检索结果-南通市图书馆

Controllable Nanostructural Transitions in Grafted Nanoparticle-Block Copolymer Composites

在线全文

学校读者我要写书评

暂无评论

Nano Research 2010年第5期3卷 356-362页

作者： Guang-Kui Xu Xi-Qiao Feng Shou-Wen Yu Institute of biomechanics and Medical engineering Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

We report a theoretical investigation of self-assembled nanostructures of polymer-grafted nanoparticles in a block copolymer and explore underlying physical mechanisms by employing the self-consistent field method. By varying the particle concentration or the chain length and density of the grafted polymer, one can not only create various ordered morphologies (e.g., lamellar or hexagonally packed patterns) but also control the positions of nanoparticles either at the copolymer interfaces or in the center of one-block domains. The nanostructural transitions we here report are mainly attributed to the competition between entropy and enthalpy.

关键词： Block copolymer nanocomposite pattern formation self-assembly self-consistent field theory

Molecular Dynamics Simulation on Hydrogen Ion Implantation Process in Smart-Cut Technology

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2016年第2期29卷 111-119页

作者： Bing Wang Bin Gu Hongbin Zhang Xiqiao Feng School of Manufacturing Science and engineering Southwest University of Science and Technology School of Civil engineering and Architecture Hainan University Institute of biomechanics and Medical engineering Department of Engineering MechanicsTsinghua University

The hydrogen ion implantation process in Smart-Cut technology is investigated in the present paper using molecular dynamics（MD） *** work focuses on the effects of the implantation energy,dose of hydrogen ions and implantation temperature on the distribution of hydrogen ions and defect rate induced by ion *** analysis shows that implanted hydrogen ions follow an approximate Gaussian distribution which mainly depends on the implantation energy and is independent of the hydrogen ion dose and implantation *** introducing a new parameter of defect rate,the influence of the processing parameters on defect rate is also quantitatively examined.

关键词： Smart-Cut technology ion implantation molecular dynamics defect rate

Frequency Dispersion of Love Waves in a Piezoelectric Nanofilm Bonded on a Semi-infinite Elastic Substrate

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical engineering 2015年第6期28卷 1157-1162页

作者： ZHANG Sijia GU Bin ZHANG Hongbin PAN Rongying Alamusi FENG Xiqiao School of Manufacturing Science and engineering Southwest University of Science and Technology School of Civil engineering and Architecture Hainan University Institute of biomechanics and Medical engineering Department of Engineering MechanicsTsinghua University

Research on the propagation of elastic waves in piezoelectric nanostructures is very limited. The frequency dispersion of Love waves in layered piezoelectric nanostructures has not yet been reported when surface effects are taken into account. Based on the surface elasticity theory, the propagation of Love waves with surface effects in a structure consisting of a nanosized piezoelectric film and a semi-infinite elastic substrate is investigated focusing on the frequency dispersion curves of different modes. The results show that under the electrically-open conditions, surface effects give rise to the dependence of Love wave dispersion on the film thickness when the thickness of the piezoelectric film reduces to nanometers. For a given wave frequency, phase velocity of Love waves in all dispersion modes exhibit obvious toward shift as the film thickness decreases or the surface parameters increase. Moreover, there may exist a cut-off frequency in the first mode dispersion below which Love waves will be evanescent in the structure due to surface effects. The cut-off frequency depends on the film thickness, the surface parameters and the bulk material properties.

关键词： surface effects electrically-open frequency dispersion love wave piezoelectric nanofilm

Rotating Surfaces Promote the Shedding of Droplets

在线全文

学校读者我要写书评

暂无评论

Research 2023年第1期6卷 583-592页

作者： Ran Tao Wei Fang Jun Wu Binhong Dou Wanghuai Xu Zhanying Zheng Bing Li Zuankai Wang Xiqiao Feng Chonglei Hao School of Mechanical engineering and Automation Harbin Institute of TechnologyShenzhen 518055China Institute of biomechanics and Medical engineering Applied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua UniversityBeijing 100084China Department of Mechanical engineering City University of Hong KongHong Kong 999077China

Achieving rapid shedding of droplets from solid surfaces has received substantial attention because of its diverse *** studies have focused on minimizing contact times of liquid droplets interacting with stationary surfaces,yet little consideration has been given to that of moving ***,we report a different scenario:A water droplet rapidly detaches from micro/nanotextured rotating surfaces in an intriguing doughnut shape,contributing to about 40%contact time reduction compared with that on stationary *** doughnut-shaped bouncing droplet fragments into satellites and spontaneously scatters,thus avoiding further collision with the *** particular,the contact time is highly dependent on impact velocities of droplets,beyond previous descriptions of classical inertialcapillary scaling *** results not only deepen the fundamental understanding of droplet dynamics on moving surfaces but also suggest a synergistic mechanism to actively regulate the contact time by coupling the kinematics of droplet impingement and surface rotation.

关键词： stationary rotating synergistic

STUDY OF THE CLOSING MECHANISM OF NATURAL HEART VALVES

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 1986年第10期7卷 955-964页

作者：雷明康振黄 Research laboratory of biomechanics. Department of engineering Mechanics. Chengdu University of Science and Technology. Chengdu

At present, there are still some controversial considerations on the closing mechanismof natural heart valves. In this area. a lot of phenomena still remain *** the mechanism of earlier partial closure of the valve white the blood ejection is still in itsacceleration phase. It is the purpose of this study to focus on the problem of earlier closuremechanism of heart valves by using both theoretical analysis and experimentalverifications. A certain two-dimensional mathematical model of closure with allcontributing factors and the whole operating process being considered is investigated with anew analytical method Several new conclusions were found. The main points are asfollows:I. During the opening phase, the main factor of motion of the valve is the acceleratingflow, and the decelerating flow plays a main role during most the of time of the decelerationphase. But during the quasi-steady phase of blood ejection. it is the vortex in the sinus thatcontrols the valve closure.2. For Ih

关键词： STUDY OF THE CLOSING MECHANISM OF NATURAL HEART VALVES

Multi-objective Optimal Design of High Frequency Probe for Scanning Ion Conductance Microscopy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical engineering 2016年第1期29卷 195-203页

作者： GUO Renfei ZHUANG Jian MA Li LI Fei YU Dehong School of Mechanical engineering Xi’an Jiaotong University School of Science Xi’an Jiaotong University Bioinspired engineering and biomechanics Center(BEBC) Xi’an Jiaotong University

Scanning ion conductance microscopy（SICM） is an emerging non-destructive surface topography characterization apparatus with nanoscale resolution. However, the low regulating frequency of probe in most existing modulated current based SICM systems increases the system noise, and has difficulty in imaging sample surface with steep height changes. In order to enable SICM to have the capability of imaging surfaces with steep height changes, a novel probe that can be used in the modulated current based bopping mode is designed. The design relies on two piezoelectric ceramics with different travels to separate position adjustment and probe frequency regulation in the Z direction. To fiarther improve the resonant frequency of the probe, the material and the key dimensions for each component of the probe are optimized based on the multi-objective optimization method and the finite element analysis. The optimal design has a resonant frequency of above 10 kHz. To validate the rationality of the designed probe, microstructured grating samples are imaged using the homebuilt modulated current based SICM system. The experimental results indicate that the designed high frequency probe can effectively reduce the spike noise by 26% in the average number of spike noise. The proposed design provides a feasible solution for improving the imaging quality of the existing SICM systems which normally use ordinary probes with relatively low regulating frequency.

关键词： scanning ion conductance microscopy(SICM) multi-objective optimization high frequency probe finite element analysis,imaging quality

Using scores of amino acid topological descriptors for quantitative sequence-mobility modeling of peptides based on support vector machine

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2006年第22期51卷 2700-2705页

作者： LIANG Guizhao YANG Shanbin ZHOU Yuan ZHOU Peng LI Zhiliang Key laboratory for biomechanics and Tissue engineering of Ministry of Education Chongqing 400030 China College of Chemistry and Chemical engineering Chongqing University Chongqing 400030 China State Key laboratory of Chemo/Biosensing and Chemometrics Hunan University Changsha 410082 China

拓扑的描述符(SATD ) 从与 23 氨基酸有关的 1262 个结构的变量的一个矩阵的原则部件分析导出的氨基酸的分数被采用在不同长度表示 125 肽的结构。量的 sequence-mobilitymodelings (QSMM ) 用部分最少的平方被构造(请) 并且支持向量机... 详细信息

拓扑的描述符(SATD ) 从与 23 氨基酸有关的 1262 个结构的变量的一个矩阵的原则部件分析导出的氨基酸的分数被采用在不同长度表示 125 肽的结构。量的 sequence-mobilitymodelings (QSMM ) 用部分最少的平方被构造(请) 并且支持向量机器(SVM ) 分别地。作为新氨基酸规模，包括与生物活性有关的丰富的信息的 SATD 容易被操作。更好的结果与获得与的那些相比被获得请，它显示 SVM 介绍了柔韧的稳定性和优秀预兆的能力 forelectrophoretic 活动性。这些结果证明在 QSMM 为应用 ofSATD 和 SVM 回归有宽前景。

关键词：氨基酸 SATD 电泳迁移率 QSMM SVM

Soft substrate and decreased cytoskeleton contractility promote coupling and morphology maintenance of pluripotent stem cells

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2021年第10期37卷 1520-1529,I0002页

作者： Meihong Lu Jialing Cao Yuanyuan Zhai Peng Zhao Jie Yao Yan Gong Jing Du Yubo Fan Key laboratory for biomechanics and Mechanobiology of the Ministry of Education Institute of Nanotechnology for Single Cell AnalysisBeijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China Institute of biomechanics and Medical engineering Department of Mechanical EngineeringSchool of AerospaceTsinghua UniversityBeijing100084China Sino-French Engineer School Beihang UniversityBeijing100083China School of Material Science&engineering Beijing Institute of Fashion TechnologyBeijing100029China

The mechanical microenvironment affects the morphology and mechanical properties of cells, and it also plays an important role in cell functions. Pluripotent stem cells (PSCs) grow as multicellular colonies, and the coupling effects of cell–cell and cell-extracellular matrix interactions are complex but necessary for the formations and functions of tissues. This paper uses the finite element method to establish a three-dimensional calculation model of a pair of deformed PSCs in contact with each other and considers the growth and depolymerization of actin filaments. Then the effects of substrate stiffness on the morphology of cells and nuclei and the rearrangement of cytoskeleton are demonstrated. As the substrate becomes softer, the nuclei become loose and round, and the actin filaments will be assembled at a lower level, which could promote the formation of compacted cell colony while having a positive effect on maintaining pluripotency and inducing reprogramming efficiency. In addition, stronger activation of cytoskeleton contractility will compress the cytoplasm and nuclei. The cell mechanics model proposed in this paper provides a strategy for studying the cell morphology and cytoskeleton response of the two-cell system under different biophysical stimuli, and also lays the foundation for the further research on more mechanical factors of cell pluripotency.

关键词： Pluripotent stem cells Morphology Cell model Mechanical stimuli

Arg-Gly-Asp(RGD)Modified Biomimetic Polymeric Materials

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2005年第4期21卷 571-576页

作者： Xufeng NIU, Yuanliang WANG Yanfeng LUO Juan XIN Yonggang LI Key Lab of biomechanics & Tissue engineering Ministry of Education Bioengineering College Chongqing University Chongqing400044 China

The new generation of biomaterials focuses on the design of biomimetic polymeric materials that are capable of eliciting specific cellular responses and directing new tissue formation. Since Arg-Gly-Asp （RGD） sequences have been found to promote cell adhesion in 1984, numerous polymers have been functionalized with RGD peptides for tissue engineering applications. This review gave the advance in RGD modified biomimetic polymeric materials,focusing on the mechanism of RGD, the surface and bulk modification of polymer with RGD peptides and the evaluation in vitro and in vivo of the modified biomimetic materials.

关键词： Arg-Gly-Asp (RGD) Biomimetic materials Polymer