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Analysis elastic-plastic behaviour and anisotropy properties of copper film from nanoindentation using numerical computation method

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MICRO & NANO LETTERS 2011年第1期6卷 13-18页

作者： Han, Xuesong Wang, Shuxin Gan, Yong X. Zhang, Lianhong Yu, Siyuan Tianjin Univ Sch Mech Engn Tianjin 300072 Peoples R China Univ Toledo Coll Engn Toledo OH 43606 USA

The determination of mechanical properties of nanoscale structures is becoming increasingly important as micro-system and ultra-large-scale integrated circuit technologies continue to mature. Traditional experimental methods cannot avoid the influence on the hardness measurement from the presence of the substrate. Numerical computation method of finite-element modelling with molecular dynamics simulation is used to determine the mechanical properties of copper thin film from indentation, quantifying the difference between load against displacement-into-surface curves obtained from different length scale. The results show that the materials deformation exhibits strong size dependence when the relevant physical length scales fall into the range of microns or below. The P-H graph justifies that the permanent plastic deformation quickly decreased while the elastic deformation gradually increased in the range of nanometre level which means increasing of material microhardness. The different deformation behaviour of crystal layers inside the films may be the potential key factor of its breaking off from the substrate. There is little anisotropy phenomenon in the elastic deformation stage whereas there is obvious anisotropy phenomenon in the plastic deformation process. The anisotropy of thin film has strict preferred orientation distribution and symmetry. The anisotropy deformation gradually minimised accompanying the increasing of plastic deformation illuminates the copper thin film is a nonlinear anisotropy elastic-plastic material.

关键词： Deformation and plasticity modelling and computer simulation of solid structure Deformation, plasticity and creep nonlinear anisotropy elastic-plastic material copper nanoindentation Elasticity, elastic constants material microhardness strong size dependence copper thin film metallic thin films Physical properties of thin films, nonelectronic orientation distribution microhardness microsystem integrated circuit technologies finite-element modelling Fatigue, embrittlement, and fracture elastic deformation crystal layers Fatigue, brittleness, fracture, and cracks molecular dynamics simulation hardness measurement plastic deformation P-H graph anisotropy phenomenon deformation behaviour Elasticity and anelasticity anisotropy properties permanent plastic deformation nanoscale structure numerical computation method molecular dynamics method ultralarge-scale integrated circuit technologies Cu finite element analysis elastic-plastic behaviour

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Effect of sol-gel composition ratio and laser power on phase transformation of crystalline titanium dioxide under CO₂ laser annealing

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MICRO & NANO LETTERS 2011年第7期6卷 494-497页

作者： Chung, C. K. Lin, S. L. Cheng, S. Y. Chuang, K. P. Wang, H. Y. Natl Cheng Kung Univ Dept Mech Engn Ctr Micro Nano Sci & Technol Tainan 70101 Taiwan

The crystalline structure of titanium dioxide (TiO2) is very much related to its properties. The sol-gel process and CO2 laser annealing instead of conventional furnace annealing have been performed to investigate the crystalline TiO2 formation. The sol-gel solution was mixed by tetraisopropyl orthotitanate (TTIP), acetonylacetone, distilled water and alcohol at various molar ratios and spin-coated on the p-Si(100) substrate. Then the CO2 laser annealing in air at powers of 0.5, 1.5 and 3.0 Win the defocus mode was performed on the coatings for studying the crystallisation of titanium oxide. The microstructure and phase transformation of titanium dioxide were examined by X-ray diffraction pattern. Increasing TTIP concentration and decreasing laser power were favourable for anatase phase formation. The grain size of titanium dioxide calculated using Scherrer's formula was between 10 and 32 nm, which increased with increasing laser power. The ANSYS simulation was employed to calculate the temperature distribution of films to correlate with the phase transformation of titanium dioxide. This sol-gel processing combined with CO2 laser annealing had advantages of low cost, controllable titanium dioxide phase, selective area annealing and easy operating at room temperature.

关键词： size 10 nm to 32 nm X-ray diffraction pattern titanium compounds Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder modelling and computer simulation of solid structure microstructure furnace annealing power 1.5 W solid-solid transitions crystalline TiO2 formation power 0.5 W film temperature distribution power 3 W sol-gel composition ratio Scherrer formula spin-coating crystallisation Deposition from liquid phases (melts and solutions) crystalline titanium dioxide CO2 gas lasers X-ray diffraction Microstructure ANSYS simulation phase transformation TTIP concentration selective area annealing defocus mode titanium oxide crystallisation CO2 laser annealing Si laser power Annealing processes grain size anatase phase formation laser beam annealing solid-state phase transformations Laser materials processing molecular dynamics method p-Si(100) substrate TiO2 sol-gel processing

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Thermal-stability and compressive properties of one boron nitride nanotube embedded in another carbon tube

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MICRO & NANO LETTERS 2011年第6期6卷 444-447页

作者： Shen Haijun Tongji Univ Sch Aeronaut & Astronaut Shanghai 210016 Peoples R China

The melting and axial compression of one (5, 5) single-walled boron nitride (BN) nanotube, as well as the (5, 5) BN tube embedded in one (10, 10) carbon nanotube, were simulated by molecular dynamics method. According to the calculated results, their differences in thermal-stability and compressive properties were discussed. It is shown that (i) the single-walled BN nanotube melts at about 4600 K, and the BN tube restricted in the carbon tube basically holds its configuration even at the high temperature of 5000 K;(ii) the restricted BN tube has much better anti-compression capability than the single-walled BN nanotube.

关键词： Deformation and plasticity modelling and computer simulation of solid structure Deformation, plasticity and creep axial compression carbon nanotube anticompression capability structure of solid clusters, nanoparticles, nanotubes and nanostructured materials wide band gap semiconductors melting BN compressive strength compressive properties structure of fullerenes and fullerene-related materials single-walled boron nitride nanotube III-V semiconductors boron compounds thermal stability carbon nanotubes C-BN Mechanical and acoustical properties of solid surfaces and interfaces molecular dynamics method

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Temperature-sensitive nanocapsules for methane storage

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MICRO & NANO LETTERS 2009年第3期4卷 172-176页

作者： Suyetin, M. V. Vakhrushev, A. V. Inst Appl Mech Ub RAS Izhevsk 426006 Russia

A nanocapsule is investigated for methane storage purposes. The nanocapsule is a 'bucky shuttle' (or a nanopeapod) with a hole in its structure. The bucky shuttle has a diameter of a nanotube (10, 10) and is 180 A in length. A K@C-60(1+) endohedral complex is encapsulated into the nanocapsule. simulations are performed by a molecular dynamics method. The internal dynamics of the system are investigated - the nanocapsule, the K@C-60(1+) endohedral complex and methane molecules. The closing of the nanocapsule can be induced by the K@C-60(1+) ion transition as a result of applying an electric field. There is no need to keep the electric field at the storage stage, because the K@C-60(1+) ion cannot overcome the hole area owing to the effect of forces created in the hole of the nanocapsule. The opening of the nanocapsule takes place under the heating of the system. It is shown that this is a temperature-sensitive nanocapsule for methane molecule storage under zero external pressure and a temperature of 300 K. The nanocapsule retains 71 methane molecules (3.06 mass%) and releases gas at 350 K.

关键词： modelling and computer simulation of solid structure temperature 300 K nanopeapod temperature-sensitive nanocapsules fullerenes structure of solid clusters, nanoparticles, nanotubes and nanostructured materials adsorption encapsulation structure of fullerenes and fullerene-related materials Sorption and accommodation coefficients (surface chemistry) methane molecules bucky shuttle endohedral complex temperature 350 K ion transition Preparation of fullerenes and fullerene-related materials, intercalation compounds, and diamond methane storage nanostructured materials molecular dynamics method Methods of nanofabrication and processing

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Nested boron nitride and carbon-boron nitride nanocones

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MICRO & NANO LETTERS 2007年第2期2卷 46-49页

作者： Baowan, D. Hill, J. M. Univ Wollongong Sch Math & Appl Stat Nanomech Grp Wollongong NSW 2522 Australia

In this letter we extend previously established results for nested carbon nanocones to both nested boron nitride and carbon-boron nitride nanocones. Based purely on mechanical principles and classical mathematical modelling techniques, we determine the energetically favourable structures for nested boron nitride and carbon-boron nitride nanocones. While only three apex angles for boron nitride tend to occur, we also consider the other two angles corresponding to the equivalent carbon nanocones. Two nanocones are assumed to be located co-axially in a vacuum environment. The Lennard-Jones parameters for boron nitride and carbon-boron nitride systems are calculated using the standard mixing rule. For the boron nitride cones, numerical results indicate that the interspacing between two cones is approximately 3.4 angstrom which is comparable with the experimental results. For the hybrid carbon-boron nitride cones, the numerical results essentially depend on the outer cone angle, and the interspacing distance is also obtained to be approximately 3.4 angstrom. Moreover, the equilibrium position is such that one cone is always inside the other, and therefore nested double-cones are possible in practice.

关键词： modelling and computer simulation of solid structure Lennard-Jones potential structure of solid clusters, nanoparticles, nanotubes and nanostructured materials carbon-boron nitride nanocones BN hardness three apex angle Lennard-Jones parameter III-V semiconductors Fatigue, embrittlement, and fracture CBN nested boron nitride carbon compounds Fatigue, brittleness, fracture, and cracks classical mathematical modelling technique boron compounds interspacing distance nanostructured materials CBN - System BN - Binary mechanical principle

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Orbiting nanosectors inside carbon nanotori

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MICRO & NANO LETTERS 2007年第3期2卷 50-53页

作者： Hilder, T. A. Hill, J. M. Univ Wollongong Sch Math & Stat Nanomech Grp Wollongong NSW 2522 Australia

The notion of nanotransport or nanomotion is presently a theoretical concept only, in that no one has actually observed the phenomena in an experimental context. For example, the oscillatory motion of one carbon nanotube sliding inside another is predicted on the basis of molecular dynamics studies, and the authors have provided some elementary modelling of the phenonmena. More recently, the authors have modelled a C-60 fullerene orbiting inside a nanotori. The related problem of a carbon nanotorus-nanosector oscillator or orbiter is examined, in which a small sector of a nanotorus orbits inside a second seamless nanotorus of larger radius. Using elementary mechanical principles and applied mathematical modelling techniques, we determine the equilibrium configuration for a number of carbon nanotorus-nanosector oscillators and subsequently investigate their operating frequencies. In line with carbon nanotube oscillators, the proposed analysis predicts orbiting frequencies in the gigahertz range.

关键词： nanotransport oscillations C modelling and computer simulation of solid structure carbon nanotubes carbon nanotori fullerenes nanomotion molecular dynamics carbon nanotube molecular dynamics method oscillatory motion nanosectors structure of fullerenes and fullerene-related materials fullerene

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Computing the Szeged index of third and fourth dendrimer nanostars

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MICRO & NANO LETTERS 2007年第4期2卷 107-110页

作者： Iranmanesh, A. Gholami, N. Tarbiat Modares Univ Fac Sci Dept Math Tehran Iran Culture & Res TMU Acad Ctr Educ Tehran Iran

Let e be an edge of a graph, G, connecting the vertices u and v. Define two sets N-1(e vertical bar G) and N-2( e vertical bar G) as N-1( e vertical bar G) {x is an element of V( G)vertical bar d(x, u), d(x, v)} and N-2( e vertical bar G) {x is an element of V(G)vertical bar d(x, v), < d(x, u)}. The number of elements of N-1(e vertical bar G) and N-2(e vertical bar G) are denoted by n(1)(e vertical bar G) and n(2)(e vertical bar G), respectively. The Szeged index of the graph G is defined as Sz(G) = Sigma(e is an element of E(G))n(1)(e vertical bar G) n(2)(e vertical bar G). In this Letter, the Szeged index of third and fourth dendrimer nanostars is computed.

关键词： third dendrimer nanostars modelling and computer simulation of solid structure topology macromolecules nanostructured materials Szeged index topological index structure of solid clusters, nanoparticles, nanotubes and nanostructured materials fourth dendrimer nanostars

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