نتایج جستجو برای: diffusion barrier
تعداد نتایج: 248877 فیلتر نتایج به سال:
We present a functional of nonstandard growth for which the corresponding minimization problem provides a model for image denoising, enhancement, and restoration. The diffusion resulting from the proposed model is a combination of isotropic and anisotropic diffusion. Isotropic diffusion is used at locations with low gradient and total variation based diffusion is used along likely edges. At all...
Experimental P diffusion profile in Si with a constant P surface concentration of 3 ×10 cm −3 at 900°C under an inert atmosphere is shown in Fig. 1. The abscissa is x / t = λ , where x is the distance from a specimen surface and t is the diffusion time. The profile has the plateau, rapid fall and tail. Yoshida et al. studied P diffusion in Si based on the pair diffusion models of the vacancy me...
The measurement of the density of two-dimensional islands by scanning tunneling microscopy after submonolayer growth is used to determine the strain dependence of surface diffusion. Templates of strained and relaxed Ge surfaces with the same surface reconstruction are prepared for comparison. The diffusion barrier for Ge and Si adatoms is found to increase with increasing compressive strain of ...
We apply a Langevin model by imposing additive and multiplicative noises to study thermally activated diffusion over a fluctuating barrier in underdamped dynamics. The barrier fluctuation is characterized by Gaussian colored noise with exponential correlation. We present the exact solutions for the first and second moments. Furthermore, we use direct simulations to calculate the asymptotic prob...
This paper provides a systematic methodology to identify general innovation diffusion patterns in a given case study: First, an analytical framework is introduced which structures a review of innovation diffusion research. This framework may be used to structure the analysis of a case study. Second, a classification of innovation diffusion models is developed by focusing on the analytical hypot...
Throughout life, neural stem cells (NSCs) generate neurons in the mammalian brain. Using photobleaching experiments, we found that during cell division in vitro and within the developing mouse forebrain, NSCs generate a lateral diffusion barrier in the membrane of the endoplasmic reticulum, thereby promoting asymmetric segregation of cellular components. The diffusion barrier weakens with age a...
Background For in-vivo an ex-vivo studies of myocardial structure, generally a spin echo (SE) or stimulated echo (STE) based sequence is used. Diffusion weighting is reported with a large range of diffusion times (50 and 1000 ms). Furthermore, in-vivo studies generally use low b-values (300 s/mm) whereas ex-vivo experiments allow for much higher b-values. For interpretation of in-vivo cardiac D...
A diffusion barrier at the transition zone enables the compartmentalization of signaling molecules by cilia. The BBSome and the small guanosine triphosphatase Arl6, which triggers BBSome coat polymerization, are required for the exit of activated signaling receptors from cilia, but how diffusion barriers are crossed when membrane proteins exit cilia remains to be determined. In this study, we f...
The reduction of the diffusion energy barrier for Li in electrodes is one of the required criteria to achieve better performances in Li ion batteries. Using density functional theory based calculations, we report a pressure induced manifold enhancement of Li-kinetics in bulk FCC fullerene. Scanning of the potential energy surface reveals a diffusion path with a low energy barrier of 0.62 eV, wh...
Large size self-assembled quantum rings: quantum size effect and modulation on the surface diffusion
We demonstrate experimentally the submicron size self-assembled (SA) GaAs quantum rings (QRs) by quantum size effect (QSE). An ultrathin In0.1 Ga0.9As layer with different thickness is deposited on the GaAs to modulate the surface nucleus diffusion barrier, and then the SA QRs are grown. It is found that the density of QRs is affected significantly by the thickness of inserted In0.1 Ga0.9As, an...
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