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A Coupled Thermomechanical Crack Propagation Behavior of Brittle Materials by Peridynamic Differential Operator

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 339-361页

作者： Tianyi Li Xin gu qing Zhang College of Architectural Engineering Jiangsu Open UniversityNanjing210036China Department of Engineering Mechanics Hohai UniversityNanjing211100China

This study proposes a comprehensive,coupled thermomechanical model that replaces local spatial derivatives in classical differential thermomechanical equations with nonlocal integral forms derived from the peridynamic differential operator(PDDO),eliminating the need for calibration *** model employs a multi-rate explicit time integration scheme to handle varying time scales in multi-physics *** simulations conducted on granite and ceramic materials,this model demonstrates its *** successfully simulates thermal damage behavior in granite arising from incompatible mineral expansion and accurately calculates thermal crack propagation in ceramic slabs during *** account for material heterogeneity,the model utilizes the Shuffle algorithm andWeibull distribution,yielding results that align with numerical simulations and experimental *** coupled thermomechanical model shows great promise for analyzing intricate thermomechanical phenomena in brittle materials.

关键词： Peridynamic differential operator thermomechanical coupling heterogeneity numerical simulation

TWO-DIMENSIONAL MODEL OF TRAFFIC FLOW CONTAINING ROAD SECTIONS

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Journal of Hydrodynamics 2004年第1期16卷 45-51页

作者： guguo-qing ZHANGWei QIANXin-jian ZHANGYong SchoolofInformationScienceandTechnology EastChinaNormalUniversityShanghai200062China InstituteofSystemsScience UniversityofShanghaiforScienceandTechnologyShanghai200093China

Both the cross and road section are basic components in traffic systems. Ageneral cellular automaton model of two-dimensional traffic flow containing road section wasestablished. The model was simulated with respect to various section lengths and the randomdistribution of section lengths. The effect of road sections on the performance of traffic flow wasdiscussed based on simulation results

关键词： traffic flow model cellular automaton traffic simulation

Hydrothermal Synthesis and Structure Analysis of Indium Vanadate (InVO_4)

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Chinese Journal of Structural Chemistry 2005年第11期24卷 1242-1248页

作者： HUANG qing-Ming YU jian-Chang Instrumentation Analysis and Research Center Fuzhou University Fuzhou Fujian 350002 China Material science and engineering department Fuzhou University Fuzhou Fujian 350002 China

In this article, hydrothermal process is applied to synthesize nanometer InVO4. Influences of different experimental conditions （including mixing ratio of raw materials, reaction temperature, reaction time and so on） upon the synthetic products＇ purity and crystallite size are discussed to determine the best synthetic condition. The structure of nanometer InVO4 is analyzed, which helps to further understand the structure characteristics of InVO4 synthesized by applying hydrothermal process and lays foundation for further research.

关键词： hydrothermal process InVO4 experimental conditions structure

Damping properties of fly ash/epoxy composites

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Journal of University of Science and Technology Beijing 2008年第4期15卷 509-513页

作者： jian gu Gaohui Wu Xiao Zhao School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

An inexpensive fly ash （FA）, which is from a waste product, was employed to prepare fly ash/epoxy composites. The purpose of this study is to characterize the contributions of matrix viscoelasticity, hollow structure characteristic （porosity）, and filler/matrix interface friction to the high vibration damping capacity of such composites. The damping properties of the composites were investigated in the temperature range of-40 to 150℃ and in the frequency range of 10 to 800 Hz by using a tension-compression mode. The results indicate that the peak value of damping loss factor （tan3） for the fly ash/epoxy composites can reach 0.70-0.90 in test specification, and the attenuation of damping loss factor is inconspicuous with increasing frequency. In addition, scanning electron microscope （SEM） was used to observe the morphology of the fly ash as well as its distribution in the matrix, which will help to analyze the effect of fly ash on the damping properties of the fly ash/epoxy composites.

关键词： composites epoxy fly ash damping property loss factor

The Origin of The Soft X-Ray Excess in the Seyfert 1.5 Galaxy ESO 362-G18

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Research in Astronomy and Astrophysics 2022年第3期22卷 10-32页

作者： Xiao-gu Zhong jian-Cheng Wang Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China

We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray *** Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in active galactic nuclei at *** use the simultaneous X-ray observation data of XMM-Newton and Nu STAR on2016 September 24 to perform spectral analysis in two ***,we analyze the time-average spectra by using Warm Corona and Relativistic Reflection ***,we also explore the Hybrid model,Double Reflection model and Double Warm Corona *** find that both the Warm Corona and Relativistic Reflection models can interpret the time-average spectra well but cannot be distinguished easily based on the time-averaged spectra fit ***,we add the rms and covariance spectra to perform the spectral analysis with time-average *** result shows that the warm corona could reproduce all of these spectra *** hot,optical thin corona and neutral distant reflection will increase their contribution with the temporal frequency,meaning that the corona responsible for X-ray continuum comes from the inner compact X-ray region and the neutral distant reflection is made of some moderate scale neutral clumps.

关键词： galaxies:active galaxies:individual(ESO 362-G18) galaxies:Seyfert

Adversarial data splitting for domain generalization

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Science China(Information Sciences) 2024年第5期67卷 28-42页

作者： Xiang gu jian SUN Zongben XU School of Mathematics and Statistics Xi'an Jiaotong University

Domain generalization aims to learn a model that is generalizable to an unseen target domain,which is a fundamental and challenging task in machine learning for out-of-distribution generalization. This paper proposes a novel domain generalization approach that enforces the learned model to be able to generalize well over the train/val subset splitting of the training dataset. This idea is modeled herein as an adversarial data splitting framework, formulated as a min-max optimization problem inspired by the metalearning approach. The min-max optimization problem is solved by iteratively splitting the training dataset into the training and val subsets to maximize the domain shift measured by the objective function and updating the model parameters to enable the model to generalize well from the training subset to the val subset by minimizing the objective function. This adversarial training approach does not assume the known domain labels of the training data; instead, it automatically investigates the “hard” splitting of the train/val subsets to learn the generalizable model. Extensive experimental results using three benchmark datasets demonstrate the superiority of this approach. In addition, we derive a generalization error bound for the theoretical understanding of our proposed approach.

关键词： domain generalization adversarial learning data splitting meta-learning out of distribution

Ready-to-implement low-carbon retrofit of coal-fired power plants in China:Optimal scenarios selection based on sludge and photovoltaic utilization

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Environmental Science and Ecotechnology 2022年第1期9卷 60-71页

作者： Yunchao Xia jian Deng Bo Hu qing Yang jianlan Li Hongqun gu guiping Zhou China-EU Institute for Clean and Renewable Energy Huazhong University of Science&TechnologyWuhan430074Hubei ProvinceChina State Key Laboratory of Coal Combustion Huazhong University of Science&TechnologyWuhan430074Hubei ProvinceChina State Grid Liaoning Electric Power Co. LtdShenyang110006Liaoning ProvinceChina School of Energy and Power Engineering Huazhong University of Science&TechnologyWuhan430074Hubei ProvinceChina

Currently the flexible demand for high proportion penetration of renewable energy depends on coal-fired units(CFUs),and the large-scale phase-out of CFUs in a short time is not realistic in *** to urban expansion,approximately 458 Chinese coal-fired power plants(CFPPs)are now located in *** by space,urban CFUs face difficulty in becoming equipped with carbon capture and storage *** presents a sizeable challenge for the low-carbon transition of urban CFPPs and carbon neutral ***,we present a ready-to-implement method to reduce the carbon emission of CFPPs in limited space:roof photovoltaic-assisted power generation combined with sludge cocombustion for coal-fired power generation systems(PVSCs).We also consider nonurban CFPPs with the method of roof photovoltaic-assisted power generation(PVs)*** on remaining life cycle analysis,we find that the PVSCs could save 28.47 Mt of coal,reduce CO_(2)emissions by 69.76 Mt,treat 125.70 Mt of sludge,and also generate 12.08 billion RMB worth of electricity revenue per *** addition,our scenario analysis shows that PVSCs are more profitable when choosing an urban CFU with a remaining life of more than 12 years and while the sludge treatment subsidy is set at 100 RMB t*** strict and lenient CFU decommissioning policies,CFUs with a remaining life of between 19 and 30 years and between 13 and 24 years should be selected for PVs,***,we conclude that PVSCs can not only generate economic benefits but also facilitate carbon reduction and solid waste treatment.

关键词： Roof photovoltaic Sludge co-combustion CFPPs Decarbonization Optimal emission target selection

An Image Fingerprint and Attention Mechanism Based Load Estimation Algorithm for Electric Power System

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 577-591页

作者： qing Zhu Linlin gu Huijie Lin Electricity Technology Branch Nari Technology Co.Ltd.Nanjing211106China NARI-TECH Nanjing Control Systems Co. Ltd.Nanjing211106China

With the rapid development of electric power systems,load estimation plays an important role in system operation and ***,load estimation techniques contain traditional,time series,regression analysis-based,and machine learning-based *** the machine learning-based method can lead to better performance,in this paper,a deep learning-based load estimation algorithm using image fingerprint and attention mechanism is ***,an image fingerprint construction is proposed for training *** the data preprocessing,the training data matrix is constructed by the cyclic shift and cubic spline ***,the linear mapping and the gray-color transformation method are proposed to form the color image ***,a convolutional neural network(CNN)combined with an attentionmechanism is proposed for training performance *** last,an experiment is carried out to evaluate the estimation *** with the support vector machine method,CNN method and long short-term memory method,the proposed algorithm has the best load estimation performance.

关键词： Load estimation deep learning attention mechanism image fingerprint construction

Cross-layer design of LT codes and LDPC codes for satellite multimedia broadcast/multicast services

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Chinese Journal of Aeronautics 2013年第5期26卷 1269-1275页

作者： Wang Zhenbang Wang Zhenyong gu Xuemai guo qing School of Electronics and Information Engineering Harbin Institute of Technology

According to large coverage of satellites, there are various channel states in a satellite broadcasting network. In order to introduce an efficient rateless transmission method to satellite multimedia broadcasting/multicast services with finite-length packets, a cross-layer packet transmission method is proposed with Luby transform （LT） codes for efficiency in the network layer and low density parity check （LDPC） codes for reliability in the physical layer jointly. The codewords generated from an LT encoder are divided into finite-length packets, which are encoded by an LDPC encoder subsequently. Based on noise and fading effects of satellite channels, the LT packets received from an LDPC decoder either have no error or are marked as erased, which can be mod- eled as a binary erasure channels （BECs）. By theoretical analysis on LT parameters and LDPC parameters, the relationships between LDPC code rates in the physical layer and LT codes word lengths in the network layer are investigated. With tradeoffs between the LT codes word lengths and the LDPC code rates, optimized cross-layer solutions are achieved with a binary search algorithm. Verified by simulations, the proposed solution for cross-layer parameters design can provide the best transmission mode according to satellite states, so as to improve throughput performance for satellite multimedia transmission.

关键词： Broadcast/multicast Cross-layer LDPC codes LT codes Satellite multimedia