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arXiv 2022年

作者： Li, Chengyuan Li, Meifu Qiu, Zhifang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China

Compared to knowledge-based diagnostic systems, data-based methods tend to perform better in terms of speed and accuracy in diagnosing reactor accidents, and have significant advantages in terms of scalability of models. With the increasing use of high-precision system analysis programs in nuclear engineering, the number of high-fidelity computational data for accident simulation is exploding. Therefore, an algorithm that can achieve both automatic extraction of low-dimensional features from the data and guarantee the validity of the features is needed to improve the performance and confidence of the accident diagnosis system. This study proposes an autoencoder-based autonomous learning framework, namely Padded Auto-Encoder (PAE), which is able to automatically encode accident monitoring data that has been noise-added and with partially missing data into low-dimensional feature vectors via a Vision Transformer-based encoder, and to decode the feature vectors into noise-free and complete reconstructed monitoring data. Thus, the encoder part of the framework is able to automatically infer valid representations from partially missing and noisy monitoring data that reflect the complete and noise-free original data, and the representation vectors can be used for downstream tasks for accident diagnosis or else. In this paper, LOCA of HPR1000 was used as the study object, and the PAE was trained by an unsupervised method using cases with different break locations and sizes as the dataset. The encoder part of the pre-trained PAE was subsequently used as the feature extractor for the monitoring data, and several basic statistical learning algorithms for predicting the break locations and sizes. The results of the study show that the pre-trained diagnostic model with two stages has a better performance in break location and size diagnostic capability with an improvement of 41.62% and 80.86% in the metrics respectively, compared to the diagnostic model with end-to-end model st

关键词： Extraction

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Imbibition Front and Phase Distribution in Shale Based on Lattice Boltzmann Method

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Computer Modeling in Engineering & sciences 2025年第2期142卷 2173-2190页

作者： Li Lu Yadong Huang Kuo Liu Xuhui Zhang Xiaobing Lu State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing100083China Center forDigital Technology Research Hubei Provincial Communications Planning and Design Institute CoLtd.Wuhan430051China Institute of Mechanics Chinese Academy of SciencesBeijing100190China College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China School of Engineering Science University of Chinese Academy of SciencesBeijing101408China

To study the development of imbibition such as the imbibition front and phase distribution in shale,the Lattice Boltzmann Method(LBM)is used to study the imbibition processes in the pore-throat network of *** dimensional analysis,four dimensionless parameters affecting the imbibition process were determined.A color gradient model of LBM was used in computation based on a real core pore size *** numerical results show that the four factors have great effects on *** impact of each factor is not *** imbibition process is the comprehensive effect of all *** imbibition front becomes more and more non-uniform with time in a heterogeneous pore-throat *** non-wetting phases(oil here)cannot be displaced *** displacement efficiency and velocity do not change monotonously with any *** development of the average imbibition length with time is not smooth and not linear in a heterogeneous pore-throat *** fitting relations between the four dimensionless parameters and the imbibition velocity and efficiency are obtained,respectively.

关键词： Imbibition LBM dimensional analysis shale

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Unified Inertia Modelling and Quantitative Comparative Analysis between Grid-Following and Grid-Forming Converters 10

Unified Inertia Modelling and Quantitative Comparative Analy...

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10th IEEE International Power Electronics and Motion Control Conference, IPEMC 2024 ECCE Asia

作者： Li, Xiaoyu Li, Zheyu Zhou, Shiying Ma, Jingran Zhu, Donghai Zou, Xudong Huazhong University of Science and Technology Power Electronics and Energy Management Key Laboratory Ministry of Education of China China Hubei Key Laboratory of Marine Electromagnetic Detection and Control China Wuhan Second Ship Design and Research Institute China

ISBN: (纸本)9798350351330

Grid-following (GFL) and grid-forming (GFM) converters with inertia control are essential ways to address the 'low-inertia' system problem. However, due to the different structures of the two converters, their inertia response performance is hard to evaluate. Several studies have attempted to compare them through simulation, but the absence of a unified and quantifiable inertia metric makes it difficult to get a fundamental comparison. To tackle this issue, the magnitude-phase motion equations for the two converters are derived in this paper, with the dynamic behaviors of multiple control loops considered. The structure of the swing equation is utilized to provide a unified description, and the extracted equivalent inertia is used to express their inertia characteristics quantitatively. Finally, the performance of the two converters is compared by simulation based on equivalent inertia. © 2024 IEEE.

关键词： Equations of motion

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Variable stiffness design optimization of fiber-reinforced composite laminates with regular and irregular holes considering fiber continuity for additive manufacturing

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Chinese Journal of Aeronautics 2025年第3期38卷 334-354页

作者： Yi LIU Zunyi DUAN Chunping ZHOU Yuan SI Chenxi GUAN Yi XIONG Bin XU Jun YAN Jihong ZHU School of Mechanics Civil Engineering&ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China Key Lab for Airborne Hi-performance Electro-magnetic Window RISACJinan 130012China School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen 518055China State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian 116024China State IJR Center of Aerospace Design and Additive Manufacturing MIIT Lab of Metal Additive Manufacturing and Innovative DesignNorthwestern Polytechnical UniversityXi’an 710072China

Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples cons

关键词： Variable stiffness composite laminates Discrete material interpolation scheme Normal distribution fiber optimization Discrete fiber continuous filtering strategy Additive manufacturing of composite laminates

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Extracting the effective mass of fewer layers 2D h-BN nanosheets using the Fowler-Nordheim tunneling model

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红外与毫米波学报 2024年第6期43卷 744-748页

作者： QIN Jia-Yi LUO Man CHENG Tian-Tian MENG Yu-Xin ZU Yuan-Ze WANG Xin YU Chen-Hui Jiangsu Key Laboratory of ASIC Design School of Information Science and TechnologyNantong UniversityNantong 226019China State Key Laboratory of Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

Hexagonal boron nitride(h-BN)is found to have widespread application,owing to its outstanding properties,including gate dielectrics,passivation layers,and tunneling *** current studies on the funda⁃mental physical properties of these ultrathin h-BN films and the electron tunneling effect among them are inade⁃*** this work,the effective mass in h-BN was successfully determined through a combined approach of ex⁃perimental and theoretical research methods by fitting the current-voltage curves of metal/insulator/metal struc⁃*** was observed that within a range of 4-22 layers,the effective mass of h-BN exhibits a monotonic de⁃crease with an increase in the number of *** physical parameters of the Fowler-Nordheim tunneling model in the context of electron tunneling in h-BN are precisely ascertained by utilizing the extracted effective ***⁃ditionally,the impact of fixed charges at the metal/h-BN interface and various metal electrode types on FowlerNordheim tunneling within this structure is investigated utilizing this physical parameter in Sentaurus TCAD soft⁃*** work is informative and instructive in promoting applications in the fields of h-BN related infrared physics and technology.

关键词： h-BN 2D layered material Fowler-Nordheim tunneling gate dielectrics TCAD simulation

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Enhanced Isolation Between Two Closely Spaced Vivaldi Antennas Using a Rasorber Wall

Enhanced Isolation Between Two Closely Spaced Vivaldi Antenn...

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IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP)

作者： Xianliang Zeng Xujing Huang Weijun Wu Li Tao Shuang Li China Ship Development and Design Center Science and Technology on Electromagnetic Compatibility Laboratory

ISBN: (数字)9798350351019

ISBN: (纸本)9798350351026

An effective method for enhancing the isolation between two Vivaldi antennas using a metamaterial wall with rasorber is proposed in this work. The mutual coupling is reduced by adding the rasorber wall, which can absorb the electromagnetic (EM) interference energy from the transmitting antenna to the receiving antenna. The designed rasorber wall is constructed by two kinds of frequency selective surface (FSS) and foam substrate. Due the good absorption of the rasorber structure, the isolation between antennas has enhanced by more than 15 dB on average at X band.

关键词： Mutual coupling Simulation Vivaldi antennas Transmitting antennas Receiving antennas Interference Metamaterials Electromagnetics Substrates Gain

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Effect of dimensionless heat input during laser solid forming of high-strength steel

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Journal of Materials science & technology 2022年第4期99卷 127-137页

作者： Chunping Huang Renyu Liang Fenggang Liu Haiou Yang Xin Lin National Defense Key Discipline Laboratory of Light Alloy Processing Science and Technology Nanchang Hangkong UniversityNanchang 330063China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

Laser solid forming(LSF)technology can be used to rapidly manufacture and repair high-strength steel parts with superior performance,but the value of the heat input during operation is difficult to quantify,which has a substantial impact on the microstructure and mechanical properties of the parts.A promising method to improve the forming efficiency and quality of LSFed parts is to accurately control the heat input and explore its relationship with the microstructure and mechanical *** remove the interference of other variables from the experiment,the dimensionless heat input Q;^(∗)was *** Q^(∗)values were designed in advance to calculate the experimental parameters used to perform the LSF *** microstructure was observed at different regions of the sample,and its mechanical properties were *** the results,the following conclusions were *** Q;^(∗)value was directly related to the cooling rate and heat accumulation in the top structure,leading to the formation of different microstructures;it also modified the original structure at the bottom,affecting the subsequent thermal cycle and indirectly changing the tempered martensite *** heat input also affected the mechanical properties of the *** hardness of the stable zone decreased with increasing Q;^(∗)value,and the lowest value was 190 ***,the tensile strength and yield strength of the LSFed samples decreased considerably with increasing Q;^(∗)value,and the lowest values were 735 and 604 MPa,*** the elongation and reduction in the area increased after a slight *** Q;^(∗)value had a significant effect on heat *** Q;^(∗)=2.9,the increase in tensile strength and yield strength after heat treatment was the largest(29%and 44%,respectively).

关键词： Dimensionless heat input Laser solid forming High-strength steel Microstructure Mechanical property

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Effect of the atomic orbital on the retrieval of the ionization time on the basis of a phase-of-phase attoclock: F− ions as an example

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Physical Review A 2024年第1期110卷 013113-013113页

作者： Jian-Hong Chen Haiyuan Yu Hongchuan Du School of Electronic Engineering School of Nuclear Science and Technology Key Laboratory of Special Function Materials and Structure Design Ministry of Education

Recently, the phase-of-phase (POP) attoclock scheme [reported in Nature Photon. 15, 765 (2021)] has been used to investigate the tunneling dynamics of krypton atoms, encompassing the electron sub-barrier phase and amplitude. However, the impact of initial atomic orbitals on the POP attoclock spectroscopy remains largely unexplored. Here, we scrutinize the influence of initial atomic orbitals on the contrast and phase spectra of POP attoclock using F− ions as a specific example. It is found that the initial atomic orbital significantly impacts the contrast spectrum of the POP attoclock and the detachment time of low-energy electrons retrieved by the POP attoclock via the preexponential factor. Particularly for orbitals p+ and p−, the difference of retrieved detachment time can exceed 300 attoseconds at some emission angles. But for high-energy electrons, the detachment time is almost independent of the initial atomic orbital and can be accurately retrieved by the POP attoclock. This work underscores the profound influence of initial atomic orbitals on the measurement accuracy of the POP attoclock, and holds great significance for advancing POP attoclock spectroscopy.

关键词： Single- and few-photon ionization & excitation Strong electromagnetic field effects Ultrafast phenomena

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Nitrate-responsive OsMADS27 promotes salt tolerance in rice

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Plant Communications 2023年第2期4卷 136-150页

作者： Alamin Alfatih Jing Zhang Ying Song Sami Ullah Jan Zi-Sheng Zhang Jin-Qiu Xia Zheng-Yi Zhang Tahmina Nazish Jie Wu Ping-Xia Zhao Cheng-Bin Xiang Division of Life Sciences and Medicine Division of Molecular&Cell BiophysicsHefei National Science Center for Physical Sciences at the MicroscaleMOE Key Laboratory for Membraneless Organelles and Cellular DynamicsUniversity of Science and Technology of ChinaThe Innovation Academy of Seed DesignChinese Academy of SciencesHefeiAnhui Province 230027China

Salt stress is a major constraint on plant growth and ***(N)fertilizers are known to alleviate salt ***,the underlying molecular mechanisms remain ***,we show that nitratedependent salt tolerance is mediated by OsMADS27 in *** expression of OsMADS27 is specifically induced by *** salt-inducible expression of OsMADS27 is also nitrate ***27 knockout mutants are more sensitive to salt stress than the wild type,whereas OsMADS27 overexpression lines are more *** analyses revealed that OsMADS27 upregulates the expression of a number of known stress-responsive genes as well as those involved in ion homeostasis and *** demonstrate that OsMADS27 directly binds to the promoters of OsHKT1.1 and OsSPL7 to regulate their ***,OsMADS27-mediated salt tolerance is nitrate dependent and positively correlated with nitrate *** results reveal the role of nitrate-responsive OsMADS27 and its downstream target genes in salt tolerance,providing a molecular mechanism for the enhancement of salt tolerance by nitrogen fertilizers in ***27 overexpression increased grain yield under salt stress in the presence of sufficient nitrate,suggestingthatOsMADS27 is a promising candidate for the improvementof salt tolerance inrice.

关键词： OsMADS27 nitrate-dependent salt tolerance salt stress grain yield

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Experimental Study on Turbulent Characteristics of Dispersed Bubbly Flow in a Narrow Rectangular Channel by Two-Phase Piv

SSRN

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SSRN 2023年

作者： Chen, Wuguang Huang, Guangyuan Hu, Yuanbiao Junlian, Yin Wang, Dezhong Li, Songwei Yang, Fan School of Nuclear Science and Engineering Shanghai Jiaotong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

Narrow rectangular channels are widely used in high heat flux applications, due to the high heat transfer efficiency and compact structure. However, a rare understanding was known about the two-phase turbulent characteristics. In this study, an experimental investigation of bubble and turbulent characteristics of dispersed bubbly flow in the narrow rectangular channel was carried out by using the high-speed camera and two-phase particle image velocimetry. The bubble size effect was studied independently using the continuous spectrum bubble generator. According to the results, the bubble size distribution conforms to a Weibull distribution, and the wall-peak void fraction distributions were found. Both turbulent enhancement and suppression were observed in current conditions. Large bubbles enhance turbulence intensity, while small bubbles suppress it. The eddy viscosity ratio [[EQUATION]] characterizes the modification of turbulence intensity by bubbles, with a critical value of [[EQUATION]]. © 2023, The Authors. All rights reserved.

关键词： High speed cameras

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