检索结果-南通市图书馆

Controllable and switchable capillary adhesion mechanism for bio-adhesive pads: Effect of micro patterns

Chinese Science Bulletin 2009年第10期54卷 1648-1654页

作者： ZHANG XiangJun LIU Yuan LIU YongHe AHMED S.I.-U. state Key Laboratory of Tribology Tsinghua University Beijing 100084 China Institute of Physics and center for Micro/Nano Technology Technical University of IImenau PF 100565 Germany

Some insects and animals, such as bugs, grasshoppers and tree frogs, realize their efficient adhesion mechanism to glass surface, wall and ceiling by injecting a wetting liquid thin film into the pad-substrate contact area. Their ability to control adhesion (attaching or detaching from a surface) is in many cases connected to the contact geometry and surface patterns of their attachment pads. This paper focuses on the dependence of the capillary adhesion (wet adhesion) on the micro patterns of the bio-adhesive pads. The objective is to reveal the possible mechanism for a bio-adhesive pad to control capillary force through adjusting its micro-scale surface pattern and topography. A capillary adhesion force model is built up taking account of the combined role of micro-dimple geometry as well as the wetting behavior of the confined liquid thin film. Calculated results of the apparent contact angle on the regularly micro-dimpled surfaces are compared with and in good agreement with the experimental measurements. Simulation of the capillary adhesion force reveals that it is controllable in a large mag- nitude by adjusting a dimensionless surface pattern parameter k defined as a/(a+b), where a is the dia- meter of micro dimple, and (a+b) is the side length of one pattern cell. When adjusting the parameter k more than 0.75, the capillary adhesion force could be switchable from attractive to repulsive. This effect of micro patterns on the interfacial capillary force is proved to be dominant when the pad-substrate clearance decreases to the nano/micrometer scale. These results indicate that a controllable and switchable capillary adhesive mechanism might be utilized by a living insect or animal to realize its stable adhesion and quick releasing movement through adjusting the micro-pattern topography of its bio-adhesive pad.

关键词：毛细管力可能机制粘合剂粘附生物开关可控玻璃表面

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Anisotropic and mutable magnetization in Kondo lattice CeSb2

引用

Chinese Physics B 2017年第6期26卷 319-323页

作者：张云朱燮刚胡丙锋谭世勇谢东华冯卫刘琴张文刘瑜宋海峰罗丽珠张政军赖新春 Science and Technology on Surface Physics and Chemistry Laboratory Department of engineering Physics Tsinghua University Key Laboratory of Neutron Physics Institute of Nuclear Physics and ChemistryChina Academy of Engineering Physics Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Software center for High Performance Numerical Simulation China Academy of Engineering Physics Key Laboratory of Advanced Materials (MOE) School of Materials Science and EngineeringTsinghua University

We have systematically studied the behaviors of the resistivity and magnetization of CeSb2 single crystals as a function of temperature and external field. Four anomalies in the resistivity/magnetization-versus-temperature curves are observed at low magnetic field. They are located at 15.5 K, 11.5 K, 9.5 K, and 6.5 K, corresponding to the paramagnetic–magnetically ordered state（MO）, MO-antiferromagnetic（AFM）, AFM–AFM, and AFM–ferromagnetic（FM） transitions, respectively.The anomaly at 9.5 K is only visible with H‖[010] by magnetic susceptibility measurements, indicating that the AFM–AFM transition only happens along [010] direction in ab-plane. The four magnetic transitions are strongly suppressed by high external field. Finally, the field-temperature phase diagrams of CeSb2 with different orientations of the applied field in ab-plane are constructed and indicate the highly anisotropic nature of the magnetization of CeSb2.

关键词： CeSb2 electronic properties magnetic properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microbial diversity accumulates in a downstream direction in the Three Gorges Reservoir

引用

Journal of Environmental Sciences 2021年第3期33卷 156-167页

作者： Shang Wang Weiguo Hou Hongchen Jiang Liuqin Huang Hailiang Dong Shu Chen Bin Wang Yongcan Chen Binliang Lin Ye Deng CAS Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Environment and Resource Southwest University of Science and TechnologySichuan 621010China state Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesBeijing 100083China School of Ocean Sciences China University of GeosciencesBeijing 100083China state Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China Department of Hydraulic engineering Tsinghua UniversityBeijing 100084China Department of Geology and Environmental Earth Science Miami UniversityOxfordOH 45056USA

Organic and inorganic materials migrate downstream and have important roles in regulating environmental health in the river networks.However,it remains unclear whether and how a mixture of materials(i.e.,microbial species)from various upstream habitats contribute to microbial community coalescence upstream of a dam.Here we track the spatial variation in microbial abundance and diversity in the Three Gorges Reservoir based on quantitative PCR and 16 S rRNA gene high-throughput sequencing data.We further quantitatively assess the relative contributions of microbial species from mainstem,its tributaries,and the surrounding riverbank soils to the area immediately upstream of the Three Gorges Dam(TGD).We found an increase of microbial diversity and the convergent microbial distribution pattern in areas immediately upstream of TGD,suggesting this area become a new confluence for microbial diversity immigrating from upstream.Indeed,the number of shared species increased from upstream to TGD but unique species decreased,indicating immigration of various sources of microbial species overwhelms local environmental conditions in structuring microbial community close to TGD.By quantifying the sources of microbial species close to TGD,we found little contribution from soils as compared to tributaries,especially for sites closer to TGD,suggesting tributary microbes have greater influence on microbial diversity and environmental health in the Three Gorges Reservoir.Collectively,our results suggest that tracking microbial geographic origin and evaluating accumulating effects of microbial diversity shed light on the ecological processes in microbial communities and provide information for regulating aquatic ecological health.

关键词： Three Gorges Dam Microbial source tracking Microbial community coalescence Immigration Accumulating effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An Effective Eigenchannel R-Matrix Method for Calculating Electron-Ion Scattering Processes with Spectroscopic Precision

引用

Chinese Physics Letters 2012年第3期29卷 71-74页

作者：高翔李家明 Beijing Computational Science research center Beijing 100084 Key Laboratory for Laser Plasmas(Ministry of Education)and Department of Physics Shanghai Jiao Tong UniversityShanghai 200240 Department of Physics and center for Atomic and Molecular Nanosciences Tsinghua UniversityBeijing 100084

The electron-ion scattering processes are very important in various scientific research fields such as astrophysical studies and inertial confinement fusion research.We report our recent development of an efficient method for providing such atomic data with spectroscopic precision.Based on the Breit-Pauli and the Dirac R-matrix theory,we develop two eigenchannel R-matrix codes,referred to as R-eigen(non-relelativistic eigenchannel R-matrix)and R-R-eigen(relativistic eigenchannel R-matrix),to directly calculate the physical quantities in multichannel quantum defect theory in the whole energy regions.From such physical quantities,we can obtain all energy levels and the related scattering cross sections with accuracies comparable with spectroscopic precision.The e+Kr+system is used as an illustration example,the degrees of accuracies of scattering matrices are calculated within about 2%,which should be much more accurate than state-of-the-art scattering experiments.

关键词： quantities spectroscopic illustration

来源：

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

Insight of chemical environmental risk and its management from the vinyl chloride accident

引用

Frontiers of Environmental Science & engineering 2023年第4期17卷 167-171页

作者： Bin Wang Liping Heng Qian Sui Zheng Peng Xuezhi Xiao Minghui Zheng Jianxin Hu Heidelore Fiedler DamiàBarceló Gang Yu Beijing Laboratory of Environmental Frontier Technology Beijing Key Laboratory of Emerging Organic Contaminants ControlSchool of EnvironmentTsinghua UniversityBeijing 100084China research Institute for Environmental Innovation(Suzhou) TsinghuaSuzhou 215163China School of Chemistry Beihang UniversityBeijing 100191China School of Resources and Environmental engineering East China University of Science and TechnologyShanghai 200237China Foreign Environmental Cooperation center Ministry of Ecology and Environment of ChinaBeijing 100035China state Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Environmental Sciences and engineering Peking UniversityBeijing 100871China School of Science and Technology MTM Research CentreÖrebro UniversitySE-70182ÖrebroSweden Department of Environmental Chemistry Institute of Environmental Assessment and Water ResearchSpanish Council for Scientific Research(CSIC)Barcelona 08034Spain Advanced Interdisciplinary Institute of Environmental and Ecology Beijing Normal UniversityZhuhai 519000China

The combustion of vinyl chloride(VC)after the train derailment accident in Ohio,USA in February,2023 has caused widespread concern around the world.This paper tried to analyze several issues concerning the accident,including the appropriateness of the VC combustion in the emergency response in this accident,the meanings of so-called“controlled combustion”,the potential environmental risks caused by VC and combustion by-products,and follow-up work.In our view,this accident had surely caused environmental and health risks to some extent.Hence,a comprehensive environmental risk assessment is necessary,and then the site with risk should be comprehensively remediated,hazardous waste should be harmlessly treated as soon as possible.Finally,this accident suggests that further efforts should be taken to bridge the gap between chemical safety management and their environmental risk management.

关键词： Vinyl chloride Combustion Chemical safety management Environmental risk Emerging contaminants

来源：

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

Physical analysis and numerical simulation for the dynamic behaviour of vehicles in pitching oscillations or rocking motions

引用

Science China(Technological Sciences) 2007年第4期50卷 385-401页

作者： ZHANG HanXin1,2,3, ZHANG Zhao1,3, YUAN XianXu1,2, LIU Wei1, XIE YuFei1,2 & YE YouDa1,2 1 China Aerodynamics research and Development center, Mianyang 621000, China 2 National Laboratory for Computational Fluid Dynamics, Beijing university of Aeronautics and Astronautics, Beijing 100083, China 3 School of Aerospace, tsinghua university, Beijing 100084, China China Aerodynamics research and Development center Mianyan China National Laboratory for Computational Fluid Dynamics Beijing University of Aeronautics and Astronautics Beijing China School of Aerospace Tsinghua University Beijing China

Analytical methods of nonlinear dynamics and numerical simulations for the cou-pling equations of Navier-Stokes and flight mechanics are used to study the dynamic behaviour of pitching motions of reentry capsules with the variation of Mach number, and rocking motions of swept wings with the variation of angle of attack. Conditions under which the dynamic instability, Hopf bifurcation and saddle-node bifurcation occur are obtained. The node-saddle-node topological structure in the phase portrait, i.e. the state of bi-attractors (attracting basins) is described. The evolving process of dynamic behaviour and flow fields are given. The theories are compared with some numerical simulations conducted by the authors. Besides, some verifiable experi-mental results are cited. The agreement between them is very well.

关键词： physical analysis numerical simulation pitching oscillation rocking motion bifurcation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Robotic Teleoperation System for Precise Robotic Manipulation by Human-Machine Interaction

引用

上海航天（中英文） 2022年第4期39卷 114-127页

作者： SUN Fuchun GUO Di CHEN Yang Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China

Teleoperation is of great importance in the area of robotics,especially when people are unavailable in the robot workshop.It provides a way for people to control robots remotely using human intelligence.In this paper,a robotic teleoperation system for precise robotic manipulation is established.The data glove and the 7-degrees of freedom(DOFs)force feedback controller are used for the remote control interaction.The control system and the monitor system are designed for the remote precise manipulation.The monitor system contains an image acquisition system and a human-machine interaction module,and aims to simulate and detect the robot running state.Besides,a visual object tracking algorithm is developed to estimate the states of the dynamic system from noisy observations.The established robotic teleoperation systemis applied to a series of experiments,and high-precision results are obtained,showing the effectiveness of the physical system.

关键词： teleoperation human-machine interaction precise manipulation visual object tracking robotich and manipulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

单分子视踪技术揭示SARS-CoV-2病毒利用动态的丝状伪足入侵细胞

引用

科学通报:英文版 2023年第19期68卷 2210-2224,M0004页

作者：张悦张晓玮李钟艺赵唯淞杨慧赵双双汤代骄张倩李总红刘会生李浩宇李博 Pekka Lappalainen 徐涛崔宗强酒亚明 Unit of Cell Biology and Imaging Study of Pathogen Host Interaction The Center for MicrobesDevelopment and HealthKey Laboratory of Molecular Virology and ImmunologyShanghai Institute of Immunity and InfectionChinese Academy of SciencesShanghai 200031China university of Chinese Academy of Sciences Beijing 100049China state Key Laboratory of Virology Wuhan Institute of VirologyCenter for Biosafety Mega-ScienceChinese Academy of SciencesWuhan 430071China Institute of Biomechanics and Medical engineering Applied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua UniversityBeijing 100084China Innovation Photonics and Imaging center School of Instrumentation Science and EngineeringHarbin Institute of TechnologyHarbin 150080China Guangzhou Laboratory Guangzhou 510005China Institute of Biotechnology and Helsinki Institute of Life Science University of HelsinkiHelsinki 00014Finland

SARS-CoV-2病毒侵袭细胞的分子机制已被初步探索,但关于其如何调节亚细胞结构重塑从而侵袭多种器官及细胞类型尚不清楚.本文利用活细胞实时成像技术揭示了SARS-CoV-2病毒颗粒通过宿主细胞丝状伪足进入靶细胞的动态过程.利用荧光标记的SA... 详细信息

SARS-CoV-2病毒侵袭细胞的分子机制已被初步探索,但关于其如何调节亚细胞结构重塑从而侵袭多种器官及细胞类型尚不清楚.本文利用活细胞实时成像技术揭示了SARS-CoV-2病毒颗粒通过宿主细胞丝状伪足进入靶细胞的动态过程.利用荧光标记的SARS-CoV-2病毒样颗粒(VLP)和稀疏去卷积算法成像技术,发现VLP利用丝状伪足以“冲浪”和“抓取”两种模式到达入侵点,以避免病毒在细胞膜上随机搜索入侵位点,此外,结合力学模拟实验,阐明了病毒诱导丝状伪足的形成和丝状伪足的回缩速度分别取决于细胞骨架动力学和病毒重力引起的底物表面摩擦阻力.进一步研究发现SARS-CoV-2通过丝状伪足进入细胞的过程依赖于小G蛋白Cdc42(细胞分裂周期蛋白42)活性和肌动蛋白相关蛋白fasin(肌动蛋白结合蛋白)、formin(成核蛋白)和Arp2/3(肌动蛋白相关蛋白2/3复合物).综上所述,本文结果强调了SARS-CoV-2感染能对宿主细胞的微丝骨架进行时空调节,使细胞形成丝状伪足作为病毒进入的“高速轨道”,丝状伪足形成相关蛋白及其信号通路可作为潜在的抗病毒靶标.

关键词：力学模拟亚细胞结构随机搜索单分子病毒样颗粒表面摩擦阻力病毒侵袭病毒颗粒

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Progress in understanding epigenetic remodeling during induced pluripotency

引用

Science Bulletin 2015年第20期60卷 1713-1721页

作者： Rui Gao Xiaoyu Liu Shaorong Gao Clinical and Translational research center of Shanghai First Maternity and Infant Hospital School of Life Sciences and Technology Tongji University School of Life Sciences Tsinghua University National Institute of Biological Sciences

Over 50 years of efforts, cellular reprogramming opens a new door for disease modeling and regenerative medicine. Although induction of pluripotency by transcription factors has become common, only a small portion of basic mechanisms of epigenetic modifications during this process have been revealed. To clearly understand reprogramming and devise ways to promote full transition towards pluripotency, we must gain insight from comprehensive characterizations of cells at distinct reprogramming stages, which involves gene expression profiling, chromatin state maps of key activating and repressive marks, and DNA modifications. Here, we review recent advances in epigenetic reprogramming to pluripotency with a focus on the principal molecular regulators and attach importance to the combination of high-throughput sequencing and systematic biology approaches in uncovering underlying molecular mechanisms of this unique platform in future researches.

关键词：表观遗传多能性诱导重新编程分子机制 DNA修饰生物学方法再生医学

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ultra-sensitive graphene strain sensor for sound signal acquisition and recognition

引用

Nano research 2015年第5期8卷 1627-1636页

作者： Yan Wang Tingting Yang Junchao Lao Rujing Zhang Yangyang Zhang Miao Zhu Xiao Li Xiaobei Zang Kunlin Wang Wenjian YU Hu Jin Li Wang Hongwei Zhu Department of Physics and Institute for Advanced Study Nanchang University Nanchang 330031 China center for Nano and Micro Mechanics Tsinghua University Beijing 100084 China School of Materials Science and engineering State Key Laboratory of New Ceramics and Fine Processing Key Laboratory ot Materials Processing Technology of MOE Tsinghua University Beijing 100084 China Department of ComputerScience and Technology Tsinghua University Beijing 100084 China 2D Carbon Graphene Material Co. Ltd. Changzhou 213149 China

为健全信号获得和识别的一个便携、高精确的传感器从编织的特殊设计的 graphene 的薄电影被制作织物(GWF ) 。在被拉长之上，随机的裂缝的高密度出现在网络，它减少当前的小径，从而增加电阻。因此，这部电影能对人的喉咙作为一个紧张... 详细信息

为健全信号获得和识别的一个便携、高精确的传感器从编织的特殊设计的 graphene 的薄电影被制作织物(GWF ) 。在被拉长之上，随机的裂缝的高密度出现在网络，它减少当前的小径，从而增加电阻。因此，这部电影能对人的喉咙作为一个紧张传感器起作用以便测量通过肌肉运动，一个声音是否被生产的讲话。超离频敏感允许由提取声波的签名特征的快速、低频率的讲话采样的实现。在这研究， 26 封英语信，典型汉字和音调的代表性的信号，甚至短语和句子被测试，揭示在电阻的明显、典型的变化。而且， graphene 传感器的电阻变化与预告录下的声音完美地反应了。由把人工智能与数字信号处理相结合，我们期望以后，这个 graphene 传感器将能成功地达成复杂声学的系统和听觉的数据的大数量。

关键词：应变传感器声音信号信号采集石墨识别超灵敏数字信号处理英文字母

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：