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Efectiveness and petroleum geological signifcance of tectonic fractures in the ultra‑deep zone of the Kuqa foreland thrust belt:a case study of the Cretaceous Bashijiqike Formation in the Keshen gas feld

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Petroleum Science 2021年第3期18卷 728-741页

作者： Rong-Hu Zhang Ke Wang Qing-Lu Zeng chao-feng yu Jun-Peng Wang PetroChina Research Institute of Petroleum Exploration and Development Beijing 100086China PetroChina Hangzhou Research Institute of Geology Hangzhou 310023ZhejiangChina

The buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 *** average matrix porosity of the reservoir is 5.5%,and the average matrix permeability is 0.128×10^(−3)μm^(2).In order to reveal the characteristics and efectiveness of ultra-deep fractures and their efects on reservoir properties and natural gas production,outcrops,cores,thin section,image logs and production testing data are used to investigate the efectiveness of tectonic fractures in ultra-deep reservoirs in the Kuqa foreland thrust zone,and the corresponding geological signifcance for oil and gas exploration and development are *** fractures in the thrust belt include EW-trending high-angle tensile fractures and NS-trending vertical shear *** former has a relatively high flling rate,while the latter is mostly ***-fractures are usually grain-piercing-through cracks with width of 10-100 *** the planar view,the efective fractures are concentrated in the high part and wing zones of the long axis of the anticline,and along the vertical direction,they are mainly found in the tensile fracture zone above the neutral *** adjustment fracture zone has the strongest vertical extension abilities and high efectiveness,followed by the nearly EW longitudinal tensile fracture zone,and the netted fracture zone with multiple dip *** efectiveness of fracture is mainly controlled by fracture aperture and flling *** fractures can increase reservoir permeability by 1-2 orders of *** higher part of the anticline is associated with high tectonic fracture permeability,which control enrichment and high production of natural *** netted vertical open fractures efectively communicate with pores and throats of the reservoir matrix,which forms an apparent-homogenous to medium-heterogeneous body that is seen with high production of natural gas sustained for a long term.

关键词： Fracture efectiveness Ultra-deep Reservoir Foreland thrust belt Kuqa depression Geological signifcance

Optimized parameters of downhole all-metal PDM based on genetic algorithm

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Petroleum Science 2024年第4期21卷 2663-2676页

作者： Jia-Xing Lu Ling-Rong Kong yu Wang chao feng yu-Lin Gao China University of Geosciences (Beijing) Key Laboratory on Deep Geo-Drilling Technology of Ministry of Natural Resources

Currently, deep drilling operates under extreme conditions of high temperature and high pressure,demanding more from subterranean power motors. The all-metal positive displacement motor, known for its robust performance, is a critical choice for such drilling. The dimensions of the PDM are crucial for its performance output. To enhance this, optimization of the motor's profile using a genetic algorithm has been undertaken. The design process begins with the computation of the initial stator and rotor curves based on the equations for a screw cycloid. These curves are then refined using the least squares method for a precise fit. Following this, the PDM's mathematical model is optimized, and motor friction is assessed. The genetic algorithm process involves encoding variations and managing crossovers to optimize objective functions, including the isometric radius coefficient, eccentricity distance parameter,overflow area, and maximum slip speed. This optimization yields the ideal profile parameters that enhance the motor's output. Comparative analyses of the initial and optimized output characteristics were conducted, focusing on the effects of the isometric radius coefficient and overflow area on the motor's performance. Results indicate that the optimized motor's overflow area increased by 6.9%, while its rotational speed reduced by 6.58%. The torque, as tested by Infocus, saw substantial improvements of38.8%. This optimization provides a theoretical foundation for improving the output characteristics of allmetal PDMs and supports the ongoing development and research of PDM technology.

关键词： Positive displacement motor Genetic algorithm Profile optimization Matlab programming Overflow area

Highly reversible Zn anode enabled by anticatalytic carbon layer with suppressed hydrogen evolution

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Rare Metals 2024年第7期43卷 3044-3054页

作者： Wen-Duo Zhang Chuang Sun yu-Xuan Zhu feng Gao chao Lai School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhou221116China

Aqueous zinc-ion batteries(AZIBs)have emerged as a promising high-efficiency energy storage system due to the high energy density,low-cost and environmental ***,the practical application of AZIBs is severely restricted by the challenges faced by the Zn anode,which include uncontrollable dendrite growth,corrosion and hydrogen evolution ***,a simple and convenient physical vapor deposition(PVD)method is reported for fabricating uniform graphite as a protection layer on the surface of Zn *** high conductivity graphite layer on Zn anode(denoted as Zn@C)not only benefits the uniform distribution of the electric field,but also provides numerous Zn nucleation sites to regulate and navigate Zn-ion stripping/plating ***,the graphite layer with a poor catalytic activity endows the Zn@C anode with a highly suppressed hydrogen ***,a hydrogen and dendrite free anode is achieved with artificial anticatalytic carbon layer on Zn anode,exhibiting a high reversibility and excellent cycling stability over 2600 h at the current density of 5 mA·cm^(-2)with a capacity of 2.5 mAh·cm^(-2)and longtime cycling stability for assembled full *** work strategically designs the properties of the artificial interface layer to effectively address various challenges simultaneously,which presents insights for the future development of high-performance rechargeable AZIBs.

关键词： Zn metal anode Artificial anticatalytic layer Hydrogen suppression Dendrite free

The Complete Classification of Graphs whose Second Largest Eigenvalue of the Eccentricity Matrix is Less Than 1

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1741-1766页

作者： Jian feng WANG Xing yu LEI Shu chao LI Zoran STANIC School of Mathematics and Statistics Shandong University of TechnologyZibo255049P.R.China Faculty of Mathematics and Statistics Central China Normal UniversityWuhan430079P.R.China Faculty of Mathematics University of BelgradeStudentski trg 1611000BelgradeSerbia

The eccentricity matrix of a graph is obtained from the distance matrix by keeping the entries that are largest in their row or column,and replacing the remaining entries by *** matrix can be interpreted as an opposite to the adjacency matrix,which is on the contrary obtained from the distance matrix by keeping only the entries equal to *** the paper,we determine graphs having the second largest eigenvalue of eccentricity matrix less than 1.

关键词： Eccentricity matrix eigenvalue diameter principal submatrix forbidden subgraph

Supermassive black holes triggered by QCD axion bubbles

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Communications in Theoretical Physics 2024年第5期76卷 134-139页

作者： Hai-Jun Li Ying-Quan Peng Wei chao yu-feng Zhou Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

Spatial diversion and coordination of flood water for an urban flood control project in Suzhou, China

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Water Science and Engineering 2024年第2期17卷 108-117页

作者： yu Xu You-peng Xu Qiang Wang yue-feng Wang chao Gao Department of Geography and Spatial Information Techniques Ningbo UniversityNingbo 315211China State Key Laboratoryof Hydology Water Resources and Hydraulic Enginering Nanjing Hydraulic Research InstitueNanjing 210029China Laboratory of Sustainable Urban Drainage Ningbo UniversityNingbo 31521lChina Schol of Gegraphical and Oceanographic Sciences Nanjing UniversiyNanjing 210023China School of Geography and Tourism Chongqing Normal UniversityChongqing 401331China

Suzhou City,located in the Yangtze River Delta in China,is prone to flooding due to a complex combination of natural factors,including its monsoon climate,low elevation,and tidally influenced position,as well as intensive human *** Large Encirclement Flood Control Project(LEFCP)was launched to cope with serious floods in the urban *** project changed the spatiotemporal pattern of flood processes and caused spatial diversion of floods from the urban area to the outskirts of the ***,this study developed a distributed flood simulation model in order to understand this transition of flood *** results revealed that the LEFCP effectively protected the urban areas from floods,but the present scheduling schemes resulted in the spatial diversion of floods to the outskirts of the *** rainstorm frequencies of 10.0%to 0.5%,the water level differences between two representative water level stations(Miduqiao(MDQ)and fengqiao(FQ))located inside and outside the LEFCP area,ranged from 0.75 m to 0.24 m and from 1.80 m to 1.58 m,*** addition,the flood safety margin at MDQ and the duration with the water level exceeding the warning water level at FQ ranged from 0.95 m to 0.43 m and from 4 h to 22 h,*** scheduling schemes for the hydraulic facilities of the LEFCP in extreme precipitation cases were developed ac-cording to food simulations under seven scheduling *** helps to regulate the spatial flood diversion caused by the LEFCP during extreme precipitation.

关键词： Urban flooding Urban flood control project Rainstorm fregue ncy Flood simulation model Suzhou City

Quasi-in-situ Observation and SKPFM Studies on Phosphate Protective Film and Surface Micro-Galvanic Corrosion in Biological Mg-3Zn-xNd Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 648-664页

作者： Zhaochen yu Kaixuan feng Shuyun Deng Yang Chen Hong Yan Honggun Song chao Luo Zhi Hu School of Advanced Manufacturing Nanchang UniversityNanchang330031China Institute for Advanced Study Nanchang UniversityNanchang330031China

The phosphate protective film and micro-galvanic corrosion of biological Mg-3Zn-xNd (x = 0, 0.6, 1.2) alloys were investigated by scanning and transmission electron microscopy, quasi-in-situ observation, scanning Kelvin probe force microscopy (SKPFM) and electrochemical tests. The results revealed the Mg-Zn-Nd phases formed in Mg-3Zn alloy contained with Nd. Adding Nd resulted in a significant decline in the cracks of the phosphate protective film and micro-galvanic corrosion of alloys, which were recorded by quasi-in-situ observation. In addition, the Volta potential difference of Mg-Zn-Nd/α-Mg (~ 188 mV) was lower than MgZn/α-Mg (~ 419 mV) and Zn-rich/α-Mg (~ 260 mV), and the corrosion rates of alloys markedly decreased after the addition of 0.6 wt% Nd. The improvement in corrosion resistance of Nd-containing alloys was mainly attributed to the following: (i) the addition of Nd reduced the Volta potential difference (second phases/α-Mg);(ii) the phosphate protective film containing Nd_(2)O_(3) deposited on the surface of the alloys, effectively preventing the penetration of harmful anions.

关键词： Magnesium alloys Quasi-in-situ observation Phosphate protective film Scanning Kelvin probe force microscopy(SKPFM) Micro-galvanic corrosion

Sensing properties and mechanisms of LaF_(3)-Co_(3)O_(4) nanorods for low-concentration methanol detection

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Rare Metals 2024年第5期43卷 2193-2204页

作者： Xiao-Xi He Hong-feng Chai Yi-Wen Zhou Ke-Wei Liu Ze-Xin yu chao Zhang College of Mechanical Engineering Yangzhou UniversityYangzhou225127China Institutefor Manufacturing Technologies of Ceramic Components and Composites(IMTCCC) University of Stuttgart70569 StuttgartGermany

Methanol is one of the characteristic gases that distinguish between healthy individuals and lung cancer(LC)lesions in exhaled human *** concentration in exhaled breath is generally below one part per million(1×10^(-6)).The second-phase composite is widely regarded as one of the methods to improve the gas-sensing perfor-mance of metal oxide semiconductor(MOS)*** this study,LaF_(3)-Co_(3)O_(4) was synthesized by a simple hydrothermal method to enhance its low-concentration methanol gas-sensing performance.5 at%LaF_(3)-Co_(3)O_(4) nanorods exhibited excellent methanol detection performance,including a wider linear detection concentration range(0.2×10^(-6)~5×10^(-6)),a response value exceeding 4.0 for 1×10^(-6)methanol at 275°C and 75%relative humidity(RH),long-term stability(maximum deviation within 15%over 2 weeks),and excellent *** mechanism of performance enhancement was studied using various techniques,and density functional *** special spinel structure of Co_(3)O_(4),the high ionic migration of F-in LaF_(3),the larger specific surface area of 5 at%LaF_(3)-Co_(3)O_(4) nanorods,and the generated crystal defects all explain the excellentmethanol gas-sensing *** work provides a novel route to prepare MOS composite materials for low-concentration methanol gas detection.

关键词： Gas sensor LaF_(3) Co_(3)O_(4) Methanol Lung cancer

High-Order DG Schemes with Subcell Limiting Strategies for Simulations of Shocks,Vortices and Sound Waves in Materials Science Problems

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Fluid Dynamics & Materials Processing 2024年第10期20卷 2183-2204页

作者： Zhenhua Jiang Xi Deng Xin Zhang chao Yan feng Xiao Jian yu College of Aeronautics Science and Engineering Beijing University of Aeronautics and AstronauticsBeijing100191China Department of Chemical Engineering Imperial College LondonLondonSW72AZUK Department of Engineering University of CambridgeCambridgeCB21PZUK Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo152-8550Japan

Shock waves,characterized by abrupt changes in pressure,temperature,and density,play a significant role in various materials science processes involving *** high-energy phenomena are utilized across multiple fields and applications to achieve unique material properties and facilitate advanced manufacturing *** simulations of these phenomena require numerical schemes that can represent shock waves without spurious oscillations and simultaneously capture acoustic waves for a wide range of wavelength *** work suggests a high-order discontinuous Galerkin(DG)method with a finite volume(FV)subcell limiting strategies to achieve better subcell resolution and lower numerical diffusion *** switching to the FV discretization on an embedded sub-cell grid,the method displays advantages with respect to both DG accuracy and FV shock-capturing *** FV scheme utilizes a class of high-fidelity schemes that are built upon the boundary variation diminishing(BVD)reconstruction *** method is therefore able to resolve discontinuities and multi-scale structures on the subcell level,while preserving the favorable properties of the high-order DG *** have tested the present DG method up to the 6th-order accuracy for both smooth and discontinuous noise problems.

关键词： Discontinuous Galerkin finite volume subcell limiting shock associated noise computational aeroacoustics