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Experimental study of the relationship between fluid density and saturation and sonic wave velocity of rock samples from the WXS Depression,South China Sea

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Petroleum Science 2011年第1期8卷 43-48页

作者： Pei Fagen Zou Changchun He Tao Pan Lingzhi Xiao Kun Shi Ge Ren Keying Key Laboratory of Geo-detection（China University of Geosciences Beijing）Ministry of EducationBeijing 100083 China School of Earth and space Sciences Peking UniversityBeijing 100871China Zhanjiang Branch of China National Offshore Oil Corporation ltd. Guangdong 524057China

The relationship between fluid density and saturation and sonic wave velocity of rock samples taken from the WXS Depression in the South China Sea was studied by an oil-water replacement experiment under simulated in-situ temperature and pressure *** kinds of low-density oils（0.691 and 0.749 g/cm^3） and two kinds of high-density oils（0.834 and 0.873 g/cm^3） were used to saturate the rock samples at different oil-saturation states,and the saturated P- and S-wave velocities were *** Gassmann＇s equation,the theoretical P- and S-wave velocities were also calculated by the fluid replacement *** the comparison of the measured values and the theoretical values, this study comes to the following conclusions.（1） With the increase of oil saturation and the decrease of water saturation,the P-wave velocity of rock samples saturated by low-density oil increases and the changing rule is in accord with the effective fluid theory;the P-wave velocity of rock samples saturated by high-density oil decreases and the changing rule goes against the theory.（2） With the increase of oil density（namely 0.691→0.749→0.834→0.873 g/cm^3） when oil saturation is unchanged,P-wave velocity increases gradually.（3） The S-wave velocity is always stable and is not affected by the change of oil density and *** results can be used to constrain pre-stack seismic inversion,and the variation rule of sonic wave velocity is valuable for hydrocarbon identification in the study area.

关键词： Rock physics saturation compressional wave shear wave water drive Gassmann's equation fluid replacement

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Study on the pipe friction resistance in long-distance rock pipe jacking engineering

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Underground space 2023年第2期9卷 173-185页

作者： Peng Chen Xinrong Liu Zhiyun Deng Ninghui Liang Libing Du Han Du Yedi Huang Lingyun Deng Gaoyang Yang School of Civil Engineering Chongqing UniversityChongqing 400045China Chongqing Municipal Design and Research Institute Co. Ltd.Chongqing 404100China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China Powerchina Chengdu Engineering Co. Ltd.ChengduSichuan 610072China Wuhan Branch of China Construction Steel Structure Co. Ltd.WuhanHubei 430000China

Previous studies on pipe friction resistance are mainly concentrated in the soil layer,whereas the study on that in the rock stratum is *** estimate the pipe friction resistance in the rock stratum,the calculation models of pipe friction resistance and their applica-tion conditions were compared *** the friction resistance calculation model for pipe jacking in the rock stratum was established and ***,the measured(FM)and the computed(FN)pipe friction resistance was compared to validate the simplified friction resistance calculation *** following conclusions can be drawn:(1)The existing calculation methods of pipe friction resistance can be well verified in the soil layer but cannot be applied in the rock stratum.(2)Sediment,pipe–rock friction coefficient and mud buoyancy are the main factors affecting the pipe friction resistance in long-distance rock pipe jacking engineering.(3)The simplified calculation model established by Deng et *** estimate the pipe friction resistance in different rock strata at different jacking stages with satisfac-tory *** research on the pipe-rock friction coefficient in different rock strata with different pipe–rock contact conditions merits further investigation to better predict the pipe friction resistance in the rock *** research results have certain practica-bility and can provide a reference for similar projects.

关键词： Pipe jacking Calculation model Friction resistance Pipe-rock contact state Rock stratum

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Inter-satellite link augmented BeiDou-3 orbit determination for precise point positioning

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Chinese Journal of aeronautics 2022年第4期35卷 332-343页

作者： Liqian ZHAO Xiaogong HU Chengpan TANG Shanshi ZHOU Yueling CAO Qianxin WANG Ranran SU space Star Technology Co. Ltd.Beijing 100095China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221116China Beijing Satellite Navigation Center Beijing 100094China

Precise Point Positioning(PPP) requires precise products, including high-accuracy satellite orbit and clock parameters. It is impossible to obtain an orbit solution that is sufficiently accurate for PPP services with a regional tracking network;therefore, satellite orbits are usually estimated by a global tracking network with a large number of ground stations. However, it is expensive to build globally distributed stations. Fortunately, BeiDou-3 satellites carry an InterSatellite Link(ISL) payload, which can track the whole arc of the BeiDou-3 satellites and enhance the orbit determination accuracy with regional ground stations. In this contribution, a novel orbit determination strategy for BeiDou-3 PPP is proposed, in which the BeiDou-3 satellite orbits are enhanced by the ISL. First, the generation of precise satellite products is demonstrated in *** addition, the products are assessed by Satellite Laser Ranging(SLR) residuals and overlap comparisons. Moreover, the products are used for receivers in China's Mainland to carry out the static and kinematic modes to research the PPP performance of Bei Dou-3’s 3IGSO/24MEO *** SLR validations of the satellite orbits demonstrate an accuracy better than 0.1 m in the radial component, and the orbit overlap comparisons show accuracies of 0.016 m in the radial component,0.088 m in the along-track component and 0.087 m in the cross-track component. The Standard Deviation(STD) in the differences in overlapping arcs for the estimated satellite clocks is approximately 0.10 ns. The static PPP results demonstrate that the error in both the horizontal and vertical components is smaller than 10 cm after 30 minutes of convergence. After 24 hours of convergence,the errors are 0.70 cm, 0.63 cm and 1.99 cm for the north, east and up components, *** kinematic PPP experiment illustrates that the Root Mean Square(RMS) position errors in the north, east and up components are approximately 3.23 cm, 5.27 cm a

关键词： BeiDou-3 Clock offsets Convergence Inter-satellite link Precise Point Positioning Regional ground stations Satellite orbits

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Automatic and Rapid Throughflow-Based Optimal Design Method for Multi-Stage Axial-Flow Compressors

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Journal of Thermal Science 2025年第1期 77-91页

作者： LEI Fan ZHANG Xiawen JU Yaping ZHANG Chuhua Department of Fluid Machinery and Engineering School of Energy and Power EngineeringXi'an Jiaotong University Production and Environmental Department China Huaneng Group.Co.Ltd. State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University

Throughflow design has the advantages of less time consumption and large optimization space,and thus is the corner stone of advanced design system of multi-stage axial-flow *** majority of relevant studies were limited to the throughflow inverse designs,and quite few works have been till now devoted to the throughflow optimal *** this work,an automatic and rapid throughflow-based optimal design method is proposed for axial-flow compressors in which a throughflow inverse design solver is embedded in optimal genetic algorithm to improve the design efficiency of axial-flow *** types of design parameters in the throughflow inverse design of axial-flow compressors,i.e.,swirl and shroud curve,are simultaneously used to optimize both the blade shape and flow *** proposed method is validated by the redesign optimization of the benchmark axial-flow compressor NASA Stage 35,and the CFD predictions show that the throughflow-based optimization leads to 1.18% efficiency benefit at design *** proposed method is then utilized to the two-dimensional throughflow optimal design of a large-scale 6.5-stage axial-flow industrial *** optimal design results are confirmed by CFD predictions,indicating that the proposed method can effectively improve the design adiabatic efficiency of the compressors by 1.09% within a few minutes on desk-top *** throughflow design implications are also obtained for advanced axial-flow industrial *** work could enhance the capability of throughflow design method and has engineering application value to explore the throughflow optimization space of multi-stage axial-flow compressors.

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Microfossils and molecular records in oil shales of the Songliao Basin and implications for paleo-depositional environment

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Science China Earth Sciences 2009年第10期52卷 1559-1571页

作者： FENG ZiHui FANG Wei WANG Xue HUANG ChunYan HUO QiuLi ZHANG JuHe HUANG QingHua ZHANG Lei School of Earth and space Sciences Peking UniversityBeijing 1000871China Exploration and Development Research Institute PetroChina Daqing Oilfield Company Ltd.Daqing 163712China

Several oil shale beds, over 10 m thick, occur at the base of the first member of the Upper Cretaceous Qingshankou Formation (K2qn1) in the Songliao Basin. They act both as excellent source rocks for conventional oil and as potential oil deposit for shale oil production. Here we combine micropaleon-tology with organic geochemistry to investigate the paleo-depositional environment and organic source characteristics of the oil shales and black shales. Our results indicate that algal remains are dominant microfossils in K2qn1 oil shales, and their relatively high abundance suggests a major algal thriving event during the oil shale deposition. The presence of fresh water and brackish water species, Sentusidinium, Vesperopsis and Nyktericysta, and marine or brackish water deltaic and lagoonal species such as Kiokansium and Dinogymniopsis demonstrate that this paleo-continental lake was influenced by marine transgressions at the time of K2qn1 oil shale formation. The extremely low pristine/phytane ratios, relatively high abundance of gammacerane and 4-methyl steranes, and low δ 13C values of C14-C37 n-alkanes in the oil shale organic extracts indicate the deposition of oil shales in anoxic and highly stratified water columns and the significant contribution of lacustrine algae to sedimentary organic matter. High molecular-weight paraffinic hydrocarbons with unusually high abundance of nC43, nC45, and nC47 may be related to special algal species associated with marine transgression events. The giant water body of Songliao paleo-lake and the change in the organic and chemical environment (such as nutrition source and water column salinity) associated with seawater transgression into the lake are among the most important reasons for oil shales in the Songliao Basin being different from mudstone and oil shale in other rifted basins.

关键词： Songliao Basin oil shale micro-fossil molecular fossil alga thrive event

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Pore Structure Characterization of Clay Minerals in the Lower Karamay Formation Conglomerate Reservoir in the Junggar Basin and its Impact on Hydrocarbon Storage and Seepage

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Acta Geologica Sinica(English Edition) 2021年第2期95卷 558-569页

作者： Taskyn ABITKAZY DU Shuheng XU Feng SHI Yongmin School of Earth and space Sciences Peking UniversityBeijing 100871China Research Institute of Petroleum Exploration and Development Co. Ltd.CNPCBeijing 100083China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

The micro-nano pore structure of conglomerate in the Lower Karamay Formation of the Xinjiang Oilfield,Junggar Basin,northern China is characterized to predict its impact on fluid reserves and *** clay minerals are mainly kaolinite(67%),followed by an illite/smectite mixed layer(18%),illite(10%),and chlorite(5%).For kaolinite,pore throats between 0–200 nm are dominant,accounting for 90%of the total pore *** illite/smectite mixed layer,pore throats also between 0–200 nm account for nearly 80%,while pore throats between 200-500 nm only account for 15%.For illite,pore throats below 100 nm account for about 80%,while pore throats in the range of 100–500 nm only account for 20%.For chlorite,most throats are below 200 *** pore roundness of illite is the highest,while the pore roundness of chlorite is relatively *** lower limits of the dynamic and static pore throat radii are 42.128 nm and 72.42 nm,*** theoretical contribution rates of the illite/smectite mixed layer,kaolinite,illite and chlorite to storage/seepage are 60%/45.86%,52.72%/38.18%,37.07%/28.78%and 32.97%/26.3%,***,the contribution rates of clay minerals in the study area are as follows:illite/smectite mixed layer,kaolinite,illite and chlorite.

关键词： oil conglomerate clay minerals micro-nano pore reservoir characterization Triassic Xinjiang

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A regulated digital currency

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Science China(Information Sciences) 2019年第3期62卷 119-130页

作者： Yanbing WU Haining FAN Xiaoyun WANG Guangnan ZOU Institute for Advanced Study Tsinghua University Department of Computer Science and Technology Tsinghua University space Star Technology Co. Ltd

The decentralized digital currency Bitcoin is an anonymous alternative to the centralized banking system and enjoys widespread and increasing adoption. Since Bitcoin created, many other electronic currencies have been developed. We propose a protocol for an electronic currency for making anonymous payments that can be supervised by an auditor, who has sole access to the transaction history. Other electronic currencies provide only anonymity, which is convenient for making illegal transactions without regulation. For users, miners, and banks, the transactions of our electronic currency are anonymous, and only auditors can see how it is used. We make use of POW(prove-of-work) technique that allows for distributed decisionmaking within a network, namely the Bitcoin blockchain protocol. We combine the POW and blockchain technology of Bitcoin to give better protection against double-spending attacks.

关键词： Blockchain Bitcoin anonymous digital currency regulated proof-of-work

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Assembly Auxiliary System for Narrow Cabins of spacecraft

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 1080-1088页

作者： LIU Yi LI Shiqi WANG Junfeng School of Mechanical Science & Engineering Huazhong University of Science and Technology CSR Zhuzhou Electric Locomotive Co. Ltd.

Due to the narrow space and complex structure of spacecraft cabin, the existing asssembly systems can not well suit for the assembly process of cabin products. This paper aims to introduce an assembly auxiliary system for cabin products. A hierarchical-classification method is proposed to re-adjust the initial assembly relationship of cabin into a new hierarchical structure for efficient assembly planning. An improved ant colony algorithm based on three assembly principles is established for searching a optimizational assembly sequence of cabin parts. A mixed reality assembly environment is constructed with enhanced inforamtion to promote interaction efficiency of assembly training and guidance. Based on the machine vision technology, the inspection of left redundant objects and measurement of parts distance in inner cabin are efficiently performed. The proposed system has been applied to the assembly work of a spacecraft cabin with 107 parts, which includes cabin assembly planning, assembly training and assembly quality inspection. The application result indicates that the proposed system can be an effective assistant tool to cabin assembly works and provide an intuitive and real assembly experience for workers. This paper presents an assembly auxiliary system for spacecraft cabin products, which can provide technical support to the spacecraft cabin assembly industry.

关键词： assembly planning hierarchical-classification ant colony algorithm augmented reality visual inspection

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Pattern control for large-scale spacecraft swarms in elliptic orbits via density fields

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Chinese Journal of aeronautics 2022年第3期35卷 367-379页

作者： Chihang YANG Hao ZHANG Weida FU Key Laboratory of space Utilization Technology and Engineer Center for Space UtilizationChinese Academy of SciencesBeijing 100094China University of Chinese Academy of Sciences Beijing 100049China DFH Satellite Co. LtdBeijing 100094China

space swarms,enabled by the miniaturization of spacecraft,have the potential capability to lower costs,increase efficiencies,and broaden the horizons of space *** formation control problem of large-scale spacecraft swarms flying around an elliptic orbit is *** objective is to drive the entire formation to produce a specified spatial *** relative motion between agents becomes complicated as the number of agents ***,a density-based method is adopted,which concerns the density evolution of the entire swarm instead of the trajectories of *** density-based method manipulates the density evolution with Partial Differential Equations(PDEs).This density-based control in this work has two aspects,global pattern control of the whole swarm and local collision-avoidance between nearby *** global behavior of the swarm is driven via designing velocity *** each spacecraft,the Q-guidance steering law is adopted to track the desired velocity with accelerations in a distributed ***,the final stable velocity field is required to be zero in the classical density-based approach,which appears as an obstacle from the viewpoint of astrodynamics since the periodic relative motion is always *** solve this issue,a novel transformation is constructed based on the periodic solutions of Tschauner-Hempel(TH)*** relative motion in Cartesian coordinates is then transformed into a new coordinate system,which permits zero-velocity in a stable *** local behavior of the swarm,such as achieving collision avoidance,is achieved via a carefully-designed local density estimation *** simulations are provided to demonstrate the performance of this approach.

关键词： Collision avoidance Density-based feedback control Distributed control Formation flight Large-scale swarms Pattern generation PDE-based control TH equation

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TBM tunneling in extremely hard and abrasive rocks:Problems,solutions and assisting methods

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Journal of Central South University 2021年第2期28卷 454-480页

作者： ZHENG Yan-long HE Lei School of Civil Engineering Southeast UniversityNanjing 211189China Nanjing Institute of Underground space Technology Co. Ltd.Nanjing 211189China

Extremely hard and abrasive rocks pose great challenges to the past and ongoing TBM projects by increasing cutter wear and reducing penetration rates.A considerable amount of research has been conducted to improve the performance of TBMs in those challenging grounds by either improving the capacity of TBMs or developing assisting rock breakage *** paper first highlights the challenges of hard and abrasive rocks on TBM tunneling through case *** then presents the development of hard rock TBMs and reviews the technologies that can be used individually or as assistance to mechanical excavators to break hard *** are placed on technologies of high pressure waterjet,laser and *** state of the art of field and laboratory research,problems and research directions of those technologies are *** assisting methods are technically feasible;however,the main challenges of using those methods in the field are that the energy consumption can be over 10 times high and that the existing equipments have robustness *** research should be conducted to study the overall energy consumption using TBMs and the assisting *** waterjet,laser and microwave technologies should also be developed to make the assistance economically viable.

关键词： hard and abrasive rocks tunnel boring machine waterjet laser microwave

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