Narrow Results

Simulations at T/Tc = 1/4 agree with classical nucleation theory if the droplets are assumed as small cubes instead of spheres.

This paper investigates the size-dependent nonlinear bending of functionally graded carbon nanotube-reinforced (FG-CNTR) nanobeams. Chen–Yao’s surface elasticity and modified couple stress theories are adopted to describe surface effects and couple stress effects, respectively. These nanobeams, in which the carbon nanotube (CNT)-reinforced phases are assumed to be distributed in a gradient along the thickness, are subjected to a uniform pressure and rest on a nonlinear elastic foundation. In accordance with the Euler–Lagrange variational principle, the governing equations and boundary conditions for the FG-CNTR nanobeams, which involve geometric nonlinearity due to the von Kármán strain relations, are obtained. Then, with the assistance of the two-step perturbation technique, the load-deflection relationship is determined for nanobeams subjected to simply supported (SS) and clamped–clamped (CC) boundary conditions. Finally, the impacts of various factors, including surface properties, characteristic material length, elastic foundation, geometric factors, layout type and volume fraction of CNTs, on the mechanical behaviors of CNT-based nanobeams are examined. The numerical results reveal that the combination of surface effects and couple stress helps to enhanceq the stiffness of the nanobeams. Furthermore, the size-dependent nonlinear bending of the FG-CNTR nanobeam is markedly affected by the content and layout type of the reinforcements.

A general equation for surface stress is established based on a thermodynamic consideration of the size dependence of solid–liquid interface energy under an assumption that the solid–liquid interface of a particle immersed in surrounding liquid disappears when almost all atoms of the particle are located on its surface. The predicted surface stresses of semiconductors in terms of the model are in agreement with the first principles calculations and calculations based on forces associated with the elastic distortion of the covalent bonds.

In this investigation, the nonlinear flexural free vibration characteristics of size dependent curved isotropic nano/microbeams are studied using the nonlocal elasticity theory along with the sinusoidal shear deformation theory (SSDT). Based on Hamilton’s principle, the governing equations are derived in terms of generalized displacements using finite element approach. The formulation by extending the von-Karman model accounts for both large deflections and rotations in the strain displacement definition. Direct iterative procedure is used to solve the nonlinear problem through eigenvalue procedure. This investigation aims to study the effect of various design parameters like slenderness ratio of the beam, curved beam included angle, nonlocal parameter, and boundary conditions on the amplitude–frequency response obtained from the free vibration behavior of curved nano/microbeams. This study is very useful to designers for optimal design of nano/microsystem involving structural elements of the beam type.

Dissolution of nanoparticles is involved in the preparation, research and application of nanomaterials, but there is a surprising difference in dissolution thermodynamics between nanoparticles and the corresponding bulk materials. In the paper, the relations of dissolution thermodynamic properties, equilibrium constant of nanoparticles, respectively, and particle size were derived by introducing interface variables and the surface chemical potential. Experimentally, the solubility of nano-barium sulfate with different average particle sizes at different temperatures were determined by the method of electrical conductivity, obtaining the influencing regularities of particle size on the dissolution thermodynamic properties and the equilibrium constant. The regularities are in accordance with the theory. The results show that there are remarkable effects of particle size of nanoparticles on the dissolution thermodynamic properties and the equilibrium constant; with the decreasing of the size of nanoparticles, the dissolution equilibrium constant increases, while the standard dissolution Gibbs free energy, the standard dissolution enthalpy and the standard dissolution entropy decrease; and the logarithm of the dissolution equilibrium constant, the standard dissolution Gibbs free energy, the standard dissolution enthalpy and the standard dissolution entropy are linearly associated with the reciprocal of particle size, respectively. This new theory provides a quantitative description of nanoparticles dissolution behavior, and has important scientific significance for understanding and predicting of thermodynamic regularity of dissolution concerned in the preparation, researches and applications of nanomaterials.