Selection of lamellar thickness in polymer crystal growth: A rate-theory model

1988 ◽  
Vol 38 (8) ◽  
pp. 5684-5693 ◽  
Author(s):  
David M. Sadler ◽  
George H. Gilmer
2011 ◽  
Vol 60 (3) ◽  
pp. 895-936
Author(s):  
Pierre Cardaliaguet ◽  
Olivier Ley ◽  
Aurelien Monteillet

Author(s):  
Shenyang HU ◽  
Yulan Li ◽  
Shunli Shang ◽  
Zi-Kui Liu ◽  
Douglas Burkes ◽  
...  

Abstract Gamma lithium aluminate (LiAlO2) is a breeder material for tritium and is one of key components in a tritium-producing burnable absorber rod (TPBAR). Dissolution and precipitation of second phases such as LiAl5O8 and voids are observed in irradiated LiAlO2. Such microstructure changes cause the degradation of thermomechanical properties of LiAlO2 and affect tritium retention and release kinetics, and hence, the TPBAR performance. In this work, a microstructure-dependent model of radiation-induced segregation (RIS) has been developed for investigating the accumulation of species and phase stability in polycrystalline LiAlO2 structures under irradiation. Three sublattices (i.e., [Li, Al, V]I [O, Vo]II [Lii, Ali, Oi, Vi]III), and concentrations of six diffusive species (i.e., Li; vacancy of Li or Al at [Li, Al, V]I sublattice, O vacancy at [O, Vo]II sublattice, and Li, Al and O interstitials at [Lii, Ali, Oi, Vi]III interstitial sublattices; are used to describe spatial and temporal distributions of defects and chemistry. Microstructure-dependent thermodynamic and kinetic properties including the generation, reaction, and chemical potentials of defects and defect mobility are taken into account in the model. The parametric studies demonstrated the capability of the developed RIS model to assess the effect of thermodynamic and kinetic properties of defects on the segregation and depletion of species in polycrystalline structures and to explain the phase stability observed in irradiated LiAlO2 samples. The developed RIS model will be extended to study the precipitation of LiAl5O8 and voids and tritium retention by integrating the phase-field method.


2008 ◽  
Vol 27 (4) ◽  
pp. 313-320
Author(s):  
Hua Li ◽  
Jing Chang ◽  
Ming Dong

2018 ◽  
Vol 913 ◽  
pp. 237-246 ◽  
Author(s):  
Yan Xia Yu ◽  
Li Ping Guo ◽  
Zheng Yu Shen ◽  
Yun Xiang Long ◽  
Zhong Cheng Zheng ◽  
...  

The average size and density evolution of dislocation loops in AL-6XN austenitic stainless steel, a candidate fuel cladding material for supercritical water-cooled reactor, under proton irradiation were simulated through a rate theory model. The simulation results exhibit relatively good agreement with the experimental results at 563 K. The size and density of defect clusters are calculated under irradiation temperature between 550 K and 900 K and irradiation doses up to 15 dpa which satisfies the working condition in supercritical water-cooled reactor. The fast nucleation between self-interstitials happens at the initial stage of irradiation. The average size of dislocation loops increases while the average density of these loops reduces with the increasing temperature, and the average density approaches to a constant when irradiated at higher irradiation doses. The mechanism is discussed based on the variation of rate constants of defect reactions and the variation of the diffusion coefficients of interstitials and dislocation loops with dose and temperature.


1995 ◽  
Vol 268 (3) ◽  
pp. C636-C646 ◽  
Author(s):  
J. L. Overholt ◽  
A. Saulino ◽  
M. L. Drumm ◽  
R. D. Harvey

Whole cell epithelial cystic fibrosis transmembrane conductance regulator (CFTR) Cl- currents exhibited a linear current-voltage (I-V) relationship with high symmetrical transmembrane Cl- concentrations. However, when intracellular Cl- (Cli-) was reduced by replacement with glutamate, I-V relationships were outwardly rectifying. Rectification was not affected by reducing extracellular Cl- to eliminate or reverse the gradient, indicating that rectification is not a function of the Cl- gradient. Rectification was affected by Cli- in a concentration-dependent manner, and it was weaker when Cli- was reduced by replacement with sucrose. These characteristics are identical to those of the cardiac isoform of CFTR, and the experimental data could be simulated by an Eyring rate theory model assuming that permeating anions interact at a single binding site within the channel pore. No evidence was found for multiple binding sites. These results indicate that rectification is a function of the concentration and permeability of the anions inside the cell. It is concluded that rectification of CFTR Cl- current is a property of ion channel permeation that would occur under physiological conditions and that permeation of the epithelial and cardiac isoforms of CFTR is identical.


2013 ◽  
Vol 662 ◽  
pp. 243-248
Author(s):  
Wen Yuan Deng

The optical characterization of LaF3 thin film in DUV spectral range was experimental investigated by using a variable angle purged UV spectroscopic ellipsometer. In order to take into account the inhomogeneity, a theory model that dividing the single thin film into several sublayers was adopted. Two kinds of LaF3 thin films fabricated on fused silicate substrate with different substrates temperature were tested. From the obtained optical index and the physical thickness of different sublayer in the two different kinds of LaF3 thin films, it was found that, the inhomogeneity of the LaF3 thin film deposited with substrate temperature at 300°C was stronger than that of the LaF3 thin film deposited with substrate temperature at 250°C, indicating that the substrate temperature has important influence on the optical index and inhomogeneity of LaF3 thin films. For both of the two kinds LaF3 thin films, the agreement between the measured transmittance and the simulated transmittance using the parameters from regression of SE was nice, indicating that the selection of the material dispersion law and regression procedure were successful.


2008 ◽  
Vol 1125 ◽  
Author(s):  
Ken-ichi Ebihara ◽  
Masatake Yamaguchi ◽  
Hideo Kaburaki ◽  
Yutaka Nishiyama

ABSTRACTWe have evaluated phosphorus (P) segregation in ion-irradiated nickel (Ni) by the rate theory model incorporating the results of first principles calculations. We find from our first principles calculation that the transport of P via the rotation mode of a mixed-dumbbell is unlikely to occur, and the transport coefficient of phosphorus by the vacancy mechanism is much larger than that reported previously. On the basis of our first principles results, we have also proposed to include the effect of free migration of P via the octahedral interstitial site of FCC Ni crystal in the rate theory model. With all these renewed parameters, we have successfully obtained the P distribution in irradiated Ni, which is very close to experiment, by adjusting the effect of P transport by the vacancy mechanism.


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