith internal model control,the algorithm proposed in this paper improves the influence of lag time on the control system,realizes the separation control of set point tracking and anti-jamming performance and the self-tuning of control parameters,and improves the control performance of the system.

关键词： Smith Predictive Controller Internal Model Control Two Degrees of Freedom Fuzzy Control Algorithm

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TS-ENAS:Two-Stage Evolution for Cell-based Network Architecture Search

arXiv

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arXiv 2023年

作者： Zou, Juan Wu, Shenghong Xia, Yizhang Jiang, Weiwei Wu, Zeping Zheng, Jinhua Engineering Research Center of Hunan Province for Optimization and Security of Intelligent System Key Laboratory of Intelligent Computing and Information Processing Ministry of Education of China Key Laboratory of Hunan Province for Internet of Things and Information Security Xiangtan University Hunan Province Xiangtan411105 China The College of Aerospace Science and Engineering National University of Defense Technology Hunan Changsha410073 China

Neural network architecture search provides a solution to the automatic design of network structures. However, it is difficult to search the whole network architecture directly. Although using stacked cells to search neural network architectures is an effective way to reduce the complexity of searching, these methods do not able find the global optimal neural network structure since the number of layers, cells and connection methods is fixed. In this paper, we propose a Two-Stage Evolution for cell-based Network Architecture Search(TS-ENAS), including one-stage searching based on stacked cells and second-stage adjusting these cells. In our algorithm, a new cell-based search space and an effective two-stage encoding method are designed to represent cells and neural network structures. In addition, a cell-based weight inheritance strategy is designed to initialize the weight of the network, which significantly reduces the running time of the algorithm. The proposed methods are extensively tested and compared on four image classification dataset, Fashion-MNIST, CIFAR10, CIFAR100 and ImageNet and compared with 22 state-of-the-art algorithms including hand-designed networks and NAS networks. The experimental results show that TS-ENAS can more effectively find the neural network architecture with comparative performance. Copyright © 2023, The Authors. All rights reserved.

关键词： Image classification

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Vibration Absorption Efficiency and Higher Branches Elimination of Variable-Stiffness Nonlinear Energy Sink

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Journal of Harbin Institute of technology(New Series) 2020年第1期27卷 76-84页

作者： Rui Zhong Jian’en Chen Weimin Ge Jun Liu Xiaofeng Wang Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China

Vibration absorption efficiency of a variable⁃stiffness nonlinear energy sink(NES)was investigated when the main oscillator was subjected to harmonic and impulse *** slow flow equations of the coupled system were derived by using the complexification⁃averaging method,and the nonlinear equations which describe the steady⁃state response were *** the harmonic excitation force increased,the system which comprises constant⁃stiffness NES generated higher branch responses,greatly reducing the vibration absorption *** influence of nonlinear stiffness on the responses of the system was *** show that,with the increase of harmonic exciting force,a reduction of NES stiffness can eliminate the higher branch responses and even the frequency band of strongly modulated *** vibration absorption efficiency of variable⁃stiffness NES attached to the linear oscillator for different amplitudes of impulse excitation was *** show that the proper reduction of nonlinear stiffness under increasing impulse excitation can greatly increase the vibration absorption efficiency of NES,and the variable⁃stiffness design can effectively mitigate the negative influences of the increase of the excitation amplitude on the efficiency of constant⁃stiffness NES.

关键词： nonlinear energy sink efficiency variable⁃stiffness vibration suppression higher branch

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A high-performance and endurable SSD cache for parity-based RAID

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Frontiers of Computer science 2019年第1期13卷 16-34页

作者： Chu LI Dan FENG Yu HUA Fang WANG Wuhan National Lab for Optoelectronics Key Laboratory of Information Storage System(School of Computer Science and TechnologyHuazhong University of Science and Technology) Ministry of Education of ChinaWuhan 430074China

Solid-state drives (SSDs)have been widely used as caching tier for disk-based RAID systems to speed up dataintensive ***,traditional cache schemes fail to effectively boost the parity-based RAID storage sys- tems (e.g.,RAID-5/6),which have poor random write performance due to the small-write ***'s worse,intensive cache writes can wear out the SSD quickly,which causes performance degradation and cost *** this article,we present the design and implementation of KDD, an efficient SSD-based caching system which Keeps Data and Deltas in *** write requests hit in the cache, KDD dispatches the data to the RAID storage without updating the parity blocks to mitigate the small write penalty, and compactly stores the compressed deltas in SSD to reduce the cache write traffic while guaranteeing reliability in case of disk *** addition,KDD organizes the metadata partition on SSD as a circular log to make the cache persistent with low *** evaluate the performance of KDD via both simulations and prototype *** results show that KDD effectively reduces the small write penalty while extending the lifetime of the SSD-based cache by up to 6.85 times.

关键词： solid-state drive (SSD) parity-based RAID small write problem write endurance

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Research progress in high-temperature thermo-mechanical behaviors for modelling Cr-coated cladding under loss-of-coolant accident condition

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Nuclear Engineering and design 2025年 439卷

作者： Yin, Chunyu Su, Guanghui Qian, Libo Xiong, Qingwen Liu, Yu Wu, Yingwei Du, Sijia Zhang, Jing Xiao, Zhong School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China National Key Laboratory of Nuclear Reactor Technology Nuclear Power Institute of China Chengdu610213 China

Chromium (Cr)-coated zirconium cladding has emerged as a leading candidate for accident tolerant fuel (ATF) cladding in near-term engineering applications. This cladding demonstrates enhanced resistance to high-temperature oxidation, superior mechanical properties at elevated temperatures, and a relatively high level of technological maturity. Its performance under loss-of-coolant accident (LOCA) conditions is critical to reactor safety, making it a key focus of the present study. The present work introduces an overview of research progress on high temperature thermo-mechanical behaviors for Cr-coated cladding and provides a set of fundamental safety analysis models tailored for LOCA scenarios. First, essential models for LOCA safety analysis of Cr-coated cladding are identified, including a high-temperature oxidation model (along with a Cr coating consumption model), a high-temperature creep model, a high-temperature burst model, and an embrittlement criterion. Second, based on the evaluation of experimental data from high-temperature oxidation studies, models for the growth of Cr2O3 layer and oxygen absorption are recommended to estimate the oxidation rate of Cr-coated cladding. Additionally, a model for Cr coating consumption is proposed. Subsequently, through a comprehensive review and reevaluation of high-temperature creep and burst data, corresponding models for Cr-coated cladding are developed respectively. Finally, embrittlement data for Cr-coated cladding are analyzed, and embrittlement criteria for both one-sided oxidation and two-sided oxidation conditions are proposed. © 2025

关键词： Thermooxidation

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Curvature-property coupling governed heat transfer deterioration in supercritical helically coiled tubes: Mechanistic insights and mitigation strategies via structural parametrization

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International Journal of Thermal sciences 2025年 215卷

作者： Chang, Fucheng Xin, Jiaxing Wu, Xiaoyi Li, Liwei Li, Huixiong Zhu, Yanlin National Key Lab of Aerospace Power System and Plasma Technology School of Mechanical Engineering Xi'an Jiaotong University Xi'an710049 China China Special Equipment Testing and Research Institute Beijing100029 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China Shanghai Nuclear Engineering Research & Design Institute Co. Ltd Shanghai200233 China

The unique thermo-hydrodynamic coupling phenomena in the helically coiled tube (HCT) handling supercritical fluids present both opportunities and challenges for next-generation compact heat exchangers. While the pronounced thermophysical property variations near pseudo-critical temperatures (Tpc) and curvature-induced secondary flows synergistically enhance heat transfer coefficient (HTC), their nonlinear coupling mechanisms may unexpectedly provoke severe heat transfer deterioration (HTD). Through systematic numerical investigations, this study reveals that circumferential wall temperature inhomogeneity (CWTI) exhibits an inverted N-shaped evolution, providing valuable insights for thermal homogenization design near Tpc. The secondary flow Reynolds number (Se), quantifying secondary flow intensity, shows a monotonic increase with decreasing coil diameter (Dc) or inner diameter (Di), reaching saturation in high-enthalpy regions. Notably, CWTI demonstrates non-monotonic behavior, achieving minimum values near Tpc before manifesting distinct rebound characteristics near Tpc conditions. Parametric analysis establishes that: (1) Elevating heat flux (q) increases Se, reducing Dc boosts it by 50.3 %, and decreasing Di raises it by 60.0 %. (2) HTD predominantly initiates at the outer wall under high-q conditions, with Dc reduction achieving HTD suppression and 26.9 % enhancement in the local HTC;(3) Reducing the Di results in a reduction of maximum CWTI by 22.5 %–28.6 %, suggesting that structural parametrization effectively mitigates wall temperature non-uniformity, thus suppressing the HTD. While centered on supercritical water, the dimensionless scaling relationships demonstrate extendibility to other media, with the curvature-property coupling mechanism both elucidating fundamental interactions and guiding robust heat exchanger design. © 2025 Elsevier Masson SAS

关键词： Electric heating

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Acoustic indeced vibration research of dryer in steam generator 26

Acoustic indeced vibration research of dryer in steam genera...

引用

26th International Congress on Sound and Vibration, ICSV 2019

作者： Xianhui, Ye Fengshou, Zhang Fengchun, Cai Wenzheng, Zhang Furui, Xiong Haiyang, Song Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9781999181000

The acoustic induced vibration of dryer (also called secondary separator) in steam generator in nuclear power plants is a concern in recent years. Periodic vibrations of long-term operation can lead to fatigue damage of structural components, posing a safety hazard. In this paper, the finite element analysis model of the dryer structure in steam generator of "Hualong-1" nuclear power plant was established, and the acoustic induced vibration characteristics of the structure were studied. Firstly, the acoustic excitation of the dryer structure was discussed, and the excitation inputs were obtained, including the maximum static pressure and the maximum pressure power spectrum density. Then the finite element model was established by ANSYS and the weak parts of the dryer structure were determined by the vibration characteristics combined with the acoustic excitation characteristics analysis. Finally, the structural strength and fatigue characteristics of the dryer structure under two different inputs of the acoustic load were investigated. The analysis of vibration characteristics shows that the main weak parts of the dryer structure are the vertical partition plate and the perforated plate. The static pressure analysis shows that the stress intensity of the two weak plates is less than the limit. In the study of pressure power spectral density, the maximum dynamic stress intensity and alternating stress of the vertical partition plate and the perforated plate are also less than the limit. The research results indicate that the acoustic induced vibration response of the dryer structure is within the acceptable range © Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019. All rights reserved.

关键词： Steam generators

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A Service-Environment-Oriented Shape Reconstruction Method of Vehicle-borne Active Phased Array Antenna

A Service-Environment-Oriented Shape Reconstruction Method o...

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2021 CIE International Conference on Radar, Radar 2021

作者： Xu, Pengying Xu, Xiaoxian Wang, Yan Teng, Yucheng Wang, Congsi Ge, Dongming Kang, Mingkui Yuan, Shuai Wang, Xuezi Xidian University Key Laboratory of Electronic Equipment Structure Design Ministry of Education Xi'an China School of Information and Control Engineering Xi'an University of Architecture and Technology Xi'an China Beijing Institute of Spacecraft System Engineering Beijing China No.771 Institute of China Aerospace Science and Technology Corporation Xi'an China China Electronics Technology Group Corporation No.38 Research Institute Hefei China

ISBN: (纸本)9781665498142

Modern electronic equipment has been moving towards large scale and increased complexity. Affected by such factors as complex working environments, the performance of a large number of structures in engineering is degraded or even destroyed. Therefore, structure shape estimation is of great significance. The complexity of the structure, however, makes it impossible for a single deformation evaluation algorithm to evaluate the structure comprehensively and accurately. In this paper, a modal-approximate curve (M-AC) method, using a small amount of strain data, is proposed for block shape estimation of structures. Three typical wind load experiments are carried out on the finite element model (FEM) of the vehicle-borne active phased array antenna, and the effectiveness of the algorithm is verified. Under the wind speed of 28 (m/s), the deformation of antenna front is 104.70 mm and the estimation accuracy of the M-AC method is 87.43%, which is 16.47% higher than that of the modal approach. The results indicate that the estimated displacement is consistent well with the simulation results of the finite element method. © 2021 IEEE.

关键词： active phased array antenna Fiber Bragg grating mode shapes sensor shape estimation

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Study on modal characteristics and vibration reduction of an aircraft rotor–stator brake-induced squeal system

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Acta Mechanica Sinica 2020年第6期36卷 1350-1359,I0004页

作者： Qiaozhi Yin Xiaohui Wei Hong Nie Jian Deng State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and AstronauticsNanjing210016China Nanjing Center for Multifunctional Lightweight Materials and Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

Based on the modal coupling theory,the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this *** the complex modal analysis and transient dynamic analysis methods are used to study the aircraft brake squeal performance and vibratory *** unstable vibration modes indicate that the out-of-plane vibration plays an important role and the feed-in energy is larger than the output energy in the brake rotor–stator module so that brake squeal takes *** the influences of the contact stiffness,friction damping and frictional coefficient on the brake squeal system are carried out,laying the foundation for the three proposed vibration suppression *** show that the coefficient negative-slope condition will intensify the ***,a linear relationship between the squeal factor and the frictional coefficient is obtained to provide a guidance to predict squeal stability under more *** reduction design shows that adding a damping layer to the brake mechanism and chamfering the edge of braking stators both can reduce brake squeal effectively,while slotting braking stators is invalid in aircraft braking system.

关键词： Aircraft rotor-stator bake-induced vibration Brake squeal-Vibration stability Modal coupling Vibration suppression

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Investigation of turbulent Prt model and the segmentation rule for LBE turbulent heat transfer 18

Investigation of turbulent Prt model and the segmentation ru...

引用

18th International Topical Meeting on Nuclear reactor Thermal Hydraulics, NURETH 2019

作者： Li, Peiying Yu, Hongxing Li, Meifu Du, Sijia Yan, Mingyu Liu, Yu Zhu, Dahuan Zhang, He Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

With liquid metal like lead-bismuth alloy(LBE) acting as a coolant for nuclear reactors, it is necessary to use a more accurate heat transfer relationship and a more reliable Prt model for the low Pr fluid. Because of the low Pr of liquid metal, the thermal conductivity is more dominant than the momentum transfer, which is quite different from ordinary fluids. In this case, the turbulent Prt can better reflect the heat transfer process. In this study, the Prt=A1+A2/Pr form is selected, and the corresponding coefficients are obtained by the renormalization group analysis method, then corrected by Pr. Furthermore, the applicable range and segmentation rule of the turbulent Prt model are discussed, and the obtained Prt segmentation theoretical model is written into CFD. The result shows that, compared with the previously unmodified model, the radial temperature distribution and Nusselt number (Nu) of the annular and bundle channel obtained by RANS method with the improved Prt model is in good agreement with experimental r esults, and the deviations are within 5%. It is proved that the turbulent Prt segmentation theoretical model proposed in this study is effective and can represent the heat transfer characteristics of liquid metal from the mechanism. © 2019 American Nuclear Society. All rights reserved.

关键词： Liquid metals

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