scholarly journals Фазовая диаграмма состояния и межфазные характеристики в бинарной наносистеме

2018 ◽  
Vol 60 (1) ◽  
pp. 180
Author(s):  
М.А. Шебзухова ◽  
А.А. Шебзухов
Keyword(s):  
Interfacial Tension ◽  
Size Effects ◽  
Interfacial Layer ◽  
Phase State ◽  
Calculated Data ◽  
Size Composition ◽  
Size Dependent ◽  
State Diagrams ◽  
Monodispersed Particles ◽  
The Matrix

AbstractThe size effects on the composition of coexisting phases, the interfacial layer between them, and the interfacial tension in a binary system composed of a matrix and the monodispersed particles of arbitrary (including nanoscale) size are described in the context of a Gibbs method for dispersed systems. Obtaining the relevant relationships has allowed plotting the size-dependent phase state diagrams for a Cr–Ti system with a point of equal concentrations with a minimum. The coefficients of size composition of the nanoparticles and the matrix, as well as those of interfacial tension under the isobaric and isothermal conditions, are calculated at different degree of dispersion. The calculated data coincide with the experimental ones.

scholarly journals Phase Equilibrium and Interdiffusion in Blends of Polystyrene with Polyacrylates

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2283
Author(s):  
Uliana V. Nikulova ◽  
Anatoly E. Chalykh
Keyword(s):  
Diffusion Coefficients ◽  
Phase State ◽  
Pair Interaction ◽  
Side Chain ◽  
Matrix Structure ◽  
State Diagrams ◽  
The Matrix ◽  
Temperature Dependences ◽  
Interferometry Method ◽  
Interdiffusion Coefficients

The solubility and interdiffusion of polystyrene (PS) with polymethyl acrylate (PMA), polyethyl acrylate (PEA), polybutyl acrylate (PBA), and polyethylhexyl acrylate (PEHA) have been studied by the optical interferometry method. Phase state diagrams are plotted. It is shown that they are characterized by the upper critical solution temperatures (UCST), which are localized in the temperature range above 450 K. Pair interaction parameters and their temperature dependences are determined and analyzed. Extrapolation of the temperature dependence of the interaction parameter was used to construct the dome of binodal curves and determine the spinodal curves in the framework of the Flory–Huggins theory. The diffusion coefficients of polystyrene into polyacrylates and polyacrylates into polystyrene are calculated. The dependences of the interdiffusion coefficients on the concentration, temperature, polystyrene molecular weight, and the number of carbons in the side chain of polyacrylate are analyzed. The numerical values of the interdiffusion coefficients of PS-1 into polyacrylates at 433 K change as −8.5 → −6.7 → −6.4 in the homologous series PMA → PEA → PBA. The coefficients of friction are calculated and the effect of change in the matrix structure on the diffusion of polystyrene in them is estimated.

Cosserat Modeling of Size Effects in Crystalline Solids

2000 ◽  
Vol 653 ◽  
Author(s):  
Samuel Forest
Keyword(s):  
Stress State ◽  
Size Effects ◽  
Elastic Inclusion ◽  
Characteristic Size ◽  
Infinite Matrix ◽  
Crystalline Solids ◽  
Generalized Continua ◽  
Absolute Size ◽  
Kink Bands ◽  
The Matrix

AbstractThe mechanics of generalized continua provides an efficient way of introducing intrinsic length scales into continuum models of materials. A Cosserat framework is presented here to descrine the mechanical behavior of crystalline solids. The first application deals with the problem of the stress field at a crak tip in Cosserat single crystals. It is shown that the strain localization patterns developping at the crack tip differ from the classical picture : the Cosserat continuum acts as a bifurcation mode selector, whereby kink bands arising in the classical framework disappear in generalized single crystal plasticity. The problem of a Cosserat elastic inclusion embedded in an infinite matrix is then considered to show that the stress state inside the inclusion depends on its absolute size lc. Two saturation regimes are observed : when the size R of the inclusion is much larger than a characteristic size of the medium, the classical Eshelby solution is recovered. When R is much small than the inclusion, a much higher stress is reached (for an inclusion stiffer than the matrix) that does not depend on the size any more. There is a transition regime for which the stress state is not homogeneous inside the inclusion. Similar regimes are obtained in the study of grain size effects in polycrystalline aggregates of Cosserat grains.

Nucleation & Growth of Precipitates in Transformations Driven by Diffusion

1997 ◽  
Vol 481 ◽  
Author(s):  
N. Clavaguera ◽  
M.T. Clavaguera-Mora
Keyword(s):  
Free Energy ◽  
Calculated Data ◽  
Energy Difference ◽  
Calphad Approach ◽  
Free Energies ◽  
Free Energy Difference ◽  
Diffusion Controlled ◽  
The Matrix ◽  
Rapidly Solidified ◽  
Selection Of

ABSTRACTA theoretical analysis of the transformation kinetics which accounts for nuclei, either prequenched or created homogeneously, and whose growth are controlled by diffusion is presented. The change in growth habit intervening during the transformation is analysed in terms of the evolution of the free energy difference between the precipitate and the matrix at the interface, ΔG1. In the Avrami formalism, this quantity accounts for the competition between interface and diffusion controlled growth whereas the nucleation events are driven by the free energy difference between the precipitate and the bulk matrix. Competition and selection of precipitate phases in highly undercooled melts using the CALPHAD approach for the evaluation of the free energies and the changes in diffusivity with concentration are analysed. Experimental vs. calculated data are discussed in some rapidly solidified metallic systems.

Particle Size Effects in Geological Analyses by X-Ray Fluorescence

1985 ◽  
Vol 29 ◽  
pp. 587-592
Author(s):  
K.K. Nielson ◽  
V.C. Rogers
Keyword(s):  
Particle Size ◽  
Quantitative Analysis ◽  
Size Effects ◽  
Light Element ◽  
New Method ◽  
X Ray ◽  
Particle Size Effects ◽  
Sample Matrix ◽  
Xrf Analysis ◽  
The Matrix

Particle-size effects can cause significant errors in x-ray fluorescence (XRF) analysis of particulate materials. The effects are usually removed when samples are fused or dissolved to standardize the matrix for quantitative analysis. Recent improvements in numerical matrix corrections reduce the need to standardize the sample matrix via fusion or dissolution, particularly when the CEMAS method is used to estimate unmeasured light-element components of undefined materials for matrix calculations. A new method to correct for particle-size effects has therefore been examined to potentially avoid the need for destructive preparation of homogeneous samples.

Phase State Diagrams of a Four-Component System Al-Si-N-O - Analysis of the Thermodynamic Stability of Sialon Compounds Dased on Energy Crystal-Chemistry

2020 ◽  
Vol 303 ◽  
pp. 97-103
Author(s):  
V.A. Vlasov ◽  
Anatoliy A. Klopotov ◽  
V.I. Vereshchagin ◽  
O.G. Volokitin ◽  
K.A. Bezukhov ◽  
...  
Keyword(s):  
Crystal Chemistry ◽  
Crystalline Structure ◽  
Thermodynamic Stability ◽  
Phase State ◽  
State Diagram ◽  
The State ◽  
Component System ◽  
State Diagrams ◽  
Pearson Symbol

The paper presents the results of the analysis of the state diagram of compounds in the system А12O3-SiO2. It has been found that the presence and the concentration of oxygen have a very important effect on formation of compounds with a crystalline structure in different syngony based on SIALON. Oxygen contributes to transition of the metastable AlXSi3-XN4compound into stable one. The parameter of structural “friability” of compounds has been used in the analysis of thethermodynamic stability of compounds in the Al-Si-N-O system. It has been foundthat the SiAl4O2N4 compound with the 12H-SIALON structure (Pearson symbol hP32) has the greatest thermodynamic stability among the compounds under study in this system.

scholarly journals Size-Dependent Specific Surface Area of Nanoporous Film Assembled by Core-Shell Iron Nanoclusters

2006 ◽  
Vol 2006 ◽  
pp. 1-4 ◽  
Author(s):  
Jiji Antony ◽  
Joseph Nutting ◽  
Donald R. Baer ◽  
Daniel Meyer ◽  
Amit Sharma ◽  
...  
Keyword(s):  
Specific Surface ◽  
Chemical Reactivity ◽  
Calculated Data ◽  
Inert Atmosphere ◽  
Core Shell ◽  
Porous Films ◽  
Shell Nanoparticles ◽  
Size Dependent ◽  
Surface Areas ◽  
Nanoporous Films

Nanoporous films of core-shell iron nanoclusters have improved possibilities for remediation, chemical reactivity rate, and environmentally favorable reaction pathways. Conventional methods often have difficulties to yield stable monodispersed core-shell nanoparticles. We produced core-shell nanoclusters by a cluster source that utilizes combination of Fe target sputtering along with gas aggregations in an inert atmosphere at7∘C. Sizes of core-shell iron-iron oxide nanoclusters are observed with transmission electron microscopy (TEM). The specific surface areas of the porous films obtained from Brunauer-Emmett-Teller (BET) process are size-dependent and compared with the calculated data.

Ligament size-dependent electrocatalytic activity of nanoporous Ag network for CO2 reduction

2018 ◽  
Vol 210 ◽  
pp. 289-299 ◽  
Author(s):  
Wanfeng Yang ◽  
Wensheng Ma ◽  
Zhonghua Zhang ◽  
Chuan Zhao
Keyword(s):  
Size Effects ◽  
Electrocatalytic Activity ◽  
Co2 Reduction ◽  
Size Dependent ◽  
Ligament Size

Nanoporous Ag (ligament size: 21 nm) exhibits superior CO selectivity and activity, confirming strong ligament size effects on CO2 reduction.

A Dimensional Analysis Model for Geometric Size Effects of Single Crystals

2010 ◽  
Vol 97-101 ◽  
pp. 2184-2187
Author(s):  
Xiao Liang Chen ◽  
Shun Hong Lin ◽  
Zuan Tian
Keyword(s):  
Yield Strength ◽  
Single Crystals ◽  
Dimensional Analysis ◽  
Size Effects ◽  
Surface Effect ◽  
Analysis Model ◽  
Size Dependent ◽  
Nano Scale ◽  
Geometric Size ◽  
Metal Single Crystals

Due to the relatively high surface-to-volume ratio, the surface effect can be significant for micro/nano-scale materials. This paper focuses on geometric size-dependent strength mechanisms of micro/nano-scale metal single crystals. A dimensional analysis model relating surface energy with the geometric size-dependent yield strength is presented and compared with results of microscale uniaxial compression tests on Ni and Au single crystals. The results indicate this model can predict the geometric size effects on the yield strength of micro/nano-scale metal single crystals.

Coupling-anisotropy and finite-size effects in interfacial tension of the two-dimensional Ising model

1999 ◽  
Vol 32 (26) ◽  
pp. 4897-4906 ◽  
Author(s):  
Ming-Chya Wu ◽  
Ming-Chang Huang ◽  
Yu-Pin Luo ◽  
Tsong-Ming Liaw
Keyword(s):  
Ising Model ◽  
Interfacial Tension ◽  
Size Effects ◽  
Finite Size ◽  
Two Dimensional ◽  
Finite Size Effects

scholarly journals SIZE-DEPENDENT ELASTIC MODULUS AND FRACTURE TOUGHNESS OF THE NANOFILM WITH SURFACE EFFECTS

2008 ◽  
Vol 15 (05) ◽  
pp. 599-603 ◽  
Author(s):  
JIAN-GANG GUO ◽  
LI-JUN ZHOU ◽  
YA-PU ZHAO
Keyword(s):  
Fracture Toughness ◽  
Elastic Modulus ◽  
Surface Energy ◽  
Size Effects ◽  
Interatomic Potential ◽  
Effective Elastic Modulus ◽  
Surface Effects ◽  
Surface Relaxation ◽  
Ideal Crystal ◽  
Size Dependent

The effective elastic modulus and fracture toughness of the nanofilm were derived with the surface relaxation and the surface energy taken into consideration by means of the interatomic potential of an ideal crystal. The size effects of the effective elastic modulus and fracture toughness were discussed when the thickness of the nanofilm was reduced. And the dependence of the size effects on the surface relaxation and surface energy was also analyzed.

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