scholarly journals Diffusion enhancement of the particle in disorder medium by biased force

2021 ◽  
Vol 70 (19) ◽  
pp. 1-6
Author(s):  
Fan Li-Ming ◽  
◽  
Bao Jing-Dong
Keyword(s):  
Diffusion Enhancement

Thin-felt hollow-B-ZSM-5/SS-fiber catalyst for methanol-to-propylene: Toward remarkable stability improvement from mesoporosity-dependent diffusion enhancement

2019 ◽  
Vol 361 ◽  
pp. 588-598 ◽  
Author(s):  
Jia Ding ◽  
Yingshuai Jia ◽  
Pengjing Chen ◽  
Guofeng Zhao ◽  
Ye Liu ◽  
...  
Keyword(s):  
Diffusion Enhancement

Diffusion Enhancement in Glassy Metals Under Non-Equilibrium Conditions

1995 ◽  
Vol 400 ◽  
Author(s):  
S. Bellini ◽  
G. Mazzone ◽  
A. Montone ◽  
M. Vittori-antisari Enea ◽  
C.R. Casaccia
Keyword(s):  
Free Volume ◽  
Growth Kinetics ◽  
Bulk Diffusion ◽  
High Energy ◽  
First Case ◽  
Diffusion Enhancement ◽  
Glass Crystal ◽  
Kinetics Of ◽  
Crystal Interface ◽  
Diffusion Properties

AbstractThe diffusion properties of a Ni-Zr metallic glass formed at the interface of a bulk diffusion couple have been studied in conditions far from a fully relaxed state. The growth kinetics of the interface film have been enhanced by both plastic deformation and high energy electron irradiation. Different results have been obtained in the two cases, since in the first case the film grows exponentially with time, while in the second case the usual square root dependence on time is observed. This behaviour has been interpreted as a consequence of the annihilation kinetics of the excess free volume introduced in the glass by the above methods. Two different mechanisms of free volume annihilation , namely exchange with a crystal vacancy at the glass-crystal interface and structural relaxation in the bulk glassy phase have been considered to be operative so that the nature of the growth kinetics has been found to depend on the mechanism predominant in each experimental condition.

Effect of Energy and Dose on Transient-Enhanced Diffusion and Defect Microstructure in Low Energy High Dose As+ Implanted Si

1996 ◽  
Vol 438 ◽  
Author(s):  
V. Krishnamoorthy ◽  
D. Venables ◽  
K. Moeller ◽  
K. S. Jones ◽  
B. Freer
Keyword(s):  
Point Defects ◽  
Surface Recombination ◽  
High Dose ◽  
Enhanced Diffusion ◽  
Projected Range ◽  
Diffusion Enhancement ◽  
Defect Microstructures ◽  
Dose Dependent ◽  
Higher Doses ◽  
Defect Microstructure

Abstract(001) CZ silicon wafers were implanted with arsenic (As+) at energies of 10–50keV to doses of 2×1014 to 5×1015/cm2. All implants were amorphizing in nature. The samples were annealed at 700°C for 16hrs. The resultant defect microstructures were analyzed by XTEM and PTEM and the As profiles were analyzed by SIMS. The As profiles showed significantly enhanced diffusion in all of the annealed specimens. The diffusion enhancement was both energy and dose dependent. The lowest dose implant/annealed samples did not show As clustering which translated to a lack of defects at the projected range. At higher doses, however, projected range defects were clearly observed, presumably due to interstitials generated during As clustering. The extent of enhancement in diffusion and its relation to the defect microstructure is explained by a combination of factors including surface recombination of point defects, As precipitation, As clustering and end of range damage.

scholarly journals Vapor flux and recrystallization during dry snow metamorphism under a steady temperature gradient as observed by time-lapse micro-tomography

2012 ◽  
Vol 6 (5) ◽  
pp. 1141-1155 ◽  
Author(s):  
B. R. Pinzer ◽  
M. Schneebeli ◽  
T. U. Kaempfer
Keyword(s):  
Temperature Gradient ◽  
Physical Properties ◽  
Time Lapse ◽  
Phase Changes ◽  
External Temperature ◽  
Vapor Flux ◽  
Snow Metamorphism ◽  
Diffusion Enhancement ◽  
Micro Tomography ◽  
Snow Microstructure

Abstract. Dry snow metamorphism under an external temperature gradient is the most common type of recrystallization of snow on the ground. The changes in snow microstructure modify the physical properties of snow, and therefore an understanding of this process is essential for many disciplines, from modeling the effects of snow on climate to assessing avalanche risk. We directly imaged the microstructural changes in snow during temperature gradient metamorphism (TGM) under a constant gradient of 50 K m−1, using in situ time-lapse X-ray micro-tomography. This novel and non-destructive technique directly reveals the amount of ice that sublimates and is deposited during metamorphism, in addition to the exact locations of these phase changes. We calculated the average time that an ice volume stayed in place before it sublimated and found a characteristic residence time of 2–3 days. This means that most of the ice changes its phase from solid to vapor and back many times in a seasonal snowpack where similar temperature conditions can be found. Consistent with such a short timescale, we observed a mass turnover of up to 60% of the total ice mass per day. The concept of hand-to-hand transport for the water vapor flux describes the observed changes very well. However, we did not find evidence for a macroscopic vapor diffusion enhancement. The picture of {temperature gradient metamorphism} produced by directly observing the changing microstructure sheds light on the micro-physical processes and could help to improve models that predict the physical properties of snow.

scholarly journals Single-molecule diffusometry reveals no catalysis-induced diffusion enhancement of alkaline phosphatase as proposed by FCS experiments

2020 ◽  
Vol 117 (35) ◽  
pp. 21328-21335
Author(s):  
Zhijie Chen ◽  
Alan Shaw ◽  
Hugh Wilson ◽  
Maxime Woringer ◽  
Xavier Darzacq ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Single Molecule ◽  
Particle Tracking ◽  
Single Particle ◽  
Theoretical Models ◽  
Single Particle Tracking ◽  
Correlation Spectroscopy ◽  
Single Molecule Level ◽  
Diffusion Phenomena ◽  
Diffusion Enhancement

Theoretical and experimental observations that catalysis enhances the diffusion of enzymes have generated exciting implications about nanoscale energy flow, molecular chemotaxis, and self-powered nanomachines. However, contradictory claims on the origin, magnitude, and consequence of this phenomenon continue to arise. To date, experimental observations of catalysis-enhanced enzyme diffusion have relied almost exclusively on fluorescence correlation spectroscopy (FCS), a technique that provides only indirect, ensemble-averaged measurements of diffusion behavior. Here, using an anti-Brownian electrokinetic (ABEL) trap and in-solution single-particle tracking, we show that catalysis does not increase the diffusion of alkaline phosphatase (ALP) at the single-molecule level, in sharp contrast to the ∼20% enhancement seen in parallel FCS experiments usingp-nitrophenyl phosphate (pNPP) as substrate. Combining comprehensive FCS controls, ABEL trap, surface-based single-molecule fluorescence, and Monte Carlo simulations, we establish thatpNPP-induced dye blinking at the ∼10-ms timescale is responsible for the apparent diffusion enhancement seen in FCS. Our observations urge a crucial revisit of various experimental findings and theoretical models––including those of our own––in the field, and indicate that in-solution single-particle tracking and ABEL trap are more reliable means to investigate diffusion phenomena at the nanoscale.

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