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Vincent Ji

Bio: Vincent Ji is an academic researcher from Université Paris-Saclay. The author has contributed to research in topics: Residual stress & Shot peening. The author has an hindex of 34, co-authored 276 publications receiving 4069 citations. Previous affiliations of Vincent Ji include Arts et Métiers ParisTech & University of Paris.


Papers
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TL;DR: In this paper, the sensitivity of pristine graphene (PG) and Pd-doped graphene (Pd-G) toward a series of small gas molecules (CO, NH 3, O 2 and NO 2 ) has been investigated by first-principles based on density functional theory.

197 citations

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TL;DR: In this article, the most stable adsorption geometry, adaption energy, magnetic moment, charge transfer, and density of states of these systems are thoroughly discussed using first-principles approach based on density functional theory.

165 citations

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TL;DR: In this paper, a general compliance transformation relation is given for hexagonal crystals and useful expressions of the Young's modulus, Poisson's ratio υ ( h k l ) and X-ray elastic constants (XREC) are also given in terms of the Miller indices of the lattice plane in the crystal axes ( X, Y, Z ) used commonly.

146 citations

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TL;DR: In this article, the residual stress distribution induced by laser shock processing in a 2050-T8 aeronautical aluminium alloy with both X-ray diffraction measurements and 3D finite element simulation is investigated.

115 citations

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TL;DR: In this paper, an Al-Zn-Mg-Cu matrix composite reinforced with uniformly distributed TiB2 nanoparticles was successfully produced and the solid-soluted, peak-aged and overaged materials were then characterized, at the atomic scale using (high-resolution) scanning transmission electron microscopy, to provide a fundamental insight into the interface precipitation.

95 citations


Cited by
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TL;DR: In this paper, the authors used the Williamson-Hall analysis and size-strain plot method to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of ZnO-NPs.

1,784 citations

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TL;DR: In this paper, the root mean square strain was determined from the interplanar spacing and strain estimated from the three models, viz, uniform deformation model, unweighted deformation stress model, and uniform density model.
Abstract: ZnO nanoparticles were prepared by coprecipitation method at 450C. X-ray diffraction result indicates that the sample is having a crystalline wurtzite phase. Transmission electron microscopy (TEM) result reveals that the ZnO sample is spherical in shape with an average grain size of about 50nm. X-ray peak broadening analysis was used to evaluate the crystalline sizes and lattice strain by the Williamson-Hall (W-H) analysis. All other relevant physical parameters such as strain, stress, and energy density values were also calculated using W-H analysis with different models, viz, uniform deformation model, uniform deformation stress model and uniform deformation energy density model. The root mean square strain was determined from the interplanar spacing and strain estimated from the three models. The three models yield different strain values; it may be due to the anisotropic nature of the material. The mean particle size of ZnO nanoparticles estimated from TEM analysis, Scherrers formula and W-H analysis is highly intercorrelated.

1,439 citations

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TL;DR: In this paper, the authors address the nature of these height fluctuations by means of straightforward atomistic Monte Carlo simulations based on a very accurate many-body interatomic potential for carbon and find that ripples spontaneously appear due to thermal fluctuations with a size distribution peaked around 70 \AA which is compatible with experimental findings (50-100 \AA) but not with the current understanding of flexible membranes.
Abstract: The stability of two-dimensional (2D) layers and membranes is subject of a long standing theoretical debate. According to the so called Mermin-Wagner theorem, long wavelength fluctuations destroy the long-range order for 2D crystals. Similarly, 2D membranes embedded in a 3D space have a tendency to be crumpled. These dangerous fluctuations can, however, be suppressed by anharmonic coupling between bending and stretching modes making that a two-dimensional membrane can exist but should present strong height fluctuations. The discovery of graphene, the first truly 2D crystal and the recent experimental observation of ripples in freely hanging graphene makes these issues especially important. Beside the academic interest, understanding the mechanisms of stability of graphene is crucial for understanding electronic transport in this material that is attracting so much interest for its unusual Dirac spectrum and electronic properties. Here we address the nature of these height fluctuations by means of straightforward atomistic Monte Carlo simulations based on a very accurate many-body interatomic potential for carbon. We find that ripples spontaneously appear due to thermal fluctuations with a size distribution peaked around 70 \AA which is compatible with experimental findings (50-100 \AA) but not with the current understanding of stability of flexible membranes. This unexpected result seems to be due to the multiplicity of chemical bonding in carbon.

1,367 citations

01 Jan 1987

991 citations