scholarly journals Modeling for gas dissolution and diffusion in water-intrusion coal seam and its potential applications

Fuel ◽  
2022 ◽  
Vol 307 ◽  
pp. 121786
Author(s):  
Leilei Si ◽  
Hongyang Wang ◽  
Yujun Xi ◽  
Zhihui Wen ◽  
Banghua Yao
Keyword(s):  
Coal Seam ◽  
Water Intrusion ◽  
Potential Applications ◽  
And Diffusion

Epitaxial Growth of III-V Nanowires on Group IV Substrates

2008 ◽  
Vol 1068 ◽  
Author(s):  
Erik Bakkers ◽  
Magnus Borgstrom ◽  
Marcel Verheijen
Keyword(s):  
Epitaxial Growth ◽  
High Performance ◽  
Lattice Strain ◽  
Active Element ◽  
Nucleation Site ◽  
Group Iv ◽  
Semiconducting Nanowires ◽  
Potential Applications ◽  
High Level ◽  
And Diffusion

ABSTRACTSemiconducting nanowires are emerging as a route to combine heavily mismatched materials. The high level of control on wire dimensions and chemical composition makes them promising materials to be integrated in future silicon technologies as well as to be the active element in optoelectronic devices.In this article, we review the recent progress in epitaxial growth of nanowires on non-corresponding substrates. We highlight the advantage of using small dimensions to facilitate accommodation of the lattice strain at the surface of the structures. More specifically, we will focus on the growth of III–V nanowires on group IV substrates. This approach enables the integration of high-performance III–V semiconductors monolithically into mature silicon technology, since fundamental issues of III–V integration on Si such as lattice and thermal expansion mismatch can be overcome. Moreover, as there will only be one nucleation site per crystallite, the system will not suffer from antiphase boundaries.Issues that affect the electronic properties of the heterojunction, such as the crystallographic quality and diffusion of elements across the heterointerface will be discussed. Finally, we address potential applications of vertical III–V nanowires grown on silicon.

scholarly journals Molecular Dynamics Study of Stability and Diffusion of Graphene-Based Drug Delivery Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Xiunan Wang ◽  
Yi Liu ◽  
Jingcheng Xu ◽  
Shengjuan Li ◽  
Fada Zhang ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Molecular Dynamics ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Graphene Sheets ◽  
Pristine Graphene ◽  
Drug Molecules ◽  
Potential Applications ◽  
The Stability ◽  
And Diffusion

Graphene, a two-dimensional nanomaterial with unique biomedical properties, has attracted great attention due to its potential applications in graphene-based drug delivery systems (DDS). In this work graphene sheets with various sizes and graphene oxide functionalized with polyethylene glycol (GO-PEG) are utilized as nanocarriers to load anticancer drug molecules including CE6, DOX, MTX, and SN38. We carried out molecular dynamics calculations to explore the energetic stabilities and diffusion behaviors of the complex systems with focuses on the effects of the sizes and functionalization of graphene sheets as well as the number and types of drug molecules. Our study shows that the binding of graphene-drug complex is favorable when the drug molecules and finite graphene sheets become comparable in sizes. The boundaries of finite sized graphene sheets restrict the movement of drug molecules. The double-side loading often slows down the diffusion of drug molecules compared with the single-side loading. The drug molecules bind more strongly with GO-PEG than with pristine graphene sheets, demonstrating the advantages of functionalization in improving the stability and biocompatibility of graphene-based DDS.

Modeling of gas migration in water-intrusion coal seam and its inducing factors

Fuel ◽  
2017 ◽  
Vol 210 ◽  
pp. 398-409 ◽  
Author(s):  
Leilei Si ◽  
Zenghua Li ◽  
Yongliang Yang ◽  
Jun Zhou ◽  
Yinbo Zhou ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gas Migration ◽  
Water Intrusion ◽  
Inducing Factors

scholarly journals Production analysis for fractured vertical well in rectangular coal reservoirs

2018 ◽  
Vol 73 ◽  
pp. 62
Author(s):  
Chen Li ◽  
Zhenzhen Dong ◽  
Xiang Li
Keyword(s):  
Coal Seam ◽  
Analytical Solutions ◽  
Methane Production ◽  
Coalbed Methane ◽  
Finite Conductivity ◽  
Storage Coefficient ◽  
Vertical Well ◽  
Production Analysis ◽  
Coalbed Methane Production ◽  
And Diffusion

As one kind of unconventional natural gas, coalbed methane is an important energy resource that is subject to active research. Gas exists in coalbed methane reservoirs in two forms: free gas and adsorbed gas. In the course of coalbed methane production, the reservoir experiences pressure decrease, desorption, diffusion, and seepage. Previous models of coalbed methane production were mainly concerned with circular boundaries. However, field tests revealed that some fractured wells possess the characteristics of rectangular boundaries. For fractured rectangular coalbed methane reservoirs, it is necessary to deal with the four boundaries with mirror image theory, which complicates calculations. In addition, the desorption and adsorption process of coalbed methane exerts a strong effect on the seepage process. Furthermore, the complexity of the rectangular coal seam embedded with the finite-conductivity fracture results in a significant computational challenge. For the first time, this paper presented a fast analytical solution for a finite-conductivity fractured vertical well model with either rectangular closed or constant-pressure boundaries in the coal seam. On the basis of the Fick diffusion law and the Darcy seepage law, a mathematical model that considers diffusion in matrix and seepage within natural fractures was established. Then, we integrated the fracture conductivity function method with the hydraulic fracture model to greatly increase computational efficiency. The analytical solutions were validated against a numerical simulation. Parameter sensitivity analysis reveals that interporosity coefficient and storage coefficient, respectively, affect the appearance time and degree of desorption and diffusion. Desorption coefficient mainly describes the capacity of desorption and diffusion. Well storage coefficient, conductivity factor, and skin factor mainly affect the early stage of production. Finally, the proposed solutions were applied to field history match. The model developed is applicable to production analysis and well testing for coalbed methane reservoirs. The new proposed model extended flow mechanism of coalbed methane, and provided a better production and pressure forecast for coalbed methane reservoirs. In addition, the analytical solutions can be used to generate type curves for fractured vertical wells with finite conductivity and in the rectangular boundary, and provide a sound theoretical basis for well tests in the coal seam. The model is also applicable to other types of unconventional gas reservoirs, such as gas shales, in which the same processes are present.

Dissolution characteristics of gas in mine water and its application on gas pressure measurement of water-intrusion coal seam

Fuel ◽  
2022 ◽  
Vol 313 ◽  
pp. 123004
Author(s):  
Leilei Si ◽  
Yujun Xi ◽  
Jianping Wei ◽  
Bo Li ◽  
Hongyang Wang ◽  
...  
Keyword(s):  
Coal Seam ◽  
Pressure Measurement ◽  
Mine Water ◽  
Gas Pressure ◽  
Water Intrusion

scholarly journals BAI-Net: Individualized Human Cerebral Cartography using Graph Convolutional Network

2021 ◽  
Author(s):  
Liang Ma ◽  
Yu Zhang ◽  
Hantian Zhang ◽  
Luqi Cheng ◽  
Junjie Zhuo ◽  
...  
Keyword(s):  
Neurological Disorders ◽  
Brain Atlas ◽  
Brain Morphology ◽  
Convolutional Network ◽  
Neuroscience Research ◽  
Potential Applications ◽  
And Function ◽  
Cortical Morphology ◽  
Functional Areas ◽  
And Diffusion

Individualized human cerebral cartography has drawn considerable attention in neuroscience research. But many challenges remain, mainly due to large cross-subject variations in brain morphology, connectivity, and function. We developed a new tool called brain atlas individualization network (BAI-Net) that automatically parcels individual cerebral cortex into segregated functional areas using structural and diffusion MRIs. The presented method integrates the group priors into the loss function of graph convolution network, and learns the connectivity context of anatomical fingerprints for each area on individual brain graphs. The presented model provides reliable, efficient and explainable individual cortical parcellations across multiple sessions with different scanners. Moreover, it keeps highly group consistence as well as individual-specific variations. Given the reliable inter-subject variabilities from BAI-Net parcellation, their functional connectome showed higher associations with individual behavioral scores in a cognitive battery, compared to the individualized methods. The presented model has potential applications in locating more individual-specific regions in the diagnosis and treatment of neurological disorders, rather than group-registered method in terms of cortical morphology. And its methodology could be applied to individualize many population brain atlases.

Epitaxial Growth of III-V Nanowires on Group IV Substrates

MRS Bulletin ◽  
2007 ◽  
Vol 32 (2) ◽  
pp. 117-122 ◽  
Author(s):  
Erik P. A. M. Bakkers ◽  
Magnus T. Borgström ◽  
Marcel A. Verheijen
Keyword(s):  
Epitaxial Growth ◽  
Lattice Strain ◽  
Active Element ◽  
Nucleation Site ◽  
Group Iv ◽  
Thermal Expansion Mismatch ◽  
Semiconducting Nanowires ◽  
Potential Applications ◽  
High Level ◽  
And Diffusion

AbstractSemiconducting nanowires are emerging as a route to combine heavily mismatched materials. The high level of control on wire dimensions and chemical composition makes them promising materials to be integrated in future silicon technologies as well as to be the active element in optoelectronic devices.This ar ticle reviews the recent progress in epitaxial growth of nanowires on non-corresponding substrates. We highlight the advantage of using small dimensions to facilitate accommodation of the lattice strain at the surface of the structures. More specifically, we will focus on the growth of III-V nanowires on Group IV substrates. This approach enables the integration of high-perform ance III-V semiconductors monolithically into mature silicon technology, since fundamental issues of III-V integration on Si such as lattice and thermal expansion mismatch can be overcome. Moreover, as there will only be one nucleation site per crystallite, the system will not suffer from antiphase boundaries.Issues that affect the electronic properties of the heterojunction, such as the crystallographic quality and diffusion of elements across the heterointerface, will be discussed. Finally, we address potential applications of vertical III-V nanowires grown on silicon.

Meridional Circulation, Turbulence, and Diffusion Processes in Stars

1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair
Keyword(s):  
Convection Zone ◽  
Diffusion Processes ◽  
Meridional Circulation ◽  
Diffusion Time ◽  
Work In Progress ◽  
First Results ◽  
Stellar Envelopes ◽  
And Diffusion ◽  
Turbulence And Diffusion ◽  
Hr Diagram

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

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