scholarly journals A Computational Study of Aspects of ZnO Nanorod  Film Electro-Crystallisation

2021 ◽  
Author(s):  
◽  
Jade River Mackay
Keyword(s):  
Zinc Oxide ◽  
Transport Model ◽  
Computational Study ◽  
Field Variation ◽  
Nano Structure ◽  
Crystallite Shape ◽  
Electric Field Variation ◽  
New Generation ◽  
Selection Of ◽  
The Continuum

<p>A new generation of material technologies is being produced by tuning the properties of an existing material through control of the size and shape on the nanoscale. Zinc oxide is an excellent candidate for such an approach due to its possession of a plethora of useful properties, both mechanical and electronic, and a fantastically rich family of morphologies accessible on the nanoscale. A more detailed control over the nano-structure of these materials requires a more detailed understanding of the events that control the growth. We have undertaken computational studies of the electrodeposition of zinc oxide nano-rod films to open up and improve the understanding of the pathways, and events that facilitate the controlled selection of desired structures and therefore properties. We have applied methods that span vastly different scales to provide insight on the continuum and atomistic regimes. Specifically, we have developed a macroscopic transport model to track the evolution of crystallite shape, surrounding concentration distributions, and electric field variation. The macroscopic view is complemented with a classical description of crystal growth, in which we obtain the key parameters using quantum mechanical calculations.</p>

scholarly journals A Computational Study of Aspects of ZnO Nanorod  Film Electro-Crystallisation

2021 ◽  
Author(s):  
◽  
Jade River Mackay
Keyword(s):  
Zinc Oxide ◽  
Transport Model ◽  
Computational Study ◽  
Field Variation ◽  
Nano Structure ◽  
Crystallite Shape ◽  
Electric Field Variation ◽  
New Generation ◽  
Selection Of ◽  
The Continuum

<p>A new generation of material technologies is being produced by tuning the properties of an existing material through control of the size and shape on the nanoscale. Zinc oxide is an excellent candidate for such an approach due to its possession of a plethora of useful properties, both mechanical and electronic, and a fantastically rich family of morphologies accessible on the nanoscale. A more detailed control over the nano-structure of these materials requires a more detailed understanding of the events that control the growth. We have undertaken computational studies of the electrodeposition of zinc oxide nano-rod films to open up and improve the understanding of the pathways, and events that facilitate the controlled selection of desired structures and therefore properties. We have applied methods that span vastly different scales to provide insight on the continuum and atomistic regimes. Specifically, we have developed a macroscopic transport model to track the evolution of crystallite shape, surrounding concentration distributions, and electric field variation. The macroscopic view is complemented with a classical description of crystal growth, in which we obtain the key parameters using quantum mechanical calculations.</p>

Bifluoride Ion Mediated SuFEx Trifluoromethylation of Sulfonyl Fluorides and Iminosulfur Oxydifluorides

2018 ◽  
Author(s):  
Christopher J. Smedley ◽  
Bing Gao ◽  
Suhua Li ◽  
Qinheng Zheng ◽  
Andrew Molino ◽  
...  
Keyword(s):  
Breast Cancer Cells ◽  
Catalytic Mechanism ◽  
Bioactive Molecules ◽  
Chromatographic Purification ◽  
Rapid Exchange ◽  
Nucleophilic Displacement ◽  
Sulfur Fluoride ◽  
Reactions With Nucleophiles ◽  
New Generation ◽  
Selection Of

Sulfur-Fluoride Exchange (SuFEx) is the new generation click chemistry transformation exploiting the unique properties of S-F bonds and their ability to undergo near-perfect reactions with nucleophiles. We report here the first SuFEx based protocol for the efficient synthesis of pharmaceutically important triflones and bis(trifluoromethyl)sulfur oxyimines from the corresponding sulfonyl fluorides and iminosulfur oxydifluorides, respectively. The new protocol involves the rapid exchange of the S-F bond with trifluoromethyltrimethylsilane (TMSCF<sub>3</sub>) upon activation with potassium bifluoride in anhydrous DMSO. The reaction tolerates a wide selection of substrates and proceeds under mild conditions without need for chromatographic purification. A tentative catalytic mechanism is proposed supported by DFT calculations, involving formation of the free trifluoromethyl anion followed by nucleophilic displacement of the S-F through a five-coordinate intermediate. The preparation of a benzothiazole derived bis(trifluoromethyl)sulfur oxyimine with cytotoxic selectivity for MCF7 breast cancer cells demonstrates the utility of this methodology for the late-stage functionalization of bioactive molecules.<br>

scholarly journals First steps towards the assimilation of IASI ozone data into the MOCAGE-PALM system

2009 ◽  
Vol 9 (2) ◽  
pp. 6691-6737 ◽  
Author(s):  
S. Massart ◽  
C. Clerbaux ◽  
D. Cariolle ◽  
A. Piacentini ◽  
S. Turquety ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Total Ozone ◽  
Transport Model ◽  
Polar Regions ◽  
Observation Error ◽  
Random Errors ◽  
Chemistry Transport Model ◽  
Ozone Data ◽  
The One ◽  
New Generation

Abstract. The Infrared Atmospheric Sounding Interferometer (IASI) is one of the five European new generation instruments carried by the polar-orbiting MetOp-A satellite. Data assimilation is a powerful tool to combine these data with a numerical model. This paper presents the first steps made towards the assimilation of the total ozone columns from the IASI measurements into a chemistry transport model. The IASI ozone data used are provided by an inversion of radiances performed at the LATMOS (Laboratoire Atmosphères, Milieux, Observations Spatiales). As a contribution to the validation of this dataset, the LATMOS-IASI data are compared to a four dimensional ozone field, with low systematic and random errors compared to ozonesondes and OMI-DOAS data. This field results from the combined assimilation of ozone profiles from the MLS instrument and of total ozone columns from the SCIAMACHY instrument. It is found that on average, the LATMOS-IASI data tends to overestimate the total ozone columns by 2% to 8%. The random observation error of the LATMOS-IASI data is estimated to about 6%, except over polar regions and deserts where it is higher. Using this information, the LATMOS-IASI data are then assimilated, combined with the MLS data. This first LATMOS-IASI data assimilation experiment shows that the resulting analysis is quite similar to the one obtained from the combined MLS and SCIAMACHY data assimilation.

Computational Study of Grooved Microchannel Enhancements

2008 ◽  
Author(s):  
Stephen A. Solovitz
Keyword(s):  
Thermal Management ◽  
Computational Study ◽  
Internal Flow ◽  
Reynolds Numbers ◽  
Thermal Dissipation ◽  
Two Dimensional ◽  
Macro Scale ◽  
Flow Heat ◽  
Alternate Solution ◽  
Selection Of

As electronics devices continue to increase in thermal dissipation, novel methods will be necessary for effective thermal management. Many macro-scale enhancement techniques have been developed to improve internal flow heat transfer, with a dimple feature being particularly promising due to its enhanced mixing with potentially little pressure penalty. However, because dimples may be difficult to fashion in microchannels, two-dimensional grooves are considered here as a similar alternate solution. Computational fluid dynamics methods are used to analyze the flow and thermal performance for a groove-enhanced microchannel, and the effectiveness is determined for a range of feature depths, diameters, and flow Reynolds numbers. By producing local impingement and flow redevelopment downstream of the groove, thermal enhancements on the order of 70% were achieved with pressure increases of only 30%. Further optimization of this concept should allow the selection of an appropriate application geometry, which can be studied experimentally to validate the concept.

Negative Capacitance Effect on MOS Structure: Influence of Electric Field Variation

2020 ◽  
Vol 19 ◽  
pp. 168-171 ◽  
Author(s):  
Kitae Lee ◽  
Junil Lee ◽  
Sihyun Kim ◽  
Ryoongbin Lee ◽  
Soyoun Kim ◽  
...  
Keyword(s):  
Electric Field ◽  
Negative Capacitance ◽  
Field Variation ◽  
Mos Structure ◽  
Capacitance Effect ◽  
Electric Field Variation

scholarly journals Quantitative Spectroscopy of Wolf-Rayet Stars

1988 ◽  
Vol 108 ◽  
pp. 133-140
Author(s):  
W. Schmutz
Keyword(s):  
Representative Point ◽  
Dimensional Model ◽  
Model Calculations ◽  
One Dimensional ◽  
The Past ◽  
First Results ◽  
The One ◽  
Expanding Atmospheres ◽  
New Generation ◽  
The Continuum

Advances in theoretical modeling of rapidly expanding atmospheres in the past few years made it possible to determine the stellar parameters of the Wolf-Rayet stars. This progress is mainly due to the improvement of the models with respect to their spatial extension: The new generation of models treat spherically-symmetric expanding atmospheres, i.e. the models are one-dimensional. Older models describe the wind by only one representative point. The older models are in fact ‘core-halo’ approximations. They have been introduced by Castor and van Blerkom (1970), and were extensively employed in the past (cf. e.g. Willis and Wilson, 1978; Smith and Willis, 1982). First results from new one-dimensional model calculations are published by Hillier (1984), Schmutz (1984), Hamann (1985), Hillier (1986), and Schmutz et al. (1987a); more detailed results are presented by Schmutz and Hamann (1986), Hamann and Schmutz (1987), Hillier (1987a,b), Wessolowski et al. (1987), Hillier (1987c) and Hamann et al. (1987). These results demonstrate that the step from zero- to one-dimensional calculations is essential. The important point is that the complicated interrelation between NLTE-level populations and radiation field is treated adequately (Schmutz and Hamann, 1986; Hillier, 1987). For this interrelation it is crucial to model consistently not only the line-formation region, but also the layers where the continuum is emitted. In fact, it is the core-halo approximation that causes the one-point models to fail in certain aspects.

Study on the Geo-Electric Field Variation of Sichuan LushanMS7.0 and WenchuanMS8.0 Earthquake

2013 ◽  
Vol 56 (6) ◽  
pp. 721-730
Author(s):  
AN Zhang-Hui ◽  
DU Xue-Bin ◽  
TAN Da-Cheng ◽  
FAN Ying-Ying ◽  
LIU Jun ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Variation ◽  
Electric Field Variation

Life Extending Advanced Component Repairs — Field Operating Experience

2000 ◽  
Author(s):  
Lloyd A. Cooke
Keyword(s):  
Powder Metallurgy ◽  
Gas Turbine ◽  
Operating Experience ◽  
High Strength ◽  
Operating Environment ◽  
Repair Materials ◽  
New Generation ◽  
Filler Metals ◽  
Selection Of ◽  
Repair Techniques

Advanced repair technologies have been introduced to the gas turbine industry over recent years. An increasing selection of coating systems is available which can be tailored to the specific operating environment. Automated welding systems and the use of custom weld filler metals for enhanced component life provide a means of reliably welding the new generation of high strength turbine blade alloys. Powder metallurgy processes have been introduced as an alternative to welding and have been used to upgrade certain components by employing higher strength repair materials than the original castings. In the paper, these and other technologies are assessed based on engine operating experience with direct comparison to the conventional repair techniques which they have replaced.

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