Structural Refinement and Ferroic Properties in BiFeO3–Based Compounds

2011 ◽  
Vol 131 (1) ◽  
pp. 230-236 ◽  
Author(s):  
Luiz F. CóTica ◽  
Valdirlei F. Freitas ◽  
G. S. Dias ◽  
Ricardo A. M. Gotardo ◽  
Ivair A. Santos ◽  
...  
2004 ◽  
Vol 387-389 ◽  
pp. 809-816 ◽  
Author(s):  
F. Wetscher ◽  
A. Vorhauer ◽  
R. Stock ◽  
R. Pippan

2020 ◽  
Vol 59 (1) ◽  
pp. 506-513
Author(s):  
Denis A. Aksenov ◽  
Georgiy I. Raab ◽  
Rashid N. Asfandiyarov ◽  
Vladimir I. Semenov ◽  
Lev Sh. Shuster

AbstractAn increase in the service life of electrical products from copper and its alloys is directly related to an increase in the wear resistance of materials. Structural refinement and alloying with cadmium are known to have a positive effect on the strength characteristics and wear resistance of copper, which makes it possible, with a Cd content of 1% by weight, to increase the wear resistance of copper several times, but cadmium is considered an environmentally unsafe element. In this regard, the paper presents the results of studies of a widely used Cu-Cr-Zr alloy system in the ultrafine-grained (UFG) state, micro-alloyed with cadmium (0.2%, weight), in order to improve physical, mechanical, and operational properties, as well as environmental safety. Severe plastic deformation, providing structure refinement to ~150 nm, and microalloying with cadmium of a Cu-Cr-Zr system alloy, after a complete processing cycle, provides a tensile strength of 570±10 MPa and 67% electrical conductivity. At the same time, the abrasion resistance increases by 12 and 35% relative to the industrial systems Cu-Cd and Cu-Cr-Zr, respectively. The obtained characteristics are very promising for improving the operational properties of continuous welding tips, collector plates, and contact wires operating under conditions of intense wear.


2021 ◽  
Vol 22 (3) ◽  
pp. 1400
Author(s):  
Ciresthel Bello-Rios ◽  
Sarita Montaño ◽  
Olga Lilia Garibay-Cerdenares ◽  
Lilian Esmeralda Araujo-Arcos ◽  
Marco Antonio Leyva-Vázquez ◽  
...  

The oncogenic potential of high-risk human papillomavirus (HPV) is predicated on the production of the E6 and E7 oncoproteins, which are responsible for disrupting the control of the cell cycle. Epidemiological studies have proposed that the presence of the N29S and H51N variants of the HPV16 E7 protein is significantly associated with cervical cancer. It has been suggested that changes in the amino acid sequence of E7 variants may affect the oncoprotein 3D structure; however, this remains uncertain. An analysis of the structural differences of the HPV16 E7 protein and its variants (N29S and H51N) was performed through homology modeling and structural refinement by molecular dynamics simulation. We propose, for the first time, a 3D structure of the E7 reference protein and two of Its variants (N29S and H51N), and conclude that the mutations induced by the variants in N29S and H51N have a significant influence on the 3D structure of the E7 protein of HPV16, which could be related to the oncogenic capacity of this protein.


2007 ◽  
Vol 40 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Attilio Immirzi ◽  
Davide Alfano ◽  
Consiglia Tedesco

Two points of general interest in structural refinement of polymers based on internal coordinates are discussed: the chain orientation and the chain continuity. Using a proprietary computer program, based on revised approaches to these questions, the structure of polyisobutene has been reconsidered, using new X-ray diffraction measurements (Fuji image plate) and performing a structure refinement based on internal coordinates. Three refinement schemes, with a decreasing number of degrees of freedom, have been considered, with the conclusion that the distortion from the 83regular helix, claimed by Tadokoro [(1979).Structure of Crystalline Polymers, p. 136. New York: Wiley-Interscience], is confirmed, though lower than supposed. The new procedures implemented for chain orientation and chain continuity work excellently.


2009 ◽  
Vol 51 (7) ◽  
pp. 1420-1425 ◽  
Author(s):  
S. V. Akimov ◽  
E. F. Dudnik

Science ◽  
2021 ◽  
Vol 371 (6530) ◽  
pp. eabe5856
Author(s):  
Wonchull Kang ◽  
Chi Chung Lee ◽  
Andrew J. Jasniewski ◽  
Markus W. Ribbe ◽  
Yilin Hu

Peters et al. comment on our report of the dynamic structure of the nitrogenase metallocofactor during N2 reduction. Their claim that their independent structural refinement and consideration of biochemical data contradict our finding is incorrect and is strongly refuted by our biochemical and structural data that collectively and conclusively point to the binding of dinitrogen species to the nitrogenase cofactor.


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