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

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Sc.ence 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 Sc.ence 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

Tuning interfacial charge transfer for effic.ent visible-light-driven photodegradation and simultaneous H_(2)evolution

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Journal of Materials Sc.ence & Technology 2024年第1期168卷 35-49页

作者： Zhiyang Li Yaogang c.en Yinghe Zhang Wei Ai Qian lei Tingjun Yao Dan Zhong Wenjie Liu Wenbiao Jin lei Yang State Key Laboratory of Urban Water Resource and environment Shenzhen Key Laboratory of Organic Pollution Prevention and ControlSchool of Civil and Environmental EngineeringHarbin Institute of Technology ShenzhenShenzhen 518055China Key Laboratory of Northwest Water Resources Environment and EcologyMinistry of EducationSchool of Environmental and Municipal EngineeringXi’an University of Architecture and TechnologyXi’an 710055China cNAS Accredited Test center Guangdong Engineering Technology Research Center of Air PurificationHealthlead Co.Ltd.Shenzhen 518055China School of Sc.ence Harbin Institute of Technology ShenzhenShenzhen 518055China

The edge-graphitized carbon nitride(c_(3)N_(4)-c g)was prepared by secondary pyrolysis to construct ZnO/c_(3)N_(4)-c g(ZcN)type-Ⅱheterojunction photocatalyst via a facile sonication dispersion method,which achieved∼7.04-fold and∼18.3-fold enhanced visible-light-driven photocatalytic performance for refrac-tory micropollutant removal and simultaneous hydrogen(H_(2))evolution respectively compared to con-ventional ZnO/g-c_(3)N_(4)Step-scheme *** apparent quantum effic.ency of the ZcN_(0.4)het-erojunction reaches 0.92%(λ=420 nm).Such excellent performance stems from that the edge-graphene moieties stitched onto the interface of heterojunction extend light absorption to the full visible spec-trum,meanwhile,the built-in electric field generated during Fermi level alignment accompanying fa-vorable band-bending structure provides an effective pathway for the rapid migration of photoinduced electrons via the edge graphene channel to improve interfacial charge separation ***,the midgap states introduced in ZcN heterojunction could temporarily retain photoexcited electrons to effectively inhibit the in situ carrier recombination for improved photocatalytic H_(2)***,ZcN/peroxymonosulfate system exhibited excellent anti-interference performance against complex water bodies under visible illumination due to the synergistic effect between the co-existing anions and organic ***,the eco-friendly nature of the ZcN/peroxymonosulfate system showed no biotoxicity of reaction filtrate on cell proliferation after treatment,which avoided secondary ***-ering the outstanding performance in photocatalysis,the ZcN system exhibits broad potential for practical applications in water pollution control and green energy production.

关键词： ZnO c_(3)N_(4)-c g Heterojunction Photodegradation Hydrogen evolution

Inter-stage performance and energy characteristics analysis of electric submersible pump based on entropy production theory

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Petroleum Sc.ence 2024年第2期21卷 1354-1368页

作者： Hui Wang Yang Yang Bin Xi Wei-Dong Shi chuan Wang lei-lei Ji Xiang-Yu Song Zhao-Ming He college of Hydraulic Sc.ence and engineering Yangzhou UniversityYangzhou225009JiangsuChina college of Electrical and Mechanical engineering Nanchang Institute of TechnologyNanchang330044JiangxiChina college of Mechanical engineering Nantong UniversityNantong226019JiangsuChina National Research center of Pumps Jiangsu UniversityZhenjiang212013JiangsuChina Zhejiang Zhenxing Petrochemical Machinery co. Ltd.Ruian325204ZhejiangChina Department of Mechanical engineering of Texas Tech University Lubbock79411TXUSA

The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction *** lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional effic.ency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.

关键词： Electric submersible pump(ESP) entropy production theory energy characteristics Inter-stage differences

Influence of Film Thickness on Nanofabrication of Graphene Oxide

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Nanomanufacturing and Metrology 2024年第2期7卷 13-25页

作者： chuan Tang lei c.en Linmao Qian Tribology Research Institute The State Key Laboratory of Rail Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and ***,we examined the effects of graphene oxide(GO)film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope *** material removal of GO initiates at the load above a critical value,which strongly depends on film thickness and *** the increase in film thickness,the critical load decreases monotonically on the plane surfaces but increases gradually at the step ***,the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces,and the gap decreases to around 3 times when GO thickness increases to four ***,mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 ***,the GO nanostructures are deoxidized by annealing at 800°c in high-purity argon to restore their highly functionalized conjugated structures,which are supported by X-ray diffraction and Raman *** work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication,which holds significant potential for applications in graphene-based devices.

关键词： Graphene oxide Nanofabrication Film thickness step edge Nanopattern Deoxidized treatment

Investigating the Effects of V2c MXene on Improving the Switching Stability and Reducing the Operation Voltages of TiO2-Based Memristors

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chinese Journal of Electronics 2024年第5期33卷 1181-1187页

作者： Nan HE lei WANG Yi TONG college of Electronic and Optical engineering College of Flexible Electronics (Future Technology) and College of Integrated Circuit Science and Engineering Nanjing University of Posts and Telecommunications Gusu Laboratory of Materials

Three-atoms-type V2c MXene, an emerging class of transition metal carbides, has attracted tremendous attention in the fabrication of advanced memristive devices due to its excellent electrochemical properties. However,the inserted effects and corresponding physical mechanisms of inserting V2c on traditional TiO2-based memristors have not been clearly explored. In this work, exhaustive electrical characterizations of the V2c/TiO2-based devices exhibit enhanced performance（e.g., improved switching stability and lower operating voltages） compared to the TiO2-based counterparts. In addition, the advantaged influences of the inserted V2c have also been studied by means of first-principles calculations, confirming that V2c MXene enables controllable internal ionic process and facilitated formation mechanism of the Ag conductive filaments. This work demonstrates a way to combine experimental and theoretical investigations to reveal the positive effects of introducing V2c MXene on memristor, which is beneficial for fabricating performance-enhanced memristors.

关键词： Performance evaluation Fabrication Memristors Process control Metals Switches Stability analysis Memristor V2c MXene First-principles calculation Switching stability Formation mechanism

New Algebraic Attacks on Grendel with the Strategy of Bypassing SPN Steps

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chinese Journal of Electronics 2024年第3期33卷 635-644页

作者： Wenxiao QIAO Siwei SUN lei HU State Key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences School of cyber Security University of Chinese Academy of Sciences School of cryptology University of Chinese Academy of Sciences State Key Laboratory of cryptology

The rapid development of modern cryptographic applications such as zero-knowledge,secure multiparty computation,fully homomorphic.encryption has motivated the design of new so-called arithmetization-oriented symmetric *** designing ciphers in this domain is relatively new and not well-understood,the security of these new ciphers remains to be completely *** this paper,we revisit the security analysis of arithmetizat ionoriented cipher *** uses the Legendre symbol as a component,which is tailored specifically for the use in zero-knowledge and effic.ently-varifiable proof *** FSE 2022,the first preimage attack on some original full GrendelHash instances was *** a countermeasure,the designer adds this attack into the security analysis and updates the formula to derive the secure number of *** our work,we present new algebraic attacks on *** the preimage attack,we can reduce the complexity or attack one more round than previous attacks for some *** addition,we present the first collision attack on some round-reduced instances by solving the constrained input/constrained output problem for the underlying permutations.

关键词： ciphers Symbols Multi-party computation complexity theory Homomorphic.encryption

A Denoiser for correlated Noise channel Decoding: Gated-Neural Network

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china communications 2024年第2期21卷 122-128页

作者： Xiao Li Ling Zhao Zhen Dai Yonggang lei School of Electronic and Information engineering Beihang UniversityBeijing 100191China Beijing Institute of Tracking and Telecommunications Technology BITTT

This letter proposes a sliced-gated-convolutional neural network with belief propagation(SGcNN-BP) architecture for decoding long codes under correlated noise. The basic idea of SGcNNBP is using Neural Networks(NN) to transform the correlated noise into white noise, setting up the optimal condition for a standard BP decoder that takes the output from the NN. A gate-controlled neuron is used to regulate information flow and an optional operation—slicing is adopted to reduce parameters and lower training complexity. Simulation results show that SGcNN-BP has much better performance(with the largest gap being 5dB improvement) than a single BP decoder and achieves a nearly 1dB improvement compared to Fully convolutional Networks(FcN).

关键词： belief propagation channel decoding correlated noise neural network

Evidence of guide field magnetic reconnection in flapping current sheets

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Earth and Planetary Physics 2024年第4期8卷 650-658页

作者： YunTian Hou SuPing Duan lei Dai chi Wang State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China college of Earth and Planetary Sc.ences University of Chinese Academy of SciencesBeijing 100049China

Based on current sheet flapping motion on 27 August 2018 in the dusk flank magnetotail,as recorded by instruments aboard Magnetospheric Multiscale(MMS)spacecraft,we present the first study of guide field reconnection observed in the flux rope embedded in kink-like flapping current sheets near the dusk-side flank of the *** more common magnetotail reconnections,which are symmetric,these asymmetric small-scale(λ_(i)~650 km)reconnections were found in the highly twisted current sheet when the direction normal to the sheet changes from the Z direction into the Y *** unique feature of this unusual reconnection is that the reconnection jets are along the Z direction-different from outflow in the X direction,which is the more usual *** vertical reconnection jet is parallel or antiparallel to the up-and-down motion of the tail’s current *** normalized reconnection rate R is estimated to be~*** results indicate that such asymmetric reconnections can significantly enlarge current sheet flapping,with large oscillation *** letter presents direct evidence of guide field reconnection in a highly twisted current sheet,characterized by enlarged current sheet flapping as a consequence of the reconnection outflow.

关键词： magnetic reconnection magnetotail current sheet

A stable implicit nodal integration-based particle finite element method(N-PFEM)for modelling saturated soil dynamics

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 2172-2183页

作者： Liang Wang Xue Zhang Jingjing Meng Qinghua lei Department of Earth Sc.ences ETH ZürichZürich8092Switzerland Department of civil engineering and Industrial Design University of LiverpoolLiverpoolL693BXUK Department of civil Environmental and Natural Resources EngineeringLuleåUniversity of TechnologyLuleå97187Sweden Department of Earth Sc.ences Uppsala UniversityUppsala75105Sweden

In this study,we present a novel nodal integration-based particle finite element method(N-PFEM)designed for the dynamic analysis of saturated *** approach incorporates the nodal integration technique into a generalised Hellinger-Reissner(HR)variational principle,creating an implicit PFEM *** mitigate the volumetric locking issue in low-order elements,we employ a node-based strain smoothing *** discretising field variables at the centre of smoothing cells,we achieve nodal integration over cells,eliminating the need for sophisticated mapping operations after re-meshing in the *** express the discretised governing equations as a min-max optimisation problem,which is further reformulated as a standard second-order cone programming(SOcP)***,pore water pressure,and displacements are simultaneously determined using the advanced primal-dual interior point ***,our numerical model offers improved accuracy for stresses and pore water pressure compared to the displacement-based PFEM *** experiments demonstrate that the N-PFEM effic.ently captures both transient and long-term hydro-mechanical behaviour of saturated soils with high accuracy,obviating the need for stabilisation or regularisation techniques commonly employed in other nodal integration-based PFEM *** work holds significant implications for the development of robust and accurate numerical tools for studying saturated soil dynamics.

关键词： Particle finite element method Nodal integration Dynamic saturated media Second-order cone programming(SOcP)