检索结果-南通市图书馆

Free torsional vibration of cracked nanobeams incorporating surface energy effects

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2017年第2期38卷 217-230页

作者： R. NAZEMNEZHAD P. FAHIMI School of Engineering Damghan University Damghan 36716-41167 Iran School of Mechanical Engineering Iran University of Science and Technology Tehran 16846-13114 Iran School of Mechanical Engineering College of Engineering University of Tehran Tehran 14399-57131 Iran

This paper investigates surface energy effects, including the surface shear modulus, the surface stress, and the surface density, on the free torsional vibration of nanobeams with a circumferential crack and various boundary conditions. To formulate the problem, the surface elasticity theory is used. The cracked nanobeam is modeled by dividing it into two parts connected by a torsional linear spring in which its stiffness is related to the crack severity. Governing equations and corresponding boundary conditions are derived with the aid of Hamilton＇s principle. Then, natural frequencies are obtained analytically, and the influence of the crack severity and position, the surface energy, the boundary conditions, the mode number, and the dimensions of nanobeam on the free torsional vibration of nanobeams is studied in detail. Results of the present study reveal that the surface energy has completely different effects on the free torsionl vibration of cracked nanobeams compared with its effects on the free transverse vibration of cracked nanobeams.

关键词： torsional vibration cracked nanobeam surface energy

Properties of Low surface energy Fluorocarbon Polymers with Fluoro-acrylic Resins

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2008年第3期23卷 285-288页

作者：刘秀生高万振 Wuhan Research Institute of Materials Protection

The low surface energy fluorocarbon polymer from the synthesized fluoro-acrylic resins was developed. Then the molecule orientation principle of nonpolar and polar functional groups in the polymers was analyzed. And the contact angles of pure water drops on the surfaces of various fluoro-monomer homopolymers and interpolymers were measured. So the relation of polymers＇ fluoro-content with the surface energy was determined. The distribution of fluoric functional groups in the polymers was investigated. And the test results show that though the total fluorine content of the fluorocarbon polymers is relative few, their surface energy is really low due to the enrichment of fluoro-chains on the polymers surface.

关键词： contact angle surface energy polymer

TREATMENT OF METALS, POLYMER FILMS, AND FABRICS WITHA ONE ATMOSPHERE UNIFORM GLOW DISCHARGE PLASMA(OAUGDP) FOR INCREASED surface energy AND DIRECTIONAL ETCHING

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2001年第6期14卷 391-407页

作者： J. Reece Roth and Z. Y Chen (Plasma Sciences Laboratory, Department of Electrical and Computer Engineering, University of Tennessee, Knoxville, TN 37996-2100, USA) Peter P.- Y Tsai (Textiles and Nonwovens Development Center (TANDEC), University of Tenness Plasma Sci. Lab. Dept. of Elect. and Comp. Eng. Univ. of Tennessee Knoxville TN 37996-2100 United States

Direct exposure of samples to the active species of air generated by a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) has been used to etch and to increase the surface energy of metallic surfaces, photoresist, polymer films, and nonwoven fab- rics. The OAUGDP is a non-thermal plasma with the classical characteristics of a DC normal glow discharge that operates in air (and other gases) at atmospheric pres- sure. Neither a vacuum system nor batch processing is necessary. A wide range of applications to metals, photoresist, films, fabrics, and polymeric webs can be accom- modated by direct exposure of the workpiece to the plasma in parallel-plate reactors. This technolopy is simple, it produces effects that can be obtained in no other way at one atmosphere; it generates minimal pollutants or unwanted by-products; and it is suitable for individual sample or online treatment of metallic surfaces, wafers, films, and fabrics. Early exposures of solid materials to the OAUGDP required minutes to produce rela- tively small increases of surface energy. These durations appeared too long for com- mercial application to fast-moving webs. Recent improvements in OAUGDP gas com- position, power density, plasma quality, recireulating gas flow, and impedance match- ing of the power supply to the parallel plate plasma reactor have made it possible to raise the surface energy of a variety of polymeric webs (PP, PET PE etc.) to levels of 60 to 70 dynes/cm with one second of exposure. In air plasmas, the high surface ener- gies are not durable, and fall to 50 dynes/cm after periods of weeks to months. Here, we report the exposure of metallic surfaces, photoresist, polymeric films, and nonwo- ven fabrics made of PP and PET to an impedance matched parallel plate OAUGDP for durations ranging from one second to several tens of seconds. Data will be re- ported on the surface energy, wettability, wickability, and aging effect of polymeric films and fabrics as functions of time of exposur

关键词： atmosphere glow discharge plasma surface energy etching of material surface

ATOMISTIC CALCULATIONS OF surface energy OF SPHERICAL COPPER surfaceS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2012年第6期25卷 557-561页

作者： Jianjun Bian Gangfeng Wang Xiqiao Feng SVL Department of Engineering Mechanics Xi’an Jiaotong University Department of Engineering Mechanics Tsinghua University

surface plays an important role in the physical and mechanical behavior of nanos- tructured materials and elements, however surface energy of curved solid surfaces has not been fully understood. In the present letter, surface energy of spherical particles and cavities in FCC copper is calculated by embedded atom method. The numerical simulations reveal that the dis- tribution of atom energy is non-uniform on the curved surfaces. However, when the radius of spherical cavity or particle is larger than 4 nm, the average surface energy density keeps almost constant irrespective of its location and radius.

关键词： surface energy nanoparticle nanocavity

Nanoscale heterogeneous distribution of surface energy at interlayers in organic bulkheterojunction solar cells

在线全文

学校读者我要写书评

暂无评论

Nanoscale heterogeneous distribution of surface energy at in...

Calculation of the surface energy of fcc metals with modified embedded-atom method

第九届新型太阳能材料科学与技术学术研讨会

作者： Yanxun Li Huiqiong Zhou CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology

surface energy of the underneath interlayer plays a crucial role in determining the morphology of bulk-heterojunction(BHJ) film in solution-processed organic solar cells(OSCs). However, little attention has been paid to this perspective at the microscopic level. In this study, we demonstrate an effective strategy to tune the nanoscale heterogeneous distribution of surface energy(HeD-SE) at interlayers through incorporating two-dimensional(2 D) MoS nanosheets, which modulate the component distribution, molecular orientation, and phase separation in the upper BHJ layers, leading to suppressed charge recombination and increased charge extraction in devices with enhanced power conversion efficiency(PCE) and device stability. Furthermore, we explore the relationship among the different surface energies of BHJs between the donor and the acceptor, the nanoscale He D-SE at interlayers, and the PCEs of the resultant devices. This work reveals the impact of nanoscale heterogeneity in the distribution of surface energy in the underneath interlayers on the BHJ morphology and device performanceinOSCs.[1]

关键词： organic solar cells interface surface energy MoS2 morphology

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Physics B 2004年第7期13卷 1082-1090页

作者：张建民马飞徐可为 CollegeofPhysicsandInformationTechnology ShaanxiNormalUniversityXi'an710062China StateKeyLaboratoryforMechanicalBehaviourofMaterials Xi'anJiaotongUniversityXi'an710049China

The surface energies for 38 surfaces of fcc metals Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Rh and Ir have been calculated by using the modified embedded-atom method. The results show that, for Cu, Ag, Ni, Al, Pb and Ir, the average values of the surface energies are very close to the polycrystalline experimental data. For all fcc metals, as predicted, the close-packed (111) surface has the lowest surface energy. The surface energies for the other surfaces increase linearly with increasing angle between the surfaces (hkl) and (111). This can be used to estimate the relative values of the surface energy.

关键词： fcc metals surface energy calculation modified embedded-atom method

Numerical Evaluation of the surface energy of Polyhedral Nanoparticles

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

Materials Sciences and Applications 2020年第12期11卷 837-850页

作者： Takuya Uehara Junya Fujiwara Department of Mechanical Systems Engineering Yamagata University Yonezawa Japan Graduate School of Science and Engineering Yamagata University Yonezawa Japan

Nanoparticles have been used widely in various fields, and their size and shape greatly affect the functional properties. Therefore, controlling the morphology of the particles is important, and evaluation of the surface energy is indispensable for that purpose. In this study, the surface energy of nanoparticles was evaluated by numerical simulation and formulated in a polynomial equation. First, molecular dynamics simulations were carried out for variously shaped polyhedral nanoparticles. A cube and an octahedron were introduced as reference shapes, and truncated hexahedrons and truncated octahedrons were created by cutting out their vertices. The surface energy was plotted for various polyhedrons. The lowest energy was observed in an octahedron because of the stability of the (111) plane, and the highest energy was observed in a cube because of the relatively higher energy of the (100) plane. Then, the surface energy was formulated in a polynomial equation, in which the parameters obtained by the molecular-dynamics simulations were introduced. As a result, stability of the octahedron and relative instability of the cube were fairly captured by the proposed polynomial equation, while a slight underestimation was inevitable. Finally, the parameters were revised to continuous numbers to extend the application range. Consequently, an application for various materials, such as a cube having equivalent stability to an octahedron, was demonstrated by imposing rather exaggerated parameters.

关键词： surface energy Nanoparticle Fcc Crystal Interatomic Potential Molecular Dynamics Computer Simulation

Effect of coupling agent on surface energy of OAT and tensile strength of OAT/EPDM composite

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

Effect of coupling agent on surface energy of OAT and tensil...

Experimental and first-principles calculation of TiN growth mechanism on CeAlO_(3) surface in steel

第八届中国功能材料及其应用学术会议

作者： TANG Qing-guo WANG Fei GUO Hao YANG Yang DU Yu-long LIANG Jin-sheng ZHANG Fuqiang Institute of Power Source & Ecomaterials Science Hebei University of Technology School of chemical engineering Hebei University of Technology

The hydrophilic and character of attapulgite be modified by grafting organic group control surface energy and dispersive interaction for improving compatibility of attapulgite in rubber matrix in order to use attapulgite as rubber *** free energy of could be calculated surface energy of organic modified attapulgite(OAT) and rubber *** surface energies of OAT were measured by several liquids which surface energy and polar interaction,and calculated by Wu’s *** results showed that the dispersive interaction of fillers and the free energy of immersion between fillers and rubber matrix first and then fell with the increase of coupling agent content of coupling agent,tensile strength of rubber composites and dispensability of *** the free energy of immersion reaches the maximum *** above could be used as for of fillers and properties of rubber composites.

关键词： Attapulgite surface modification surface energy Rubber composite Free energy of immersion

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2024年第2期31卷 452-463页

作者： Fei-hu He Jun Peng Fang Zhang Yong-bin Wang Hong-tao Chang School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou014010Inner MongoliaChina

Regular TiN is harmful to the toughness of steel,and its shape and size need to be *** the behavior of TiN precipitation on CeAlO_(3) surfaces is critical for controlling the morphology and formation process of CeAlO_(3)–TiN composite inclusions in the *** results showed that TiN had a square morphology on the CeAlO3 surface,and electron backscatter diffraction phase identification results revealed the orientation relationship between CeAlO_(3) and TiN as follows:(001)_(CeAlO_(3))//(110)_(TiN),(100)_(CeAlO_(3))/(001)_(TiN),and[010]_(CeAlO_(3))/[110]_(TiN).The CeAlO3 crystal structure was studied using the first-principles calculation method,and the adsorption and growth process of TiN on the CeAlO_(3) surface were investigated from the atomic *** calculation results indicate that there is no metallic bonding present in the CeAlO_(3) *** the low-index crystal planes of CeAlO_(3),the(110)planes terminated with O and CeAlO have the highest and lowest surface energies,respectively,with values of 0.373 and 0.051 eV/Å^(2).On the high surface energy plane of CeAlO_(3),the TiN atomic permutation structure is consistent with the arrangement of Ti and N atoms in TiN(100)or(110).For the low surface energy plane of CeAlO_(3),the Ti and N atoms are arranged in a ring-like structure.

关键词： CeAlO_(3)-TiN inclusion Orientation relationship Crystal structure First principle surface energy