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Review:Advances in research of stress-assisted corrosion fatigue problem

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 221-227页

作者： tang Zhi-bo LI qiang Division of Engineering Zhejiang Ocean University Zhoushan 316004 China

Ceramic materials are notable for their rigidity, insulation and resistance to hostile environment, Nevertheless, if a stressed ceramic component is exposed to chemical attack, it may suffer from a form of delayed fracture known as static fatigue. From the point of view of a designer, it is clearly desirable to determine the behavior of sub-critical crack growth; the crack path and crack growth rate, as a function of material properties and loading conditions are of particular interest. This paper presents a review of advances in stress assisted corrosion problem in history and its corresponding numerical approaches in the last decades, and finally, comes uo with consideration and crucial suggestions for future work.

关键词： Stress corrosion Finite element method (FEM) Fracture Static fatigue Meshless local Petrov-Galerkin (MLPG)

New Insights into the Dysfunctions of Pericytes and Neurovascular Units in Neurodegenerative Diseases

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Neuroscience Bulletin 2020年第12期36卷 1570-1572页

作者： Qing Liu wei-Jye Lin Yamei tang Department of Neurology Sun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou 510120China Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation Medical Research CenterSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou 510120China

The neurovascular unit(NVU)is an essential anatomical and physiological entity for the maintenance of brain homeostasis and function;it is composed of endothelial cells,pericytes,astrocytes,neurons,vascular smooth muscle cells,microglia,and oligodendroglia[1].The NVU regulates important brain vessel properties such as the integrity of the blood-brain barrier(BBB)and cerebral blood flow(CBF).Considerable efforts have been made to investigate the cerebral microcirculatory dysfunction in ageing and Alzheimer’s disease(AD)[2].

关键词： homeostasis integrity maintenance

A new 3D plastoelastohydrodynamic lubrication model for rough surfaces

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Friction 2024年第6期12卷 1176-1193页

作者： Shengyu YOU Jinyuan tang qiang WANG State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China

Plastoelastohydrodynamic lubrication of rough surfaces(R-PEHL)is a cutting-edge area of research in interface fluid-structure coupling *** existing R-PEHL model calculates the elastic-plastic deformation of rough surface by the Love equation in a semi-infinite space smooth surface,which deviates from the actual ***,it is an innovative work to study the exact solution of elastic-plastic deformation of rough surface and its influence on the solution results of R-PEHL *** this paper,a new contact calculation model of plastoelastohydrodynamic lubrication(PEHL)with three-dimensional(3D)rough surface is proposed by integrating numerical method of EHL and finite element *** new model eliminates an original error introduced by the assumption of semi-infinite space in contact calculation,providing wide applicability and high *** the given rough surfaces and working conditions,the study reveals that:(1)the oil film pressure calculated by the new model is lower than that of the smooth surface in semi-infinite space by 200–800 MPa;(2)the Mises stress of the new model is 2.5%–26.6%higher than that of the smooth surface in semi-infinite space;(3)compared with the semi-infinite space assumption,the rough surface plastic deformation of the new model is increased by 71%–173%,and the local plastic deformation singularity may appear under the semi-infinite space assumption;(4)the plastic deformation caused by the first contact cycle on the rough surface of the new model accounts for 66.7%–92.9%of the total plastic deformation,and the plastic deformation of the semi-infinite space accounts for 50%–83.3%.This study resolves the contradiction between the smooth surface assumption and the rough surface in the existing R-PEHL model,establishing a solid logic foundation for the accurate solution of R-PEHL model.

关键词： rough surface plastoelastohydrodynamic lubrication(PEHL) asperity plastic deformation semi-infinite space

Effect of statins type on incident prostate cancer risk： a meta-analysis and systematic review

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Asian Journal of Andrology 2017年第6期19卷 666-671页

作者： Ping Tan Chen Zhang Shi-You wei Zhuang tang Liang Gao Lu Yang qiang wei Department of Urology West China Hospital Sichuan University Chengdu China Institute of Urology West China Hospital Sichuan University Chengdu China Department of Cardiology West China Hospital Sichuan University Chengdu China Department of Cardiovascular and Thoracic Surgery West China Hospital Sichuan University Chengdu China

The aim of this study is to investigate the effect of statins type or even when grouping statins by hydrophilic or hydrophobic nature on prostate cancer risk. A literature search was performed without language restrictions using the databases of PubMed （1984.1-2015.3）, MEDLINE （1984.1-2015.3）, and EMBASE （1990.1-2015.3）. Two independent reviewers appraised eligible studies and extracted data. weighted averages were reported as relative risk （RR） with 95% confidence intervals （CI）. Statistic heterogeneity scores were assessed with the standard Cochran＇s Q-test and F statistic, Publication bias was detected using the Begg＇s and Egger＇s tests. All statistical analyses were conducted by STATA version 10. Finally, fourteen studies were included in the meta-analysis. Both hydrophilic and hydrophobic statins showed no association with incidence of prostate cancer （RR = 1.00, 95% Ch 0.82-1.17; RR = 0.90, 95% CI： 0.73-1.08, respectively）. Meanwhile, the risk of prostate cancer was not reduced in simvastatin （RR = 0.89, 95% CI- 0.72-1.05）, pravastatin （RR = 1.02, 95% Ch 0.94-1.11）, atorvastatin （RR = 0.89, 95% CI： 0.76-1.02）, fluvastatin （RR = 0.99, 95% Ch 0.97-1.01）, or Iovastatin users （RR = 0.94, 95% CI： 0.79-1.08）. The funnel plot showed that there was no publication bias. The results showed that statins had a neutral effect on prostate cancer risk; hydrophilic and hydrophobic statins as well as any subtype of statins did not affect the risk of prostate cancer.

关键词： meta-analysis prostate cancer statins type systematic review

Three new carabrane sesquiterpenoid derivatives from the whole plant of Carpesium abrotanoides L.

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Chinese Journal of Natural Medicines 2021年第11期19卷 868-873页

作者： WU Jie-wei tang Chun-Ping YAO Sheng KE Chang-qiang YE Yang Mathematical Engineering Academy of Chinese Medicine Guangzhou University of Chinese MedicineGuangzhou 510006China State Key Laboratory of Drug Research and Natural Products Chemistry DepartmentShanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China School of Life Science and Technology Shanghai Tech UniversityShanghai 201203China

Dicarabrols B and C(1 and 2),two new carabrane sesquiterpenoid dimers,along with one new carabrane sesquiterpenoid(3)were isolated from the whole plant of Carpesium abrotanoides *** full structures were established by extensive analysis of HR-ESI-MS and NMR spectroscopic data,and time-dependent density functional theory(TDDFT)electronic circular dichroism(ECD)*** B possesses a novel C30 skeleton featuring a methylene-tethered bridge between two sesquiterpene moieties,while dicarabrol C presents the unique linkage of a cyclopentane ring in the *** C exhibited potent inhibitory effects on HL−60 cells with an IC50 value of 3.7μmol·L^(−1).

关键词： Sesquiterpenoid dimer Carpesium abrotanoides L. Carabrane sesquiterpenoid Dicarabrol B Dicarabrol C 11R-hydroxycarabrol

Rotational manipulation of massive particles in a 2D acoustofluidic chamber constituted by multiple nonlinear vibration sources

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Chinese Physics B 2022年第4期31卷 361-372页

作者： qiang tang Pengzhan Liu Shuai tang Jiangsu Provincal Engineering Research Center for Biomedical Materials and Advanced Medical Devices Faculty of Mechanical and Material EngineeringHuaiyin Institute of TechnologyHuaian 223003China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Key Laboratory of Advanced Manufacturing Technology Faculty of Mechanical and Material EngineeringHuaiyin Institute of TechnologyHuaian 223003China

Rotational manipulation of massive particles and biolo gical samples is essential for the development of miniaturized lab-on-a-chip platforms in the fields of chemical,medical,and biological *** this paper,a device concept of a two-dimensional acoustofluidic chamber actuated by multiple nonlinear vibration sources is *** functional chamber enables the generation of acoustic streaming vortices for potential applications that include strong mixing of multiphase flows and rotational manipulation of micro-/nano-scale objects without any rotating *** numerical simulations,we find that diversified acoustofluidic fields can be generated in the chamber under various actuations,and massive polystyrene beads inside can experience different acoustophoretic motions under the combined effect of an acoustic radiation force and acoustic ***,we investigate and clarify the effects of structural design on modulation of the acoustofluidic fields in the *** believe the presented study could not only provide a promising potential tool for rotational acoustofluidic manipulation,but could also bring this community some useful design insights into the achievement of desired acoustofluidic fields for assorted microfluidic applications.

关键词： acoustic streaming acoustofluidics ultrasonic vibration rotational manipulation

Research on End-force Output of 8-cable Driven Parallel Manipulator

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International Journal of Automation and computing 2020年第3期17卷 378-389页

作者： Sen-Hao Hou Xiao-qiang tang Ling Cao Zhi-wei Cui Hai-Ning Sun Ying-wei Yan State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China Postal Scientific Research and Planning Academy Beijing 100096China

The return capsule needs to be launched to the moon and return back to earth in the third stage of the Chinese lunar exploration ***,it is necessary to perform simulations on the *** paper presents an 8-cable-driven parallel manipulator to achieve end-force output in a low-gravity ***-force output refers to the vector sum of the external force on the end-effector.A model of end-force output is established based on a kinematics model,a dynamic model,and a force analysis of an 8-cable driven parallel *** obtain end-force output in a low-gravity environment,the cable force has to be controlled to counteract *** addition,a force-position mix control strategy is proposed to proactively control the cable force according to the force optimal distribution given by the closed-form force distribution ***,a suitable choice for an end-force output is obtained by modeling the effect of cable force on end-force *** results show that the actual cable force agrees well with the calculated force distribution,indicating that it is feasible to realize end-force output in a low gravity environment.

关键词： Cable driven parallel manipulators low gravity environment end force output cable force control mix control strategy

Coupled Lagrangian impingement spray model for doublet impinging injectors under liquid rocket engine operating conditions

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Chinese Journal of Aeronautics 2017年第4期30卷 1391-1406页

作者： qiang wei Guozhu LIANG School of Astronautics Beihang University Beoing 100083 China

To predict the effect of the liquid rocket engine combustion chamber conditions on the impingement spray, the conventional uncoupled spray model for impinging injectors is extended by considering the coupling of the jet impingement process and the ambient gas field. The new coupled model consists of the plain-orifice sub-model, the jet-jet impingement sub-model and the droplet collision sub-model. The parameters of the child droplet are determined with the jet-jet impingement sub-model using correlations about the liquid jet parameters and the chamber *** overall model is benchmarked under various impingement angles, jet momentum and offcenter ratios. Agreement with the published experimental data validates the ability of the model to predict the key spray characteristics, such as the mass flux and mixture ratio distributions in quiescent air. Besides, impinging sprays under changing ambient pressure and non-uniform gas flow are investigated to explore the effect of liquid rocket engine chamber conditions. First, a transient impingement spray during engine start-up phase is simulated with prescribed pressure profile. The minimum average droplet diameter is achieved when the orifices work in cavitation state, and is about 30% smaller than the steady single phase state. Second, the effect of non-uniform gas flow produces off-center impingement and the rotated spray fan by 38°. The proposed model suggests more reasonable impingement spray characteristics than the uncoupled one and can be used as the first step in the complex simulation of coupling impingement spray and combustion in liquid rocket engines.

关键词： Combustion chamber Doublet impinging injector Impingement spray model Lagrangian method Liquid rocket engine

Kinematics-based four-state trajectory tracking control of a spherical mobile robot driven by a 2-DOF pendulum

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Chinese Journal of Aeronautics 2019年第6期32卷 1530-1540页

作者： wei LI qiang ZHAN Robotics Institute Beihang UniversityBeijing 100083China Ecole Centrale de Pékin Beihang UniversityBeijing 100083China

Spherical mobile robot has compact structure, remarkable stability, and flexible motion,which make it have many advantages over traditional mobile robots when applied in those unmanned environments, such as outer planets. However, spherical mobile robot is a special highly under-actuated nonholonomic system, which cannot be transformed to the classic chained form. At present, there has not been a kinematics-based trajectory tracking controller which could track both the position states and the attitude states of a spherical mobile robot. In this paper, the four-state(two position states and two attitude states) trajectory tracking control of a type of spherical mobile robot driven by a 2-DOF pendulum was studied. A controller based on the shunting model of neurodynamics and the kinematic model was deduced, and its stability was demonstrated with Lyapunov’s direct method. The control priorities of the four states were allocated according to the magnification of each state tracking error in order to firstly ensure the correct tracking of the position states. The outputs(motor speeds) of the controller were regulated according to the maximum speeds and the maximum accelerations of the actuation motors in order to solve the speed jump problem caused by initial state errors, and continuous and bounded outputs were obtained. The effectiveness including the anti-interference ability of the proposed trajectory tracking controller was verified through MATLAB simulations.

关键词： Kinematics Lyapunov methods Neurodynamics Nonholonomic systems Spherical mobile robot Trajectory tracking