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Integrated wellbore-reservoir-geomechanics modeling for enhanced interpretation of distributed fiber-optic strain sensing data in hydraulicfracture analysis

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3136-3148页

作者： Lijun Liu Xinglin guo Xiaoguang wang State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China Tianfu Yongxing Laboratory Chengdu610213China College of Energy Chengdu University of TechnologyChengdu610059China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu610059China

Fiber-optic distributed strain sensing(FO-DSS)has been successful in monitoring strain changes along horizontal wellbores in hydraulically fractured ***,the mechanism driving the various FO-DSS responses associated with near-wellbore hydraulic fracture properties is still *** address this knowledge gap,we use coupled wellbore-reservoir-geomechanics simulations to study measured strain-change behavior and infer hydraulic fracture *** crossflow among fractures is captured through explicit modeling of the transient wellbore *** addition,local grid refinement is applied to accurately capture strain changes along the fiber.A Base Case model was designed with four fractures of varying properties,simulating strain change signals when the production well is shut-in for 10 d after 240 d of production and reopened for 2 ***-pressure plots for different fracture clusters were used to gain insights into inferring fracture properties using DSS *** comparing the model with and without the wellbore,distinct strain change signals were observed,emphasizing the importance of incorporating the wellbore in FO-DSS *** effects of fracture spacing and matrix permeability on strain change signals were thoroughly *** results of our numerical study can improve the understanding of the relation between DSS signals and fracture hydraulic properties,thus maximizing the value of the dataset for fracture diagnostics and characterization.

关键词： Distributed strain sensing Fracture diagnostic Coupled flow and geomechanics Transient wellbore flow

Differentially private SGD with random features

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 1-23页

作者： wang Yi-guang guo Zheng-chu Polytechnic Institute of Zhejiang University Zhejiang UniversityHangzhou 310015China School of Mathematical Sciences Zhejiang UniversityHangzhou 310058China

In the realm of large-scale machine learning,it is crucial to explore methods for reducing computational complexity and memory demands while maintaining generalization ***,since the collected data may contain some sensitive information,it is also of great significance to study privacy-preserving machine learning *** paper focuses on the performance of the differentially private stochastic gradient descent(SGD)algorithm based on random *** begin,the algorithm maps the original data into a lowdimensional space,thereby avoiding the traditional kernel method for large-scale data storage ***,the algorithm iteratively optimizes parameters using the stochastic gradient descent ***,the output perturbation mechanism is employed to introduce random noise,ensuring algorithmic *** prove that the proposed algorithm satisfies the differential privacy while achieving fast convergence rates under some mild conditions.

关键词： learning theory differential privacy stochastic gradient descent random features reproducing kernel Hilbert spaces

Promotion effect of epoxy group neighboring single-atom Cu site on acetylene hydrochlorination

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Chinese Chemical Letters 2024年第6期35卷 258-262页

作者： Junchen Peng Xue Yin Dandan dong Zhongyuan guo Qinqin wang Minmin Liu Fei He Bin Dai Chaofeng Huang School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering Shihezi UniversityShihezi 832000China College of Chemistry&Chemical Engineering Yantai UniversityYantai 264010China School of Material Science and Engineering University of JinanJi’nan 250022China

Carbon materials have been used as the support for catalysts in the field of acetylene hydrochlorination,the influence of inevitable oxygen-containing moieties on the reaction is often ignored and the mechanism of the oxygen-doping structure remains ***,we explored the effect of the oxygen-containing group(C-O-C)in the support on the activity of single-atom dispersed Cu *** immersing the Cu single-atom catalyst in an alkaline solution,the epoxy species on the carbon support was cleaved to obtain a pure ether species while the Cu site was modified to a more electron-deficient *** turnover frequency value of Cu/O-FLP catalyst with epoxy groups was 1.6-fold higher than that of alkaline treated *** result indicated that the epoxy groups could assist adjacent single-atom Cu sites to synergistically promote the adsorption and cleavage of the reactant hydrogen chloride toward form C-OH and Cu-Cl bonds,and reduce the reaction energy *** presence of electron deficient Cu sites and ether species could induce competitive adsorption of the acetylene and hydrogen chloride,thereby reducing the activity of the *** study highlights the influence of surface oxygen species and the tunability of the support,providing the foundation for the fabrication of higher-activity Cu catalysts for acetylene hydrochlorination.

关键词： Epoxy group Acetylene hydrochlorination Single-atom Cu catalyst Synergistic dissociation

Reinforcement Learning-Based Dynamic Order Recommendation for On-Demand Food Delivery

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Tsinghua Science and Technology 2024年第2期29卷 356-367页

作者： Xing wang Ling wang Chenxin dong Hao Ren Ke Xing Department of Automation Tsinghua UniversityBeijing 100080China School of Mechanical and Automotive Engineering Qingdao Hengxing University of Science and TechnologyQingdao 266100China Meituan Beijing 100015China

On-demand food delivery(OFD)is gaining more and more popularity in modern *** a kernel order assignment manner in OFD scenario,order recommendation directly influences the delivery efficiency of the platform and the delivery experience of *** paper addresses the dynamism of the order recommendation problem and proposes a reinforcement learning solution *** actor-critic network based on long short term memory(LSTM)unit is designed to deal with the order-grabbing conflict between different ***,three rider sequencing rules are accordingly proposed to match different time steps of the LSTM unit with different *** test the performance of the proposed method,extensive experiments are conducted based on real data from Meituan delivery *** results demonstrate that the proposed reinforcement learning based order recommendation method can significantly increase the number of grabbed orders and reduce the number of order-grabbing conflicts,resulting in better delivery efficiency and experience for the platform and riders.

关键词： on-demand food delivery order recommendation reinforcement learning actor-critic network long short term memory

Cooperation between single atom catalyst and support to promote nitrogen electroreduction to ammonia:A theoretical insight

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Journal of Energy Chemistry 2024年第9期96卷 336-344页

作者： Wanying guo Siyao wang Hongxia wang Qinghai Cai Jingxiang Zhao College of Chemistry and Chemical Engineering Harbin Normal UniversityHarbin 150025HeilongjiangChina

The co-catalysis between single atom catalyst(SAC)and its support has recently emerged as a promising strategy to synergistically boost the catalytic activity of some complex electrochemical reactions,encompassing multiple intermediates and ***,we utilized defective BC_(3)monolayer-supported SACs as a prototype to investigate the cooperative effects of SACs and their support on the catalytic performance of the nitrogen reduction reaction(NRR)for ammonia(NH_(3))*** results showed that these SACs can be firmly stabilized on these defective BC_(3)supports with high stability against ***,co-activation of the inert N_(2)reactant was observed in certain embedded SACs and their neighboring B atoms on certain BC3 sheets due to the noticeable charge transfer and significant N–N bond *** high-throughput screening revealed that the Mo/DV_(CC)and W/DV_(CC)exhibit superior NRR catalytic performance,characterized by a low limiting potential of−0.33 and−0.43 V,respectively,which can be further increased under acid conditions based on the constant potential ***,varying NRR catalytic activities can be attributed to the differences in the valence state of active ***,further microkinetic modeling analysis displayed that the turnover frequency of N_(2)–to–NH_(3)conversion on Mo/DV_(CC)is as large as 1.20×10^(−3)s^(−1)site^(−1) at 700 K and 100 bar,thus guaranteeing its ultra-fast reaction *** results not only suggest promising advanced electrocatalysts for NRR but also offer an effective avenue to regulate the electrocatalytic performance via the co-catalytic metal–support interactions.

关键词： Co-catalysis Single atom catalyst Nitrogen reduction DFT computations

Adaptive multi-channel Bayesian graph attention network for IoT transaction security

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Digital Communications and Networks 2024年第3期10卷 631-644页

作者： Zhaowei Liu dong Yang Shenqiang wang Hang Su School of Computer and Control Engineering Yantai UniversityYantai264005China Department of Electronics Information and BioengineeringPolitecnico di MilanoMilan20133Italy

With the rapid advancement of 5G technology,the Internet of Things(IoT)has entered a new phase of appli-cations and is rapidly becoming a significant force in promoting economic *** to the vast amounts of data created by numerous 5G IoT devices,the Ethereum platform has become a tool for the storage and sharing of IoT device data,thanks to its open and tamper-resistant ***,Ethereum account security is necessary for the Internet of Things to grow quickly and improve people's *** modeling Ethereum trans-action records as a transaction network,the account types are well identified by the Ethereum account classifi-cation system established based on Graph Neural Networks(GNNs).This work first investigates the Ethereum transaction ***,experimental metrics reveal that the Ethereum transaction network is neither optimal nor even satisfactory in terms of accurately representing transactions per *** flaw may significantly impede the classification capability of GNNs,which is mostly governed by their *** work proposes an Adaptive Multi-channel Bayesian Graph Attention Network(AMBGAT)for Ethereum account clas-sification to address this *** uses attention to enhance node features,estimate graph topology that conforms to the ground truth,and efficiently extract node features pertinent to downstream *** extensive experiment with actual Ethereum transaction data demonstrates that AMBGAT obtains competitive performance in the classification of Ethereum accounts while accurately estimating the graph topology.

关键词： Internet of things Graph representation learning Node classification Security mechanism

Study on the force chain characteristics with coal dust layer and the three-body contact stiffness

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Particuology 2024年第9期92卷 288-304页

作者： Xinwei Yang dongxuan Wu Hongyue Chen dong wang School of Mechanical Engineering Liaoning Technical UniversityFuxin123000China Ordos Institute of Liaoning Technical University Ordos017000China School of Mining Liaoning Technical UniversityFuxin123000China China National Coal Association Dynamic Research for High-end Complete Integrated Coal Mining Equipment and Big Data Analysis CentreFuxin123000China

To explore the influence of the meso-mechanical behaviors of the wet coal dust layers on the contact stiffness of mechanical bonding surfaces,a three-body contact model incorporating an interface with wet coal dust was constructed based on breakage *** model considered the mechanical surface morphology and contact characteristics of the wet coal *** force chain evolution laws of the wet coal dust layer were elucidated under the effects of gap filling and the cover layer,and the bearing characteristics of the three-body contact bonding surfaces were revealed by quantitative analyses of the number,length,collimation coefficient,and coordination number of the force chains within the wet coal dust ***,the three-body normal contact stiffness under various preload forces was computed and experimentally *** results demonstrate that the external load transfer path of the three-body contact bonding surfaces was from mechanical surface(macroscopic stress)to wet coal dust layer(mesoscopic force chains)and then to mechanical surface(peaks and valleys).The interactions among these three elements contributed to transforming the distributions of the macroscopic stresses and mesoscopic force chains to the locations at the peaks and valleys of the mechanical *** them,the proportion of short force chains in the wet coal dust layer increased from approximately 0.8%–91%,while the proportion of long force chains exhibited an opposite changing *** force chain collimation coefficient initially increased and subsequently stabilized,reaching a maximum value of 0.93.A large number of broken,small particles in the wet coal dust layer mainly served to fill the gaps among large *** maximum relative error between the experimental and simulated values on the three-body contact stiffness is 7.26%,indicating that the simulation results can be an approximate substitute for the experimental results with a certain degree of accuracy and practic

关键词： Wet coal dust Force chain Three-body contact stiffness Gap flling effect Cover layer effect

Microstructure and property of laser additive manufactured alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si after aged at different temperatures

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Rare Metals 2024年第5期43卷 2275-2281页

作者： guo-Chao Li Xu Cheng Hua-Ming wang National Engineering Laboratory of Additive Manufacturing for Large Metallic Components and Engineering Research Center of Ministry of Education on Laser Direct Manufacturing for Large Metallic Components School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar *** this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was *** results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' *** at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine *** increasing the aging temperature,the number of α_(s) decreases but with coarsened *** aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°*** changing size of α_(s) obviously influences the property of the *** fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.

关键词： α+βtitanium alloy Laser additive manufacturing Solid solution and aging treatment Microstructure Room temperature tensile property

No Incidence of Liver Cancer Was Observed in A Retrospective Studyof Patients with Aristolochic Acid Nephropathy

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Chinese Journal of Integrative Medicine 2024年第2期30卷 99-106页

作者： SU Tao FANG Zhi-e guo Yu-ming wang Chun-yu wang Jia-bo JI dong BAI Zhao-fang YANG Li XiAO Xiao-he Renal Division Department of MedicinePeking University First HospitalBeijing(100034)China Department of Pharmacy Chongqing Hospital of Traditional Chinese MedicineChongqing(400021)China Department of Hepatology Fifth Medical Center of Chinese PLA General HospitalBeijing(100039)China China Military Institute of Chinese Materia Fifth Medical Center of Chinese PLA General HospitalBeijing(100039)China Phase I Clinical Trials Unit Department of Medicine for Infectious DiseasesFifth Medical Center of Chinese PLA General HospitalBeijing(100039)China Department of Pharmacy Affiliated Hospital of Shandong University of Traditional Chinese MedicineJinan(250000)China National Key Laboratory of Kidney Diseases Beijing(100039)China

Objective:To assess the risk of aristolochic acid(AA)-associated cancer in patients with AA nephropathy(AAN).Methods:A retrospective study was conducted on patients diagnosed with AAN at Peking University First Hospital from January 1997 to December ***-term surveillance and follow-up data were analyzed to investigate the influence of different factors on the prevalence of *** primary endpoint was the incidence of liver cancer,and the secondary endpoint was the incidence of urinary cancer during 1 year after taking AA-containing medication to ***:A total of 337 patients diagnosed with AAN were included in this *** the initiation of taking AA to the termination of follow-up,39 patients were diagnosed with *** cases of liver cancer were observed throughout the entire follow-up period,with urinary cancer being the predominant type(34/39,87.17%).Logistic regression analysis showed that age,follow-up period,and diabetes were potential risk factors,however,the dosage of the drug was not significantly associated with urinary ***:No cases of liver cancer were observed at the end of ***,a high prevalence of urinary cancer was observed in AAN *** a direct causality between AA and HCC is challenging.

关键词： aristolochic acid hepatocellular carcinoma urinary cancer drug safety retrospective study