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A semi-analytical model for coupled flow in stress-sensitive multi-scale shale reservoirs with fractal characteristics

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Petroleum Science 2024年第1期21卷 327-342页

作者： Qian Zhang wen-Dong wang Yu-Liang Su Wei Chen Zheng-Dong lei lei Li Yong-Mao Hao Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Oil Development Branch Changqing Oilfield CompanyPetroChinaQingyang745708GansuChina PetroChina Research Institute of Petroleum Exploration&Development Beijing100083China

A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes due to stress sensitivity, which plays a crucial role in controlling pressure propagation and oil flow. This paper proposes a multi-scale coupled flow mathematical model of matrix nanopores, induced fractures, and hydraulic fractures. In this model, the micro-scale effects of shale oil flow in fractal nanopores, fractal induced fracture network, and stress sensitivity of multi-scale media are considered. We solved the model iteratively using Pedrosa transform, semi-analytic Segmented Bessel function, Laplace transform. The results of this model exhibit good agreement with the numerical solution and field production data, confirming the high accuracy of the model. As well, the influence of stress sensitivity on permeability, pressure and production is analyzed. It is shown that the permeability and production decrease significantly when induced fractures are weakly supported. Closed induced fractures can inhibit interporosity flow in the stimulated reservoir volume (SRV). It has been shown in sensitivity analysis that hydraulic fractures are beneficial to early production, and induced fractures in SRV are beneficial to middle production. The model can characterize multi-scale flow characteristics of shale oil, providing theoretical guidance for rapid productivity evaluation.

关键词： Multi-scale coupled flow Stress sensitivity Shale oil Micro-scale effect Fractal theory

High-Precision Doppler Frequency Estimation Based Positioning Using OTFS Modulations by Red and Blue Frequency Shift Discriminator

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China Communications 2024年第2期21卷 17-31页

作者： Shaojing wang Xiaomei Tang Jing lei Chunjiang Ma Chao wen Guangfu Sun School of Electronic Science National University of Defense TechnologyChangsha 410073China

Orthogonal Time Frequency and Space(OTFS) modulation is expected to provide high-speed and ultra-reliable communications for emerging mobile applications, including low-orbit satellite communications. Using the Doppler frequency for positioning is a promising research direction on communication and navigation integration. To tackle the high Doppler frequency and low signal-to-noise ratio(SNR) in satellite communication, this paper proposes a Red and Blue Frequency Shift Discriminator(RBFSD) based on the pseudo-noise(PN) *** paper derives that the cross-correlation function on the Doppler domain exhibits the characteristic of a Sinc function. Therefore, it applies modulation onto the Delay-Doppler domain using PN sequence and adjusts Doppler frequency estimation by red-shifting or blue-shifting. Simulation results show that the performance of Doppler frequency estimation is close to the Cramér-Rao Lower Bound when the SNR is greater than -15dB. The proposed algorithm is about 1/D times less complex than the existing PN pilot sequence algorithm, where D is the resolution of the fractional Doppler.

关键词： channel estimation communication and navigation integration Orthogonal Time Frequency and Space pseudo-noise sequence red-blue frequency shift discriminator

Westerlies Affecting the Seasonal Variation of Water Vapor Transport over the Tibetan Plateau Induced by Tropical Cyclones in the Bay of Bengal

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Advances in Atmospheric Sciences 2024年第5期41卷 881-893页

作者： Xiaoli ZHOU wen ZHOU Dongxiao wang Qiang XIE lei YANG Qihua PENG Key Laboratory of Polar Atmosphere-ocean-ice System for Weather and Climate Ministry of Education&Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric SciencesFudan UniversityShanghai 200438China School of Marine Sciences Sun Yat-Sen UniversityZhuhai 519082China Institute of Deep-sea Science and Engineering Chinese Academic SciencesSanya 572000China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academic ScienceGuangzhou 510301China Scripps Institution of Oceanography University of CaliforniaSan DiegoLa JollaCalifornia 92093USA

This study investigates the activity of tropical cyclones(TCs)in the Bay of Bengal(BOB)from 1979 to 2018 to discover the mechanism affecting the contribution rate to the meridional moisture budget anomaly(MMBA)over the southern boundary of the Tibetan Plateau(SBTP).May and October–December are the bimodal phases of BOB TC frequency,which decreases month by month from October to December and is relatively low in ***,the contribution rate to the MMBA is the highest in *** seasonal variation in the meridional position of the westerlies is the key factor affecting the contribution *** relatively southern(northern)position of the westerlies in November and December(May)results in a lower(higher)contribution rate to the *** mechanism is confirmed by the momentum *** water vapor enters the westerlies near the trough line,the resultant meridional acceleration is directed *** follows that the farther north the trough is,and the farther north the water vapor can be *** water vapor enters the westerlies from the area near the ridge line,for Type-T(Type-R)TCs,water vapor enters the westerlies downstream of the trough(ridge).Consequently,the direction of the resultant meridional acceleration is directed south and the resultant zonal acceleration is directed east(west),which is not conducive to the northward transport of water *** is especially the case if the trough or ridge is relatively south,as the water vapor may not cross the SBTP.

关键词： tropical cyclone Tibetan Plateau Bay of Bengal moisture budget weste

Divergent defluorocarboxylation of α-CF_(3) alkenes with formate via photocatalyzed selective mono-or triple C-F bond cleavage

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Science China Chemistry 2024年第1期67卷 368-373页

作者： Xing-Yu wang Pei Xu wen-wen Liu Hao-Qiang Jiang Song-lei Zhu Dong Guo Xu Zhu Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy School of PharmacyXuzhou Medical UniversityXuzhou 22100China

Unprecedented divergent synthesis of gem-difluorovinylacetic acid and glutaric acid derivatives fromα-CF_(3)alkenes with formate as the carbonyl source was *** reaction can undergo selective mono-or triple C-F bond cleavage by simply switching the photocatalyst and hydrogen atom transfer(HAT)catalyst under visible-light-induced conditions at room *** acts as both the C1 source and the reductant through the generation of CO_(2)^(·-)species,which underwent Giese radical addition to electron-deficient alkenes to trigger the consecutive C-F bond cleavage and carboxylation process.

关键词： C-F bond activation defluorocarboxylation carbon dioxide radical anion visible light

A thermo-responsive rewritable plasmonic bio-memory by regulating single core-satellite gold nanocluster dissociation

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Nano Research 2024年第8期17卷 7275-7282页

作者： wen Zhang Yi wang Yamin wang Xiaomei Lu Weibing Wu Quli Fan lei Zhang State Key Laboratory of Organic Electronics and Information Displays&Institute of Advanced Materials(IAM) Nanjing University of Posts&TelecommunicationsNanjing 210023China Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources College of Light Industry and Food EngineeringNanjing Forestry UniversityNanjing 210037China Zhengzhou Institute of Biomedical Engineering and Technology Zhengzhou 450001China Key Laboratory of Flexible Electronics(KLOFE) Institute of Advanced Materials(IAM)&School of Flexible Electronics(Future Technologies)Nanjing Tech University(Nanjing Tech)Nanjing 211816China

A thermo-responsive rewritable plasmonic bio-memory chip has been successfully fabricated on an indium tin oxide(ITO)glass slide by assembling core-satellite gold nanoclusters with different size of gold nanoparticles(AuNPs)using double-strand DNA(dsDNA)*** the prepared 70@DNA20@13 gold nanoclusters(AuNCs)exhibited more stable and greater photothermal conversion *** short time irradiation by 633 nm microbeam laser,every individual AuNCs could be excited and remove the satellite AuNPs on its ***,in the dissociation process of AuNCs with 3−5 satellite,its color would change from yellow to green,which showed more significant reduction in the red channel of the dark-field microscopy(DFM)images and could be defined to state“0”and“1”***,this plasmonic nano bio-memory could transform cyclically its state between 0 and 1 which exhibited excellent rewritable ability.

关键词： plasmonic assembly thermal-responsive single nanoparticle rewritable bio-memory

Black holes as the source of dark energy:A stringent test with high-redshift JWST AGNs

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 181-188页

作者： lei lei lei Zu Guan-wen Yuan Zhao-Qiang Shen Yi-Ying wang Yuan-Zhu wang Zhen-Bo Su wen-Ke Ren Shao-Peng Tang Hao Zhou Chi Zhang Zhi-Ping Jin lei Feng Yi-Zhong Fan Da-Ming Wei Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China

Studies have proposed that there is evidence for cosmological coupling of black holes(BHs)with an index of k≈3;hence,BHs serve as the astrophysical source of dark ***,the data sample is limited for the redshifts of≤*** recent years,the James Webb Space Telescope(JWST)has detected many high-redshift active galactic nuclei(AGNs)and *** the JWST NIRSpec-/NIRCam-resolved AGNs,three are determined to be in early-type host galaxies with a redshift of z~***,their M_(*)and MBH are in tension with the predicted cosmological coupling of black holes with k=3 at a confidence level of~2σ,which challenges the hypothesis that BHs serve as the origin of dark *** work on high-redshift AGNs using the JWST will further assess such a hypothesis by identifying more early-type host galaxies in the higher mass range.

关键词： dark energy supermassive black hole active galactic nuclei James Webb Space Telescope

Bimetallic NiCoP catalysts anchored on phosphorus-doped lignin-based carbon for robust oxygen evolution performance

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Rare Metals 2024年第7期43卷 3084-3095页

作者： Ling-Ying-Zi Xiong Bo-wen Liu lei Du Yue-Kuan Zhou Xu-Liang Lin Huan wang Guangdong Engineering Technology Research Center for Sensing Materials&Devices Guangzhou Key Laboratory of Sensing Materials&DevicesSchool of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou 510006China School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center Jieyang 515200China Sustainable Energy and Environment Thrust Function HubThe Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China Division of Emerging Interdisciplinary Areas Department of Mechanical and Aerospace EngineeringThe Hong Kong University of Science and TechnologyHong Kong 999077China State Key Lab of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510640China

Oxygen evolution reaction(OER)catalysts are the key core materials that determine the performance of fuel cells,metal-air batteries,electrolytic water decomposition,and other *** this work,a green lignin-based non-precious metal OER catalyst was prepared by a simple ***,c arboxylated lignin was used to complex Ni and Co in situ,and then they were placed with sodium hypophosphite in the same tube furnace for upstream and downstream high-temperature calcination to construct a lignin carbon-based Ni-Co bimetallic OER catalyst(NiCoP@C).The synthesized catalyst is a porous bimetallic phosphide with a three-dimensional network structure and high-density electrochemical active ***@C exhibited favorable catalytic activity for the oxygen evolution reaction(OER)with overpotential of 280 mV at 10 mA·cm~(-2)and a Tafel slope of 77 mV·dec~(-1).Additionally,it exhibited remarkable durability during *** functional theory(DFT)calculations revealed that by leveraging the distinctive structure of transition metal phosphide nanoparticles incorporated into a reticulated substrate,the NiCoP@C catalyst offered an increased number of active sites for OER catalysis,significantly enhancing its stability during practical *** present study broadens the utilization pathways of biomass to"turn waste into treasure,"aligning the development concept of green sustainable development.

关键词： Oxygen evolution reaction Lignin Carbon-based catalyst Nickel-cobalt bimetal Metal phosphide

Two-Stage Online Debiased Lasso Estimation and Inference for High-Dimensional Quantile Regression with Streaming Data

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Journal of Systems Science & Complexity 2024年第3期37卷 1251-1270页

作者： PENG Yanjin wang lei School of Statistics and Data Science KLMDASRLEBPS and LPMCNankai UniversityTianjin 300071China

In this paper,the authors propose a two-stage online debiased lasso estimation and statistical inference method for high-dimensional quantile regression(QR)models in the presence of streaming *** the first stage,the authors modify the QR score function based on kernel smoothing and obtain the online lasso smoothed QR estimator through iterative *** estimation process only involves the current data batch and specific historical summary statistics,which perfectly accommodates to the special structure of streaming *** the second stage,an online debiasing procedure is carried out to eliminate biases caused by the lasso penalty as well as the accumulative approximation error so that the asymptotic normality of the resulting estimator can be *** authors conduct extensive numerical experiments to evaluate the performance of the proposed *** experiments demonstrate the effectiveness of the proposed method and support the theoretical *** application to the Beijing PM2.5 Dataset is also presented.

关键词： Adaptive tuning asymptotic normality debiased lasso online updating quantile regres-sion

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Physical mechanism of the rapid increase in intense and long-lived extreme heatwaves in the Northern Hemisphere since 1980

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Science China Earth Sciences 2024年第7期67卷 2103-2121页

作者： Yuqing wang wen ZHOU Chunzai wang Key Laboratory of Polar Atmosphere-ocean-ice System for Weather and Climate of the MOE Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric SciencesFudan UniversityShanghai 200438China Key Laboratory for Polar Science of the MNR Polar Research Institute of ChinaShanghai 201209China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Global Ocean and Climate Research Center South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China

Since 1980,both the intensity and duration of summer heatwaves in the middle and high latitudes of the Northern Hemisphere have significantly increased,leading this region to become a critical area for a significant increase in the frequency of intense and long-lived extreme *** found that stronger and more persistent high-pressure systems and lower soil moisture before the events were the main drivers of intense and long-lived extreme heatwaves in western Europe and the middle and high latitudes of North ***,in eastern Europe and Siberia,lower cloud cover before events is also a main driver of this type of extreme heatwave,in addition to the above *** factors are coupled with each other and can change heatwave intensity and duration by influencing surface radiation processes during *** the self-organizing map classification method,we found that 6 weather patterns with increased frequency,intensity,and duration were the main dynamic reasons leading to the increase in intense and long-lived extreme heatwaves after *** addition,the decrease in summer average soil moisture in most areas of the mid-high latitudes of the Northern Hemisphere and the decrease in average cloud cover in eastern Europe and Siberia are found to be the main thermodynamic reasons leading to the increase in these extreme heatwaves.

关键词： High intensity Long duration Extreme heatwaves High pressure system Soil moisture Cloud cover

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