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Dynamic characteristics of the pipeline inspection gauge under girth weld excitation in submarine pipeline

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Petroleum Science 2022年第2期19卷 774-788页

作者： Hang Zhang meng-qi gao Biao Tang Can Cui Xue-Feng Xu College of Mechanical and Storage and Transportation Engineering China University of Petroleum-BeijingBeijing102249China CNPC offshore Engineering Co.Ltd Beijing102200China

Pipeline inner inspection technology based on Pipeline Inspection Gauge(PIG),is the primary means for ensuring the safety of submarine *** dynamic characteristics of a PIG can change abruptly with the excitation of obstacles such as girth welds inside the pipeline,which would result in failure or inaccuracy of the inspection *** study establishes a dynamic model of the PIG sealing disc based on Kelvin spring damping in the circumferentially confined *** axial vibration differential equations of the PIG is examined in ***/ADAMS is used to conduct the dynamic simulation of the PIG at different motion velocities and center of mass positions while passing through the girth weld *** indicate that the axial vibration caused by the girth weld intensifies substantially as the speed of the PIG increases,while the pitch and vertical vibrations exhibit a significant decline with an increase in the motion *** change in the PIG’s center of mass positions has little effect on its axial vibration,while the pitch and vertical vibration conditions are significantly different in the same circumstances.

关键词： Pipeline inspection gauge Multi-system model Dynamic response Shock vibration Girth weld Submarine pipeline

Metal phosphonate-derived cobalt/nickel phosphide@N-doped carbon hybrids as efficient bifunctional oxygen electrodes for Zn-air batteries

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Frontiers of Chemical Science and Engineering 2022年第9期16卷 1367-1376页

作者： Cai-Yue Wang meng-qi gao Cheng-Cai Zhao Li-Min Zhao Hui Zhao School of Materials Science and Engineering Liaocheng UniversityLiaocheng 252000China

The exploration of efficient bifunctional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction is pivotal for the development of rechargeable metal–air *** metal phosphides are emerging as promising catalyst candidates because of their superb activity and low ***,a novel metal phosphonate-derived cobalt/nickel phosphide@N-doped carbon hybrid was developed by a carbothermal reduction of cobalt/nickel phosphonate hybrids with different Co/Ni molar *** metal phosphonate derivation method achieved an intimately coupled interaction between metal phosphides and a heteroatom-doped carbon *** resultant Co_(2)P/Ni_(3)P@NC-0.2 enables an impressive electrocatalytic oxygen reduction reaction activity,comparable with those of state-of-the-art Pt/C catalysts in terms of onset potential(0.88 V),4e‒selectivity,methanol tolerance,and long-term ***,remarkable oxygen evolution reaction activity was also observed in alkaline *** high activity is ascribed to the N-doping,abundant accessible catalytic active sites,and the synergistic effect among the *** work not only describes a highefficiency electrocatalyst for both oxygen reduction reaction and oxygen evolution reaction,but also highlights the application of metal phosphonate hybrids in fabricating metal phosphides with tunable structures,which is of great significance in the energy conversion field.

关键词： metal phosphonate cobalt/nickel phosphide N-doped carbon oxygen electrochemistry Zn−air battery

Bionic immunoactivator copresenting autophagy promoting and costimulatory molecules for synergistic cancer immunotherapy

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Nano Research 2024年第3期17卷 1710-1724页

作者： Yiwei Peng Yiliang Yang Zhenzhen Yang Datong gao Jiajia Li qi Sun Yitian Du meng Lin Xianrong qi Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery System School of Pharmaceutical SciencesPeking UniversityBeijing 100191China

Immunotherapy has great promise in improving malignant tumor ***,the efficacy of existing strategies is often limited by the immunosuppressive ***,we demonstrate an in situ bionic immunoactivator,PLT-Bec1/DTA-1,with possessed natural advantages of platelets for tumor recruitment and activation,on which DTA-1(CD357 monoclonal antibody)and Bec1 were tethered as combined immune ***-Bec1/DTA-1,as a self-triggered release repository,can deliver the pre-tethered Bec1 and DTA-1 deeply through the secretion of platelet microparticles(PMPs),thereby cooperate tacitly and exhibit superiority in immune activation of dendritic cells(DCs)and T cells via autophagy inducibility,coupled with glucocorticoid-induced tumor necrosis factor receptor(GITR)-triggered T_(Reg) suppression,remodeled the immunosuppressive network of tumor ***-Bec1/DTA-1 promoted antigen presentation and T cell proliferation,and alleviated the low activity state of bone marrow-derived dendritic cells(BMDCs)in tumor suppressive ***-Bec1/DTA-1 inhibited tumor recurrence(5-and 13-fold lower of control group in tumor volume)and CD8^(+)T/T_(Reg) ratio(6.3-and 8.8-fold *** group)in mouse tumor model after intravenous or subcutaneous ***,PLT-Bec1/DTA-1 prevented tumor colonization in lung through in situ immune activation,and was slightly superior to the combined of Bec1 and *** findings highlight the promise of delivering immunostimulatory payloads via bionic carriers,eliciting automatic in situ activation of effector immune cells in tumor microenvironment for tumor *** these results provide promising prospects into the application of immunoactivator in improving cancer synergistic immunotherapy to overcome the bottlenecks in clinic.

关键词： in situ bionic immunoactivator autophagy glucocorticoid-induced tumor necrosis factor receptor(GITR)agonist platelets and platelet microparticles cancer immunotherapy

Constructing robust NiFe LDHs-NiFe alloy gradient hybrid bifunctional catalyst for overall water splitting:one-step electrodeposition and surface reconstruction

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Rare Metals 2023年第7期42卷 2272-2283页

作者： Yi-Fei Chen Jia-Hong Li Tian-Tian Liu Si-Hang You Peng Liu Fu-Jin Li meng-qi gao Shu-Guang Chen Fei-Fei Zhang School of Materials Science and Engineering Changsha University of Science and TechnologyChangsha410114China Faculty of Engineering Department of Materials Science and EngineeringNational University of SingaporeSingapore117576Singapore School of Materials Science and Engineering Jilin UniversityChangchun130022China

NiFe layered double hydroxides(NiFe LDHs)have been intensively developed for the oxygen evolution reaction(OER)in alkaline media;however,their unsatisfactory hydrogen evolution reaction(HER)performance limits their practical application in overall water ***,a simple and efficient one-step electrodeposition method is used to accomplish in situ growth of NiFe LDHsNiFe alloy gradient hybrid coatings on a carbon cloth(CC).Within the binder-free electrode,NiFe LDHs nanosheets with a low-crystalline nature exhibit highly active bifunctional OER/HER activities,and the NiFe alloy acts as a stable electron highway and strong skeleton bridge between NiFe LDHs and the *** the electrodes are simultaneously employed as the cathode and anode for overall water splitting,they require low cell potentials of 1.441 V at10 mA·cm^(-2)and 1.703 V at 100 mA·cm^(-2),respectively,and they demonstrate outstanding stability at a current density greater than 100 mA·cm^(-2)for more than 100 *** is one of the best bifunctional OER and HER catalysts for overall water *** lattice defects and surface reconstructions crucially contribute to the bifunctional OER/HER activities of NiFe *** simple and scalable synthesis approach presents an intriguing paradigm for industrial production,and the fabricated electrode has potential application in high-current-density water splitting.

关键词： Bifunctional Electrodeposition Gradient hybrid NiFe layered double hydroxides(NiFe LDHs) Overall water splitting

Formation mechanism of fault accommodation zones under combined stress in graben basin:Implications from geomechanical modeling

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Petroleum Science 2024年第1期21卷 54-76页

作者： qi-qiang Ren Jin-Liang gao Rong-Tao Jiang Jin Wang meng-Ping Li Jian-Wei Feng Institute of Sedimentary Geology Chengdu University of TechnologyChengdu 610059SichuanChina PetroChina Research Institute of Petroleum Exploration and Development Beijing100083China Jianghan Oilfield Oil and Gas Production Capacity Construction Management Center Chongqing408000China Sinopec Chongqing Fuling Shale Gas Exploration and Development Company Chongqing408000China College of Energy Chengdu University of TechnologyChengdu 610059SichuanChina School of Geoscience China University of Petroleum(East China)Qingdao 266580ShandongChina

A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults *** numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation *** study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical *** three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation *** with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben *** the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were *** by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale *** the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly *** junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation *** the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were

关键词： Fault accommodation zone Graben basin Fault activity Tectonic physical simulation experiment Finite element numerical simulation Dongxin fault zone

Influence of the Acoustic Liner in Large Eddy Simulation of Longitudinal Thermoacoustic Instability in a Model Annular Combustor

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Journal of Thermal Science 2024年第2期33卷 710-724页

作者： meng Sheng ZHANG Man gao Yi AECC Commercial Aircraft Engine Co. Ltd.Shanghai200241China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai200240China

Although extensive efforts have been made to dampen the thermoacoustic instability,successfully controlling the pressure oscillations in modern gas turbines or aeroengines remains *** influence of the acoustic liner on the longitudinal thermoacoustic mode in a model annular combustor is investigated by Large Eddy Simulation(LES) in this *** result of the self-excited longitudinal thermoacoustic instability without the liner agrees well with the frequency and acoustic analysis of the pressure mode based on experimental *** different bias flow velocities of the liner located downstream of the combustor are then *** results reveal that the existence of the liner influences not only the acoustic field but also the flow *** the bias velocity is large,it leads to intense turbulence-induced fluctuations,and the pressure oscillation is modulated *** shows that the weak coupling between flow and pressure oscillations plays a significant role in the onset of the intermittency of a thermoacoustic *** on the dynamic analysis of the thermoacoustic system with the acoustic liner,this intermittency is caused by the influence of the flow field on the flame-acoustic ***,a low-order modeling method based on Van der Pol(VdP) oscillator with additive stochastic forcing is conducted to reproduce the evolving dynamics of the thermoacoustic *** the numerical cases demonstrated in this work are relatively simpler than those in a practical combustion system,the results are helpful for us to understand the effect of the acoustic liner and show the attractive potential to apply this device to suppress thermoacoustic instability.

关键词： thermoacoustic instability acoustic liner Large Eddy Simulation low-order modeling

Incidence Coloring of Outer-1-planar Graphs

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 840-848页

作者： meng-ke qi Xin ZHANG School of Mathematics and Statistics Xidian UniversityXi'an 710071China

A graph is outer-1-planar if it can be drawn in the plane so that all vertices lie on the outer-face and each edge crosses at most one another *** is known that every outer-1-planar graph is a planar *** this paper,we conjecture that every planar graph G has a proper incidence(Δ(G)+2)-coloring and confirm it for outer-1-planar graphs with maximum degree at least 8 or with girth at least ***,we prove that every outer-1-planar graph G has an incidence(Δ(G)+3,2)-coloring,and every outer-1-planar graph G with maximum degree at least 8 or with girth at least 4 has an incidence(Δ(G)+2,2)-coloring.

关键词： incidence coloring outer--planar graph planar graph

Deciphering and integrating invariants for neural operator learning with various physical mechanisms

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National Science Review 2024年第4期11卷 111-122页

作者： Rui Zhang qi meng Zhi-Ming Ma Academy of Mathematics and Systems Science Chinese Academy of Sciences(CAS) Microsoft Research

Neural operators have been explored as surrogate models for simulating physical systems to overcome the limitations of traditional partial differential equation(PDE) solvers. However, most existing operator learning methods assume that the data originate from a single physical mechanism, limiting their applicability and performance in more realistic scenarios. To this end, we propose the physical invariant attention neural operator(PIANO) to decipher and integrate the physical invariants for operator learning from the PDE series with various physical mechanisms. PIANO employs self-supervised learning to extract physical knowledge and attention mechanisms to integrate them into dynamic convolutional *** to existing techniques, PIANO can reduce the relative error by 13.6%–82.2% on PDE forecasting tasks across varying coefficients, forces or boundary conditions. Additionally, varied downstream tasks reveal that the PI embeddings deciphered by PIANO align well with the underlying invariants in the PDE systems, verifying the physical significance of PIANO.

关键词： neural operator PDE solver contrastive learning physical invariants

Iterative Signal Detection Based Soft Interference Cancellation for Satellite-Terrestrial Downlink NOMA Systems

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China Communications 2024年第8期21卷 249-263页

作者： Sun meng Zhang qi Yao Haipeng gao Ran Xin Xiangjun Tian Feng Feng Weiying Chen Dong School of Electronic Engineering Beijing University of Posts and Telecommunications(BUPT)Beijing 100876China Beijing Key Laboratory of Space-Ground Interconnection and Convergence State Key Laboratory of Information Photonics and Optical CommunicationsSchool of Electronic EngineeringBeijing University of Posts and Telecommunications(BUPT)Beijing 100876China School of Information and Communication Engineering Beijing University of Posts and Telecommunications(BUPT)Beijing 100876China Beijing Institute of Technology Beijing 100081China Beihang University Beijing 100191China China Academy of Space Technology(CAST) Beijing 100094China

To improve the bit error rate(BER)performance of multi-user signal detection in satelliteterrestrial downlink non-orthogonal multiple access(NOMA)systems,an iterative signal detection algorithm based on soft interference cancellation with optimal power allocation is *** that power allocation has a significant impact on BER performance,the optimal power allocation is obtained by minimizing the average BER of NOMA *** to the allocated powers,successive interference cancellation(SIC)between NOMA users is performed in descending power *** each user,an iterative soft interference cancellation is performed,and soft symbol probabilities are calculated for soft *** improve detection accuracy and without increasing the complexity,the aforementioned algorithm is optimized by adding minimum mean square error(MMSE)signal estimation before detection,and in each iteration soft symbol probabilities are utilized for soft-decision of the current user and also for the update of soft interference of the previous *** results illustrate that the optimized algorithm ***-IDBSIC significantly outperforms joint multi-user detection and SIC detection by 7.57dB and 8.03dB in terms of BER performance.

关键词： non-orthogonal multiple access(NOMA) resource allocation satellite-terrestrial communication signal detection soft interference cancellation