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Anisotropic Rock Poroelasticity Evolution in Ultra-low Permeability Sandstones under Pore Pressure,Confining Pressure,and Temperature:Experiments with Biot's Coefficient

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Acta Geologica Sinica(English Edition) 2021年第3期95卷 937-945页

作者： du Shuheng State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

This study aimed to show anisotropic poroelasticity evolution in ultra-low permeability reservoirs under pore pressure,confining pressure,and *** groups of experiments examining Biot's coefficient under different conditions were carried *** showed that Biot's coefficient decreased with increased pore pressure,and the variation trend is linear,but the decreasing rate is variable between ***'s coefficient increased with increased confining pressure;the variation trend is linear,but the increasing rate varies by material as ***,Biot's coefficient remains stable with increased ***,clay mineral content,particle arrangement,and pore arrangement showed impacts on Biot's *** strong hydrophilic clay minerals,expansion in water could result in a strong surface adsorption reaction,which could result in an increased fluid bulk modulus and higher Biot's *** skeleton minerals with strong lipophilicity,such as quartz and feldspar,increased oil saturation will also result in an adsorption reaction,leading to increased fluid bulk modulus and a higher Biot's *** study's conclusions provide evidence of poroelasticity evolution of ultra-low permeability and help the enhancing oil recovery(EOR)process.

关键词： Biot's coefficient ultra-low permeability pore pressure confining pressure temperature

An Alternative Way of Utilizing Fixed Point Theory

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Chinese Annals of Mathematics,Series B 2020年第6期41卷 861-872页

作者： Dapeng du Department of Mathematics and Statistics Northeast Normal UniversityChangchun 130024China

The author proposes an alternative way of using fixed point theory to get the existence for semilinear *** an example,a nonlocal ordinary differential equation is *** idea is to solve homogeneous equations in the *** feature of this method is that it does not need the equation to have special structures,for instance,variational structures,maximum principle,*** speaking,the existence comes from good properties of the suitably linearized *** idea may have wider application.

关键词： Existence Semi-linear equations Fixed point theory Homogeneous linearization

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广域确定性网络传输技术综述

软件学报 2025年第1期36卷 371-398页

作者：李彤徐都玲吴波郭雄文蒋岱均罗成卢卫杜小勇数据工程与知识工程教育部重点实验室(中国人民大学) 中国人民大学信息学院腾讯科技有限公司

广域网作为连接新业务、新基础设施和各类新型应用的纽带,已成为21世纪最重要的基础设施之一.近年来,数据量爆炸性增长,伴随着基于广域网的大模型、数字经济、元宇宙和全息社会等新型应用形态的持续涌现,以及东数西算、算力网络和数据... 详细信息

广域网作为连接新业务、新基础设施和各类新型应用的纽带,已成为21世纪最重要的基础设施之一.近年来,数据量爆炸性增长,伴随着基于广域网的大模型、数字经济、元宇宙和全息社会等新型应用形态的持续涌现,以及东数西算、算力网络和数据场等新型业务架构的出现,业务对广域网的数据传输服务质量提出了越来越高的要求.以时延为例,广域网不仅需要提供及时的服务,还需要提供准时的服务,即时延成为必须满足的确定性指标.因此,广域确定性网络作为广域网的新范式应运而生.系统地综述确定性网络的内涵,回顾传统确定性网络相关技术发展脉络,介绍广域确定性网络的新应用,探讨广域网确定性网络传输具有的新特征以及面临的新挑战,并提出广域确定性网络的新目标.基于上述新应用、新特征、新挑战和新目标,详细总结当前广域确定性网络领域的主要研究进展,并给出未来研究的方向.期望能为广域确定性网络领域的研究提供参考和帮助.

关键词：广域网确定性网络数据传输改良式革命式

A Practical Regular LDPC Coded Scheme for Physical-Layer Information Security

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China Communications 2024年第5期21卷 190-201页

作者： du Junyi CETC Key Laboratory of Avionic Information System Southwest China Institute of Electronic TechnologyChengdu 610036China

In this paper,we aim to design a practical low complexity low-density parity-check(LDPC)coded scheme to build a secure open channel and protect information from *** this end,we first propose a punctured LDPC coded scheme,where the information bits in a codeword are punctured and only the parity check bits are transmitted to the *** further propose a notion of check node type distribution and derive multi-edge type extrinsic information transfer functions to estimate the security performance,instead of the well-known weak metric bit error *** optimize the check node type distribution in terms of the signal-to-noise ratio(SNR)gap and modify the progressive edge growth algorithm to design finite-length *** results show that our proposed scheme can achieve a lower computational complexity and a smaller security gap,compared to the existing scrambling and puncturing schemes.

关键词： extrinsic information transfer function physical layer scheme secure open channel security gap

Modeling of Fatigue Crack Growth Closure Considering the Integrative Effect of Cyclic Stress Ratio,Specimen Thickness and Poisson's Ratio

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 816-825页

作者： LIU Jiantao du Pingan LIU Xiaobao du Qiang College of Mechanical and Electronic Engineering University of Electronic Science and Technology of China Chengdu 611731 China

Key components of large structures in aeronautics industry are required to be made light and have long enough fatigue *** is of vital importance to estimate the fatigue life of these structures *** the FCG process is affected by various factors,no universal model exists due to the complexity of the *** of the existing models are obtained by fitting the experimental data and could hardly describe the integrative effect of most existing factors *** order to account for the integrative effect of specimen parameters,material property and loading conditions on FCG process,a new model named integrative influence factor model（IIF） is proposed based on the plasticity-induced crack closure *** to the predictions of crack opening ratio（γ） and effective stress intensity factor range ratio（U） with different material under various loading conditions,predictions of γ and U by the IIF model are completely identical to the theoretical results from the plane stress state to the plane strain state when Poisson＇s ratio equals 1/*** Poisson＇s ratio equals 0.3,predictions of γ and U by the IIF model are larger than the predictions by the existing model,and more close to the theoretical *** addition,it describes the influence of R ratios on γ and U effectively in the whole region from-1.0 to ***,several sets of test data of FCG rates in 5 kinds of aluminum alloys with various specimen thicknesses under different loading conditions are used to validate the IIF model,most of the test data are situated on the predicted curves or between the two curves that represent the specimen with different thicknesses under the same stress *** of the test data slightly departure from the predictions by the IIF model due to the surface roughness and errors in ***,based on the analysis of the physical rule of crack opening ratios,a relative thickness of specimen is defined to describe the influence of mate

关键词： fatigue crack growth crack opening stress cyclic stress ratio constraint factor Poisson's ratio stress intensity factor

Voter model on adaptive networks

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Chinese Physics B 2022年第5期31卷 780-790页

作者： Jinming du Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationShenyang 110819China Institute of Industrial and Systems Engineering College of Information Science and EngineeringNortheastern UniversityShenyang 110819China Liaoning Engineering Laboratory of Operations Analytics and Optimization for Smart Industry Northeastern UniversityShenyang 110819China

Voter model is an important basic model in statistical *** recent years,it has been more and more used to describe the process of opinion formation in *** real complex systems,the interactive network of individuals is dynamically adjusted,and the evolving network topology and individual behaviors affect each ***,we propose a linking dynamics to describe the coevolution of network topology and individual behaviors in this paper,and study the voter model on the adaptive *** theoretically analyze the properties of the voter model,including consensus probability and *** evolution of opinions on dynamic networks is further analyzed from the perspective of evolutionary ***,a case study of real data is shown to verify the effectiveness of the theory.

关键词： statistical physics opinion dynamics evolutionary game theory complex systems

A heuristic cabin-type component alignment method based on multi-source data fusion

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Chinese Journal of Aeronautics 2020年第8期33卷 2242-2256页

作者： Hao YU Fuzhou du School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China

In cabin-type component alignment, digital measurement technology is usually adopted to provide guidance for assembly. Depending on the system of measurement, the alignment process can be divided into measurement-assisted assembly(MAA) and force-driven assembly. In MAA,relative pose between components is directly measured to guide assembly, while in force-driven assembly, only contact state can be recognized according to measured six-dimensional force and torque(6 D F/T) and the process is completed based on preset assembly strategy. Aiming to improve the efficiency of force-driven cabin-type component alignment, this paper proposed a heuristic alignment method based on multi-source data fusion. In this method, measured 6 D F/T, pose data and geometric information of components are fused to calculate the relative pose between components and guide the movement of pose adjustment platform. Among these data types, pose data and measured 6 D F/T are combined as data set. To collect the data sets needed for data fusion, dynamic gravity compensation method and hybrid motion control method are designed. Then the relative pose calculation method is elaborated, which transforms collected data sets into discrete geometric elements and calculates the relative poses based on the geometric information of ***, experiments are conducted in simulation environment and the results show that the proposed alignment method is feasible and effective.

关键词： Alignment strategy Force-driven assembly Heuristic alignment method Multi-source data fusion Relative pose calculation

Transformer and GAN-Based Super-Resolution Reconstruction Network for Medical Images

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Tsinghua Science and Technology 2024年第1期29卷 197-206页

作者： Weizhi du Shihao Tian Arts&Sciences College Washington University in St.LouisSt.LouisMO 63130USA Department of Electric and Computing Engineering Cornell UniversityIthacaNY 14850USA

Super-resolution reconstruction in medical imaging has become more demanding due to the necessity of obtaining high-quality images with minimal radiation dose,such as in low-field magnetic resonance imaging(MRI).However,image super-resolution reconstruction remains a difficult task because of the complexity and high textual requirements for diagnosis *** this paper,we offer a deep learning based strategy for reconstructing medical images from low resolutions utilizing Transformer and generative adversarial networks(T-GANs).The integrated system can extract more precise texture information and focus more on important locations through global image matching after successfully inserting Transformer into the generative adversarial network for picture ***,we weighted the combination of content loss,adversarial loss,and adversarial feature loss as the final multi-task loss function during the training of our proposed model *** comparison to established measures like peak signal-to-noise ratio(PSNR)and structural similarity index measure(SSIM),our suggested T-GAN achieves optimal performance and recovers more texture features in super-resolution reconstruction of MRI scanned images of the knees and belly.

关键词： super-resolution image reconstruction Transformer generative adversarial network(GAN)

How will our knowledge of short gamma-ray bursts affect the distance measurement of binary neutron stars?

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Science China(Physics,Mechanics & Astronomy) 2022年第1期65卷 103-118页

作者： Minghui du Lixin Xu Institute of Theoretical Physics School of PhysicsDalian University of TechnologyDalian 116024China

Gravitational waves from binary neutron stars associated with short gamma-ray bursts have drawn considerable attention due to their prospect in *** such events,the sky locations of sources can be pinpointed with techniques such as identifying the host ***,the cosmological applications of these events still suffer from the problem of degeneracy between luminosity distance and inclination *** address this issue,a technique was proposed in previous study,i.e.,using the collimation property of short gamma-ray *** on the observations,we assume that the cosine of inclination follows a Gaussian distribution,which may act as a prior in the Bayes analysis to break the *** paper investigates the effects of different Gaussian priors and detector configurations on distance measurement and cosmological *** first derive a simplified Fisher information matrix for demonstration,and then conduct quantitative analyses via *** varying the number of third-generation detectors and the scale of prior,we generate four catalogs of 1000 *** is shown that,in the same detecting period,a network of detectors can recognize more and farther events than a single ***,adopting tighter prior and employing multiple detectors both decrease the error of luminosity *** considered is the performance of a widely adopted formula in the error budget,which turns out to be a conservative choice in each *** for cosmological applications,for theΛCDM model,500,200,600,and 300 events are required for the four configurations to achieve 1%H;*** all 1000 events in each catalog,H;and?;can be constrained to(0.66%,0.37%,0.76%,0.49%),and(0.010,0.006,0.013,0.010),*** results of the Gaussian process also show that the gravitational wave standard siren can serve as a probe of cosmology at high redshifts.

关键词： gravitational wave binary neutron star short gamma-ray burst cosmology