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Buckling of filamentous actin bundles in filopodial protrusion

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Acta Mechanica Sinica 2019年第2期35卷 365-375页

作者： yanzhong wang Jin Qian Department of Engineering Mechanics Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Hangzhou Zhejiang 310027 China

The mechanical behaviors of filamentous actin (F-actin) bundles play an essential role in filopodial protrusions at the leading edge of crawling cells. These bundles consist of parallel actin filaments that are hexagonally packed and interconnected via cross-linking proteins including α-actinin, filamin, and fascin. As pushing against the plasma membrane and/or external barriers, the actin bundles in filopodial protrusion inevitably encounter a compressive load. The bending stiffness and buckling stability of actin bundles are therefore important in determining the filopodia architecture and subsequent cell morphology. In this work, we employ a coarse-grained molecular dynamics model to investigate the buckling behaviors of cross-linked actin bundles under compression, which explicitly accounts for the properties of constituent filaments and the mechanical descriptions of cross-linkers. The bending stiffness of actin bundles exhibits a generic size effect depending on the number of filaments in the bundles, explicitly depending on the degree of inter-filament coupling. The distinct buckling modes are analyzed for bundles with different coupling states and strengths of cross-linkers. This study could clarify the stability and buckling mechanisms of parallelly packed actin bundles and the structure-function relations of mechanical components in filopodial protrusion.

关键词： Filopodial protrusion Actin bundle Molecular dynamics Buckling Size effect Cross-linking protein

Effects of domain unfolding and catch-like dissociation on the collective behavior of integrin-fibronectin bond clusters

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Acta Mechanica Sinica 2021年第2期37卷 229-243页

作者： Ji Lin yanzhong wang Jin Qian Department of Engineering Mechanics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang UniversityHangzhou 310027China

To gain more understanding of cell-matrix adhesion,we consider an idealized theoretical model of a cluster of integrin-fibronectin bonds at the cell-matrix interface subjected to a dynamic *** distributions of bond traction and interfacial deformation are assumed to obey classical elastic equations,whereas the dissociation/association of individual bonds as well as unfolding/refolding of fibronectin domains are described by stochastic *** stochastic-elasticity coupling,we perform Monte Carlo simulations to investigate how the collective behavior and adhesion performance of the integrin-fibronectin-mediated interface are influenced by two characteristics newly incorporated in the modeling,i.e.,catchlike dissociation between integrin and fibronectin,and unfolding of repeated domains in *** probable unfolding of fibronectin domains is found to have profound effects on the resultant adhesion energy of the integrin-fibronectin-mediated interface,and governs the failure model transiting between uniform decay and catastrophic crack-like rupture.

关键词： Integrin-fibronectin complex Cell-matrix adhesion Domain unfolding Catch bond Rate dependence Modulus effect

惠民凹陷江家店地区古近系沙河街组物源体系特征与演化

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沉积学报 2024年第1期42卷 187-200页

作者：柴君林王艳忠王铸坤王淑萍李宇志弭连山周磊中国石油大学(华东)地球科学与技术学院山东青岛266580 中国石油大学(华东)石油工业训练中心山东青岛266580 中国石化胜利油田分公司东辛采油厂山东东营257061 中国石化胜利油田分公司胜利采油厂山东东营257000 中国石化胜利油田分公司勘探开发研究院山东东营257000

【目的】惠民凹陷江家店地区沙四上—沙三段物源体系认识薄弱,增加了砂体和储层预测的难度。系统分析物源体系特征及演化,可为砂体和储层预测奠定基础。【方法】通过特征元素、岩石组分Q型聚类和砂砾岩百分含量分布特征等分析,识别出研... 详细信息

【目的】惠民凹陷江家店地区沙四上—沙三段物源体系认识薄弱,增加了砂体和储层预测的难度。系统分析物源体系特征及演化,可为砂体和储层预测奠定基础。【方法】通过特征元素、岩石组分Q型聚类和砂砾岩百分含量分布特征等分析,识别出研究区物源区和碎屑物质搬运路径,建立了物源体系演化模式。【结果与结论】沙四上—沙三段层序Ⅰ至层序Ⅴ的特征元素比值分布模式与中生界具有良好的吻合关系,表现为明显高Mg/Mn比值、Al/Mg比值和较高Al/Na比值、Ba/Mn比值的特点;岩石组分Q型聚类分析结果表现为五种QFR组合,揭示了三大物源体系,包括过夏27—夏斜98井区物源体系、过夏37井区物源体系、过夏222—夏223—夏225井区物源体系;层序Ⅰ、层序Ⅱ时期,研究区东南侧的鲁西隆起区提供大量的碎屑物质,砂体发育范围大,层序Ⅲ时期物源区明显后退,砂体规模变小,层序Ⅳ、层序Ⅴ时期物源区向湖盆推进,砂体展布范围再次扩大。

关键词：特征元素聚类分析物源体系沙河街组江家店地区惠民凹陷

Investigation in the Effects of Configuration Parameters on the Thermal Behavior of Novel Conical Friction Plate in Continuously Sliding Condition

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Computers, Materials & Continua 2018年第9期56卷 353-363页

作者： yanzhong wang Xiangyu Wu School of Mechanical Engineering Beihang University37 Xueyuan RoadHaidian DistrictBeijing100191China

To investigate the effects of configuration parameters and operation condition on the thermal behavior of novel conical friction plate,a three-dimensional finite element model of conical friction plate is established for numerical *** conical surface configuration and friction heat generation of novel conical friction surfaces are *** results indicate that the thermal behavior of the conical friction plate during continuously sliding period is influenced by the conical surface *** temperature occurs in the conical friction plate with cone angle of 24°.The maximum temperature value of friction plate is increased 7.4°C,when cone depth increases from 3 mm to 4 *** behavior investigation should be carried out when optimize conical surface configuration.

关键词： Transmission wet clutch conical configuration surface configuration thermal behavior

济阳坳陷车西洼陷二叠系上石盒子组致密砂岩储层成岩-成藏系统演化

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中国石油大学学报（自然科学版） 2024年第4期48卷 43-56页

作者：王艳忠宋磊孟涛操应长孙沛沛王淑萍弭连山中国石油大学(华东)地球科学与技术学院山东青岛266580 深层油气全国重点实验室(中国石油大学(华东)) 山东青岛266580 中国石化胜利油田分公司勘探开发研究院山东东营257000 中国石油大学(华东)石油工业训练中心山东青岛266580 中国石化胜利油田分公司胜利采油厂山东东营257000

致密砂岩储层成岩-成藏系统演化决定储层致密化过程和优质储层成因与分布。以车西洼陷上石盒子组致密砂岩储层为例,通过薄片观察、包裹体分析、激光剥蚀电感耦合等离子质谱仪分析等技术,结合埋藏史和构造演化史,对致密砂岩储层的成岩-... 详细信息

致密砂岩储层成岩-成藏系统演化决定储层致密化过程和优质储层成因与分布。以车西洼陷上石盒子组致密砂岩储层为例,通过薄片观察、包裹体分析、激光剥蚀电感耦合等离子质谱仪分析等技术,结合埋藏史和构造演化史,对致密砂岩储层的成岩-成藏系统演化进行系统研究。结果表明:车西洼陷上石盒子组致密砂岩储层硅质胶结物主要为来源于石英颗粒压溶作用的第一期石英次生加大边,长石溶蚀供源的第二期石英次生加大边、充填石英颗粒破裂缝型自生石英以及充填粒间孔隙型自生石英;高岭石分别为原始沉积的充填孔隙细晶高岭石杂基,大气淡水淋滤长石形成的充填孔隙粗晶高岭石,深埋藏封闭环境长石溶蚀原位沉淀形成的颗粒形态高岭石;车西洼陷上石盒子组致密砂岩的成岩-成藏系统演化过程为原始沉积的含细晶高岭石杂基的长石质石英砂岩→充填孔隙粗晶高岭石→黄色荧光油充注→硅质胶结物→天然气→充填孔隙粗晶高岭石→硅质胶结物→蓝色荧光油充注→天然气→颗粒形态高岭石、伊利石、绿泥石。

关键词：成岩-成藏系统演化硅质胶结高岭石致密砂岩上石盒子组车西洼陷

An optimal method of posture adjustment in aircraft fuselage joining assembly with engineering constraints

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Chinese Journal of Aeronautics 2017年第6期30卷 2016-2023页

作者： Yuan LI Li ZHANG yanzhong wang School of Mechanical Engineering and Automation Beihang University

Posture of an aircraft fuselage can be evaluated based on the coordinate values of measure points fixed on the aircraft fuselage in aircraft final assembly. Posture adjustment is carried out by rotation and translation of the aircraft fuselage to make sure that the actual coordinate values of the measure points are coincided with the theoretical ones read from the computer aided design(CAD) model. The point registration method of posture adjustment without considering engineering constraints may cause out-of-tolerance for some engineering constraints. Hence, engineering constraints such as plane symmetry of two points, as well as coplanar and collinear of the multipoint should be considered in the new optimal method of posture adjustment in aircraft fuselage joining assembly. Based on the point registration model, a multi-objective optimization model of posture adjustment considering engineering constraints including collinear, coplanar, and symmetry constraints is established and represented by a uniform vector function. The weights of constraint conditions can be set freely in the optimization model to reflect the importance of the corresponding constraints in aircraft fuselage joining assembly. The rotation and translation parameters of posture adjustment are obtained by the proposed multi-objective optimization algorithm based on the Gauss-Newton method. Results of an example of aircraft fuselage joining assembly show that constraint errors of posture adjustment obtained by the multi-objective optimization model are not out of tolerance for design constraint errors and satisfy the requirement of aircraft fuselage joining assembly.

关键词： Aircraft assembly Engineering constraint Least-squares method Multi-objective optimization Point registration Posture adjustment

RANDOM EVOLVING NETWORKS UNDER THE DIAMETER AND AVERAGE CONNECTIVITY CONSTRAINT

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Journal of Systems Science and Systems Engineering 2007年第1期16卷 107-112页

作者： Jianguo LIU Zhongtuo wang yanzhong DANG Institute of System Engineering Dalian University of Technology Dalian 116023 PR China

In this paper, under the constraint that the average distance and the average degree （k） remain approximately constant, we studied a random scale-free network model. We found that, if the network maintains the form of its degree distribution and the maximal degree kc is N-dependent cutoff function kc（N）〈 N, the degree distribution would be approximately power-law with an exponent between 2 and 3. The distribution exponent has little relationship with the average degree, denoted by （k）. The diameter constraint can be interpreted as an environmental selection pressure, which could explain the scale-free nature of networks. The numerical results indicate that, under the diameter constraint, the preferential attachment can produce the cutoff function kc（N）〈 N and power-law degree distribution.

关键词： Scale-free networks diameter average connectivity

Development of the New Rural Cooperative Medical System in China

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China & World Economy 2007年第4期15卷 66-77页

作者： yanzhong wang Senior Fellow Institute of Sociology Chinese Academy of Social Sciences China. Email: wangyzh@cass.org.en.

Based on a survey conducted by our research team at the Chinese Academy of Social Sciences, the present paper reports on the development of China＇s new rural cooperative medical system set up in late 2002. The new rural cooperative medical system is different from the old system in that it is organized, guided and supported by the government but that rural residents voluntarily participate in its administration. It is financed by individuals, collectives and the government. The new cooperative medical system focuses on serious disease planning and mutual aid and fraternily between rural residents in health care. The results of our survey indicate that the new rural medical system has been successful up to now but that it also has some problems. China needs to pay more attention to overcoming the difficulties and challenges it faces in terms of future medical needs so that a mechanism for its sustainable development can be established.

关键词： health care mutual aid participation rate rural cooperative medical system

Dynamics of buoyancy-driven microflow in a narrow annular space

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第12期24卷 1131-1139页

作者： yanzhong wang Yaping ZHANG Kai YANG Boji LU Hao GAO School of Mechanical Engineering&Automation Beihang UniversityBeijing 100191China Bejing Spacecraft Beijing 100094China School of Mechanical and Electrical Engineering Sanming UniversitySanming 365001China

This paper aims to investigate the dynamics of buoyancy-driven microflow in a narrow annular space inside a liquid floated gyroscope(LFG). Several theoretical models with a non-uniform thermal boundary for fluid flow in annular channels are given to analyze the effects of various parameters, such as the clearance size h, roughness height re, and rough density ε, on the flow and temperature profiles as well as on the fluid-drag torque. In the narrow annular regime, the relationship between the temperature and the angular displacement of the outer wall is defined as a cosine function, and the surface roughness of the inner wall is structured as a series of surface protrusions with a circular shape. With the increase of clearance size h, the flow velocity gradually increases to a stable level, and the drag torque increases initially and then decreases to a stable level. Furthermore, the increase of roughness height re and roughness density ε intensifies the frictional effect of fluid on the inner-wall surface. However, these two parameters have no significant effect on the flow velocity. This study can provide theoretical references for precision manufacturing and precision improvement of gyro instruments.

关键词： Liquid floated gyroscope(LFG) Annular channel Roughness feature Fluid drag