• Advances in nano research
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• v.14 no.5
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• pp.475-493
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• 2023

In the context of nonclassical nonlocal strain gradient elasticity, this article studies the free and forced responses of functionally graded material (FGM) porous nanoplates exposed to thermal and magnetic fields under a moving load. The developed mathematical model includes shear deformation, size-scale, miscorstructure influences in the framework of higher order shear deformation theory (HSDT) and nonlocal strain gradient theory (NSGT), respectively. To explore the porosity effect, the study considers four different porosity models across the thickness: uniform, symmetrical, asymmetric bottom, and asymmetric top distributions. The system of quations of motion of the FGM porous nanoplate, including the effects of thermal load, Lorentz force, due to the magnetic field and moving load, are derived using the Hamilton's principle, and then solved analytically by employing the Navier method. For the free and forced responses of the nanoplate, the effects of nonlocal elasticity, strain gradient elasticity, temperature rise, magnetic field intensity, porosity volume fraction, and porosity distribution are analyzed. It is found that the forced vibrations of FGM porous nanoplates under thermal and live loads can be damped by applying a directed magnetic field.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2514-2516
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• 2007

• Structural Engineering and Mechanics
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• v.60 no.4
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• pp.707-727
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• 2016

In this paper, thermal vibration of a nonlocal functionally graded (FG) plates with arbitrary boundary conditions under linear and non-linear temperature fields is explored by developing a refined shear deformation plate theory with an inverse cotangential function in which shear deformation effect was involved without the need for shear correction factors. The material properties of FG nanoplate are considered to be temperature-dependent and graded in the thickness direction according to the Mori-Tanaka model. On the basis of non-classical higher order plate model and Eringen's nonlocal elasticity theory, the small size influence was captured. Numerical examples show the importance of non-uniform thermal loadings, boundary conditions, gradient index, nonlocal parameter and aspect and side-to-thickness ratio on vibrational responses of size-dependent FG nanoplates.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.3 s.246
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• pp.328-333
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• 2006

Movable nanometer-scale structures are fabricated by selective etching of single crystalline Au nanoplates. The nanostructures have arbitrary shapes like gear and alphabet 'A' with in-plane size less than 500 m and thickness of $25\sim60nm$. They could be moved successfully on the substrate using a nanornanipulator installed in a focused ion beam system. Our approach is expected to be useful in fabricating various kinds of nanocomponents which can play a role as building blocks for the sophisticated nanodevices or micromachines.

• Korean Journal of Materials Research
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• v.26 no.1
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• pp.1-7
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• 2016

The graphene oxides (GOs) were tested as a fluorescent quencher in the field of DNA-diagnostics. The various suspensions of GO nanoplates were prepared by changing the synthesis conditions. The suspensions were stable for at least 6 weeks by differing degrees of functionalization of various oxygen-containing groups of atoms. Depending on the properties of GO nanoplates, their fluorescent quenching abilities, which were determined by the amount of the tagged immobilized oligonucleotide, were also changed. GO suspension synthesized at $75^{\circ}C$ of reaction mixture showed the fluorescent quenching of 16.39 nmol/mg, which would be a potential substitution of molecular fluorescent quencher in test-systems for DNA-diagnostics.

• Applied Science and Convergence Technology
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• v.25 no.6
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• pp.149-153
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• 2016

Thermal oxidation has significant potential for use in synthesizing metal-oxide nanostructures from metallic materials. However, this method has limited applicability to the synthesis of multi-morphology NiO from Ni foil. Techniques consisting of mechanical and chemical approaches were used to pre-treat the Ni foil (prior to oxidation) to promote the formation of nanowires and nanoplates on the NiO layer. These morphologies were realized on the Ni foils scratched by sand paper and a knife, respectively, and subsequently heat-treated at $500^{\circ}C$ for 24 h. Small nanowires (diameter: <10 nm) formed on the Ni foil treated by absolute $HNO_3$ and then oxidized at $500^{\circ}C$ for 24 h. The formation of various morphologies (on the pre-treated Ni foil), which differ from that formed in the case of pristine Ni foil after oxidation, may be attributed to the surface melting phenomenon that occurs during the nucleation process.

• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.257-269
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• 2019

This paper develops a nonlocal strain gradient plate model for damping vibration analysis of smart magneto-electro-viscoelastic nanoplates resting on visco-Pasternak medium. For more accurate analysis of nanoplate, the proposed theory contains two scale parameters related to the nonlocal and strain gradient effects. Viscoelastic effect which is neglected in all previous papers on magneto-electro-viscoelastic nanoplates is considered based on Kelvin-Voigt model. Governing equations of a nonlocal strain gradient smart nanoplate on viscoelastic substrate are derived via Hamilton's principle. Galerkin's method is implemented to solve the governing equations. Effects of different factors such as viscoelasticity, nonlocal parameter, length scale parameter, applied voltage and magnetic potential on damping vibration characteristics of a nanoplate are studied.

• Structural Engineering and Mechanics
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• v.69 no.5
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• pp.487-497
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• 2019

Rapid advances in the engineering applications can bring further areas to provide the opportunity to manipulate anisotropic structures for direct productivity in design of micro/nano-structures. For the first time, magnetic affected wave characteristics of nanosize plates made of anisotropic material is investigated via the three-dimensional bi-Helmholtz nonlocal strain gradient theory. Three small scale parameters are used to predict the size-dependent behavior of the nanoplates more accurately. After owing governing equations of wave motion, an analytical approach based harmonic series is utilized to fine the wave frequency as well as phase velocity. It is observed that the small scale parameters, magnetic field and wave number have considerable influence on the wave characteristics of anisotropic nanoplates. Due to the lack of any study on the mechanics of three-dimensional bi-Helmholtz gradient plates made of anisotropic materials, it is hoped that the present exact model may be used as a benchmark for future works of such nanostructures.

• Structural Engineering and Mechanics
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• v.78 no.4
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• pp.379-386
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• 2021

A numerical and computer simulation for dynamic stability analysis of graded porous nanoplates has been provided using a Chebyshev-Ritz-Bolotin approach. The nanoplate has been formulated according to the nonlocal elasticity and a 3-unkown plate model capturing neutral surface location. All of material properties are assumed to be dependent of porosity factor which determines the amount or volume of pores. The nano-size plate has also been assumed to be under temperature and moisture variation. It will be shown that stability boundaries of the nanoplate are dependent on static and dynamical load factors, porosity factor, temperature variation and nonlocal parameter.

• Steel and Composite Structures
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• v.48 no.6
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• pp.709-725
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• 2023

This paper uses a new type of deformation theory to establish the free vibration and static buckling equations of nanoplates resting on two-parameter elastic foundations, in which the flexoelectric effect is taken into account. The proposed approach used in this work is not only simpler than other higher-order shear deformation theories but also does not need any shear correction coefficients to describe exactly the mechanical responses of structures. The reliability of the theory is verified by comparing the numerical results of this work with those of analytical solutions. The results show that the flexoelectric effect significantly changes the natural frequency and the critical buckling load of the nanoplate compared with the case of neglecting this effect, especially when the plate thickness changes and with some different boundary conditions. These are new results that have not been mentioned in any publications but are meaningful in engineering practice.