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A promising approach for quantifying focal stroke modeling and assessing stroke progression:optical resolution photoacoustic microscopy photothrombosis

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Neural Regeneration Research 2025年第7期20卷 2029-2037页

作者： Xiao Liang Xingping quan Xiaorui Geng Yujing Huang Yonghua Zhao Lei Xi Zhen Yuan Ping Wang bin Liu Faculty of Health Sciences University of MacaoMacao Special Administrative RegionChina Center for Cognitive and Brain Sciences University of MacaoMacao Special Administrative RegionChina Department of Biomedical Engineering Southern University of Science and TechnologyShenzhenGuangdong ProvinceChina State Key Laboratory of Quality Research in Chinese Medicine Institute of Chinese Medical SciencesUniversity of MacaoTaipaMacao Special Administrative RegionChina Department of Emergency Zhujiang HospitalSouthern Medical UniversityGuangzhouGuangdong ProvinceChina

To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral ***,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly *** this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed *** observed the molding process in mice of different ages and presented age-dependent vascular embolism ***,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a *** imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.

关键词： age-dependent cerebral cortex ischemic stroke mouse model optical coherence tomography angiography photoacoustic microscopy photothrombosis vascular imaging

Nonlinear Mathematical Modeling and Sensitivity Analysis of Hydraulic Drive Unit

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 999-1011页

作者： KONG Xiangdong YU bin quan Lingxiao ba Kaixian WU Liujie National Engineering Research Center for Local Joint of Advanced Manufacturing Technology and Equipment Yanshan University Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University School of Mechanical Engineering Yanshan University

The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity index

关键词： nonlinear mathematical model hydraulic drive unit valve-controlled symmetrical cylinder sensitivity analysis sensitivity index

Cavitation of a Submerged Jet at the Spherical Valve Plate/Cylinder Block Interface for Axial Piston Pump

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Chinese Journal of Mechanical Engineering 2020年第5期33卷 197-211页

作者： bin Zhao Weiwei Guo Long quan College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Transducers and Intelligent Control System of Ministry of Education and Shanxi Province Taiyuan University of TechnologyTaiyuan 030024China The State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China

The spherical valve plate/cylinder block pair has the advantages of strong overturning resistance and large bearing ***,the configurations of the unloading and pre-boosting triangular grooves on the spherical valve plate are different from those in the planar valve plate,resulting in special cavitation phenomenon on the spherical port plate *** order to study cavitation characteristics of spherical port plate pair,a dynamic CFD model of the piston pump including turbulence model,cavitation model and fluid compressibility is established.A detailed UDF compilation scheme is provided for modelling of the micron-sized spherical oil film mesh,which makes up for the lack of research on the meshing of the spherical oil *** this paper,using CFD simulation tools,from the perspectives of pressure field,velocity field and gas volume fraction change,a detailed analysis of the transient evolution of the submerged cavitation jet in a axial piston pump with spherical valve plate is carried *** study indicates the movement direction of the cavitation cloud cluster through the cloud image and the velocity vector direction of the observation *** sharp decrease of velocity and gas volume fraction indicates the collapse phenomenon of bubbles on the part wall *** discoveries verify the special erosion effect in case of the spherical valve plate/cylinder block *** submerged cavitation jet generated by the unloading triangular grooves distributed on the spherical valve plate not only cause denudation of the inner wall surface of the valve plate,but also cause strong impact and denudation on the lower surface of the cylinder ***,the direction of the unloading triangular groove was modified to extend the distance between it and the wall surface which can effectively alleviate the erosion effect.

关键词： Cavitation submerged jet Spherical valve plate/cylinder block pair Axial piston pump

Critical point symmetry for odd-odd nuclei and collective multiple chiral doublet bands

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Science China(Physics,Mechanics & Astronomy) 2021年第12期64卷 111-120页

作者： Yu Zhang bin Qi Shuang-quan Zhang Department of Physics Liaoning Normal UniversityDalian 116029China Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment School of Space Science and PhysicsInstitute of Space SciencesShandong UniversityWeihai 264209China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 110871China

A critical point symmetry(CPS) for odd-odd nuclei is built in the core-particle coupling scheme with the even-even core assumed to follow the spherical to triaxially deformed shape phase transition. It is shown that the model Hamiltonian can be approximately solved with the solutions being expressed in terms of the Bessel functions of irrational orders. In particular, the CPS predicts that collective multiple chiral doublets may exist in transitional odd-odd systems.

关键词： collective model critical point symmetry multiple chiral doublet bands

A Unified Trajectory Optimization Approach for Long-Term and Reactive Motion Planning of Legged Locomotion

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Journal of Bionic Engineering 2023年第5期20卷 2108-2122页

作者： Yapeng Shi bin Yu Kaixian ba Mantian Li School of Mechanical Engineering Yanshan UniversityNo.438 West Hebei AvenueQinhuangdao066004HebeiPeople’s Republic of China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001People’s Republic of China

This paper proposes a unified trajectory optimization approach that simultaneously optimizes the trajectory of the center of mass and footholds for legged *** on a generic point-mass model,the approach is formulated as a nonlinear optimization problem,incorporating constraints such as robot kinematics,dynamics,ground reaction forces,obstacles,and target *** unified optimization approach can be applied to both long-term motion planning and the reactive online planning through the use of model predictive control,and it incorporates vector field guidance to converge to the long-term planned *** effectiveness of the approach is demonstrated through simulations and physical experiments,showing its ability to generate a variety of walking and jumping gaits,as well as transitions between them,and to perform reactive walking in obstructed environments.

关键词： Legged locomotion Motion planning Trajectory optimization Bionic robot

3D finite element simulation of microstructure evolution in blade forging of Ti-6Al-4V alloy based on the internal state variable models

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International Journal of Minerals,Metallurgy and Materials 2012年第2期19卷 122-130页

作者： Jiao Luo bin Wu Miao-quan Li School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'an 710072China

The physically-based internal state variable （ISV） models were used to describe the changes of dislocation density, grain size, and flow stress in the high temperature deformation of titanium alloys in this study. The constants of the present models could be identified based on experimental results, which were conducted at deformation temperatures ranging from 1093 K to 1303 K, height reductions ranging from 20% to 60%, and the strain rates of 0.001, 0.01, 0.1, 1.0, and 10.0 s-1. The physically-based internal state variable models were implemented into the commercial finite element （FE） code. Then, a three-dimensional （3D） FE simulation system coupling of deformation, heat transfer, and microstructure evolution was developed for the blade forging of Ti-6Al-4V alloy. FE analysis was carried out to simulate the microstructure evolution in the blade forging of Ti-6Al-4V alloy. Finally, the blade forging tests of Ti-6Al-4V alloy were performed to validate the results of FE simulation. According to the tensile tests, it is seen that the mechanical properties, such as tensile strength and elongation, satisfy the application requirements well. The maximum and minimum differences between the calculated and experimental grain size of primary α phase are 11.71% and 4.23%, respectively. Thus, the industrial trials show a good agreement with FE simulation of blade forging.

关键词： titanium alloys forging microstructure evolution internal state variables mechanical properties

On Modeling Drilling Load in Lunar Regolith Simulant

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Chinese Journal of Mechanical Engineering 2018年第1期31卷 41-52页

作者： Qi-quan quan Chong-bin Chen Zong-quan Deng Jun-Yue Tang De-Wei Tang State Key Laboratory of Robotics and System Harbin Institute of Technology

Drilling and coring, as effective ways to obtain lunar regolith along the longitudinal direction, are widely applied in the lunar sampling field. Conventionally, modeling of drill-soil interaction was divided into soil cutting and screw conveyance processes, ignoring the differences in soil mechanical properties between them. To improve the modeling accuracy, a hypothesis that divides the drill-soil interaction into four parts: cuttings screw conveyance, cuttings extruding, cuttings bulldozing, and in situ simulant cutting, is proposed to establish a novel model based on the passive earth pressure theory. An iterative numerical calculation method is developed to predict the drilling loads. A drilling and coring testbed is developed to conduct experimental tests. Drilling experiments indicate that the drilling loads calculated by the proposed model match well the experimental results. The proposed research provides the instructions to adopt a suitable drilling strategy to match the rotary and penetrating motions, to increase the safety and reliability of drilling control in lunar sampling missions.

关键词： Lunar regolith drilling Lunar regolith simulant Drill-simulant interaction Screw conveyance

Modeling,Simulation and Experiment of Electro-hydraulic Screw Down Servo System of Seamless Tube Rolling Mill

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Chinese Journal of Mechanical Engineering 2011年第1期24卷 113-120页

作者： XU Xiaoqing quan Long LI bin GUO Jibao Institute of Mechatronics Engineering Taiyuan University of Technology Taiyuan 030024 China Taiyuan Tongze Heavy Industry Co. Ltd. Taiyuan 030032 China

Electro-hydraulic screw down servo system（HSDS） is widely used in seamless tube rolling mill in western *** in Chinese companies,mechanical screw down system（MSDS） is popularly equipped and has a serious disadvantage that the roller would often be locked when it is *** the purpose of designing the first set of domestic twin-roller,four-cylinder and six-framework electro-hydraulic HSDS of seamless tube rolling mill,an experiment system that can simulate the process of seamless tube rolling is constructed.A digital simulation model of the experiment system is built with AMESim software and validated by comparing the simulation results with experiment *** sudden load response of the screw piston position is studied with the built model and the experiment *** improve the HSDS＇s positioning accuracy with large load,a hybrid control scheme of combining load disturbance feedforward compensation（LDFC） method based on servo valve＇s pressure-stroke feature and anti-saturation integral control（ASIC） is *** results of simulation and experiment indicate that the transient response time of the single-roller HSDS with the proposed scheme decreases from 0.65 s to less than 0.2 s without static *** improve the system dynamic stiffness and production qualified rate,a flow rate feedforward compensation（FFC） control strategy based on oil compressibility to dynamic position error is *** FFC strategy is validated with experiments in which the transient error caused by sudden load is reduced to less than 25% of that without *** extending the simulation model to HSDS of a twin-roller,four-cylinder rolling mill,analyzing the mill deformation,and applying the LDFC,ASIC and FFC to the HSDS,the dynamic performance and positioning accuracy of compensated multi-roller HSDS at biting moment are *** research results provide a theoretical and experimental basis for the design of HSDS of seamless steel tube rolling mill.

关键词： tube rolling mill servo system digital simulation load stiffness

Evaluation of fault stability and seismic potential for Hutubi underground gas storage due to seasonal injection and extraction

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Underground Space 2023年第6期13卷 74-85页

作者： Cexuan Liu Fengshou Zhang quan Wang bin Wang Qi Zhang bin Xu Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical&Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China China National Petroleum Company Xinjiang Oil FieldKaramayXinjiang 834000China School of Civil Engineering Southeast UniversityNanjing 211189China Origin Geomechanics Inc. CalgaryAlbertaT3H 0X6Canada Department of Civil Engineering University of CalgaryCalgaryAlbertaT2N 1N4Canada

The Hutubi gas field was put into production in 1998 and then converted into an underground gas storage(UGS)facility in 2013,and since then a cluster of earthquakes associated with seasonal injection and extraction activities have been recorded *** evaluate the fault stability and seismic potential,we established a pseudo-3D geomechanical model to simulate the process of seasonal injection and *** pore pressures from 1998 to 2019 were obtained through multiphase reservoir simulation and validated by history matching the field injection and production *** then imported pore pressures into the geomechanical model to simulate the poroelastic perturbation on faults for over 20 *** fidelity of this model was validated by comparing the simulated surface deformation with global positioning system(GPS)measured *** used Coulomb failure stress(CFS)as the indicator for the likelihood of fault *** simulation results show that the location of the induced earthquake cluster was within the positive Coulomb stress perturbation(DCFS)area,in which fault slippage was *** addition,DCFS at the earthquake location kept increasing after the injection *** findings could explain the induced earthquakes with the Coulomb failure stress ***,we conducted a parameter sensitivity study on the dominant factors such as the maximum operating pressure(MOP),frictional coefficient,and dip angle of the pre-existing *** results indicate that the magnitude of DCFS caused by seasonal injection and extraction decreases with distance;MOPs are constrained to 32.9,36.2,and 39.5 MPa according to different DCFS thresholds;the critical dip angle ranges are 0-20°and 80°-100°;and strengthening the fault friction can either increase or decrease the seismic *** study can help determine the MOP for Hutubi underground gas storage(HTB UGS)and provide a framework for simulating the potential causes of induced seismicity for othe

关键词： Underground gas storage Fault stability Seismic potential GPS Induced earthquake Coulomb stress perturbation