scholarly journals Characterization of Local Structures of Chaotic Attractors in Terms of Coarse-Grained Local Expansion Rates

1988 ◽  
Vol 80 (5) ◽  
pp. 809-826 ◽  
Author(s):  
H. Hata ◽  
T. Horita ◽  
H. Mori ◽  
T. Morita ◽  
K. Tomita
Keyword(s):  
Coarse Grained ◽  
Chaotic Attractors ◽  
Local Expansion ◽  
Local Structures

scholarly journals Biophysical characterization of the SARS-CoV-2 E protein

2021 ◽  
Author(s):  
Aujan Mehregan ◽  
Sergio Perez-Conesa ◽  
Yuxuan Zhuang ◽  
Ahmad Elbahnsi ◽  
Diletta Pasini ◽  
...  
Keyword(s):  
Recombinant Expression ◽  
Structural Data ◽  
Md Simulations ◽  
Full Length ◽  
Coarse Grained ◽  
Biophysical Characterization ◽  
Viral Budding ◽  
Nmr Structures ◽  
E Protein

SARS-CoV-2 is the virus responsible for the COVID-19 pandemic which continues to wreak havoc across the world, over a year and a half after its effects were first reported in the general media. Current fundamental research efforts largely focus on the SARS-CoV-2 Spike protein. Since successful antiviral therapies are likely to target multiple viral components, there is considerable interest in understanding the biophysical role of its other proteins, in particular structural membrane proteins. Here, we have focused our efforts on the characterization of the full-length E protein from SARS-CoV-2, combining experimental and computational approaches. Recombinant expression of the full-length E protein from SARS-CoV-2 reveals that this membrane protein is capable of independent multimerization, possibly as a tetrameric or smaller species. Fluorescence microscopy shows that the protein localizes intracellularly, and coarse-grained MD simulations indicate it causes bending of the surrounding lipid bilayer, corroborating a potential role for the E protein in viral budding. Although we did not find robust electrophysiological evidence of ion-channel activity, cells transfected with the E protein exhibited reduced intracellular Ca2+, which may further promote viral replication. However, our atomistic MD simulations revealed that previous NMR structures are relatively unstable, and result in models incapable of ion conduction. Our study highlights the importance of using high-resolution structural data obtained from a full-length protein to gain detailed molecular insights, and eventually permitting virtual drug screening.

scholarly journals Characterization of Coarse-Grained Heat-Affected Zones in Al and Ti-Deoxidized Offshore Steels

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1096
Author(s):  
Henri Tervo ◽  
Antti Kaijalainen ◽  
Vahid Javaheri ◽  
Satish Kolli ◽  
Tuomas Alatarvas ◽  
...  
Keyword(s):  
Prior Austenite ◽  
Electron Backscatter Diffraction ◽  
Coarse Grained ◽  
Grain Coarsening ◽  
Austenite Grain ◽  
The Matrix ◽  
Backscatter Diffraction ◽  
Prior Austenite Grain ◽  
Deoxidation Practice

Deterioration of the toughness in heat-affected zones (HAZs) due to the thermal cycles caused by welding is a known problem in offshore steels. Acicular ferrite (AF) in the HAZ is generally considered beneficial regarding the toughness. Three experimental steels were studied in order to find optimal conditions for the AF formation in the coarse-grained heat-affected zone (CGHAZ). One of the steels was Al-deoxidized, while the other two were Ti-deoxidized. The main focus was to distinguish whether the deoxidation practice affected the AF formation in the simulated CGHAZ. First, two different peak temperatures and prolonged annealing were used to study the prior austenite grain coarsening. Then, the effect of welding heat input was studied by applying three cooling times from 800 °C to 500 °C in a Gleeble thermomechanical simulator. The materials were characterized using electron microscopy, energy-dispersive X-ray spectrometry, and electron backscatter diffraction. The Mn depletion along the matrix-particle interface was modelled and measured. It was found that AF formed in the simulated CGHAZ of one of the Ti-deoxidized steels and its fraction increased with increasing cooling time. In this steel, the inclusions consisted mainly of small (1–4 μm) TiOx-MnS, and the tendency for prior austenite grain coarsening was the highest.

Characterization of the Local Structures of Ti-MCM-41 and Their Photocatalytic Reactivity for the Decomposition of NO into N2and O2

2006 ◽  
Vol 110 (4) ◽  
pp. 1680-1685 ◽  
Author(s):  
Yun Hu ◽  
Gianmario Martra ◽  
Jinlong Zhang ◽  
Shinya Higashimoto ◽  
Salvatore Coluccia ◽  
...  
Keyword(s):  
Local Structures ◽  
Decomposition Of No ◽  
Mcm 41

scholarly journals Microstructural and Mechanical Characterization of Multilayered Iron Electrodeposits

2011 ◽  
Vol 409 ◽  
pp. 474-479 ◽  
Author(s):  
C. Chan ◽  
J.L. McCrea ◽  
G. Palumbo ◽  
Uwe Erb
Keyword(s):  
Mechanical Properties ◽  
Columnar Structure ◽  
Multilayered Structure ◽  
Structure Design ◽  
Coarse Grained ◽  
Fine Grained ◽  
Microstructure And Mechanical Properties ◽  
Fine Grained Structure ◽  
Iron Coatings

Monolithic and multilayered iron electrodeposits were successfully synthesized by the pulse plating electrodeposition method. Electron microscopy and Vickers microhardness measurements were used to investigate the microstructure and mechanical properties of the iron electrodeposits produced. Two types of monolithic iron coatings were produced, one with a coarse grained, columnar structure and the other with an ultra-fine grained structure. Hall-Petch type grain size strengthening was observed in these monolithic coatings. Multilayered iron coatings composed of alternating layers of coarse grained and fine grained structures were also produced. The hardness value of the multilayered coatings falls between the hardness values for the two types of monolithic coatings produced. This study has demonstrated the possibility of applying a multilayered structure design to tailor the microstructure and mechanical properties of electrodeposited iron coatings.

scholarly journals Peculiar Structural Effects in Pure and Doped Functional Single Crystals of Complex Compositions

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2451
Author(s):  
Galina Kuz’micheva ◽  
Irina Kaurova
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Functional Materials ◽  
Local Environment ◽  
Structural Effects ◽  
Local Structures ◽  
Annealing Conditions ◽  
Activator Ions

Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained. A change in crystal symmetry due to crystal–chemical and growth reasons is considered. The use of structural analysis and X-ray absorption spectroscopy is substantiated to reveal the role of activator ions in the formation of statistical and local structures, respectively. A relationship between the distribution of activator ions over crystallographic sites and photoluminescent parameters of materials is established, which allows selecting optimal systems for the application. The combined results of studying single-crystal compounds of other classes (huntite, sillenite, whitlockite, garnet, tetragonal bronzes) allow formulating and summarizing structural effects that appeared in the systems and caused by various factors and, in many cases, due to the local environment of cations. A principal difference in the structural behavior of solid solutions and doped compounds is shown. The methodology developed for single-crystal samples of complex compositions can be recommended for the systematic structural studies of functional materials of different compositions.

CHARACTERIZATION OF CHAOTIC ATTRACTORS INSIDE BAND-MERGING SCENARIO IN A ZAD-CONTROLLED BUCK CONVERTER

2012 ◽  
Vol 22 (10) ◽  
pp. 1230034
Author(s):  
JOHN ALEXANDER TABORDA ◽  
FABIOLA ANGULO ◽  
GERARD OLIVAR
Keyword(s):  
Control Strategy ◽  
Control Parameter ◽  
Period Doubling ◽  
Basins Of Attraction ◽  
Buck Converter ◽  
Chaotic Attractors ◽  
Complex Dynamic ◽  
Self Similar ◽  
Dynamic Links

Zero Average Dynamics (ZAD) control strategy has been developed, applied and widely analyzed in the last decade. Numerous and interesting phenomena have been studied in systems controlled by ZAD strategy. In particular, the ZAD-controlled buck converter has been a source of nonlinear and nonsmooth phenomena, such as period-doubling, merging bands, period-doubling bands, torus destruction, fractal basins of attraction or codimension-2 bifurcations. In this paper, we report a new bifurcation scenario found inside band-merging scenario of ZAD-controlled buck converter. We use a novel qualitative framework named Dynamic Linkcounter (DLC) approach to characterize chaotic attractors between consecutive crisis bifurcations. This approach complements the results that can be obtained with Bandcounter approaches. Self-similar substructures denoted as Complex Dynamic Links (CDLs) are distinguished in multiband chaotic attractors. Geometrical changes in multiband chaotic attractors are detected when the control parameter of ZAD strategy is varied between two consecutive crisis bifurcations. Linkcount subtracting staircases are defined inside band-merging scenario.

Fabrication of MEMS Components Based on Ultrananocrystalline Diamond Thin Films and Characterization of Mechanical Properties

2000 ◽  
Vol 657 ◽  
Author(s):  
A. V. Sumant ◽  
O. Auciello ◽  
A. R. Krauss ◽  
D. M. Gruen ◽  
D. Ersoy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Microwave Plasma ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Coarse Grained ◽  
Mems Devices ◽  
Ultrananocrystalline Diamond ◽  
Single Crystal Diamond

ABSTRACTThe mechanical, thermal, chemical, and tribological properties of diamond make it an ideal material for the fabrication of MEMS components. However, conventional CVD diamond deposition methods result in either a coarse-grained pure diamond structure that prevents high- resolution patterning, or in a fine-grained diamond film with a significant amount of intergranular non-diamond carbon. At Argonne National Laboratory, we are able to produce phase-pure ultrananocrystalline diamond (UNCD) films for the fabrication of MEMS components. UNCD is grown by microwave plasma CVD using C60-Ar or CH4-Ar plasmas, resulting in films that have 3-5 nm grain size, are 10-20 times smoother than conventionally grown diamond films, and can have mechanical properties similar to that of single crystal diamond. We used lithographic patterning, lift-off, and etching, in conjunction with the capability for growing UNCD on SiO2 to fabricate 2-D and 3-D UNCD-MEMS structures. We have performed initial characterization of mechanical properties by using nanoindentation and in-situ TEM indentor techniques. The values of Hardness (∼88 GPa) and Young's modulus (∼ 864 GPa) measured are very close to those of single crystal diamond (100 GPa and 1000 GPa respectively). The results show that UNCD is a promising material for future high performance MEMS devices.

Atomic-scale Characterization of HF-treated 4H-SiC(0001)1×1 Surfaces by Scanning Tunneling Microscopy

2007 ◽  
Vol 996 ◽  
Author(s):  
Kenta Arima ◽  
Hideyuki Hara ◽  
Yasuhisa Sano ◽  
Keita Yagi ◽  
Ryota Okamoto ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Chemical Preparation ◽  
Local Structures ◽  
Wet Chemical ◽  
Low Energy Electron ◽  
Scale Characterization

AbstractScanning tunneling microscopy (STM) observations are performed on 4H-SiC(0001) surfaces after wet-chemical preparation steps including HF treatments.1×1 structures are formed on a terrace together with other local structures. Their atomic images are investigated in conjunction with low-energy electron diffraction and electron spectroscopy for chemical analysis. It is suggested that each bright dot forming the 1×1 phase corresponds to an OH-terminated Si atom.

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