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S-wave velocity inversion and prediction using a deep hybrid neural network

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Science China Earth Sciences 2022年第4期65卷 724-741页

作者： Jun WANG Junxing CAO Shuang Zhao Qiaomu QI State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu 610059China Key Laboratory of Earth Exploration and Information Techniques(Chengdu University of Technology) Ministry of EducationChengdu 610059China Research Institute of Exploration and Development Southwest Petroleum CompanySINOPECChengdu 610041China

The S-wave velocity is a critical petrophysical parameter in reservoir description,prestack seismic inversion,and geomechanical analysis.However,obtaining the S-wave velocity from field measurements is difficult.When no measured Swave data are available,petrophysical modelling provides the most accurate S-wave velocity prediction.However,because of the complexity of underground geological structures and diversity of rock minerals,the prediction results of petrophysical modelling are easily affected by factors such as the cognition and experience of the modeller.Therefore,the development of novel robust and simple S-wave velocity inversion and prediction methods independent of the modeller is critical.Inspired by ensemble learning and based on the geologic sedimentation law of reservoirs and their characteristics in logging response,an Swave velocity inversion and prediction method based on deep hybrid neural network was developed by combining the classical convolution neural network(CNN)with the long short-term memory(LSTM)network.Considering the conventional logging data such as acoustic and density as the input in the proposed method,the CNN was used to establish the nonlinear mapping relationship between the input data and S-wave velocity,and the LSTM network was used to integrate the vertical variation trend of the stratum.Thus,intelligent data-driven inversion and prediction of the S-wave velocity were realised.The experimental results revealed that the proposed method exhibited a strong generalisation ability and could obtain prediction results comparable to those of petrophysical modelling with a single-well data set for training.Thus,a novel methodology for robust and convenient S-wave velocity prediction was devised.The proposed method has considerable academic and application implications.

关键词： Deep learning Convolutional neural network Long short-term memory network Hybrid neural network Sedimentary constraint S-wave velocity prediction Petrophysical inversion

Strategies in constructing covalent organic framework membranes for molecular sieving

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Science China Chemistry 2022年第5期65卷 836-839页

作者： Jie Li Shuang Zhao Bo Wang Xiao Feng Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials Key Laboratory of Cluster ScienceMinistry of EducationFrontiers Science Center for High Energy MaterialAdvanced Technology Research Institute(Jinan)School of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China

Membrane separation has emerged as one of the most economically and environmentally friendly technologies because of its low energy consumption,small footprint,and simple operation[1].

关键词： constructing separation membranes

Study of the Flow Mechanism of Wind Turbine Blades in the Yawed Condition

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Energy Engineering 2022年第4期119卷 1379-1392页

作者： Shuang Zhao Xijun Li Jianwen Wang College of Energy and Power Engineering Inner Mongolia University of TechnologyHohhot010051China Key Laboratory ofWind Energy and Solar Energy Technology Ministry of EducationHohhot010051China Key Laboratory of Wind and Solar Energy Utilization andOptimization in Inner Mongolia Autonomous Region Hohhot010051China Beijing Jingneng International Integrated Smart Energy Co. Ltd.Beijing100073China

The computational fluid dynamics method was used to simulate the flow field around a wind turbine at the yaw angles of 0°,15°,30°,and 45°.The angle of attack and the relative velocity of the spanwise sections of the blade were extracted with the reference points method.By analyzing the pressure distribution and the flow characteristics of the blade surface,the flow mechanism of the blade surface in the yawed condition was discussed.The results showed that the variations of the angle of attack and the relative velocity were related to the azimuth angle and the radius in the yawed condition.The larger the yaw angle was,the larger the variation was.The pressure distribution in the spanwise sections was affected by both the angle of attack and the relative velocity.The angle of attack was more influential than the relative velocity.At the same yaw angle,when the angle of attack decreased,the c_(p)∼x/c curve shrunk inward and the lift force decreased.The larger the yaw angle was,the more obvious the shrink was.The effect of the yaw on the blade root region was higher than its effect on the blade tip region.

关键词： Flow characteristic angle of attack relative velocity pressure coefficient flow separation

Recent Progress on Outflow/Inflow Problem for Viscous Multi-phase Flow

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Communications on Applied Mathematics and Computation 2023年第3期5卷 987-1014页

作者： Fangfang Hao Hai-Liang Li Luyao Shang Shuang Zhao School of Mathematical Sciences Capital Normal UniversityBeijing 100048China Academy for Multidisciplinary Studies Capital Normal UniversityBeijing 100048China

According to the boundary condition with the zero,negative,or positive velocity,the initial boundary problem for compressible multi-phase flow with the Dirichlet-type boundary condition can be classified into three cases:impermeable problem,inflow problem,or outflow problem.In this paper,we review the recent progress on the existence and nonlinear stability of the stationary solution to the outflow/inflow problems for viscous multi-phase flow.

关键词： Two-phase flow-Outflow/inflow problem Stationary solution-Navier-Stokes equations

Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

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Frontiers of Structural and Civil Engineering 2023年第2期17卷 224-237页

作者： Shuang Zhao Kuihua WANG Yuan TU Weiqiu CHEN Juntao WU College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310013China

The horizontal bearing behavior of a single batter pile(SBP)is vital to its application in practical engineering;however,the horizontal responses of SBPs change with the directions of horizontal loads,and this phenomenon is rarely investigated.Therefore,the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study.Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs.Subsequently,the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element(FE)analysis.The effects of the skew angle on SBP-soil interaction are discussed.Moreover,an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle,batter angle,and pile diameter.The method is confirmed to be effective,as confirmed by the close agreement between the predicting results with the model test(reported in this study)and centrifuge model test results(reported in the literature).

关键词： single batter pile skew horizontal load model test finite-element analysis empirical design method

FeCe nanocomposite with high iron content as efficient catalyst for generation of COx-free hydrogen via ammonia decomposition

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Journal of Rare Earths 2020年第10期38卷 1053-1059,I0001页

作者： Yingqiu Gu Xiaoya Chen Shuang Zhao Yuting Zhang Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials School of Chemistry&Materials ScienceJiangsu Normal UniversityXuzhou 221116China

FeCe nanocomposite catalysts with different iron contents were synthesized by a facile co-precipitation method.The as-prepared materials were characterized by various techniques including powder X-ray diffraction(XRD),N2 adsorption/desorption and high-resolution transmission electron microscopy(HRTEM).Catalyst with the highest iron content(90 FeCe) shows the best activity for the hydrogen generation via ammonia decomposition.83% NH3 conversion is achieved at 550℃ and nearly full conversion of NH3 is realized at 600℃ with a GHSV of 24000 cm3/(gcat·h).The large content and small size crystal particles of iron species are responsible for the good catalytic performance.Temperatureprogrammed reduction by hydrogen(H2-TPR) was performed to investigate the interaction between cerium and iron species.It is found that slight cerium can exert strong interaction with iron compound thus effectively prevent the self-aggregation of active iron species,so as to improve the catalytic activity for ammonia decomposition.

关键词： FeCe nanocomposite Catalytic ammonia decomposition High iron content Hydrogen generation Rare earths

Recent Advances on Boosting the Cell Voltage of Aqueous Supercapacitors

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Nano-Micro Letters 2020年第8期12卷 60-81页

作者： Qianzhi Gou Shuang Zhao Jiacheng Wang Meng Li Junmin Xue MOE Key Laboratory of Low-Grade Energy Utilization Technologies and Systems CQU-NUS Renewable Energy Materials and Devices Joint LaboratorySchool of Energy and Power EngineeringChongqing UniversityChongqing 400044People’s Republic of China Department of Materials Science and Engineering CQU-NUS Renewable Energy Materials and Devices Joint LaboratoryNational University of SingaporeSingapore 117573Singapore

Due to its ultra-fast charge/discharge rate,long cyclic life span,and environmental benignity,aqueous supercapacitor(SC)is considered as a proper nextgeneration energy storage device.Unfortunately,limited by undesirable water electrolysis and unreasonable electrode potential range,aqueous SC normally generates a narrow cell voltage,resulting in a low energy density.To address such challenge,enormous efforts have been made to construct high-voltage aqueous SCs.Despite these achievements,the systematic reviews about this field are still rare.To fill this knowledge gap,this review summarizes the recent advances about boosting the cell voltage of aqueous SCs.From the viewpoint of electrode,doping alkali cations,modulating the electrode mass ratio,and optimizing the surface charge density are regarded as three effective pathways to achieve this goal.However,adjusting the appropriate pH level,introducing redox mediators,and constructing“water-in-salt”electrolyte are other three universal routes from the electrolyte aspect.Furthermore,it is also effective to obtain the high-voltage aqueous SCs through asymmetric design,such as designing asymmetric SCs.The confronting challenges and future development tendency towards the high-voltage aqueous SCs are further discussed.

关键词： Aqueous supercapacitors Cell voltage Electrodes Electrolytes Asymmetric design

Modulation of ionic arrangement in polar magnet by chemical pressure

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Chinese Chemical Letters 2023年第3期34卷 502-506页

作者： Shuang Zhao Jinjin Yang Yifeng Han Meixia Wu Man-Rong Li Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistrySun Yat-sen UniversityGuangzhou 510006China Institute of Semiconductors Guangdong Academy of SciencesGuangzhou 510650China

The similarity of local structure-connection pattern and volumetrically compressive strain between host and guest phases can be used to stabilize heteroid metastable matter and tune the local structure and properties.Here a series of metastable ABO_(3)(A=Mn;B=Mn_(0.5)Mo_(0.5),Mn_(1/3)Ta_(2/3),and Mn_(0.5)Ta_(0.5)) were trapped in LiTaO_(3) to form solid-solutions,where the difference of solid solubility limit reveals the barrier of size effect on chemical pressure.All samples show antiferromagnetic characters,in which the(LiTaO_(3))_(1-x)-[Mn(Mn_(0.5)Mo_(0.5))O_(3)]_(x) series exhibit more complex magnetic and dielectric behaviors with the increasing of metastable guest phase,stemming from the complex interactive mechanism between Mn^(2+)and Mo^(6+).The cell parameter variation of (LiTaO_(3))_(1-z)-[Mn(Mn_(0.5)Ta_(0.5))O_(3)]_zshows a more regularly changing tendency,on account of the smallest size barrier.These findings show that chemical pressure can effectively stimulate the physical pressure to intercept and modulate a metastable phase at atomic-scale by compressibility effect between like structures at ambient pressure.

关键词： Chemical pressure Trapping metastable-phase Cationic arrangement Antiferromagnetism Dielectricity

Review of Design and Control Optimization of Axial Flux PMSM in Renewable-energy Applications

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Chinese Journal of Mechanical Engineering 2023年第2期36卷 29-49页

作者： Jianfei zhao Xiaoying Liu shuang Wang Lixiao Zheng School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444China

Axial flux permanent magnet synchronous motors(AFPMSMs)have been widely used in wind-power generation,electric vehicles,aircraft,and other renewable-energy applications owing to their high power density,operating efficiency,and integrability.To facilitate comprehensive research on AFPMSM,this article reviews the developments in the research on the design and control optimization of AFPMSMs.First,the basic topologies of AFPMSMs are introduced and classified.Second,the key points of the design optimization of core and coreless AFPMSMs are summarized from the aspects of parameter design,structure design,and material optimization.Third,because efficiency improvement is an issue that needs to be addressed when AFPMSMs are applied to electric or other vehicles,the development status of efficiency-optimization control strategies is reviewed.Moreover,control strategies proposed to suppress torque ripple caused by the small inductance of disc coreless permanent magnet synchronous motors(DCPMSMs)are summarized.An overview of the rotor-synchronization control strategies for disc contra-rotating permanent magnet synchronous motors(CRPMSMs)is presented.Finally,the current difficulties and development trends revealed in this review are discussed.

关键词： AFPMSM Design optimization Cogging torque Efficiency optimization Control strategy optimization