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Abhishek Sarkar - One of the best experts on this subject based on the ideXlab platform.

  • nanocrystalline multicomponent entropy stabilised transition metal oxides
    Journal of The European Ceramic Society, 2017
    Co-Authors: Abhishek Sarkar, Ruzica Djenadic, Nandhini J Usharani, Kevin P Sanghvi, Venkata Sai Kiran Chakravadhanula, Ashutosh S Gandhi, Horst Hahn, S S Bhattacharya
    Abstract:

    Abstract Multicomponent entropy stabilised oxides containing four and five metal elements in equiatomic amounts were successfully synthesised in nanocrystalline form by nebulised spray pyrolysis (NSP), flame spray pyrolysis (FSP) and reverse co-precipitation (RCP) techniques, demonstrating that entropy stabilisation of these recently discovered materials is independent of the synthesis method. Both 4- and 5-Cationic Systems, (Co,Mg,Ni,Zn)O and (Co,Cu,Mg,Ni,Zn)O, can be stabilised into a single rocksalt structure directly only using NSP, while in FSP and RCP, stabilisation can be achieved after thermal treatment. This result indicates, that in 5-Cationic NSP System configurational entropy is high enough to directly stabilise single rocksalt phase at lower temperature, while higher synthesis temperature is required to compensate the lower configurational entropy in 4-Cationic System. Retention of single-phase at room temperature indicates sluggish diffusion kinetics, making entropy stabilised phases quenchable.

S S Bhattacharya - One of the best experts on this subject based on the ideXlab platform.

  • nanocrystalline multicomponent entropy stabilised transition metal oxides
    Journal of The European Ceramic Society, 2017
    Co-Authors: Abhishek Sarkar, Ruzica Djenadic, Nandhini J Usharani, Kevin P Sanghvi, Venkata Sai Kiran Chakravadhanula, Ashutosh S Gandhi, Horst Hahn, S S Bhattacharya
    Abstract:

    Abstract Multicomponent entropy stabilised oxides containing four and five metal elements in equiatomic amounts were successfully synthesised in nanocrystalline form by nebulised spray pyrolysis (NSP), flame spray pyrolysis (FSP) and reverse co-precipitation (RCP) techniques, demonstrating that entropy stabilisation of these recently discovered materials is independent of the synthesis method. Both 4- and 5-Cationic Systems, (Co,Mg,Ni,Zn)O and (Co,Cu,Mg,Ni,Zn)O, can be stabilised into a single rocksalt structure directly only using NSP, while in FSP and RCP, stabilisation can be achieved after thermal treatment. This result indicates, that in 5-Cationic NSP System configurational entropy is high enough to directly stabilise single rocksalt phase at lower temperature, while higher synthesis temperature is required to compensate the lower configurational entropy in 4-Cationic System. Retention of single-phase at room temperature indicates sluggish diffusion kinetics, making entropy stabilised phases quenchable.

Pablo C. Schulz - One of the best experts on this subject based on the ideXlab platform.

  • the aqueous Cationic System sodium undecenoate dodecyltrimethylammonium bromide at low concentration
    Colloid and Polymer Science, 2004
    Co-Authors: María Belén Sierra, Marcela A. Morini, Pablo C. Schulz
    Abstract:

    The aqueous sodium undecenoate (SUD) –dodecyltrimethylammonium bromide (DTAB) catanionic System was studied at low concentration. The System did not precipitate, even at a 1:1 SUD:DTAB proportion, but showed the formation of a coacervate in a range of surfactant mixture compositions. Micelles have a preferential composition of 0.37 mole fraction of SUD. This behavior is attributed to the presence of the double bond at the distal extreme of the SUD molecule, which can form hydrogen bonds with water. Consequently, the –CH=CH2 group is situated at the interface between the hydrocarbon micelle core and water, reducing the interfacial free energy. Structural computations demonstrate that the mentioned SUD proportion produces complete coverage of the micelle surface by the double bonds.

Mark D Soucek - One of the best experts on this subject based on the ideXlab platform.

  • effect of introducing a Cationic System into a thiol ene photopolymerizable formulation
    Journal of Polymer Science Part A, 2007
    Co-Authors: Ricardo Acosta Ortiz, Bertha Puente A Urbina, Liliana Cabello V Valdez, Lydia Berlanga Duarte, Ramiro Guerrero Santos, Aida Garcia E Valdez, Mark D Soucek
    Abstract:

    Hybrid materials derived from a thiol-ene and Cationic polymerization were obtained from concomitant polymerization. The hybrid materials were cured by both photopolymerization and thermally induced polymerization. The kinetics of the photopolymerization were measured using time resolved-IR and optical pyrometry. The nucleophilic character of the polysulfide obtained initially in the thiol-ene polymerization inhibited the development of the Cationic photoinitiated polymerization of epoxy monomers. Besides, the epoxide groups underwent a proton catalyzed addition reaction with the thiols to form new sulfides groups in the reaction mixture. It is proposed that the formed sulfides can terminate the growing polyether chains forming dormant species like trialkylsulfonium salts. These salts promote the thermal polymerization of the epoxy monomer in a post treatment, producing hard and transparent materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4829–4843, 2007

Lopez-acevedo Olga - One of the best experts on this subject based on the ideXlab platform.

  • On the interaction between gold and silver metal atoms and DNA/RNA nucleobases -- a comprehensive computational study of ground state properties
    'Walter de Gruyter GmbH', 2020
    Co-Authors: Leal, Leonardo Andres Espinosa, Lopez-acevedo Olga
    Abstract:

    The interaction between metal atoms and nucleobases has been a topic of high interest due to the wide scientific and technological implications. Combining density functional theory simulations with a literature overview, we achieved an exhaustive study of the ground state electronic properties of DNA/RNA nucleobases interacting with gold and silver atoms at three charge states: neutral, Cationic, and anionic. We describe the nature of the stability and electronic properties in each hybrid metallic structure. In addition to the metal interacting with the five isolated nucleobases, we included their respective DNA-WC base pairs and one case with the protonated sugar-phosphate backbone. As a general trend, we discerned that the energetic ordering of isomers follows simple electrostatic rules as expected from previous studies. Also, we found that although the metal localizes almost all of the extra charge in the anionic System, a donation of charge is shared almost equally in the Cationic System. Furthermore, the frontier orbitals of the Cationic System tend to have more effects from the pairing and inclusion of the backbone than the anionic System. Finally, the electronic gap varies greatly among all of the considered structures and could be further used as a fingerprint when searching DNA-metal hybrid structures.Comment: 19 pages, 8 figure