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China Ocean engineering 2024年第3期38卷 394-407页

作者： HU Ze-bo LIU Zhen LI Peng GUO Hai-yan REN Xiao-hui HOU Hao HAO Lian-hong college of Civil engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of Marine Civil engineering Materials and Structures Qingdao 266590China college of engineering Ocean University of ChinaQingdao 266100China

In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined flume.The experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the risers.Three rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged downstream.The experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity increases.For the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced velocity.For the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’region.When the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.

关键词： marine riser vortex-induced vibration tandem arrangement roughness interference effect

Effects of longitudinal magnetic field on primary dendrite spacing and segregation of directionally solidified single crystal superalloy

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Progress in Natural Science:Materials International 2024年第1期34卷 26-36页

作者： Congjiang Zhang Yilin Zhou Chen Shen Weili Ren Xiaotan Yuan Biao Ding Haibiao Lu Zuosheng Lei Yunbo Zhong Ang Zhang State Key Laboratory of Advanced Special Steel College of Materials Science and Engineering Shanghai University National engineering Research Center for Magnesium Alloys Natural Key Laboratory of Advanced Casting Technologies College of Materials Science and EngineeringChongqing University

The primary dendrite spacing(PDS) and segregation of directionally solidified single crystal(SC) superalloy under the longitudinal magnetic field(LMF) were investigated based on the analysis of the whole cross-sectional microstructure at different solidification distances. The results show that the PDS under the LMF remains basically unchanged at different solidification distances, and it is greater than that under no LMF. With the increase of magnetic field intensity, the PDS increases and the macrosegregation decreases. The increasing PDS and reducing segregation under the LMF can be attributed to the increase of solute boundary layer, which expands the non-equilibrium freezing temperature range and brings the effective partition coefficient closer to 1. The increase of the solute enrichment layer thickness could be caused by the downward secondary circulation generated by the thermoelectric magnetic convection(TEMC) near the interface, which drives the migration of solutes towards the interdendritic region. This work not only clarifies the mechanism of LMF controlling PDS and reducing segregation by TEMC, but also provides theoretical guidance for producing high-quality SC superalloys using magnetic fields.

关键词： Primary dendrite spacing Segregation Single crystal superalloy Directional solidification Magnetic field Thermoelectric magnetic convection

An improved algorithm based on equivalent sound velocity profile method at large incident angle

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Acta Oceanologica Sinica 2024年第2期43卷 161-167页

作者： Qianqian Li Qian Tong Fanlin Yang Qi Li Zhihao Juan Yu Luo college of Geodesy and Geomatics Shandong University of Science and TechnologyQingdao 266590China college of Underwater Acoustic engineering Harbin Engineering UniversityHarbin 150001China

With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing method.The classical equivalent sound speed profile(ESSP)method replaces the measured sound velocity profile(SVP)with a simple constant gradient SVP,reducing the computational workload of beam positioning.However,in deep-sea environment,the depth measurement error of this method rapidly increases from the central beam to the edge beam.By analyzing the positioning error of the ESSP method at edge beam,it is discovered that the positioning error increases monotonically with the incident angle,and the relationship between them could be expressed by polynomial function.Therefore,an error correction algorithm based on polynomial fitting is obtained.The simulation experiment conducted on an inclined seafloor shows that the proposed algorithm exhibits comparable efficiency to the original ESSP method,while significantly improving bathymetry accuracy by nearly eight times in the edge beam.

关键词： equivalent sound speed profile ray tracing method large incident angle edge beam deep sea error correction multibeam echo-sounder system

MOF-derived porous graphitic carbon with optimized plateau capacity and rate capability for high performance lithium-ion capacitors

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 395-404页

作者： Ge Chu Chaohui Wang Zhewei Yang Lin Qin Xin Fan college of Materials Science&engineering Guilin University of TechnologyGuilin 541004China Institute of Energy Innovation College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China

The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl solu-tion.The as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion storage.Additionally,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).

关键词： metal-organic framework porous graphitic carbon optimized plateau capacity kinetic analysis lithium-ion capacitor

Separation identification of a neural fuzzy Wiener–Hammerstein system using hybrid signals

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Frontiers of Information Technology & Electronic engineering 2024年第6期25卷 856-868页

作者： Feng LI Hao YANG Qingfeng CAO college of Electrical and Information engineering Jiangsu University of TechnologyChangzhou 213001China college of Electrical Energy and Power EngineeringYangzhou UniversityYangzhou 225127China

A novel separation identification strategy for the neural fuzzy Wiener–Hammerstein system using hybrid signals is developed in this study.The Wiener–Hammerstein system is described by a model consisting of two linear dynamic elements with a nonlinear static element in between.The static nonlinear element is modeled by a neural fuzzy network(NFN)and the two linear dynamic elements are modeled by an autoregressive exogenous(ARX)model and an autoregressive(AR)model,separately.When the system input is Gaussian signals,the correlation technique is used to decouple the identification of the two linear dynamic elements from the nonlinear element.First,based on the input and output of Gaussian signals,the correlation analysis technique is used to identify the input linear element and output linear element,which addresses the problem that the intermediate variable information cannot be measured in the identified Wiener–Hammerstein system.Then,a zero-pole match method is adopted to separate the parameters of the two linear elements.Furthermore,the recursive least-squares technique is used to identify the nonlinear element based on the input and output of random signals,which avoids the impact of output noise.The feasibility of the presented identification technique is demonstrated by an illustrative simulation example and a practical nonlinear process.Simulation results show that the proposed strategy can obtain higher identification precision than existing identification algorithms.

关键词： Wiener-Hammerstein system Neural fuzzy network Correlation analysis technique Hybrid signals Separation identification

Blind Signal Reception in Downlink Generalized Spatial Modulation Multiuser MIMO System Based on Minimum Output Energy

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Chinese Journal of Electronics 2024年第2期33卷 504-515页

作者： Wei-Chiang WU college of Mechanical and Electrical engineering Sanming University

This paper considers downlink multiuser multiple-input-multiple-output system with parallel spatial modulation scheme, in which base station transmitter antennas are separated into K groups corresponding to K user terminals. Generalized spatial modulation is employed, in which a subset(more than single antenna) of transmit antenna array are activated and the activating pattern corresponds to specific spatial symbol. Different from existing precoding-based algorithms, we develop a two-stage detection scheme at each user terminal: In the pre-processing stage, a minimax algorithm is proposed to identify the indices of active antennas, where the key idea is that the minimum output energy of the detector is maximized; A constrained minimum output energy algorithm is proposed in the post-processing stage to mitigate multiuser interference and extract temporal symbols. Compared with existing precoding-based algorithms, the complexity is significantly reduced. Moreover, the proposed algorithm is semi-blind,in which only a small subset of channel state information is required to identify active antennas as well as eliminate multiuser interference. Simulation results demonstrate that the proposed algorithm is near-far resistant and the spectral efficiency is extensively increased compared to the conventional spatial modulation scheme.

关键词： Generalized spatial modulation Multiuser multiple-input-multiple-output Multiuser interference Minimum output energy Minimax

Tunable hexagonal boron nitride topological optical delay line in the visible region

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Chinese Optics Letters 2024年第5期22卷 124-130页

作者：费宏明武敏林瀚杨毅彪肖连团 college of Physics Taiyuan University of TechnologyTaiyuan 030024China college of Information engineering Shanxi Vocational University of Engineering Science and TechnologyJinzhong 030619China college of Science RMIT UniversityMelbourneVictoria 3000Australia college of Electronic Information and Optical engineering Taiyuan University of TechnologyTaiyuan 030024China

Tunability,ultracompact design,high group index,low loss,and broad bandwidth are desired properties for integrated optical delay lines(ODLs).However,those properties are challenging to achieve simultaneously in the visible region.This paper proposes a tunable hexagonal boron nitride topological optical delay line(ODL)in the visible region based on valley photonic crystals.The topological edge state from the beard-type boundary allows the achievement of an ultralow group velocity close to zero,which results in a large group index of 629 at 645 nm.Moreover,we demonstrate tuning of the slow-light wavelength and optical delay times with electrically tunable liquid crystals by applying external voltage.The device has an ultracompact size of 5μm×2.7μm with an optical delay distance of 25a(a is the lattice constant)and a delay time of 12 ps.Our design can provide a new possibility for designing ODLs working in the visible region for optical communication and quantum computing systems.

关键词： valley photonic crystal topological edge states optical delay lines

Adaptive Observer-Based Finite-Time Fault Tolerant Control for Non-Strict Feedback Systems

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Journal of Systems Science & Complexity 2024年第4期37卷 1526-1544页

作者： SHENG Ning LIU Yang CHI Ronghu AI Zidong college of Automation and Electronic engineering Qingdao University of Science and Technology

This paper considers the adaptive finite-time control and observer design method for a class of non-strict feedback systems with unmeasurable states, unknown nonlinear dynamics and actuator faults. In this paper, an observer is proposed to estimate the unmeasurable states in finite-time based on adaptive technique and neural networks, while the actuator faults are not included. Command filter is used to solve the computational explosion and singularity problems caused by the traditional backstepping and non-strict feedback structure, respectively. Since the fault efficiency indicators in real systems are not available, two-layer neural networks are adopted, where the first network is to estimate the unknown nonlinearities of systems and the second one is to estimate fault efficiency indicators and unknown nonlinear terms. The proposed scheme guarantees that states are bounded through stability theorem. Finally, two experiments including a numerical example and a spring-mass-damper system are given to verify the effectiveness of the proposed method.

关键词： Command filter fault tolerant control finite-time control non-strict systems two-layer neural networks

Operational requirements analysis method based on question answering of WEKG

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Journal of Systems engineering and Electronics 2024年第2期35卷 386-395页

作者： ZHANG Zhiwei DOU Yajie XU Xiangqian MA Yufeng JIANG Jiang TAN Yuejin college of Systems engineering National University of Defense TechnologyChangsha 410073China

The weapon and equipment operational requirement analysis(WEORA) is a necessary condition to win a future war,among which the acquisition of knowledge about weapons and equipment is a great challenge. The main challenge is that the existing weapons and equipment data fails to carry out structured knowledge representation, and knowledge navigation based on natural language cannot efficiently support the WEORA. To solve above problem, this research proposes a method based on question answering(QA) of weapons and equipment knowledge graph(WEKG) to construct and navigate the knowledge related to weapons and equipment in the WEORA. This method firstly constructs the WEKG, and builds a neutral network-based QA system over the WEKG by means of semantic parsing for knowledge navigation. Finally, the method is evaluated and a chatbot on the QA system is developed for the WEORA. Our proposed method has good performance in the accuracy and efficiency of searching target knowledge, and can well assist the WEORA.

关键词： operational requirement analysis weapons and equipment knowledge graph(WEKG) question answering(QA) neutral network

Data-driven Surrogate-assisted Method for High-dimensional Multi-area Combined Economic/Emission Dispatch

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 52-64页

作者： Chenhao Lin Huijun Liang Aokang Pang Jianwei Zhong Yongchao Yang the college of Intelligent Systems Science and engineering Hubei Minzu UniversityEnshiChina

Multi-area combined economic/emission dispatch(MACEED)problems are generally studied using analytical functions.However,as the scale of power systems increases,ex isting solutions become time-consuming and may not meet oper ational constraints.To overcome excessive computational ex pense in high-dimensional MACEED problems,a novel data-driven surrogate-assisted method is proposed.First,a cosine-similarity-based deep belief network combined with a back-propagation(DBN+BP)neural network is utilized to replace cost and emission functions.Second,transfer learning is applied with a pretraining and fine-tuning method to improve DBN+BP regression surrogate models,thus realizing fast con struction of surrogate models between different regional power systems.Third,a multi-objective antlion optimizer with a novel general single-dimension retention bi-objective optimization poli cy is proposed to execute MACEED optimization to obtain scheduling decisions.The proposed method not only ensures the convergence,uniformity,and extensibility of the Pareto front,but also greatly reduces the computational time.Finally,a 4-ar ea 40-unit test system with different constraints is employed to demonstrate the effectiveness of the proposed method.

关键词： Multi-area combined economic/emission dispatch high-dimensional power system deep belief network data driven transfer learning