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A novel box-counting method for quantitative fractal analysis of threedimensional pore characteristics in sandstone

International Journal of Mining Science and Technology 2024年第4期34卷 479-489页

作者： Huiqing liu Heping xie Fei Wu Cunbao li Renbo Gao State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China School of Resources and Safety Engineering Chongqing UniversityChongqing 400030China Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Shenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Deep Underground Engineering Sciences and Green Energy College of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China

Fractal theory offers a powerful tool for the precise description and quantification of the complex pore structures in reservoir rocks,crucial for understanding the storage and migration characteristics of media within these *** with the challenge of calculating the three-dimensional fractal dimensions of rock porosity,this study proposes an innovative computational process that directly calculates the three-dimensional fractal dimensions from a geometric *** employing a composite denoising approach that integrates Fourier transform(FT)and wavelet transform(WT),coupled with multimodal pore extraction techniques such as threshold segmentation,top-hat transformation,and membrane enhancement,we successfully crafted accurate digital rock *** improved box-counting method was then applied to analyze the voxel data of these digital rocks,accurately calculating the fractal dimensions of the rock pore *** numerical simulations of permeability experiments were conducted to explore the physical correlations between the rock pore fractal dimensions,porosity,and absolute *** results reveal that rocks with higher fractal dimensions exhibit more complex pore connectivity pathways and a wider,more uneven pore distribution,suggesting that the ideal rock samples should possess lower fractal dimensions and higher effective porosity rates to achieve optimal fluid transmission *** methodology and conclusions of this study provide new tools and insights for the quantitative analysis of complex pores in rocks and contribute to the exploration of the fractal transport properties of media within rocks.

关键词： 3D fractal analysis Fractal dimension Rock pore structure Box-counting method Permeability simulation Computational geosciences

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Application of Optical Hydrogels in Environmental Sensing

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Energy & Environmental Materials 2024年第3期7卷 311-336页

作者： Shuo Yang Shruti Sarkar Xing xie Dan li Jianmin Chen Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention(LAP3) Department of Environmental Science and EngineeringFudan UniversityShanghai 200438China School of Civil and Environmental Engineering Georgia Institute of TechnologyAtlanta Georgia 30332USA

The ever-increasing complexity of environmental pollutants urgently warrants the development of new detection *** based on the optical properties of hydrogels enabling fast and easy in situ detection are attracting increasing *** this paper,the data from 138 papers about different optical hydrogels(OHs)are extracted for statistical *** detection performance and potential of various types of OHs in different environmental pollutant detection scenarios were evaluated and compared to those obtained using the standard detection *** on this analysis,the target recognition and sensing mechanisms of two main types of OHs are reviewed and discussed:photonic crystal hydrogels(PCHs)and fluorescent hydrogels(FHs).For PCHs,the environmental stimulus response,target receptors,inverse opal structures,and molecular imprinting techniques related to PCHs are reviewed and ***,the different types of fluorophores(i.e.,compound probes,biomacromolecules,quantum dots,and luminescent microbes)of FHs are ***,the potential academic research directions to address the challenges of applying and developing OHs in environmental sensing are proposed,including the fusion of various OHs,introduction of the latest technologies in various fields to the construction of OHs,and development of multifunctional sensor arrays.

关键词： environmental sensors fluorescent hydrogel optical hydrogel photonic crystal hydrogel pollution detection

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Tough lanthanide luminescent hydrogel for nitroaromatics detection

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Journal of Rare Earths 2024年第2期42卷 293-302,I0003页

作者： Shu xie Fei li Fengyi liu Quanqing Xu Xufeng Zhang College of Chemistry and Chemical Engineering Yunnan Normal UniversityKunming650092China

Luminescent hydrogels have received considerable attention in the application of *** matics are harmful to human health and can be *** skin allergies and central nervous system injuries may also be attributed to the over exposure to ***,nitroaromatics sensor with fast detection and low detection limit is highly ***,novel tough hydrogels were prepared by introducing hydrogen bonds and covalent bonds into the interpenetrating networks of modified chitosan and poly(vinyl alcohol)(PVA) via frozen-thawing induced chemical *** synthesized hydrogels exhibit high mechanical strength(0.23 MPa tensile strength at 140% tensile strain,1.0 MPa compressive strength at 80% compressive strain).Strong green emission was realized by energy transfer from the modified chitosan to Tb^(3+)via the so-called "antenna effect." The prepared luminescent hydrogels show an excellent detection effect on nitroaromatic compounds and its detection limit can reach *** hydrogels also exhibit good reversibility and a fast "off-on" fluorescence switching *** work may open up a new way for the development of stable,rapid,and reusable sensors for the detection of harmful nitroaromatics.

关键词： Hydrogels Lanthanide Luminescence Nitroaromatics Sensors Rare earths

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Resilience assessment and optimization method of city road network in the post-earthquake emergency period

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 765-779页

作者： Wang Haoran xiao Jia li Shuang Zhai Changhai Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information TechnologyHarbin Institute of TechnologyHarbin 150090China

The post-earthquake emergency period,which is a sensitive time segment just after an event,mainly focuses on saving life and restoring social *** improve the seismic resilience of city road networks,a resilience evaluation method used in the post-earthquake emergency period is *** road seismic damage index of a city road network can consider the influence of roads,bridges and buildings along the roads,*** road capacity after an earthquake.A function index for a city road network is developed,which reflects the connectivity,redundancy,traffic demand and traffic function of the *** optimization model for improving the road repair order in the post-earthquake emergency period is also developed according to the resilience evaluation,to enable decision support for city emergency management and achieve the best seismic resilience of the city road *** optimization model is applied to a city road network and the results illustrate the feasibility of the resilience evaluation and optimization method for a city road network in the post-earthquake emergency period.

关键词： city road network post-earthquake emergency period traffic demand resilience evaluation optimization model

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Price Masking Strategy of Cross-Border E-Commerce Platform Financing

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Journal of Systems Science & Complexity 2024年第2期37卷 668-691页

作者： li Jianbin HANG Zhouxin CHEN Zhiyuan xiao Shan School of Management Huazhong University of Science and TechnologyWuhan 430074China School of Economics and Management Wuhan UniversityWuhan 430072China

E-commerce platform financing is a new service pattern of supply chain ***,this pattern may bring some new issues when considering the problem of cash flow shortage and financing difficulties of small and medium-sized *** enterprises use this service,they worry about the leakage of preferential wholesale price when applying the full loan amount and providing the true transaction *** on the model consisting of a supplier,a retailer and a cross-border e-commerce platform,the authors design a price masking strategy to prevent the retailer’s preferential wholesale price information from *** authors analyze the profit of the retailer and the platform before and after adopting the price masking *** authors find that the price masking strategy always benefits the ***,the optimal profit of the retailer and the platform are both affected by the loan interest ***,there exists a range of loan interest rates that can benefit both the retailer and the platform if the price masking strategy is *** research emphasizes that platform can expand the total business volume by allowing retailers to use price masking *** other words,there will be more and more retailers attracted by the strategy,which benefits the long-term growth of cross-border e-commerce platform financing.

关键词： Cross-border e-commerce e-commerce platform financing price masking supply chain finance

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Distortion-aware beamforming design for multi-beam satellite communications with nonlinear power amplifiers

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Science China(Information Sciences) 2024年第6期67卷 359-369页

作者： Xiang xiao li YOU Kezhi WANG Xiqi GAO National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories Department of Computer Science Brunel University London

Hardware components can cause different impairments, including power amplifier(PA) nonlinearities, which inevitably impact the system performance of satellite communications(SATCOM). In this work, we consider a multi-beam SATCOM downlink system and investigate the distortion-aware beamforming scheme with the characteristics of PA non-linearities. Notably, we aim to maximize the resource efficiency(RE), defined as the weighted sum of energy efficiency(EE) with spectral efficiency(SE), to obtain a flexible EE-SE tradeoff while accounting for the characteristics of PA distortion and the total power *** that the optimization objective is a sum of ratios and the high non-convexity involved in constraints,we propose an efficient approach that exploits the quadratic transformation, the Lagrange multiplier method,and the gradient ascent approach to handle this issue. Simulation results demonstrate the effectiveness of the distortion-aware beamforming approach in achieving the EE-SE tradeoff and exhibit a substantial RE performance gain over the conventional approach with ideal linear PAs assumed at the satellite transmitters.

关键词： multi-beam satellite communications nonlinear power amplifier energy and spectral efficiency tradeoff resource efficiency robust beamforming

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Collision-free parking recommendation based on multi-agent reinforcement learning in vehicular crowdsensing

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Digital Communications and Networks 2024年第3期10卷 609-619页

作者： Xin li Xinghua Lei Xiuwen liu Hang xiao College of Computer Science and Technology China University of Petroleum(East China)QingDao266580China

The recent proliferation of Fifth-Generation(5G)networks and Sixth-Generation(6G)networks has given rise to Vehicular Crowd Sensing(VCS)systems which solve parking collisions by effectively incentivizing vehicle ***,instead of being an isolated module,the incentive mechanism usually interacts with other *** on this,we capture this synergy and propose a Collision-free Parking Recommendation(CPR),a novel VCS system framework that integrates an incentive mechanism,a non-cooperative VCS game,and a multi-agent reinforcement learning algorithm,to derive an optimal parking strategy in real ***,we utilize an LSTM method to predict parking areas roughly for recommendations *** incentive mechanism is designed to motivate vehicle participation by considering dynamically priced parking tasks and social network *** order to cope with stochastic parking collisions,its non-cooperative VCS game further analyzes the uncertain interactions between vehicles in parking *** its multi-agent reinforcement learning algorithm models the VCS campaign as a multi-agent Markov decision process that not only derives the optimal collision-free parking strategy for each vehicle independently,but also proves that the optimal parking strategy for each vehicle is ***,numerical results demonstrate that CPR can accomplish parking tasks at a 99.7%accuracy compared with other baselines,efficiently recommending parking spaces.

关键词： Incentive mechanism Non-cooperative VCS game Multi-agent reinforcement learning Collision-free parking strategy Vehicular crowdsensing

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Effect of oxide inclusions on MnS precipitates and tensile mechanical property of high-strength low-alloy steel

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Journal of Iron and Steel Research International 2024年第5期31卷 1210-1220页

作者： xiao-yong Gao Hong Wei li-feng Zhang School of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of Materials Science and Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing100144China

The key role of oxide inclusions on the microstructure and mechanical property of a high-strength low-alloy steel was *** field emission scanning electron microscope equipped with energy-dispersive spectrometry was used to characterize MnS *** inclusions play an important role in the shape control of MnS *** oxides fovored to decrease the size and the aspect ratio of MnS *** less oxide inclusions in the steel,approximately over 16.7%MnS precipitates were with aspect ratio a>5 and pure MnS precipitates accounted for 75.9%in ***,with more oxide inclusions in the steel,only 7.4%MnS precipitates were with a>5 and pure MnS precipitates accounted for 60.1%in *** of MnS by oxide inclusions improved the strength and inhibited the *** oxide inclusions in the steel increased the yield strength and tensile strength of the steel in both longitudinal and transverse directions,and lowered the anisotropy of the mechanical property.

关键词： High-strength low-alloy steel MnS Oxide inclusion Mechanical property Anisotropy

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Superconducting single-photon detector with a speed of 5 GHz and a photon number resolution of 61

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Photonics Research 2024年第6期12卷 1328-1333页

作者： TIANZHU ZHANG JIA HUANG XINGYU ZHANG CHAOMENG DING HUIQIN YU YOU xiao CHAOliN LV xiaoYU liU ZHEN WANG liXING YOU xiaoMING xie HAO li Shanghai Key Laboratory of Superconductor Integrated Circuit Technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Photon Technology(Zhejiang)Co. Ltd.Jiaxing 314100China

Rapid detection and discrimination of single photons are pivotal in various applications,such as deep-space laser communication,high-rate quantum key distribution,and optical quantum ***,conventional single-photon detectors(SPDs),including semiconducting and recently developed superconducting detectors,have limited detection speed and photon number resolution(PNR),which pose significant challenges in practical *** this paper,we present an efficient,fast SPD with good PNR,which has 64 paralleled,sandwiched superconducting nanowires fabricated on a distributed Bragg *** detector is operated in a compact Gifford–McMahon cryocooler that supports 64 electrical channels and has a minimum working temperature of 2.3 *** combined detector system shows a functional nanowire yield of 61/64,a system detection efficiency of 90%at 1550 nm,and a maximum count rate of 5.2 ***,it has a maximum PNR of 61,corresponding to the operating *** SPD signifies a substantial improvement in quantum detector technology,with potential applications in deep-space laser communication,high-speed quantum communication,and fundamental quantum optics experiments.

关键词： communication photon quantum

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A novel metal-free porous covalent organic polymer for efficient room-temperature photocatalytic CO2 reduction via dry-reforming of methane

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Green Energy & Environment 2024年第9期9卷 1407-1418页

作者： Sheng-Yan Yin Ziyi li Yingcai Hu xiao Luo Jishan li College of Chemistry and Chemical Engineering Hunan University Institute of Basic Medicine and Cancer (IBMC) Chinese Academy of Sciences

At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane（DRM） is quite promising and ***,we developed a novel covalent organic porous polymer （TPE-COP） with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature,which can efficiently generate syngas （CO and H2）.Both electron donor (tris（4-aminophenyl）amine,TAPA) and acceptor (4,4',4'',4'''-(（1 E,1'E,1''E,1'''E）-(ethene-1,1,2,2-tetrayltetrakis （benzene-4,1-diyl）)tetrakis （ethene-2,1-diyl）)tetrakis (1-（4-formylbenzyl）quinolin-1-ium),TPE-CHO) were existed in TPE-COP,in which the push–pull effect between them promoted the separation of photogenerated electron–hole,thus greatly improving the photocatalytic *** functional theory （DFT） simulation results show that TPE-COP can form charge-separating species under light irradiation,leading to electrons accumulation in TPE-CHO unit and holes in TAPA,and thus efficiently initiating *** 20 h illumination,the photocatalytic results show that the yields reach 1123.6 and 30.8μmol g-1for CO and H2,respectively,which are significantly higher than those of TPE-CHO small *** excellent result is mainly due to the increase of specific surface area,the enhancement of light absorption capacity,and the improvement of photoelectron-generating efficiency after the formation of ***,this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.

关键词： Metal-free Photocatalytic CO 2 reduction Covalent organic polymer Dry-reforming of methane Electron donor and acceptor

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