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Controls of strike-slip fault on fractures:Insight from 3D discrete element simulation

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Science China Earth Sciences 2024年第1期67卷 146-164页

作者： Lianbo ZENG Zhe MAO guoping liu He TIAN Yingtao YAO Kewei ZU Shaoqun DONG Mehdi OSTADHASSAN State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing 102249China College of Geosciences China University of Petroleum(Beijing)Beijing 102249China Institute of Energy Peking UniversityBeijing 100871China Exploration and Development Research Institute Zhongyuan Oilfield Branch CompanySINOPECZhengzhou 457001China Northeast Petroleum University Daqing 163318China

The fracture-cave reservoirs controlled by strike-slip faults are the main targets for oil and gas exploration of ultradeep carbonate in the Tarim Basin.It is of great significance to clarify the distribution rules of fractures related to strike-slip faults for guiding the exploration and development of ultra-deep oil and gas.In this study,six groups of strike-slip fault 3D models based on discrete element numerical simulation method have been created to investigate characteristics of fault-related fracture development and distribution law.In addition,we compared the modeling results to the measurement of fractures from the outcrop of a strike-slip fault in the Northern Tarim Basin to verify their validity.The results show that the stress environment is stable in the simple strike-slip section,and fractures intersecting with the strike-slip direction at a small angle are the principal fracture.In the releasing stepover and double-bend sections,the maximum principal stress changes from horizontal to vertical during the formation of pull-apart zones,where the principal fractures intersect the strike-slip direction at a large angle.The maximum principal stress in the restraining stepover and double-bend section remains horizontal,but their strikes change significantly with the increment of fault displacement.Thus,fractures intersecting the strike-slip direction at a small angle will become principal fractures early on,while those parallel to or anti-intersecting the strike-slip direction at a small angle will become principal fractures later.There are obvious differences in the development of fractures in different structural positions of strike-slip faults.Fractures are mainly concentrated in the fault tips,connections,and fault plane,and the magnitude of the fault damage zone is relatively larger in the first two.Compared with fault displacement,the principal damage zone(PDZ)shows stronger control on the distribution and development intensity of fractures.With the increment of fault displacement,the width of the f

关键词： Strike-slip fault Fault-related fracture Stepover Double-bend Discrete element method

BMP7 expression in mammalian cortical radial glial cells increases the length of the neurogenic period

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Protein & Cell 2024年第1期15卷 21-35页

作者： Zhenmeiyu Li guoping liu Lin Yang Mengge Sun Zhuangzhi Zhang Zhejun Xu Yanjing Gao Xin Jiang Zihao Su Xiaosu Li Zhengang Yang State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Institutes of Brain Scienceand Department of NeurologyZhongshan HospitalFudan UniversityShanghai 200433China

The seat of human intelligence is the human cerebral cortex,which is responsible for our exceptional cognitive abilities.Identifying principles that lead to the development of the large-sized human cerebral cortex will shed light on what makes the human brain and species so special.The remarkable increase in the number of human cortical pyramidal neurons and the size of the human cerebral cortex is mainly because human cortical radial glial cells,primary neural stem cells in the cortex,generate cortical pyramidal neurons for more than 130 days,whereas the same process takes only about 7 days in mice.The molecular mechanisms underlying this difference are largely unknown.Here,we found that bone morphogenic protein 7(BMP7)is expressed by increasing the number of corti-cal radial glial cells during mammalian evolution(mouse,ferret,monkey,and human).BMP7 expression in cortical radial glial cells promotes neurogenesis,inhibits gliogenesis,and thereby increases the length of the neurogenic period,whereas Sonic Hedgehog(SHH)signaling promotes cortical gliogenesis.We demonstrate that BMP7 sign-aling and SHH signaling mutually inhibit each other through regulation of GLI3 repressor formation.We propose that BMP7 drives the evolutionary expansion of the mammalian cortex by increasing the length of the neurogenic period.

关键词： radial glia cortical neurogenesis cortical gliogenesis cortical evolution BMP7 SHH

A review on ultra-small undoped MoS_(2) as advanced catalysts for renewable fuel production

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Carbon Energy 2024年第2期6卷 92-112页

作者： guoping liu Lingling Ding Yuxuan Meng Ahmad Ali Guifu Zuo Xianguang Meng Kun Chang Oi Lun Li Jinhua Ye Hebei Provincial Laboratory of Inorganic Nonmetallic Materials College of Materials Science and EngineeringNorth China University of Science and TechnologyTangshanChina College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjingChina School of Materials Science and Engineering Pusan National UniversityBusanKorea International Center for Materials Nanoarchitectonics(WPIMANA) National Institute for Materials Science(NIMS)1-1 NamikiTsukubaIbarakiJapan

Molybdenum disulfide(MoS_(2))has garnered significant attention in the field of catalysis due to the high density of active sites in its unique two-dimensional(2D)structure,which could be developed into numerous high-performance catalysts.The synthesis of ultra-small MoS2 particles(<10 nm)is highly desired in various experimental studies.The ultra-small structure could often lead to a distinct S-Mo coordination state and nonstoichiometric composition in MoSx,minimizing in-plane active sites of the 2D structure and making it probable to regulate the atomic and electronic structure of its intrinsic active sites on a large extent,especially in MoSx clusters.This article summarizes the recent progress of catalysis over ultra-small undoped MoS_(2) particles for renewable fuel production.Through a systematic review of their synthesis,structural,and spectral characteristics,as well as the relationship between their catalytic performance and inherent defects,we aim to provide insights into catalysis over this matrix that may potentially enable advancement in the development of high-performance MoS_(2)-based catalysts for sustainable energy generation in the future.

关键词： applications catalytic MoS_(2) structure synthesis

Developmental Origins of Human Cortical Oligodendrocytes and Astrocytes

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Neuroscience Bulletin 2022年第1期38卷 47-68页

作者： Lin Yang Zhenmeiyu Li guoping liu Xiaosu Li Zhengang Yang State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Institutes of Brain ScienceInstitute for Translational Brain Researchand Department of NeurologyZhongshan HospitalFudan UniversityShanghai200032China

Human cortical radial glial cells are primary neural stem cells that give rise to cortical glutaminergic projection pyramidal neurons, glial cells (oligodendrocytes and astrocytes) and olfactory bulb GABAergic interneurons. One of prominent features of the human cortex is enriched with glial cells, but there are major gaps in understanding how these glial cells are generated. Herein, by integrating analysis of published human cortical single-cell RNA-Seq datasets with our immunohistochemistical analyses, we show that around gestational week 18, EGFR-expressing human cortical truncated radial glial cells (tRGs) give rise to basal multipotent intermediate progenitors (bMIPCs) that express EGFR, ASCL1, OLIG2 and OLIG1. These bMIPCs undergo several rounds of mitosis and generate cortical oligodendrocytes, astrocytes and olfactory bulb interneurons. We also characterized molecular features of the cortical tRG. Integration of our findings suggests a general picture of the lineage progression of cortical radial glial cells, a fundamental process of the developing human cerebral cortex.

关键词： Radial glial cell Intermediate progenitor cell EGFR HOPX Oligodendrocyte Astrocyte Olfactory bulb interneuron Cerebral cortex Human

A stability locomotion-control strategy for quadruped robots with center-of-mass dynamic planning

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第6期24卷 516-530页

作者： Yangyang HAN guoping liu Zhenyu LU Huaizhi ZONG Junhui ZHANG Feifei ZHONG Liyu GAO School of Advanced Manufacturing Nanchang UniversityNanchang 330031China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310058China

Locomotion stability is essential for controlling quadruped robots and adapting them to unstructured terrain.We propose a control strategy with center-of-mass(CoM)dynamic planning for the stable locomotion of these robots.The motion trajectories of the swing legs are synchronized with the CoM of the robot.To implement the synchronous control scheme,we adjusted the swing legs to form a support triangle.The strategy is applicable to both static walk gait and dynamic trot gait.In the motion control processes of the robot legs,the distribution of the ground reaction forces is optimized to minimize joint torque and locomotion energy consumption.We also used an improved joint-torque controller with varied controller coefficients in the stance and swing phases.The simulation and experimental results demonstrate that the robot can complete omnidirectional locomotion in both walk and trot gaits.At a given locomotion speed,the stability margins for the robot during walking and trotting were 27.25%and 37.25%higher,respectively,than in the scheme without CoM planning.The control strategy with energy consumption optimization(ECO)reduced the energy consumption of the robot in walk and trot gaits by 11.25%and 13.83%,respectively,from those of the control scheme without ECO.

关键词： Center-of-mass(CoM)planning Quadruped robot Cooperative scheme Ground reaction forces Stability margin

Contact detection with multi-information fusion for quadruped robot locomotion under unstructured terrain

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Frontiers of Mechanical Engineering 2023年第3期18卷 145-164页

作者： Yangyang HAN Zhenyu LU guoping liu Huaizhi ZONG Feifei ZHONG Shengyun ZHOU Zekang CHEN School of Advanced Manufacturing Nanchang UniversityNanchang 330031China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China

Reliable foot-to-ground contact state detection is crucial for the locomotion control of quadruped robots in unstructured environments.To improve the reliability and accuracy of contact detection for quadruped robots,a detection approach based on the probabilistic contact model with multi-information fusion is presented to detect the actual contact states of robotic feet with the ground.Moreover,a relevant control strategy to address unexpected early and delayed contacts is planned.The approach combines the internal state information of the robot with the measurements from external sensors mounted on the legs and feet of the prototype.The overall contact states are obtained by the classification of the model-based predicted probabilities.The control strategy for unexpected foot-to-ground contacts can correct the control actions of each leg of the robot to traverse cluttered environments by changing the contact state.The probabilistic model parameters are determined by testing on the single-leg experimental platform.The experiments are conducted on the experimental prototype,and results validate the contact detection and control strategy for unexpected contacts in unstructured terrains during walking and trotting.Compared with the body orientation under the time-based control method regardless of terrain,the root mean square errors of roll,pitch,and yaw respectively decreased by 60.07%,54.73%,and 64.50%during walking and 73.40%,61.49%,and 61.48%during trotting.

关键词： multi-information fusion contact detection quadruped robot probabilistic contact model unstructured terrain

Predictive Tracking Control of Network-Based Agents With Communication Delays

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IEEE/CAA Journal of Automatica Sinica 2018年第6期5卷 1150-1156页

作者： Tianyong Zhang guoping liu School of Automation Harbin University of Science and TechnologyHarbin 150080 CTGT Center School of Astronautics Harbin Institute of TechnologyHarbin 150001China School of Engineering University of South Wales PontypriddCF37 1DLUK

This paper investigates the remote tracking control problem of Network-based Agents with communication delays existing in both forward and feedback communication channels.A networked predictive tracking controller is proposed to compensate the negative effects caused by bilateral time-delays in a wireless network. Furthermore, the problem of consecutive data loss in the feedback channel is solved using aforementioned controller, where lateral movement perturbations are introduced.Simulations and experiments are provided for several cases,which verify the realizability and effectiveness of the proposed controller.

关键词：反馈通信信道自动化技术发展现状

时变通信约束下航天器绕飞的高阶全驱预测控制方法

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航空学报 2024年第1期45卷 40-50页

作者：张大蔚刘国平哈尔滨工业大学控制理论与制导技术研究中心哈尔滨150001 南方科技大学控制科学与技术研究中心深圳518055

针对视线坐标系下具有时变通信约束的航天器绕飞问题,提出了一种高阶全驱(HOFA)预测控制方法以实现绕飞任务并主动补偿服务航天器与跟踪与数据中继卫星系统间的时变通信延迟和数据丢包。首先,在视线坐标系下引入了一个非线性高阶全驱系... 详细信息

针对视线坐标系下具有时变通信约束的航天器绕飞问题,提出了一种高阶全驱(HOFA)预测控制方法以实现绕飞任务并主动补偿服务航天器与跟踪与数据中继卫星系统间的时变通信延迟和数据丢包。首先,在视线坐标系下引入了一个非线性高阶全驱系统模型来描述航天器绕飞的相对动力学模型,并将所提出的绕飞任务转换为非线性高阶全驱系统的跟踪控制问题。其次,利用全驱特性抵消系统中的非线性,从而构建一个线性高阶全驱(LIHOFA)系统。然后,应用丢番图方程建立一个增量线性高阶全驱预测模型以代替传统的降阶预测模型,进而构建多步超前预测以实现跟踪控制性能的优化和时变通信约束的补偿,从而有效地保证了绕飞任务的实现。同时,给出了一个简单的充要条件以分析闭环系统的稳定性和跟踪性能。最后,还提供了航天器在圆轨道和椭圆轨道绕飞的数值仿真以验证高阶全驱预测控制方法的可行性。

关键词：航天器绕飞非线性高阶全驱系统时变通信约束高阶全驱预测控制稳定性与跟踪性能

Engineering the viscoelasticity of gelatin methacryloyl(GelMA)hydrogels via small“dynamic bridges”to regulate BMSC behaviors for osteochondral regeneration

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Bioactive Materials 2023年第7期25卷 445-459页

作者： Changjiang liu Qifan Yu Zhangqin Yuan Qianping Guo Xiting Liao Feng Han Tao Feng guoping liu Runze Zhao Zhuang Zhu Haijiao Mao Caihong Zhu Bin Li College of Chemistry Chemical Engineering and Materials ScienceOrthopaedic InstituteDepartment of Orthopaedic SurgeryThe First Affiliated HospitalSuzhou Medical CollegeSoochow UniversitySuzhouJiangsuChina Department of Orthopaedic Surgery The Affiliated Hospital of Medical SchoolNingbo UniversityNingboZhejiangChina Collaborative Innovation Center of Hematology Soochow UniversitySuzhouJiangsuChina

The dynamic extracellular matrix(ECM)constantly affects the behaviors of cells.To mimic the dynamics of ECM with controllable stiffness and energy dissipation,this study proposes a strategy in which a small molecule,3,4-dihydroxybenzaldehyde(DB),was used as fast"dynamic bridges"to construct viscoelastic gelatin methacryloyl(GelMA)-based hydrogels.The storage modulus and loss modulus of hydrogels were independently adjusted by the covalent crosslinking density and by the number of dynamic bonds.The hydrogels exhibited self-healing property,injectability,excellent adhesion and mechanical properties.Moreover,the in vitro results revealed that the viscous dissipation of hydrogels favored the spreading,proliferation,osteogenesis and chondrogenesis of bone marrow mesenchymal stem cells(BMSCs),but suppressed their adipogenesis.RNA-sequencing and immunofluorescence suggested that the viscous dissipation of hydrogels activated Yes-associated protein(YAP)by stabilizing integrinβ1,and further promoted nuclear translocation of smad2/3 andβ-catenin to enhance chondrogenesis and osteogenesis.As a result,the viscoelastic GelMA hydrogels with highest loss modulus showed best effect in cartilage and subchondral bone repair.Taken together,findings from this study reveal an effective strategy to fabricate viscoelastic hydrogels for modulating the interactions between cells and dynamic ECM to promote tissue regeneration.

关键词： Viscoelastic hydrogels Dynamic bonds GelMA Dissipation Osteochondral regeneration